aboutsummaryrefslogtreecommitdiffstatshomepage
path: root/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/libtests/pngvalid.c
diff options
context:
space:
mode:
Diffstat (limited to 'libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/libtests/pngvalid.c')
-rw-r--r--libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/libtests/pngvalid.c9837
1 files changed, 9837 insertions, 0 deletions
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/libtests/pngvalid.c b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/libtests/pngvalid.c
new file mode 100644
index 0000000..c7068fa
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/libtests/pngvalid.c
@@ -0,0 +1,9837 @@
1
2/* pngvalid.c - validate libpng by constructing then reading png files.
3 *
4 * Last changed in libpng 1.5.8 [%RDATE%]
5 * Copyright (c) 2012 Glenn Randers-Pehrson
6 * Written by John Cunningham Bowler
7 *
8 * This code is released under the libpng license.
9 * For conditions of distribution and use, see the disclaimer
10 * and license in png.h
11 *
12 * NOTES:
13 * This is a C program that is intended to be linked against libpng. It
14 * generates bitmaps internally, stores them as PNG files (using the
15 * sequential write code) then reads them back (using the sequential
16 * read code) and validates that the result has the correct data.
17 *
18 * The program can be modified and extended to test the correctness of
19 * transformations performed by libpng.
20 */
21
22#define _POSIX_SOURCE 1
23#define _ISOC99_SOURCE 1 /* For floating point */
24#define _GNU_SOURCE 1 /* For the floating point exception extension */
25
26#include <signal.h>
27
28#ifdef HAVE_FEENABLEEXCEPT
29# include <fenv.h>
30#endif
31
32/* Define the following to use this test against your installed libpng, rather
33 * than the one being built here:
34 */
35#ifdef PNG_FREESTANDING_TESTS
36# include <png.h>
37#else
38# include "../../png.h"
39#endif
40
41#if PNG_LIBPNG_VER < 10500
42/* This deliberately lacks the PNG_CONST. */
43typedef png_byte *png_const_bytep;
44
45/* This is copied from 1.5.1 png.h: */
46#define PNG_INTERLACE_ADAM7_PASSES 7
47#define PNG_PASS_START_ROW(pass) (((1U&~(pass))<<(3-((pass)>>1)))&7)
48#define PNG_PASS_START_COL(pass) (((1U& (pass))<<(3-(((pass)+1)>>1)))&7)
49#define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
50#define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
51#define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
52 -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
53#define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
54 -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
55#define PNG_ROW_FROM_PASS_ROW(yIn, pass) \
56 (((yIn)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
57#define PNG_COL_FROM_PASS_COL(xIn, pass) \
58 (((xIn)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
59#define PNG_PASS_MASK(pass,off) ( \
60 ((0x110145AFU>>(((7-(off))-(pass))<<2)) & 0xFU) | \
61 ((0x01145AF0U>>(((7-(off))-(pass))<<2)) & 0xF0U))
62#define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
63 ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
64#define PNG_COL_IN_INTERLACE_PASS(x, pass) \
65 ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
66
67/* These are needed too for the default build: */
68#define PNG_WRITE_16BIT_SUPPORTED
69#define PNG_READ_16BIT_SUPPORTED
70
71/* This comes from pnglibconf.h afer 1.5: */
72#define PNG_FP_1 100000
73#define PNG_GAMMA_THRESHOLD_FIXED\
74 ((png_fixed_point)(PNG_GAMMA_THRESHOLD * PNG_FP_1))
75#endif
76
77#include "zlib.h" /* For crc32 */
78
79#include <float.h> /* For floating point constants */
80#include <stdlib.h> /* For malloc */
81#include <string.h> /* For memcpy, memset */
82#include <math.h> /* For floor */
83
84/* Unused formal parameter errors are removed using the following macro which is
85 * expected to have no bad effects on performance.
86 */
87#ifndef UNUSED
88# if defined(__GNUC__) || defined(_MSC_VER)
89# define UNUSED(param) (void)param;
90# else
91# define UNUSED(param)
92# endif
93#endif
94
95/***************************** EXCEPTION HANDLING *****************************/
96#include "../visupng/cexcept.h"
97
98#ifdef __cplusplus
99# define this not_the_cpp_this
100# define new not_the_cpp_new
101# define voidcast(type, value) static_cast<type>(value)
102#else
103# define voidcast(type, value) (value)
104#endif /* __cplusplus */
105
106struct png_store;
107define_exception_type(struct png_store*);
108
109/* The following are macros to reduce typing everywhere where the well known
110 * name 'the_exception_context' must be defined.
111 */
112#define anon_context(ps) struct exception_context *the_exception_context = \
113 &(ps)->exception_context
114#define context(ps,fault) anon_context(ps); png_store *fault
115
116/******************************* UTILITIES ************************************/
117/* Error handling is particularly problematic in production code - error
118 * handlers often themselves have bugs which lead to programs that detect
119 * minor errors crashing. The following functions deal with one very
120 * common class of errors in error handlers - attempting to format error or
121 * warning messages into buffers that are too small.
122 */
123static size_t safecat(char *buffer, size_t bufsize, size_t pos,
124 PNG_CONST char *cat)
125{
126 while (pos < bufsize && cat != NULL && *cat != 0)
127 buffer[pos++] = *cat++;
128
129 if (pos >= bufsize)
130 pos = bufsize-1;
131
132 buffer[pos] = 0;
133 return pos;
134}
135
136static size_t safecatn(char *buffer, size_t bufsize, size_t pos, int n)
137{
138 char number[64];
139 sprintf(number, "%d", n);
140 return safecat(buffer, bufsize, pos, number);
141}
142
143#ifdef PNG_READ_TRANSFORMS_SUPPORTED
144static size_t safecatd(char *buffer, size_t bufsize, size_t pos, double d,
145 int precision)
146{
147 char number[64];
148 sprintf(number, "%.*f", precision, d);
149 return safecat(buffer, bufsize, pos, number);
150}
151#endif
152
153static PNG_CONST char invalid[] = "invalid";
154static PNG_CONST char sep[] = ": ";
155
156static PNG_CONST char *colour_types[8] =
157{
158 "grayscale", invalid, "truecolour", "indexed-colour",
159 "grayscale with alpha", invalid, "truecolour with alpha", invalid
160};
161
162/* Convert a double precision value to fixed point. */
163static png_fixed_point
164fix(double d)
165{
166 d = floor(d * PNG_FP_1 + .5);
167 return (png_fixed_point)d;
168}
169
170/* Generate random bytes. This uses a boring repeatable algorithm and it
171 * is implemented here so that it gives the same set of numbers on every
172 * architecture. It's a linear congruential generator (Knuth or Sedgewick
173 * "Algorithms") but it comes from the 'feedback taps' table in Horowitz and
174 * Hill, "The Art of Electronics".
175 */
176static void
177make_random_bytes(png_uint_32* seed, void* pv, size_t size)
178{
179 png_uint_32 u0 = seed[0], u1 = seed[1];
180 png_bytep bytes = voidcast(png_bytep, pv);
181
182 /* There are thirty three bits, the next bit in the sequence is bit-33 XOR
183 * bit-20. The top 1 bit is in u1, the bottom 32 are in u0.
184 */
185 size_t i;
186 for (i=0; i<size; ++i)
187 {
188 /* First generate 8 new bits then shift them in at the end. */
189 png_uint_32 u = ((u0 >> (20-8)) ^ ((u1 << 7) | (u0 >> (32-7)))) & 0xff;
190 u1 <<= 8;
191 u1 |= u0 >> 24;
192 u0 <<= 8;
193 u0 |= u;
194 *bytes++ = (png_byte)u;
195 }
196
197 seed[0] = u0;
198 seed[1] = u1;
199}
200
201static void
202make_four_random_bytes(png_uint_32* seed, png_bytep bytes)
203{
204 make_random_bytes(seed, bytes, 4);
205}
206
207static void
208randomize(void *pv, size_t size)
209{
210 static png_uint_32 random_seed[2] = {0x56789abc, 0xd};
211 make_random_bytes(random_seed, pv, size);
212}
213
214#define RANDOMIZE(this) randomize(&(this), sizeof (this))
215
216static unsigned int
217random_mod(unsigned int max)
218{
219 unsigned int x;
220
221 RANDOMIZE(x);
222
223 return x % max; /* 0 .. max-1 */
224}
225
226static int
227random_choice(void)
228{
229 unsigned char x;
230
231 RANDOMIZE(x);
232
233 return x & 1;
234}
235
236/* A numeric ID based on PNG file characteristics. The 'do_interlace' field
237 * simply records whether pngvalid did the interlace itself or whether it
238 * was done by libpng. Width and height must be less than 256. 'palette' is an
239 * index of the palette to use for formats with a palette (0 otherwise.)
240 */
241#define FILEID(col, depth, palette, interlace, width, height, do_interlace) \
242 ((png_uint_32)((col) + ((depth)<<3) + ((palette)<<8) + ((interlace)<<13) + \
243 (((do_interlace)!=0)<<15) + ((width)<<16) + ((height)<<24)))
244
245#define COL_FROM_ID(id) ((png_byte)((id)& 0x7U))
246#define DEPTH_FROM_ID(id) ((png_byte)(((id) >> 3) & 0x1fU))
247#define PALETTE_FROM_ID(id) ((int)(((id) >> 8) & 0x1f))
248#define INTERLACE_FROM_ID(id) ((int)(((id) >> 13) & 0x3))
249#define DO_INTERLACE_FROM_ID(id) ((int)(((id)>>15) & 1))
250#define WIDTH_FROM_ID(id) (((id)>>16) & 0xff)
251#define HEIGHT_FROM_ID(id) (((id)>>24) & 0xff)
252
253/* Utility to construct a standard name for a standard image. */
254static size_t
255standard_name(char *buffer, size_t bufsize, size_t pos, png_byte colour_type,
256 int bit_depth, int npalette, int interlace_type,
257 png_uint_32 w, png_uint_32 h, int do_interlace)
258{
259 pos = safecat(buffer, bufsize, pos, colour_types[colour_type]);
260 if (npalette > 0)
261 {
262 pos = safecat(buffer, bufsize, pos, "[");
263 pos = safecatn(buffer, bufsize, pos, npalette);
264 pos = safecat(buffer, bufsize, pos, "]");
265 }
266 pos = safecat(buffer, bufsize, pos, " ");
267 pos = safecatn(buffer, bufsize, pos, bit_depth);
268 pos = safecat(buffer, bufsize, pos, " bit");
269
270 if (interlace_type != PNG_INTERLACE_NONE)
271 {
272 pos = safecat(buffer, bufsize, pos, " interlaced");
273 if (do_interlace)
274 pos = safecat(buffer, bufsize, pos, "(pngvalid)");
275 else
276 pos = safecat(buffer, bufsize, pos, "(libpng)");
277 }
278
279 if (w > 0 || h > 0)
280 {
281 pos = safecat(buffer, bufsize, pos, " ");
282 pos = safecatn(buffer, bufsize, pos, w);
283 pos = safecat(buffer, bufsize, pos, "x");
284 pos = safecatn(buffer, bufsize, pos, h);
285 }
286
287 return pos;
288}
289
290static size_t
291standard_name_from_id(char *buffer, size_t bufsize, size_t pos, png_uint_32 id)
292{
293 return standard_name(buffer, bufsize, pos, COL_FROM_ID(id),
294 DEPTH_FROM_ID(id), PALETTE_FROM_ID(id), INTERLACE_FROM_ID(id),
295 WIDTH_FROM_ID(id), HEIGHT_FROM_ID(id), DO_INTERLACE_FROM_ID(id));
296}
297
298/* Convenience API and defines to list valid formats. Note that 16 bit read and
299 * write support is required to do 16 bit read tests (we must be able to make a
300 * 16 bit image to test!)
301 */
302#ifdef PNG_WRITE_16BIT_SUPPORTED
303# define WRITE_BDHI 4
304# ifdef PNG_READ_16BIT_SUPPORTED
305# define READ_BDHI 4
306# define DO_16BIT
307# endif
308#else
309# define WRITE_BDHI 3
310#endif
311#ifndef DO_16BIT
312# define READ_BDHI 3
313#endif
314
315/* The following defines the number of different palettes to generate for
316 * each log bit depth of a colour type 3 standard image.
317 */
318#define PALETTE_COUNT(bit_depth) ((bit_depth) > 4 ? 1 : 16)
319
320static int
321next_format(png_bytep colour_type, png_bytep bit_depth, int* palette_number)
322{
323 if (*bit_depth == 0)
324 {
325 *colour_type = 0, *bit_depth = 1, *palette_number = 0;
326 return 1;
327 }
328
329 if (*colour_type == 3)
330 {
331 /* Add multiple palettes for colour type 3. */
332 if (++*palette_number < PALETTE_COUNT(*bit_depth))
333 return 1;
334
335 *palette_number = 0;
336 }
337
338 *bit_depth = (png_byte)(*bit_depth << 1);
339
340 /* Palette images are restricted to 8 bit depth */
341 if (*bit_depth <= 8
342# ifdef DO_16BIT
343 || (*colour_type != 3 && *bit_depth <= 16)
344# endif
345 )
346 return 1;
347
348 /* Move to the next color type, or return 0 at the end. */
349 switch (*colour_type)
350 {
351 case 0:
352 *colour_type = 2;
353 *bit_depth = 8;
354 return 1;
355
356 case 2:
357 *colour_type = 3;
358 *bit_depth = 1;
359 return 1;
360
361 case 3:
362 *colour_type = 4;
363 *bit_depth = 8;
364 return 1;
365
366 case 4:
367 *colour_type = 6;
368 *bit_depth = 8;
369 return 1;
370
371 default:
372 return 0;
373 }
374}
375
376#ifdef PNG_READ_TRANSFORMS_SUPPORTED
377static unsigned int
378sample(png_const_bytep row, png_byte colour_type, png_byte bit_depth,
379 png_uint_32 x, unsigned int sample_index)
380{
381 png_uint_32 bit_index, result;
382
383 /* Find a sample index for the desired sample: */
384 x *= bit_depth;
385 bit_index = x;
386
387 if ((colour_type & 1) == 0) /* !palette */
388 {
389 if (colour_type & 2)
390 bit_index *= 3;
391
392 if (colour_type & 4)
393 bit_index += x; /* Alpha channel */
394
395 /* Multiple channels; select one: */
396 if (colour_type & (2+4))
397 bit_index += sample_index * bit_depth;
398 }
399
400 /* Return the sample from the row as an integer. */
401 row += bit_index >> 3;
402 result = *row;
403
404 if (bit_depth == 8)
405 return result;
406
407 else if (bit_depth > 8)
408 return (result << 8) + *++row;
409
410 /* Less than 8 bits per sample. */
411 bit_index &= 7;
412 return (result >> (8-bit_index-bit_depth)) & ((1U<<bit_depth)-1);
413}
414#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
415
416/* Copy a single pixel, of a given size, from one buffer to another -
417 * while this is basically bit addressed there is an implicit assumption
418 * that pixels 8 or more bits in size are byte aligned and that pixels
419 * do not otherwise cross byte boundaries. (This is, so far as I know,
420 * universally true in bitmap computer graphics. [JCB 20101212])
421 *
422 * NOTE: The to and from buffers may be the same.
423 */
424static void
425pixel_copy(png_bytep toBuffer, png_uint_32 toIndex,
426 png_const_bytep fromBuffer, png_uint_32 fromIndex, unsigned int pixelSize)
427{
428 /* Assume we can multiply by 'size' without overflow because we are
429 * just working in a single buffer.
430 */
431 toIndex *= pixelSize;
432 fromIndex *= pixelSize;
433 if (pixelSize < 8) /* Sub-byte */
434 {
435 /* Mask to select the location of the copied pixel: */
436 unsigned int destMask = ((1U<<pixelSize)-1) << (8-pixelSize-(toIndex&7));
437 /* The following read the entire pixels and clears the extra: */
438 unsigned int destByte = toBuffer[toIndex >> 3] & ~destMask;
439 unsigned int sourceByte = fromBuffer[fromIndex >> 3];
440
441 /* Don't rely on << or >> supporting '0' here, just in case: */
442 fromIndex &= 7;
443 if (fromIndex > 0) sourceByte <<= fromIndex;
444 if ((toIndex & 7) > 0) sourceByte >>= toIndex & 7;
445
446 toBuffer[toIndex >> 3] = (png_byte)(destByte | (sourceByte & destMask));
447 }
448 else /* One or more bytes */
449 memmove(toBuffer+(toIndex>>3), fromBuffer+(fromIndex>>3), pixelSize>>3);
450}
451
452/* Copy a complete row of pixels, taking into account potential partial
453 * bytes at the end.
454 */
455static void
456row_copy(png_bytep toBuffer, png_const_bytep fromBuffer, unsigned int bitWidth)
457{
458 memcpy(toBuffer, fromBuffer, bitWidth >> 3);
459
460 if ((bitWidth & 7) != 0)
461 {
462 unsigned int mask;
463
464 toBuffer += bitWidth >> 3;
465 fromBuffer += bitWidth >> 3;
466 /* The remaining bits are in the top of the byte, the mask is the bits to
467 * retain.
468 */
469 mask = 0xff >> (bitWidth & 7);
470 *toBuffer = (png_byte)((*toBuffer & mask) | (*fromBuffer & ~mask));
471 }
472}
473
474/* Compare pixels - they are assumed to start at the first byte in the
475 * given buffers.
476 */
477static int
478pixel_cmp(png_const_bytep pa, png_const_bytep pb, png_uint_32 bit_width)
479{
480#if PNG_LIBPNG_VER < 10506
481 if (memcmp(pa, pb, bit_width>>3) == 0)
482 {
483 png_uint_32 p;
484
485 if ((bit_width & 7) == 0) return 0;
486
487 /* Ok, any differences? */
488 p = pa[bit_width >> 3];
489 p ^= pb[bit_width >> 3];
490
491 if (p == 0) return 0;
492
493 /* There are, but they may not be significant, remove the bits
494 * after the end (the low order bits in PNG.)
495 */
496 bit_width &= 7;
497 p >>= 8-bit_width;
498
499 if (p == 0) return 0;
500 }
501#else
502 /* From libpng-1.5.6 the overwrite should be fixed, so compare the trailing
503 * bits too:
504 */
505 if (memcmp(pa, pb, (bit_width+7)>>3) == 0)
506 return 0;
507#endif
508
509 /* Return the index of the changed byte. */
510 {
511 png_uint_32 where = 0;
512
513 while (pa[where] == pb[where]) ++where;
514 return 1+where;
515 }
516}
517
518/*************************** BASIC PNG FILE WRITING ***************************/
519/* A png_store takes data from the sequential writer or provides data
520 * to the sequential reader. It can also store the result of a PNG
521 * write for later retrieval.
522 */
523#define STORE_BUFFER_SIZE 500 /* arbitrary */
524typedef struct png_store_buffer
525{
526 struct png_store_buffer* prev; /* NOTE: stored in reverse order */
527 png_byte buffer[STORE_BUFFER_SIZE];
528} png_store_buffer;
529
530#define FILE_NAME_SIZE 64
531
532typedef struct store_palette_entry /* record of a single palette entry */
533{
534 png_byte red;
535 png_byte green;
536 png_byte blue;
537 png_byte alpha;
538} store_palette_entry, store_palette[256];
539
540typedef struct png_store_file
541{
542 struct png_store_file* next; /* as many as you like... */
543 char name[FILE_NAME_SIZE];
544 png_uint_32 id; /* must be correct (see FILEID) */
545 png_size_t datacount; /* In this (the last) buffer */
546 png_store_buffer data; /* Last buffer in file */
547 int npalette; /* Number of entries in palette */
548 store_palette_entry* palette; /* May be NULL */
549} png_store_file;
550
551/* The following is a pool of memory allocated by a single libpng read or write
552 * operation.
553 */
554typedef struct store_pool
555{
556 struct png_store *store; /* Back pointer */
557 struct store_memory *list; /* List of allocated memory */
558 png_byte mark[4]; /* Before and after data */
559
560 /* Statistics for this run. */
561 png_alloc_size_t max; /* Maximum single allocation */
562 png_alloc_size_t current; /* Current allocation */
563 png_alloc_size_t limit; /* Highest current allocation */
564 png_alloc_size_t total; /* Total allocation */
565
566 /* Overall statistics (retained across successive runs). */
567 png_alloc_size_t max_max;
568 png_alloc_size_t max_limit;
569 png_alloc_size_t max_total;
570} store_pool;
571
572typedef struct png_store
573{
574 /* For cexcept.h exception handling - simply store one of these;
575 * the context is a self pointer but it may point to a different
576 * png_store (in fact it never does in this program.)
577 */
578 struct exception_context
579 exception_context;
580
581 unsigned int verbose :1;
582 unsigned int treat_warnings_as_errors :1;
583 unsigned int expect_error :1;
584 unsigned int expect_warning :1;
585 unsigned int saw_warning :1;
586 unsigned int speed :1;
587 unsigned int progressive :1; /* use progressive read */
588 unsigned int validated :1; /* used as a temporary flag */
589 int nerrors;
590 int nwarnings;
591 char test[128]; /* Name of test */
592 char error[256];
593
594 /* Read fields */
595 png_structp pread; /* Used to read a saved file */
596 png_infop piread;
597 png_store_file* current; /* Set when reading */
598 png_store_buffer* next; /* Set when reading */
599 png_size_t readpos; /* Position in *next */
600 png_byte* image; /* Buffer for reading interlaced images */
601 png_size_t cb_image; /* Size of this buffer */
602 png_size_t cb_row; /* Row size of the image(s) */
603 png_uint_32 image_h; /* Number of rows in a single image */
604 store_pool read_memory_pool;
605
606 /* Write fields */
607 png_store_file* saved;
608 png_structp pwrite; /* Used when writing a new file */
609 png_infop piwrite;
610 png_size_t writepos; /* Position in .new */
611 char wname[FILE_NAME_SIZE];
612 png_store_buffer new; /* The end of the new PNG file being written. */
613 store_pool write_memory_pool;
614 store_palette_entry* palette;
615 int npalette;
616} png_store;
617
618/* Initialization and cleanup */
619static void
620store_pool_mark(png_bytep mark)
621{
622 static png_uint_32 store_seed[2] = { 0x12345678, 1};
623
624 make_four_random_bytes(store_seed, mark);
625}
626
627/* Use this for random 32 bit values; this function makes sure the result is
628 * non-zero.
629 */
630static png_uint_32
631random_32(void)
632{
633
634 for(;;)
635 {
636 png_byte mark[4];
637 png_uint_32 result;
638
639 store_pool_mark(mark);
640 result = png_get_uint_32(mark);
641
642 if (result != 0)
643 return result;
644 }
645}
646
647static void
648store_pool_init(png_store *ps, store_pool *pool)
649{
650 memset(pool, 0, sizeof *pool);
651
652 pool->store = ps;
653 pool->list = NULL;
654 pool->max = pool->current = pool->limit = pool->total = 0;
655 pool->max_max = pool->max_limit = pool->max_total = 0;
656 store_pool_mark(pool->mark);
657}
658
659static void
660store_init(png_store* ps)
661{
662 memset(ps, 0, sizeof *ps);
663 init_exception_context(&ps->exception_context);
664 store_pool_init(ps, &ps->read_memory_pool);
665 store_pool_init(ps, &ps->write_memory_pool);
666 ps->verbose = 0;
667 ps->treat_warnings_as_errors = 0;
668 ps->expect_error = 0;
669 ps->expect_warning = 0;
670 ps->saw_warning = 0;
671 ps->speed = 0;
672 ps->progressive = 0;
673 ps->validated = 0;
674 ps->nerrors = ps->nwarnings = 0;
675 ps->pread = NULL;
676 ps->piread = NULL;
677 ps->saved = ps->current = NULL;
678 ps->next = NULL;
679 ps->readpos = 0;
680 ps->image = NULL;
681 ps->cb_image = 0;
682 ps->cb_row = 0;
683 ps->image_h = 0;
684 ps->pwrite = NULL;
685 ps->piwrite = NULL;
686 ps->writepos = 0;
687 ps->new.prev = NULL;
688 ps->palette = NULL;
689 ps->npalette = 0;
690}
691
692static void
693store_freebuffer(png_store_buffer* psb)
694{
695 if (psb->prev)
696 {
697 store_freebuffer(psb->prev);
698 free(psb->prev);
699 psb->prev = NULL;
700 }
701}
702
703static void
704store_freenew(png_store *ps)
705{
706 store_freebuffer(&ps->new);
707 ps->writepos = 0;
708 if (ps->palette != NULL)
709 {
710 free(ps->palette);
711 ps->palette = NULL;
712 ps->npalette = 0;
713 }
714}
715
716static void
717store_storenew(png_store *ps)
718{
719 png_store_buffer *pb;
720
721 if (ps->writepos != STORE_BUFFER_SIZE)
722 png_error(ps->pwrite, "invalid store call");
723
724 pb = voidcast(png_store_buffer*, malloc(sizeof *pb));
725
726 if (pb == NULL)
727 png_error(ps->pwrite, "store new: OOM");
728
729 *pb = ps->new;
730 ps->new.prev = pb;
731 ps->writepos = 0;
732}
733
734static void
735store_freefile(png_store_file **ppf)
736{
737 if (*ppf != NULL)
738 {
739 store_freefile(&(*ppf)->next);
740
741 store_freebuffer(&(*ppf)->data);
742 (*ppf)->datacount = 0;
743 if ((*ppf)->palette != NULL)
744 {
745 free((*ppf)->palette);
746 (*ppf)->palette = NULL;
747 (*ppf)->npalette = 0;
748 }
749 free(*ppf);
750 *ppf = NULL;
751 }
752}
753
754/* Main interface to file storeage, after writing a new PNG file (see the API
755 * below) call store_storefile to store the result with the given name and id.
756 */
757static void
758store_storefile(png_store *ps, png_uint_32 id)
759{
760 png_store_file *pf = voidcast(png_store_file*, malloc(sizeof *pf));
761 if (pf == NULL)
762 png_error(ps->pwrite, "storefile: OOM");
763 safecat(pf->name, sizeof pf->name, 0, ps->wname);
764 pf->id = id;
765 pf->data = ps->new;
766 pf->datacount = ps->writepos;
767 ps->new.prev = NULL;
768 ps->writepos = 0;
769 pf->palette = ps->palette;
770 pf->npalette = ps->npalette;
771 ps->palette = 0;
772 ps->npalette = 0;
773
774 /* And save it. */
775 pf->next = ps->saved;
776 ps->saved = pf;
777}
778
779/* Generate an error message (in the given buffer) */
780static size_t
781store_message(png_store *ps, png_structp pp, char *buffer, size_t bufsize,
782 size_t pos, PNG_CONST char *msg)
783{
784 if (pp != NULL && pp == ps->pread)
785 {
786 /* Reading a file */
787 pos = safecat(buffer, bufsize, pos, "read: ");
788
789 if (ps->current != NULL)
790 {
791 pos = safecat(buffer, bufsize, pos, ps->current->name);
792 pos = safecat(buffer, bufsize, pos, sep);
793 }
794 }
795
796 else if (pp != NULL && pp == ps->pwrite)
797 {
798 /* Writing a file */
799 pos = safecat(buffer, bufsize, pos, "write: ");
800 pos = safecat(buffer, bufsize, pos, ps->wname);
801 pos = safecat(buffer, bufsize, pos, sep);
802 }
803
804 else
805 {
806 /* Neither reading nor writing (or a memory error in struct delete) */
807 pos = safecat(buffer, bufsize, pos, "pngvalid: ");
808 }
809
810 if (ps->test[0] != 0)
811 {
812 pos = safecat(buffer, bufsize, pos, ps->test);
813 pos = safecat(buffer, bufsize, pos, sep);
814 }
815 pos = safecat(buffer, bufsize, pos, msg);
816 return pos;
817}
818
819/* Verbose output to the error stream: */
820static void
821store_verbose(png_store *ps, png_structp pp, png_const_charp prefix,
822 png_const_charp message)
823{
824 char buffer[512];
825
826 if (prefix)
827 fputs(prefix, stderr);
828
829 (void)store_message(ps, pp, buffer, sizeof buffer, 0, message);
830 fputs(buffer, stderr);
831 fputc('\n', stderr);
832}
833
834/* Log an error or warning - the relevant count is always incremented. */
835static void
836store_log(png_store* ps, png_structp pp, png_const_charp message, int is_error)
837{
838 /* The warning is copied to the error buffer if there are no errors and it is
839 * the first warning. The error is copied to the error buffer if it is the
840 * first error (overwriting any prior warnings).
841 */
842 if (is_error ? (ps->nerrors)++ == 0 :
843 (ps->nwarnings)++ == 0 && ps->nerrors == 0)
844 store_message(ps, pp, ps->error, sizeof ps->error, 0, message);
845
846 if (ps->verbose)
847 store_verbose(ps, pp, is_error ? "error: " : "warning: ", message);
848}
849
850/* Internal error function, called with a png_store but no libpng stuff. */
851static void
852internal_error(png_store *ps, png_const_charp message)
853{
854 store_log(ps, NULL, message, 1 /* error */);
855
856 /* And finally throw an exception. */
857 {
858 struct exception_context *the_exception_context = &ps->exception_context;
859 Throw ps;
860 }
861}
862
863/* Functions to use as PNG callbacks. */
864static void
865store_error(png_structp pp, png_const_charp message) /* PNG_NORETURN */
866{
867 png_store *ps = voidcast(png_store*, png_get_error_ptr(pp));
868
869 if (!ps->expect_error)
870 store_log(ps, pp, message, 1 /* error */);
871
872 /* And finally throw an exception. */
873 {
874 struct exception_context *the_exception_context = &ps->exception_context;
875 Throw ps;
876 }
877}
878
879static void
880store_warning(png_structp pp, png_const_charp message)
881{
882 png_store *ps = voidcast(png_store*, png_get_error_ptr(pp));
883
884 if (!ps->expect_warning)
885 store_log(ps, pp, message, 0 /* warning */);
886 else
887 ps->saw_warning = 1;
888}
889
890/* These somewhat odd functions are used when reading an image to ensure that
891 * the buffer is big enough, the png_structp is for errors.
892 */
893/* Return a single row from the correct image. */
894static png_bytep
895store_image_row(PNG_CONST png_store* ps, png_structp pp, int nImage,
896 png_uint_32 y)
897{
898 png_size_t coffset = (nImage * ps->image_h + y) * (ps->cb_row + 5) + 2;
899
900 if (ps->image == NULL)
901 png_error(pp, "no allocated image");
902
903 if (coffset + ps->cb_row + 3 > ps->cb_image)
904 png_error(pp, "image too small");
905
906 return ps->image + coffset;
907}
908
909static void
910store_image_free(png_store *ps, png_structp pp)
911{
912 if (ps->image != NULL)
913 {
914 png_bytep image = ps->image;
915
916 if (image[-1] != 0xed || image[ps->cb_image] != 0xfe)
917 {
918 if (pp != NULL)
919 png_error(pp, "png_store image overwrite (1)");
920 else
921 store_log(ps, NULL, "png_store image overwrite (2)", 1);
922 }
923
924 ps->image = NULL;
925 ps->cb_image = 0;
926 --image;
927 free(image);
928 }
929}
930
931static void
932store_ensure_image(png_store *ps, png_structp pp, int nImages, png_size_t cbRow,
933 png_uint_32 cRows)
934{
935 png_size_t cb = nImages * cRows * (cbRow + 5);
936
937 if (ps->cb_image < cb)
938 {
939 png_bytep image;
940
941 store_image_free(ps, pp);
942
943 /* The buffer is deliberately mis-aligned. */
944 image = voidcast(png_bytep, malloc(cb+2));
945 if (image == NULL)
946 {
947 /* Called from the startup - ignore the error for the moment. */
948 if (pp == NULL)
949 return;
950
951 png_error(pp, "OOM allocating image buffer");
952 }
953
954 /* These magic tags are used to detect overwrites above. */
955 ++image;
956 image[-1] = 0xed;
957 image[cb] = 0xfe;
958
959 ps->image = image;
960 ps->cb_image = cb;
961 }
962
963 /* We have an adequate sized image; lay out the rows. There are 2 bytes at
964 * the start and three at the end of each (this ensures that the row
965 * alignment starts out odd - 2+1 and changes for larger images on each row.)
966 */
967 ps->cb_row = cbRow;
968 ps->image_h = cRows;
969
970 /* For error checking, the whole buffer is set to 10110010 (0xb2 - 178).
971 * This deliberately doesn't match the bits in the size test image which are
972 * outside the image; these are set to 0xff (all 1). To make the row
973 * comparison work in the 'size' test case the size rows are pre-initialized
974 * to the same value prior to calling 'standard_row'.
975 */
976 memset(ps->image, 178, cb);
977
978 /* Then put in the marks. */
979 while (--nImages >= 0)
980 {
981 png_uint_32 y;
982
983 for (y=0; y<cRows; ++y)
984 {
985 png_bytep row = store_image_row(ps, pp, nImages, y);
986
987 /* The markers: */
988 row[-2] = 190;
989 row[-1] = 239;
990 row[cbRow] = 222;
991 row[cbRow+1] = 173;
992 row[cbRow+2] = 17;
993 }
994 }
995}
996
997static void
998store_image_check(PNG_CONST png_store* ps, png_structp pp, int iImage)
999{
1000 png_const_bytep image = ps->image;
1001
1002 if (image[-1] != 0xed || image[ps->cb_image] != 0xfe)
1003 png_error(pp, "image overwrite");
1004 else
1005 {
1006 png_size_t cbRow = ps->cb_row;
1007 png_uint_32 rows = ps->image_h;
1008
1009 image += iImage * (cbRow+5) * ps->image_h;
1010
1011 image += 2; /* skip image first row markers */
1012
1013 while (rows-- > 0)
1014 {
1015 if (image[-2] != 190 || image[-1] != 239)
1016 png_error(pp, "row start overwritten");
1017
1018 if (image[cbRow] != 222 || image[cbRow+1] != 173 ||
1019 image[cbRow+2] != 17)
1020 png_error(pp, "row end overwritten");
1021
1022 image += cbRow+5;
1023 }
1024 }
1025}
1026
1027static void
1028store_write(png_structp pp, png_bytep pb, png_size_t st)
1029{
1030 png_store *ps = voidcast(png_store*, png_get_io_ptr(pp));
1031
1032 if (ps->pwrite != pp)
1033 png_error(pp, "store state damaged");
1034
1035 while (st > 0)
1036 {
1037 size_t cb;
1038
1039 if (ps->writepos >= STORE_BUFFER_SIZE)
1040 store_storenew(ps);
1041
1042 cb = st;
1043
1044 if (cb > STORE_BUFFER_SIZE - ps->writepos)
1045 cb = STORE_BUFFER_SIZE - ps->writepos;
1046
1047 memcpy(ps->new.buffer + ps->writepos, pb, cb);
1048 pb += cb;
1049 st -= cb;
1050 ps->writepos += cb;
1051 }
1052}
1053
1054static void
1055store_flush(png_structp pp)
1056{
1057 UNUSED(pp) /*DOES NOTHING*/
1058}
1059
1060static size_t
1061store_read_buffer_size(png_store *ps)
1062{
1063 /* Return the bytes available for read in the current buffer. */
1064 if (ps->next != &ps->current->data)
1065 return STORE_BUFFER_SIZE;
1066
1067 return ps->current->datacount;
1068}
1069
1070#ifdef PNG_READ_TRANSFORMS_SUPPORTED
1071/* Return total bytes available for read. */
1072static size_t
1073store_read_buffer_avail(png_store *ps)
1074{
1075 if (ps->current != NULL && ps->next != NULL)
1076 {
1077 png_store_buffer *next = &ps->current->data;
1078 size_t cbAvail = ps->current->datacount;
1079
1080 while (next != ps->next && next != NULL)
1081 {
1082 next = next->prev;
1083 cbAvail += STORE_BUFFER_SIZE;
1084 }
1085
1086 if (next != ps->next)
1087 png_error(ps->pread, "buffer read error");
1088
1089 if (cbAvail > ps->readpos)
1090 return cbAvail - ps->readpos;
1091 }
1092
1093 return 0;
1094}
1095#endif
1096
1097static int
1098store_read_buffer_next(png_store *ps)
1099{
1100 png_store_buffer *pbOld = ps->next;
1101 png_store_buffer *pbNew = &ps->current->data;
1102 if (pbOld != pbNew)
1103 {
1104 while (pbNew != NULL && pbNew->prev != pbOld)
1105 pbNew = pbNew->prev;
1106
1107 if (pbNew != NULL)
1108 {
1109 ps->next = pbNew;
1110 ps->readpos = 0;
1111 return 1;
1112 }
1113
1114 png_error(ps->pread, "buffer lost");
1115 }
1116
1117 return 0; /* EOF or error */
1118}
1119
1120/* Need separate implementation and callback to allow use of the same code
1121 * during progressive read, where the io_ptr is set internally by libpng.
1122 */
1123static void
1124store_read_imp(png_store *ps, png_bytep pb, png_size_t st)
1125{
1126 if (ps->current == NULL || ps->next == NULL)
1127 png_error(ps->pread, "store state damaged");
1128
1129 while (st > 0)
1130 {
1131 size_t cbAvail = store_read_buffer_size(ps) - ps->readpos;
1132
1133 if (cbAvail > 0)
1134 {
1135 if (cbAvail > st) cbAvail = st;
1136 memcpy(pb, ps->next->buffer + ps->readpos, cbAvail);
1137 st -= cbAvail;
1138 pb += cbAvail;
1139 ps->readpos += cbAvail;
1140 }
1141
1142 else if (!store_read_buffer_next(ps))
1143 png_error(ps->pread, "read beyond end of file");
1144 }
1145}
1146
1147static void
1148store_read(png_structp pp, png_bytep pb, png_size_t st)
1149{
1150 png_store *ps = voidcast(png_store*, png_get_io_ptr(pp));
1151
1152 if (ps == NULL || ps->pread != pp)
1153 png_error(pp, "bad store read call");
1154
1155 store_read_imp(ps, pb, st);
1156}
1157
1158static void
1159store_progressive_read(png_store *ps, png_structp pp, png_infop pi)
1160{
1161 /* Notice that a call to store_read will cause this function to fail because
1162 * readpos will be set.
1163 */
1164 if (ps->pread != pp || ps->current == NULL || ps->next == NULL)
1165 png_error(pp, "store state damaged (progressive)");
1166
1167 do
1168 {
1169 if (ps->readpos != 0)
1170 png_error(pp, "store_read called during progressive read");
1171
1172 png_process_data(pp, pi, ps->next->buffer, store_read_buffer_size(ps));
1173 }
1174 while (store_read_buffer_next(ps));
1175}
1176
1177/* The caller must fill this in: */
1178static store_palette_entry *
1179store_write_palette(png_store *ps, int npalette)
1180{
1181 if (ps->pwrite == NULL)
1182 store_log(ps, NULL, "attempt to write palette without write stream", 1);
1183
1184 if (ps->palette != NULL)
1185 png_error(ps->pwrite, "multiple store_write_palette calls");
1186
1187 /* This function can only return NULL if called with '0'! */
1188 if (npalette > 0)
1189 {
1190 ps->palette = voidcast(store_palette_entry*, malloc(npalette *
1191 sizeof *ps->palette));
1192
1193 if (ps->palette == NULL)
1194 png_error(ps->pwrite, "store new palette: OOM");
1195
1196 ps->npalette = npalette;
1197 }
1198
1199 return ps->palette;
1200}
1201
1202static store_palette_entry *
1203store_current_palette(png_store *ps, int *npalette)
1204{
1205 /* This is an internal error (the call has been made outside a read
1206 * operation.)
1207 */
1208 if (ps->current == NULL)
1209 store_log(ps, ps->pread, "no current stream for palette", 1);
1210
1211 /* The result may be null if there is no palette. */
1212 *npalette = ps->current->npalette;
1213 return ps->current->palette;
1214}
1215
1216/***************************** MEMORY MANAGEMENT*** ***************************/
1217/* A store_memory is simply the header for an allocated block of memory. The
1218 * pointer returned to libpng is just after the end of the header block, the
1219 * allocated memory is followed by a second copy of the 'mark'.
1220 */
1221typedef struct store_memory
1222{
1223 store_pool *pool; /* Originating pool */
1224 struct store_memory *next; /* Singly linked list */
1225 png_alloc_size_t size; /* Size of memory allocated */
1226 png_byte mark[4]; /* ID marker */
1227} store_memory;
1228
1229/* Handle a fatal error in memory allocation. This calls png_error if the
1230 * libpng struct is non-NULL, else it outputs a message and returns. This means
1231 * that a memory problem while libpng is running will abort (png_error) the
1232 * handling of particular file while one in cleanup (after the destroy of the
1233 * struct has returned) will simply keep going and free (or attempt to free)
1234 * all the memory.
1235 */
1236static void
1237store_pool_error(png_store *ps, png_structp pp, PNG_CONST char *msg)
1238{
1239 if (pp != NULL)
1240 png_error(pp, msg);
1241
1242 /* Else we have to do it ourselves. png_error eventually calls store_log,
1243 * above. store_log accepts a NULL png_structp - it just changes what gets
1244 * output by store_message.
1245 */
1246 store_log(ps, pp, msg, 1 /* error */);
1247}
1248
1249static void
1250store_memory_free(png_structp pp, store_pool *pool, store_memory *memory)
1251{
1252 /* Note that pp may be NULL (see store_pool_delete below), the caller has
1253 * found 'memory' in pool->list *and* unlinked this entry, so this is a valid
1254 * pointer (for sure), but the contents may have been trashed.
1255 */
1256 if (memory->pool != pool)
1257 store_pool_error(pool->store, pp, "memory corrupted (pool)");
1258
1259 else if (memcmp(memory->mark, pool->mark, sizeof memory->mark) != 0)
1260 store_pool_error(pool->store, pp, "memory corrupted (start)");
1261
1262 /* It should be safe to read the size field now. */
1263 else
1264 {
1265 png_alloc_size_t cb = memory->size;
1266
1267 if (cb > pool->max)
1268 store_pool_error(pool->store, pp, "memory corrupted (size)");
1269
1270 else if (memcmp((png_bytep)(memory+1)+cb, pool->mark, sizeof pool->mark)
1271 != 0)
1272 store_pool_error(pool->store, pp, "memory corrupted (end)");
1273
1274 /* Finally give the library a chance to find problems too: */
1275 else
1276 {
1277 pool->current -= cb;
1278 free(memory);
1279 }
1280 }
1281}
1282
1283static void
1284store_pool_delete(png_store *ps, store_pool *pool)
1285{
1286 if (pool->list != NULL)
1287 {
1288 fprintf(stderr, "%s: %s %s: memory lost (list follows):\n", ps->test,
1289 pool == &ps->read_memory_pool ? "read" : "write",
1290 pool == &ps->read_memory_pool ? (ps->current != NULL ?
1291 ps->current->name : "unknown file") : ps->wname);
1292 ++ps->nerrors;
1293
1294 do
1295 {
1296 store_memory *next = pool->list;
1297 pool->list = next->next;
1298 next->next = NULL;
1299
1300 fprintf(stderr, "\t%lu bytes @ %p\n",
1301 (unsigned long)next->size, (PNG_CONST void*)(next+1));
1302 /* The NULL means this will always return, even if the memory is
1303 * corrupted.
1304 */
1305 store_memory_free(NULL, pool, next);
1306 }
1307 while (pool->list != NULL);
1308 }
1309
1310 /* And reset the other fields too for the next time. */
1311 if (pool->max > pool->max_max) pool->max_max = pool->max;
1312 pool->max = 0;
1313 if (pool->current != 0) /* unexpected internal error */
1314 fprintf(stderr, "%s: %s %s: memory counter mismatch (internal error)\n",
1315 ps->test, pool == &ps->read_memory_pool ? "read" : "write",
1316 pool == &ps->read_memory_pool ? (ps->current != NULL ?
