diff options
Diffstat (limited to 'libraries/irrlicht-1.8/source/Irrlicht/jpeglib/jdhuff.c')
-rw-r--r-- | libraries/irrlicht-1.8/source/Irrlicht/jpeglib/jdhuff.c | 1541 |
1 files changed, 1541 insertions, 0 deletions
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/jpeglib/jdhuff.c b/libraries/irrlicht-1.8/source/Irrlicht/jpeglib/jdhuff.c new file mode 100644 index 0000000..9694117 --- /dev/null +++ b/libraries/irrlicht-1.8/source/Irrlicht/jpeglib/jdhuff.c | |||
@@ -0,0 +1,1541 @@ | |||
1 | /* | ||
2 | * jdhuff.c | ||
3 | * | ||
4 | * Copyright (C) 1991-1997, Thomas G. Lane. | ||
5 | * Modified 2006-2009 by Guido Vollbeding. | ||
6 | * This file is part of the Independent JPEG Group's software. | ||
7 | * For conditions of distribution and use, see the accompanying README file. | ||
8 | * | ||
9 | * This file contains Huffman entropy decoding routines. | ||
10 | * Both sequential and progressive modes are supported in this single module. | ||
11 | * | ||
12 | * Much of the complexity here has to do with supporting input suspension. | ||
13 | * If the data source module demands suspension, we want to be able to back | ||
14 | * up to the start of the current MCU. To do this, we copy state variables | ||
15 | * into local working storage, and update them back to the permanent | ||
16 | * storage only upon successful completion of an MCU. | ||
17 | */ | ||
18 | |||
19 | #define JPEG_INTERNALS | ||
20 | #include "jinclude.h" | ||
21 | #include "jpeglib.h" | ||
22 | |||
23 | |||
24 | /* Derived data constructed for each Huffman table */ | ||
25 | |||
26 | #define HUFF_LOOKAHEAD 8 /* # of bits of lookahead */ | ||
27 | |||
28 | typedef struct { | ||
29 | /* Basic tables: (element [0] of each array is unused) */ | ||
30 | INT32 maxcode[18]; /* largest code of length k (-1 if none) */ | ||
31 | /* (maxcode[17] is a sentinel to ensure jpeg_huff_decode terminates) */ | ||
32 | INT32 valoffset[17]; /* huffval[] offset for codes of length k */ | ||
33 | /* valoffset[k] = huffval[] index of 1st symbol of code length k, less | ||
34 | * the smallest code of length k; so given a code of length k, the | ||
35 | * corresponding symbol is huffval[code + valoffset[k]] | ||
36 | */ | ||
37 | |||
38 | /* Link to public Huffman table (needed only in jpeg_huff_decode) */ | ||
39 | JHUFF_TBL *pub; | ||
40 | |||
41 | /* Lookahead tables: indexed by the next HUFF_LOOKAHEAD bits of | ||
42 | * the input data stream. If the next Huffman code is no more | ||
43 | * than HUFF_LOOKAHEAD bits long, we can obtain its length and | ||
44 | * the corresponding symbol directly from these tables. | ||
45 | */ | ||
46 | int look_nbits[1<<HUFF_LOOKAHEAD]; /* # bits, or 0 if too long */ | ||
47 | UINT8 look_sym[1<<HUFF_LOOKAHEAD]; /* symbol, or unused */ | ||
48 | } d_derived_tbl; | ||
49 | |||
50 | |||
51 | /* | ||
52 | * Fetching the next N bits from the input stream is a time-critical operation | ||
53 | * for the Huffman decoders. We implement it with a combination of inline | ||
54 | * macros and out-of-line subroutines. Note that N (the number of bits | ||
55 | * demanded at one time) never exceeds 15 for JPEG use. | ||
56 | * | ||
57 | * We read source bytes into get_buffer and dole out bits as needed. | ||
58 | * If get_buffer already contains enough bits, they are fetched in-line | ||
59 | * by the macros CHECK_BIT_BUFFER and GET_BITS. When there aren't enough | ||
60 | * bits, jpeg_fill_bit_buffer is called; it will attempt to fill get_buffer | ||
61 | * as full as possible (not just to the number of bits needed; this | ||
62 | * prefetching reduces the overhead cost of calling jpeg_fill_bit_buffer). | ||
63 | * Note that jpeg_fill_bit_buffer may return FALSE to indicate suspension. | ||
64 | * On TRUE return, jpeg_fill_bit_buffer guarantees that get_buffer contains | ||
65 | * at least the requested number of bits --- dummy zeroes are inserted if | ||
66 | * necessary. | ||
67 | */ | ||
68 | |||
69 | typedef INT32 bit_buf_type; /* type of bit-extraction buffer */ | ||
70 | #define BIT_BUF_SIZE 32 /* size of buffer in bits */ | ||
71 | |||
72 | /* If long is > 32 bits on your machine, and shifting/masking longs is | ||
73 | * reasonably fast, making bit_buf_type be long and setting BIT_BUF_SIZE | ||
74 | * appropriately should be a win. Unfortunately we can't define the size | ||
75 | * with something like #define BIT_BUF_SIZE (sizeof(bit_buf_type)*8) | ||
76 | * because not all machines measure sizeof in 8-bit bytes. | ||
77 | */ | ||
78 | |||
79 | typedef struct { /* Bitreading state saved across MCUs */ | ||
80 | bit_buf_type get_buffer; /* current bit-extraction buffer */ | ||
81 | int bits_left; /* # of unused bits in it */ | ||
82 | } bitread_perm_state; | ||
83 | |||
84 | typedef struct { /* Bitreading working state within an MCU */ | ||
85 | /* Current data source location */ | ||
86 | /* We need a copy, rather than munging the original, in case of suspension */ | ||
87 | const JOCTET * next_input_byte; /* => next byte to read from source */ | ||
88 | size_t bytes_in_buffer; /* # of bytes remaining in source buffer */ | ||
89 | /* Bit input buffer --- note these values are kept in register variables, | ||
90 | * not in this struct, inside the inner loops. | ||
91 | */ | ||
92 | bit_buf_type get_buffer; /* current bit-extraction buffer */ | ||
93 | int bits_left; /* # of unused bits in it */ | ||
94 | /* Pointer needed by jpeg_fill_bit_buffer. */ | ||
95 | j_decompress_ptr cinfo; /* back link to decompress master record */ | ||
96 | } bitread_working_state; | ||
97 | |||
98 | /* Macros to declare and load/save bitread local variables. */ | ||
99 | #define BITREAD_STATE_VARS \ | ||
100 | register bit_buf_type get_buffer; \ | ||
101 | register int bits_left; \ | ||
102 | bitread_working_state br_state | ||
103 | |||
104 | #define BITREAD_LOAD_STATE(cinfop,permstate) \ | ||
105 | br_state.cinfo = cinfop; \ | ||
106 | br_state.next_input_byte = cinfop->src->next_input_byte; \ | ||
107 | br_state.bytes_in_buffer = cinfop->src->bytes_in_buffer; \ | ||
108 | get_buffer = permstate.get_buffer; \ | ||
109 | bits_left = permstate.bits_left; | ||
110 | |||
111 | #define BITREAD_SAVE_STATE(cinfop,permstate) \ | ||
112 | cinfop->src->next_input_byte = br_state.next_input_byte; \ | ||