1317 ps->current->name : "unknown file") : ps->wname);
1318 pool->current = 0;
1319
1320 if (pool->limit > pool->max_limit)
1321 pool->max_limit = pool->limit;
1322
1323 pool->limit = 0;
1324
1325 if (pool->total > pool->max_total)
1326 pool->max_total = pool->total;
1327
1328 pool->total = 0;
1329
1330 /* Get a new mark too. */
1331 store_pool_mark(pool->mark);
1332}
1333
1334/* The memory callbacks: */
1335static png_voidp
1336store_malloc(png_structp pp, png_alloc_size_t cb)
1337{
1338 store_pool *pool = voidcast(store_pool*, png_get_mem_ptr(pp));
1339 store_memory *new = voidcast(store_memory*, malloc(cb + (sizeof *new) +
1340 (sizeof pool->mark)));
1341
1342 if (new != NULL)
1343 {
1344 if (cb > pool->max)
1345 pool->max = cb;
1346
1347 pool->current += cb;
1348
1349 if (pool->current > pool->limit)
1350 pool->limit = pool->current;
1351
1352 pool->total += cb;
1353
1354 new->size = cb;
1355 memcpy(new->mark, pool->mark, sizeof new->mark);
1356 memcpy((png_byte*)(new+1) + cb, pool->mark, sizeof pool->mark);
1357 new->pool = pool;
1358 new->next = pool->list;
1359 pool->list = new;
1360 ++new;
1361 }
1362
1363 else
1364 {
1365 /* NOTE: the PNG user malloc function cannot use the png_ptr it is passed
1366 * other than to retrieve the allocation pointer! libpng calls the
1367 * store_malloc callback in two basic cases:
1368 *
1369 * 1) From png_malloc; png_malloc will do a png_error itself if NULL is
1370 * returned.
1371 * 2) From png_struct or png_info structure creation; png_malloc is
1372 * to return so cleanup can be performed.
1373 *
1374 * To handle this store_malloc can log a message, but can't do anything
1375 * else.
1376 */
1377 store_log(pool->store, pp, "out of memory", 1 /* is_error */);
1378 }
1379
1380 return new;
1381}
1382
1383static void
1384store_free(png_structp pp, png_voidp memory)
1385{
1386 store_pool *pool = voidcast(store_pool*, png_get_mem_ptr(pp));
1387 store_memory *this = voidcast(store_memory*, memory), **test;
1388
1389 /* Because libpng calls store_free with a dummy png_struct when deleting
1390 * png_struct or png_info via png_destroy_struct_2 it is necessary to check
1391 * the passed in png_structp to ensure it is valid, and not pass it to
1392 * png_error if it is not.
1393 */
1394 if (pp != pool->store->pread && pp != pool->store->pwrite)
1395 pp = NULL;
1396
1397 /* First check that this 'memory' really is valid memory - it must be in the
1398 * pool list. If it is, use the shared memory_free function to free it.
1399 */
1400 --this;
1401 for (test = &pool->list; *test != this; test = &(*test)->next)
1402 {
1403 if (*test == NULL)
1404 {
1405 store_pool_error(pool->store, pp, "bad pointer to free");
1406 return;
1407 }
1408 }
1409
1410 /* Unlink this entry, *test == this. */
1411 *test = this->next;
1412 this->next = NULL;
1413 store_memory_free(pp, pool, this);
1414}
1415
1416/* Setup functions. */
1417/* Cleanup when aborting a write or after storing the new file. */
1418static void
1419store_write_reset(png_store *ps)
1420{
1421 if (ps->pwrite != NULL)
1422 {
1423 anon_context(ps);
1424
1425 Try
1426 png_destroy_write_struct(&ps->pwrite, &ps->piwrite);
1427
1428 Catch_anonymous
1429 {
1430 /* memory corruption: continue. */
1431 }
1432
1433 ps->pwrite = NULL;
1434 ps->piwrite = NULL;
1435 }
1436
1437 /* And make sure that all the memory has been freed - this will output
1438 * spurious errors in the case of memory corruption above, but this is safe.
1439 */
1440 store_pool_delete(ps, &ps->write_memory_pool);
1441
1442 store_freenew(ps);
1443}
1444
1445/* The following is the main write function, it returns a png_struct and,
1446 * optionally, a png_info suitable for writiing a new PNG file. Use
1447 * store_storefile above to record this file after it has been written. The
1448 * returned libpng structures as destroyed by store_write_reset above.
1449 */
1450static png_structp
1451set_store_for_write(png_store *ps, png_infopp ppi,
1452 PNG_CONST char * volatile name)
1453{
1454 anon_context(ps);
1455
1456 Try
1457 {
1458 if (ps->pwrite != NULL)
1459 png_error(ps->pwrite, "write store already in use");
1460
1461 store_write_reset(ps);
1462 safecat(ps->wname, sizeof ps->wname, 0, name);
1463
1464 /* Don't do the slow memory checks if doing a speed test. */
1465 if (ps->speed)
1466 ps->pwrite = png_create_write_struct(PNG_LIBPNG_VER_STRING,
1467 ps, store_error, store_warning);
1468
1469 else
1470 ps->pwrite = png_create_write_struct_2(PNG_LIBPNG_VER_STRING,
1471 ps, store_error, store_warning, &ps->write_memory_pool,
1472 store_malloc, store_free);
1473
1474 png_set_write_fn(ps->pwrite, ps, store_write, store_flush);
1475
1476 if (ppi != NULL)
1477 *ppi = ps->piwrite = png_create_info_struct(ps->pwrite);
1478 }
1479
1480 Catch_anonymous
1481 return NULL;
1482
1483 return ps->pwrite;
1484}
1485
1486/* Cleanup when finished reading (either due to error or in the success case).
1487 */
1488static void
1489store_read_reset(png_store *ps)
1490{
1491 if (ps->pread != NULL)
1492 {
1493 anon_context(ps);
1494
1495 Try
1496 png_destroy_read_struct(&ps->pread, &ps->piread, NULL);
1497
1498 Catch_anonymous
1499 {
1500 /* error already output: continue */
1501 }
1502
1503 ps->pread = NULL;
1504 ps->piread = NULL;
1505 }
1506
1507 /* Always do this to be safe. */
1508 store_pool_delete(ps, &ps->read_memory_pool);
1509
1510 ps->current = NULL;
1511 ps->next = NULL;
1512 ps->readpos = 0;
1513 ps->validated = 0;
1514}
1515
1516static void
1517store_read_set(png_store *ps, png_uint_32 id)
1518{
1519 png_store_file *pf = ps->saved;
1520
1521 while (pf != NULL)
1522 {
1523 if (pf->id == id)
1524 {
1525 ps->current = pf;
1526 ps->next = NULL;
1527 store_read_buffer_next(ps);
1528 return;
1529 }
1530
1531 pf = pf->next;
1532 }
1533
1534 {
1535 size_t pos;
1536 char msg[FILE_NAME_SIZE+64];
1537
1538 pos = standard_name_from_id(msg, sizeof msg, 0, id);
1539 pos = safecat(msg, sizeof msg, pos, ": file not found");
1540 png_error(ps->pread, msg);
1541 }
1542}
1543
1544/* The main interface for reading a saved file - pass the id number of the file
1545 * to retrieve. Ids must be unique or the earlier file will be hidden. The API
1546 * returns a png_struct and, optionally, a png_info. Both of these will be
1547 * destroyed by store_read_reset above.
1548 */
1549static png_structp
1550set_store_for_read(png_store *ps, png_infopp ppi, png_uint_32 id,
1551 PNG_CONST char *name)
1552{
1553 /* Set the name for png_error */
1554 safecat(ps->test, sizeof ps->test, 0, name);
1555
1556 if (ps->pread != NULL)
1557 png_error(ps->pread, "read store already in use");
1558
1559 store_read_reset(ps);
1560
1561 /* Both the create APIs can return NULL if used in their default mode
1562 * (because there is no other way of handling an error because the jmp_buf
1563 * by default is stored in png_struct and that has not been allocated!)
1564 * However, given that store_error works correctly in these circumstances
1565 * we don't ever expect NULL in this program.
1566 */
1567 if (ps->speed)
1568 ps->pread = png_create_read_struct(PNG_LIBPNG_VER_STRING, ps,
1569 store_error, store_warning);
1570
1571 else
1572 ps->pread = png_create_read_struct_2(PNG_LIBPNG_VER_STRING, ps,
1573 store_error, store_warning, &ps->read_memory_pool, store_malloc,
1574 store_free);
1575
1576 if (ps->pread == NULL)
1577 {
1578 struct exception_context *the_exception_context = &ps->exception_context;
1579
1580 store_log(ps, NULL, "png_create_read_struct returned NULL (unexpected)",
1581 1 /*error*/);
1582
1583 Throw ps;
1584 }
1585
1586 store_read_set(ps, id);
1587
1588 if (ppi != NULL)
1589 *ppi = ps->piread = png_create_info_struct(ps->pread);
1590
1591 return ps->pread;
1592}
1593
1594/* The overall cleanup of a store simply calls the above then removes all the
1595 * saved files. This does not delete the store itself.
1596 */
1597static void
1598store_delete(png_store *ps)
1599{
1600 store_write_reset(ps);
1601 store_read_reset(ps);
1602 store_freefile(&ps->saved);
1603 store_image_free(ps, NULL);
1604}
1605
1606/*********************** PNG FILE MODIFICATION ON READ ************************/
1607/* Files may be modified on read. The following structure contains a complete
1608 * png_store together with extra members to handle modification and a special
1609 * read callback for libpng. To use this the 'modifications' field must be set
1610 * to a list of png_modification structures that actually perform the
1611 * modification, otherwise a png_modifier is functionally equivalent to a
1612 * png_store. There is a special read function, set_modifier_for_read, which
1613 * replaces set_store_for_read.
1614 */
1615typedef enum modifier_state
1616{
1617 modifier_start, /* Initial value */
1618 modifier_signature, /* Have a signature */
1619 modifier_IHDR /* Have an IHDR */
1620} modifier_state;
1621
1622typedef struct CIE_color
1623{
1624 /* A single CIE tristimulus value, representing the unique response of a
1625 * standard observer to a variety of light spectra. The observer recognizes
1626 * all spectra that produce this response as the same color, therefore this
1627 * is effectively a description of a color.
1628 */
1629 double X, Y, Z;
1630} CIE_color;
1631
1632static double
1633chromaticity_x(CIE_color c)
1634{
1635 return c.X / (c.X + c.Y + c.Z);
1636}
1637
1638static double
1639chromaticity_y(CIE_color c)
1640{
1641 return c.Y / (c.X + c.Y + c.Z);
1642}
1643
1644typedef struct color_encoding
1645{
1646 /* A description of an (R,G,B) encoding of color (as defined above); this
1647 * includes the actual colors of the (R,G,B) triples (1,0,0), (0,1,0) and
1648 * (0,0,1) plus an encoding value that is used to encode the linear
1649 * components R, G and B to give the actual values R^gamma, G^gamma and
1650 * B^gamma that are stored.
1651 */
1652 double gamma; /* Encoding (file) gamma of space */
1653 CIE_color red, green, blue; /* End points */
1654} color_encoding;
1655
1656static CIE_color
1657white_point(PNG_CONST color_encoding *encoding)
1658{
1659 CIE_color white;
1660
1661 white.X = encoding->red.X + encoding->green.X + encoding->blue.X;
1662 white.Y = encoding->red.Y + encoding->green.Y + encoding->blue.Y;
1663 white.Z = encoding->red.Z + encoding->green.Z + encoding->blue.Z;
1664
1665 return white;
1666}
1667
1668static void
1669normalize_color_encoding(color_encoding *encoding)
1670{
1671 PNG_CONST double whiteY = encoding->red.Y + encoding->green.Y +
1672 encoding->blue.Y;
1673
1674 if (whiteY != 1)
1675 {
1676 encoding->red.X /= whiteY;
1677 encoding->red.Y /= whiteY;
1678 encoding->red.Z /= whiteY;
1679 encoding->green.X /= whiteY;
1680 encoding->green.Y /= whiteY;
1681 encoding->green.Z /= whiteY;
1682 encoding->blue.X /= whiteY;
1683 encoding->blue.Y /= whiteY;
1684 encoding->blue.Z /= whiteY;
1685 }
1686}
1687
1688static size_t
1689safecat_color_encoding(char *buffer, size_t bufsize, size_t pos,
1690 PNG_CONST color_encoding *e, double encoding_gamma)
1691{
1692 if (e != 0)
1693 {
1694 if (encoding_gamma != 0)
1695 pos = safecat(buffer, bufsize, pos, "(");
1696 pos = safecat(buffer, bufsize, pos, "R(");
1697 pos = safecatd(buffer, bufsize, pos, e->red.X, 4);
1698 pos = safecat(buffer, bufsize, pos, ",");
1699 pos = safecatd(buffer, bufsize, pos, e->red.Y, 4);
1700 pos = safecat(buffer, bufsize, pos, ",");
1701 pos = safecatd(buffer, bufsize, pos, e->red.Z, 4);
1702 pos = safecat(buffer, bufsize, pos, "),G(");
1703 pos = safecatd(buffer, bufsize, pos, e->green.X, 4);
1704 pos = safecat(buffer, bufsize, pos, ",");
1705 pos = safecatd(buffer, bufsize, pos, e->green.Y, 4);
1706 pos = safecat(buffer, bufsize, pos, ",");
1707 pos = safecatd(buffer, bufsize, pos, e->green.Z, 4);
1708 pos = safecat(buffer, bufsize, pos, "),B(");
1709 pos = safecatd(buffer, bufsize, pos, e->blue.X, 4);
1710 pos = safecat(buffer, bufsize, pos, ",");
1711 pos = safecatd(buffer, bufsize, pos, e->blue.Y, 4);
1712 pos = safecat(buffer, bufsize, pos, ",");
1713 pos = safecatd(buffer, bufsize, pos, e->blue.Z, 4);
1714 pos = safecat(buffer, bufsize, pos, ")");
1715 if (encoding_gamma != 0)
1716 pos = safecat(buffer, bufsize, pos, ")");
1717 }
1718
1719 if (encoding_gamma != 0)
1720 {
1721 pos = safecat(buffer, bufsize, pos, "^");
1722 pos = safecatd(buffer, bufsize, pos, encoding_gamma, 5);
1723 }
1724
1725 return pos;
1726}
1727
1728typedef struct png_modifier
1729{
1730 png_store this; /* I am a png_store */
1731 struct png_modification *modifications; /* Changes to make */
1732
1733 modifier_state state; /* My state */
1734
1735 /* Information from IHDR: */
1736 png_byte bit_depth; /* From IHDR */
1737 png_byte colour_type; /* From IHDR */
1738
1739 /* While handling PLTE, IDAT and IEND these chunks may be pended to allow
1740 * other chunks to be inserted.
1741 */
1742 png_uint_32 pending_len;
1743 png_uint_32 pending_chunk;
1744
1745 /* Test values */
1746 double *gammas;
1747 unsigned int ngammas;
1748 unsigned int ngamma_tests; /* Number of gamma tests to run*/
1749 double current_gamma; /* 0 if not set */
1750 PNG_CONST color_encoding *encodings;
1751 unsigned int nencodings;
1752 PNG_CONST color_encoding *current_encoding; /* If an encoding has been set */
1753 unsigned int encoding_counter; /* For iteration */
1754 int encoding_ignored; /* Something overwrote it */
1755
1756 /* Control variables used to iterate through possible encodings, the
1757 * following must be set to 0 and tested by the function that uses the
1758 * png_modifier because the modifier only sets it to 1 (true.)
1759 */
1760 unsigned int repeat :1; /* Repeat this transform test. */
1761 unsigned int test_uses_encoding :1;
1762
1763 /* Lowest sbit to test (libpng fails for sbit < 8) */
1764 png_byte sbitlow;
1765
1766 /* Error control - these are the limits on errors accepted by the gamma tests
1767 * below.
1768 */
1769 double maxout8; /* Maximum output value error */
1770 double maxabs8; /* Absolute sample error 0..1 */
1771 double maxcalc8; /* Absolute sample error 0..1 */
1772 double maxpc8; /* Percentage sample error 0..100% */
1773 double maxout16; /* Maximum output value error */
1774 double maxabs16; /* Absolute sample error 0..1 */
1775 double maxcalc16;/* Absolute sample error 0..1 */
1776 double maxpc16; /* Percentage sample error 0..100% */
1777
1778 /* This is set by transforms that need to allow a higher limit, it is an
1779 * internal check on pngvalid to ensure that the calculated error limits are
1780 * not ridiculous; without this it is too easy to make a mistake in pngvalid
1781 * that allows any value through.
1782 */
1783 double limit; /* limit on error values, normally 4E-3 */
1784
1785 /* Log limits - values above this are logged, but not necessarily
1786 * warned.
1787 */
1788 double log8; /* Absolute error in 8 bits to log */
1789 double log16; /* Absolute error in 16 bits to log */
1790
1791 /* Logged 8 and 16 bit errors ('output' values): */
1792 double error_gray_2;
1793 double error_gray_4;
1794 double error_gray_8;
1795 double error_gray_16;
1796 double error_color_8;
1797 double error_color_16;
1798 double error_indexed;
1799
1800 /* Flags: */
1801 /* Whether to call png_read_update_info, not png_read_start_image, and how
1802 * many times to call it.
1803 */
1804 int use_update_info;
1805
1806 /* Whether or not to interlace. */
1807 int interlace_type :9; /* int, but must store '1' */
1808
1809 /* Run the standard tests? */
1810 unsigned int test_standard :1;
1811
1812 /* Run the odd-sized image and interlace read/write tests? */
1813 unsigned int test_size :1;
1814
1815 /* Run tests on reading with a combiniation of transforms, */
1816 unsigned int test_transform :1;
1817
1818 /* When to use the use_input_precision option: */
1819 unsigned int use_input_precision :1;
1820 unsigned int use_input_precision_sbit :1;
1821 unsigned int use_input_precision_16to8 :1;
1822
1823 /* If set assume that the calculation bit depth is set by the input
1824 * precision, not the output precision.
1825 */
1826 unsigned int calculations_use_input_precision :1;
1827
1828 /* If set assume that the calculations are done in 16 bits even if both input
1829 * and output are 8 bit or less.
1830 */
1831 unsigned int assume_16_bit_calculations :1;
1832
1833 /* Which gamma tests to run: */
1834 unsigned int test_gamma_threshold :1;
1835 unsigned int test_gamma_transform :1; /* main tests */
1836 unsigned int test_gamma_sbit :1;
1837 unsigned int test_gamma_scale16 :1;
1838 unsigned int test_gamma_background :1;
1839 unsigned int test_gamma_alpha_mode :1;
1840 unsigned int test_gamma_expand16 :1;
1841 unsigned int test_exhaustive :1;
1842
1843 unsigned int log :1; /* Log max error */
1844
1845 /* Buffer information, the buffer size limits the size of the chunks that can
1846 * be modified - they must fit (including header and CRC) into the buffer!
1847 */
1848 size_t flush; /* Count of bytes to flush */
1849 size_t buffer_count; /* Bytes in buffer */
1850 size_t buffer_position; /* Position in buffer */
1851 png_byte buffer[1024];
1852} png_modifier;
1853
1854/* This returns true if the test should be stopped now because it has already
1855 * failed and it is running silently.
1856 */
1857static int fail(png_modifier *pm)
1858{
1859 return !pm->log && !pm->this.verbose && (pm->this.nerrors > 0 ||
1860 (pm->this.treat_warnings_as_errors && pm->this.nwarnings > 0));
1861}
1862
1863static void
1864modifier_init(png_modifier *pm)
1865{
1866 memset(pm, 0, sizeof *pm);
1867 store_init(&pm->this);
1868 pm->modifications = NULL;
1869 pm->state = modifier_start;
1870 pm->sbitlow = 1U;
1871 pm->ngammas = 0;
1872 pm->ngamma_tests = 0;
1873 pm->gammas = 0;
1874 pm->current_gamma = 0;
1875 pm->encodings = 0;
1876 pm->nencodings = 0;
1877 pm->current_encoding = 0;
1878 pm->encoding_counter = 0;
1879 pm->encoding_ignored = 0;
1880 pm->repeat = 0;
1881 pm->test_uses_encoding = 0;
1882 pm->maxout8 = pm->maxpc8 = pm->maxabs8 = pm->maxcalc8 = 0;
1883 pm->maxout16 = pm->maxpc16 = pm->maxabs16 = pm->maxcalc16 = 0;
1884 pm->limit = 4E-3;
1885 pm->log8 = pm->log16 = 0; /* Means 'off' */
1886 pm->error_gray_2 = pm->error_gray_4 = pm->error_gray_8 = 0;
1887 pm->error_gray_16 = pm->error_color_8 = pm->error_color_16 = 0;
1888 pm->error_indexed = 0;
1889 pm->use_update_info = 0;
1890 pm->interlace_type = PNG_INTERLACE_NONE;
1891 pm->test_standard = 0;
1892 pm->test_size = 0;
1893 pm->test_transform = 0;
1894 pm->use_input_precision = 0;
1895 pm->use_input_precision_sbit = 0;
1896 pm->use_input_precision_16to8 = 0;
1897 pm->calculations_use_input_precision = 0;
1898 pm->test_gamma_threshold = 0;
1899 pm->test_gamma_transform = 0;
1900 pm->test_gamma_sbit = 0;
1901 pm->test_gamma_scale16 = 0;
1902 pm->test_gamma_background = 0;
1903 pm->test_gamma_alpha_mode = 0;
1904 pm->test_gamma_expand16 = 0;
1905 pm->test_exhaustive = 0;
1906 pm->log = 0;
1907
1908 /* Rely on the memset for all the other fields - there are no pointers */
1909}
1910
1911#ifdef PNG_READ_TRANSFORMS_SUPPORTED
1912/* If pm->calculations_use_input_precision is set then operations will happen
1913 * with only 8 bit precision unless both the input and output bit depth are 16.
1914 *
1915 * If pm->assume_16_bit_calculations is set then even 8 bit calculations use 16
1916 * bit precision. This only affects those of the following limits that pertain
1917 * to a calculation - not a digitization operation - unless the following API is
1918 * called directly.
1919 */
1920static double digitize(PNG_CONST png_modifier *pm, double value,
1921 int sample_depth, int do_round)
1922{
1923 /* 'value' is in the range 0 to 1, the result is the same value rounded to a
1924 * multiple of the digitization factor - 8 or 16 bits depending on both the
1925 * sample depth and the 'assume' setting. Digitization is normally by
1926 * rounding and 'do_round' should be 1, if it is 0 the digitized value will
1927 * be truncated.
1928 */
1929 PNG_CONST unsigned int digitization_factor =
1930 (pm->assume_16_bit_calculations || sample_depth == 16) ? 65535 : 255;
1931
1932 /* Limiting the range is done as a convenience to the caller - it's easier to
1933 * do it once here than every time at the call site.
1934 */
1935 if (value <= 0)
1936 value = 0;
1937 else if (value >= 1)
1938 value = 1;
1939
1940 value *= digitization_factor;
1941 if (do_round) value += .5;
1942 return floor(value)/digitization_factor;
1943}
1944
1945static double abserr(PNG_CONST png_modifier *pm, int in_depth, int out_depth)
1946{
1947 /* Absolute error permitted in linear values - affected by the bit depth of
1948 * the calculations.
1949 */
1950 if (pm->assume_16_bit_calculations || (out_depth == 16 && (in_depth == 16 ||
1951 !pm->calculations_use_input_precision)))
1952 return pm->maxabs16;
1953 else
1954 return pm->maxabs8;
1955}
1956
1957static double calcerr(PNG_CONST png_modifier *pm, int in_depth, int out_depth)
1958{
1959 /* Error in the linear composition arithmetic - only relevant when
1960 * composition actually happens (0 < alpha < 1).
1961 */
1962 if (pm->assume_16_bit_calculations || (out_depth == 16 && (in_depth == 16 ||
1963 !pm->calculations_use_input_precision)))
1964 return pm->maxcalc16;
1965 else
1966 return pm->maxcalc8;
1967}
1968
1969static double pcerr(PNG_CONST png_modifier *pm, int in_depth, int out_depth)
1970{
1971 /* Percentage error permitted in the linear values. Note that the specified
1972 * value is a percentage but this routine returns a simple number.
1973 */
1974 if (pm->assume_16_bit_calculations || (out_depth == 16 && (in_depth == 16 ||
1975 !pm->calculations_use_input_precision)))
1976 return pm->maxpc16 * .01;
1977 else
1978 return pm->maxpc8 * .01;
1979}
1980
1981/* Output error - the error in the encoded value. This is determined by the
1982 * digitization of the output so can be +/-0.5 in the actual output value. In
1983 * the expand_16 case with the current code in libpng the expand happens after
1984 * all the calculations are done in 8 bit arithmetic, so even though the output
1985 * depth is 16 the output error is determined by the 8 bit calculation.
1986 *
1987 * This limit is not determined by the bit depth of internal calculations.
1988 *
1989 * The specified parameter does *not* include the base .5 digitization error but
1990 * it is added here.
1991 */
1992static double outerr(PNG_CONST png_modifier *pm, int in_depth, int out_depth)
1993{
1994 /* There is a serious error in the 2 and 4 bit grayscale transform because
1995 * the gamma table value (8 bits) is simply shifted, not rounded, so the
1996 * error in 4 bit grayscale gamma is up to the value below. This is a hack
1997 * to allow pngvalid to succeed:
1998 *
1999 * TODO: fix this in libpng
2000 */
2001 if (out_depth == 2)
2002 return .73182-.5;
2003
2004 if (out_depth == 4)
2005 return .90644-.5;
2006
2007 if (out_depth == 16 && (in_depth == 16 ||
2008 !pm->calculations_use_input_precision))
2009 return pm->maxout16;
2010
2011 /* This is the case where the value was calculated at 8-bit precision then
2012 * scaled to 16 bits.
2013 */
2014 else if (out_depth == 16)
2015 return pm->maxout8 * 257;
2016
2017 else
2018 return pm->maxout8;
2019}
2020
2021/* This does the same thing as the above however it returns the value to log,
2022 * rather than raising a warning. This is useful for debugging to track down
2023 * exactly what set of parameters cause high error values.
2024 */
2025static double outlog(PNG_CONST png_modifier *pm, int in_depth, int out_depth)
2026{
2027 /* The command line parameters are either 8 bit (0..255) or 16 bit (0..65535)
2028 * and so must be adjusted for low bit depth grayscale:
2029 */
2030 if (out_depth <= 8)
2031 {
2032 if (pm->log8 == 0) /* switched off */
2033 return 256;
2034
2035 if (out_depth < 8)
2036 return pm->log8 / 255 * ((1<<out_depth)-1);
2037
2038 return pm->log8;
2039 }
2040
2041 if (out_depth == 16 && (in_depth == 16 ||
2042 !pm->calculations_use_input_precision))
2043 {
2044 if (pm->log16 == 0)
2045 return 65536;
2046
2047 return pm->log16;
2048 }
2049
2050 /* This is the case where the value was calculated at 8-bit precision then
2051 * scaled to 16 bits.
2052 */
2053 if (pm->log8 == 0)
2054 return 65536;
2055
2056 return pm->log8 * 257;
2057}
2058
2059/* This complements the above by providing the appropriate quantization for the
2060 * final value. Normally this would just be quantization to an integral value,
2061 * but in the 8 bit calculation case it's actually quantization to a multiple of
2062 * 257!
2063 */
2064static int output_quantization_factor(PNG_CONST png_modifier *pm, int in_depth,
2065 int out_depth)
2066{
2067 if (out_depth == 16 && in_depth != 16
2068 && pm->calculations_use_input_precision)
2069 return 257;
2070 else
2071 return 1;
2072}
2073
2074/* One modification structure must be provided for each chunk to be modified (in
2075 * fact more than one can be provided if multiple separate changes are desired
2076 * for a single chunk.) Modifications include adding a new chunk when a
2077 * suitable chunk does not exist.
2078 *
2079 * The caller of modify_fn will reset the CRC of the chunk and record 'modified'
2080 * or 'added' as appropriate if the modify_fn returns 1 (true). If the
2081 * modify_fn is NULL the chunk is simply removed.
2082 */
2083typedef struct png_modification
2084{
2085 struct png_modification *next;
2086 png_uint_32 chunk;
2087
2088 /* If the following is NULL all matching chunks will be removed: */
2089 int (*modify_fn)(struct png_modifier *pm,
2090 struct png_modification *me, int add);
2091
2092 /* If the following is set to PLTE, IDAT or IEND and the chunk has not been
2093 * found and modified (and there is a modify_fn) the modify_fn will be called
2094 * to add the chunk before the relevant chunk.
2095 */
2096 png_uint_32 add;
2097 unsigned int modified :1; /* Chunk was modified */
2098 unsigned int added :1; /* Chunk was added */
2099 unsigned int removed :1; /* Chunk was removed */
2100} png_modification;
2101
2102static void
2103modification_reset(png_modification *pmm)
2104{
2105 if (pmm != NULL)
2106 {
2107 pmm->modified = 0;
2108 pmm->added = 0;
2109 pmm->removed = 0;
2110 modification_reset(pmm->next);
2111 }
2112}
2113
2114static void
2115modification_init(png_modification *pmm)
2116{
2117 memset(pmm, 0, sizeof *pmm);
2118 pmm->next = NULL;
2119 pmm->chunk = 0;
2120 pmm->modify_fn = NULL;
2121 pmm->add = 0;
2122 modification_reset(pmm);
2123}
2124
2125static void
2126modifier_current_encoding(PNG_CONST png_modifier *pm, color_encoding *ce)
2127{
2128 if (pm->current_encoding != 0)
2129 *ce = *pm->current_encoding;
2130
2131 else
2132 memset(ce, 0, sizeof *ce);
2133
2134 ce->gamma = pm->current_gamma;
2135}
2136
2137static size_t
2138safecat_current_encoding(char *buffer, size_t bufsize, size_t pos,
2139 PNG_CONST png_modifier *pm)
2140{
2141 pos = safecat_color_encoding(buffer, bufsize, pos, pm->current_encoding,
2142 pm->current_gamma);
2143
2144 if (pm->encoding_ignored)
2145 pos = safecat(buffer, bufsize, pos, "[overridden]");
2146
2147 return pos;
2148}
2149
2150/* Iterate through the usefully testable color encodings. An encoding is one
2151 * of:
2152 *
2153 * 1) Nothing (no color space, no gamma).
2154 * 2) Just a gamma value from the gamma array (including 1.0)
2155 * 3) A color space from the encodings array with the corresponding gamma.
2156 * 4) The same, but with gamma 1.0 (only really useful with 16 bit calculations)
2157 *
2158 * The iterator selects these in turn, the randomizer selects one at random,
2159 * which is used depends on the setting of the 'test_exhaustive' flag. Notice
2160 * that this function changes the colour space encoding so it must only be
2161 * called on completion of the previous test. This is what 'modifier_reset'
2162 * does, below.
2163 *
2164 * After the function has been called the 'repeat' flag will still be set; the
2165 * caller of modifier_reset must reset it at the start of each run of the test!
2166 */
2167static unsigned int
2168modifier_total_encodings(PNG_CONST png_modifier *pm)
2169{
2170 return 1 + /* (1) nothing */
2171 pm->ngammas + /* (2) gamma values to test */
2172 pm->nencodings + /* (3) total number of encodings */
2173 /* The following test only works after the first time through the
2174 * png_modifier code because 'bit_depth' is set when the IHDR is read.
2175 * modifier_reset, below, preserves the setting until after it has called
2176 * the iterate function (also below.)
2177 *
2178 * For this reason do not rely on this function outside a call to
2179 * modifier_reset.
2180 */
2181 ((pm->bit_depth == 16 || pm->assume_16_bit_calculations) ?
2182 pm->nencodings : 0); /* (4) encodings with gamma == 1.0 */
2183}
2184
2185static void
2186modifier_encoding_iterate(png_modifier *pm)
2187{
2188 if (!pm->repeat && /* Else something needs the current encoding again. */
2189 pm->test_uses_encoding) /* Some transform is encoding dependent */
2190 {
2191 if (pm->test_exhaustive)
2192 {
2193 if (++pm->encoding_counter >= modifier_total_encodings(pm))
2194 pm->encoding_counter = 0; /* This will stop the repeat */
2195 }
2196
2197 else
2198 {
2199 /* Not exhaustive - choose an encoding at random; generate a number in
2200 * the range 1..(max-1), so the result is always non-zero:
2201 */
2202 if (pm->encoding_counter == 0)
2203 pm->encoding_counter = random_mod(modifier_total_encodings(pm)-1)+1;
2204 else
2205 pm->encoding_counter = 0;
2206 }
2207
2208 if (pm->encoding_counter > 0)
2209 pm->repeat = 1;
2210 }
2211
2212 else if (!pm->repeat)
2213 pm->encoding_counter = 0;
2214}
2215
2216static void
2217modifier_reset(png_modifier *pm)
2218{
2219 store_read_reset(&pm->this);
2220 pm->limit = 4E-3;
2221 pm->pending_len = pm->pending_chunk = 0;
2222 pm->flush = pm->buffer_count = pm->buffer_position = 0;
2223 pm->modifications = NULL;
2224 pm->state = modifier_start;
2225 modifier_encoding_iterate(pm);
2226 /* The following must be set in the next run. In particular
2227 * test_uses_encodings must be set in the _ini function of each transform
2228 * that looks at the encodings. (Not the 'add' function!)
2229 */
2230 pm->test_uses_encoding = 0;
2231 pm->current_gamma = 0;
2232 pm->current_encoding = 0;
2233 pm->encoding_ignored = 0;
2234 /* These only become value after IHDR is read: */
2235 pm->bit_depth = pm->colour_type = 0;
2236}
2237
2238/* The following must be called before anything else to get the encoding set up
2239 * on the modifier. In particular it must be called before the transform init
2240 * functions are called.
2241 */
2242static void
2243modifier_set_encoding(png_modifier *pm)
2244{
2245 /* Set the encoding to the one specified by the current encoding counter,
2246 * first clear out all the settings - this corresponds to an encoding_counter
2247 * of 0.
2248 */
2249 pm->current_gamma = 0;
2250 pm->current_encoding = 0;
2251 pm->encoding_ignored = 0; /* not ignored yet - happens in _ini functions. */
2252
2253 /* Now, if required, set the gamma and encoding fields. */
2254 if (pm->encoding_counter > 0)
2255 {
2256 /* The gammas[] array is an array of screen gammas, not encoding gammas,
2257 * so we need the inverse:
2258 */
2259 if (pm->encoding_counter <= pm->ngammas)
2260 pm->current_gamma = 1/pm->gammas[pm->encoding_counter-1];
2261
2262 else
2263 {
2264 unsigned int i = pm->encoding_counter - pm->ngammas;
2265
2266 if (i >= pm->nencodings)
2267 {
2268 i %= pm->nencodings;
2269 pm->current_gamma = 1; /* Linear, only in the 16 bit case */
2270 }
2271
2272 else
2273 pm->current_gamma = pm->encodings[i].gamma;
2274
2275 pm->current_encoding = pm->encodings + i;
2276 }
2277 }
2278}
2279
2280/* Enquiry functions to find out what is set. Notice that there is an implicit
2281 * assumption below that the first encoding in the list is the one for sRGB.
2282 */
2283static int
2284modifier_color_encoding_is_sRGB(PNG_CONST png_modifier *pm)
2285{
2286 return pm->current_encoding != 0 && pm->current_encoding == pm->encodings &&
2287 pm->current_encoding->gamma == pm->current_gamma;
2288}
2289
2290static int
2291modifier_color_encoding_is_set(PNG_CONST png_modifier *pm)
2292{
2293 return pm->current_gamma != 0;
2294}
2295
2296/* Convenience macros. */
2297#define CHUNK(a,b,c,d) (((a)<<24)+((b)<<16)+((c)<<8)+(d))
2298#define CHUNK_IHDR CHUNK(73,72,68,82)
2299#define CHUNK_PLTE CHUNK(80,76,84,69)
2300#define CHUNK_IDAT CHUNK(73,68,65,84)
2301#define CHUNK_IEND CHUNK(73,69,78,68)
2302#define CHUNK_cHRM CHUNK(99,72,82,77)
2303#define CHUNK_gAMA CHUNK(103,65,77,65)
2304#define CHUNK_sBIT CHUNK(115,66,73,84)
2305#define CHUNK_sRGB CHUNK(115,82,71,66)
2306
2307/* The guts of modification are performed during a read. */
2308static void
2309modifier_crc(png_bytep buffer)
2310{
2311 /* Recalculate the chunk CRC - a complete chunk must be in
2312 * the buffer, at the start.
2313 */
2314 uInt datalen = png_get_uint_32(buffer);
2315 uLong crc = crc32(0, buffer+4, datalen+4);
2316 /* The cast to png_uint_32 is safe because a crc32 is always a 32 bit value.
2317 */
2318 png_save_uint_32(buffer+datalen+8, (png_uint_32)crc);
2319}
2320
2321static void
2322modifier_setbuffer(png_modifier *pm)
2323{
2324 modifier_crc(pm->buffer);
2325 pm->buffer_count = png_get_uint_32(pm->buffer)+12;
2326 pm->buffer_position = 0;
2327}
2328
2329/* Separate the callback into the actual implementation (which is passed the
2330 * png_modifier explicitly) and the callback, which gets the modifier from the
2331 * png_struct.
2332 */
2333static void
2334modifier_read_imp(png_modifier *pm, png_bytep pb, png_size_t st)
2335{
2336 while (st > 0)
2337 {
2338 size_t cb;
2339 png_uint_32 len, chunk;
2340 png_modification *mod;
2341
2342 if (pm->buffer_position >= pm->buffer_count) switch (pm->state)
2343 {
2344 static png_byte sign[8] = { 137, 80, 78, 71, 13, 10, 26, 10 };
2345 case modifier_start:
2346 store_read_imp(&pm->this, pm->buffer, 8); /* size of signature. */
2347 pm->buffer_count = 8;
2348 pm->buffer_position = 0;
2349
2350 if (memcmp(pm->buffer, sign, 8) != 0)
2351 png_error(pm->this.pread, "invalid PNG file signature");
2352 pm->state = modifier_signature;
2353 break;
2354
2355 case modifier_signature:
2356 store_read_imp(&pm->this, pm->buffer, 13+12); /* size of IHDR */
2357 pm->buffer_count = 13+12;
2358 pm->buffer_position = 0;
2359
2360 if (png_get_uint_32(pm->buffer) != 13 ||
2361 png_get_uint_32(pm->buffer+4) != CHUNK_IHDR)
2362 png_error(pm->this.pread, "invalid IHDR");
2363
2364 /* Check the list of modifiers for modifications to the IHDR. */
2365 mod = pm->modifications;
2366 while (mod != NULL)
2367 {
2368 if (mod->chunk == CHUNK_IHDR && mod->modify_fn &&
2369 (*mod->modify_fn)(pm, mod, 0))
2370 {
2371 mod->modified = 1;
2372 modifier_setbuffer(pm);
2373 }
2374
2375 /* Ignore removal or add if IHDR! */
2376 mod = mod->next;
2377 }
2378
2379 /* Cache information from the IHDR (the modified one.) */
2380 pm->bit_depth = pm->buffer[8+8];
2381 pm->colour_type = pm->buffer[8+8+1];
2382
2383 pm->state = modifier_IHDR;
2384 pm->flush = 0;
2385 break;
2386
2387 case modifier_IHDR:
2388 default:
2389 /* Read a new chunk and process it until we see PLTE, IDAT or
2390 * IEND. 'flush' indicates that there is still some data to
2391 * output from the preceding chunk.
2392 */
2393 if ((cb = pm->flush) > 0)
2394 {
2395 if (cb > st) cb = st;
2396 pm->flush -= cb;
2397 store_read_imp(&pm->this, pb, cb);
2398 pb += cb;
2399 st -= cb;
2400 if (st == 0) return;
2401 }
2402
2403 /* No more bytes to flush, read a header, or handle a pending
2404 * chunk.
2405 */
2406 if (pm->pending_chunk != 0)
2407 {
2408 png_save_uint_32(pm->buffer, pm->pending_len);
2409 png_save_uint_32(pm->buffer+4, pm->pending_chunk);
2410 pm->pending_len = 0;
2411 pm->pending_chunk = 0;
2412 }
2413 else
2414 store_read_imp(&pm->this, pm->buffer, 8);
2415
2416 pm->buffer_count = 8;
2417 pm->buffer_position = 0;
2418
2419 /* Check for something to modify or a terminator chunk. */
2420 len = png_get_uint_32(pm->buffer);
2421 chunk = png_get_uint_32(pm->buffer+4);
2422
2423 /* Terminators first, they may have to be delayed for added
2424 * chunks
2425 */
2426 if (chunk == CHUNK_PLTE || chunk == CHUNK_IDAT ||
2427 chunk == CHUNK_IEND)
2428 {
2429 mod = pm->modifications;
2430
2431 while (mod != NULL)
2432 {
2433 if ((mod->add == chunk ||
2434 (mod->add == CHUNK_PLTE && chunk == CHUNK_IDAT)) &&
2435 mod->modify_fn != NULL && !mod->modified && !mod->added)
2436 {
2437 /* Regardless of what the modify function does do not run
2438 * this again.
2439 */
2440 mod->added = 1;
2441
2442 if ((*mod->modify_fn)(pm, mod, 1 /*add*/))
2443 {
2444 /* Reset the CRC on a new chunk */
2445 if (pm->buffer_count > 0)
2446 modifier_setbuffer(pm);
2447
2448 else
2449 {
2450 pm->buffer_position = 0;
2451 mod->removed = 1;
2452 }
2453
2454 /* The buffer has been filled with something (we assume)
2455 * so output this. Pend the current chunk.
2456 */
2457 pm->pending_len = len;
2458 pm->pending_chunk = chunk;
2459 break; /* out of while */
2460 }
2461 }
2462
2463 mod = mod->next;
2464 }
2465
2466 /* Don't do any further processing if the buffer was modified -
2467 * otherwise the code will end up modifying a chunk that was
2468 * just added.
2469 */
2470 if (mod != NULL)
2471 break; /* out of switch */
2472 }
2473
2474 /* If we get to here then this chunk may need to be modified. To
2475 * do this it must be less than 1024 bytes in total size, otherwise
2476 * it just gets flushed.
2477 */
2478 if (len+12 <= sizeof pm->buffer)
2479 {
2480 store_read_imp(&pm->this, pm->buffer+pm->buffer_count,
2481 len+12-pm->buffer_count);
2482 pm->buffer_count = len+12;
2483
2484 /* Check for a modification, else leave it be. */
2485 mod = pm->modifications;
2486 while (mod != NULL)
2487 {
2488 if (mod->chunk == chunk)
2489 {
2490 if (mod->modify_fn == NULL)
2491 {
2492 /* Remove this chunk */
2493 pm->buffer_count = pm->buffer_position = 0;
2494 mod->removed = 1;
2495 break; /* Terminate the while loop */
2496 }
2497
2498 else if ((*mod->modify_fn)(pm, mod, 0))
2499 {
2500 mod->modified = 1;
2501 /* The chunk may have been removed: */
2502 if (pm->buffer_count == 0)
2503 {
2504 pm->buffer_position = 0;
2505 break;
2506 }
2507 modifier_setbuffer(pm);
2508 }
2509 }
2510
2511 mod = mod->next;
2512 }
2513 }
2514
2515 else
2516 pm->flush = len+12 - pm->buffer_count; /* data + crc */
2517
2518 /* Take the data from the buffer (if there is any). */
2519 break;
2520 }
2521
2522 /* Here to read from the modifier buffer (not directly from
2523 * the store, as in the flush case above.)
2524 */
2525 cb = pm->buffer_count - pm->buffer_position;
2526
2527 if (cb > st)
2528 cb = st;
2529
2530 memcpy(pb, pm->buffer + pm->buffer_position, cb);
2531 st -= cb;
2532 pb += cb;
2533 pm->buffer_position += cb;
2534 }
2535}
2536
2537/* The callback: */
2538static void
2539modifier_read(png_structp pp, png_bytep pb, png_size_t st)
2540{
2541 png_modifier *pm = voidcast(png_modifier*, png_get_io_ptr(pp));
2542
2543 if (pm == NULL || pm->this.pread != pp)
2544 png_error(pp, "bad modifier_read call");
2545
2546 modifier_read_imp(pm, pb, st);
2547}
2548
2549/* Like store_progressive_read but the data is getting changed as we go so we
2550 * need a local buffer.