113 | cinfop->src->bytes_in_buffer = br_state.bytes_in_buffer; \ | ||
114 | permstate.get_buffer = get_buffer; \ | ||
115 | permstate.bits_left = bits_left | ||
116 | |||
117 | /* | ||
118 | * These macros provide the in-line portion of bit fetching. | ||
119 | * Use CHECK_BIT_BUFFER to ensure there are N bits in get_buffer | ||
120 | * before using GET_BITS, PEEK_BITS, or DROP_BITS. | ||
121 | * The variables get_buffer and bits_left are assumed to be locals, | ||
122 | * but the state struct might not be (jpeg_huff_decode needs this). | ||
123 | * CHECK_BIT_BUFFER(state,n,action); | ||
124 | * Ensure there are N bits in get_buffer; if suspend, take action. | ||
125 | * val = GET_BITS(n); | ||
126 | * Fetch next N bits. | ||
127 | * val = PEEK_BITS(n); | ||
128 | * Fetch next N bits without removing them from the buffer. | ||
129 | * DROP_BITS(n); | ||
130 | * Discard next N bits. | ||
131 | * The value N should be a simple variable, not an expression, because it | ||
132 | * is evaluated multiple times. | ||
133 | */ | ||
134 | |||
135 | #define CHECK_BIT_BUFFER(state,nbits,action) \ | ||
136 | { if (bits_left < (nbits)) { \ | ||
137 | if (! jpeg_fill_bit_buffer(&(state),get_buffer,bits_left,nbits)) \ | ||
138 | { action; } \ | ||
139 | get_buffer = (state).get_buffer; bits_left = (state).bits_left; } } | ||
140 | |||
141 | #define GET_BITS(nbits) \ | ||
142 | (((int) (get_buffer >> (bits_left -= (nbits)))) & BIT_MASK(nbits)) | ||
143 | |||
144 | #define PEEK_BITS(nbits) \ | ||
145 | (((int) (get_buffer >> (bits_left - (nbits)))) & BIT_MASK(nbits)) | ||
146 | |||
147 | #define DROP_BITS(nbits) \ | ||
148 | (bits_left -= (nbits)) | ||
149 | |||
150 | |||
151 | /* | ||
152 | * Code for extracting next Huffman-coded symbol from input bit stream. | ||
153 | * Again, this is time-critical and we make the main paths be macros. | ||
154 | * | ||
155 | * We use a lookahead table to process codes of up to HUFF_LOOKAHEAD bits | ||
156 | * without looping. Usually, more than 95% of the Huffman codes will be 8 | ||
157 | * or fewer bits long. The few overlength codes are handled with a loop, | ||
158 | * which need not be inline code. | ||
159 | * | ||
160 | * Notes about the HUFF_DECODE macro: | ||
161 | * 1. Near the end of the data segment, we may fail to get enough bits | ||
162 | * for a lookahead. In that case, we do it the hard way. | ||
163 | * 2. If the lookahead table contains no entry, the next code must be | ||
164 | * more than HUFF_LOOKAHEAD bits long. | ||
165 | * 3. jpeg_huff_decode returns -1 if forced to suspend. | ||
166 | */ | ||
167 | |||
168 | #define HUFF_DECODE(result,state,htbl,failaction,slowlabel) \ | ||
169 | { register int nb, look; \ | ||
170 | if (bits_left < HUFF_LOOKAHEAD) { \ | ||
171 | if (! jpeg_fill_bit_buffer(&state,get_buffer,bits_left, 0)) {failaction;} \ | ||
172 | get_buffer = state.get_buffer; bits_left = state.bits_left; \ | ||
173 | if (bits_left < HUFF_LOOKAHEAD) { \ | ||
174 | nb = 1; goto slowlabel; \ | ||
175 | } \ | ||
176 | } \ | ||
177 | look = PEEK_BITS(HUFF_LOOKAHEAD); \ | ||
178 | if ((nb = htbl->look_nbits[look]) != 0) { \ | ||
179 | DROP_BITS(nb); \ | ||
180 | result = htbl->look_sym[look]; \ | ||
181 | } else { \ | ||
182 | nb = HUFF_LOOKAHEAD+1; \ | ||
183 | slowlabel: \ | ||
184 | if ((result=jpeg_huff_decode(&state,get_buffer,bits_left,htbl,nb)) < 0) \ | ||
185 | { failaction; } \ | ||
186 | get_buffer = state.get_buffer; bits_left = state.bits_left; \ | ||
187 | } \ | ||
188 | } | ||
189 | |||
190 | |||
191 | /* | ||
192 | * Expanded entropy decoder object for Huffman decoding. | ||
193 | * | ||
194 | * The savable_state subrecord contains fields that change within an MCU, | ||
195 | * but must not be updated permanently until we complete the MCU. | ||
196 | */ | ||
197 | |||
198 | typedef struct { | ||
199 | unsigned int EOBRUN; /* remaining EOBs in EOBRUN */ | ||
200 | int last_dc_val[MAX_COMPS_IN_SCAN]; /* last DC coef for each component */ | ||
201 | } savable_state; | ||
202 | |||
203 | /* This macro is to work around compilers with missing or broken | ||
204 | * structure assignment. You'll need to fix this code if you have | ||
205 | * such a compiler and you change MAX_COMPS_IN_SCAN. | ||
206 | */ | ||
207 | |||
208 | #ifndef NO_STRUCT_ASSIGN | ||
209 | #define ASSIGN_STATE(dest,src) ((dest) = (src)) | ||
210 | #else | ||
211 | #if MAX_COMPS_IN_SCAN == 4 | ||
212 | #define ASSIGN_STATE(dest,src) \ | ||
213 | ((dest).EOBRUN = (src).EOBRUN, \ | ||
214 | (dest).last_dc_val[0] = (src).last_dc_val[0], \ | ||
215 | (dest).last_dc_val[1] = (src).last_dc_val[1], \ | ||
216 | (dest).last_dc_val[2] = (src).last_dc_val[2], \ | ||
217 | (dest).last_dc_val[3] = (src).last_dc_val[3]) | ||
218 | #endif | ||
219 | #endif | ||
220 | |||
221 | |||
222 | typedef struct { | ||
223 | struct jpeg_entropy_decoder pub; /* public fields */ | ||
224 | |||
225 | /* These fields are loaded into local variables at start of each MCU. | ||
226 | * In case of suspension, we exit WITHOUT updating them. | ||
227 | */ | ||
228 | bitread_perm_state bitstate; /* Bit buffer at start of MCU */ | ||
229 | savable_state saved; /* Other state at start of MCU */ | ||
230 | |||
231 | /* These fields are NOT loaded into local working state. */ | ||
232 | boolean insufficient_data; /* set TRUE after emitting warning */ | ||
233 | unsigned int restarts_to_go; /* MCUs left in this restart interval */ | ||
234 | |||
235 | /* Following two fields used only in progressive mode */ | ||
236 | |||
237 | /* Pointers to derived tables (these workspaces have image lifespan) */ | ||
238 | d_derived_tbl * derived_tbls[NUM_HUFF_TBLS]; | ||
239 | |||
240 | d_derived_tbl * ac_derived_tbl; /* active table during an AC scan */ | ||
241 | |||
242 | /* Following fields used only in sequential mode */ | ||
243 | |||
244 | /* Pointers to derived tables (these workspaces have image lifespan) */ | ||
245 | d_derived_tbl * dc_derived_tbls[NUM_HUFF_TBLS]; | ||
246 | d_derived_tbl * ac_derived_tbls[NUM_HUFF_TBLS]; | ||
247 | |||
248 | /* Precalculated info set up by start_pass for use in decode_mcu: */ | ||
249 | |||
250 | /* Pointers to derived tables to be used for each block within an MCU */ | ||
251 | d_derived_tbl * dc_cur_tbls[D_MAX_BLOCKS_IN_MCU]; | ||
252 | d_derived_tbl * ac_cur_tbls[D_MAX_BLOCKS_IN_MCU]; | ||
253 | /* Whether we care about the DC and AC coefficient values for each block */ | ||
254 | int coef_limit[D_MAX_BLOCKS_IN_MCU]; | ||
255 | } huff_entropy_decoder; | ||
256 | |||
257 | typedef huff_entropy_decoder * huff_entropy_ptr; | ||
258 | |||
259 | |||
260 | static const int jpeg_zigzag_order[8][8] = { | ||
261 | { 0, 1, 5, 6, 14, 15, 27, 28 }, | ||
262 | { 2, 4, 7, 13, 16, 26, 29, 42 }, | ||
263 | { 3, 8, 12, 17, 25, 30, 41, 43 }, | ||
264 | { 9, 11, 18, 24, 31, 40, 44, 53 }, | ||
265 | { 10, 19, 23, 32, 39, 45, 52, 54 }, | ||
266 | { 20, 22, 33, 38, 46, 51, 55, 60 }, | ||
267 | { 21, 34, 37, 47, 50, 56, 59, 61 }, | ||
268 | { 35, 36, 48, 49, 57, 58, 62, 63 } | ||
269 | }; | ||
270 | |||
271 | static const int jpeg_zigzag_order7[7][7] = { | ||
272 | { 0, 1, 5, 6, 14, 15, 27 }, | ||
273 | { 2, 4, 7, 13, 16, 26, 28 }, | ||
274 | { 3, 8, 12, 17, 25, 29, 38 }, | ||
275 | { 9, 11, 18, 24, 30, 37, 39 }, | ||
276 | { 10, 19, 23, 31, 36, 40, 45 }, | ||
277 | { 20, 22, 32, 35, 41, 44, 46 }, | ||
278 | { 21, 33, 34, 42, 43, 47, 48 } | ||
279 | }; | ||
280 | |||
281 | static const int jpeg_zigzag_order6[6][6] = { | ||
282 | { 0, 1, 5, 6, 14, 15 }, | ||
283 | { 2, 4, 7, 13, 16, 25 }, | ||
284 | { 3, 8, 12, 17, 24, 26 }, | ||
285 | { 9, 11, 18, 23, 27, 32 }, | ||
286 | { 10, 19, 22, 28, 31, 33 }, | ||
287 | { 20, 21, 29, 30, 34, 35 } | ||
288 | }; | ||
289 | |||
290 | static const int jpeg_zigzag_order5[5][5] = { | ||
291 | { 0, 1, 5, 6, 14 }, | ||
292 | { 2, 4, 7, 13, 15 }, | ||
293 | { 3, 8, 12, 16, 21 }, | ||
294 | { 9, 11, 17, 20, 22 }, | ||
295 | { 10, 18, 19, 23, 24 } | ||
296 | }; | ||
297 | |||
298 | static const int jpeg_zigzag_order4[4][4] = { | ||
299 | { 0, 1, 5, 6 }, | ||
300 | { 2, 4, 7, 12 }, | ||
301 | { 3, 8, 11, 13 }, | ||
302 | { 9, 10, 14, 15 } | ||
303 | }; | ||
304 | |||
305 | static const int jpeg_zigzag_order3[3][3] = { | ||
306 | { 0, 1, 5 }, | ||
307 | { 2, 4, 6 }, | ||
308 | { 3, 7, 8 } | ||
309 | }; | ||
310 | |||
311 | static const int jpeg_zigzag_order2[2][2] = { | ||
312 | { 0, 1 }, | ||
313 | { 2, 3 } | ||
314 | }; | ||
315 | |||
316 | |||
317 | /* | ||
318 | * Compute the derived values for a Huffman table. | ||
319 | * This routine also performs some validation checks on the table. | ||
320 | */ | ||
321 | |||
322 | LOCAL(void) | ||
323 | jpeg_make_d_derived_tbl (j_decompress_ptr cinfo, boolean isDC, int tblno, | ||
324 | d_derived_tbl ** pdtbl) | ||
325 | { | ||
326 | JHUFF_TBL *htbl; | ||
327 | d_derived_tbl *dtbl; | ||
328 | int p, i, l, si, numsymbols; | ||
329 | int lookbits, ctr; | ||
330 | char huffsize[257]; | ||
331 | unsigned int huffcode[257]; | ||
332 | unsigned int code; | ||
333 | |||
334 | /* Note that huffsize[] and huffcode[] are filled in code-length order, | ||
335 | * paralleling the order of the symbols themselves in htbl->huffval[]. | ||
336 | */ | ||
337 | |||
338 | /* Find the input Huffman table */ | ||
339 | if (tblno < 0 || tblno >= NUM_HUFF_TBLS) | ||
340 | ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, tblno); | ||
341 | htbl = | ||
342 | isDC ? cinfo->dc_huff_tbl_ptrs[tblno] : cinfo->ac_huff_tbl_ptrs[tblno]; | ||
343 | if (htbl == NULL) | ||
344 | ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, tblno); | ||
345 | |||
346 | /* Allocate a workspace if we haven't already done so. */ | ||
347 | if (*pdtbl == NULL) | ||
348 | *pdtbl = (d_derived_tbl *) | ||
349 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, | ||
350 | SIZEOF(d_derived_tbl)); | ||
351 | dtbl = *pdtbl; | ||
352 | dtbl->pub = htbl; /* fill in back link */ | ||
353 | |||
354 | /* Figure C.1: make table of Huffman code length for each symbol */ | ||
355 | |||
356 | p = 0; | ||
357 | for (l = 1; l <= 16; l++) { | ||
358 | i = (int) htbl->bits[l]; | ||
359 | if (i < 0 || p + i > 256) /* protect against table overrun */ | ||
360 | ERREXIT(cinfo, JERR_BAD_HUFF_TABLE); | ||
361 | while (i--) | ||
362 | huffsize[p++] = (char) l; | ||
363 | } | ||
364 | huffsize[p] = 0; | ||
365 | numsymbols = p; | ||
366 | |||
367 | /* Figure C.2: generate the codes themselves */ | ||
368 | /* We also validate that the counts represent a legal Huffman code tree. */ | ||
369 | |||
370 | code = 0; | ||
371 | si = huffsize[0]; | ||
372 | p = 0; | ||
373 | while (huffsize[p]) { | ||
374 | while (((int) huffsize[p]) == si) { | ||
375 | huffcode[p++] = code; | ||
376 | code++; | ||
377 | } | ||
378 | /* code is now 1 more than the last code used for codelength si; but | ||
379 | * it must still fit in si bits, since no code is allowed to be all ones. | ||
380 | */ | ||
381 | if (((INT32) code) >= (((INT32) 1) << si)) | ||
382 | ERREXIT(cinfo, JERR_BAD_HUFF_TABLE); | ||
383 | code <<= 1; | ||
384 | si++; | ||
385 | } | ||
386 | |||
387 | /* Figure F.15: generate decoding tables for bit-sequential decoding */ | ||
388 | |||
389 | p = 0; | ||
390 | for (l = 1; l <= 16; l++) { | ||
391 | if (htbl->bits[l]) { | ||
392 | /* valoffset[l] = huffval[] index of 1st symbol of code length l, | ||
393 | * minus the minimum code of length l | ||
394 | */ | ||
395 | dtbl->valoffset[l] = (INT32) p - (INT32) huffcode[p]; | ||
396 | p += htbl->bits[l]; | ||
397 | dtbl->maxcode[l] = huffcode[p-1]; /* maximum code of length l */ | ||
398 | } else { | ||
399 | dtbl->maxcode[l] = -1; /* -1 if no codes of this length */ | ||
400 | } | ||
401 | } | ||
402 | dtbl->maxcode[17] = 0xFFFFFL; /* ensures jpeg_huff_decode terminates */ | ||
403 | |||
404 | /* Compute lookahead tables to speed up decoding. | ||
405 | * First we set all the table entries to 0, indicating "too long"; | ||
406 | * then we iterate through the Huffman codes that are short enough and | ||
407 | * fill in all the entries that correspond to bit sequences starting | ||
408 | * with that code. | ||
409 | */ | ||
410 | |||
411 | MEMZERO(dtbl->look_nbits, SIZEOF(dtbl->look_nbits)); | ||
412 | |||
413 | p = 0; | ||
414 | for (l = 1; l <= HUFF_LOOKAHEAD; l++) { | ||
415 | for (i = 1; i <= (int) htbl->bits[l]; i++, p++) { | ||
416 | /* l = current code's length, p = its index in huffcode[] & huffval[]. */ | ||
417 | /* Generate left-justified code followed by all possible bit sequences */ | ||
418 | lookbits = huffcode[p] << (HUFF_LOOKAHEAD-l); | ||
419 | for (ctr = 1 << (HUFF_LOOKAHEAD-l); ctr > 0; ctr--) { | ||