2551 */
2552static void
2553modifier_progressive_read(png_modifier *pm, png_structp pp, png_infop pi)
2554{
2555 if (pm->this.pread != pp || pm->this.current == NULL ||
2556 pm->this.next == NULL)
2557 png_error(pp, "store state damaged (progressive)");
2558
2559 /* This is another Horowitz and Hill random noise generator. In this case
2560 * the aim is to stress the progressive reader with truly horrible variable
2561 * buffer sizes in the range 1..500, so a sequence of 9 bit random numbers
2562 * is generated. We could probably just count from 1 to 32767 and get as
2563 * good a result.
2564 */
2565 for (;;)
2566 {
2567 static png_uint_32 noise = 1;
2568 png_size_t cb, cbAvail;
2569 png_byte buffer[512];
2570
2571 /* Generate 15 more bits of stuff: */
2572 noise = (noise << 9) | ((noise ^ (noise >> (9-5))) & 0x1ff);
2573 cb = noise & 0x1ff;
2574
2575 /* Check that this number of bytes are available (in the current buffer.)
2576 * (This doesn't quite work - the modifier might delete a chunk; unlikely
2577 * but possible, it doesn't happen at present because the modifier only
2578 * adds chunks to standard images.)
2579 */
2580 cbAvail = store_read_buffer_avail(&pm->this);
2581 if (pm->buffer_count > pm->buffer_position)
2582 cbAvail += pm->buffer_count - pm->buffer_position;
2583
2584 if (cb > cbAvail)
2585 {
2586 /* Check for EOF: */
2587 if (cbAvail == 0)
2588 break;
2589
2590 cb = cbAvail;
2591 }
2592
2593 modifier_read_imp(pm, buffer, cb);
2594 png_process_data(pp, pi, buffer, cb);
2595 }
2596
2597 /* Check the invariants at the end (if this fails it's a problem in this
2598 * file!)
2599 */
2600 if (pm->buffer_count > pm->buffer_position ||
2601 pm->this.next != &pm->this.current->data ||
2602 pm->this.readpos < pm->this.current->datacount)
2603 png_error(pp, "progressive read implementation error");
2604}
2605
2606/* Set up a modifier. */
2607static png_structp
2608set_modifier_for_read(png_modifier *pm, png_infopp ppi, png_uint_32 id,
2609 PNG_CONST char *name)
2610{
2611 /* Do this first so that the modifier fields are cleared even if an error
2612 * happens allocating the png_struct. No allocation is done here so no
2613 * cleanup is required.
2614 */
2615 pm->state = modifier_start;
2616 pm->bit_depth = 0;
2617 pm->colour_type = 255;
2618
2619 pm->pending_len = 0;
2620 pm->pending_chunk = 0;
2621 pm->flush = 0;
2622 pm->buffer_count = 0;
2623 pm->buffer_position = 0;
2624
2625 return set_store_for_read(&pm->this, ppi, id, name);
2626}
2627
2628
2629/******************************** MODIFICATIONS *******************************/
2630/* Standard modifications to add chunks. These do not require the _SUPPORTED
2631 * macros because the chunks can be there regardless of whether this specific
2632 * libpng supports them.
2633 */
2634typedef struct gama_modification
2635{
2636 png_modification this;
2637 png_fixed_point gamma;
2638} gama_modification;
2639
2640static int
2641gama_modify(png_modifier *pm, png_modification *me, int add)
2642{
2643 UNUSED(add)
2644 /* This simply dumps the given gamma value into the buffer. */
2645 png_save_uint_32(pm->buffer, 4);
2646 png_save_uint_32(pm->buffer+4, CHUNK_gAMA);
2647 png_save_uint_32(pm->buffer+8, ((gama_modification*)me)->gamma);
2648 return 1;
2649}
2650
2651static void
2652gama_modification_init(gama_modification *me, png_modifier *pm, double gammad)
2653{
2654 double g;
2655
2656 modification_init(&me->this);
2657 me->this.chunk = CHUNK_gAMA;
2658 me->this.modify_fn = gama_modify;
2659 me->this.add = CHUNK_PLTE;
2660 g = fix(gammad);
2661 me->gamma = (png_fixed_point)g;
2662 me->this.next = pm->modifications;
2663 pm->modifications = &me->this;
2664}
2665
2666typedef struct chrm_modification
2667{
2668 png_modification this;
2669 PNG_CONST color_encoding *encoding;
2670 png_fixed_point wx, wy, rx, ry, gx, gy, bx, by;
2671} chrm_modification;
2672
2673static int
2674chrm_modify(png_modifier *pm, png_modification *me, int add)
2675{
2676 UNUSED(add)
2677 /* As with gAMA this just adds the required cHRM chunk to the buffer. */
2678 png_save_uint_32(pm->buffer , 32);
2679 png_save_uint_32(pm->buffer+ 4, CHUNK_cHRM);
2680 png_save_uint_32(pm->buffer+ 8, ((chrm_modification*)me)->wx);
2681 png_save_uint_32(pm->buffer+12, ((chrm_modification*)me)->wy);
2682 png_save_uint_32(pm->buffer+16, ((chrm_modification*)me)->rx);
2683 png_save_uint_32(pm->buffer+20, ((chrm_modification*)me)->ry);
2684 png_save_uint_32(pm->buffer+24, ((chrm_modification*)me)->gx);
2685 png_save_uint_32(pm->buffer+28, ((chrm_modification*)me)->gy);
2686 png_save_uint_32(pm->buffer+32, ((chrm_modification*)me)->bx);
2687 png_save_uint_32(pm->buffer+36, ((chrm_modification*)me)->by);
2688 return 1;
2689}
2690
2691static void
2692chrm_modification_init(chrm_modification *me, png_modifier *pm,
2693 PNG_CONST color_encoding *encoding)
2694{
2695 CIE_color white = white_point(encoding);
2696
2697 /* Original end points: */
2698 me->encoding = encoding;
2699
2700 /* Chromaticities (in fixed point): */
2701 me->wx = fix(chromaticity_x(white));
2702 me->wy = fix(chromaticity_y(white));
2703
2704 me->rx = fix(chromaticity_x(encoding->red));
2705 me->ry = fix(chromaticity_y(encoding->red));
2706 me->gx = fix(chromaticity_x(encoding->green));
2707 me->gy = fix(chromaticity_y(encoding->green));
2708 me->bx = fix(chromaticity_x(encoding->blue));
2709 me->by = fix(chromaticity_y(encoding->blue));
2710
2711 modification_init(&me->this);
2712 me->this.chunk = CHUNK_cHRM;
2713 me->this.modify_fn = chrm_modify;
2714 me->this.add = CHUNK_PLTE;
2715 me->this.next = pm->modifications;
2716 pm->modifications = &me->this;
2717}
2718
2719typedef struct srgb_modification
2720{
2721 png_modification this;
2722 png_byte intent;
2723} srgb_modification;
2724
2725static int
2726srgb_modify(png_modifier *pm, png_modification *me, int add)
2727{
2728 UNUSED(add)
2729 /* As above, ignore add and just make a new chunk */
2730 png_save_uint_32(pm->buffer, 1);
2731 png_save_uint_32(pm->buffer+4, CHUNK_sRGB);
2732 pm->buffer[8] = ((srgb_modification*)me)->intent;
2733 return 1;
2734}
2735
2736static void
2737srgb_modification_init(srgb_modification *me, png_modifier *pm, png_byte intent)
2738{
2739 modification_init(&me->this);
2740 me->this.chunk = CHUNK_sBIT;
2741
2742 if (intent <= 3) /* if valid, else *delete* sRGB chunks */
2743 {
2744 me->this.modify_fn = srgb_modify;
2745 me->this.add = CHUNK_PLTE;
2746 me->intent = intent;
2747 }
2748
2749 else
2750 {
2751 me->this.modify_fn = 0;
2752 me->this.add = 0;
2753 me->intent = 0;
2754 }
2755
2756 me->this.next = pm->modifications;
2757 pm->modifications = &me->this;
2758}
2759
2760typedef struct sbit_modification
2761{
2762 png_modification this;
2763 png_byte sbit;
2764} sbit_modification;
2765
2766static int
2767sbit_modify(png_modifier *pm, png_modification *me, int add)
2768{
2769 png_byte sbit = ((sbit_modification*)me)->sbit;
2770 if (pm->bit_depth > sbit)
2771 {
2772 int cb = 0;
2773 switch (pm->colour_type)
2774 {
2775 case 0:
2776 cb = 1;
2777 break;
2778
2779 case 2:
2780 case 3:
2781 cb = 3;
2782 break;
2783
2784 case 4:
2785 cb = 2;
2786 break;
2787
2788 case 6:
2789 cb = 4;
2790 break;
2791
2792 default:
2793 png_error(pm->this.pread,
2794 "unexpected colour type in sBIT modification");
2795 }
2796
2797 png_save_uint_32(pm->buffer, cb);
2798 png_save_uint_32(pm->buffer+4, CHUNK_sBIT);
2799
2800 while (cb > 0)
2801 (pm->buffer+8)[--cb] = sbit;
2802
2803 return 1;
2804 }
2805 else if (!add)
2806 {
2807 /* Remove the sBIT chunk */
2808 pm->buffer_count = pm->buffer_position = 0;
2809 return 1;
2810 }
2811 else
2812 return 0; /* do nothing */
2813}
2814
2815static void
2816sbit_modification_init(sbit_modification *me, png_modifier *pm, png_byte sbit)
2817{
2818 modification_init(&me->this);
2819 me->this.chunk = CHUNK_sBIT;
2820 me->this.modify_fn = sbit_modify;
2821 me->this.add = CHUNK_PLTE;
2822 me->sbit = sbit;
2823 me->this.next = pm->modifications;
2824 pm->modifications = &me->this;
2825}
2826#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
2827
2828/***************************** STANDARD PNG FILES *****************************/
2829/* Standard files - write and save standard files. */
2830/* There are two basic forms of standard images. Those which attempt to have
2831 * all the possible pixel values (not possible for 16bpp images, but a range of
2832 * values are produced) and those which have a range of image sizes. The former
2833 * are used for testing transforms, in particular gamma correction and bit
2834 * reduction and increase. The latter are reserved for testing the behavior of
2835 * libpng with respect to 'odd' image sizes - particularly small images where
2836 * rows become 1 byte and interlace passes disappear.
2837 *
2838 * The first, most useful, set are the 'transform' images, the second set of
2839 * small images are the 'size' images.
2840 *
2841 * The transform files are constructed with rows which fit into a 1024 byte row
2842 * buffer. This makes allocation easier below. Further regardless of the file
2843 * format every row has 128 pixels (giving 1024 bytes for 64bpp formats).
2844 *
2845 * Files are stored with no gAMA or sBIT chunks, with a PLTE only when needed
2846 * and with an ID derived from the colour type, bit depth and interlace type
2847 * as above (FILEID). The width (128) and height (variable) are not stored in
2848 * the FILEID - instead the fields are set to 0, indicating a transform file.
2849 *
2850 * The size files ar constructed with rows a maximum of 128 bytes wide, allowing
2851 * a maximum width of 16 pixels (for the 64bpp case.) They also have a maximum
2852 * height of 16 rows. The width and height are stored in the FILEID and, being
2853 * non-zero, indicate a size file.
2854 *
2855 * For palette image (colour type 3) multiple transform images are stored with
2856 * the same bit depth to allow testing of more colour combinations -
2857 * particularly important for testing the gamma code because libpng uses a
2858 * different code path for palette images. For size images a single palette is
2859 * used.
2860 */
2861
2862/* Make a 'standard' palette. Because there are only 256 entries in a palette
2863 * (maximum) this actually makes a random palette in the hope that enough tests
2864 * will catch enough errors. (Note that the same palette isn't produced every
2865 * time for the same test - it depends on what previous tests have been run -
2866 * but a given set of arguments to pngvalid will always produce the same palette
2867 * at the same test! This is why pseudo-random number generators are useful for
2868 * testing.)
2869 *
2870 * The store must be open for write when this is called, otherwise an internal
2871 * error will occur. This routine contains its own magic number seed, so the
2872 * palettes generated don't change if there are intervening errors (changing the
2873 * calls to the store_mark seed.)
2874 */
2875static store_palette_entry *
2876make_standard_palette(png_store* ps, int npalette, int do_tRNS)
2877{
2878 static png_uint_32 palette_seed[2] = { 0x87654321, 9 };
2879
2880 int i = 0;
2881 png_byte values[256][4];
2882
2883 /* Always put in black and white plus the six primary and secondary colors.
2884 */
2885 for (; i<8; ++i)
2886 {
2887 values[i][1] = (i&1) ? 255 : 0;
2888 values[i][2] = (i&2) ? 255 : 0;
2889 values[i][3] = (i&4) ? 255 : 0;
2890 }
2891
2892 /* Then add 62 grays (one quarter of the remaining 256 slots). */
2893 {
2894 int j = 0;
2895 png_byte random_bytes[4];
2896 png_byte need[256];
2897
2898 need[0] = 0; /*got black*/
2899 memset(need+1, 1, (sizeof need)-2); /*need these*/
2900 need[255] = 0; /*but not white*/
2901
2902 while (i<70)
2903 {
2904 png_byte b;
2905
2906 if (j==0)
2907 {
2908 make_four_random_bytes(palette_seed, random_bytes);
2909 j = 4;
2910 }
2911
2912 b = random_bytes[--j];
2913 if (need[b])
2914 {
2915 values[i][1] = b;
2916 values[i][2] = b;
2917 values[i++][3] = b;
2918 }
2919 }
2920 }
2921
2922 /* Finally add 192 colors at random - don't worry about matches to things we
2923 * already have, chance is less than 1/65536. Don't worry about grays,
2924 * chance is the same, so we get a duplicate or extra gray less than 1 time
2925 * in 170.
2926 */
2927 for (; i<256; ++i)
2928 make_four_random_bytes(palette_seed, values[i]);
2929
2930 /* Fill in the alpha values in the first byte. Just use all possible values
2931 * (0..255) in an apparently random order:
2932 */
2933 {
2934 store_palette_entry *palette;
2935 png_byte selector[4];
2936
2937 make_four_random_bytes(palette_seed, selector);
2938
2939 if (do_tRNS)
2940 for (i=0; i<256; ++i)
2941 values[i][0] = (png_byte)(i ^ selector[0]);
2942
2943 else
2944 for (i=0; i<256; ++i)
2945 values[i][0] = 255; /* no transparency/tRNS chunk */
2946
2947 /* 'values' contains 256 ARGB values, but we only need 'npalette'.
2948 * 'npalette' will always be a power of 2: 2, 4, 16 or 256. In the low
2949 * bit depth cases select colors at random, else it is difficult to have
2950 * a set of low bit depth palette test with any chance of a reasonable
2951 * range of colors. Do this by randomly permuting values into the low
2952 * 'npalette' entries using an XOR mask generated here. This also
2953 * permutes the npalette == 256 case in a potentially useful way (there is
2954 * no relationship between palette index and the color value therein!)
2955 */
2956 palette = store_write_palette(ps, npalette);
2957
2958 for (i=0; i<npalette; ++i)
2959 {
2960 palette[i].alpha = values[i ^ selector[1]][0];
2961 palette[i].red = values[i ^ selector[1]][1];
2962 palette[i].green = values[i ^ selector[1]][2];
2963 palette[i].blue = values[i ^ selector[1]][3];
2964 }
2965
2966 return palette;
2967 }
2968}
2969
2970/* Initialize a standard palette on a write stream. The 'do_tRNS' argument
2971 * indicates whether or not to also set the tRNS chunk.
2972 */
2973static void
2974init_standard_palette(png_store *ps, png_structp pp, png_infop pi, int npalette,
2975 int do_tRNS)
2976{
2977 store_palette_entry *ppal = make_standard_palette(ps, npalette, do_tRNS);
2978
2979 {
2980 int i;
2981 png_color palette[256];
2982
2983 /* Set all entries to detect overread errors. */
2984 for (i=0; i<npalette; ++i)
2985 {
2986 palette[i].red = ppal[i].red;
2987 palette[i].green = ppal[i].green;
2988 palette[i].blue = ppal[i].blue;
2989 }
2990
2991 /* Just in case fill in the rest with detectable values: */
2992 for (; i<256; ++i)
2993 palette[i].red = palette[i].green = palette[i].blue = 42;
2994
2995 png_set_PLTE(pp, pi, palette, npalette);
2996 }
2997
2998 if (do_tRNS)
2999 {
3000 int i, j;
3001 png_byte tRNS[256];
3002
3003 /* Set all the entries, but skip trailing opaque entries */
3004 for (i=j=0; i<npalette; ++i)
3005 if ((tRNS[i] = ppal[i].alpha) < 255)
3006 j = i+1;
3007
3008 /* Fill in the remainder with a detectable value: */
3009 for (; i<256; ++i)
3010 tRNS[i] = 24;
3011
3012 if (j > 0)
3013 png_set_tRNS(pp, pi, tRNS, j, 0/*color*/);
3014 }
3015}
3016
3017/* The number of passes is related to the interlace type. There was no libpng
3018 * API to determine this prior to 1.5, so we need an inquiry function:
3019 */
3020static int
3021npasses_from_interlace_type(png_structp pp, int interlace_type)
3022{
3023 switch (interlace_type)
3024 {
3025 default:
3026 png_error(pp, "invalid interlace type");
3027
3028 case PNG_INTERLACE_NONE:
3029 return 1;
3030
3031 case PNG_INTERLACE_ADAM7:
3032 return PNG_INTERLACE_ADAM7_PASSES;
3033 }
3034}
3035
3036static unsigned int
3037bit_size(png_structp pp, png_byte colour_type, png_byte bit_depth)
3038{
3039 switch (colour_type)
3040 {
3041 default: png_error(pp, "invalid color type");
3042
3043 case 0: return bit_depth;
3044
3045 case 2: return 3*bit_depth;
3046
3047 case 3: return bit_depth;
3048
3049 case 4: return 2*bit_depth;
3050
3051 case 6: return 4*bit_depth;
3052 }
3053}
3054
3055#define TRANSFORM_WIDTH 128U
3056#define TRANSFORM_ROWMAX (TRANSFORM_WIDTH*8U)
3057#define SIZE_ROWMAX (16*8U) /* 16 pixels, max 8 bytes each - 128 bytes */
3058#define STANDARD_ROWMAX TRANSFORM_ROWMAX /* The larger of the two */
3059#define SIZE_HEIGHTMAX 16 /* Maximum range of size images */
3060
3061static size_t
3062transform_rowsize(png_structp pp, png_byte colour_type, png_byte bit_depth)
3063{
3064 return (TRANSFORM_WIDTH * bit_size(pp, colour_type, bit_depth)) / 8;
3065}
3066
3067/* transform_width(pp, colour_type, bit_depth) current returns the same number
3068 * every time, so just use a macro:
3069 */
3070#define transform_width(pp, colour_type, bit_depth) TRANSFORM_WIDTH
3071
3072static png_uint_32
3073transform_height(png_structp pp, png_byte colour_type, png_byte bit_depth)
3074{
3075 switch (bit_size(pp, colour_type, bit_depth))
3076 {
3077 case 1:
3078 case 2:
3079 case 4:
3080 return 1; /* Total of 128 pixels */
3081
3082 case 8:
3083 return 2; /* Total of 256 pixels/bytes */
3084
3085 case 16:
3086 return 512; /* Total of 65536 pixels */
3087
3088 case 24:
3089 case 32:
3090 return 512; /* 65536 pixels */
3091
3092 case 48:
3093 case 64:
3094 return 2048;/* 4 x 65536 pixels. */
3095# define TRANSFORM_HEIGHTMAX 2048
3096
3097 default:
3098 return 0; /* Error, will be caught later */
3099 }
3100}
3101
3102/* The following can only be defined here, now we have the definitions
3103 * of the transform image sizes.
3104 */
3105static png_uint_32
3106standard_width(png_structp pp, png_uint_32 id)
3107{
3108 png_uint_32 width = WIDTH_FROM_ID(id);
3109 UNUSED(pp)
3110
3111 if (width == 0)
3112 width = transform_width(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
3113
3114 return width;
3115}
3116
3117static png_uint_32
3118standard_height(png_structp pp, png_uint_32 id)
3119{
3120 png_uint_32 height = HEIGHT_FROM_ID(id);
3121
3122 if (height == 0)
3123 height = transform_height(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
3124
3125 return height;
3126}
3127
3128static png_uint_32
3129standard_rowsize(png_structp pp, png_uint_32 id)
3130{
3131 png_uint_32 width = standard_width(pp, id);
3132
3133 /* This won't overflow: */
3134 width *= bit_size(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
3135 return (width + 7) / 8;
3136}
3137
3138static void
3139transform_row(png_structp pp, png_byte buffer[TRANSFORM_ROWMAX],
3140 png_byte colour_type, png_byte bit_depth, png_uint_32 y)
3141{
3142 png_uint_32 v = y << 7;
3143 png_uint_32 i = 0;
3144
3145 switch (bit_size(pp, colour_type, bit_depth))
3146 {
3147 case 1:
3148 while (i<128/8) buffer[i] = v & 0xff, v += 17, ++i;
3149 return;
3150
3151 case 2:
3152 while (i<128/4) buffer[i] = v & 0xff, v += 33, ++i;
3153 return;
3154
3155 case 4:
3156 while (i<128/2) buffer[i] = v & 0xff, v += 65, ++i;
3157 return;
3158
3159 case 8:
3160 /* 256 bytes total, 128 bytes in each row set as follows: */
3161 while (i<128) buffer[i] = v & 0xff, ++v, ++i;
3162 return;
3163
3164 case 16:
3165 /* Generate all 65536 pixel values in order, which includes the 8 bit
3166 * GA case as well as the 16 bit G case.
3167 */
3168 while (i<128)
3169 buffer[2*i] = (v>>8) & 0xff, buffer[2*i+1] = v & 0xff, ++v, ++i;
3170
3171 return;
3172
3173 case 24:
3174 /* 65535 pixels, but rotate the values. */
3175 while (i<128)
3176 {
3177 /* Three bytes per pixel, r, g, b, make b by r^g */
3178 buffer[3*i+0] = (v >> 8) & 0xff;
3179 buffer[3*i+1] = v & 0xff;
3180 buffer[3*i+2] = ((v >> 8) ^ v) & 0xff;
3181 ++v;
3182 ++i;
3183 }
3184
3185 return;
3186
3187 case 32:
3188 /* 65535 pixels, r, g, b, a; just replicate */
3189 while (i<128)
3190 {
3191 buffer[4*i+0] = (v >> 8) & 0xff;
3192 buffer[4*i+1] = v & 0xff;
3193 buffer[4*i+2] = (v >> 8) & 0xff;
3194 buffer[4*i+3] = v & 0xff;
3195 ++v;
3196 ++i;
3197 }
3198
3199 return;
3200
3201 case 48:
3202 /* y is maximum 2047, giving 4x65536 pixels, make 'r' increase by 1 at
3203 * each pixel, g increase by 257 (0x101) and 'b' by 0x1111:
3204 */
3205 while (i<128)
3206 {
3207 png_uint_32 t = v++;
3208 buffer[6*i+0] = (t >> 8) & 0xff;
3209 buffer[6*i+1] = t & 0xff;
3210 t *= 257;
3211 buffer[6*i+2] = (t >> 8) & 0xff;
3212 buffer[6*i+3] = t & 0xff;
3213 t *= 17;
3214 buffer[6*i+4] = (t >> 8) & 0xff;
3215 buffer[6*i+5] = t & 0xff;
3216 ++i;
3217 }
3218
3219 return;
3220
3221 case 64:
3222 /* As above in the 32 bit case. */
3223 while (i<128)
3224 {
3225 png_uint_32 t = v++;
3226 buffer[8*i+0] = (t >> 8) & 0xff;
3227 buffer[8*i+1] = t & 0xff;
3228 buffer[8*i+4] = (t >> 8) & 0xff;
3229 buffer[8*i+5] = t & 0xff;
3230 t *= 257;
3231 buffer[8*i+2] = (t >> 8) & 0xff;
3232 buffer[8*i+3] = t & 0xff;
3233 buffer[8*i+6] = (t >> 8) & 0xff;
3234 buffer[8*i+7] = t & 0xff;
3235 ++i;
3236 }
3237 return;
3238
3239 default:
3240 break;
3241 }
3242
3243 png_error(pp, "internal error");
3244}
3245
3246/* This is just to do the right cast - could be changed to a function to check
3247 * 'bd' but there isn't much point.
3248 */
3249#define DEPTH(bd) ((png_byte)(1U << (bd)))
3250
3251/* Make a standardized image given a an image colour type, bit depth and
3252 * interlace type. The standard images have a very restricted range of
3253 * rows and heights and are used for testing transforms rather than image
3254 * layout details. See make_size_images below for a way to make images
3255 * that test odd sizes along with the libpng interlace handling.
3256 */
3257static void
3258make_transform_image(png_store* PNG_CONST ps, png_byte PNG_CONST colour_type,
3259 png_byte PNG_CONST bit_depth, int palette_number, int interlace_type,
3260 png_const_charp name)
3261{
3262 context(ps, fault);
3263
3264 Try
3265 {
3266 png_infop pi;
3267 png_structp pp = set_store_for_write(ps, &pi, name);
3268 png_uint_32 h;
3269
3270 /* In the event of a problem return control to the Catch statement below
3271 * to do the clean up - it is not possible to 'return' directly from a Try
3272 * block.
3273 */
3274 if (pp == NULL)
3275 Throw ps;
3276
3277 h = transform_height(pp, colour_type, bit_depth);
3278
3279 png_set_IHDR(pp, pi, transform_width(pp, colour_type, bit_depth), h,
3280 bit_depth, colour_type, interlace_type,
3281 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
3282
3283#ifdef PNG_TEXT_SUPPORTED
3284 {
3285 static char key[] = "image name"; /* must be writeable */
3286 size_t pos;
3287 png_text text;
3288 char copy[FILE_NAME_SIZE];
3289
3290 /* Use a compressed text string to test the correct interaction of text
3291 * compression and IDAT compression.
3292 */
3293 text.compression = PNG_TEXT_COMPRESSION_zTXt;
3294 text.key = key;
3295 /* Yuck: the text must be writable! */
3296 pos = safecat(copy, sizeof copy, 0, ps->wname);
3297 text.text = copy;
3298 text.text_length = pos;
3299 text.itxt_length = 0;
3300 text.lang = 0;
3301 text.lang_key = 0;
3302
3303 png_set_text(pp, pi, &text, 1);
3304 }
3305#endif
3306
3307 if (colour_type == 3) /* palette */
3308 init_standard_palette(ps, pp, pi, 1U << bit_depth, 1/*do tRNS*/);
3309
3310 png_write_info(pp, pi);
3311
3312 if (png_get_rowbytes(pp, pi) !=
3313 transform_rowsize(pp, colour_type, bit_depth))
3314 png_error(pp, "row size incorrect");
3315
3316 else
3317 {
3318 /* Somewhat confusingly this must be called *after* png_write_info
3319 * because if it is called before, the information in *pp has not been
3320 * updated to reflect the interlaced image.
3321 */
3322 int npasses = png_set_interlace_handling(pp);
3323 int pass;
3324
3325 if (npasses != npasses_from_interlace_type(pp, interlace_type))
3326 png_error(pp, "write: png_set_interlace_handling failed");
3327
3328 for (pass=0; pass<npasses; ++pass)
3329 {
3330 png_uint_32 y;
3331
3332 for (y=0; y<h; ++y)
3333 {
3334 png_byte buffer[TRANSFORM_ROWMAX];
3335
3336 transform_row(pp, buffer, colour_type, bit_depth, y);
3337 png_write_row(pp, buffer);
3338 }
3339 }
3340 }
3341
3342#ifdef PNG_TEXT_SUPPORTED
3343 {
3344 static char key[] = "end marker";
3345 static char comment[] = "end";
3346 png_text text;
3347
3348 /* Use a compressed text string to test the correct interaction of text
3349 * compression and IDAT compression.
3350 */
3351 text.compression = PNG_TEXT_COMPRESSION_zTXt;
3352 text.key = key;
3353 text.text = comment;
3354 text.text_length = (sizeof comment)-1;
3355 text.itxt_length = 0;
3356 text.lang = 0;
3357 text.lang_key = 0;
3358
3359 png_set_text(pp, pi, &text, 1);
3360 }
3361#endif
3362
3363 png_write_end(pp, pi);
3364
3365 /* And store this under the appropriate id, then clean up. */
3366 store_storefile(ps, FILEID(colour_type, bit_depth, palette_number,
3367 interlace_type, 0, 0, 0));
3368
3369 store_write_reset(ps);
3370 }
3371
3372 Catch(fault)
3373 {
3374 /* Use the png_store returned by the exception. This may help the compiler
3375 * because 'ps' is not used in this branch of the setjmp. Note that fault
3376 * and ps will always be the same value.
3377 */
3378 store_write_reset(fault);
3379 }
3380}
3381
3382static void
3383make_transform_images(png_store *ps)
3384{
3385 png_byte colour_type = 0;
3386 png_byte bit_depth = 0;
3387 int palette_number = 0;
3388
3389 /* This is in case of errors. */
3390 safecat(ps->test, sizeof ps->test, 0, "make standard images");
3391
3392 /* Use next_format to enumerate all the combinations we test, including
3393 * generating multiple low bit depth palette images.
3394 */
3395 while (next_format(&colour_type, &bit_depth, &palette_number))
3396 {
3397 int interlace_type;
3398
3399 for (interlace_type = PNG_INTERLACE_NONE;
3400 interlace_type < PNG_INTERLACE_LAST; ++interlace_type)
3401 {
3402 char name[FILE_NAME_SIZE];
3403
3404 standard_name(name, sizeof name, 0, colour_type, bit_depth,
3405 palette_number, interlace_type, 0, 0, 0);
3406 make_transform_image(ps, colour_type, bit_depth, palette_number,
3407 interlace_type, name);
3408 }
3409 }
3410}
3411
3412/* The following two routines use the PNG interlace support macros from
3413 * png.h to interlace or deinterlace rows.
3414 */
3415static void
3416interlace_row(png_bytep buffer, png_const_bytep imageRow,
3417 unsigned int pixel_size, png_uint_32 w, int pass)
3418{
3419 png_uint_32 xin, xout, xstep;
3420
3421 /* Note that this can, trivially, be optimized to a memcpy on pass 7, the
3422 * code is presented this way to make it easier to understand. In practice
3423 * consult the code in the libpng source to see other ways of doing this.
3424 */
3425 xin = PNG_PASS_START_COL(pass);
3426 xstep = 1U<<PNG_PASS_COL_SHIFT(pass);
3427
3428 for (xout=0; xin<w; xin+=xstep)
3429 {
3430 pixel_copy(buffer, xout, imageRow, xin, pixel_size);
3431 ++xout;
3432 }
3433}
3434
3435static void
3436deinterlace_row(png_bytep buffer, png_const_bytep row,
3437 unsigned int pixel_size, png_uint_32 w, int pass)
3438{
3439 /* The inverse of the above, 'row' is part of row 'y' of the output image,
3440 * in 'buffer'. The image is 'w' wide and this is pass 'pass', distribute
3441 * the pixels of row into buffer and return the number written (to allow
3442 * this to be checked).
3443 */
3444 png_uint_32 xin, xout, xstep;
3445
3446 xout = PNG_PASS_START_COL(pass);
3447 xstep = 1U<<PNG_PASS_COL_SHIFT(pass);
3448
3449 for (xin=0; xout<w; xout+=xstep)
3450 {
3451 pixel_copy(buffer, xout, row, xin, pixel_size);
3452 ++xin;
3453 }
3454}
3455
3456/* Build a single row for the 'size' test images; this fills in only the
3457 * first bit_width bits of the sample row.
3458 */
3459static void
3460size_row(png_byte buffer[SIZE_ROWMAX], png_uint_32 bit_width, png_uint_32 y)
3461{
3462 /* height is in the range 1 to 16, so: */
3463 y = ((y & 1) << 7) + ((y & 2) << 6) + ((y & 4) << 5) + ((y & 8) << 4);
3464 /* the following ensures bits are set in small images: */
3465 y ^= 0xA5;
3466
3467 while (bit_width >= 8)
3468 *buffer++ = (png_byte)y++, bit_width -= 8;
3469
3470 /* There may be up to 7 remaining bits, these go in the most significant
3471 * bits of the byte.
3472 */
3473 if (bit_width > 0)
3474 {
3475 png_uint_32 mask = (1U<<(8-bit_width))-1;
3476 *buffer = (png_byte)((*buffer & mask) | (y & ~mask));
3477 }
3478}
3479
3480static void
3481make_size_image(png_store* PNG_CONST ps, png_byte PNG_CONST colour_type,
3482 png_byte PNG_CONST bit_depth, int PNG_CONST interlace_type,
3483 png_uint_32 PNG_CONST w, png_uint_32 PNG_CONST h,
3484 int PNG_CONST do_interlace)
3485{
3486 context(ps, fault);
3487
3488 Try
3489 {
3490 png_infop pi;
3491 png_structp pp;
3492 unsigned int pixel_size;
3493
3494 /* Make a name and get an appropriate id for the store: */
3495 char name[FILE_NAME_SIZE];
3496 PNG_CONST png_uint_32 id = FILEID(colour_type, bit_depth, 0/*palette*/,
3497 interlace_type, w, h, do_interlace);
3498
3499 standard_name_from_id(name, sizeof name, 0, id);
3500 pp = set_store_for_write(ps, &pi, name);
3501
3502 /* In the event of a problem return control to the Catch statement below
3503 * to do the clean up - it is not possible to 'return' directly from a Try
3504 * block.
3505 */
3506 if (pp == NULL)
3507 Throw ps;
3508
3509 png_set_IHDR(pp, pi, w, h, bit_depth, colour_type, interlace_type,
3510 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
3511
3512 if (colour_type == 3) /* palette */
3513 init_standard_palette(ps, pp, pi, 1U << bit_depth, 0/*do tRNS*/);
3514
3515 png_write_info(pp, pi);
3516
3517 /* Calculate the bit size, divide by 8 to get the byte size - this won't
3518 * overflow because we know the w values are all small enough even for
3519 * a system where 'unsigned int' is only 16 bits.
3520 */
3521 pixel_size = bit_size(pp, colour_type, bit_depth);
3522 if (png_get_rowbytes(pp, pi) != ((w * pixel_size) + 7) / 8)
3523 png_error(pp, "row size incorrect");
3524
3525 else
3526 {
3527 int npasses = npasses_from_interlace_type(pp, interlace_type);
3528 png_uint_32 y;
3529 int pass;
3530 png_byte image[16][SIZE_ROWMAX];
3531
3532 /* To help consistent error detection make the parts of this buffer
3533 * that aren't set below all '1':
3534 */
3535 memset(image, 0xff, sizeof image);
3536
3537 if (!do_interlace && npasses != png_set_interlace_handling(pp))
3538 png_error(pp, "write: png_set_interlace_handling failed");
3539
3540 /* Prepare the whole image first to avoid making it 7 times: */
3541 for (y=0; y<h; ++y)
3542 size_row(image[y], w * pixel_size, y);
3543
3544 for (pass=0; pass<npasses; ++pass)
3545 {
3546 /* The following two are for checking the macros: */
3547 PNG_CONST png_uint_32 wPass = PNG_PASS_COLS(w, pass);
3548
3549 /* If do_interlace is set we don't call png_write_row for every
3550 * row because some of them are empty. In fact, for a 1x1 image,
3551 * most of them are empty!
3552 */
3553 for (y=0; y<h; ++y)
3554 {
3555 png_const_bytep row = image[y];
3556 png_byte tempRow[SIZE_ROWMAX];
3557
3558 /* If do_interlace *and* the image is interlaced we
3559 * need a reduced interlace row; this may be reduced
3560 * to empty.
3561 */
3562 if (do_interlace && interlace_type == PNG_INTERLACE_ADAM7)
3563 {
3564 /* The row must not be written if it doesn't exist, notice
3565 * that there are two conditions here, either the row isn't
3566 * ever in the pass or the row would be but isn't wide
3567 * enough to contribute any pixels. In fact the wPass test
3568 * can be used to skip the whole y loop in this case.
3569 */
3570 if (PNG_ROW_IN_INTERLACE_PASS(y, pass) && wPass > 0)
3571 {
3572 /* Set to all 1's for error detection (libpng tends to
3573 * set unset things to 0).
3574 */
3575 memset(tempRow, 0xff, sizeof tempRow);
3576 interlace_row(tempRow, row, pixel_size, w, pass);
3577 row = tempRow;
3578 }
3579 else
3580 continue;
3581 }
3582
3583 /* Only get to here if the row has some pixels in it. */
3584 png_write_row(pp, row);
3585 }
3586 }
3587 }
3588
3589 png_write_end(pp, pi);
3590
3591 /* And store this under the appropriate id, then clean up. */
3592 store_storefile(ps, id);
3593
3594 store_write_reset(ps);
3595 }
3596
3597 Catch(fault)
3598 {
3599 /* Use the png_store returned by the exception. This may help the compiler
3600 * because 'ps' is not used in this branch of the setjmp. Note that fault
3601 * and ps will always be the same value.
3602 */
3603 store_write_reset(fault);
3604 }
3605}
3606
3607static void
3608make_size(png_store* PNG_CONST ps, png_byte PNG_CONST colour_type, int bdlo,
3609 int PNG_CONST bdhi)
3610{
3611 for (; bdlo <= bdhi; ++bdlo)
3612 {
3613 png_uint_32 width;
3614
3615 for (width = 1; width <= 16; ++width)
3616 {
3617 png_uint_32 height;
3618
3619 for (height = 1; height <= 16; ++height)
3620 {
3621 /* The four combinations of DIY interlace and interlace or not -
3622 * no interlace + DIY should be identical to no interlace with
3623 * libpng doing it.
3624 */
3625 make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_NONE,
3626 width, height, 0);
3627 make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_NONE,
3628 width, height, 1);
3629 make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_ADAM7,
3630 width, height, 0);
3631 make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_ADAM7,
3632 width, height, 1);
3633 }
3634 }
3635 }
3636}
3637
3638static void
3639make_size_images(png_store *ps)
3640{
3641 /* This is in case of errors. */
3642 safecat(ps->test, sizeof ps->test, 0, "make size images");
3643
3644 /* Arguments are colour_type, low bit depth, high bit depth
3645 */
3646 make_size(ps, 0, 0, WRITE_BDHI);
3647 make_size(ps, 2, 3, WRITE_BDHI);
3648 make_size(ps, 3, 0, 3 /*palette: max 8 bits*/);
3649 make_size(ps, 4, 3, WRITE_BDHI);
3650 make_size(ps, 6, 3, WRITE_BDHI);
3651}
3652
3653/* Return a row based on image id and 'y' for checking: */
3654static void
3655standard_row(png_structp pp, png_byte std[STANDARD_ROWMAX], png_uint_32 id,
3656 png_uint_32 y)
3657{
3658 if (WIDTH_FROM_ID(id) == 0)
3659 transform_row(pp, std, COL_FROM_ID(id), DEPTH_FROM_ID(id), y);
3660 else
3661 size_row(std, WIDTH_FROM_ID(id) * bit_size(pp, COL_FROM_ID(id),
3662 DEPTH_FROM_ID(id)), y);
3663}
3664
3665/* Tests - individual test cases */
3666/* Like 'make_standard' but errors are deliberately introduced into the calls
3667 * to ensure that they get detected - it should not be possible to write an
3668 * invalid image with libpng!
3669 */
3670#ifdef PNG_WARNINGS_SUPPORTED
3671static void
3672sBIT0_error_fn(png_structp pp, png_infop pi)
3673{
3674 /* 0 is invalid... */
3675 png_color_8 bad;
3676 bad.red = bad.green = bad.blue = bad.gray = bad.alpha = 0;
3677 png_set_sBIT(pp, pi, &bad);
3678}
3679
3680static void
3681sBIT_error_fn(png_structp pp, png_infop pi)
3682{
3683 png_byte bit_depth;
3684 png_color_8 bad;
3685
3686 if (png_get_color_type(pp, pi) == PNG_COLOR_TYPE_PALETTE)
3687 bit_depth = 8;
3688
3689 else
3690 bit_depth = png_get_bit_depth(pp, pi);
3691
3692 /* Now we know the bit depth we can easily generate an invalid sBIT entry */
3693 bad.red = bad.green = bad.blue = bad.gray = bad.alpha =
3694 (png_byte)(bit_depth+1);
3695 png_set_sBIT(pp, pi, &bad);
3696}
3697
3698static PNG_CONST struct
3699{
3700 void (*fn)(png_structp, png_infop);
3701 PNG_CONST char *msg;
3702 unsigned int warning :1; /* the error is a warning... */
3703} error_test[] =
3704 {
3705 /* no warnings makes these errors undetectable. */
3706 { sBIT0_error_fn, "sBIT(0): failed to detect error", 1 },
3707 { sBIT_error_fn, "sBIT(too big): failed to detect error", 1 },
3708 };
3709
3710static void
3711make_error(png_store* volatile psIn, png_byte PNG_CONST colour_type,
3712 png_byte bit_depth, int interlace_type, int test, png_const_charp name)
3713{
3714 png_store * volatile ps = psIn;
3715
3716 context(ps, fault);
3717
3718 Try
3719 {
3720 png_structp pp;
3721 png_infop pi;
3722
3723 pp = set_store_for_write(ps, &pi, name);
3724
3725 if (pp == NULL)
3726 Throw ps;
3727
3728 png_set_IHDR(pp, pi, transform_width(pp, colour_type, bit_depth),
3729 transform_height(pp, colour_type, bit_depth), bit_depth, colour_type,
3730 interlace_type, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
3731
3732 if (colour_type == 3) /* palette */
3733 init_standard_palette(ps, pp, pi, 1U << bit_depth, 0/*do tRNS*/);
3734
3735 /* Time for a few errors; these are in various optional chunks, the
3736 * standard tests test the standard chunks pretty well.
3737 */
3738# define exception__prev exception_prev_1
3739# define exception__env exception_env_1
3740 Try
3741 {
3742 /* Expect this to throw: */
3743 ps->expect_error = !error_test[test].warning;
3744 ps->expect_warning = error_test[test].warning;
3745 ps->saw_warning = 0;
3746 error_test[test].fn(pp, pi);
3747
3748 /* Normally the error is only detected here: */
3749 png_write_info(pp, pi);
3750
3751 /* And handle the case where it was only a warning: */
3752 if (ps->expect_warning && ps->saw_warning)
3753 Throw ps;
3754
3755 /* If we get here there is a problem, we have success - no error or
3756 * no warning - when we shouldn't have success. Log an error.
3757 */
3758 store_log(ps, pp, error_test[test].msg, 1 /*error*/);
3759 }
3760
3761 Catch (fault)
3762 ps = fault; /* expected exit, make sure ps is not clobbered */
3763#undef exception__prev
3764#undef exception__env
3765
3766 /* And clear these flags */
3767 ps->expect_error = 0;
3768 ps->expect_warning = 0;
3769
3770 /* Now write the whole image, just to make sure that the detected, or
3771 * undetected, errro has not created problems inside libpng.