420 | dtbl->look_nbits[lookbits] = l; | ||
421 | dtbl->look_sym[lookbits] = htbl->huffval[p]; | ||
422 | lookbits++; | ||
423 | } | ||
424 | } | ||
425 | } | ||
426 | |||
427 | /* Validate symbols as being reasonable. | ||
428 | * For AC tables, we make no check, but accept all byte values 0..255. | ||
429 | * For DC tables, we require the symbols to be in range 0..15. | ||
430 | * (Tighter bounds could be applied depending on the data depth and mode, | ||
431 | * but this is sufficient to ensure safe decoding.) | ||
432 | */ | ||
433 | if (isDC) { | ||
434 | for (i = 0; i < numsymbols; i++) { | ||
435 | int sym = htbl->huffval[i]; | ||
436 | if (sym < 0 || sym > 15) | ||
437 | ERREXIT(cinfo, JERR_BAD_HUFF_TABLE); | ||
438 | } | ||
439 | } | ||
440 | } | ||
441 | |||
442 | |||
443 | /* | ||
444 | * Out-of-line code for bit fetching. | ||
445 | * Note: current values of get_buffer and bits_left are passed as parameters, | ||
446 | * but are returned in the corresponding fields of the state struct. | ||
447 | * | ||
448 | * On most machines MIN_GET_BITS should be 25 to allow the full 32-bit width | ||
449 | * of get_buffer to be used. (On machines with wider words, an even larger | ||
450 | * buffer could be used.) However, on some machines 32-bit shifts are | ||
451 | * quite slow and take time proportional to the number of places shifted. | ||
452 | * (This is true with most PC compilers, for instance.) In this case it may | ||
453 | * be a win to set MIN_GET_BITS to the minimum value of 15. This reduces the | ||
454 | * average shift distance at the cost of more calls to jpeg_fill_bit_buffer. | ||
455 | */ | ||
456 | |||
457 | #ifdef SLOW_SHIFT_32 | ||
458 | #define MIN_GET_BITS 15 /* minimum allowable value */ | ||
459 | #else | ||
460 | #define MIN_GET_BITS (BIT_BUF_SIZE-7) | ||
461 | #endif | ||
462 | |||
463 | |||
464 | LOCAL(boolean) | ||
465 | jpeg_fill_bit_buffer (bitread_working_state * state, | ||
466 | register bit_buf_type get_buffer, register int bits_left, | ||
467 | int nbits) | ||
468 | /* Load up the bit buffer to a depth of at least nbits */ | ||
469 | { | ||
470 | /* Copy heavily used state fields into locals (hopefully registers) */ | ||
471 | register const JOCTET * next_input_byte = state->next_input_byte; | ||
472 | register size_t bytes_in_buffer = state->bytes_in_buffer; | ||
473 | j_decompress_ptr cinfo = state->cinfo; | ||
474 | |||
475 | /* Attempt to load at least MIN_GET_BITS bits into get_buffer. */ | ||
476 | /* (It is assumed that no request will be for more than that many bits.) */ | ||
477 | /* We fail to do so only if we hit a marker or are forced to suspend. */ | ||
478 | |||
479 | if (cinfo->unread_marker == 0) { /* cannot advance past a marker */ | ||
480 | while (bits_left < MIN_GET_BITS) { | ||
481 | register int c; | ||
482 | |||
483 | /* Attempt to read a byte */ | ||
484 | if (bytes_in_buffer == 0) { | ||
485 | if (! (*cinfo->src->fill_input_buffer) (cinfo)) | ||
486 | return FALSE; | ||
487 | next_input_byte = cinfo->src->next_input_byte; | ||
488 | bytes_in_buffer = cinfo->src->bytes_in_buffer; | ||
489 | } | ||
490 | bytes_in_buffer--; | ||
491 | c = GETJOCTET(*next_input_byte++); | ||
492 | |||
493 | /* If it's 0xFF, check and discard stuffed zero byte */ | ||
494 | if (c == 0xFF) { | ||
495 | /* Loop here to discard any padding FF's on terminating marker, | ||
496 | * so that we can save a valid unread_marker value. NOTE: we will | ||
497 | * accept multiple FF's followed by a 0 as meaning a single FF data | ||
498 | * byte. This data pattern is not valid according to the standard. | ||
499 | */ | ||
500 | do { | ||
501 | if (bytes_in_buffer == 0) { | ||
502 | if (! (*cinfo->src->fill_input_buffer) (cinfo)) | ||
503 | return FALSE; | ||
504 | next_input_byte = cinfo->src->next_input_byte; | ||
505 | bytes_in_buffer = cinfo->src->bytes_in_buffer; | ||
506 | } | ||
507 | bytes_in_buffer--; | ||
508 | c = GETJOCTET(*next_input_byte++); | ||
509 | } while (c == 0xFF); | ||
510 | |||
511 | if (c == 0) { | ||
512 | /* Found FF/00, which represents an FF data byte */ | ||
513 | c = 0xFF; | ||
514 | } else { | ||
515 | /* Oops, it's actually a marker indicating end of compressed data. | ||
516 | * Save the marker code for later use. | ||
517 | * Fine point: it might appear that we should save the marker into | ||
518 | * bitread working state, not straight into permanent state. But | ||
519 | * once we have hit a marker, we cannot need to suspend within the | ||
520 | * current MCU, because we will read no more bytes from the data | ||
521 | * source. So it is OK to update permanent state right away. | ||
522 | */ | ||
523 | cinfo->unread_marker = c; | ||
524 | /* See if we need to insert some fake zero bits. */ | ||
525 | goto no_more_bytes; | ||
526 | } | ||
527 | } | ||
528 | |||
529 | /* OK, load c into get_buffer */ | ||
530 | get_buffer = (get_buffer << 8) | c; | ||
531 | bits_left += 8; | ||
532 | } /* end while */ | ||
533 | } else { | ||
534 | no_more_bytes: | ||
535 | /* We get here if we've read the marker that terminates the compressed | ||
536 | * data segment. There should be enough bits in the buffer register | ||
537 | * to satisfy the request; if so, no problem. | ||
538 | */ | ||
539 | if (nbits > bits_left) { | ||
540 | /* Uh-oh. Report corrupted data to user and stuff zeroes into | ||
541 | * the data stream, so that we can produce some kind of image. | ||
542 | * We use a nonvolatile flag to ensure that only one warning message | ||
543 | * appears per data segment. | ||
544 | */ | ||
545 | if (! ((huff_entropy_ptr) cinfo->entropy)->insufficient_data) { | ||
546 | WARNMS(cinfo, JWRN_HIT_MARKER); | ||
547 | ((huff_entropy_ptr) cinfo->entropy)->insufficient_data = TRUE; | ||
548 | } | ||
549 | /* Fill the buffer with zero bits */ | ||
550 | get_buffer <<= MIN_GET_BITS - bits_left; | ||
551 | bits_left = MIN_GET_BITS; | ||
552 | } | ||
553 | } | ||
554 | |||
555 | /* Unload the local registers */ | ||
556 | state->next_input_byte = next_input_byte; | ||
557 | state->bytes_in_buffer = bytes_in_buffer; | ||
558 | state->get_buffer = get_buffer; | ||
559 | state->bits_left = bits_left; | ||
560 | |||
561 | return TRUE; | ||
562 | } | ||
563 | |||
564 | |||
565 | /* | ||
566 | * Figure F.12: extend sign bit. | ||