3772 */
3773 if (png_get_rowbytes(pp, pi) !=
3774 transform_rowsize(pp, colour_type, bit_depth))
3775 png_error(pp, "row size incorrect");
3776
3777 else
3778 {
3779 png_uint_32 h = transform_height(pp, colour_type, bit_depth);
3780 int npasses = png_set_interlace_handling(pp);
3781 int pass;
3782
3783 if (npasses != npasses_from_interlace_type(pp, interlace_type))
3784 png_error(pp, "write: png_set_interlace_handling failed");
3785
3786 for (pass=0; pass<npasses; ++pass)
3787 {
3788 png_uint_32 y;
3789
3790 for (y=0; y<h; ++y)
3791 {
3792 png_byte buffer[TRANSFORM_ROWMAX];
3793
3794 transform_row(pp, buffer, colour_type, bit_depth, y);
3795 png_write_row(pp, buffer);
3796 }
3797 }
3798 }
3799
3800 png_write_end(pp, pi);
3801
3802 /* The following deletes the file that was just written. */
3803 store_write_reset(ps);
3804 }
3805
3806 Catch(fault)
3807 {
3808 store_write_reset(fault);
3809 }
3810}
3811
3812static int
3813make_errors(png_modifier* PNG_CONST pm, png_byte PNG_CONST colour_type,
3814 int bdlo, int PNG_CONST bdhi)
3815{
3816 for (; bdlo <= bdhi; ++bdlo)
3817 {
3818 int interlace_type;
3819
3820 for (interlace_type = PNG_INTERLACE_NONE;
3821 interlace_type < PNG_INTERLACE_LAST; ++interlace_type)
3822 {
3823 unsigned int test;
3824 char name[FILE_NAME_SIZE];
3825
3826 standard_name(name, sizeof name, 0, colour_type, 1<<bdlo, 0,
3827 interlace_type, 0, 0, 0);
3828
3829 for (test=0; test<(sizeof error_test)/(sizeof error_test[0]); ++test)
3830 {
3831 make_error(&pm->this, colour_type, DEPTH(bdlo), interlace_type,
3832 test, name);
3833
3834 if (fail(pm))
3835 return 0;
3836 }
3837 }
3838 }
3839
3840 return 1; /* keep going */
3841}
3842#endif
3843
3844static void
3845perform_error_test(png_modifier *pm)
3846{
3847#ifdef PNG_WARNINGS_SUPPORTED /* else there are no cases that work! */
3848 /* Need to do this here because we just write in this test. */
3849 safecat(pm->this.test, sizeof pm->this.test, 0, "error test");
3850
3851 if (!make_errors(pm, 0, 0, WRITE_BDHI))
3852 return;
3853
3854 if (!make_errors(pm, 2, 3, WRITE_BDHI))
3855 return;
3856
3857 if (!make_errors(pm, 3, 0, 3))
3858 return;
3859
3860 if (!make_errors(pm, 4, 3, WRITE_BDHI))
3861 return;
3862
3863 if (!make_errors(pm, 6, 3, WRITE_BDHI))
3864 return;
3865#else
3866 UNUSED(pm)
3867#endif
3868}
3869
3870/* This is just to validate the internal PNG formatting code - if this fails
3871 * then the warning messages the library outputs will probably be garbage.
3872 */
3873static void
3874perform_formatting_test(png_store *volatile ps)
3875{
3876#ifdef PNG_TIME_RFC1123_SUPPORTED
3877 /* The handle into the formatting code is the RFC1123 support; this test does
3878 * nothing if that is compiled out.
3879 */
3880 context(ps, fault);
3881
3882 Try
3883 {
3884 png_const_charp correct = "29 Aug 2079 13:53:60 +0000";
3885 png_const_charp result;
3886 png_structp pp;
3887 png_time pt;
3888
3889 pp = set_store_for_write(ps, NULL, "libpng formatting test");
3890
3891 if (pp == NULL)
3892 Throw ps;
3893
3894
3895 /* Arbitrary settings: */
3896 pt.year = 2079;
3897 pt.month = 8;
3898 pt.day = 29;
3899 pt.hour = 13;
3900 pt.minute = 53;
3901 pt.second = 60; /* a leap second */
3902
3903 result = png_convert_to_rfc1123(pp, &pt);
3904
3905 if (result == NULL)
3906 png_error(pp, "png_convert_to_rfc1123 failed");
3907
3908 if (strcmp(result, correct) != 0)
3909 {
3910 size_t pos = 0;
3911 char msg[128];
3912
3913 pos = safecat(msg, sizeof msg, pos, "png_convert_to_rfc1123(");
3914 pos = safecat(msg, sizeof msg, pos, correct);
3915 pos = safecat(msg, sizeof msg, pos, ") returned: '");
3916 pos = safecat(msg, sizeof msg, pos, result);
3917 pos = safecat(msg, sizeof msg, pos, "'");
3918
3919 png_error(pp, msg);
3920 }
3921
3922 store_write_reset(ps);
3923 }
3924
3925 Catch(fault)
3926 {
3927 store_write_reset(fault);
3928 }
3929#else
3930 UNUSED(ps)
3931#endif
3932}
3933
3934/* Because we want to use the same code in both the progressive reader and the
3935 * sequential reader it is necessary to deal with the fact that the progressive
3936 * reader callbacks only have one parameter (png_get_progressive_ptr()), so this
3937 * must contain all the test parameters and all the local variables directly
3938 * accessible to the sequential reader implementation.
3939 *
3940 * The technique adopted is to reinvent part of what Dijkstra termed a
3941 * 'display'; an array of pointers to the stack frames of enclosing functions so
3942 * that a nested function definition can access the local (C auto) variables of
3943 * the functions that contain its definition. In fact C provides the first
3944 * pointer (the local variables - the stack frame pointer) and the last (the
3945 * global variables - the BCPL global vector typically implemented as global
3946 * addresses), this code requires one more pointer to make the display - the
3947 * local variables (and function call parameters) of the function that actually
3948 * invokes either the progressive or sequential reader.
3949 *
3950 * Perhaps confusingly this technique is confounded with classes - the
3951 * 'standard_display' defined here is sub-classed as the 'gamma_display' below.
3952 * A gamma_display is a standard_display, taking advantage of the ANSI-C
3953 * requirement that the pointer to the first member of a structure must be the
3954 * same as the pointer to the structure. This allows us to reuse standard_
3955 * functions in the gamma test code; something that could not be done with
3956 * nested functions!
3957 */
3958typedef struct standard_display
3959{
3960 png_store* ps; /* Test parameters (passed to the function) */
3961 png_byte colour_type;
3962 png_byte bit_depth;
3963 png_byte red_sBIT; /* Input data sBIT values. */
3964 png_byte green_sBIT;
3965 png_byte blue_sBIT;
3966 png_byte alpha_sBIT;
3967 int interlace_type;
3968 png_uint_32 id; /* Calculated file ID */
3969 png_uint_32 w; /* Width of image */
3970 png_uint_32 h; /* Height of image */
3971 int npasses; /* Number of interlaced passes */
3972 png_uint_32 pixel_size; /* Width of one pixel in bits */
3973 png_uint_32 bit_width; /* Width of output row in bits */
3974 size_t cbRow; /* Bytes in a row of the output image */
3975 int do_interlace; /* Do interlacing internally */
3976 int is_transparent; /* Transparency information was present. */
3977 int speed; /* Doing a speed test */
3978 int use_update_info;/* Call update_info, not start_image */
3979 struct
3980 {
3981 png_uint_16 red;
3982 png_uint_16 green;
3983 png_uint_16 blue;
3984 } transparent; /* The transparent color, if set. */
3985 int npalette; /* Number of entries in the palette. */
3986 store_palette
3987 palette;
3988} standard_display;
3989
3990static void
3991standard_display_init(standard_display *dp, png_store* ps, png_uint_32 id,
3992 int do_interlace, int use_update_info)
3993{
3994 memset(dp, 0, sizeof *dp);
3995
3996 dp->ps = ps;
3997 dp->colour_type = COL_FROM_ID(id);
3998 dp->bit_depth = DEPTH_FROM_ID(id);
3999 if (dp->bit_depth < 1 || dp->bit_depth > 16)
4000 internal_error(ps, "internal: bad bit depth");
4001 if (dp->colour_type == 3)
4002 dp->red_sBIT = dp->blue_sBIT = dp->green_sBIT = dp->alpha_sBIT = 8;
4003 else
4004 dp->red_sBIT = dp->blue_sBIT = dp->green_sBIT = dp->alpha_sBIT =
4005 dp->bit_depth;
4006 dp->interlace_type = INTERLACE_FROM_ID(id);
4007 dp->id = id;
4008 /* All the rest are filled in after the read_info: */
4009 dp->w = 0;
4010 dp->h = 0;
4011 dp->npasses = 0;
4012 dp->pixel_size = 0;
4013 dp->bit_width = 0;
4014 dp->cbRow = 0;
4015 dp->do_interlace = do_interlace;
4016 dp->is_transparent = 0;
4017 dp->speed = ps->speed;
4018 dp->use_update_info = use_update_info;
4019 dp->npalette = 0;
4020 /* Preset the transparent color to black: */
4021 memset(&dp->transparent, 0, sizeof dp->transparent);
4022 /* Preset the palette to full intensity/opaque througout: */
4023 memset(dp->palette, 0xff, sizeof dp->palette);
4024}
4025
4026/* Initialize the palette fields - this must be done later because the palette
4027 * comes from the particular png_store_file that is selected.
4028 */
4029static void
4030standard_palette_init(standard_display *dp)
4031{
4032 store_palette_entry *palette = store_current_palette(dp->ps, &dp->npalette);
4033
4034 /* The remaining entries remain white/opaque. */
4035 if (dp->npalette > 0)
4036 {
4037 int i = dp->npalette;
4038 memcpy(dp->palette, palette, i * sizeof *palette);
4039
4040 /* Check for a non-opaque palette entry: */
4041 while (--i >= 0)
4042 if (palette[i].alpha < 255)
4043 break;
4044
4045# ifdef __GNUC__
4046 /* GCC can't handle the more obviously optimizable version. */
4047 if (i >= 0)
4048 dp->is_transparent = 1;
4049 else
4050 dp->is_transparent = 0;
4051# else
4052 dp->is_transparent = (i >= 0);
4053# endif
4054 }
4055}
4056
4057/* Utility to read the palette from the PNG file and convert it into
4058 * store_palette format. This returns 1 if there is any transparency in the
4059 * palette (it does not check for a transparent colour in the non-palette case.)
4060 */
4061static int
4062read_palette(store_palette palette, int *npalette, png_structp pp, png_infop pi)
4063{
4064 png_colorp pal;
4065 png_bytep trans_alpha;
4066 int num;
4067
4068 pal = 0;
4069 *npalette = -1;
4070
4071 if (png_get_PLTE(pp, pi, &pal, npalette) & PNG_INFO_PLTE)
4072 {
4073 int i = *npalette;
4074
4075 if (i <= 0 || i > 256)
4076 png_error(pp, "validate: invalid PLTE count");
4077
4078 while (--i >= 0)
4079 {
4080 palette[i].red = pal[i].red;
4081 palette[i].green = pal[i].green;
4082 palette[i].blue = pal[i].blue;
4083 }
4084
4085 /* Mark the remainder of the entries with a flag value (other than
4086 * white/opaque which is the flag value stored above.)
4087 */
4088 memset(palette + *npalette, 126, (256-*npalette) * sizeof *palette);
4089 }
4090
4091 else /* !png_get_PLTE */
4092 {
4093 if (*npalette != (-1))
4094 png_error(pp, "validate: invalid PLTE result");
4095 /* But there is no palette, so record this: */
4096 *npalette = 0;
4097 memset(palette, 113, sizeof (store_palette));
4098 }
4099
4100 trans_alpha = 0;
4101 num = 2; /* force error below */
4102 if ((png_get_tRNS(pp, pi, &trans_alpha, &num, 0) & PNG_INFO_tRNS) != 0 &&
4103 (trans_alpha != NULL || num != 1/*returns 1 for a transparent color*/) &&
4104 /* Oops, if a palette tRNS gets expanded png_read_update_info (at least so
4105 * far as 1.5.4) does not remove the trans_alpha pointer, only num_trans,
4106 * so in the above call we get a success, we get a pointer (who knows what
4107 * to) and we get num_trans == 0:
4108 */
4109 !(trans_alpha != NULL && num == 0)) /* TODO: fix this in libpng. */
4110 {
4111 int i;
4112
4113 /* Any of these are crash-worthy - given the implementation of
4114 * png_get_tRNS up to 1.5 an app won't crash if it just checks the
4115 * result above and fails to check that the variables it passed have
4116 * actually been filled in! Note that if the app were to pass the
4117 * last, png_color_16p, variable too it couldn't rely on this.
4118 */
4119 if (trans_alpha == NULL || num <= 0 || num > 256 || num > *npalette)
4120 png_error(pp, "validate: unexpected png_get_tRNS (palette) result");
4121
4122 for (i=0; i<num; ++i)
4123 palette[i].alpha = trans_alpha[i];
4124
4125 for (num=*npalette; i<num; ++i)
4126 palette[i].alpha = 255;
4127
4128 for (; i<256; ++i)
4129 palette[i].alpha = 33; /* flag value */
4130
4131 return 1; /* transparency */
4132 }
4133
4134 else
4135 {
4136 /* No palette transparency - just set the alpha channel to opaque. */
4137 int i;
4138
4139 for (i=0, num=*npalette; i<num; ++i)
4140 palette[i].alpha = 255;
4141
4142 for (; i<256; ++i)
4143 palette[i].alpha = 55; /* flag value */
4144
4145 return 0; /* no transparency */
4146 }
4147}
4148
4149/* Utility to validate the palette if it should not have changed (the
4150 * non-transform case).
4151 */
4152static void
4153standard_palette_validate(standard_display *dp, png_structp pp, png_infop pi)
4154{
4155 int npalette;
4156 store_palette palette;
4157
4158 if (read_palette(palette, &npalette, pp, pi) != dp->is_transparent)
4159 png_error(pp, "validate: palette transparency changed");
4160
4161 if (npalette != dp->npalette)
4162 {
4163 size_t pos = 0;
4164 char msg[64];
4165
4166 pos = safecat(msg, sizeof msg, pos, "validate: palette size changed: ");
4167 pos = safecatn(msg, sizeof msg, pos, dp->npalette);
4168 pos = safecat(msg, sizeof msg, pos, " -> ");
4169 pos = safecatn(msg, sizeof msg, pos, npalette);
4170 png_error(pp, msg);
4171 }
4172
4173 {
4174 int i = npalette; /* npalette is aliased */
4175
4176 while (--i >= 0)
4177 if (palette[i].red != dp->palette[i].red ||
4178 palette[i].green != dp->palette[i].green ||
4179 palette[i].blue != dp->palette[i].blue ||
4180 palette[i].alpha != dp->palette[i].alpha)
4181 png_error(pp, "validate: PLTE or tRNS chunk changed");
4182 }
4183}
4184
4185/* By passing a 'standard_display' the progressive callbacks can be used
4186 * directly by the sequential code, the functions suffixed "_imp" are the
4187 * implementations, the functions without the suffix are the callbacks.
4188 *
4189 * The code for the info callback is split into two because this callback calls
4190 * png_read_update_info or png_start_read_image and what gets called depends on
4191 * whether the info needs updating (we want to test both calls in pngvalid.)
4192 */
4193static void
4194standard_info_part1(standard_display *dp, png_structp pp, png_infop pi)
4195{
4196 if (png_get_bit_depth(pp, pi) != dp->bit_depth)
4197 png_error(pp, "validate: bit depth changed");
4198
4199 if (png_get_color_type(pp, pi) != dp->colour_type)
4200 png_error(pp, "validate: color type changed");
4201
4202 if (png_get_filter_type(pp, pi) != PNG_FILTER_TYPE_BASE)
4203 png_error(pp, "validate: filter type changed");
4204
4205 if (png_get_interlace_type(pp, pi) != dp->interlace_type)
4206 png_error(pp, "validate: interlacing changed");
4207
4208 if (png_get_compression_type(pp, pi) != PNG_COMPRESSION_TYPE_BASE)
4209 png_error(pp, "validate: compression type changed");
4210
4211 dp->w = png_get_image_width(pp, pi);
4212
4213 if (dp->w != standard_width(pp, dp->id))
4214 png_error(pp, "validate: image width changed");
4215
4216 dp->h = png_get_image_height(pp, pi);
4217
4218 if (dp->h != standard_height(pp, dp->id))
4219 png_error(pp, "validate: image height changed");
4220
4221 /* Record (but don't check at present) the input sBIT according to the colour
4222 * type information.
4223 */
4224 {
4225 png_color_8p sBIT = 0;
4226
4227 if (png_get_sBIT(pp, pi, &sBIT) & PNG_INFO_sBIT)
4228 {
4229 int sBIT_invalid = 0;
4230
4231 if (sBIT == 0)
4232 png_error(pp, "validate: unexpected png_get_sBIT result");
4233
4234 if (dp->colour_type & PNG_COLOR_MASK_COLOR)
4235 {
4236 if (sBIT->red == 0 || sBIT->red > dp->bit_depth)
4237 sBIT_invalid = 1;
4238 else
4239 dp->red_sBIT = sBIT->red;
4240
4241 if (sBIT->green == 0 || sBIT->green > dp->bit_depth)
4242 sBIT_invalid = 1;
4243 else
4244 dp->green_sBIT = sBIT->green;
4245
4246 if (sBIT->blue == 0 || sBIT->blue > dp->bit_depth)
4247 sBIT_invalid = 1;
4248 else
4249 dp->blue_sBIT = sBIT->blue;
4250 }
4251
4252 else /* !COLOR */
4253 {
4254 if (sBIT->gray == 0 || sBIT->gray > dp->bit_depth)
4255 sBIT_invalid = 1;
4256 else
4257 dp->blue_sBIT = dp->green_sBIT = dp->red_sBIT = sBIT->gray;
4258 }
4259
4260 /* All 8 bits in tRNS for a palette image are significant - see the
4261 * spec.
4262 */
4263 if (dp->colour_type & PNG_COLOR_MASK_ALPHA)
4264 {
4265 if (sBIT->alpha == 0 || sBIT->alpha > dp->bit_depth)
4266 sBIT_invalid = 1;
4267 else
4268 dp->alpha_sBIT = sBIT->alpha;
4269 }
4270
4271 if (sBIT_invalid)
4272 png_error(pp, "validate: sBIT value out of range");
4273 }
4274 }
4275
4276 /* Important: this is validating the value *before* any transforms have been
4277 * put in place. It doesn't matter for the standard tests, where there are
4278 * no transforms, but it does for other tests where rowbytes may change after
4279 * png_read_update_info.
4280 */
4281 if (png_get_rowbytes(pp, pi) != standard_rowsize(pp, dp->id))
4282 png_error(pp, "validate: row size changed");
4283
4284 /* Validate the colour type 3 palette (this can be present on other color
4285 * types.)
4286 */
4287 standard_palette_validate(dp, pp, pi);
4288
4289 /* In any case always check for a tranparent color (notice that the
4290 * colour type 3 case must not give a successful return on the get_tRNS call
4291 * with these arguments!)
4292 */
4293 {
4294 png_color_16p trans_color = 0;
4295
4296 if (png_get_tRNS(pp, pi, 0, 0, &trans_color) & PNG_INFO_tRNS)
4297 {
4298 if (trans_color == 0)
4299 png_error(pp, "validate: unexpected png_get_tRNS (color) result");
4300
4301 switch (dp->colour_type)
4302 {
4303 case 0:
4304 dp->transparent.red = dp->transparent.green = dp->transparent.blue =
4305 trans_color->gray;
4306 dp->is_transparent = 1;
4307 break;
4308
4309 case 2:
4310 dp->transparent.red = trans_color->red;
4311 dp->transparent.green = trans_color->green;
4312 dp->transparent.blue = trans_color->blue;
4313 dp->is_transparent = 1;
4314 break;
4315
4316 case 3:
4317 /* Not expected because it should result in the array case
4318 * above.
4319 */
4320 png_error(pp, "validate: unexpected png_get_tRNS result");
4321 break;
4322
4323 default:
4324 png_error(pp, "validate: invalid tRNS chunk with alpha image");
4325 }
4326 }
4327 }
4328
4329 /* Read the number of passes - expected to match the value used when
4330 * creating the image (interlaced or not). This has the side effect of
4331 * turning on interlace handling (if do_interlace is not set.)
4332 */
4333 dp->npasses = npasses_from_interlace_type(pp, dp->interlace_type);
4334 if (!dp->do_interlace && dp->npasses != png_set_interlace_handling(pp))
4335 png_error(pp, "validate: file changed interlace type");
4336
4337 /* Caller calls png_read_update_info or png_start_read_image now, then calls
4338 * part2.
4339 */
4340}
4341
4342/* This must be called *after* the png_read_update_info call to get the correct
4343 * 'rowbytes' value, otherwise png_get_rowbytes will refer to the untransformed
4344 * image.
4345 */
4346static void
4347standard_info_part2(standard_display *dp, png_structp pp, png_infop pi,
4348 int nImages)
4349{
4350 /* Record cbRow now that it can be found. */
4351 dp->pixel_size = bit_size(pp, png_get_color_type(pp, pi),
4352 png_get_bit_depth(pp, pi));
4353 dp->bit_width = png_get_image_width(pp, pi) * dp->pixel_size;
4354 dp->cbRow = png_get_rowbytes(pp, pi);
4355
4356 /* Validate the rowbytes here again. */
4357 if (dp->cbRow != (dp->bit_width+7)/8)
4358 png_error(pp, "bad png_get_rowbytes calculation");
4359
4360 /* Then ensure there is enough space for the output image(s). */
4361 store_ensure_image(dp->ps, pp, nImages, dp->cbRow, dp->h);
4362}
4363
4364static void
4365standard_info_imp(standard_display *dp, png_structp pp, png_infop pi,
4366 int nImages)
4367{
4368 /* Note that the validation routine has the side effect of turning on
4369 * interlace handling in the subsequent code.
4370 */
4371 standard_info_part1(dp, pp, pi);
4372
4373 /* And the info callback has to call this (or png_read_update_info - see
4374 * below in the png_modifier code for that variant.
4375 */
4376 if (dp->use_update_info)
4377 {
4378 /* For debugging the effect of multiple calls: */
4379 int i = dp->use_update_info;
4380 while (i-- > 0)
4381 png_read_update_info(pp, pi);
4382 }
4383
4384 else
4385 png_start_read_image(pp);
4386
4387 /* Validate the height, width and rowbytes plus ensure that sufficient buffer
4388 * exists for decoding the image.
4389 */
4390 standard_info_part2(dp, pp, pi, nImages);
4391}
4392
4393static void
4394standard_info(png_structp pp, png_infop pi)
4395{
4396 standard_display *dp = voidcast(standard_display*,
4397 png_get_progressive_ptr(pp));
4398
4399 /* Call with nImages==1 because the progressive reader can only produce one
4400 * image.
4401 */
4402 standard_info_imp(dp, pp, pi, 1 /*only one image*/);
4403}
4404
4405static void
4406progressive_row(png_structp pp, png_bytep new_row, png_uint_32 y, int pass)
4407{
4408 PNG_CONST standard_display *dp = voidcast(standard_display*,
4409 png_get_progressive_ptr(pp));
4410
4411 /* When handling interlacing some rows will be absent in each pass, the
4412 * callback still gets called, but with a NULL pointer. This is checked
4413 * in the 'else' clause below. We need our own 'cbRow', but we can't call
4414 * png_get_rowbytes because we got no info structure.
4415 */
4416 if (new_row != NULL)
4417 {
4418 png_bytep row;
4419
4420 /* In the case where the reader doesn't do the interlace it gives
4421 * us the y in the sub-image:
4422 */
4423 if (dp->do_interlace && dp->interlace_type == PNG_INTERLACE_ADAM7)
4424 {
4425#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
4426 /* Use this opportunity to validate the png 'current' APIs: */
4427 if (y != png_get_current_row_number(pp))
4428 png_error(pp, "png_get_current_row_number is broken");
4429
4430 if (pass != png_get_current_pass_number(pp))
4431 png_error(pp, "png_get_current_pass_number is broken");
4432#endif
4433
4434 y = PNG_ROW_FROM_PASS_ROW(y, pass);
4435 }
4436
4437 /* Validate this just in case. */
4438 if (y >= dp->h)
4439 png_error(pp, "invalid y to progressive row callback");
4440
4441 row = store_image_row(dp->ps, pp, 0, y);
4442
4443#ifdef PNG_READ_INTERLACING_SUPPORTED
4444 /* Combine the new row into the old: */
4445 if (dp->do_interlace)
4446 {
4447 if (dp->interlace_type == PNG_INTERLACE_ADAM7)
4448 deinterlace_row(row, new_row, dp->pixel_size, dp->w, pass);
4449 else
4450 row_copy(row, new_row, dp->pixel_size * dp->w);
4451 }
4452 else
4453 png_progressive_combine_row(pp, row, new_row);
4454 } else if (dp->interlace_type == PNG_INTERLACE_ADAM7 &&
4455 PNG_ROW_IN_INTERLACE_PASS(y, pass) &&
4456 PNG_PASS_COLS(dp->w, pass) > 0)
4457 png_error(pp, "missing row in progressive de-interlacing");
4458#endif /* PNG_READ_INTERLACING_SUPPORTED */
4459}
4460
4461static void
4462sequential_row(standard_display *dp, png_structp pp, png_infop pi,
4463 PNG_CONST int iImage, PNG_CONST int iDisplay)
4464{
4465 PNG_CONST int npasses = dp->npasses;
4466 PNG_CONST int do_interlace = dp->do_interlace &&
4467 dp->interlace_type == PNG_INTERLACE_ADAM7;
4468 PNG_CONST png_uint_32 height = standard_height(pp, dp->id);
4469 PNG_CONST png_uint_32 width = standard_width(pp, dp->id);
4470 PNG_CONST png_store* ps = dp->ps;
4471 int pass;
4472
4473 for (pass=0; pass<npasses; ++pass)
4474 {
4475 png_uint_32 y;
4476 png_uint_32 wPass = PNG_PASS_COLS(width, pass);
4477
4478 for (y=0; y<height; ++y)
4479 {
4480 if (do_interlace)
4481 {
4482 /* wPass may be zero or this row may not be in this pass.
4483 * png_read_row must not be called in either case.
4484 */
4485 if (wPass > 0 && PNG_ROW_IN_INTERLACE_PASS(y, pass))
4486 {
4487 /* Read the row into a pair of temporary buffers, then do the
4488 * merge here into the output rows.
4489 */
4490 png_byte row[STANDARD_ROWMAX], display[STANDARD_ROWMAX];
4491
4492 /* The following aids (to some extent) error detection - we can
4493 * see where png_read_row wrote. Use opposite values in row and
4494 * display to make this easier. Don't use 0xff (which is used in
4495 * the image write code to fill unused bits) or 0 (which is a
4496 * likely value to overwrite unused bits with).
4497 */
4498 memset(row, 0xc5, sizeof row);
4499 memset(display, 0x5c, sizeof display);
4500
4501 png_read_row(pp, row, display);
4502
4503 if (iImage >= 0)
4504 deinterlace_row(store_image_row(ps, pp, iImage, y), row,
4505 dp->pixel_size, dp->w, pass);
4506
4507 if (iDisplay >= 0)
4508 deinterlace_row(store_image_row(ps, pp, iDisplay, y), display,
4509 dp->pixel_size, dp->w, pass);
4510 }
4511 }
4512 else
4513 png_read_row(pp,
4514 iImage >= 0 ? store_image_row(ps, pp, iImage, y) : NULL,
4515 iDisplay >= 0 ? store_image_row(ps, pp, iDisplay, y) : NULL);
4516 }
4517 }
4518
4519 /* And finish the read operation (only really necessary if the caller wants
4520 * to find additional data in png_info from chunks after the last IDAT.)
4521 */
4522 png_read_end(pp, pi);
4523}
4524
4525static void
4526standard_row_validate(standard_display *dp, png_structp pp,
4527 int iImage, int iDisplay, png_uint_32 y)
4528{
4529 int where;
4530 png_byte std[STANDARD_ROWMAX];
4531
4532 /* The row must be pre-initialized to the magic number here for the size
4533 * tests to pass:
4534 */
4535 memset(std, 178, sizeof std);
4536 standard_row(pp, std, dp->id, y);
4537
4538 /* At the end both the 'row' and 'display' arrays should end up identical.
4539 * In earlier passes 'row' will be partially filled in, with only the pixels
4540 * that have been read so far, but 'display' will have those pixels
4541 * replicated to fill the unread pixels while reading an interlaced image.
4542#if PNG_LIBPNG_VER < 10506
4543 * The side effect inside the libpng sequential reader is that the 'row'
4544 * array retains the correct values for unwritten pixels within the row
4545 * bytes, while the 'display' array gets bits off the end of the image (in
4546 * the last byte) trashed. Unfortunately in the progressive reader the
4547 * row bytes are always trashed, so we always do a pixel_cmp here even though
4548 * a memcmp of all cbRow bytes will succeed for the sequential reader.
4549#endif
4550 */
4551 if (iImage >= 0 &&
4552 (where = pixel_cmp(std, store_image_row(dp->ps, pp, iImage, y),
4553 dp->bit_width)) != 0)
4554 {
4555 char msg[64];
4556 sprintf(msg, "PNG image row[%d][%d] changed from %.2x to %.2x", y,
4557 where-1, std[where-1],
4558 store_image_row(dp->ps, pp, iImage, y)[where-1]);
4559 png_error(pp, msg);
4560 }
4561
4562#if PNG_LIBPNG_VER < 10506
4563 /* In this case use pixel_cmp because we need to compare a partial
4564 * byte at the end of the row if the row is not an exact multiple
4565 * of 8 bits wide. (This is fixed in libpng-1.5.6 and pixel_cmp is
4566 * changed to match!)
4567 */
4568#endif
4569 if (iDisplay >= 0 &&
4570 (where = pixel_cmp(std, store_image_row(dp->ps, pp, iDisplay, y),
4571 dp->bit_width)) != 0)
4572 {
4573 char msg[64];
4574 sprintf(msg, "display row[%d][%d] changed from %.2x to %.2x", y,
4575 where-1, std[where-1],
4576 store_image_row(dp->ps, pp, iDisplay, y)[where-1]);
4577 png_error(pp, msg);
4578 }
4579}
4580
4581static void
4582standard_image_validate(standard_display *dp, png_structp pp, int iImage,
4583 int iDisplay)
4584{
4585 png_uint_32 y;
4586
4587 if (iImage >= 0)
4588 store_image_check(dp->ps, pp, iImage);
4589
4590 if (iDisplay >= 0)
4591 store_image_check(dp->ps, pp, iDisplay);
4592
4593 for (y=0; y<dp->h; ++y)
4594 standard_row_validate(dp, pp, iImage, iDisplay, y);
4595
4596 /* This avoids false positives if the validation code is never called! */
4597 dp->ps->validated = 1;
4598}
4599
4600static void
4601standard_end(png_structp pp, png_infop pi)
4602{
4603 standard_display *dp = voidcast(standard_display*,
4604 png_get_progressive_ptr(pp));
4605
4606 UNUSED(pi)
4607
4608 /* Validate the image - progressive reading only produces one variant for
4609 * interlaced images.
4610 */
4611 standard_image_validate(dp, pp, 0, -1);
4612}
4613
4614/* A single test run checking the standard image to ensure it is not damaged. */
4615static void
4616standard_test(png_store* PNG_CONST psIn, png_uint_32 PNG_CONST id,
4617 int do_interlace, int use_update_info)
4618{
4619 standard_display d;
4620 context(psIn, fault);
4621
4622 /* Set up the display (stack frame) variables from the arguments to the
4623 * function and initialize the locals that are filled in later.
4624 */
4625 standard_display_init(&d, psIn, id, do_interlace, use_update_info);
4626
4627 /* Everything is protected by a Try/Catch. The functions called also
4628 * typically have local Try/Catch blocks.
4629 */
4630 Try
4631 {
4632 png_structp pp;
4633 png_infop pi;
4634
4635 /* Get a png_struct for reading the image. This will throw an error if it
4636 * fails, so we don't need to check the result.
4637 */
4638 pp = set_store_for_read(d.ps, &pi, d.id,
4639 d.do_interlace ? (d.ps->progressive ?
4640 "pngvalid progressive deinterlacer" :
4641 "pngvalid sequential deinterlacer") : (d.ps->progressive ?
4642 "progressive reader" : "sequential reader"));
4643
4644 /* Initialize the palette correctly from the png_store_file. */
4645 standard_palette_init(&d);
4646
4647 /* Introduce the correct read function. */
4648 if (d.ps->progressive)
4649 {
4650 png_set_progressive_read_fn(pp, &d, standard_info, progressive_row,
4651 standard_end);
4652
4653 /* Now feed data into the reader until we reach the end: */
4654 store_progressive_read(d.ps, pp, pi);
4655 }
4656 else
4657 {
4658 /* Note that this takes the store, not the display. */
4659 png_set_read_fn(pp, d.ps, store_read);
4660
4661 /* Check the header values: */
4662 png_read_info(pp, pi);
4663
4664 /* The code tests both versions of the images that the sequential
4665 * reader can produce.
4666 */
4667 standard_info_imp(&d, pp, pi, 2 /*images*/);
4668
4669 /* Need the total bytes in the image below; we can't get to this point
4670 * unless the PNG file values have been checked against the expected
4671 * values.
4672 */
4673 {
4674 sequential_row(&d, pp, pi, 0, 1);
4675
4676 /* After the last pass loop over the rows again to check that the
4677 * image is correct.
4678 */
4679 if (!d.speed)
4680 standard_image_validate(&d, pp, 0, 1);
4681 else
4682 d.ps->validated = 1;
4683 }
4684 }
4685
4686 /* Check for validation. */
4687 if (!d.ps->validated)
4688 png_error(pp, "image read failed silently");
4689
4690 /* Successful completion. */
4691 }
4692
4693 Catch(fault)
4694 d.ps = fault; /* make sure this hasn't been clobbered. */
4695
4696 /* In either case clean up the store. */
4697 store_read_reset(d.ps);
4698}
4699
4700static int
4701test_standard(png_modifier* PNG_CONST pm, png_byte PNG_CONST colour_type,
4702 int bdlo, int PNG_CONST bdhi)
4703{
4704 for (; bdlo <= bdhi; ++bdlo)
4705 {
4706 int interlace_type;
4707
4708 for (interlace_type = PNG_INTERLACE_NONE;
4709 interlace_type < PNG_INTERLACE_LAST; ++interlace_type)
4710 {
4711 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
4712 interlace_type, 0, 0, 0), 0/*do_interlace*/, pm->use_update_info);
4713
4714 if (fail(pm))
4715 return 0;
4716 }
4717 }
4718
4719 return 1; /* keep going */
4720}
4721
4722static void
4723perform_standard_test(png_modifier *pm)
4724{
4725 /* Test each colour type over the valid range of bit depths (expressed as
4726 * log2(bit_depth) in turn, stop as soon as any error is detected.
4727 */
4728 if (!test_standard(pm, 0, 0, READ_BDHI))
4729 return;
4730
4731 if (!test_standard(pm, 2, 3, READ_BDHI))
4732 return;
4733
4734 if (!test_standard(pm, 3, 0, 3))
4735 return;
4736
4737 if (!test_standard(pm, 4, 3, READ_BDHI))
4738 return;
4739
4740 if (!test_standard(pm, 6, 3, READ_BDHI))
4741 return;
4742}
4743
4744
4745/********************************** SIZE TESTS ********************************/
4746static int
4747test_size(png_modifier* PNG_CONST pm, png_byte PNG_CONST colour_type,
4748 int bdlo, int PNG_CONST bdhi)
4749{
4750 /* Run the tests on each combination.
4751 *
4752 * NOTE: on my 32 bit x86 each of the following blocks takes
4753 * a total of 3.5 seconds if done across every combo of bit depth
4754 * width and height. This is a waste of time in practice, hence the
4755 * hinc and winc stuff:
4756 */
4757 static PNG_CONST png_byte hinc[] = {1, 3, 11, 1, 5};
4758 static PNG_CONST png_byte winc[] = {1, 9, 5, 7, 1};
4759 for (; bdlo <= bdhi; ++bdlo)
4760 {
4761 png_uint_32 h, w;
4762
4763 for (h=1; h<=16; h+=hinc[bdlo]) for (w=1; w<=16; w+=winc[bdlo])
4764 {
4765 /* First test all the 'size' images against the sequential
4766 * reader using libpng to deinterlace (where required.) This
4767 * validates the write side of libpng. There are four possibilities
4768 * to validate.
4769 */
4770 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
4771 PNG_INTERLACE_NONE, w, h, 0), 0/*do_interlace*/,
4772 pm->use_update_info);
4773
4774 if (fail(pm))
4775 return 0;
4776
4777 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
4778 PNG_INTERLACE_NONE, w, h, 1), 0/*do_interlace*/,
4779 pm->use_update_info);
4780
4781 if (fail(pm))
4782 return 0;
4783
4784 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
4785 PNG_INTERLACE_ADAM7, w, h, 0), 0/*do_interlace*/,
4786 pm->use_update_info);
4787
4788 if (fail(pm))
4789 return 0;
4790
4791 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
4792 PNG_INTERLACE_ADAM7, w, h, 1), 0/*do_interlace*/,
4793 pm->use_update_info);
4794
4795 if (fail(pm))
4796 return 0;
4797
4798 /* Now validate the interlaced read side - do_interlace true,
4799 * in the progressive case this does actually make a difference
4800 * to the code used in the non-interlaced case too.
4801 */
4802 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
4803 PNG_INTERLACE_NONE, w, h, 0), 1/*do_interlace*/,
4804 pm->use_update_info);
4805
4806 if (fail(pm))
4807 return 0;
4808
4809 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
4810 PNG_INTERLACE_ADAM7, w, h, 0), 1/*do_interlace*/,
4811 pm->use_update_info);
4812
4813 if (fail(pm))
4814 return 0;
4815 }
4816 }
4817
4818 return 1; /* keep going */
4819}
4820
4821static void
4822perform_size_test(png_modifier *pm)
4823{
4824 /* Test each colour type over the valid range of bit depths (expressed as
4825 * log2(bit_depth) in turn, stop as soon as any error is detected.
4826 */
4827 if (!test_size(pm, 0, 0, READ_BDHI))
4828 return;
4829
4830 if (!test_size(pm, 2, 3, READ_BDHI))
4831 return;
4832
4833 /* For the moment don't do the palette test - it's a waste of time when
4834 * compared to the grayscale test.
4835 */
4836#if 0
4837 if (!test_size(pm, 3, 0, 3))
4838 return;
4839#endif
4840
4841 if (!test_size(pm, 4, 3, READ_BDHI))
4842 return;
4843
4844 if (!test_size(pm, 6, 3, READ_BDHI))
4845 return;
4846}
4847
4848
4849/******************************* TRANSFORM TESTS ******************************/
4850#ifdef PNG_READ_TRANSFORMS_SUPPORTED
4851/* A set of tests to validate libpng image transforms. The possibilities here
4852 * are legion because the transforms can be combined in a combinatorial
4853 * fashion. To deal with this some measure of restraint is required, otherwise
4854 * the tests would take forever.
4855 */
4856typedef struct image_pixel
4857{
4858 /* A local (pngvalid) representation of a PNG pixel, in all its
4859 * various forms.
4860 */
4861 unsigned int red, green, blue, alpha; /* For non-palette images. */
4862 unsigned int palette_index; /* For a palette image. */
4863 png_byte colour_type; /* As in the spec. */
4864 png_byte bit_depth; /* Defines bit size in row */
4865 png_byte sample_depth; /* Scale of samples */
4866 int have_tRNS; /* tRNS chunk may need processing */
4867
4868 /* For checking the code calculates double precision floating point values
4869 * along with an error value, accumulated from the transforms. Because an
4870 * sBIT setting allows larger error bounds (indeed, by the spec, apparently
4871 * up to just less than +/-1 in the scaled value) the *lowest* sBIT for each
4872 * channel is stored. This sBIT value is folded in to the stored error value
4873 * at the end of the application of the transforms to the pixel.
4874 */
4875 double redf, greenf, bluef, alphaf;
4876 double rede, greene, bluee, alphae;
4877 png_byte red_sBIT, green_sBIT, blue_sBIT, alpha_sBIT;
4878} image_pixel;
4879
4880/* Shared utility function, see below. */
4881static void
4882image_pixel_setf(image_pixel *this, unsigned int max)
4883{
4884 this->redf = this->red / (double)max;
4885 this->greenf = this->green / (double)max;
4886 this->bluef = this->blue / (double)max;
4887 this->alphaf = this->alpha / (double)max;
4888
4889 if (this->red < max)
4890 this->rede = this->redf * DBL_EPSILON;
4891 else
4892 this->rede = 0;
4893 if (this->green < max)
4894 this->greene = this->greenf * DBL_EPSILON;
4895 else
4896 this->greene = 0;
4897 if (this->blue < max)
4898 this->bluee = this->bluef * DBL_EPSILON;
4899 else
4900 this->bluee = 0;
4901 if (this->alpha < max)
4902 this->alphae = this->alphaf * DBL_EPSILON;
4903 else
4904 this->alphae = 0;
4905}
4906
4907/* Initialize the structure for the next pixel - call this before doing any
4908 * transforms and call it for each pixel since all the fields may need to be
4909 * reset.
4910 */
4911static void
4912image_pixel_init(image_pixel *this, png_const_bytep row, png_byte colour_type,
4913 png_byte bit_depth, png_uint_32 x, store_palette palette)
4914{
4915 PNG_CONST png_byte sample_depth = (png_byte)(colour_type ==
4916 PNG_COLOR_TYPE_PALETTE ? 8 : bit_depth);
4917 PNG_CONST unsigned int max = (1U<<sample_depth)-1;
4918
4919 /* Initially just set everything to the same number and the alpha to opaque.
4920 * Note that this currently assumes a simple palette where entry x has colour
4921 * rgb(x,x,x)!
4922 */
4923 this->palette_index = this->red = this->green = this->blue =
4924 sample(row, colour_type, bit_depth, x, 0);
4925 this->alpha = max;
4926 this->red_sBIT = this->green_sBIT = this->blue_sBIT = this->alpha_sBIT =
4927 sample_depth;
4928
4929 /* Then override as appropriate: */
4930 if (colour_type == 3) /* palette */
4931 {
4932 /* This permits the caller to default to the sample value. */
4933 if (palette != 0)
4934 {
4935 PNG_CONST unsigned int i = this->palette_index;
4936
4937 this->red = palette[i].red;
4938 this->green = palette[i].green;
4939 this->blue = palette[i].blue;
4940 this->alpha = palette[i].alpha;
4941 }
4942 }
4943
4944 else /* not palette */
4945 {
4946 unsigned int i = 0;
4947
4948 if (colour_type & 2)
4949 {
4950 this->green = sample(row, colour_type, bit_depth, x, 1);
4951 this->blue = sample(row, colour_type, bit_depth, x, 2);
4952 i = 2;
4953 }
4954 if (colour_type & 4)
4955 this->alpha = sample(row, colour_type, bit_depth, x, ++i);
4956 }
4957
4958 /* Calculate the scaled values, these are simply the values divided by
4959 * 'max' and the error is initialized to the double precision epsilon value
4960 * from the header file.
4961 */
4962 image_pixel_setf(this, max);
4963
4964 /* Store the input information for use in the transforms - these will
4965 * modify the information.
4966 */
4967 this->colour_type = colour_type;
4968 this->bit_depth = bit_depth;
4969 this->sample_depth = sample_depth;
4970 this->have_tRNS = 0;
4971}
4972
4973/* Convert a palette image to an rgb image. This necessarily converts the tRNS
4974 * chunk at the same time, because the tRNS will be in palette form. The way
4975 * palette validation works means that the original palette is never updated,
4976 * instead the image_pixel value from the row contains the RGB of the
4977 * corresponding palette entry and *this* is updated. Consequently this routine
4978 * only needs to change the colour type information.
4979 */
4980static void
4981image_pixel_convert_PLTE(image_pixel *this)
4982{
4983 if (this->colour_type == PNG_COLOR_TYPE_PALETTE)
4984 {
4985 if (this->have_tRNS)
4986 {
4987 this->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
4988 this->have_tRNS = 0;
4989 }
4990 else
4991 this->colour_type = PNG_COLOR_TYPE_RGB;
4992
4993 /* The bit depth of the row changes at this point too (notice that this is
4994 * the row format, not the sample depth, which is separate.)
4995 */
4996 this->bit_depth = 8;
4997 }
4998}
4999
5000/* Add an alpha channel; this will import the tRNS information because tRNS is
5001 * not valid in an alpha image. The bit depth will invariably be set to at
5002 * least 8. Palette images will be converted to alpha (using the above API).
5003 */
5004static void
5005image_pixel_add_alpha(image_pixel *this, PNG_CONST standard_display *display)
5006{
5007 if (this->colour_type == PNG_COLOR_TYPE_PALETTE)
5008 image_pixel_convert_PLTE(this);
5009
5010 if ((this->colour_type & PNG_COLOR_MASK_ALPHA) == 0)
5011 {
5012 if (this->colour_type == PNG_COLOR_TYPE_GRAY)
5013 {
5014 if (this->bit_depth < 8)
5015 this->bit_depth = 8;
5016
5017 if (this->have_tRNS)
5018 {
5019 this->have_tRNS = 0;
5020
5021 /* Check the input, original, channel value here against the
5022 * original tRNS gray chunk valie.