567 | * On some machines, a shift and sub will be faster than a table lookup. | ||
568 | */ | ||
569 | |||
570 | #ifdef AVOID_TABLES | ||
571 | |||
572 | #define BIT_MASK(nbits) ((1<<(nbits))-1) | ||
573 | #define HUFF_EXTEND(x,s) ((x) < (1<<((s)-1)) ? (x) - ((1<<(s))-1) : (x)) | ||
574 | |||
575 | #else | ||
576 | |||
577 | #define BIT_MASK(nbits) bmask[nbits] | ||
578 | #define HUFF_EXTEND(x,s) ((x) <= bmask[(s) - 1] ? (x) - bmask[s] : (x)) | ||
579 | |||
580 | static const int bmask[16] = /* bmask[n] is mask for n rightmost bits */ | ||
581 | { 0, 0x0001, 0x0003, 0x0007, 0x000F, 0x001F, 0x003F, 0x007F, 0x00FF, | ||
582 | 0x01FF, 0x03FF, 0x07FF, 0x0FFF, 0x1FFF, 0x3FFF, 0x7FFF }; | ||
583 | |||
584 | #endif /* AVOID_TABLES */ | ||
585 | |||
586 | |||
587 | /* | ||
588 | * Out-of-line code for Huffman code decoding. | ||
589 | */ | ||
590 | |||
591 | LOCAL(int) | ||
592 | jpeg_huff_decode (bitread_working_state * state, | ||
593 | register bit_buf_type get_buffer, register int bits_left, | ||
594 | d_derived_tbl * htbl, int min_bits) | ||
595 | { | ||
596 | register int l = min_bits; | ||
597 | register INT32 code; | ||
598 | |||
599 | /* HUFF_DECODE has determined that the code is at least min_bits */ | ||
600 | /* bits long, so fetch that many bits in one swoop. */ | ||
601 | |||
602 | CHECK_BIT_BUFFER(*state, l, return -1); | ||
603 | code = GET_BITS(l); | ||
604 | |||
605 | /* Collect the rest of the Huffman code one bit at a time. */ | ||
606 | /* This is per Figure F.16 in the JPEG spec. */ | ||
607 | |||
608 | while (code > htbl->maxcode[l]) { | ||
609 | code <<= 1; | ||
610 | CHECK_BIT_BUFFER(*state, 1, return -1); | ||
611 | code |= GET_BITS(1); | ||
612 | l++; | ||
613 | } | ||
614 | |||
615 | /* Unload the local registers */ | ||
616 | state->get_buffer = get_buffer; | ||
617 | state->bits_left = bits_left; | ||
618 | |||
619 | /* With garbage input we may reach the sentinel value l = 17. */ | ||
620 | |||
621 | if (l > 16) { | ||
622 | WARNMS(state->cinfo, JWRN_HUFF_BAD_CODE); | ||
623 | return 0; /* fake a zero as the safest result */ | ||
624 | } | ||
625 | |||
626 | return htbl->pub->huffval[ (int) (code + htbl->valoffset[l]) ]; | ||
627 | } | ||
628 | |||
629 | |||
630 | /* | ||
631 | * Check for a restart marker & resynchronize decoder. | ||
632 | * Returns FALSE if must suspend. | ||
633 | */ | ||
634 | |||
635 | LOCAL(boolean) | ||
636 | process_restart (j_decompress_ptr cinfo) | ||
637 | { | ||
638 | huff_entropy_ptr entropy = (huff_entropy_ptr) cinfo->entropy; | ||
639 | int ci; | ||
640 | |||
641 | /* Throw away any unused bits remaining in bit buffer; */ | ||
642 | /* include any full bytes in next_marker's count of discarded bytes */ | ||
643 | cinfo->marker->discarded_bytes += entropy->bitstate.bits_left / 8; | ||
644 | entropy->bitstate.bits_left = 0; | ||
645 | |||
646 | /* Advance past the RSTn marker */ | ||
647 | if (! (*cinfo->marker->read_restart_marker) (cinfo)) | ||
648 | return FALSE; | ||
649 | |||
650 | /* Re-initialize DC predictions to 0 */ | ||
651 | for (ci = 0; ci < cinfo->comps_in_scan; ci++) | ||
652 | entropy->saved.last_dc_val[ci] = 0; | ||
653 | /* Re-init EOB run count, too */ | ||
654 | entropy->saved.EOBRUN = 0; | ||
655 | |||
656 | /* Reset restart counter */ | ||
657 | entropy->restarts_to_go = cinfo->restart_interval; | ||
658 | |||
659 | /* Reset out-of-data flag, unless read_restart_marker left us smack up | ||
660 | * against a marker. In that case we will end up treating the next data | ||
661 | * segment as empty, and we can avoid producing bogus output pixels by | ||
662 | * leaving the flag set. | ||
663 | */ | ||
664 | if (cinfo->unread_marker == 0) | ||
665 | entropy->insufficient_data = FALSE; | ||
666 | |||
667 | return TRUE; | ||
668 | } | ||
669 | |||
670 | |||
671 | /* | ||
672 | * Huffman MCU decoding. | ||
673 | * Each of these routines decodes and returns one MCU's worth of | ||
674 | * Huffman-compressed coefficients. | ||
675 | * The coefficients are reordered from zigzag order into natural array order, | ||
676 | * but are not dequantized. | ||
677 | * | ||
678 | * The i'th block of the MCU is stored into the block pointed to by | ||
679 | * MCU_data[i]. WE ASSUME THIS AREA IS INITIALLY ZEROED BY THE CALLER. | ||
680 | * (Wholesale zeroing is usually a little faster than retail...) | ||
681 | * | ||
682 | * We return FALSE if data source requested suspension. In that case no | ||
683 | * changes have been made to permanent state. (Exception: some output | ||
684 | * coefficients may already have been assigned. This is harmless for | ||
685 | * spectral selection, since we'll just re-assign them on the next call. | ||
686 | * Successive approximation AC refinement has to be more careful, however.) | ||
687 | */ | ||
688 | |||
689 | /* | ||
690 | * MCU decoding for DC initial scan (either spectral selection, | ||
691 | * or first pass of successive approximation). | ||
692 | */ | ||
693 | |||
694 | METHODDEF(boolean) | ||
695 | decode_mcu_DC_first (j_decompress_ptr cinfo, JBLOCKROW *MCU_data) | ||
696 | { | ||
697 | huff_entropy_ptr entropy = (huff_entropy_ptr) cinfo->entropy; | ||
698 | int Al = cinfo->Al; | ||
699 | register int s, r; | ||
700 | int blkn, ci; | ||
701 | JBLOCKROW block; | ||
702 | BITREAD_STATE_VARS; | ||
703 | savable_state state; | ||
704 | d_derived_tbl * tbl; | ||
705 | jpeg_component_info * compptr; | ||
706 | |||
707 | /* Process restart marker if needed; may have to suspend */ | ||
708 | if (cinfo->restart_interval) { | ||
709 | if (entropy->restarts_to_go == 0) | ||
710 | if (! process_restart(cinfo)) | ||
711 | return FALSE; | ||
712 | } | ||
713 | |||
714 | /* If we've run out of data, just leave the MCU set to zeroes. | ||
715 | * This way, we return uniform gray for the remainder of the segment. | ||
716 | */ | ||
717 | if (! entropy->insufficient_data) { | ||
718 | |||
719 | /* Load up working state */ | ||
720 | BITREAD_LOAD_STATE(cinfo,entropy->bitstate); | ||
721 | ASSIGN_STATE(state, entropy->saved); | ||
722 | |||
723 | /* Outer loop handles each block in the MCU */ | ||
724 | |||
725 | for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) { | ||
726 | block = MCU_data[blkn]; | ||
727 | ci = cinfo->MCU_membership[blkn]; | ||
728 | compptr = cinfo->cur_comp_info[ci]; | ||