5023 */
5024 if (this->red == display->transparent.red)
5025 this->alphaf = 0;
5026 else
5027 this->alphaf = 1;
5028 }
5029 else
5030 this->alphaf = 1;
5031
5032 this->colour_type = PNG_COLOR_TYPE_GRAY_ALPHA;
5033 }
5034
5035 else if (this->colour_type == PNG_COLOR_TYPE_RGB)
5036 {
5037 if (this->have_tRNS)
5038 {
5039 this->have_tRNS = 0;
5040
5041 /* Again, check the exact input values, not the current transformed
5042 * value!
5043 */
5044 if (this->red == display->transparent.red &&
5045 this->green == display->transparent.green &&
5046 this->blue == display->transparent.blue)
5047 this->alphaf = 0;
5048 else
5049 this->alphaf = 1;
5050
5051 this->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
5052 }
5053 }
5054
5055 /* The error in the alpha is zero and the sBIT value comes from the
5056 * original sBIT data (actually it will always be the original bit depth).
5057 */
5058 this->alphae = 0;
5059 this->alpha_sBIT = display->alpha_sBIT;
5060 }
5061}
5062
5063struct transform_display;
5064typedef struct image_transform
5065{
5066 /* The name of this transform: a string. */
5067 PNG_CONST char *name;
5068
5069 /* Each transform can be disabled from the command line: */
5070 int enable;
5071
5072 /* The global list of transforms; read only. */
5073 struct image_transform *PNG_CONST list;
5074
5075 /* The global count of the number of times this transform has been set on an
5076 * image.
5077 */
5078 unsigned int global_use;
5079
5080 /* The local count of the number of times this transform has been set. */
5081 unsigned int local_use;
5082
5083 /* The next transform in the list, each transform must call its own next
5084 * transform after it has processed the pixel successfully.
5085 */
5086 PNG_CONST struct image_transform *next;
5087
5088 /* A single transform for the image, expressed as a series of function
5089 * callbacks and some space for values.
5090 *
5091 * First a callback to add any required modifications to the png_modifier;
5092 * this gets called just before the modifier is set up for read.
5093 */
5094 void (*ini)(PNG_CONST struct image_transform *this,
5095 struct transform_display *that);
5096
5097 /* And a callback to set the transform on the current png_read_struct:
5098 */
5099 void (*set)(PNG_CONST struct image_transform *this,
5100 struct transform_display *that, png_structp pp, png_infop pi);
5101
5102 /* Then a transform that takes an input pixel in one PNG format or another
5103 * and modifies it by a pngvalid implementation of the transform (thus
5104 * duplicating the libpng intent without, we hope, duplicating the bugs
5105 * in the libpng implementation!) The png_structp is solely to allow error
5106 * reporting via png_error and png_warning.
5107 */
5108 void (*mod)(PNG_CONST struct image_transform *this, image_pixel *that,
5109 png_structp pp, PNG_CONST struct transform_display *display);
5110
5111 /* Add this transform to the list and return true if the transform is
5112 * meaningful for this colour type and bit depth - if false then the
5113 * transform should have no effect on the image so there's not a lot of
5114 * point running it.
5115 */
5116 int (*add)(struct image_transform *this,
5117 PNG_CONST struct image_transform **that, png_byte colour_type,
5118 png_byte bit_depth);
5119} image_transform;
5120
5121typedef struct transform_display
5122{
5123 standard_display this;
5124
5125 /* Parameters */
5126 png_modifier* pm;
5127 PNG_CONST image_transform* transform_list;
5128
5129 /* Local variables */
5130 png_byte output_colour_type;
5131 png_byte output_bit_depth;
5132
5133 /* Modifications (not necessarily used.) */
5134 gama_modification gama_mod;
5135 chrm_modification chrm_mod;
5136 srgb_modification srgb_mod;
5137} transform_display;
5138
5139/* Set sRGB, cHRM and gAMA transforms as required by the current encoding. */
5140static void
5141transform_set_encoding(transform_display *this)
5142{
5143 /* Set up the png_modifier '_current' fields then use these to determine how
5144 * to add appropriate chunks.
5145 */
5146 png_modifier *pm = this->pm;
5147
5148 modifier_set_encoding(pm);
5149
5150 if (modifier_color_encoding_is_set(pm))
5151 {
5152 if (modifier_color_encoding_is_sRGB(pm))
5153 srgb_modification_init(&this->srgb_mod, pm, PNG_sRGB_INTENT_ABSOLUTE);
5154
5155 else
5156 {
5157 /* Set gAMA and cHRM separately. */
5158 gama_modification_init(&this->gama_mod, pm, pm->current_gamma);
5159
5160 if (pm->current_encoding != 0)
5161 chrm_modification_init(&this->chrm_mod, pm, pm->current_encoding);
5162 }
5163 }
5164}
5165
5166/* Three functions to end the list: */
5167static void
5168image_transform_ini_end(PNG_CONST image_transform *this,
5169 transform_display *that)
5170{
5171 UNUSED(this)
5172 UNUSED(that)
5173}
5174
5175static void
5176image_transform_set_end(PNG_CONST image_transform *this,
5177 transform_display *that, png_structp pp, png_infop pi)
5178{
5179 UNUSED(this)
5180 UNUSED(that)
5181 UNUSED(pp)
5182 UNUSED(pi)
5183}
5184
5185/* At the end of the list recalculate the output image pixel value from the
5186 * double precision values set up by the preceding 'mod' calls:
5187 */
5188static unsigned int
5189sample_scale(double sample_value, unsigned int scale)
5190{
5191 sample_value = floor(sample_value * scale + .5);
5192
5193 /* Return NaN as 0: */
5194 if (!(sample_value > 0))
5195 sample_value = 0;
5196 else if (sample_value > scale)
5197 sample_value = scale;
5198
5199 return (unsigned int)sample_value;
5200}
5201
5202static void
5203image_transform_mod_end(PNG_CONST image_transform *this, image_pixel *that,
5204 png_structp pp, PNG_CONST transform_display *display)
5205{
5206 PNG_CONST unsigned int scale = (1U<<that->sample_depth)-1;
5207
5208 UNUSED(this)
5209 UNUSED(pp)
5210 UNUSED(display)
5211
5212 /* At the end recalculate the digitized red green and blue values according
5213 * to the current sample_depth of the pixel.
5214 *
5215 * The sample value is simply scaled to the maximum, checking for over
5216 * and underflow (which can both happen for some image transforms,
5217 * including simple size scaling, though libpng doesn't do that at present.
5218 */
5219 that->red = sample_scale(that->redf, scale);
5220
5221 /* The error value is increased, at the end, according to the lowest sBIT
5222 * value seen. Common sense tells us that the intermediate integer
5223 * representations are no more accurate than +/- 0.5 in the integral values,
5224 * the sBIT allows the implementation to be worse than this. In addition the
5225 * PNG specification actually permits any error within the range (-1..+1),
5226 * but that is ignored here. Instead the final digitized value is compared,
5227 * below to the digitized value of the error limits - this has the net effect
5228 * of allowing (almost) +/-1 in the output value. It's difficult to see how
5229 * any algorithm that digitizes intermediate results can be more accurate.
5230 */
5231 that->rede += 1./(2*((1U<<that->red_sBIT)-1));
5232
5233 if (that->colour_type & PNG_COLOR_MASK_COLOR)
5234 {
5235 that->green = sample_scale(that->greenf, scale);
5236 that->blue = sample_scale(that->bluef, scale);
5237 that->greene += 1./(2*((1U<<that->green_sBIT)-1));
5238 that->bluee += 1./(2*((1U<<that->blue_sBIT)-1));
5239 }
5240 else
5241 {
5242 that->blue = that->green = that->red;
5243 that->bluef = that->greenf = that->redf;
5244 that->bluee = that->greene = that->rede;
5245 }
5246
5247 if ((that->colour_type & PNG_COLOR_MASK_ALPHA) ||
5248 that->colour_type == PNG_COLOR_TYPE_PALETTE)
5249 {
5250 that->alpha = sample_scale(that->alphaf, scale);
5251 that->alphae += 1./(2*((1U<<that->alpha_sBIT)-1));
5252 }
5253 else
5254 {
5255 that->alpha = scale; /* opaque */
5256 that->alpha = 1; /* Override this. */
5257 that->alphae = 0; /* It's exact ;-) */
5258 }
5259}
5260
5261/* Static 'end' structure: */
5262static image_transform image_transform_end =
5263{
5264 "(end)", /* name */
5265 1, /* enable */
5266 0, /* list */
5267 0, /* global_use */
5268 0, /* local_use */
5269 0, /* next */
5270 image_transform_ini_end,
5271 image_transform_set_end,
5272 image_transform_mod_end,
5273 0 /* never called, I want it to crash if it is! */
5274};
5275
5276/* Reader callbacks and implementations, where they differ from the standard
5277 * ones.
5278 */
5279static void
5280transform_display_init(transform_display *dp, png_modifier *pm, png_uint_32 id,
5281 PNG_CONST image_transform *transform_list)
5282{
5283 memset(dp, 0, sizeof *dp);
5284
5285 /* Standard fields */
5286 standard_display_init(&dp->this, &pm->this, id, 0/*do_interlace*/,
5287 pm->use_update_info);
5288
5289 /* Parameter fields */
5290 dp->pm = pm;
5291 dp->transform_list = transform_list;
5292
5293 /* Local variable fields */
5294 dp->output_colour_type = 255; /* invalid */
5295 dp->output_bit_depth = 255; /* invalid */
5296}
5297
5298static void
5299transform_info_imp(transform_display *dp, png_structp pp, png_infop pi)
5300{
5301 /* Reuse the standard stuff as appropriate. */
5302 standard_info_part1(&dp->this, pp, pi);
5303
5304 /* Now set the list of transforms. */
5305 dp->transform_list->set(dp->transform_list, dp, pp, pi);
5306
5307 /* Update the info structure for these transforms: */
5308 {
5309 int i = dp->this.use_update_info;
5310 /* Always do one call, even if use_update_info is 0. */
5311 do
5312 png_read_update_info(pp, pi);
5313 while (--i > 0);
5314 }
5315
5316 /* And get the output information into the standard_display */
5317 standard_info_part2(&dp->this, pp, pi, 1/*images*/);
5318
5319 /* Plus the extra stuff we need for the transform tests: */
5320 dp->output_colour_type = png_get_color_type(pp, pi);
5321 dp->output_bit_depth = png_get_bit_depth(pp, pi);
5322
5323 /* Validate the combination of colour type and bit depth that we are getting
5324 * out of libpng; the semantics of something not in the PNG spec are, at
5325 * best, unclear.
5326 */
5327 switch (dp->output_colour_type)
5328 {
5329 case PNG_COLOR_TYPE_PALETTE:
5330 if (dp->output_bit_depth > 8) goto error;
5331 /*FALL THROUGH*/
5332 case PNG_COLOR_TYPE_GRAY:
5333 if (dp->output_bit_depth == 1 || dp->output_bit_depth == 2 ||
5334 dp->output_bit_depth == 4)
5335 break;
5336 /*FALL THROUGH*/
5337 default:
5338 if (dp->output_bit_depth == 8 || dp->output_bit_depth == 16)
5339 break;
5340 /*FALL THROUGH*/
5341 error:
5342 {
5343 char message[128];
5344 size_t pos;
5345
5346 pos = safecat(message, sizeof message, 0,
5347 "invalid final bit depth: colour type(");
5348 pos = safecatn(message, sizeof message, pos, dp->output_colour_type);
5349 pos = safecat(message, sizeof message, pos, ") with bit depth: ");
5350 pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
5351
5352 png_error(pp, message);
5353 }
5354 }
5355
5356 /* Use a test pixel to check that the output agrees with what we expect -
5357 * this avoids running the whole test if the output is unexpected.
5358 */
5359 {
5360 image_pixel test_pixel;
5361
5362 memset(&test_pixel, 0, sizeof test_pixel);
5363 test_pixel.colour_type = dp->this.colour_type; /* input */
5364 test_pixel.bit_depth = dp->this.bit_depth;
5365 if (test_pixel.colour_type == PNG_COLOR_TYPE_PALETTE)
5366 test_pixel.sample_depth = 8;
5367 else
5368 test_pixel.sample_depth = test_pixel.bit_depth;
5369 /* Don't need sBIT here, but it must be set to non-zero to avoid
5370 * arithmetic overflows.
5371 */
5372 test_pixel.have_tRNS = dp->this.is_transparent;
5373 test_pixel.red_sBIT = test_pixel.green_sBIT = test_pixel.blue_sBIT =
5374 test_pixel.alpha_sBIT = test_pixel.sample_depth;
5375
5376 dp->transform_list->mod(dp->transform_list, &test_pixel, pp, dp);
5377
5378 if (test_pixel.colour_type != dp->output_colour_type)
5379 {
5380 char message[128];
5381 size_t pos = safecat(message, sizeof message, 0, "colour type ");
5382
5383 pos = safecatn(message, sizeof message, pos, dp->output_colour_type);
5384 pos = safecat(message, sizeof message, pos, " expected ");
5385 pos = safecatn(message, sizeof message, pos, test_pixel.colour_type);
5386
5387 png_error(pp, message);
5388 }
5389
5390 if (test_pixel.bit_depth != dp->output_bit_depth)
5391 {
5392 char message[128];
5393 size_t pos = safecat(message, sizeof message, 0, "bit depth ");
5394
5395 pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
5396 pos = safecat(message, sizeof message, pos, " expected ");
5397 pos = safecatn(message, sizeof message, pos, test_pixel.bit_depth);
5398
5399 png_error(pp, message);
5400 }
5401
5402 /* If both bit depth and colour type are correct check the sample depth.
5403 * I believe these are both internal errors.
5404 */
5405 if (test_pixel.colour_type == PNG_COLOR_TYPE_PALETTE)
5406 {
5407 if (test_pixel.sample_depth != 8) /* oops - internal error! */
5408 png_error(pp, "pngvalid: internal: palette sample depth not 8");
5409 }
5410 else if (test_pixel.sample_depth != dp->output_bit_depth)
5411 {
5412 char message[128];
5413 size_t pos = safecat(message, sizeof message, 0,
5414 "internal: sample depth ");
5415
5416 pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
5417 pos = safecat(message, sizeof message, pos, " expected ");
5418 pos = safecatn(message, sizeof message, pos, test_pixel.sample_depth);
5419
5420 png_error(pp, message);
5421 }
5422 }
5423}
5424
5425static void
5426transform_info(png_structp pp, png_infop pi)
5427{
5428 transform_info_imp(voidcast(transform_display*, png_get_progressive_ptr(pp)),
5429 pp, pi);
5430}
5431
5432static void
5433transform_range_check(png_structp pp, unsigned int r, unsigned int g,
5434 unsigned int b, unsigned int a, unsigned int in_digitized, double in,
5435 unsigned int out, png_byte sample_depth, double err, double limit,
5436 PNG_CONST char *name, double digitization_error)
5437{
5438 /* Compare the scaled, digitzed, values of our local calculation (in+-err)
5439 * with the digitized values libpng produced; 'sample_depth' is the actual
5440 * digitization depth of the libpng output colors (the bit depth except for
5441 * palette images where it is always 8.) The check on 'err' is to detect
5442 * internal errors in pngvalid itself.
5443 */
5444 unsigned int max = (1U<<sample_depth)-1;
5445 double in_min = ceil((in-err)*max - digitization_error);
5446 double in_max = floor((in+err)*max + digitization_error);
5447 if (err > limit || !(out >= in_min && out <= in_max))
5448 {
5449 char message[256];
5450 size_t pos;
5451
5452 pos = safecat(message, sizeof message, 0, name);
5453 pos = safecat(message, sizeof message, pos, " output value error: rgba(");
5454 pos = safecatn(message, sizeof message, pos, r);
5455 pos = safecat(message, sizeof message, pos, ",");
5456 pos = safecatn(message, sizeof message, pos, g);
5457 pos = safecat(message, sizeof message, pos, ",");
5458 pos = safecatn(message, sizeof message, pos, b);
5459 pos = safecat(message, sizeof message, pos, ",");
5460 pos = safecatn(message, sizeof message, pos, a);
5461 pos = safecat(message, sizeof message, pos, "): ");
5462 pos = safecatn(message, sizeof message, pos, out);
5463 pos = safecat(message, sizeof message, pos, " expected: ");
5464 pos = safecatn(message, sizeof message, pos, in_digitized);
5465 pos = safecat(message, sizeof message, pos, " (");
5466 pos = safecatd(message, sizeof message, pos, (in-err)*max, 3);
5467 pos = safecat(message, sizeof message, pos, "..");
5468 pos = safecatd(message, sizeof message, pos, (in+err)*max, 3);
5469 pos = safecat(message, sizeof message, pos, ")");
5470
5471 png_error(pp, message);
5472 }
5473}
5474
5475static void
5476transform_image_validate(transform_display *dp, png_structp pp, png_infop pi)
5477{
5478 /* Constants for the loop below: */
5479 PNG_CONST png_store* PNG_CONST ps = dp->this.ps;
5480 PNG_CONST png_byte in_ct = dp->this.colour_type;
5481 PNG_CONST png_byte in_bd = dp->this.bit_depth;
5482 PNG_CONST png_uint_32 w = dp->this.w;
5483 PNG_CONST png_uint_32 h = dp->this.h;
5484 PNG_CONST png_byte out_ct = dp->output_colour_type;
5485 PNG_CONST png_byte out_bd = dp->output_bit_depth;
5486 PNG_CONST png_byte sample_depth = (png_byte)(out_ct ==
5487 PNG_COLOR_TYPE_PALETTE ? 8 : out_bd);
5488 PNG_CONST png_byte red_sBIT = dp->this.red_sBIT;
5489 PNG_CONST png_byte green_sBIT = dp->this.green_sBIT;
5490 PNG_CONST png_byte blue_sBIT = dp->this.blue_sBIT;
5491 PNG_CONST png_byte alpha_sBIT = dp->this.alpha_sBIT;
5492 PNG_CONST int have_tRNS = dp->this.is_transparent;
5493 double digitization_error;
5494
5495 store_palette out_palette;
5496 png_uint_32 y;
5497
5498 UNUSED(pi)
5499
5500 /* Check for row overwrite errors */
5501 store_image_check(dp->this.ps, pp, 0);
5502
5503 /* Read the palette corresponding to the output if the output colour type
5504 * indicates a palette, othewise set out_palette to garbage.
5505 */
5506 if (out_ct == PNG_COLOR_TYPE_PALETTE)
5507 {
5508 /* Validate that the palette count itself has not changed - this is not
5509 * expected.
5510 */
5511 int npalette = (-1);
5512
5513 (void)read_palette(out_palette, &npalette, pp, pi);
5514 if (npalette != dp->this.npalette)
5515 png_error(pp, "unexpected change in palette size");
5516
5517 digitization_error = .5;
5518 }
5519 else
5520 {
5521 png_byte in_sample_depth;
5522
5523 memset(out_palette, 0x5e, sizeof out_palette);
5524
5525 /* assume-8-bit-calculations means assume that if the input has 8 bit
5526 * (or less) samples and the output has 16 bit samples the calculations
5527 * will be done with 8 bit precision, not 16.
5528 *
5529 * TODO: fix this in libpng; png_set_expand_16 should cause 16 bit
5530 * calculations to be used throughout.
5531 */
5532 if (in_ct == PNG_COLOR_TYPE_PALETTE || in_bd < 16)
5533 in_sample_depth = 8;
5534 else
5535 in_sample_depth = in_bd;
5536
5537 if (sample_depth != 16 || in_sample_depth > 8 ||
5538 !dp->pm->calculations_use_input_precision)
5539 digitization_error = .5;
5540
5541 /* Else errors are at 8 bit precision, scale .5 in 8 bits to the 16 bits:
5542 */
5543 else
5544 digitization_error = .5 * 257;
5545 }
5546
5547 for (y=0; y<h; ++y)
5548 {
5549 png_const_bytep PNG_CONST pRow = store_image_row(ps, pp, 0, y);
5550 png_uint_32 x;
5551
5552 /* The original, standard, row pre-transforms. */
5553 png_byte std[STANDARD_ROWMAX];
5554
5555 transform_row(pp, std, in_ct, in_bd, y);
5556
5557 /* Go through each original pixel transforming it and comparing with what
5558 * libpng did to the same pixel.
5559 */
5560 for (x=0; x<w; ++x)
5561 {
5562 image_pixel in_pixel, out_pixel;
5563 unsigned int r, g, b, a;
5564
5565 /* Find out what we think the pixel should be: */
5566 image_pixel_init(&in_pixel, std, in_ct, in_bd, x, dp->this.palette);
5567
5568 in_pixel.red_sBIT = red_sBIT;
5569 in_pixel.green_sBIT = green_sBIT;
5570 in_pixel.blue_sBIT = blue_sBIT;
5571 in_pixel.alpha_sBIT = alpha_sBIT;
5572 in_pixel.have_tRNS = have_tRNS;
5573
5574 /* For error detection, below. */
5575 r = in_pixel.red;
5576 g = in_pixel.green;
5577 b = in_pixel.blue;
5578 a = in_pixel.alpha;
5579
5580 dp->transform_list->mod(dp->transform_list, &in_pixel, pp, dp);
5581
5582 /* Read the output pixel and compare it to what we got, we don't
5583 * use the error field here, so no need to update sBIT.
5584 */
5585 image_pixel_init(&out_pixel, pRow, out_ct, out_bd, x, out_palette);
5586
5587 /* We don't expect changes to the index here even if the bit depth is
5588 * changed.
5589 */
5590 if (in_ct == PNG_COLOR_TYPE_PALETTE &&
5591 out_ct == PNG_COLOR_TYPE_PALETTE)
5592 {
5593 if (in_pixel.palette_index != out_pixel.palette_index)
5594 png_error(pp, "unexpected transformed palette index");
5595 }
5596
5597 /* Check the colours for palette images too - in fact the palette could
5598 * be separately verified itself in most cases.
5599 */
5600 if (in_pixel.red != out_pixel.red)
5601 transform_range_check(pp, r, g, b, a, in_pixel.red, in_pixel.redf,
5602 out_pixel.red, sample_depth, in_pixel.rede,
5603 dp->pm->limit + 1./(2*((1U<<in_pixel.red_sBIT)-1)), "red/gray",
5604 digitization_error);
5605
5606 if ((out_ct & PNG_COLOR_MASK_COLOR) != 0 &&
5607 in_pixel.green != out_pixel.green)
5608 transform_range_check(pp, r, g, b, a, in_pixel.green,
5609 in_pixel.greenf, out_pixel.green, sample_depth, in_pixel.greene,
5610 dp->pm->limit + 1./(2*((1U<<in_pixel.green_sBIT)-1)), "green",
5611 digitization_error);
5612
5613 if ((out_ct & PNG_COLOR_MASK_COLOR) != 0 &&
5614 in_pixel.blue != out_pixel.blue)
5615 transform_range_check(pp, r, g, b, a, in_pixel.blue, in_pixel.bluef,
5616 out_pixel.blue, sample_depth, in_pixel.bluee,
5617 dp->pm->limit + 1./(2*((1U<<in_pixel.blue_sBIT)-1)), "blue",
5618 digitization_error);
5619
5620 if ((out_ct & PNG_COLOR_MASK_ALPHA) != 0 &&
5621 in_pixel.alpha != out_pixel.alpha)
5622 transform_range_check(pp, r, g, b, a, in_pixel.alpha,
5623 in_pixel.alphaf, out_pixel.alpha, sample_depth, in_pixel.alphae,
5624 dp->pm->limit + 1./(2*((1U<<in_pixel.alpha_sBIT)-1)), "alpha",
5625 digitization_error);
5626 } /* pixel (x) loop */
5627 } /* row (y) loop */
5628
5629 /* Record that something was actually checked to avoid a false positive. */
5630 dp->this.ps->validated = 1;
5631}
5632
5633static void
5634transform_end(png_structp pp, png_infop pi)
5635{
5636 transform_display *dp = voidcast(transform_display*,
5637 png_get_progressive_ptr(pp));
5638
5639 if (!dp->this.speed)
5640 transform_image_validate(dp, pp, pi);
5641 else
5642 dp->this.ps->validated = 1;
5643}
5644
5645/* A single test run. */
5646static void
5647transform_test(png_modifier *pmIn, PNG_CONST png_uint_32 idIn,
5648 PNG_CONST image_transform* transform_listIn, PNG_CONST char * volatile name)
5649{
5650 transform_display d;
5651 context(&pmIn->this, fault);
5652
5653 transform_display_init(&d, pmIn, idIn, transform_listIn);
5654
5655 Try
5656 {
5657 size_t pos = 0;
5658 png_structp pp;
5659 png_infop pi;
5660 char full_name[256];
5661
5662 /* Make sure the encoding fields are correct and enter the required
5663 * modifications.
5664 */
5665 transform_set_encoding(&d);
5666
5667 /* Add any modifications required by the transform list. */
5668 d.transform_list->ini(d.transform_list, &d);
5669
5670 /* Add the color space information, if any, to the name. */
5671 pos = safecat(full_name, sizeof full_name, pos, name);
5672 pos = safecat_current_encoding(full_name, sizeof full_name, pos, d.pm);
5673
5674 /* Get a png_struct for reading the image. */
5675 pp = set_modifier_for_read(d.pm, &pi, d.this.id, full_name);
5676 standard_palette_init(&d.this);
5677
5678# if 0
5679 /* Logging (debugging only) */
5680 {
5681 char buffer[256];
5682
5683 (void)store_message(&d.pm->this, pp, buffer, sizeof buffer, 0,
5684 "running test");
5685
5686 fprintf(stderr, "%s\n", buffer);
5687 }
5688# endif
5689
5690 /* Introduce the correct read function. */
5691 if (d.pm->this.progressive)
5692 {
5693 /* Share the row function with the standard implementation. */
5694 png_set_progressive_read_fn(pp, &d, transform_info, progressive_row,
5695 transform_end);
5696
5697 /* Now feed data into the reader until we reach the end: */
5698 modifier_progressive_read(d.pm, pp, pi);
5699 }
5700 else
5701 {
5702 /* modifier_read expects a png_modifier* */
5703 png_set_read_fn(pp, d.pm, modifier_read);
5704
5705 /* Check the header values: */
5706 png_read_info(pp, pi);
5707
5708 /* Process the 'info' requirements. Only one image is generated */
5709 transform_info_imp(&d, pp, pi);
5710
5711 sequential_row(&d.this, pp, pi, -1, 0);
5712
5713 if (!d.this.speed)
5714 transform_image_validate(&d, pp, pi);
5715 else
5716 d.this.ps->validated = 1;
5717 }
5718
5719 modifier_reset(d.pm);
5720 }
5721
5722 Catch(fault)
5723 {
5724 modifier_reset((png_modifier*)fault);
5725 }
5726}
5727
5728/* The transforms: */
5729#define ITSTRUCT(name) image_transform_##name
5730#define ITDATA(name) image_transform_data_##name
5731#define image_transform_ini image_transform_default_ini
5732#define IT(name)\
5733static image_transform ITSTRUCT(name) =\
5734{\
5735 #name,\
5736 1, /*enable*/\
5737 &PT, /*list*/\
5738 0, /*global_use*/\
5739 0, /*local_use*/\
5740 0, /*next*/\
5741 image_transform_ini,\
5742 image_transform_png_set_##name##_set,\
5743 image_transform_png_set_##name##_mod,\
5744 image_transform_png_set_##name##_add\
5745}
5746#define PT ITSTRUCT(end) /* stores the previous transform */
5747
5748/* To save code: */
5749static void
5750image_transform_default_ini(PNG_CONST image_transform *this,
5751 transform_display *that)
5752{
5753 this->next->ini(this->next, that);
5754}
5755
5756static int
5757image_transform_default_add(image_transform *this,
5758 PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
5759{
5760 UNUSED(colour_type)
5761 UNUSED(bit_depth)
5762
5763 this->next = *that;
5764 *that = this;
5765
5766 return 1;
5767}
5768
5769#ifdef PNG_READ_EXPAND_SUPPORTED
5770/* png_set_palette_to_rgb */
5771static void
5772image_transform_png_set_palette_to_rgb_set(PNG_CONST image_transform *this,
5773 transform_display *that, png_structp pp, png_infop pi)
5774{
5775 png_set_palette_to_rgb(pp);
5776 this->next->set(this->next, that, pp, pi);
5777}
5778
5779static void
5780image_transform_png_set_palette_to_rgb_mod(PNG_CONST image_transform *this,
5781 image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
5782{
5783 if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
5784 image_pixel_convert_PLTE(that);
5785
5786 this->next->mod(this->next, that, pp, display);
5787}
5788
5789static int
5790image_transform_png_set_palette_to_rgb_add(image_transform *this,
5791 PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
5792{
5793 UNUSED(bit_depth)
5794
5795 this->next = *that;
5796 *that = this;
5797
5798 return colour_type == PNG_COLOR_TYPE_PALETTE;
5799}
5800
5801IT(palette_to_rgb);
5802#undef PT
5803#define PT ITSTRUCT(palette_to_rgb)
5804#endif /* PNG_READ_EXPAND_SUPPORTED */
5805
5806#ifdef PNG_READ_EXPAND_SUPPORTED
5807/* png_set_tRNS_to_alpha */
5808static void
5809image_transform_png_set_tRNS_to_alpha_set(PNG_CONST image_transform *this,
5810 transform_display *that, png_structp pp, png_infop pi)
5811{
5812 png_set_tRNS_to_alpha(pp);
5813 this->next->set(this->next, that, pp, pi);
5814}
5815
5816static void
5817image_transform_png_set_tRNS_to_alpha_mod(PNG_CONST image_transform *this,
5818 image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
5819{
5820 /* LIBPNG BUG: this always forces palette images to RGB. */
5821 if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
5822 image_pixel_convert_PLTE(that);
5823
5824 /* This effectively does an 'expand' only if there is some transparency to
5825 * convert to an alpha channel.
5826 */
5827 if (that->have_tRNS)
5828 image_pixel_add_alpha(that, &display->this);
5829
5830 /* LIBPNG BUG: otherwise libpng still expands to 8 bits! */
5831 else
5832 {
5833 if (that->bit_depth < 8)
5834 that->bit_depth =8;
5835 if (that->sample_depth < 8)
5836 that->sample_depth = 8;
5837 }
5838
5839 this->next->mod(this->next, that, pp, display);
5840}
5841
5842static int
5843image_transform_png_set_tRNS_to_alpha_add(image_transform *this,
5844 PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
5845{
5846 UNUSED(bit_depth)
5847
5848 this->next = *that;
5849 *that = this;
5850
5851 /* We don't know yet whether there will be a tRNS chunk, but we know that
5852 * this transformation should do nothing if there already is an alpha
5853 * channel.
5854 */
5855 return (colour_type & PNG_COLOR_MASK_ALPHA) == 0;
5856}
5857
5858IT(tRNS_to_alpha);
5859#undef PT
5860#define PT ITSTRUCT(tRNS_to_alpha)
5861#endif /* PNG_READ_EXPAND_SUPPORTED */
5862
5863#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
5864/* png_set_gray_to_rgb */
5865static void
5866image_transform_png_set_gray_to_rgb_set(PNG_CONST image_transform *this,
5867 transform_display *that, png_structp pp, png_infop pi)
5868{
5869 png_set_gray_to_rgb(pp);
5870 this->next->set(this->next, that, pp, pi);
5871}
5872
5873static void
5874image_transform_png_set_gray_to_rgb_mod(PNG_CONST image_transform *this,
5875 image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
5876{
5877 /* NOTE: we can actually pend the tRNS processing at this point because we
5878 * can correctly recognize the original pixel value even though we have
5879 * mapped the one gray channel to the three RGB ones, but in fact libpng
5880 * doesn't do this, so we don't either.
5881 */
5882 if ((that->colour_type & PNG_COLOR_MASK_COLOR) == 0 && that->have_tRNS)
5883 image_pixel_add_alpha(that, &display->this);
5884
5885 /* Simply expand the bit depth and alter the colour type as required. */
5886 if (that->colour_type == PNG_COLOR_TYPE_GRAY)
5887 {
5888 /* RGB images have a bit depth at least equal to '8' */
5889 if (that->bit_depth < 8)
5890 that->sample_depth = that->bit_depth = 8;
5891
5892 /* And just changing the colour type works here because the green and blue
5893 * channels are being maintained in lock-step with the red/gray:
5894 */
5895 that->colour_type = PNG_COLOR_TYPE_RGB;
5896 }
5897
5898 else if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
5899 that->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
5900
5901 this->next->mod(this->next, that, pp, display);
5902}
5903
5904static int
5905image_transform_png_set_gray_to_rgb_add(image_transform *this,
5906 PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
5907{
5908 UNUSED(bit_depth)
5909
5910 this->next = *that;
5911 *that = this;
5912
5913 return (colour_type & PNG_COLOR_MASK_COLOR) == 0;
5914}
5915
5916IT(gray_to_rgb);
5917#undef PT
5918#define PT ITSTRUCT(gray_to_rgb)
5919#endif /* PNG_READ_GRAY_TO_RGB_SUPPORTED */
5920
5921#ifdef PNG_READ_EXPAND_SUPPORTED
5922/* png_set_expand */
5923static void
5924image_transform_png_set_expand_set(PNG_CONST image_transform *this,
5925 transform_display *that, png_structp pp, png_infop pi)
5926{
5927 png_set_expand(pp);
5928 this->next->set(this->next, that, pp, pi);
5929}
5930
5931static void
5932image_transform_png_set_expand_mod(PNG_CONST image_transform *this,
5933 image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
5934{
5935 /* The general expand case depends on what the colour type is: */
5936 if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
5937 image_pixel_convert_PLTE(that);
5938 else if (that->bit_depth < 8) /* grayscale */
5939 that->sample_depth = that->bit_depth = 8;
5940
5941 if (that->have_tRNS)
5942 image_pixel_add_alpha(that, &display->this);
5943
5944 this->next->mod(this->next, that, pp, display);
5945}
5946
5947static int
5948image_transform_png_set_expand_add(image_transform *this,
5949 PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
5950{
5951 UNUSED(bit_depth)
5952
5953 this->next = *that;
5954 *that = this;
5955
5956 /* 'expand' should do nothing for RGBA or GA input - no tRNS and the bit
5957 * depth is at least 8 already.
5958 */
5959 return (colour_type & PNG_COLOR_MASK_ALPHA) == 0;
5960}
5961
5962IT(expand);
5963#undef PT
5964#define PT ITSTRUCT(expand)
5965#endif /* PNG_READ_EXPAND_SUPPORTED */
5966
5967#ifdef PNG_READ_EXPAND_SUPPORTED
5968/* png_set_expand_gray_1_2_4_to_8
5969 * LIBPNG BUG: this just does an 'expand'
5970 */
5971static void
5972image_transform_png_set_expand_gray_1_2_4_to_8_set(
5973 PNG_CONST image_transform *this, transform_display *that, png_structp pp,
5974 png_infop pi)
5975{
5976 png_set_expand_gray_1_2_4_to_8(pp);
5977 this->next->set(this->next, that, pp, pi);
5978}
5979
5980static void
5981image_transform_png_set_expand_gray_1_2_4_to_8_mod(
5982 PNG_CONST image_transform *this, image_pixel *that, png_structp pp,
5983 PNG_CONST transform_display *display)
5984{
5985 image_transform_png_set_expand_mod(this, that, pp, display);
5986}
5987
5988static int
5989image_transform_png_set_expand_gray_1_2_4_to_8_add(image_transform *this,
5990 PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
5991{
5992 return image_transform_png_set_expand_add(this, that, colour_type,
5993 bit_depth);
5994}
5995
5996IT(expand_gray_1_2_4_to_8);
5997#undef PT
5998#define PT ITSTRUCT(expand_gray_1_2_4_to_8)
5999#endif /* PNG_READ_EXPAND_SUPPORTED */
6000
6001#ifdef PNG_READ_EXPAND_16_SUPPORTED
6002/* png_set_expand_16 */
6003static void
6004image_transform_png_set_expand_16_set(PNG_CONST image_transform *this,
6005 transform_display *that, png_structp pp, png_infop pi)
6006{
6007 png_set_expand_16(pp);
6008 this->next->set(this->next, that, pp, pi);
6009}
6010
6011static void
6012image_transform_png_set_expand_16_mod(PNG_CONST image_transform *this,
6013 image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
6014{
6015 /* Expect expand_16 to expand everything to 16 bits as a result of also
6016 * causing 'expand' to happen.
6017 */
6018 if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
6019 image_pixel_convert_PLTE(that);
6020
6021 if (that->have_tRNS)
6022 image_pixel_add_alpha(that, &display->this);
6023
6024 if (that->bit_depth < 16)
6025 that->sample_depth = that->bit_depth = 16;
6026
6027 this->next->mod(this->next, that, pp, display);
6028}
6029
6030static int
6031image_transform_png_set_expand_16_add(image_transform *this,
6032 PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
6033{
6034 UNUSED(colour_type)
6035
6036 this->next = *that;
6037 *that = this;
6038
6039 /* expand_16 does something unless the bit depth is already 16. */
6040 return bit_depth < 16;
6041}
6042
6043IT(expand_16);
6044#undef PT
6045#define PT ITSTRUCT(expand_16)
6046#endif /* PNG_READ_EXPAND_16_SUPPORTED */
6047
6048#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED /* API added in 1.5.4 */
6049/* png_set_scale_16 */
6050static void
6051image_transform_png_set_scale_16_set(PNG_CONST image_transform *this,
6052 transform_display *that, png_structp pp, png_infop pi)
6053{
6054 png_set_scale_16(pp);
6055 this->next->set(this->next, that, pp, pi);
6056}
6057
6058static void
6059image_transform_png_set_scale_16_mod(PNG_CONST image_transform *this,
6060 image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
6061{
6062 if (that->bit_depth == 16)
6063 {
6064 that->sample_depth = that->bit_depth = 8;
6065 if (that->red_sBIT > 8) that->red_sBIT = 8;
6066 if (that->green_sBIT > 8) that->green_sBIT = 8;
6067 if (that->blue_sBIT > 8) that->blue_sBIT = 8;
6068 if (that->alpha_sBIT > 8) that->alpha_sBIT = 8;
6069 }
6070
6071 this->next->mod(this->next, that, pp, display);
6072}
6073
6074static int
6075image_transform_png_set_scale_16_add(image_transform *this,
6076 PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
6077{
6078 UNUSED(colour_type)
6079
6080 this->next = *that;
6081 *that = this;
6082
6083 return bit_depth > 8;
6084}
6085
6086IT(scale_16);
6087#undef PT
6088#define PT ITSTRUCT(scale_16)
6089#endif /* PNG_READ_SCALE_16_TO_8_SUPPORTED (1.5.4 on) */
6090
6091#ifdef PNG_READ_16_TO_8_SUPPORTED /* the default before 1.5.4 */
6092/* png_set_strip_16 */
6093static void
6094image_transform_png_set_strip_16_set(PNG_CONST image_transform *this,
6095 transform_display *that, png_structp pp, png_infop pi)
6096{
6097 png_set_strip_16(pp);
6098 this->next->set(this->next, that, pp, pi);
6099}
6100
6101static void
6102image_transform_png_set_strip_16_mod(PNG_CONST image_transform *this,
6103 image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
6104{
6105 if (that->bit_depth == 16)
6106 {
6107 that->sample_depth = that->bit_depth = 8;
6108 if (that->red_sBIT > 8) that->red_sBIT = 8;
6109 if (that->green_sBIT > 8) that->green_sBIT = 8;
6110 if (that->blue_sBIT > 8) that->blue_sBIT = 8;
6111 if (that->alpha_sBIT > 8) that->alpha_sBIT = 8;
6112
6113 /* Prior to 1.5.4 png_set_strip_16 would use an 'accurate' method if this
6114 * configuration option is set. From 1.5.4 the flag is never set and the
6115 * 'scale' API (above) must be used.
6116 */
6117# ifdef PNG_READ_ACCURATE_SCALE_SUPPORTED
6118# if PNG_LIBPNG_VER >= 10504
6119# error PNG_READ_ACCURATE_SCALE should not be set
6120# endif
6121
6122 /* The strip 16 algorithm drops the low 8 bits rather than calculating
6123 * 1/257, so we need to adjust the permitted errors appropriately:
6124 * Notice that this is only relevant prior to the addition of the
6125 * png_set_scale_16 API in 1.5.4 (but 1.5.4+ always defines the above!)
6126 */
6127 {
6128 PNG_CONST double d = (255-128.5)/65535;
6129 that->rede += d;
6130 that->greene += d;
6131 that->bluee += d;
6132 that->alphae += d;
6133 }
6134# endif
6135 }
6136
6137 this->next->mod(this->next, that, pp, display);
6138}
6139
6140static int
6141image_transform_png_set_strip_16_add(image_transform *this,
6142 PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
6143{
6144 UNUSED(colour_type)
6145
6146 this->next = *that;
6147 *that = this;
6148
6149 return bit_depth > 8;
6150}
6151
6152IT(strip_16);
6153#undef PT
6154#define PT ITSTRUCT(strip_16)
6155#endif /* PNG_READ_16_TO_8_SUPPORTED */
6156
6157#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
6158/* png_set_strip_alpha */
6159static void
6160image_transform_png_set_strip_alpha_set(PNG_CONST image_transform *this,
6161 transform_display *that, png_structp pp, png_infop pi)
6162{
6163 png_set_strip_alpha(pp);
6164 this->next->set(this->next, that, pp, pi);
6165}
6166
6167static void
6168image_transform_png_set_strip_alpha_mod(PNG_CONST image_transform *this,
6169 image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
6170{
6171 if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
6172 that->colour_type = PNG_COLOR_TYPE_GRAY;
6173 else if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
6174 that->colour_type = PNG_COLOR_TYPE_RGB;
6175
6176 that->have_tRNS = 0;
6177 that->alphaf = 1;
6178
6179 this->next->mod(this->next, that, pp, display);
6180}
6181
6182static int
6183image_transform_png_set_strip_alpha_add(image_transform *this,
6184 PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
6185{
6186 UNUSED(bit_depth)
6187
6188 this->next = *that;
6189 *that = this;
6190
6191 return (colour_type & PNG_COLOR_MASK_ALPHA) != 0;
6192}
6193
6194IT(strip_alpha);
6195#undef PT
6196#define PT ITSTRUCT(strip_alpha)
6197#endif /* PNG_READ_STRIP_ALPHA_SUPPORTED */
6198
6199#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
6200/* png_set_rgb_to_gray(png_structp, int err_action, double red, double green)
6201 * png_set_rgb_to_gray_fixed(png_structp, int err_action, png_fixed_point red,
6202 * png_fixed_point green)
6203 * png_get_rgb_to_gray_status
6204 *
6205 * The 'default' test here uses values known to be used inside libpng:
6206 *
6207 * red: 6968
6208 * green: 23434
6209 * blue: 2366
6210 *
6211 * These values are being retained for compatibility, along with the somewhat
6212 * broken truncation calculation in the fast-and-inaccurate code path. Older
6213 * versions of libpng will fail the accuracy tests below because they use the
6214 * truncation algorithm everywhere.
6215 */
6216#define data ITDATA(rgb_to_gray)
6217static struct
6218{
6219 double gamma; /* File gamma to use in processing */
6220
6221 /* The following are the parameters for png_set_rgb_to_gray: */
6222# ifdef PNG_FLOATING_POINT_SUPPORTED
6223 double red_to_set;
6224 double green_to_set;
6225# else
6226 png_fixed_point red_to_set;
6227 png_fixed_point green_to_set;
6228# endif
6229
6230 /* The actual coefficients: */
6231 double red_coefficient;
6232 double green_coefficient;
6233 double blue_coefficient;
6234
6235 /* Set if the coeefficients have been overridden. */
6236 int coefficients_overridden;
6237} data;
6238
6239#undef image_transform_ini
6240#define image_transform_ini image_transform_png_set_rgb_to_gray_ini
6241static void
6242image_transform_png_set_rgb_to_gray_ini(PNG_CONST image_transform *this,
6243 transform_display *that)
6244{
6245 png_modifier *pm = that->pm;
6246 PNG_CONST color_encoding *e = pm->current_encoding;
6247
6248 UNUSED(this)
6249
6250 /* Since we check the encoding this flag must be set: */
6251 pm->test_uses_encoding = 1;
6252
6253 /* If 'e' is not NULL chromaticity information is present and either a cHRM
6254 * or an sRGB chunk will be inserted.