729 | tbl = entropy->derived_tbls[compptr->dc_tbl_no]; | ||
730 | |||
731 | /* Decode a single block's worth of coefficients */ | ||
732 | |||
733 | /* Section F.2.2.1: decode the DC coefficient difference */ | ||
734 | HUFF_DECODE(s, br_state, tbl, return FALSE, label1); | ||
735 | if (s) { | ||
736 | CHECK_BIT_BUFFER(br_state, s, return FALSE); | ||
737 | r = GET_BITS(s); | ||
738 | s = HUFF_EXTEND(r, s); | ||
739 | } | ||
740 | |||
741 | /* Convert DC difference to actual value, update last_dc_val */ | ||
742 | s += state.last_dc_val[ci]; | ||
743 | state.last_dc_val[ci] = s; | ||
744 | /* Scale and output the coefficient (assumes jpeg_natural_order[0]=0) */ | ||
745 | (*block)[0] = (JCOEF) (s << Al); | ||
746 | } | ||
747 | |||
748 | /* Completed MCU, so update state */ | ||
749 | BITREAD_SAVE_STATE(cinfo,entropy->bitstate); | ||
750 | ASSIGN_STATE(entropy->saved, state); | ||
751 | } | ||
752 | |||
753 | /* Account for restart interval (no-op if not using restarts) */ | ||
754 | entropy->restarts_to_go--; | ||
755 | |||
756 | return TRUE; | ||
757 | } | ||
758 | |||
759 | |||
760 | /* | ||
761 | * MCU decoding for AC initial scan (either spectral selection, | ||
762 | * or first pass of successive approximation). | ||
763 | */ | ||
764 | |||
765 | METHODDEF(boolean) | ||
766 | decode_mcu_AC_first (j_decompress_ptr cinfo, JBLOCKROW *MCU_data) | ||
767 | { | ||
768 | huff_entropy_ptr entropy = (huff_entropy_ptr) cinfo->entropy; | ||
769 | register int s, k, r; | ||
770 | unsigned int EOBRUN; | ||
771 | int Se, Al; | ||
772 | const int * natural_order; | ||
773 | JBLOCKROW block; | ||
774 | BITREAD_STATE_VARS; | ||
775 | d_derived_tbl * tbl; | ||
776 | |||
777 | /* Process restart marker if needed; may have to suspend */ | ||
778 | if (cinfo->restart_interval) { | ||
779 | if (entropy->restarts_to_go == 0) | ||
780 | if (! process_restart(cinfo)) | ||
781 | return FALSE; | ||
782 | } | ||
783 | |||
784 | /* If we've run out of data, just leave the MCU set to zeroes. | ||
785 | * This way, we return uniform gray for the remainder of the segment. | ||
786 | */ | ||
787 | if (! entropy->insufficient_data) { | ||
788 | |||
789 | Se = cinfo->Se; | ||
790 | Al = cinfo->Al; | ||
791 | natural_order = cinfo->natural_order; | ||
792 | |||
793 | /* Load up working state. | ||
794 | * We can avoid loading/saving bitread state if in an EOB run. | ||
795 | */ | ||
796 | EOBRUN = entropy->saved.EOBRUN; /* only part of saved state we need */ | ||
797 | |||
798 | /* There is always only one block per MCU */ | ||
799 | |||
800 | if (EOBRUN > 0) /* if it's a band of zeroes... */ | ||
801 | EOBRUN--; /* ...process it now (we do nothing) */ | ||
802 | else { | ||
803 | BITREAD_LOAD_STATE(cinfo,entropy->bitstate); | ||
804 | block = MCU_data[0]; | ||
805 | tbl = entropy->ac_derived_tbl; | ||
806 | |||
807 | for (k = cinfo->Ss; k <= Se; k++) { | ||
808 | HUFF_DECODE(s, br_state, tbl, return FALSE, label2); | ||
809 | r = s >> 4; | ||
810 | s &= 15; | ||
811 | if (s) { | ||
812 | k += r; | ||
813 | CHECK_BIT_BUFFER(br_state, s, return FALSE); | ||
814 | r = GET_BITS(s); | ||
815 | s = HUFF_EXTEND(r, s); | ||
816 | /* Scale and output coefficient in natural (dezigzagged) order */ | ||
817 | (*block)[natural_order[k]] = (JCOEF) (s << Al); | ||
818 | } else { | ||
819 | if (r == 15) { /* ZRL */ | ||
820 | k += 15; /* skip 15 zeroes in band */ | ||
821 | } else { /* EOBr, run length is 2^r + appended bits */ | ||
822 | EOBRUN = 1 << r; | ||
823 | if (r) { /* EOBr, r > 0 */ | ||
824 | CHECK_BIT_BUFFER(br_state, r, return FALSE); | ||
825 | r = GET_BITS(r); | ||
826 | EOBRUN += r; | ||
827 | } | ||
828 | EOBRUN--; /* this band is processed at this moment */ | ||
829 | break; /* force end-of-band */ | ||
830 | } | ||
831 | } | ||
832 | } | ||
833 | |||
834 | BITREAD_SAVE_STATE(cinfo,entropy->bitstate); | ||
835 | } | ||
836 | |||
837 | /* Completed MCU, so update state */ | ||
838 | entropy->saved.EOBRUN = EOBRUN; /* only part of saved state we need */ | ||
839 | } | ||
840 | |||
841 | /* Account for restart interval (no-op if not using restarts) */ | ||
842 | entropy->restarts_to_go--; | ||
843 | |||
844 | return TRUE; | ||
845 | } | ||
846 | |||
847 | |||
848 | /* | ||
849 | * MCU decoding for DC successive approximation refinement scan. | ||
850 | * Note: we assume such scans can be multi-component, although the spec | ||
851 | * is not very clear on the point. | ||
852 | */ | ||
853 | |||
854 | METHODDEF(boolean) | ||
855 | decode_mcu_DC_refine (j_decompress_ptr cinfo, JBLOCKROW *MCU_data) | ||
856 | { | ||
857 | huff_entropy_ptr entropy = (huff_entropy_ptr) cinfo->entropy; | ||
858 | int p1 = 1 << cinfo->Al; /* 1 in the bit position being coded */ | ||
859 | int blkn; | ||
860 | JBLOCKROW block; | ||
861 | BITREAD_STATE_VARS; | ||
862 | |||
863 | /* Process restart marker if needed; may have to suspend */ | ||
864 | if (cinfo->restart_interval) { | ||
865 | if (entropy->restarts_to_go == 0) | ||
866 | if (! process_restart(cinfo)) | ||
867 | return FALSE; | ||
868 | } | ||
869 | |||
870 | /* Not worth the cycles to check insufficient_data here, | ||
871 | * since we will not change the data anyway if we read zeroes. | ||
872 | */ | ||
873 | |||
874 | /* Load up working state */ | ||
875 | BITREAD_LOAD_STATE(cinfo,entropy->bitstate); | ||
876 | |||
877 | /* Outer loop handles each block in the MCU */ | ||
878 | |||
879 | for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) { | ||
880 | block = MCU_data[blkn]; | ||
881 | |||
882 | /* Encoded data is simply the next bit of the two's-complement DC value */ | ||
883 | CHECK_BIT_BUFFER(br_state, 1, return FALSE); | ||
884 | if (GET_BITS(1)) | ||
885 | (*block)[0] |= p1; | ||
886 | /* Note: since we use |=, repeating the assignment later is safe */ | ||
887 | } | ||
888 | |||
889 | /* Completed MCU, so update state */ | ||
890 | BITREAD_SAVE_STATE(cinfo,entropy->bitstate); | ||
891 | |||
892 | /* Account for restart interval (no-op if not using restarts) */ | ||
893 | entropy->restarts_to_go--; | ||
894 | |||
895 | return TRUE; | ||
896 | } | ||
897 | |||
898 | |||
899 | /* | ||
900 | * MCU decoding for AC successive approximation refinement scan. | ||
901 | */ | ||
902 | |||
903 | METHODDEF(boolean) | ||