6255 */
6256 if (e != 0)
6257 {
6258 /* Coefficients come from the encoding, but may need to be normalized to a
6259 * white point Y of 1.0
6260 */
6261 PNG_CONST double whiteY = e->red.Y + e->green.Y + e->blue.Y;
6262
6263 data.red_coefficient = e->red.Y;
6264 data.green_coefficient = e->green.Y;
6265 data.blue_coefficient = e->blue.Y;
6266
6267 if (whiteY != 1)
6268 {
6269 data.red_coefficient /= whiteY;
6270 data.green_coefficient /= whiteY;
6271 data.blue_coefficient /= whiteY;
6272 }
6273 }
6274
6275 else
6276 {
6277 /* The default (built in) coeffcients, as above: */
6278 data.red_coefficient = 6968 / 32768.;
6279 data.green_coefficient = 23434 / 32768.;
6280 data.blue_coefficient = 2366 / 32768.;
6281 }
6282
6283 data.gamma = pm->current_gamma;
6284
6285 /* If not set then the calculations assume linear encoding (implicitly): */
6286 if (data.gamma == 0)
6287 data.gamma = 1;
6288
6289 /* The arguments to png_set_rgb_to_gray can override the coefficients implied
6290 * by the color space encoding. If doing exhaustive checks do the override
6291 * in each case, otherwise do it randomly.
6292 */
6293 if (pm->test_exhaustive)
6294 {
6295 /* First time in coefficients_overridden is 0, the following sets it to 1,
6296 * so repeat if it is set. If a test fails this may mean we subsequently
6297 * skip a non-override test, ignore that.
6298 */
6299 data.coefficients_overridden = !data.coefficients_overridden;
6300 pm->repeat = data.coefficients_overridden != 0;
6301 }
6302
6303 else
6304 data.coefficients_overridden = random_choice();
6305
6306 if (data.coefficients_overridden)
6307 {
6308 /* These values override the color encoding defaults, simply use random
6309 * numbers.
6310 */
6311 png_uint_32 ru;
6312 double total;
6313
6314 RANDOMIZE(ru);
6315 data.green_coefficient = total = (ru & 0xffff) / 65535.;
6316 ru >>= 16;
6317 data.red_coefficient = (1 - total) * (ru & 0xffff) / 65535.;
6318 total += data.red_coefficient;
6319 data.blue_coefficient = 1 - total;
6320
6321# ifdef PNG_FLOATING_POINT_SUPPORTED
6322 data.red_to_set = data.red_coefficient;
6323 data.green_to_set = data.green_coefficient;
6324# else
6325 data.red_to_set = fix(data.red_coefficient);
6326 data.green_to_set = fix(data.green_coefficient);
6327# endif
6328
6329 /* The following just changes the error messages: */
6330 pm->encoding_ignored = 1;
6331 }
6332
6333 else
6334 {
6335 data.red_to_set = -1;
6336 data.green_to_set = -1;
6337 }
6338
6339 /* Adjust the error limit in the png_modifier because of the larger errors
6340 * produced in the digitization during the gamma handling.
6341 */
6342 if (data.gamma != 1) /* Use gamma tables */
6343 {
6344 if (that->this.bit_depth == 16 || pm->assume_16_bit_calculations)
6345 {
6346 /* The 16 bit case ends up producing a maximum error of about
6347 * +/-5 in 65535, allow for +/-8 with the given gamma.
6348 */
6349 that->pm->limit += pow(8./65535, data.gamma);
6350 }
6351
6352 else
6353 {
6354 /* Rounding to 8 bits in the linear space causes massive errors which
6355 * will trigger the error check in transform_range_check. Fix that
6356 * here by taking the gamma encoding into account.
6357 */
6358 that->pm->limit += pow(1./255, data.gamma);
6359 }
6360 }
6361
6362 else
6363 {
6364 /* With no gamma correction a large error comes from the truncation of the
6365 * calculation in the 8 bit case, allow for that here.
6366 */
6367 if (that->this.bit_depth != 16)
6368 that->pm->limit += 4E-3;
6369 }
6370}
6371
6372static void
6373image_transform_png_set_rgb_to_gray_set(PNG_CONST image_transform *this,
6374 transform_display *that, png_structp pp, png_infop pi)
6375{
6376 PNG_CONST int error_action = 1; /* no error, no defines in png.h */
6377
6378# ifdef PNG_FLOATING_POINT_SUPPORTED
6379 png_set_rgb_to_gray(pp, error_action, data.red_to_set, data.green_to_set);
6380# else
6381 png_set_rgb_to_gray_fixed(pp, error_action, data.red_to_set,
6382 data.green_to_set);
6383# endif
6384
6385# ifdef PNG_READ_cHRM_SUPPORTED
6386 if (that->pm->current_encoding != 0)
6387 {
6388 /* We have an encoding so a cHRM chunk may have been set; if so then
6389 * check that the libpng APIs give the correct (X,Y,Z) values within
6390 * some margin of error for the round trip through the chromaticity
6391 * form.
6392 */
6393# ifdef PNG_FLOATING_POINT_SUPPORTED
6394# define API_function png_get_cHRM_XYZ
6395# define API_form "FP"
6396# define API_type double
6397# define API_cvt(x) (x)
6398# else
6399# define API_function png_get_cHRM_XYZ_fixed
6400# define API_form "fixed"
6401# define API_type png_fixed_point
6402# define API_cvt(x) ((double)(x)/PNG_FP_1)
6403# endif
6404
6405 API_type rX, gX, bX;
6406 API_type rY, gY, bY;
6407 API_type rZ, gZ, bZ;
6408
6409 if ((API_function(pp, pi, &rX, &rY, &rZ, &gX, &gY, &gZ, &bX, &bY, &bZ)
6410 & PNG_INFO_cHRM) != 0)
6411 {
6412 double maxe;
6413 PNG_CONST char *el;
6414 color_encoding e, o;
6415
6416 /* Expect libpng to return a normalized result, but the original
6417 * color space encoding may not be normalized.
6418 */
6419 modifier_current_encoding(that->pm, &o);
6420 normalize_color_encoding(&o);
6421
6422 /* Sanity check the pngvalid code - the coefficients should match
6423 * the normalized Y values of the encoding unless they were
6424 * overridden.
6425 */
6426 if (data.red_to_set == -1 && data.green_to_set == -1 &&
6427 (fabs(o.red.Y - data.red_coefficient) > DBL_EPSILON ||
6428 fabs(o.green.Y - data.green_coefficient) > DBL_EPSILON ||
6429 fabs(o.blue.Y - data.blue_coefficient) > DBL_EPSILON))
6430 png_error(pp, "internal pngvalid cHRM coefficient error");
6431
6432 /* Generate a colour space encoding. */
6433 e.gamma = o.gamma; /* not used */
6434 e.red.X = API_cvt(rX);
6435 e.red.Y = API_cvt(rY);
6436 e.red.Z = API_cvt(rZ);
6437 e.green.X = API_cvt(gX);
6438 e.green.Y = API_cvt(gY);
6439 e.green.Z = API_cvt(gZ);
6440 e.blue.X = API_cvt(bX);
6441 e.blue.Y = API_cvt(bY);
6442 e.blue.Z = API_cvt(bZ);
6443
6444 /* This should match the original one from the png_modifier, within
6445 * the range permitted by the libpng fixed point representation.
6446 */
6447 maxe = 0;
6448 el = "-"; /* Set to element name with error */
6449
6450# define CHECK(col,x)\
6451 {\
6452 double err = fabs(o.col.x - e.col.x);\
6453 if (err > maxe)\
6454 {\
6455 maxe = err;\
6456 el = #col "(" #x ")";\
6457 }\
6458 }
6459
6460 CHECK(red,X)
6461 CHECK(red,Y)
6462 CHECK(red,Z)
6463 CHECK(green,X)
6464 CHECK(green,Y)
6465 CHECK(green,Z)
6466 CHECK(blue,X)
6467 CHECK(blue,Y)
6468 CHECK(blue,Z)
6469
6470 /* Here in both fixed and floating cases to check the values read
6471 * from the cHRm chunk. PNG uses fixed point in the cHRM chunk, so
6472 * we can't expect better than +/-.5E-5 on the result, allow 1E-5.
6473 */
6474 if (maxe >= 1E-5)
6475 {
6476 size_t pos = 0;
6477 char buffer[256];
6478
6479 pos = safecat(buffer, sizeof buffer, pos, API_form);
6480 pos = safecat(buffer, sizeof buffer, pos, " cHRM ");
6481 pos = safecat(buffer, sizeof buffer, pos, el);
6482 pos = safecat(buffer, sizeof buffer, pos, " error: ");
6483 pos = safecatd(buffer, sizeof buffer, pos, maxe, 7);
6484 pos = safecat(buffer, sizeof buffer, pos, " ");
6485 /* Print the color space without the gamma value: */
6486 pos = safecat_color_encoding(buffer, sizeof buffer, pos, &o, 0);
6487 pos = safecat(buffer, sizeof buffer, pos, " -> ");
6488 pos = safecat_color_encoding(buffer, sizeof buffer, pos, &e, 0);
6489
6490 png_error(pp, buffer);
6491 }
6492 }
6493 }
6494# endif /* READ_cHRM */
6495
6496 this->next->set(this->next, that, pp, pi);
6497}
6498
6499static void
6500image_transform_png_set_rgb_to_gray_mod(PNG_CONST image_transform *this,
6501 image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
6502{
6503 if ((that->colour_type & PNG_COLOR_MASK_COLOR) != 0)
6504 {
6505 double gray, err;
6506
6507 if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
6508 image_pixel_convert_PLTE(that);
6509
6510 /* Image now has RGB channels... */
6511 {
6512 PNG_CONST png_modifier *pm = display->pm;
6513 PNG_CONST unsigned int sample_depth = that->sample_depth;
6514 int isgray;
6515 double r, g, b;
6516 double rlo, rhi, glo, ghi, blo, bhi, graylo, grayhi;
6517
6518 /* Do this using interval arithmetic, otherwise it is too difficult to
6519 * handle the errors correctly.
6520 *
6521 * To handle the gamma correction work out the upper and lower bounds
6522 * of the digitized value. Assume rounding here - normally the values
6523 * will be identical after this operation if there is only one
6524 * transform, feel free to delete the png_error checks on this below in
6525 * the future (this is just me trying to ensure it works!)
6526 */
6527 r = rlo = rhi = that->redf;
6528 rlo -= that->rede;
6529 rlo = digitize(pm, rlo, sample_depth, 1/*round*/);
6530 rhi += that->rede;
6531 rhi = digitize(pm, rhi, sample_depth, 1/*round*/);
6532
6533 g = glo = ghi = that->greenf;
6534 glo -= that->greene;
6535 glo = digitize(pm, glo, sample_depth, 1/*round*/);
6536 ghi += that->greene;
6537 ghi = digitize(pm, ghi, sample_depth, 1/*round*/);
6538
6539 b = blo = bhi = that->bluef;
6540 blo -= that->bluee;
6541 blo = digitize(pm, blo, sample_depth, 1/*round*/);
6542 bhi += that->greene;
6543 bhi = digitize(pm, bhi, sample_depth, 1/*round*/);
6544
6545 isgray = r==g && g==b;
6546
6547 if (data.gamma != 1)
6548 {
6549 PNG_CONST double power = 1/data.gamma;
6550 PNG_CONST double abse = abserr(pm, sample_depth, sample_depth);
6551
6552 /* 'abse' is the absolute error permitted in linear calculations. It
6553 * is used here to capture the error permitted in the handling
6554 * (undoing) of the gamma encoding. Once again digitization occurs
6555 * to handle the upper and lower bounds of the values. This is
6556 * where the real errors are introduced.
6557 */
6558 r = pow(r, power);
6559 rlo = digitize(pm, pow(rlo, power)-abse, sample_depth, 1);
6560 rhi = digitize(pm, pow(rhi, power)+abse, sample_depth, 1);
6561
6562 g = pow(g, power);
6563 glo = digitize(pm, pow(glo, power)-abse, sample_depth, 1);
6564 ghi = digitize(pm, pow(ghi, power)+abse, sample_depth, 1);
6565
6566 b = pow(b, power);
6567 blo = digitize(pm, pow(blo, power)-abse, sample_depth, 1);
6568 bhi = digitize(pm, pow(bhi, power)+abse, sample_depth, 1);
6569 }
6570
6571 /* Now calculate the actual gray values. Although the error in the
6572 * coefficients depends on whether they were specified on the command
6573 * line (in which case truncation to 15 bits happened) or not (rounding
6574 * was used) the maxium error in an individual coefficient is always
6575 * 1/32768, because even in the rounding case the requirement that
6576 * coefficients add up to 32768 can cause a larger rounding error.
6577 *
6578 * The only time when rounding doesn't occur in 1.5.5 and later is when
6579 * the non-gamma code path is used for less than 16 bit data.
6580 */
6581 gray = r * data.red_coefficient + g * data.green_coefficient +
6582 b * data.blue_coefficient;
6583
6584 {
6585 PNG_CONST int do_round = data.gamma != 1 || sample_depth == 16;
6586 PNG_CONST double ce = 1. / 32768;
6587
6588 graylo = digitize(pm, rlo * (data.red_coefficient-ce) +
6589 glo * (data.green_coefficient-ce) +
6590 blo * (data.blue_coefficient-ce), sample_depth, do_round);
6591 if (graylo <= 0)
6592 graylo = 0;
6593
6594 grayhi = digitize(pm, rhi * (data.red_coefficient+ce) +
6595 ghi * (data.green_coefficient+ce) +
6596 bhi * (data.blue_coefficient+ce), sample_depth, do_round);
6597 if (grayhi >= 1)
6598 grayhi = 1;
6599 }
6600
6601 /* And invert the gamma. */
6602 if (data.gamma != 1)
6603 {
6604 PNG_CONST double power = data.gamma;
6605
6606 gray = pow(gray, power);
6607 graylo = digitize(pm, pow(graylo, power), sample_depth, 1);
6608 grayhi = digitize(pm, pow(grayhi, power), sample_depth, 1);
6609 }
6610
6611 /* Now the error can be calculated.
6612 *
6613 * If r==g==b because there is no overall gamma correction libpng
6614 * currently preserves the original value.
6615 */
6616 if (isgray)
6617 err = (that->rede + that->greene + that->bluee)/3;
6618
6619 else
6620 {
6621 err = fabs(grayhi-gray);
6622 if (fabs(gray - graylo) > err)
6623 err = fabs(graylo-gray);
6624
6625 /* Check that this worked: */
6626 if (err > display->pm->limit)
6627 {
6628 size_t pos = 0;
6629 char buffer[128];
6630
6631 pos = safecat(buffer, sizeof buffer, pos, "rgb_to_gray error ");
6632 pos = safecatd(buffer, sizeof buffer, pos, err, 6);
6633 pos = safecat(buffer, sizeof buffer, pos, " exceeds limit ");
6634 pos = safecatd(buffer, sizeof buffer, pos,
6635 display->pm->limit, 6);
6636 png_error(pp, buffer);
6637 }
6638 }
6639 }
6640
6641 that->bluef = that->greenf = that->redf = gray;
6642 that->bluee = that->greene = that->rede = err;
6643
6644 /* The sBIT is the minium of the three colour channel sBITs. */
6645 if (that->red_sBIT > that->green_sBIT)
6646 that->red_sBIT = that->green_sBIT;
6647 if (that->red_sBIT > that->blue_sBIT)
6648 that->red_sBIT = that->blue_sBIT;
6649 that->blue_sBIT = that->green_sBIT = that->red_sBIT;
6650
6651 /* And remove the colour bit in the type: */
6652 if (that->colour_type == PNG_COLOR_TYPE_RGB)
6653 that->colour_type = PNG_COLOR_TYPE_GRAY;
6654 else if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
6655 that->colour_type = PNG_COLOR_TYPE_GRAY_ALPHA;
6656 }
6657
6658 this->next->mod(this->next, that, pp, display);
6659}
6660
6661static int
6662image_transform_png_set_rgb_to_gray_add(image_transform *this,
6663 PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
6664{
6665 UNUSED(bit_depth)
6666
6667 this->next = *that;
6668 *that = this;
6669
6670 return (colour_type & PNG_COLOR_MASK_COLOR) != 0;
6671}
6672
6673#undef data
6674IT(rgb_to_gray);
6675#undef PT
6676#define PT ITSTRUCT(rgb_to_gray)
6677#undef image_transform_ini
6678#define image_transform_ini image_transform_default_ini
6679#endif /* PNG_READ_RGB_TO_GRAY_SUPPORTED */
6680
6681#ifdef PNG_READ_BACKGROUND_SUPPORTED
6682/* png_set_background(png_structp, png_const_color_16p background_color,
6683 * int background_gamma_code, int need_expand, double background_gamma)
6684 * png_set_background_fixed(png_structp, png_const_color_16p background_color,
6685 * int background_gamma_code, int need_expand,
6686 * png_fixed_point background_gamma)
6687 *
6688 * As with rgb_to_gray this ignores the gamma (at present.)
6689*/
6690#define data ITDATA(background)
6691static image_pixel data;
6692
6693static void
6694image_transform_png_set_background_set(PNG_CONST image_transform *this,
6695 transform_display *that, png_structp pp, png_infop pi)
6696{
6697 png_byte colour_type, bit_depth;
6698 png_byte random_bytes[8]; /* 8 bytes - 64 bits - the biggest pixel */
6699 png_color_16 back;
6700
6701 /* We need a background colour, because we don't know exactly what transforms
6702 * have been set we have to supply the colour in the original file format and
6703 * so we need to know what that is! The background colour is stored in the
6704 * transform_display.
6705 */
6706 RANDOMIZE(random_bytes);
6707
6708 /* Read the random value, for colour type 3 the background colour is actually
6709 * expressed as a 24bit rgb, not an index.
6710 */
6711 colour_type = that->this.colour_type;
6712 if (colour_type == 3)
6713 {
6714 colour_type = PNG_COLOR_TYPE_RGB;
6715 bit_depth = 8;
6716 }
6717
6718 else
6719 bit_depth = that->this.bit_depth;
6720
6721 image_pixel_init(&data, random_bytes, colour_type,
6722 bit_depth, 0/*x*/, 0/*unused: palette*/);
6723
6724 /* Extract the background colour from this image_pixel, but make sure the
6725 * unused fields of 'back' are garbage.
6726 */
6727 RANDOMIZE(back);
6728
6729 if (colour_type & PNG_COLOR_MASK_COLOR)
6730 {
6731 back.red = (png_uint_16)data.red;
6732 back.green = (png_uint_16)data.green;
6733 back.blue = (png_uint_16)data.blue;
6734 }
6735
6736 else
6737 back.gray = (png_uint_16)data.red;
6738
6739# ifdef PNG_FLOATING_POINT_SUPPORTED
6740 png_set_background(pp, &back, PNG_BACKGROUND_GAMMA_FILE, 1/*need expand*/,
6741 0);
6742# else
6743 png_set_background_fixed(pp, &back, PNG_BACKGROUND_GAMMA_FILE,
6744 1/*need expand*/, 0);
6745# endif
6746
6747 this->next->set(this->next, that, pp, pi);
6748}
6749
6750static void
6751image_transform_png_set_background_mod(PNG_CONST image_transform *this,
6752 image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
6753{
6754 /* Check for tRNS first: */
6755 if (that->have_tRNS && that->colour_type != PNG_COLOR_TYPE_PALETTE)
6756 image_pixel_add_alpha(that, &display->this);
6757
6758 /* This is only necessary if the alpha value is less than 1. */
6759 if (that->alphaf < 1)
6760 {
6761 /* Now we do the background calculation without any gamma correction. */
6762 if (that->alphaf <= 0)
6763 {
6764 that->redf = data.redf;
6765 that->greenf = data.greenf;
6766 that->bluef = data.bluef;
6767
6768 that->rede = data.rede;
6769 that->greene = data.greene;
6770 that->bluee = data.bluee;
6771
6772 that->red_sBIT= data.red_sBIT;
6773 that->green_sBIT= data.green_sBIT;
6774 that->blue_sBIT= data.blue_sBIT;
6775 }
6776
6777 else /* 0 < alpha < 1 */
6778 {
6779 double alf = 1 - that->alphaf;
6780
6781 that->redf = that->redf * that->alphaf + data.redf * alf;
6782 that->rede = that->rede * that->alphaf + data.rede * alf +
6783 DBL_EPSILON;
6784 that->greenf = that->greenf * that->alphaf + data.greenf * alf;
6785 that->greene = that->greene * that->alphaf + data.greene * alf +
6786 DBL_EPSILON;
6787 that->bluef = that->bluef * that->alphaf + data.bluef * alf;
6788 that->bluee = that->bluee * that->alphaf + data.bluee * alf +
6789 DBL_EPSILON;
6790 }
6791
6792 /* Remove the alpha type and set the alpha (not in that order.) */
6793 that->alphaf = 1;
6794 that->alphae = 0;
6795
6796 if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
6797 that->colour_type = PNG_COLOR_TYPE_RGB;
6798 else if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
6799 that->colour_type = PNG_COLOR_TYPE_GRAY;
6800 /* PNG_COLOR_TYPE_PALETTE is not changed */
6801 }
6802
6803 this->next->mod(this->next, that, pp, display);
6804}
6805
6806#define image_transform_png_set_background_add image_transform_default_add
6807
6808#undef data
6809IT(background);
6810#undef PT
6811#define PT ITSTRUCT(background)
6812#endif /* PNG_READ_BACKGROUND_SUPPORTED */
6813
6814/* This may just be 'end' if all the transforms are disabled! */
6815static image_transform *PNG_CONST image_transform_first = &PT;
6816
6817static void
6818transform_enable(PNG_CONST char *name)
6819{
6820 /* Everything starts out enabled, so if we see an 'enable' disabled
6821 * everything else the first time round.
6822 */
6823 static int all_disabled = 0;
6824 int found_it = 0;
6825 image_transform *list = image_transform_first;
6826
6827 while (list != &image_transform_end)
6828 {
6829 if (strcmp(list->name, name) == 0)
6830 {
6831 list->enable = 1;
6832 found_it = 1;
6833 }
6834 else if (!all_disabled)
6835 list->enable = 0;
6836
6837 list = list->list;
6838 }
6839
6840 all_disabled = 1;
6841
6842 if (!found_it)
6843 {
6844 fprintf(stderr, "pngvalid: --transform-enable=%s: unknown transform\n",
6845 name);
6846 exit(1);
6847 }
6848}
6849
6850static void
6851transform_disable(PNG_CONST char *name)
6852{
6853 image_transform *list = image_transform_first;
6854
6855 while (list != &image_transform_end)
6856 {
6857 if (strcmp(list->name, name) == 0)
6858 {
6859 list->enable = 0;
6860 return;
6861 }
6862
6863 list = list->list;
6864 }
6865
6866 fprintf(stderr, "pngvalid: --transform-disable=%s: unknown transform\n",
6867 name);
6868 exit(1);
6869}
6870
6871static void
6872image_transform_reset_count(void)
6873{
6874 image_transform *next = image_transform_first;
6875 int count = 0;
6876
6877 while (next != &image_transform_end)
6878 {
6879 next->local_use = 0;
6880 next->next = 0;
6881 next = next->list;
6882 ++count;
6883 }
6884
6885 /* This can only happen if we every have more than 32 transforms (excluding
6886 * the end) in the list.
6887 */
6888 if (count > 32) abort();
6889}
6890
6891static int
6892image_transform_test_counter(png_uint_32 counter, unsigned int max)
6893{
6894 /* Test the list to see if there is any point contining, given a current
6895 * counter and a 'max' value.
6896 */
6897 image_transform *next = image_transform_first;
6898
6899 while (next != &image_transform_end)
6900 {
6901 /* For max 0 or 1 continue until the counter overflows: */
6902 counter >>= 1;
6903
6904 /* Continue if any entry hasn't reacked the max. */
6905 if (max > 1 && next->local_use < max)
6906 return 1;
6907 next = next->list;
6908 }
6909
6910 return max <= 1 && counter == 0;
6911}
6912
6913static png_uint_32
6914image_transform_add(PNG_CONST image_transform **this, unsigned int max,
6915 png_uint_32 counter, char *name, size_t sizeof_name, size_t *pos,
6916 png_byte colour_type, png_byte bit_depth)
6917{
6918 for (;;) /* until we manage to add something */
6919 {
6920 png_uint_32 mask;
6921 image_transform *list;
6922
6923 /* Find the next counter value, if the counter is zero this is the start
6924 * of the list. This routine always returns the current counter (not the
6925 * next) so it returns 0 at the end and expects 0 at the beginning.
6926 */
6927 if (counter == 0) /* first time */
6928 {
6929 image_transform_reset_count();
6930 if (max <= 1)
6931 counter = 1;
6932 else
6933 counter = random_32();
6934 }
6935 else /* advance the counter */
6936 {
6937 switch (max)
6938 {
6939 case 0: ++counter; break;
6940 case 1: counter <<= 1; break;
6941 default: counter = random_32(); break;
6942 }
6943 }
6944
6945 /* Now add all these items, if possible */
6946 *this = &image_transform_end;
6947 list = image_transform_first;
6948 mask = 1;
6949
6950 /* Go through the whole list adding anything that the counter selects: */
6951 while (list != &image_transform_end)
6952 {
6953 if ((counter & mask) != 0 && list->enable &&
6954 (max == 0 || list->local_use < max))
6955 {
6956 /* Candidate to add: */
6957 if (list->add(list, this, colour_type, bit_depth) || max == 0)
6958 {
6959 /* Added, so add to the name too. */
6960 *pos = safecat(name, sizeof_name, *pos, " +");
6961 *pos = safecat(name, sizeof_name, *pos, list->name);
6962 }
6963
6964 else
6965 {
6966 /* Not useful and max>0, so remove it from *this: */
6967 *this = list->next;
6968 list->next = 0;
6969
6970 /* And, since we know it isn't useful, stop it being added again
6971 * in this run:
6972 */
6973 list->local_use = max;
6974 }
6975 }
6976
6977 mask <<= 1;
6978 list = list->list;
6979 }
6980
6981 /* Now if anything was added we have something to do. */
6982 if (*this != &image_transform_end)
6983 return counter;
6984
6985 /* Nothing added, but was there anything in there to add? */
6986 if (!image_transform_test_counter(counter, max))
6987 return 0;
6988 }
6989}
6990
6991#ifdef THIS_IS_THE_PROFORMA
6992static void
6993image_transform_png_set_@_set(PNG_CONST image_transform *this,
6994 transform_display *that, png_structp pp, png_infop pi)
6995{
6996 png_set_@(pp);
6997 this->next->set(this->next, that, pp, pi);
6998}
6999
7000static void
7001image_transform_png_set_@_mod(PNG_CONST image_transform *this,
7002 image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
7003{
7004 this->next->mod(this->next, that, pp, display);
7005}
7006
7007static int
7008image_transform_png_set_@_add(image_transform *this,
7009 PNG_CONST image_transform **that, char *name, size_t sizeof_name,
7010 size_t *pos, png_byte colour_type, png_byte bit_depth)
7011{
7012 this->next = *that;
7013 *that = this;
7014
7015 *pos = safecat(name, sizeof_name, *pos, " +@");
7016
7017 return 1;
7018}
7019
7020IT(@);
7021#endif
7022
7023/* png_set_quantize(png_structp, png_colorp palette, int num_palette,
7024 * int maximum_colors, png_const_uint_16p histogram, int full_quantize)
7025 *
7026 * Very difficult to validate this!
7027 */
7028/*NOTE: TBD NYI */
7029
7030/* The data layout transforms are handled by swapping our own channel data,
7031 * necessarily these need to happen at the end of the transform list because the
7032 * semantic of the channels changes after these are executed. Some of these,
7033 * like set_shift and set_packing, can't be done at present because they change
7034 * the layout of the data at the sub-sample level so sample() won't get the
7035 * right answer.
7036 */
7037/* png_set_invert_alpha */
7038/*NOTE: TBD NYI */
7039
7040/* png_set_bgr */
7041/*NOTE: TBD NYI */
7042
7043/* png_set_swap_alpha */
7044/*NOTE: TBD NYI */
7045
7046/* png_set_swap */
7047/*NOTE: TBD NYI */
7048
7049/* png_set_filler, (png_structp png_ptr, png_uint_32 filler, int flags)); */
7050/*NOTE: TBD NYI */
7051
7052/* png_set_add_alpha, (png_structp png_ptr, png_uint_32 filler, int flags)); */
7053/*NOTE: TBD NYI */
7054
7055/* png_set_packing */
7056/*NOTE: TBD NYI */
7057
7058/* png_set_packswap */
7059/*NOTE: TBD NYI */
7060
7061/* png_set_invert_mono */
7062/*NOTE: TBD NYI */
7063
7064/* png_set_shift(png_structp, png_const_color_8p true_bits) */
7065/*NOTE: TBD NYI */
7066
7067static void
7068perform_transform_test(png_modifier *pm)
7069{
7070 png_byte colour_type = 0;
7071 png_byte bit_depth = 0;
7072 int palette_number = 0;
7073
7074 while (next_format(&colour_type, &bit_depth, &palette_number))
7075 {
7076 png_uint_32 counter = 0;
7077 size_t base_pos;
7078 char name[64];
7079
7080 base_pos = safecat(name, sizeof name, 0, "transform:");
7081
7082 for (;;)
7083 {
7084 size_t pos = base_pos;
7085 PNG_CONST image_transform *list = 0;
7086
7087 /* 'max' is currently hardwired to '1'; this should be settable on the
7088 * command line.
7089 */
7090 counter = image_transform_add(&list, 1/*max*/, counter,
7091 name, sizeof name, &pos, colour_type, bit_depth);
7092
7093 if (counter == 0)
7094 break;
7095
7096 /* The command line can change this to checking interlaced images. */
7097 do
7098 {
7099 pm->repeat = 0;
7100 transform_test(pm, FILEID(colour_type, bit_depth, palette_number,
7101 pm->interlace_type, 0, 0, 0), list, name);
7102
7103 if (fail(pm))
7104 return;
7105 }
7106 while (pm->repeat);
7107 }
7108 }
7109}
7110#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
7111
7112/********************************* GAMMA TESTS ********************************/
7113#ifdef PNG_READ_GAMMA_SUPPORTED
7114/* Reader callbacks and implementations, where they differ from the standard
7115 * ones.
7116 */
7117typedef struct gamma_display
7118{
7119 standard_display this;
7120
7121 /* Parameters */
7122 png_modifier* pm;
7123 double file_gamma;
7124 double screen_gamma;
7125 double background_gamma;
7126 png_byte sbit;
7127 int threshold_test;
7128 int use_input_precision;
7129 int scale16;
7130 int expand16;
7131 int do_background;
7132 png_color_16 background_color;
7133
7134 /* Local variables */
7135 double maxerrout;
7136 double maxerrpc;
7137 double maxerrabs;
7138} gamma_display;
7139
7140#define ALPHA_MODE_OFFSET 4
7141
7142static void
7143gamma_display_init(gamma_display *dp, png_modifier *pm, png_uint_32 id,
7144 double file_gamma, double screen_gamma, png_byte sbit, int threshold_test,
7145 int use_input_precision, int scale16, int expand16,
7146 int do_background, PNG_CONST png_color_16 *pointer_to_the_background_color,
7147 double background_gamma)
7148{
7149 /* Standard fields */
7150 standard_display_init(&dp->this, &pm->this, id, 0/*do_interlace*/,
7151 pm->use_update_info);
7152
7153 /* Parameter fields */
7154 dp->pm = pm;
7155 dp->file_gamma = file_gamma;
7156 dp->screen_gamma = screen_gamma;
7157 dp->background_gamma = background_gamma;
7158 dp->sbit = sbit;
7159 dp->threshold_test = threshold_test;
7160 dp->use_input_precision = use_input_precision;
7161 dp->scale16 = scale16;
7162 dp->expand16 = expand16;
7163 dp->do_background = do_background;
7164 if (do_background && pointer_to_the_background_color != 0)
7165 dp->background_color = *pointer_to_the_background_color;
7166 else
7167 memset(&dp->background_color, 0, sizeof dp->background_color);
7168
7169 /* Local variable fields */
7170 dp->maxerrout = dp->maxerrpc = dp->maxerrabs = 0;
7171}
7172
7173static void
7174gamma_info_imp(gamma_display *dp, png_structp pp, png_infop pi)
7175{
7176 /* Reuse the standard stuff as appropriate. */
7177 standard_info_part1(&dp->this, pp, pi);
7178
7179 /* If requested strip 16 to 8 bits - this is handled automagically below
7180 * because the output bit depth is read from the library. Note that there
7181 * are interactions with sBIT but, internally, libpng makes sbit at most
7182 * PNG_MAX_GAMMA_8 when doing the following.
7183 */
7184 if (dp->scale16)
7185# ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
7186 png_set_scale_16(pp);
7187# else
7188 /* The following works both in 1.5.4 and earlier versions: */
7189# ifdef PNG_READ_16_TO_8_SUPPORTED
7190 png_set_strip_16(pp);
7191# else
7192 png_error(pp, "scale16 (16 to 8 bit conversion) not supported");
7193# endif
7194# endif
7195
7196 if (dp->expand16)
7197# ifdef PNG_READ_EXPAND_16_SUPPORTED
7198 png_set_expand_16(pp);
7199# else
7200 png_error(pp, "expand16 (8 to 16 bit conversion) not supported");
7201# endif
7202
7203 if (dp->do_background >= ALPHA_MODE_OFFSET)
7204 {
7205# ifdef PNG_READ_ALPHA_MODE_SUPPORTED
7206 {
7207 /* This tests the alpha mode handling, if supported. */
7208 int mode = dp->do_background - ALPHA_MODE_OFFSET;
7209
7210 /* The gamma value is the output gamma, and is in the standard,
7211 * non-inverted, represenation. It provides a default for the PNG file
7212 * gamma, but since the file has a gAMA chunk this does not matter.
7213 */
7214 PNG_CONST double sg = dp->screen_gamma;
7215# ifndef PNG_FLOATING_POINT_SUPPORTED
7216 PNG_CONST png_fixed_point g = fix(sg);
7217# endif
7218
7219# ifdef PNG_FLOATING_POINT_SUPPORTED
7220 png_set_alpha_mode(pp, mode, sg);
7221# else
7222 png_set_alpha_mode_fixed(pp, mode, g);
7223# endif
7224
7225 /* However, for the standard Porter-Duff algorithm the output defaults
7226 * to be linear, so if the test requires non-linear output it must be
7227 * corrected here.
7228 */
7229 if (mode == PNG_ALPHA_STANDARD && sg != 1)
7230 {
7231# ifdef PNG_FLOATING_POINT_SUPPORTED
7232 png_set_gamma(pp, sg, dp->file_gamma);
7233# else
7234 png_fixed_point f = fix(dp->file_gamma);
7235 png_set_gamma_fixed(pp, g, f);
7236# endif
7237 }
7238 }
7239# else
7240 png_error(pp, "alpha mode handling not supported");
7241# endif
7242 }
7243
7244 else
7245 {
7246 /* Set up gamma processing. */
7247# ifdef PNG_FLOATING_POINT_SUPPORTED
7248 png_set_gamma(pp, dp->screen_gamma, dp->file_gamma);
7249# else
7250 {
7251 png_fixed_point s = fix(dp->screen_gamma);
7252 png_fixed_point f = fix(dp->file_gamma);
7253 png_set_gamma_fixed(pp, s, f);
7254 }
7255# endif
7256
7257 if (dp->do_background)
7258 {
7259# ifdef PNG_READ_BACKGROUND_SUPPORTED
7260 /* NOTE: this assumes the caller provided the correct background gamma!
7261 */
7262 PNG_CONST double bg = dp->background_gamma;
7263# ifndef PNG_FLOATING_POINT_SUPPORTED
7264 PNG_CONST png_fixed_point g = fix(bg);
7265# endif
7266
7267# ifdef PNG_FLOATING_POINT_SUPPORTED
7268 png_set_background(pp, &dp->background_color, dp->do_background,
7269 0/*need_expand*/, bg);
7270# else
7271 png_set_background_fixed(pp, &dp->background_color,
7272 dp->do_background, 0/*need_expand*/, g);
7273# endif
7274# else
7275 png_error(pp, "png_set_background not supported");
7276# endif
7277 }
7278 }
7279
7280 {
7281 int i = dp->this.use_update_info;
7282 /* Always do one call, even if use_update_info is 0. */
7283 do
7284 png_read_update_info(pp, pi);
7285 while (--i > 0);
7286 }
7287
7288 /* Now we may get a different cbRow: */
7289 standard_info_part2(&dp->this, pp, pi, 1 /*images*/);
7290}
7291
7292static void
7293gamma_info(png_structp pp, png_infop pi)
7294{
7295 gamma_info_imp(voidcast(gamma_display*, png_get_progressive_ptr(pp)), pp,
7296 pi);
7297}
7298
7299/* Validate a single component value - the routine gets the input and output
7300 * sample values as unscaled PNG component values along with a cache of all the
7301 * information required to validate the values.
7302 */
7303typedef struct validate_info
7304{
7305 png_structp pp;
7306 gamma_display *dp;
7307 png_byte sbit;
7308 int use_input_precision;
7309 int do_background;
7310 int scale16;
7311 unsigned int sbit_max;
7312 unsigned int isbit_shift;
7313 unsigned int outmax;
7314
7315 double gamma_correction; /* Overall correction required. */
7316 double file_inverse; /* Inverse of file gamma. */
7317 double screen_gamma;
7318 double screen_inverse; /* Inverse of screen gamma. */
7319
7320 double background_red; /* Linear background value, red or gray. */
7321 double background_green;
7322 double background_blue;
7323
7324 double maxabs;
7325 double maxpc;
7326 double maxcalc;
7327 double maxout;
7328 double maxout_total; /* Total including quantization error */
7329 double outlog;
7330 int outquant;
7331}
7332validate_info;
7333
7334static void
7335init_validate_info(validate_info *vi, gamma_display *dp, png_struct *pp,
7336 int in_depth, int out_depth)
7337{
7338 PNG_CONST unsigned int outmax = (1U<<out_depth)-1;
7339
7340 vi->pp = pp;
7341 vi->dp = dp;
7342
7343 if (dp->sbit > 0 && dp->sbit < in_depth)
7344 {
7345 vi->sbit = dp->sbit;
7346 vi->isbit_shift = in_depth - dp->sbit;
7347 }
7348
7349 else
7350 {
7351 vi->sbit = (png_byte)in_depth;
7352 vi->isbit_shift = 0;
7353 }
7354
7355 vi->sbit_max = (1U << vi->sbit)-1;
7356
7357 /* This mimics the libpng threshold test, '0' is used to prevent gamma
7358 * correction in the validation test.
7359 */
7360 vi->screen_gamma = dp->screen_gamma;
7361 if (fabs(vi->screen_gamma-1) < PNG_GAMMA_THRESHOLD)
7362 vi->screen_gamma = vi->screen_inverse = 0;
7363 else
7364 vi->screen_inverse = 1/vi->screen_gamma;
7365
7366 vi->use_input_precision = dp->use_input_precision;
7367 vi->outmax = outmax;
7368 vi->maxabs = abserr(dp->pm, in_depth, out_depth);
7369 vi->maxpc = pcerr(dp->pm, in_depth, out_depth);
7370 vi->maxcalc = calcerr(dp->pm, in_depth, out_depth);
7371 vi->maxout = outerr(dp->pm, in_depth, out_depth);
7372 vi->outquant = output_quantization_factor(dp->pm, in_depth, out_depth);
7373 vi->maxout_total = vi->maxout + vi->outquant * .5;
7374 vi->outlog = outlog(dp->pm, in_depth, out_depth);
7375
7376 if ((dp->this.colour_type & PNG_COLOR_MASK_ALPHA) != 0 ||
7377 (dp->this.colour_type == 3 && dp->this.is_transparent))
7378 {
7379 vi->do_background = dp->do_background;
7380
7381 if (vi->do_background != 0)
7382 {
7383 PNG_CONST double bg_inverse = 1/dp->background_gamma;
7384 double r, g, b;
7385
7386 /* Caller must at least put the gray value into the red channel */
7387 r = dp->background_color.red; r /= outmax;
7388 g = dp->background_color.green; g /= outmax;
7389 b = dp->background_color.blue; b /= outmax;
7390
7391# if 0
7392 /* libpng doesn't do this optimization, if we do pngvalid will fail.
7393 */
7394 if (fabs(bg_inverse-1) >= PNG_GAMMA_THRESHOLD)
7395# endif
7396 {
7397 r = pow(r, bg_inverse);
7398 g = pow(g, bg_inverse);
7399 b = pow(b, bg_inverse);
7400 }
7401
7402 vi->background_red = r;
7403 vi->background_green = g;
7404 vi->background_blue = b;
7405 }
7406 }
7407 else
7408 vi->do_background = 0;
7409
7410 if (vi->do_background == 0)
7411 vi->background_red = vi->background_green = vi->background_blue = 0;
7412
7413 vi->gamma_correction = 1/(dp->file_gamma*dp->screen_gamma);
7414 if (fabs(vi->gamma_correction-1) < PNG_GAMMA_THRESHOLD)
7415 vi->gamma_correction = 0;
7416
7417 vi->file_inverse = 1/dp->file_gamma;
7418 if (fabs(vi->file_inverse-1) < PNG_GAMMA_THRESHOLD)
7419 vi->file_inverse = 0;
7420
7421 vi->scale16 = dp->scale16;
7422}
7423
7424/* This function handles composition of a single non-alpha component. The
7425 * argument is the input sample value, in the range 0..1, and the alpha value.
7426 * The result is the composed, linear, input sample. If alpha is less than zero
7427 * this is the alpha component and the function should not be called!
7428 */
7429static double
7430gamma_component_compose(int do_background, double input_sample, double alpha,
7431 double background, int *compose)
7432{
7433 switch (do_background)
7434 {
7435 case PNG_BACKGROUND_GAMMA_SCREEN:
7436 case PNG_BACKGROUND_GAMMA_FILE:
7437 case PNG_BACKGROUND_GAMMA_UNIQUE:
7438 /* Standard PNG background processing. */
7439 if (alpha < 1)
7440 {
7441 if (alpha > 0)
7442 {
7443 input_sample = input_sample * alpha + background * (1-alpha);
7444 if (compose != NULL)
7445 *compose = 1;
7446 }
7447
7448 else
7449 input_sample = background;
7450 }
7451 break;
7452
7453#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
7454 case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
7455 case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
7456 /* The components are premultiplied in either case and the output is
7457 * gamma encoded (to get standard Porter-Duff we expect the output
7458 * gamma to be set to 1.0!)
7459 */
7460 case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
7461 /* The optimization is that the partial-alpha entries are linear
7462 * while the opaque pixels are gamma encoded, but this only affects the
7463 * output encoding.
7464 */
7465 if (alpha < 1)
7466 {
7467 if (alpha > 0)
7468 {
7469 input_sample *= alpha;
7470 if (compose != NULL)
7471 *compose = 1;
7472 }
7473
7474 else
7475 input_sample = 0;
7476 }
7477 break;
7478#endif
7479
7480 default:
7481 /* Standard cases where no compositing is done (so the component
7482 * value is already correct.)
7483 */
7484 break;
7485 }
7486
7487 return input_sample;
7488}
7489
7490/* This API returns the encoded *input* component, in the range 0..1 */
7491static double
7492gamma_component_validate(PNG_CONST char *name, PNG_CONST validate_info *vi,
7493 PNG_CONST unsigned int id, PNG_CONST unsigned int od,
7494 PNG_CONST double alpha /* <0 for the alpha channel itself */,
7495 PNG_CONST double background /* component background value */)
7496{
7497 PNG_CONST unsigned int isbit = id >> vi->isbit_shift;
7498 PNG_CONST unsigned int sbit_max = vi->sbit_max;
7499 PNG_CONST unsigned int outmax = vi->outmax;
7500 PNG_CONST int do_background = vi->do_background;
7501
7502 double i;
7503
7504 /* First check on the 'perfect' result obtained from the digitized input
7505 * value, id, and compare this against the actual digitized result, 'od'.
7506 * 'i' is the input result in the range 0..1:
7507 */
7508 i = isbit; i /= sbit_max;
7509
7510 /* Check for the fast route: if we don't do any background composition or if
7511 * this is the alpha channel ('alpha' < 0) or if the pixel is opaque then
7512 * just use the gamma_correction field to correct to the final output gamma.
7513 */
7514 if (alpha == 1 /* opaque pixel component */ || !do_background
7515#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
7516 || do_background == ALPHA_MODE_OFFSET + PNG_ALPHA_PNG
7517#endif
7518 || (alpha < 0 /* alpha channel */
7519#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
7520 && do_background != ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN
7521#endif
7522 ))
7523 {
7524 /* Then get the gamma corrected version of 'i' and compare to 'od', any
7525 * error less than .5 is insignificant - just quantization of the output
7526 * value to the nearest digital value (nevertheless the error is still
7527 * recorded - it's interesting ;-)
7528 */
7529 double encoded_sample = i;
7530 double encoded_error;
7531
7532 /* alpha less than 0 indicates the alpha channel, which is always linear
7533 */
7534 if (alpha >= 0 && vi->gamma_correction > 0)
7535 encoded_sample = pow(encoded_sample, vi->gamma_correction);
7536 encoded_sample *= outmax;
7537
7538 encoded_error = fabs(od-encoded_sample);
7539
7540 if (encoded_error > vi->dp->maxerrout)
7541 vi->dp->maxerrout = encoded_error;
7542
7543 if (encoded_error < vi->maxout_total && encoded_error < vi->outlog)
7544 return i;
7545 }
7546
7547 /* The slow route - attempt to do linear calculations. */
7548 /* There may be an error, or background processing is required, so calculate
7549 * the actual sample values - unencoded light intensity values. Note that in
7550 * practice these are not completely unencoded because they include a
7551 * 'viewing correction' to decrease or (normally) increase the perceptual
7552 * contrast of the image. There's nothing we can do about this - we don't
7553 * know what it is - so assume the unencoded value is perceptually linear.
7554 */
7555 {
7556 double input_sample = i; /* In range 0..1 */
7557 double output, error, encoded_sample, encoded_error;
7558 double es_lo, es_hi;
7559 int compose = 0; /* Set to one if composition done */
7560 int output_is_encoded; /* Set if encoded to screen gamma */
7561 int log_max_error = 1; /* Check maximum error values */
7562 png_const_charp pass = 0; /* Reason test passes (or 0 for fail) */
7563
7564 /* Convert to linear light (with the above caveat.) The alpha channel is
7565 * already linear.
7566 */
7567 if (alpha >= 0)
7568 {
7569 int tcompose;
7570
7571 if (vi->file_inverse > 0)
7572 input_sample = pow(input_sample, vi->file_inverse);
7573
7574 /* Handle the compose processing: */
7575 tcompose = 0;
7576 input_sample = gamma_component_compose(do_background, input_sample,
7577 alpha, background, &tcompose);
7578
7579 if (tcompose)
7580 compose = 1;
7581 }
7582
7583 /* And similarly for the output value, but we need to check the background
7584 * handling to linearize it correctly.
7585 */
7586 output = od;
7587 output /= outmax;
7588
7589 output_is_encoded = vi->screen_gamma > 0;
7590
7591 if (alpha < 0) /* The alpha channel */
7592 {
7593#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
7594 if (do_background != ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN)
7595#endif
7596 {
7597 /* In all other cases the output alpha channel is linear already,
7598 * don't log errors here, they are much larger in linear data.
7599 */
7600 output_is_encoded = 0;
7601 log_max_error = 0;
7602 }
7603 }
7604
7605#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
7606 else /* A component */
7607 {
7608 if (do_background == ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED &&
7609 alpha < 1) /* the optimized case - linear output */
7610 {
7611 if (alpha > 0) log_max_error = 0;
7612 output_is_encoded = 0;
7613 }
7614 }
7615#endif
7616
7617 if (output_is_encoded)
7618 output = pow(output, vi->screen_gamma);
7619
7620 /* Calculate (or recalculate) the encoded_sample value and repeat the
7621 * check above (unnecessary if we took the fast route, but harmless.)
7622 */
7623 encoded_sample = input_sample;
7624 if (output_is_encoded)
7625 encoded_sample = pow(encoded_sample, vi->screen_inverse);
7626 encoded_sample *= outmax;
7627
7628 encoded_error = fabs(od-encoded_sample);
7629
7630 /* Don't log errors in the alpha channel, or the 'optimized' case,
7631 * neither are significant to the overall perception.
7632 */
7633 if (log_max_error && encoded_error > vi->dp->maxerrout)
7634 vi->dp->maxerrout = encoded_error;
7635
7636 if (encoded_error < vi->maxout_total)
7637 {
7638 if (encoded_error < vi->outlog)
7639 return i;
7640
7641 /* Test passed but error is bigger than the log limit, record why the
7642 * test passed:
7643 */
7644 pass = "less than maxout:\n";
7645 }
7646
7647 /* i: the original input value in the range 0..1
7648 *
7649 * pngvalid calculations:
7650 * input_sample: linear result; i linearized and composed, range 0..1
7651 * encoded_sample: encoded result; input_sample scaled to ouput bit depth
7652 *
7653 * libpng calculations:
7654 * output: linear result; od scaled to 0..1 and linearized
7655 * od: encoded result from libpng
7656 */
7657
7658 /* Now we have the numbers for real errors, both absolute values as as a
7659 * percentage of the correct value (output):
7660 */
7661 error = fabs(input_sample-output);
7662
7663 if (log_max_error && error > vi->dp->maxerrabs)
7664 vi->dp->maxerrabs = error;
7665
7666 /* The following is an attempt to ignore the tendency of quantization to
7667 * dominate the percentage errors for lower result values:
7668 */
7669 if (log_max_error && input_sample > .5)
7670 {
7671 double percentage_error = error/input_sample;
7672 if (percentage_error > vi->dp->maxerrpc)
7673 vi->dp->maxerrpc = percentage_error;
7674 }
7675
7676 /* Now calculate the digitization limits for 'encoded_sample' using the
7677 * 'max' values. Note that maxout is in the encoded space but maxpc and
7678 * maxabs are in linear light space.
7679 *
7680 * First find the maximum error in linear light space, range 0..1:
7681 */
7682 {
7683 double tmp = input_sample * vi->maxpc;
7684 if (tmp < vi->maxabs) tmp = vi->maxabs;
7685 /* If 'compose' is true the composition was done in linear space using
7686 * integer arithmetic. This introduces an extra error of +/- 0.5 (at
7687 * least) in the integer space used. 'maxcalc' records this, taking
7688 * into account the possibility that even for 16 bit output 8 bit space
7689 * may have been used.
7690 */
7691 if (compose && tmp < vi->maxcalc) tmp = vi->maxcalc;
7692
7693 /* The 'maxout' value refers to the encoded result, to compare with
7694 * this encode input_sample adjusted by the maximum error (tmp) above.
7695 */
7696 es_lo = encoded_sample - vi->maxout;
7697
7698 if (es_lo > 0 && input_sample-tmp > 0)
7699 {
7700 double low_value = input_sample-tmp;
7701 if (output_is_encoded)
7702 low_value = pow(low_value, vi->screen_inverse);
7703 low_value *= outmax;
7704 if (low_value < es_lo) es_lo = low_value;
7705
7706 /* Quantize this appropriately: */
7707 es_lo = ceil(es_lo / vi->outquant - .5) * vi->outquant;
7708 }
7709
7710 else
7711 es_lo = 0;
7712
7713 es_hi = encoded_sample + vi->maxout;
7714
7715 if (es_hi < outmax && input_sample+tmp < 1)
7716 {
7717 double high_value = input_sample+tmp;
7718 if (output_is_encoded)
7719 high_value = pow(high_value, vi->screen_inverse);
7720 high_value *= outmax;
7721 if (high_value > es_hi) es_hi = high_value;
7722
7723 es_hi = floor(es_hi / vi->outquant + .5) * vi->outquant;
7724 }
7725
7726 else
7727 es_hi = outmax;
7728 }
7729
7730 /* The primary test is that the final encoded value returned by the
7731 * library should be between the two limits (inclusive) that were
7732 * calculated above.
7733 */
7734 if (od >= es_lo && od <= es_hi)
7735 {
7736 /* The value passes, but we may need to log the information anyway. */
7737 if (encoded_error < vi->outlog)
7738 return i;
7739
7740 if (pass == 0)
7741 pass = "within digitization limits:\n";
7742 }
7743
7744 {
7745 /* There has been an error in processing, or we need to log this
7746 * value.
7747 */
7748 double is_lo, is_hi;
7749
7750 /* pass is set at this point if either of the tests above would have
7751 * passed. Don't do these additional tests here - just log the
7752 * original [es_lo..es_hi] values.
7753 */
7754 if (pass == 0 && vi->use_input_precision)
7755 {
7756 /* Ok, something is wrong - this actually happens in current libpng
7757 * 16-to-8 processing. Assume that the input value (id, adjusted
7758 * for sbit) can be anywhere between value-.5 and value+.5 - quite a
7759 * large range if sbit is low.
7760 */
7761 double tmp = (isbit - .5)/sbit_max;
7762
7763 if (tmp <= 0)
7764 tmp = 0;
7765
7766 else if (alpha >= 0 && vi->file_inverse > 0 && tmp < 1)
7767 tmp = pow(tmp, vi->file_inverse);
7768
7769 tmp = gamma_component_compose(do_background, tmp, alpha, background,
7770 NULL);
7771
7772 if (output_is_encoded && tmp > 0 && tmp < 1)
7773 tmp = pow(tmp, vi->screen_inverse);
7774
7775 is_lo = ceil(outmax * tmp - vi->maxout_total);
7776
7777 if (is_lo < 0)
7778 is_lo = 0;
7779
7780 tmp = (isbit + .5)/sbit_max;
7781
7782 if (tmp <= 0)
7783 tmp = 0;
7784
7785 else if (alpha >= 0 && vi->file_inverse > 0 && tmp < 1)
7786 tmp = pow(tmp, vi->file_inverse);
7787
7788 tmp = gamma_component_compose(do_background, tmp, alpha, background,
7789 NULL);
7790
7791 if (output_is_encoded && tmp > 0 && tmp < 1)
7792 tmp = pow(tmp, vi->screen_inverse);
7793
7794 is_hi = floor(outmax * tmp + vi->maxout_total);
7795
7796 if (is_hi > outmax)
7797 is_hi = outmax;
7798
7799 if (!(od < is_lo || od > is_hi))
7800 {
7801 if (encoded_error < vi->outlog)
7802 return i;
7803
7804 pass = "within input precision limits:\n";
7805 }
7806
7807 /* One last chance. If this is an alpha channel and the 16to8
7808 * option has been used and 'inaccurate' scaling is used then the
7809 * bit reduction is obtained by simply using the top 8 bits of the
7810 * value.
7811 *
7812 * This is only done for older libpng versions when the 'inaccurate'
7813 * (chop) method of scaling was used.
7814 */
7815# ifndef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
7816# if PNG_LIBPNG_VER < 10504
7817 /* This may be required for other components in the future,
7818 * but at present the presence of gamma correction effectively
7819 * prevents the errors in the component scaling (I don't quite
7820 * understand why, but since it's better this way I care not
7821 * to ask, JB 20110419.)
7822 */
7823 if (pass == 0 && alpha < 0 && vi->scale16 && vi->sbit > 8 &&
7824 vi->sbit + vi->isbit_shift == 16)
7825 {
7826 tmp = ((id >> 8) - .5)/255;
7827
7828 if (tmp > 0)
7829 {
7830 is_lo = ceil(outmax * tmp - vi->maxout_total);
7831 if (is_lo < 0) is_lo = 0;
7832 }
7833
7834 else
7835 is_lo = 0;
7836
7837 tmp = ((id >> 8) + .5)/255;
7838
7839 if (tmp < 1)
7840 {
7841 is_hi = floor(outmax * tmp + vi->maxout_total);
7842 if (is_hi > outmax) is_hi = outmax;
7843 }
7844
7845 else
7846 is_hi = outmax;
7847
7848 if (!(od < is_lo || od > is_hi))
7849 {
7850 if (encoded_error < vi->outlog)
7851 return i;
7852
7853 pass = "within 8 bit limits:\n";
7854 }
7855 }
7856# endif
7857# endif
7858 }
7859 else /* !use_input_precision */
7860 is_lo = es_lo, is_hi = es_hi;
7861
7862 /* Attempt to output a meaningful error/warning message: the message
7863 * output depends on the background/composite operation being performed
7864 * because this changes what parameters were actually used above.
7865 */
7866 {
7867 size_t pos = 0;
7868 /* Need either 1/255 or 1/65535 precision here; 3 or 6 decimal
7869 * places. Just use outmax to work out which.
7870 */
7871 int precision = (outmax >= 1000 ? 6 : 3);
7872 int use_input=1, use_background=0, do_compose=0;
7873 char msg[256];
7874
7875 if (pass != 0)
7876 pos = safecat(msg, sizeof msg, pos, "\n\t");
7877
7878 /* Set up the various flags, the output_is_encoded flag above
7879 * is also used below. do_compose is just a double check.
7880 */
7881 switch (do_background)
7882 {
7883 case PNG_BACKGROUND_GAMMA_SCREEN:
7884 case PNG_BACKGROUND_GAMMA_FILE:
7885 case PNG_BACKGROUND_GAMMA_UNIQUE:
7886 use_background = (alpha >= 0 && alpha < 1);
7887 /*FALL THROUGH*/
7888# ifdef PNG_READ_ALPHA_MODE_SUPPORTED
7889 case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
7890 case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
7891 case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
7892# endif /* ALPHA_MODE_SUPPORTED */
7893 do_compose = (alpha > 0 && alpha < 1);
7894 use_input = (alpha != 0);
7895 break;
7896
7897 default:
7898 break;
7899 }
7900
7901 /* Check the 'compose' flag */
7902 if (compose != do_compose)
7903 png_error(vi->pp, "internal error (compose)");
7904
7905 /* 'name' is the component name */
7906 pos = safecat(msg, sizeof msg, pos, name);
7907 pos = safecat(msg, sizeof msg, pos, "(");
7908 pos = safecatn(msg, sizeof msg, pos, id);
7909 if (use_input || pass != 0/*logging*/)
7910 {
7911 if (isbit != id)
7912 {
7913 /* sBIT has reduced the precision of the input: */
7914 pos = safecat(msg, sizeof msg, pos, ", sbit(");
7915 pos = safecatn(msg, sizeof msg, pos, vi->sbit);
7916 pos = safecat(msg, sizeof msg, pos, "): ");
7917 pos = safecatn(msg, sizeof msg, pos, isbit);
7918 }
7919 pos = safecat(msg, sizeof msg, pos, "/");
7920 /* The output is either "id/max" or "id sbit(sbit): isbit/max" */
7921 pos = safecatn(msg, sizeof msg, pos, vi->sbit_max);
7922 }
7923 pos = safecat(msg, sizeof msg, pos, ")");
7924
7925 /* A component may have been multiplied (in linear space) by the
7926 * alpha value, 'compose' says whether this is relevant.
7927 */
7928 if (compose || pass != 0)
7929 {
7930 /* If any form of composition is being done report our
7931 * calculated linear value here (the code above doesn't record
7932 * the input value before composition is performed, so what
7933 * gets reported is the value after composition.)
7934 */
7935 if (use_input || pass != 0)
7936 {
7937 if (vi->file_inverse > 0)
7938 {
7939 pos = safecat(msg, sizeof msg, pos, "^");
7940 pos = safecatd(msg, sizeof msg, pos, vi->file_inverse, 2);
7941 }
7942
7943 else
7944 pos = safecat(msg, sizeof msg, pos, "[linear]");
7945
7946 pos = safecat(msg, sizeof msg, pos, "*(alpha)");
7947 pos = safecatd(msg, sizeof msg, pos, alpha, precision);
7948 }
7949
7950 /* Now record the *linear* background value if it was used
7951 * (this function is not passed the original, non-linear,
7952 * value but it is contained in the test name.)
7953 */
7954 if (use_background)
7955 {
7956 pos = safecat(msg, sizeof msg, pos, use_input ? "+" : " ");
7957 pos = safecat(msg, sizeof msg, pos, "(background)");
7958 pos = safecatd(msg, sizeof msg, pos, background, precision);
7959 pos = safecat(msg, sizeof msg, pos, "*");
7960 pos = safecatd(msg, sizeof msg, pos, 1-alpha, precision);
7961 }
7962 }
7963
7964 /* Report the calculated value (input_sample) and the linearized
7965 * libpng value (output) unless this is just a component gamma
7966 * correction.
7967 */
7968 if (compose || alpha < 0 || pass != 0)
7969 {
7970 pos = safecat(msg, sizeof msg, pos,
7971 pass != 0 ? " =\n\t" : " = ");
7972 pos = safecatd(msg, sizeof msg, pos, input_sample, precision);
7973 pos = safecat(msg, sizeof msg, pos, " (libpng: ");
7974 pos = safecatd(msg, sizeof msg, pos, output, precision);
7975 pos = safecat(msg, sizeof msg, pos, ")");
7976
7977 /* Finally report the output gamma encoding, if any. */
7978 if (output_is_encoded)
7979 {
7980 pos = safecat(msg, sizeof msg, pos, " ^");
7981 pos = safecatd(msg, sizeof msg, pos, vi->screen_inverse, 2);
7982 pos = safecat(msg, sizeof msg, pos, "(to screen) =");
7983 }
7984
7985 else
7986 pos = safecat(msg, sizeof msg, pos, " [screen is linear] =");
7987 }
7988
7989 if ((!compose && alpha >= 0) || pass != 0)
7990 {
7991 if (pass != 0) /* logging */
7992 pos = safecat(msg, sizeof msg, pos, "\n\t[overall:");
7993
7994 /* This is the non-composition case, the internal linear
7995 * values are irrelevant (though the log below will reveal
7996 * them.) Output a much shorter warning/error message and report
7997 * the overall gamma correction.
7998 */
7999 if (vi->gamma_correction > 0)
8000 {
8001 pos = safecat(msg, sizeof msg, pos, " ^");
8002 pos = safecatd(msg, sizeof msg, pos, vi->gamma_correction, 2);
8003 pos = safecat(msg, sizeof msg, pos, "(gamma correction) =");
8004 }
8005
8006 else
8007 pos = safecat(msg, sizeof msg, pos,
8008 " [no gamma correction] =");
8009
8010 if (pass != 0)
8011 pos = safecat(msg, sizeof msg, pos, "]");
8012 }
8013
8014 /* This is our calculated encoded_sample which should (but does
8015 * not) match od:
8016 */
8017 pos = safecat(msg, sizeof msg, pos, pass != 0 ? "\n\t" : " ");
8018 pos = safecatd(msg, sizeof msg, pos, is_lo, 1);
8019 pos = safecat(msg, sizeof msg, pos, " < ");
8020 pos = safecatd(msg, sizeof msg, pos, encoded_sample, 1);
8021 pos = safecat(msg, sizeof msg, pos, " (libpng: ");
8022 pos = safecatn(msg, sizeof msg, pos, od);
8023 pos = safecat(msg, sizeof msg, pos, ")");
8024 pos = safecat(msg, sizeof msg, pos, "/");
8025 pos = safecatn(msg, sizeof msg, pos, outmax);
8026 pos = safecat(msg, sizeof msg, pos, " < ");
8027 pos = safecatd(msg, sizeof msg, pos, is_hi, 1);
8028
8029 if (pass == 0) /* The error condition */
8030 {
8031# ifdef PNG_WARNINGS_SUPPORTED
8032 png_warning(vi->pp, msg);
8033# else
8034 store_warning(vi->pp, msg);
8035# endif
8036 }
8037
8038 else /* logging this value */
8039 store_verbose(&vi->dp->pm->this, vi->pp, pass, msg);
8040 }
8041 }
8042 }
8043
8044 return i;
8045}
8046
8047static void
8048gamma_image_validate(gamma_display *dp, png_structp pp, png_infop pi)
8049{
8050 /* Get some constants derived from the input and output file formats: */
8051 PNG_CONST png_store* PNG_CONST ps = dp->this.ps;
8052 PNG_CONST png_byte in_ct = dp->this.colour_type;
8053 PNG_CONST png_byte in_bd = dp->this.bit_depth;
8054 PNG_CONST png_uint_32 w = dp->this.w;
8055 PNG_CONST png_uint_32 h = dp->this.h;
8056 PNG_CONST size_t cbRow = dp->this.cbRow;
8057 PNG_CONST png_byte out_ct = png_get_color_type(pp, pi);
8058 PNG_CONST png_byte out_bd = png_get_bit_depth(pp, pi);
8059
8060 /* There are three sources of error, firstly the quantization in the
8061 * file encoding, determined by sbit and/or the file depth, secondly
8062 * the output (screen) gamma and thirdly the output file encoding.
8063 *
8064 * Since this API receives the screen and file gamma in double
8065 * precision it is possible to calculate an exact answer given an input
8066 * pixel value. Therefore we assume that the *input* value is exact -
8067 * sample/maxsample - calculate the corresponding gamma corrected
8068 * output to the limits of double precision arithmetic and compare with
8069 * what libpng returns.
8070 *
8071 * Since the library must quantize the output to 8 or 16 bits there is
8072 * a fundamental limit on the accuracy of the output of +/-.5 - this
8073 * quantization limit is included in addition to the other limits
8074 * specified by the paramaters to the API. (Effectively, add .5
8075 * everywhere.)
8076 *
8077 * The behavior of the 'sbit' paramter is defined by section 12.5
8078 * (sample depth scaling) of the PNG spec. That section forces the
8079 * decoder to assume that the PNG values have been scaled if sBIT is
8080 * present:
8081 *
8082 * png-sample = floor( input-sample * (max-out/max-in) + .5);
8083 *
8084 * This means that only a subset of the possible PNG values should
8085 * appear in the input. However, the spec allows the encoder to use a
8086 * variety of approximations to the above and doesn't require any
8087 * restriction of the values produced.
8088 *
8089 * Nevertheless the spec requires that the upper 'sBIT' bits of the
8090 * value stored in a PNG file be the original sample bits.
8091 * Consequently the code below simply scales the top sbit bits by
8092 * (1<<sbit)-1 to obtain an original sample value.
8093 *
8094 * Because there is limited precision in the input it is arguable that
8095 * an acceptable result is any valid result from input-.5 to input+.5.
8096 * The basic tests below do not do this, however if 'use_input_precision'
8097 * is set a subsequent test is performed below.
8098 */
8099 PNG_CONST unsigned int samples_per_pixel = (out_ct & 2U) ? 3U : 1U;
8100 int processing;
8101 png_uint_32 y;
8102 PNG_CONST store_palette_entry *in_palette = dp->this.palette;
8103 PNG_CONST int in_is_transparent = dp->this.is_transparent;
8104 int out_npalette = -1;
8105 int out_is_transparent = 0; /* Just refers to the palette case */
8106 store_palette out_palette;
8107 validate_info vi;
8108
8109 /* Check for row overwrite errors */
8110 store_image_check(dp->this.ps, pp, 0);
8111
8112 /* Supply the input and output sample depths here - 8 for an indexed image,
8113 * otherwise the bit depth.
8114 */
8115 init_validate_info(&vi, dp, pp, in_ct==3?8:in_bd, out_ct==3?8:out_bd);
8116
8117 processing = (vi.gamma_correction > 0 && !dp->threshold_test)
8118 || in_bd != out_bd || in_ct != out_ct || vi.do_background;
8119
8120 /* TODO: FIX THIS: MAJOR BUG! If the transformations all happen inside
8121 * the palette there is no way of finding out, because libpng fails to
8122 * update the palette on png_read_update_info. Indeed, libpng doesn't
8123 * even do the required work until much later, when it doesn't have any
8124 * info pointer. Oops. For the moment 'processing' is turned off if
8125 * out_ct is palette.
8126 */
8127 if (in_ct == 3 && out_ct == 3)
8128 processing = 0;
8129
8130 if (processing && out_ct == 3)
8131 out_is_transparent = read_palette(out_palette, &out_npalette, pp, pi);
8132
8133 for (y=0; y<h; ++y)
8134 {
8135 png_const_bytep pRow = store_image_row(ps, pp, 0, y);
8136 png_byte std[STANDARD_ROWMAX];
8137
8138 transform_row(pp, std, in_ct, in_bd, y);
8139
8140 if (processing)
8141 {
8142 unsigned int x;
8143
8144 for (x=0; x<w; ++x)
8145 {
8146 double alpha = 1; /* serves as a flag value */
8147
8148 /* Record the palette index for index images. */
8149 PNG_CONST unsigned int in_index =
8150 in_ct == 3 ? sample(std, 3, in_bd, x, 0) : 256;
8151 PNG_CONST unsigned int out_index =
8152 out_ct == 3 ? sample(std, 3, out_bd, x, 0) : 256;
8153
8154 /* Handle input alpha - png_set_background will cause the output
8155 * alpha to disappear so there is nothing to check.
8156 */
8157 if ((in_ct & PNG_COLOR_MASK_ALPHA) != 0 || (in_ct == 3 &&
8158 in_is_transparent))
8159 {
8160 PNG_CONST unsigned int input_alpha = in_ct == 3 ?
8161 dp->this.palette[in_index].alpha :
8162 sample(std, in_ct, in_bd, x, samples_per_pixel);
8163
8164 unsigned int output_alpha = 65536 /* as a flag value */;
8165
8166 if (out_ct == 3)
8167 {
8168 if (out_is_transparent)
8169 output_alpha = out_palette[out_index].alpha;
8170 }
8171
8172 else if ((out_ct & PNG_COLOR_MASK_ALPHA) != 0)
8173 output_alpha = sample(pRow, out_ct, out_bd, x,
8174 samples_per_pixel);
8175
8176 if (output_alpha != 65536)
8177 alpha = gamma_component_validate("alpha", &vi, input_alpha,
8178 output_alpha, -1/*alpha*/, 0/*background*/);
8179
8180 else /* no alpha in output */
8181 {
8182 /* This is a copy of the calculation of 'i' above in order to
8183 * have the alpha value to use in the background calculation.
8184 */
8185 alpha = input_alpha >> vi.isbit_shift;
8186 alpha /= vi.sbit_max;
8187 }
8188 }
8189
8190 /* Handle grayscale or RGB components. */
8191 if ((in_ct & PNG_COLOR_MASK_COLOR) == 0) /* grayscale */
8192 (void)gamma_component_validate("gray", &vi,
8193 sample(std, in_ct, in_bd, x, 0),
8194 sample(pRow, out_ct, out_bd, x, 0), alpha/*component*/,
8195 vi.background_red);
8196 else /* RGB or palette */
8197 {
8198 (void)gamma_component_validate("red", &vi,
8199 in_ct == 3 ? in_palette[in_index].red :
8200 sample(std, in_ct, in_bd, x, 0),
8201 out_ct == 3 ? out_palette[out_index].red :
8202 sample(pRow, out_ct, out_bd, x, 0),
8203 alpha/*component*/, vi.background_red);
8204
8205 (void)gamma_component_validate("green", &vi,
8206 in_ct == 3 ? in_palette[in_index].green :
8207 sample(std, in_ct, in_bd, x, 1),
8208 out_ct == 3 ? out_palette[out_index].green :
8209 sample(pRow, out_ct, out_bd, x, 1),
8210 alpha/*component*/, vi.background_green);
8211
8212 (void)gamma_component_validate("blue", &vi,
8213 in_ct == 3 ? in_palette[in_index].blue :
8214 sample(std, in_ct, in_bd, x, 2),
8215 out_ct == 3 ? out_palette[out_index].blue :
8216 sample(pRow, out_ct, out_bd, x, 2),
8217 alpha/*component*/, vi.background_blue);
8218 }
8219 }
8220 }
8221
8222 else if (memcmp(std, pRow, cbRow) != 0)
8223 {
8224 char msg[64];
8225
8226 /* No transform is expected on the threshold tests. */
8227 sprintf(msg, "gamma: below threshold row %d changed", y);
8228
8229 png_error(pp, msg);
8230 }
8231 } /* row (y) loop */
8232
8233 dp->this.ps->validated = 1;
8234}
8235
8236static void
8237gamma_end(png_structp pp, png_infop pi)
8238{
8239 gamma_display *dp = voidcast(gamma_display*, png_get_progressive_ptr(pp));
8240
8241 if (!dp->this.speed)
8242 gamma_image_validate(dp, pp, pi);
8243 else
8244 dp->this.ps->validated = 1;
8245}
8246
8247/* A single test run checking a gamma transformation.
8248 *
8249 * maxabs: maximum absolute error as a fraction
8250 * maxout: maximum output error in the output units
8251 * maxpc: maximum percentage error (as a percentage)
8252 */
8253static void
8254gamma_test(png_modifier *pmIn, PNG_CONST png_byte colour_typeIn,
8255 PNG_CONST png_byte bit_depthIn, PNG_CONST int palette_numberIn,
8256 PNG_CONST int interlace_typeIn,
8257 PNG_CONST double file_gammaIn, PNG_CONST double screen_gammaIn,
8258 PNG_CONST png_byte sbitIn, PNG_CONST int threshold_testIn,
8259 PNG_CONST char *name,
8260 PNG_CONST int use_input_precisionIn, PNG_CONST int scale16In,
8261 PNG_CONST int expand16In, PNG_CONST int do_backgroundIn,
8262 PNG_CONST png_color_16 *bkgd_colorIn, double bkgd_gammaIn)
8263{
8264 gamma_display d;
8265 context(&pmIn->this, fault);
8266
8267 gamma_display_init(&d, pmIn, FILEID(colour_typeIn, bit_depthIn,
8268 palette_numberIn, interlace_typeIn, 0, 0, 0),
8269 file_gammaIn, screen_gammaIn, sbitIn,
8270 threshold_testIn, use_input_precisionIn, scale16In,
8271 expand16In, do_backgroundIn, bkgd_colorIn, bkgd_gammaIn);
8272
8273 Try
8274 {
8275 png_structp pp;
8276 png_infop pi;
8277 gama_modification gama_mod;
8278 srgb_modification srgb_mod;
8279 sbit_modification sbit_mod;
8280
8281 /* For the moment don't use the png_modifier support here. */
8282 d.pm->encoding_counter = 0;
8283 modifier_set_encoding(d.pm); /* Just resets everything */
8284 d.pm->current_gamma = d.file_gamma;
8285
8286 /* Make an appropriate modifier to set the PNG file gamma to the
8287 * given gamma value and the sBIT chunk to the given precision.
8288 */
8289 d.pm->modifications = NULL;
8290 gama_modification_init(&gama_mod, d.pm, d.file_gamma);
8291 srgb_modification_init(&srgb_mod, d.pm, 127 /*delete*/);
8292 if (d.sbit > 0)
8293 sbit_modification_init(&sbit_mod, d.pm, d.sbit);
8294
8295 modification_reset(d.pm->modifications);
8296
8297 /* Get a png_struct for writing the image. */
8298 pp = set_modifier_for_read(d.pm, &pi, d.this.id, name);
8299 standard_palette_init(&d.this);
8300
8301 /* Introduce the correct read function. */
8302 if (d.pm->this.progressive)
8303 {
8304 /* Share the row function with the standard implementation. */
8305 png_set_progressive_read_fn(pp, &d, gamma_info, progressive_row,
8306 gamma_end);
8307
8308 /* Now feed data into the reader until we reach the end: */
8309 modifier_progressive_read(d.pm, pp, pi);
8310 }
8311 else
8312 {
8313 /* modifier_read expects a png_modifier* */
8314 png_set_read_fn(pp, d.pm, modifier_read);
8315
8316 /* Check the header values: */
8317 png_read_info(pp, pi);
8318
8319 /* Process the 'info' requirements. Only one image is generated */
8320 gamma_info_imp(&d, pp, pi);
8321
8322 sequential_row(&d.this, pp, pi, -1, 0);
8323
8324 if (!d.this.speed)
8325 gamma_image_validate(&d, pp, pi);
8326 else
8327 d.this.ps->validated = 1;
8328 }
8329
8330 modifier_reset(d.pm);
8331
8332 if (d.pm->log && !d.threshold_test && !d.this.speed)
8333 fprintf(stderr, "%d bit %s %s: max error %f (%.2g, %2g%%)\n",
8334 d.this.bit_depth, colour_types[d.this.colour_type], name,
8335 d.maxerrout, d.maxerrabs, 100*d.maxerrpc);
8336
8337 /* Log the summary values too. */
8338 if (d.this.colour_type == 0 || d.this.colour_type == 4)
8339 {
8340 switch (d.this.bit_depth)
8341 {
8342 case 1:
8343 break;
8344
8345 case 2:
8346 if (d.maxerrout > d.pm->error_gray_2)
8347 d.pm->error_gray_2 = d.maxerrout;
8348
8349 break;
8350
8351 case 4:
8352 if (d.maxerrout > d.pm->error_gray_4)
8353 d.pm->error_gray_4 = d.maxerrout;
8354
8355 break;
8356
8357 case 8:
8358 if (d.maxerrout > d.pm->error_gray_8)
8359 d.pm->error_gray_8 = d.maxerrout;
8360
8361 break;
8362
8363 case 16:
8364 if (d.maxerrout > d.pm->error_gray_16)
8365 d.pm->error_gray_16 = d.maxerrout;
8366
8367 break;
8368
8369 default:
8370 png_error(pp, "bad bit depth (internal: 1)");
8371 }
8372 }
8373
8374 else if (d.this.colour_type == 2 || d.this.colour_type == 6)
8375 {
8376 switch (d.this.bit_depth)
8377 {
8378 case 8:
8379
8380 if (d.maxerrout > d.pm->error_color_8)
8381 d.pm->error_color_8 = d.maxerrout;
8382
8383 break;
8384
8385 case 16:
8386
8387 if (d.maxerrout > d.pm->error_color_16)
8388 d.pm->error_color_16 = d.maxerrout;
8389
8390 break;
8391
8392 default:
8393 png_error(pp, "bad bit depth (internal: 2)");
8394 }
8395 }
8396
8397 else if (d.this.colour_type == 3)
8398 {
8399 if (d.maxerrout > d.pm->error_indexed)
8400 d.pm->error_indexed = d.maxerrout;
8401 }
8402 }
8403
8404 Catch(fault)
8405 modifier_reset((png_modifier*)fault);
8406}
8407
8408static void gamma_threshold_test(png_modifier *pm, png_byte colour_type,
8409 png_byte bit_depth, int interlace_type, double file_gamma,
8410 double screen_gamma)
8411{
8412 size_t pos = 0;
8413 char name[64];
8414 pos = safecat(name, sizeof name, pos, "threshold ");
8415 pos = safecatd(name, sizeof name, pos, file_gamma, 3);
8416 pos = safecat(name, sizeof name, pos, "/");
8417 pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
8418
8419 (void)gamma_test(pm, colour_type, bit_depth, 0/*palette*/, interlace_type,
8420 file_gamma, screen_gamma, 0/*sBIT*/, 1/*threshold test*/, name,
8421 0 /*no input precision*/,
8422 0 /*no scale16*/, 0 /*no expand16*/, 0 /*no background*/, 0 /*hence*/,
8423 0 /*no background gamma*/);
8424}
8425
8426static void
8427perform_gamma_threshold_tests(png_modifier *pm)
8428{
8429 png_byte colour_type = 0;
8430 png_byte bit_depth = 0;
8431 int palette_number = 0;
8432
8433 /* Don't test more than one instance of each palette - it's pointless, in
8434 * fact this test is somewhat excessive since libpng doesn't make this
8435 * decision based on colour type or bit depth!
8436 */
8437 while (next_format(&colour_type, &bit_depth, &palette_number))
8438 if (palette_number == 0)
8439 {
8440 double test_gamma = 1.0;
8441 while (test_gamma >= .4)
8442 {
8443 /* There's little point testing the interlacing vs non-interlacing,
8444 * but this can be set from the command line.
8445 */
8446 gamma_threshold_test(pm, colour_type, bit_depth, pm->interlace_type,
8447 test_gamma, 1/test_gamma);
8448 test_gamma *= .95;
8449 }
8450
8451 /* And a special test for sRGB */
8452 gamma_threshold_test(pm, colour_type, bit_depth, pm->interlace_type,
8453 .45455, 2.2);
8454
8455 if (fail(pm))
8456 return;
8457 }
8458}
8459
8460static void gamma_transform_test(png_modifier *pm,
8461 PNG_CONST png_byte colour_type, PNG_CONST png_byte bit_depth,
8462 PNG_CONST int palette_number,
8463 PNG_CONST int interlace_type, PNG_CONST double file_gamma,
8464 PNG_CONST double screen_gamma, PNG_CONST png_byte sbit,
8465 PNG_CONST int use_input_precision, PNG_CONST int scale16)
8466{
8467 size_t pos = 0;
8468 char name[64];
8469
8470 if (sbit != bit_depth && sbit != 0)
8471 {
8472 pos = safecat(name, sizeof name, pos, "sbit(");
8473 pos = safecatn(name, sizeof name, pos, sbit);
8474 pos = safecat(name, sizeof name, pos, ") ");
8475 }
8476
8477 else
8478 pos = safecat(name, sizeof name, pos, "gamma ");
8479
8480 if (scale16)
8481 pos = safecat(name, sizeof name, pos, "16to8 ");
8482
8483 pos = safecatd(name, sizeof name, pos, file_gamma, 3);
8484 pos = safecat(name, sizeof name, pos, "->");
8485 pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
8486
8487 gamma_test(pm, colour_type, bit_depth, palette_number, interlace_type,
8488 file_gamma, screen_gamma, sbit, 0, name, use_input_precision,
8489 scale16, pm->test_gamma_expand16, 0 , 0, 0);
8490}
8491
8492static void perform_gamma_transform_tests(png_modifier *pm)
8493{
8494 png_byte colour_type = 0;
8495 png_byte bit_depth = 0;
8496 int palette_number = 0;
8497
8498 while (next_format(&colour_type, &bit_depth, &palette_number))
8499 {
8500 unsigned int i, j;
8501
8502 for (i=0; i<pm->ngamma_tests; ++i) for (j=0; j<pm->ngamma_tests; ++j)
8503 if (i != j)
8504 {
8505 gamma_transform_test(pm, colour_type, bit_depth, palette_number,
8506 pm->interlace_type, 1/pm->gammas[i], pm->gammas[j], 0/*sBIT*/,
8507 pm->use_input_precision, 0 /*do not scale16*/);
8508
8509 if (fail(pm))
8510 return;
8511 }
8512 }
8513}
8514
8515static void perform_gamma_sbit_tests(png_modifier *pm)
8516{
8517 png_byte sbit;
8518
8519 /* The only interesting cases are colour and grayscale, alpha is ignored here
8520 * for overall speed. Only bit depths where sbit is less than the bit depth
8521 * are tested.
8522 */
8523 for (sbit=pm->sbitlow; sbit<(1<<READ_BDHI); ++sbit)
8524 {
8525 png_byte colour_type, bit_depth;
8526 int npalette;
8527
8528 colour_type = bit_depth = 0;
8529 npalette = 0;
8530
8531 while (next_format(&colour_type, &bit_depth, &npalette))
8532 if ((colour_type & PNG_COLOR_MASK_ALPHA) == 0 &&
8533 ((colour_type == 3 && sbit < 8) ||
8534 (colour_type != 3 && sbit < bit_depth)))
8535 {
8536 unsigned int i;
8537
8538 for (i=0; i<pm->ngamma_tests; ++i)
8539 {
8540 unsigned int j;
8541
8542 for (j=0; j<pm->ngamma_tests; ++j) if (i != j)
8543 {
8544 gamma_transform_test(pm, colour_type, bit_depth, npalette,
8545 pm->interlace_type, 1/pm->gammas[i], pm->gammas[j],
8546 sbit, pm->use_input_precision_sbit, 0 /*scale16*/);
8547
8548 if (fail(pm))
8549 return;
8550 }
8551 }
8552 }
8553 }
8554}
8555
8556/* Note that this requires a 16 bit source image but produces 8 bit output, so
8557 * we only need the 16bit write support, but the 16 bit images are only
8558 * generated if DO_16BIT is defined.
8559 */
8560#ifdef DO_16BIT
8561static void perform_gamma_scale16_tests(png_modifier *pm)
8562{
8563# ifndef PNG_MAX_GAMMA_8
8564# define PNG_MAX_GAMMA_8 11
8565# endif
8566 /* Include the alpha cases here. Note that sbit matches the internal value
8567 * used by the library - otherwise we will get spurious errors from the
8568 * internal sbit style approximation.
8569 *
8570 * The threshold test is here because otherwise the 16 to 8 conversion will
8571 * proceed *without* gamma correction, and the tests above will fail (but not
8572 * by much) - this could be fixed, it only appears with the -g option.
8573 */
8574 unsigned int i, j;
8575 for (i=0; i<pm->ngamma_tests; ++i)
8576 {
8577 for (j=0; j<pm->ngamma_tests; ++j)
8578 {
8579 if (i != j &&
8580 fabs(pm->gammas[j]/pm->gammas[i]-1) >= PNG_GAMMA_THRESHOLD)
8581 {
8582 gamma_transform_test(pm, 0, 16, 0, pm->interlace_type,
8583 1/pm->gammas[i], pm->gammas[j], PNG_MAX_GAMMA_8,
8584 pm->use_input_precision_16to8, 1 /*scale16*/);
8585
8586 if (fail(pm))
8587 return;
8588
8589 gamma_transform_test(pm, 2, 16, 0, pm->interlace_type,
8590 1/pm->gammas[i], pm->gammas[j], PNG_MAX_GAMMA_8,
8591 pm->use_input_precision_16to8, 1 /*scale16*/);
8592
8593 if (fail(pm))
8594 return;
8595
8596 gamma_transform_test(pm, 4, 16, 0, pm->interlace_type,
8597 1/pm->gammas[i], pm->gammas[j], PNG_MAX_GAMMA_8,
8598 pm->use_input_precision_16to8, 1 /*scale16*/);
8599
8600 if (fail(pm))
8601 return;
8602
8603 gamma_transform_test(pm, 6, 16, 0, pm->interlace_type,
8604 1/pm->gammas[i], pm->gammas[j], PNG_MAX_GAMMA_8,
8605 pm->use_input_precision_16to8, 1 /*scale16*/);
8606
8607 if (fail(pm))
8608 return;
8609 }
8610 }
8611 }
8612}
8613#endif /* 16 to 8 bit conversion */
8614
8615#if defined PNG_READ_BACKGROUND_SUPPORTED ||\
8616 defined PNG_READ_ALPHA_MODE_SUPPORTED
8617static void gamma_composition_test(png_modifier *pm,
8618 PNG_CONST png_byte colour_type, PNG_CONST png_byte bit_depth,
8619 PNG_CONST int palette_number,
8620 PNG_CONST int interlace_type, PNG_CONST double file_gamma,
8621 PNG_CONST double screen_gamma,
8622 PNG_CONST int use_input_precision, PNG_CONST int do_background,
8623 PNG_CONST int expand_16)
8624{
8625 size_t pos = 0;
8626 png_const_charp base;
8627 double bg;
8628 char name[128];
8629 png_color_16 background;
8630
8631 /* Make up a name and get an appropriate background gamma value. */
8632 switch (do_background)
8633 {
8634 default:
8635 base = "";
8636 bg = 4; /* should not be used */
8637 break;
8638 case PNG_BACKGROUND_GAMMA_SCREEN:
8639 base = " bckg(Screen):";
8640 bg = 1/screen_gamma;
8641 break;
8642 case PNG_BACKGROUND_GAMMA_FILE:
8643 base = " bckg(File):";
8644 bg = file_gamma;
8645 break;
8646 case PNG_BACKGROUND_GAMMA_UNIQUE:
8647 base = " bckg(Unique):";
8648 /* This tests the handling of a unique value, the math is such that the
8649 * value tends to be <1, but is neither screen nor file (even if they
8650 * match!)