904 | decode_mcu_AC_refine (j_decompress_ptr cinfo, JBLOCKROW *MCU_data) | ||
905 | { | ||
906 | huff_entropy_ptr entropy = (huff_entropy_ptr) cinfo->entropy; | ||
907 | register int s, k, r; | ||
908 | unsigned int EOBRUN; | ||
909 | int Se, p1, m1; | ||
910 | const int * natural_order; | ||
911 | JBLOCKROW block; | ||
912 | JCOEFPTR thiscoef; | ||
913 | BITREAD_STATE_VARS; | ||
914 | d_derived_tbl * tbl; | ||
915 | int num_newnz; | ||
916 | int newnz_pos[DCTSIZE2]; | ||
917 | |||
918 | /* Process restart marker if needed; may have to suspend */ | ||
919 | if (cinfo->restart_interval) { | ||
920 | if (entropy->restarts_to_go == 0) | ||
921 | if (! process_restart(cinfo)) | ||
922 | return FALSE; | ||
923 | } | ||
924 | |||
925 | /* If we've run out of data, don't modify the MCU. | ||
926 | */ | ||
927 | if (! entropy->insufficient_data) { | ||
928 | |||
929 | Se = cinfo->Se; | ||
930 | p1 = 1 << cinfo->Al; /* 1 in the bit position being coded */ | ||
931 | m1 = (-1) << cinfo->Al; /* -1 in the bit position being coded */ | ||
932 | natural_order = cinfo->natural_order; | ||
933 | |||
934 | /* Load up working state */ | ||
935 | BITREAD_LOAD_STATE(cinfo,entropy->bitstate); | ||
936 | EOBRUN = entropy->saved.EOBRUN; /* only part of saved state we need */ | ||
937 | |||
938 | /* There is always only one block per MCU */ | ||
939 | block = MCU_data[0]; | ||
940 | tbl = entropy->ac_derived_tbl; | ||
941 | |||
942 | /* If we are forced to suspend, we must undo the assignments to any newly | ||
943 | * nonzero coefficients in the block, because otherwise we'd get confused | ||
944 | * next time about which coefficients were already nonzero. | ||
945 | * But we need not undo addition of bits to already-nonzero coefficients; | ||
946 | * instead, we can test the current bit to see if we already did it. | ||
947 | */ | ||
948 | num_newnz = 0; | ||
949 | |||
950 | /* initialize coefficient loop counter to start of band */ | ||
951 | k = cinfo->Ss; | ||
952 | |||
953 | if (EOBRUN == 0) { | ||
954 | for (; k <= Se; k++) { | ||
955 | HUFF_DECODE(s, br_state, tbl, goto undoit, label3); | ||
956 | r = s >> 4; | ||
957 | s &= 15; | ||
958 | if (s) { | ||
959 | if (s != 1) /* size of new coef should always be 1 */ | ||
960 | WARNMS(cinfo, JWRN_HUFF_BAD_CODE); | ||
961 | CHECK_BIT_BUFFER(br_state, 1, goto undoit); | ||
962 | if (GET_BITS(1)) | ||
963 | s = p1; /* newly nonzero coef is positive */ | ||
964 | else | ||
965 | s = m1; /* newly nonzero coef is negative */ | ||
966 | } else { | ||
967 | if (r != 15) { | ||
968 | EOBRUN = 1 << r; /* EOBr, run length is 2^r + appended bits */ | ||
969 | if (r) { | ||
970 | CHECK_BIT_BUFFER(br_state, r, goto undoit); | ||
971 | r = GET_BITS(r); | ||
972 | EOBRUN += r; | ||
973 | } | ||
974 | break; /* rest of block is handled by EOB logic */ | ||
975 | } | ||
976 | /* note s = 0 for processing ZRL */ | ||
977 | } | ||
978 | /* Advance over already-nonzero coefs and r still-zero coefs, | ||
979 | * appending correction bits to the nonzeroes. A correction bit is 1 | ||
980 | * if the absolute value of the coefficient must be increased. | ||
981 | */ | ||
982 | do { | ||
983 | thiscoef = *block + natural_order[k]; | ||
984 | if (*thiscoef != 0) { | ||
985 | CHECK_BIT_BUFFER(br_state, 1, goto undoit); | ||
986 | if (GET_BITS(1)) { | ||
987 | if ((*thiscoef & p1) == 0) { /* do nothing if already set it */ | ||
988 | if (*thiscoef >= 0) | ||
989 | *thiscoef += p1; | ||
990 | else | ||
991 | *thiscoef += m1; | ||
992 | } | ||
993 | } | ||
994 | } else { | ||
995 | if (--r < 0) | ||
996 | break; /* reached target zero coefficient */ | ||
997 | } | ||
998 | k++; | ||
999 | } while (k <= Se); | ||
1000 | if (s) { | ||
1001 | int pos = natural_order[k]; | ||
1002 | /* Output newly nonzero coefficient */ | ||
1003 | (*block)[pos] = (JCOEF) s; | ||
1004 | /* Remember its position in case we have to suspend */ | ||
1005 | newnz_pos[num_newnz++] = pos; | ||
1006 | } | ||
1007 | } | ||
1008 | } | ||
1009 | |||
1010 | if (EOBRUN > 0) { | ||
1011 | /* Scan any remaining coefficient positions after the end-of-band | ||
1012 | * (the last newly nonzero coefficient, if any). Append a correction | ||
1013 | * bit to each already-nonzero coefficient. A correction bit is 1 | ||
1014 | * if the absolute value of the coefficient must be increased. | ||
1015 | */ | ||
1016 | for (; k <= Se; k++) { | ||
1017 | thiscoef = *block + natural_order[k]; | ||
1018 | if (*thiscoef != 0) { | ||
1019 | CHECK_BIT_BUFFER(br_state, 1, goto undoit); | ||
1020 | if (GET_BITS(1)) { | ||
1021 | if ((*thiscoef & p1) == 0) { /* do nothing if already changed it */ | ||
1022 | if (*thiscoef >= 0) | ||
1023 | *thiscoef += p1; | ||
1024 | else | ||
1025 | *thiscoef += m1; | ||
1026 | } | ||
1027 | } | ||
1028 | } | ||
1029 | } | ||
1030 | /* Count one block completed in EOB run */ | ||
1031 | EOBRUN--; | ||
1032 | } | ||
1033 | |||
1034 | /* Completed MCU, so update state */ | ||
1035 | BITREAD_SAVE_STATE(cinfo,entropy->bitstate); | ||
1036 | entropy->saved.EOBRUN = EOBRUN; /* only part of saved state we need */ | ||
1037 | } | ||
1038 | |||
1039 | /* Account for restart interval (no-op if not using restarts) */ | ||
1040 | entropy->restarts_to_go--; | ||
1041 | |||
1042 | return TRUE; | ||
1043 | |||
1044 | undoit: | ||
1045 | /* Re-zero any output coefficients that we made newly nonzero */ | ||
1046 | while (num_newnz > 0) | ||
1047 | (*block)[newnz_pos[--num_newnz]] = 0; | ||
1048 | |||
1049 | return FALSE; | ||
1050 | } | ||
1051 | |||
1052 | |||
1053 | /* | ||
1054 | * Decode one MCU's worth of Huffman-compressed coefficients, | ||
1055 | * partial blocks. | ||
1056 | */ | ||
1057 | |||
1058 | METHODDEF(boolean) | ||
1059 | decode_mcu_sub (j_decompress_ptr cinfo, JBLOCKROW *MCU_data) | ||
1060 | { | ||
1061 | huff_entropy_ptr entropy = (huff_entropy_ptr) cinfo->entropy; | ||
1062 | const int * natural_order; | ||
1063 | int Se, blkn; | ||
1064 | BITREAD_STATE_VARS; | ||
1065 | savable_state state; | ||
1066 | |||
1067 | /* Process restart marker if needed; may have to suspend */ | ||
1068 | if (cinfo->restart_interval) { | ||
1069 | if (entropy->restarts_to_go == 0) | ||
1070 | if (! process_restart(cinfo)) | ||
1071 | return FALSE; | ||
1072 | } | ||
1073 | |||
1074 | /* If we've run out of data, just leave the MCU set to zeroes. | ||