8651 */
8652 bg = (file_gamma + screen_gamma) / 3;
8653 break;
8654#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
8655 case ALPHA_MODE_OFFSET + PNG_ALPHA_PNG:
8656 base = " alpha(PNG)";
8657 bg = 4; /* should not be used */
8658 break;
8659 case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
8660 base = " alpha(Porter-Duff)";
8661 bg = 4; /* should not be used */
8662 break;
8663 case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
8664 base = " alpha(Optimized)";
8665 bg = 4; /* should not be used */
8666 break;
8667 case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
8668 base = " alpha(Broken)";
8669 bg = 4; /* should not be used */
8670 break;
8671#endif
8672 }
8673
8674 /* Use random background values - the background is always presented in the
8675 * output space (8 or 16 bit components).
8676 */
8677 if (expand_16 || bit_depth == 16)
8678 {
8679 png_uint_32 r = random_32();
8680
8681 background.red = (png_uint_16)r;
8682 background.green = (png_uint_16)(r >> 16);
8683 r = random_32();
8684 background.blue = (png_uint_16)r;
8685 background.gray = (png_uint_16)(r >> 16);
8686 }
8687
8688 else /* 8 bit colors */
8689 {
8690 png_uint_32 r = random_32();
8691
8692 background.red = (png_byte)r;
8693 background.green = (png_byte)(r >> 8);
8694 background.blue = (png_byte)(r >> 16);
8695 background.gray = (png_byte)(r >> 24);
8696 }
8697
8698 background.index = 193; /* rgb(193,193,193) to detect errors */
8699 if (!(colour_type & PNG_COLOR_MASK_COLOR))
8700 {
8701 /* Grayscale input, we do not convert to RGB (TBD), so we must set the
8702 * background to gray - else libpng seems to fail.
8703 */
8704 background.red = background.green = background.blue = background.gray;
8705 }
8706
8707 pos = safecat(name, sizeof name, pos, "gamma ");
8708 pos = safecatd(name, sizeof name, pos, file_gamma, 3);
8709 pos = safecat(name, sizeof name, pos, "->");
8710 pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
8711
8712 pos = safecat(name, sizeof name, pos, base);
8713 if (do_background < ALPHA_MODE_OFFSET)
8714 {
8715 /* Include the background color and gamma in the name: */
8716 pos = safecat(name, sizeof name, pos, "(");
8717 /* This assumes no expand gray->rgb - the current code won't handle that!
8718 */
8719 if (colour_type & PNG_COLOR_MASK_COLOR)
8720 {
8721 pos = safecatn(name, sizeof name, pos, background.red);
8722 pos = safecat(name, sizeof name, pos, ",");
8723 pos = safecatn(name, sizeof name, pos, background.green);
8724 pos = safecat(name, sizeof name, pos, ",");
8725 pos = safecatn(name, sizeof name, pos, background.blue);
8726 }
8727 else
8728 pos = safecatn(name, sizeof name, pos, background.gray);
8729 pos = safecat(name, sizeof name, pos, ")^");
8730 pos = safecatd(name, sizeof name, pos, bg, 3);
8731 }
8732
8733 gamma_test(pm, colour_type, bit_depth, palette_number, interlace_type,
8734 file_gamma, screen_gamma, 0/*sBIT*/, 0, name, use_input_precision,
8735 0/*strip 16*/, expand_16, do_background, &background, bg);
8736}
8737
8738
8739static void
8740perform_gamma_composition_tests(png_modifier *pm, int do_background,
8741 int expand_16)
8742{
8743 png_byte colour_type = 0;
8744 png_byte bit_depth = 0;
8745 int palette_number = 0;
8746
8747 /* Skip the non-alpha cases - there is no setting of a transparency colour at
8748 * present.
8749 */
8750 while (next_format(&colour_type, &bit_depth, &palette_number))
8751 if ((colour_type & PNG_COLOR_MASK_ALPHA) != 0)
8752 {
8753 unsigned int i, j;
8754
8755 /* Don't skip the i==j case here - it's relevant. */
8756 for (i=0; i<pm->ngamma_tests; ++i) for (j=0; j<pm->ngamma_tests; ++j)
8757 {
8758 gamma_composition_test(pm, colour_type, bit_depth, palette_number,
8759 pm->interlace_type, 1/pm->gammas[i], pm->gammas[j],
8760 pm->use_input_precision, do_background, expand_16);
8761
8762 if (fail(pm))
8763 return;
8764 }
8765 }
8766}
8767#endif /* READ_BACKGROUND || READ_ALPHA_MODE */
8768
8769static void
8770init_gamma_errors(png_modifier *pm)
8771{
8772 pm->error_gray_2 = pm->error_gray_4 = pm->error_gray_8 = 0;
8773 pm->error_color_8 = 0;
8774 pm->error_indexed = 0;
8775 pm->error_gray_16 = pm->error_color_16 = 0;
8776}
8777
8778static void
8779summarize_gamma_errors(png_modifier *pm, png_const_charp who, int low_bit_depth)
8780{
8781 if (who)
8782 printf("Gamma correction with %s:\n", who);
8783
8784 if (low_bit_depth)
8785 {
8786 printf(" 2 bit gray: %.5f\n", pm->error_gray_2);
8787 printf(" 4 bit gray: %.5f\n", pm->error_gray_4);
8788 printf(" 8 bit gray: %.5f\n", pm->error_gray_8);
8789 printf(" 8 bit color: %.5f\n", pm->error_color_8);
8790 printf(" indexed: %.5f\n", pm->error_indexed);
8791 }
8792
8793#ifdef DO_16BIT
8794 printf(" 16 bit gray: %.5f\n", pm->error_gray_16);
8795 printf(" 16 bit color: %.5f\n", pm->error_color_16);
8796#endif
8797}
8798
8799static void
8800perform_gamma_test(png_modifier *pm, int summary)
8801{
8802 /*TODO: remove this*/
8803 /* Save certain values for the temporary overrides below. */
8804 unsigned int calculations_use_input_precision =
8805 pm->calculations_use_input_precision;
8806 double maxout8 = pm->maxout8;
8807
8808 /* First some arbitrary no-transform tests: */
8809 if (!pm->this.speed && pm->test_gamma_threshold)
8810 {
8811 perform_gamma_threshold_tests(pm);
8812
8813 if (fail(pm))
8814 return;
8815 }
8816
8817 /* Now some real transforms. */
8818 if (pm->test_gamma_transform)
8819 {
8820 init_gamma_errors(pm);
8821 /*TODO: remove this. Necessary because the current libpng
8822 * implementation works in 8 bits:
8823 */
8824 if (pm->test_gamma_expand16)
8825 pm->calculations_use_input_precision = 1;
8826 perform_gamma_transform_tests(pm);
8827 if (!calculations_use_input_precision)
8828 pm->calculations_use_input_precision = 0;
8829
8830 if (summary)
8831 {
8832 printf("Gamma correction error summary\n\n");
8833 printf("The printed value is the maximum error in the pixel values\n");
8834 printf("calculated by the libpng gamma correction code. The error\n");
8835 printf("is calculated as the difference between the output pixel\n");
8836 printf("value (always an integer) and the ideal value from the\n");
8837 printf("libpng specification (typically not an integer).\n\n");
8838
8839 printf("Expect this value to be less than .5 for 8 bit formats,\n");
8840 printf("less than 1 for formats with fewer than 8 bits and a small\n");
8841 printf("number (typically less than 5) for the 16 bit formats.\n");
8842 printf("For performance reasons the value for 16 bit formats\n");
8843 printf("increases when the image file includes an sBIT chunk.\n\n");
8844
8845 summarize_gamma_errors(pm, 0/*who*/, 1);
8846 }
8847 }
8848
8849 /* The sbit tests produce much larger errors: */
8850 if (pm->test_gamma_sbit)
8851 {
8852 init_gamma_errors(pm);
8853 perform_gamma_sbit_tests(pm);
8854
8855 if (summary)
8856 summarize_gamma_errors(pm, "sBIT", pm->sbitlow < 8U);
8857 }
8858
8859#ifdef DO_16BIT /* Should be READ_16BIT_SUPPORTED */
8860 if (pm->test_gamma_scale16)
8861 {
8862 /* The 16 to 8 bit strip operations: */
8863 init_gamma_errors(pm);
8864 perform_gamma_scale16_tests(pm);
8865
8866 if (summary)
8867 {
8868 printf("Gamma correction with 16 to 8 bit reduction:\n");
8869 printf(" 16 bit gray: %.5f\n", pm->error_gray_16);
8870 printf(" 16 bit color: %.5f\n", pm->error_color_16);
8871 }
8872 }
8873#endif
8874
8875#ifdef PNG_READ_BACKGROUND_SUPPORTED
8876 if (pm->test_gamma_background)
8877 {
8878 init_gamma_errors(pm);
8879
8880 /*TODO: remove this. Necessary because the current libpng
8881 * implementation works in 8 bits:
8882 */
8883 if (pm->test_gamma_expand16)
8884 {
8885 pm->calculations_use_input_precision = 1;
8886 pm->maxout8 = .499; /* because the 16 bit background is smashed */
8887 }
8888 perform_gamma_composition_tests(pm, PNG_BACKGROUND_GAMMA_UNIQUE,
8889 pm->test_gamma_expand16);
8890 if (!calculations_use_input_precision)
8891 pm->calculations_use_input_precision = 0;
8892 pm->maxout8 = maxout8;
8893
8894 if (summary)
8895 summarize_gamma_errors(pm, "background", 1);
8896 }
8897#endif
8898
8899#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
8900 if (pm->test_gamma_alpha_mode)
8901 {
8902 int do_background;
8903
8904 init_gamma_errors(pm);
8905
8906 /*TODO: remove this. Necessary because the current libpng
8907 * implementation works in 8 bits:
8908 */
8909 if (pm->test_gamma_expand16)
8910 pm->calculations_use_input_precision = 1;
8911 for (do_background = ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD;
8912 do_background <= ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN && !fail(pm);
8913 ++do_background)
8914 perform_gamma_composition_tests(pm, do_background,
8915 pm->test_gamma_expand16);
8916 if (!calculations_use_input_precision)
8917 pm->calculations_use_input_precision = 0;
8918
8919 if (summary)
8920 summarize_gamma_errors(pm, "alpha mode", 1);
8921 }
8922#endif
8923}
8924#endif /* PNG_READ_GAMMA_SUPPORTED */
8925
8926/* INTERLACE MACRO VALIDATION */
8927/* This is copied verbatim from the specification, it is simply the pass
8928 * number in which each pixel in each 8x8 tile appears. The array must
8929 * be indexed adam7[y][x] and notice that the pass numbers are based at
8930 * 1, not 0 - the base libpng uses.
8931 */
8932static PNG_CONST
8933png_byte adam7[8][8] =
8934{
8935 { 1,6,4,6,2,6,4,6 },
8936 { 7,7,7,7,7,7,7,7 },
8937 { 5,6,5,6,5,6,5,6 },
8938 { 7,7,7,7,7,7,7,7 },
8939 { 3,6,4,6,3,6,4,6 },
8940 { 7,7,7,7,7,7,7,7 },
8941 { 5,6,5,6,5,6,5,6 },
8942 { 7,7,7,7,7,7,7,7 }
8943};
8944
8945/* This routine validates all the interlace support macros in png.h for
8946 * a variety of valid PNG widths and heights. It uses a number of similarly
8947 * named internal routines that feed off the above array.
8948 */
8949static png_uint_32
8950png_pass_start_row(int pass)
8951{
8952 int x, y;
8953 ++pass;
8954 for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
8955 return y;
8956 return 0xf;
8957}
8958
8959static png_uint_32
8960png_pass_start_col(int pass)
8961{
8962 int x, y;
8963 ++pass;
8964 for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
8965 return x;
8966 return 0xf;
8967}
8968
8969static int
8970png_pass_row_shift(int pass)
8971{
8972 int x, y, base=(-1), inc=8;
8973 ++pass;
8974 for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
8975 {
8976 if (base == (-1))
8977 base = y;
8978 else if (base == y)
8979 {}
8980 else if (inc == y-base)
8981 base=y;
8982 else if (inc == 8)
8983 inc = y-base, base=y;
8984 else if (inc != y-base)
8985 return 0xff; /* error - more than one 'inc' value! */
8986 }
8987
8988 if (base == (-1)) return 0xfe; /* error - no row in pass! */
8989
8990 /* The shift is always 1, 2 or 3 - no pass has all the rows! */
8991 switch (inc)
8992 {
8993case 2: return 1;
8994case 4: return 2;
8995case 8: return 3;
8996default: break;
8997 }
8998
8999 /* error - unrecognized 'inc' */
9000 return (inc << 8) + 0xfd;
9001}
9002
9003static int
9004png_pass_col_shift(int pass)
9005{
9006 int x, y, base=(-1), inc=8;
9007 ++pass;
9008 for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
9009 {
9010 if (base == (-1))
9011 base = x;
9012 else if (base == x)
9013 {}
9014 else if (inc == x-base)
9015 base=x;
9016 else if (inc == 8)
9017 inc = x-base, base=x;
9018 else if (inc != x-base)
9019 return 0xff; /* error - more than one 'inc' value! */
9020 }
9021
9022 if (base == (-1)) return 0xfe; /* error - no row in pass! */
9023
9024 /* The shift is always 1, 2 or 3 - no pass has all the rows! */
9025 switch (inc)
9026 {
9027case 1: return 0; /* pass 7 has all the columns */
9028case 2: return 1;
9029case 4: return 2;
9030case 8: return 3;
9031default: break;
9032 }
9033
9034 /* error - unrecognized 'inc' */
9035 return (inc << 8) + 0xfd;
9036}
9037
9038static png_uint_32
9039png_row_from_pass_row(png_uint_32 yIn, int pass)
9040{
9041 /* By examination of the array: */
9042 switch (pass)
9043 {
9044case 0: return yIn * 8;
9045case 1: return yIn * 8;
9046case 2: return yIn * 8 + 4;
9047case 3: return yIn * 4;
9048case 4: return yIn * 4 + 2;
9049case 5: return yIn * 2;
9050case 6: return yIn * 2 + 1;
9051default: break;
9052 }
9053
9054 return 0xff; /* bad pass number */
9055}
9056
9057static png_uint_32
9058png_col_from_pass_col(png_uint_32 xIn, int pass)
9059{
9060 /* By examination of the array: */
9061 switch (pass)
9062 {
9063case 0: return xIn * 8;
9064case 1: return xIn * 8 + 4;
9065case 2: return xIn * 4;
9066case 3: return xIn * 4 + 2;
9067case 4: return xIn * 2;
9068case 5: return xIn * 2 + 1;
9069case 6: return xIn;
9070default: break;
9071 }
9072
9073 return 0xff; /* bad pass number */
9074}
9075
9076static int
9077png_row_in_interlace_pass(png_uint_32 y, int pass)
9078{
9079 /* Is row 'y' in pass 'pass'? */
9080 int x;
9081 y &= 7;
9082 ++pass;
9083 for (x=0; x<8; ++x) if (adam7[y][x] == pass)
9084 return 1;
9085
9086 return 0;
9087}
9088
9089static int
9090png_col_in_interlace_pass(png_uint_32 x, int pass)
9091{
9092 /* Is column 'x' in pass 'pass'? */
9093 int y;
9094 x &= 7;
9095 ++pass;
9096 for (y=0; y<8; ++y) if (adam7[y][x] == pass)
9097 return 1;
9098
9099 return 0;
9100}
9101
9102static png_uint_32
9103png_pass_rows(png_uint_32 height, int pass)
9104{
9105 png_uint_32 tiles = height>>3;
9106 png_uint_32 rows = 0;
9107 unsigned int x, y;
9108
9109 height &= 7;
9110 ++pass;
9111 for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
9112 {
9113 rows += tiles;
9114 if (y < height) ++rows;
9115 break; /* i.e. break the 'x', column, loop. */
9116 }
9117
9118 return rows;
9119}
9120
9121static png_uint_32
9122png_pass_cols(png_uint_32 width, int pass)
9123{
9124 png_uint_32 tiles = width>>3;
9125 png_uint_32 cols = 0;
9126 unsigned int x, y;
9127
9128 width &= 7;
9129 ++pass;
9130 for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
9131 {
9132 cols += tiles;
9133 if (x < width) ++cols;
9134 break; /* i.e. break the 'y', row, loop. */
9135 }
9136
9137 return cols;
9138}
9139
9140static void
9141perform_interlace_macro_validation(void)
9142{
9143 /* The macros to validate, first those that depend only on pass:
9144 *
9145 * PNG_PASS_START_ROW(pass)
9146 * PNG_PASS_START_COL(pass)
9147 * PNG_PASS_ROW_SHIFT(pass)
9148 * PNG_PASS_COL_SHIFT(pass)
9149 */
9150 int pass;
9151
9152 for (pass=0; pass<7; ++pass)
9153 {
9154 png_uint_32 m, f, v;
9155
9156 m = PNG_PASS_START_ROW(pass);
9157 f = png_pass_start_row(pass);
9158 if (m != f)
9159 {
9160 fprintf(stderr, "PNG_PASS_START_ROW(%d) = %u != %x\n", pass, m, f);
9161 exit(1);
9162 }
9163
9164 m = PNG_PASS_START_COL(pass);
9165 f = png_pass_start_col(pass);
9166 if (m != f)
9167 {
9168 fprintf(stderr, "PNG_PASS_START_COL(%d) = %u != %x\n", pass, m, f);
9169 exit(1);
9170 }
9171
9172 m = PNG_PASS_ROW_SHIFT(pass);
9173 f = png_pass_row_shift(pass);
9174 if (m != f)
9175 {
9176 fprintf(stderr, "PNG_PASS_ROW_SHIFT(%d) = %u != %x\n", pass, m, f);
9177 exit(1);
9178 }
9179
9180 m = PNG_PASS_COL_SHIFT(pass);
9181 f = png_pass_col_shift(pass);
9182 if (m != f)
9183 {
9184 fprintf(stderr, "PNG_PASS_COL_SHIFT(%d) = %u != %x\n", pass, m, f);
9185 exit(1);
9186 }
9187
9188 /* Macros that depend on the image or sub-image height too:
9189 *
9190 * PNG_PASS_ROWS(height, pass)
9191 * PNG_PASS_COLS(width, pass)
9192 * PNG_ROW_FROM_PASS_ROW(yIn, pass)
9193 * PNG_COL_FROM_PASS_COL(xIn, pass)
9194 * PNG_ROW_IN_INTERLACE_PASS(y, pass)
9195 * PNG_COL_IN_INTERLACE_PASS(x, pass)
9196 */
9197 for (v=0;;)
9198 {
9199 /* First the base 0 stuff: */
9200 m = PNG_ROW_FROM_PASS_ROW(v, pass);
9201 f = png_row_from_pass_row(v, pass);
9202 if (m != f)
9203 {
9204 fprintf(stderr, "PNG_ROW_FROM_PASS_ROW(%u, %d) = %u != %x\n",
9205 v, pass, m, f);
9206 exit(1);
9207 }
9208
9209 m = PNG_COL_FROM_PASS_COL(v, pass);
9210 f = png_col_from_pass_col(v, pass);
9211 if (m != f)
9212 {
9213 fprintf(stderr, "PNG_COL_FROM_PASS_COL(%u, %d) = %u != %x\n",
9214 v, pass, m, f);
9215 exit(1);
9216 }
9217
9218 m = PNG_ROW_IN_INTERLACE_PASS(v, pass);
9219 f = png_row_in_interlace_pass(v, pass);
9220 if (m != f)
9221 {
9222 fprintf(stderr, "PNG_ROW_IN_INTERLACE_PASS(%u, %d) = %u != %x\n",
9223 v, pass, m, f);
9224 exit(1);
9225 }
9226
9227 m = PNG_COL_IN_INTERLACE_PASS(v, pass);
9228 f = png_col_in_interlace_pass(v, pass);
9229 if (m != f)
9230 {
9231 fprintf(stderr, "PNG_COL_IN_INTERLACE_PASS(%u, %d) = %u != %x\n",
9232 v, pass, m, f);
9233 exit(1);
9234 }
9235
9236 /* Then the base 1 stuff: */
9237 ++v;
9238 m = PNG_PASS_ROWS(v, pass);
9239 f = png_pass_rows(v, pass);
9240 if (m != f)
9241 {
9242 fprintf(stderr, "PNG_PASS_ROWS(%u, %d) = %u != %x\n",
9243 v, pass, m, f);
9244 exit(1);
9245 }
9246
9247 m = PNG_PASS_COLS(v, pass);
9248 f = png_pass_cols(v, pass);
9249 if (m != f)
9250 {
9251 fprintf(stderr, "PNG_PASS_COLS(%u, %d) = %u != %x\n",
9252 v, pass, m, f);
9253 exit(1);
9254 }
9255
9256 /* Move to the next v - the stepping algorithm starts skipping
9257 * values above 1024.
9258 */
9259 if (v > 1024)
9260 {
9261 if (v == PNG_UINT_31_MAX)
9262 break;
9263
9264 v = (v << 1) ^ v;
9265 if (v >= PNG_UINT_31_MAX)
9266 v = PNG_UINT_31_MAX-1;
9267 }
9268 }
9269 }
9270}
9271
9272/* Test color encodings. These values are back-calculated from the published
9273 * chromaticities. The values are accurate to about 14 decimal places; 15 are
9274 * given. These values are much more accurate than the ones given in the spec,
9275 * which typically don't exceed 4 decimal places. This allows testing of the
9276 * libpng code to its theoretical accuracy of 4 decimal places. (If pngvalid
9277 * used the published errors the 'slack' permitted would have to be +/-.5E-4 or
9278 * more.)
9279 *
9280 * The png_modifier code assumes that encodings[0] is sRGB and treats it
9281 * specially: do not change the first entry in this list!
9282 */
9283static PNG_CONST color_encoding test_encodings[] =
9284{
9285/* sRGB: must be first in this list! */
9286/*gamma:*/ { 1/2.2,
9287/*red: */ { 0.412390799265959, 0.212639005871510, 0.019330818715592 },
9288/*green:*/ { 0.357584339383878, 0.715168678767756, 0.119194779794626 },
9289/*blue: */ { 0.180480788401834, 0.072192315360734, 0.950532152249660} },
9290/* Kodak ProPhoto (wide gamut) */
9291/*gamma:*/ { 1/1.6 /*approximate: uses 1.8 power law compared to sRGB 2.4*/,
9292/*red: */ { 0.797760489672303, 0.288071128229293, 0.000000000000000 },
9293/*green:*/ { 0.135185837175740, 0.711843217810102, 0.000000000000000 },
9294/*blue: */ { 0.031349349581525, 0.000085653960605, 0.825104602510460} },
9295/* Adobe RGB (1998) */
9296/*gamma:*/ { 1/(2+51./256),
9297/*red: */ { 0.576669042910131, 0.297344975250536, 0.027031361386412 },
9298/*green:*/ { 0.185558237906546, 0.627363566255466, 0.070688852535827 },
9299/*blue: */ { 0.188228646234995, 0.075291458493998, 0.991337536837639} },
9300/* Adobe Wide Gamut RGB */
9301/*gamma:*/ { 1/(2+51./256),
9302/*red: */ { 0.716500716779386, 0.258728243040113, 0.000000000000000 },
9303/*green:*/ { 0.101020574397477, 0.724682314948566, 0.051211818965388 },
9304/*blue: */ { 0.146774385252705, 0.016589442011321, 0.773892783545073} },
9305};
9306
9307/* signal handler
9308 *
9309 * This attempts to trap signals and escape without crashing. It needs a
9310 * context pointer so that it can throw an exception (call longjmp) to recover
9311 * from the condition; this is handled by making the png_modifier used by 'main'
9312 * into a global variable.
9313 */
9314static png_modifier pm;
9315
9316static void signal_handler(int signum)
9317{
9318
9319 size_t pos = 0;
9320 char msg[64];
9321
9322 pos = safecat(msg, sizeof msg, pos, "caught signal: ");
9323
9324 switch (signum)
9325 {
9326 case SIGABRT:
9327 pos = safecat(msg, sizeof msg, pos, "abort");
9328 break;
9329
9330 case SIGFPE:
9331 pos = safecat(msg, sizeof msg, pos, "floating point exception");
9332 break;
9333
9334 case SIGILL:
9335 pos = safecat(msg, sizeof msg, pos, "illegal instruction");
9336 break;
9337
9338 case SIGINT:
9339 pos = safecat(msg, sizeof msg, pos, "interrupt");
9340 break;
9341
9342 case SIGSEGV:
9343 pos = safecat(msg, sizeof msg, pos, "invalid memory access");
9344 break;
9345
9346 case SIGTERM:
9347 pos = safecat(msg, sizeof msg, pos, "termination request");
9348 break;
9349
9350 default:
9351 pos = safecat(msg, sizeof msg, pos, "unknown ");
9352 pos = safecatn(msg, sizeof msg, pos, signum);
9353 break;
9354 }
9355
9356 store_log(&pm.this, NULL/*png_structp*/, msg, 1/*error*/);
9357
9358 /* And finally throw an exception so we can keep going, unless this is
9359 * SIGTERM in which case stop now.
9360 */
9361 if (signum != SIGTERM)
9362 {
9363 struct exception_context *the_exception_context =
9364 &pm.this.exception_context;
9365
9366 Throw &pm.this;
9367 }
9368
9369 else
9370 exit(1);
9371}
9372
9373/* main program */
9374int main(int argc, PNG_CONST char **argv)
9375{
9376 volatile int summary = 1; /* Print the error summary at the end */
9377 volatile int memstats = 0; /* Print memory statistics at the end */
9378
9379 /* Create the given output file on success: */
9380 PNG_CONST char *volatile touch = NULL;
9381
9382 /* This is an array of standard gamma values (believe it or not I've seen
9383 * every one of these mentioned somewhere.)
9384 *
9385 * In the following list the most useful values are first!
9386 */
9387 static double
9388 gammas[]={2.2, 1.0, 2.2/1.45, 1.8, 1.5, 2.4, 2.5, 2.62, 2.9};
9389
9390 /* This records the command and arguments: */
9391 size_t cp = 0;
9392 char command[1024];
9393
9394 anon_context(&pm.this);
9395
9396 /* Add appropriate signal handlers, just the ANSI specified ones: */
9397 signal(SIGABRT, signal_handler);
9398 signal(SIGFPE, signal_handler);
9399 signal(SIGILL, signal_handler);
9400 signal(SIGINT, signal_handler);
9401 signal(SIGSEGV, signal_handler);
9402 signal(SIGTERM, signal_handler);
9403
9404#ifdef HAVE_FEENABLEEXCEPT
9405 /* Only required to enable FP exceptions on platforms where they start off
9406 * disabled; this is not necessary but if it is not done pngvalid will likely
9407 * end up ignoring FP conditions that other platforms fault.
9408 */
9409 feenableexcept(FE_DIVBYZERO | FE_INVALID | FE_OVERFLOW);
9410#endif
9411
9412 modifier_init(&pm);
9413
9414 /* Preallocate the image buffer, because we know how big it needs to be,
9415 * note that, for testing purposes, it is deliberately mis-aligned by tag
9416 * bytes either side. All rows have an additional five bytes of padding for
9417 * overwrite checking.
9418 */
9419 store_ensure_image(&pm.this, NULL, 2, TRANSFORM_ROWMAX, TRANSFORM_HEIGHTMAX);
9420
9421 /* Don't give argv[0], it's normally some horrible libtool string: */
9422 cp = safecat(command, sizeof command, cp, "pngvalid");
9423
9424 /* Default to error on warning: */
9425 pm.this.treat_warnings_as_errors = 1;
9426
9427 /* Store the test gammas */
9428 pm.gammas = gammas;
9429 pm.ngammas = (sizeof gammas) / (sizeof gammas[0]);
9430 pm.ngamma_tests = 0; /* default to off */
9431
9432 /* And the test encodings */
9433 pm.encodings = test_encodings;
9434 pm.nencodings = (sizeof test_encodings) / (sizeof test_encodings[0]);
9435
9436 pm.sbitlow = 8U; /* because libpng doesn't do sBIT below 8! */
9437 /* The following allows results to pass if they correspond to anything in the
9438 * transformed range [input-.5,input+.5]; this is is required because of the
9439 * way libpng treates the 16_TO_8 flag when building the gamma tables.
9440 *
9441 * TODO: review this
9442 */
9443 pm.use_input_precision_16to8 = 1U;
9444
9445 /* Some default values (set the behavior for 'make check' here).
9446 * These values simply control the maximum error permitted in the gamma
9447 * transformations. The practial limits for human perception are described
9448 * below (the setting for maxpc16), however for 8 bit encodings it isn't
9449 * possible to meet the accepted capabilities of human vision - i.e. 8 bit
9450 * images can never be good enough, regardless of encoding.
9451 */
9452 pm.maxout8 = .1; /* Arithmetic error in *encoded* value */
9453 pm.maxabs8 = .00005; /* 1/20000 */
9454 pm.maxcalc8 = .004; /* +/-1 in 8 bits for compose errors */
9455 pm.maxpc8 = .499; /* I.e., .499% fractional error */
9456 pm.maxout16 = .499; /* Error in *encoded* value */
9457 pm.maxabs16 = .00005;/* 1/20000 */
9458 pm.maxcalc16 =.000015;/* +/-1 in 16 bits for compose errors */
9459
9460 /* NOTE: this is a reasonable perceptual limit. We assume that humans can
9461 * perceive light level differences of 1% over a 100:1 range, so we need to
9462 * maintain 1 in 10000 accuracy (in linear light space), which is what the
9463 * following guarantees. It also allows significantly higher errors at
9464 * higher 16 bit values, which is important for performance. The actual
9465 * maximum 16 bit error is about +/-1.9 in the fixed point implementation but
9466 * this is only allowed for values >38149 by the following:
9467 */
9468 pm.maxpc16 = .005; /* I.e., 1/200% - 1/20000 */
9469
9470 /* Now parse the command line options. */
9471 while (--argc >= 1)
9472 {
9473 int catmore = 0; /* Set if the argument has an argument. */
9474
9475 /* Record each argument for posterity: */
9476 cp = safecat(command, sizeof command, cp, " ");
9477 cp = safecat(command, sizeof command, cp, *++argv);
9478
9479 if (strcmp(*argv, "-v") == 0)
9480 pm.this.verbose = 1;
9481
9482 else if (strcmp(*argv, "-l") == 0)
9483 pm.log = 1;
9484
9485 else if (strcmp(*argv, "-q") == 0)
9486 summary = pm.this.verbose = pm.log = 0;
9487
9488 else if (strcmp(*argv, "-w") == 0)
9489 pm.this.treat_warnings_as_errors = 0;
9490
9491 else if (strcmp(*argv, "--speed") == 0)
9492 pm.this.speed = 1, pm.ngamma_tests = pm.ngammas, pm.test_standard = 0,
9493 summary = 0;
9494
9495 else if (strcmp(*argv, "--memory") == 0)
9496 memstats = 1;
9497
9498 else if (strcmp(*argv, "--size") == 0)
9499 pm.test_size = 1;
9500
9501 else if (strcmp(*argv, "--nosize") == 0)
9502 pm.test_size = 0;
9503
9504 else if (strcmp(*argv, "--standard") == 0)
9505 pm.test_standard = 1;
9506
9507 else if (strcmp(*argv, "--nostandard") == 0)
9508 pm.test_standard = 0;
9509
9510 else if (strcmp(*argv, "--transform") == 0)
9511 pm.test_transform = 1;
9512
9513 else if (strcmp(*argv, "--notransform") == 0)
9514 pm.test_transform = 0;
9515
9516#ifdef PNG_READ_TRANSFORMS_SUPPORTED
9517 else if (strncmp(*argv, "--transform-disable=",
9518 sizeof "--transform-disable") == 0)
9519 {
9520 pm.test_transform = 1;
9521 transform_disable(*argv + sizeof "--transform-disable");
9522 }
9523
9524 else if (strncmp(*argv, "--transform-enable=",
9525 sizeof "--transform-enable") == 0)
9526 {
9527 pm.test_transform = 1;
9528 transform_enable(*argv + sizeof "--transform-enable");
9529 }
9530#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
9531
9532 else if (strcmp(*argv, "--gamma") == 0)
9533 {
9534 /* Just do two gamma tests here (2.2 and linear) for speed: */
9535 pm.ngamma_tests = 2U;
9536 pm.test_gamma_threshold = 1;
9537 pm.test_gamma_transform = 1;
9538 pm.test_gamma_sbit = 1;
9539 pm.test_gamma_scale16 = 1;
9540 pm.test_gamma_background = 1;
9541 pm.test_gamma_alpha_mode = 1;
9542 }
9543
9544 else if (strcmp(*argv, "--nogamma") == 0)
9545 pm.ngamma_tests = 0;
9546
9547 else if (strcmp(*argv, "--gamma-threshold") == 0)
9548 pm.ngamma_tests = 2U, pm.test_gamma_threshold = 1;
9549
9550 else if (strcmp(*argv, "--nogamma-threshold") == 0)
9551 pm.test_gamma_threshold = 0;
9552
9553 else if (strcmp(*argv, "--gamma-transform") == 0)
9554 pm.ngamma_tests = 2U, pm.test_gamma_transform = 1;
9555
9556 else if (strcmp(*argv, "--nogamma-transform") == 0)
9557 pm.test_gamma_transform = 0;
9558
9559 else if (strcmp(*argv, "--gamma-sbit") == 0)
9560 pm.ngamma_tests = 2U, pm.test_gamma_sbit = 1;
9561
9562 else if (strcmp(*argv, "--nogamma-sbit") == 0)
9563 pm.test_gamma_sbit = 0;
9564
9565 else if (strcmp(*argv, "--gamma-16-to-8") == 0)
9566 pm.ngamma_tests = 2U, pm.test_gamma_scale16 = 1;
9567
9568 else if (strcmp(*argv, "--nogamma-16-to-8") == 0)
9569 pm.test_gamma_scale16 = 0;
9570
9571 else if (strcmp(*argv, "--gamma-background") == 0)
9572 pm.ngamma_tests = 2U, pm.test_gamma_background = 1;
9573
9574 else if (strcmp(*argv, "--nogamma-background") == 0)
9575 pm.test_gamma_background = 0;
9576
9577 else if (strcmp(*argv, "--gamma-alpha-mode") == 0)
9578 pm.ngamma_tests = 2U, pm.test_gamma_alpha_mode = 1;
9579
9580 else if (strcmp(*argv, "--nogamma-alpha-mode") == 0)
9581 pm.test_gamma_alpha_mode = 0;
9582
9583 else if (strcmp(*argv, "--expand16") == 0)
9584 pm.test_gamma_expand16 = 1;
9585
9586 else if (strcmp(*argv, "--noexpand16") == 0)
9587 pm.test_gamma_expand16 = 0;
9588
9589 else if (strcmp(*argv, "--more-gammas") == 0)
9590 pm.ngamma_tests = 3U;
9591
9592 else if (strcmp(*argv, "--all-gammas") == 0)
9593 pm.ngamma_tests = pm.ngammas;
9594
9595 else if (strcmp(*argv, "--progressive-read") == 0)
9596 pm.this.progressive = 1;
9597
9598 else if (strcmp(*argv, "--use-update-info") == 0)
9599 ++pm.use_update_info; /* Can call multiple times */
9600
9601 else if (strcmp(*argv, "--interlace") == 0)
9602 pm.interlace_type = PNG_INTERLACE_ADAM7;
9603
9604 else if (strcmp(*argv, "--use-input-precision") == 0)
9605 pm.use_input_precision = 1;
9606
9607 else if (strcmp(*argv, "--calculations-use-input-precision") == 0)
9608 pm.calculations_use_input_precision = 1;
9609
9610 else if (strcmp(*argv, "--assume-16-bit-calculations") == 0)
9611 pm.assume_16_bit_calculations = 1;
9612
9613 else if (strcmp(*argv, "--calculations-follow-bit-depth") == 0)
9614 pm.calculations_use_input_precision =
9615 pm.assume_16_bit_calculations = 0;
9616
9617 else if (strcmp(*argv, "--exhaustive") == 0)
9618 pm.test_exhaustive = 1;
9619
9620 else if (argc > 1 && strcmp(*argv, "--sbitlow") == 0)
9621 --argc, pm.sbitlow = (png_byte)atoi(*++argv), catmore = 1;
9622
9623 else if (argc > 1 && strcmp(*argv, "--touch") == 0)
9624 --argc, touch = *++argv, catmore = 1;
9625
9626 else if (argc > 1 && strncmp(*argv, "--max", 5) == 0)
9627 {
9628 --argc;
9629
9630 if (strcmp(5+*argv, "abs8") == 0)
9631 pm.maxabs8 = atof(*++argv);
9632
9633 else if (strcmp(5+*argv, "abs16") == 0)
9634 pm.maxabs16 = atof(*++argv);
9635
9636 else if (strcmp(5+*argv, "calc8") == 0)
9637 pm.maxcalc8 = atof(*++argv);
9638
9639 else if (strcmp(5+*argv, "calc16") == 0)
9640 pm.maxcalc16 = atof(*++argv);
9641
9642 else if (strcmp(5+*argv, "out8") == 0)
9643 pm.maxout8 = atof(*++argv);
9644
9645 else if (strcmp(5+*argv, "out16") == 0)
9646 pm.maxout16 = atof(*++argv);
9647
9648 else if (strcmp(5+*argv, "pc8") == 0)
9649 pm.maxpc8 = atof(*++argv);
9650
9651 else if (strcmp(5+*argv, "pc16") == 0)
9652 pm.maxpc16 = atof(*++argv);
9653
9654 else
9655 {
9656 fprintf(stderr, "pngvalid: %s: unknown 'max' option\n", *argv);
9657 exit(1);
9658 }
9659
9660 catmore = 1;
9661 }
9662
9663 else if (strcmp(*argv, "--log8") == 0)
9664 --argc, pm.log8 = atof(*++argv), catmore = 1;
9665
9666 else if (strcmp(*argv, "--log16") == 0)
9667 --argc, pm.log16 = atof(*++argv), catmore = 1;
9668
9669 else
9670 {
9671 fprintf(stderr, "pngvalid: %s: unknown argument\n", *argv);
9672 exit(1);
9673 }
9674
9675 if (catmore) /* consumed an extra *argv */
9676 {
9677 cp = safecat(command, sizeof command, cp, " ");
9678 cp = safecat(command, sizeof command, cp, *argv);
9679 }
9680 }
9681
9682 /* If pngvalid is run with no arguments default to a reasonable set of the
9683 * tests.
9684 */
9685 if (pm.test_standard == 0 && pm.test_size == 0 && pm.test_transform == 0 &&
9686 pm.ngamma_tests == 0)
9687 {
9688 /* Make this do all the tests done in the test shell scripts with the same
9689 * parameters, where possible. The limitation is that all the progressive
9690 * read and interlace stuff has to be done in separate runs, so only the
9691 * basic 'standard' and 'size' tests are done.
9692 */
9693 pm.test_standard = 1;
9694 pm.test_size = 1;
9695 pm.test_transform = 1;
9696 pm.ngamma_tests = 2U;
9697 }
9698
9699 if (pm.ngamma_tests > 0 &&
9700 pm.test_gamma_threshold == 0 && pm.test_gamma_transform == 0 &&
9701 pm.test_gamma_sbit == 0 && pm.test_gamma_scale16 == 0 &&
9702 pm.test_gamma_background == 0 && pm.test_gamma_alpha_mode == 0)
9703 {
9704 pm.test_gamma_threshold = 1;
9705 pm.test_gamma_transform = 1;
9706 pm.test_gamma_sbit = 1;
9707 pm.test_gamma_scale16 = 1;
9708 pm.test_gamma_background = 1;
9709 pm.test_gamma_alpha_mode = 1;
9710 }
9711
9712 else if (pm.ngamma_tests == 0)
9713 {
9714 /* Nothing to test so turn everything off: */
9715 pm.test_gamma_threshold = 0;
9716 pm.test_gamma_transform = 0;
9717 pm.test_gamma_sbit = 0;
9718 pm.test_gamma_scale16 = 0;
9719 pm.test_gamma_background = 0;
9720 pm.test_gamma_alpha_mode = 0;
9721 }
9722
9723 Try
9724 {
9725 /* Make useful base images */
9726 make_transform_images(&pm.this);
9727
9728 /* Perform the standard and gamma tests. */
9729 if (pm.test_standard)
9730 {
9731 perform_interlace_macro_validation();
9732 perform_formatting_test(&pm.this);
9733 perform_standard_test(&pm);
9734 perform_error_test(&pm);
9735 }
9736
9737 /* Various oddly sized images: */
9738 if (pm.test_size)
9739 {
9740 make_size_images(&pm.this);
9741 perform_size_test(&pm);
9742 }
9743
9744#ifdef PNG_READ_TRANSFORMS_SUPPORTED
9745 /* Combinatorial transforms: */
9746 if (pm.test_transform)
9747 perform_transform_test(&pm);
9748#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
9749
9750#ifdef PNG_READ_GAMMA_SUPPORTED
9751 if (pm.ngamma_tests > 0)
9752 perform_gamma_test(&pm, summary);
9753#endif
9754 }
9755
9756 Catch_anonymous
9757 {
9758 fprintf(stderr, "pngvalid: test aborted (probably failed in cleanup)\n");
9759 if (!pm.this.verbose)
9760 {
9761 if (pm.this.error[0] != 0)
9762 fprintf(stderr, "pngvalid: first error: %s\n", pm.this.error);
9763
9764 fprintf(stderr, "pngvalid: run with -v to see what happened\n");
9765 }
9766 exit(1);
9767 }
9768
9769 if (summary)
9770 {
9771 printf("%s: %s (%s point arithmetic)\n",
9772 (pm.this.nerrors || (pm.this.treat_warnings_as_errors &&
9773 pm.this.nwarnings)) ? "FAIL" : "PASS",
9774 command,
9775#if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || PNG_LIBPNG_VER < 10500
9776 "floating"
9777#else
9778 "fixed"
9779#endif
9780 );
9781 }
9782
9783 if (memstats)
9784 {
9785 printf("Allocated memory statistics (in bytes):\n"
9786 "\tread %lu maximum single, %lu peak, %lu total\n"
9787 "\twrite %lu maximum single, %lu peak, %lu total\n",
9788 (unsigned long)pm.this.read_memory_pool.max_max,
9789 (unsigned long)pm.this.read_memory_pool.max_limit,
9790 (unsigned long)pm.this.read_memory_pool.max_total,
9791 (unsigned long)pm.this.write_memory_pool.max_max,
9792 (unsigned long)pm.this.write_memory_pool.max_limit,
9793 (unsigned long)pm.this.write_memory_pool.max_total);
9794 }
9795
9796 /* Do this here to provoke memory corruption errors in memory not directly
9797 * allocated by libpng - not a complete test, but better than nothing.
9798 */
9799 store_delete(&pm.this);
9800
9801 /* Error exit if there are any errors, and maybe if there are any
9802 * warnings.
9803 */
9804 if (pm.this.nerrors || (pm.this.treat_warnings_as_errors &&
9805 pm.this.nwarnings))
9806 {
9807 if (!pm.this.verbose)
9808 fprintf(stderr, "pngvalid: %s\n", pm.this.error);
9809
9810 fprintf(stderr, "pngvalid: %d errors, %d warnings\n", pm.this.nerrors,
9811 pm.this.nwarnings);
9812
9813 exit(1);
9814 }
9815
9816 /* Success case. */
9817 if (touch != NULL)
9818 {
9819 FILE *fsuccess = fopen(touch, "wt");
9820
9821 if (fsuccess != NULL)
9822 {
9823 int error = 0;
9824 fprintf(fsuccess, "PNG validation succeeded\n");
9825 fflush(fsuccess);
9826 error = ferror(fsuccess);
9827
9828 if (fclose(fsuccess) || error)
9829 {
9830 fprintf(stderr, "%s: write failed\n", touch);
9831 exit(1);
9832 }
9833 }
9834 }
9835
9836 return 0;
9837}
generated by cgit v1.1 at 2024-07-12 04:58:57 +0000