1075 | * This way, we return uniform gray for the remainder of the segment. | ||
1076 | */ | ||
1077 | if (! entropy->insufficient_data) { | ||
1078 | |||
1079 | natural_order = cinfo->natural_order; | ||
1080 | Se = cinfo->lim_Se; | ||
1081 | |||
1082 | /* Load up working state */ | ||
1083 | BITREAD_LOAD_STATE(cinfo,entropy->bitstate); | ||
1084 | ASSIGN_STATE(state, entropy->saved); | ||
1085 | |||
1086 | /* Outer loop handles each block in the MCU */ | ||
1087 | |||
1088 | for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) { | ||
1089 | JBLOCKROW block = MCU_data[blkn]; | ||
1090 | d_derived_tbl * htbl; | ||
1091 | register int s, k, r; | ||
1092 | int coef_limit, ci; | ||
1093 | |||
1094 | /* Decode a single block's worth of coefficients */ | ||
1095 | |||
1096 | /* Section F.2.2.1: decode the DC coefficient difference */ | ||
1097 | htbl = entropy->dc_cur_tbls[blkn]; | ||
1098 | HUFF_DECODE(s, br_state, htbl, return FALSE, label1); | ||
1099 | |||
1100 | htbl = entropy->ac_cur_tbls[blkn]; | ||
1101 | k = 1; | ||
1102 | coef_limit = entropy->coef_limit[blkn]; | ||
1103 | if (coef_limit) { | ||
1104 | /* Convert DC difference to actual value, update last_dc_val */ | ||
1105 | if (s) { | ||
1106 | CHECK_BIT_BUFFER(br_state, s, return FALSE); | ||
1107 | r = GET_BITS(s); | ||
1108 | s = HUFF_EXTEND(r, s); | ||
1109 | } | ||
1110 | ci = cinfo->MCU_membership[blkn]; | ||
1111 | s += state.last_dc_val[ci]; | ||
1112 | state.last_dc_val[ci] = s; | ||
1113 | /* Output the DC coefficient */ | ||
1114 | (*block)[0] = (JCOEF) s; | ||
1115 | |||
1116 | /* Section F.2.2.2: decode the AC coefficients */ | ||
1117 | /* Since zeroes are skipped, output area must be cleared beforehand */ | ||
1118 | for (; k < coef_limit; k++) { | ||
1119 | HUFF_DECODE(s, br_state, htbl, return FALSE, label2); | ||
1120 | |||
1121 | r = s >> 4; | ||
1122 | s &= 15; | ||
1123 | |||
1124 | if (s) { | ||
1125 | k += r; | ||
1126 | CHECK_BIT_BUFFER(br_state, s, return FALSE); | ||
1127 | r = GET_BITS(s); | ||
1128 | s = HUFF_EXTEND(r, s); | ||
1129 | /* Output coefficient in natural (dezigzagged) order. | ||
1130 | * Note: the extra entries in natural_order[] will save us | ||
1131 | * if k > Se, which could happen if the data is corrupted. | ||
1132 | */ | ||
1133 | (*block)[natural_order[k]] = (JCOEF) s; | ||
1134 | } else { | ||
1135 | if (r != 15) | ||
1136 | goto EndOfBlock; | ||
1137 | k += 15; | ||
1138 | } | ||
1139 | } | ||
1140 | } else { | ||
1141 | if (s) { | ||
1142 | CHECK_BIT_BUFFER(br_state, s, return FALSE); | ||
1143 | DROP_BITS(s); | ||
1144 | } | ||
1145 | } | ||
1146 | |||
1147 | /* Section F.2.2.2: decode the AC coefficients */ | ||
1148 | /* In this path we just discard the values */ | ||
1149 | for (; k <= Se; k++) { | ||
1150 | HUFF_DECODE(s, br_state, htbl, return FALSE, label3); | ||
1151 | |||
1152 | r = s >> 4; | ||
1153 | s &= 15; | ||
1154 | |||
1155 | if (s) { | ||
1156 | k += r; | ||
1157 | CHECK_BIT_BUFFER(br_state, s, return FALSE); | ||
1158 | DROP_BITS(s); | ||
1159 | } else { | ||
1160 | if (r != 15) | ||
1161 | break; | ||
1162 | k += 15; | ||
1163 | } | ||
1164 | } | ||
1165 | |||
1166 | EndOfBlock: ; | ||
1167 | } | ||
1168 | |||
1169 | /* Completed MCU, so update state */ | ||
1170 | BITREAD_SAVE_STATE(cinfo,entropy->bitstate); | ||
1171 | ASSIGN_STATE(entropy->saved, state); | ||
1172 | } | ||
1173 | |||
1174 | /* Account for restart interval (no-op if not using restarts) */ | ||
1175 | entropy->restarts_to_go--; | ||
1176 | |||
1177 | return TRUE; | ||
1178 | } | ||
1179 | |||
1180 | |||
1181 | /* | ||
1182 | * Decode one MCU's worth of Huffman-compressed coefficients, | ||
1183 | * full-size blocks. | ||
1184 | */ | ||
1185 | |||
1186 | METHODDEF(boolean) | ||
1187 | decode_mcu (j_decompress_ptr cinfo, JBLOCKROW *MCU_data) | ||
1188 | { | ||
1189 | huff_entropy_ptr entropy = (huff_entropy_ptr) cinfo->entropy; | ||
1190 | int blkn; | ||
1191 | BITREAD_STATE_VARS; | ||
1192 | savable_state state; | ||
1193 | |||
1194 | /* Process restart marker if needed; may have to suspend */ | ||
1195 | if (cinfo->restart_interval) { | ||
1196 | if (entropy->restarts_to_go == 0) | ||
1197 | if (! process_restart(cinfo)) | ||
1198 | return FALSE; | ||
1199 | } | ||
1200 | |||
1201 | /* If we've run out of data, just leave the MCU set to zeroes. | ||
1202 | * This way, we return uniform gray for the remainder of the segment. | ||
1203 | */ | ||
1204 | if (! entropy->insufficient_data) { | ||
1205 | |||
1206 | /* Load up working state */ | ||
1207 | BITREAD_LOAD_STATE(cinfo,entropy->bitstate); | ||
1208 | ASSIGN_STATE(state, entropy->saved); | ||
1209 | |||
1210 | /* Outer loop handles each block in the MCU */ | ||
1211 | |||
1212 | for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) { | ||
1213 | JBLOCKROW block = MCU_data[blkn]; | ||
1214 | d_derived_tbl * htbl; | ||
1215 | register int s, k, r; | ||
1216 | int coef_limit, ci; | ||
1217 | |||
1218 | /* Decode a single block's worth of coefficients */ | ||
1219 | |||
1220 | /* Section F.2.2.1: decode the DC coefficient difference */ | ||
1221 | htbl = entropy->dc_cur_tbls[blkn]; | ||
1222 | HUFF_DECODE(s, br_state, htbl, return FALSE, label1); | ||
1223 | |||
1224 | htbl = entropy->ac_cur_tbls[blkn]; | ||
1225 | k = 1; | ||
1226 | coef_limit = entropy->coef_limit[blkn]; | ||
1227 | if (coef_limit) { | ||
1228 | /* Convert DC difference to actual value, update last_dc_val */ | ||
1229 | if (s) { | ||
1230 | CHECK_BIT_BUFFER(br_state, s, return FALSE); | ||
1231 | r = GET_BITS(s); | ||
1232 | s = HUFF_EXTEND(r, s); | ||
1233 | } | ||
1234 | ci = cinfo->MCU_membership[blkn]; | ||
1235 | s += state.last_dc_val[ci]; | ||
1236 | state.last_dc_val[ci] = s; | ||
1237 | /* Output the DC coefficient */ | ||
1238 | (*block)[0] = (JCOEF) s; | ||
1239 | |||
1240 | /* Section F.2.2.2: decode the AC coefficients */ | ||
1241 | /* Since zeroes are skipped, output area must be cleared beforehand */ | ||
1242 | for (; k < coef_limit; k++) { | ||
1243 | HUFF_DECODE(s, br_state, htbl, return FALSE, label2); | ||
1244 | |||
1245 | r = s >> 4; | ||
1246 | s &= 15; | ||
1247 | |||
1248 | if (s) { | ||
1249 | k += r; | ||
1250 | CHECK_BIT_BUFFER(br_state, s, return FALSE); | ||
1251 | r = GET_BITS(s); | ||
1252 | s = HUFF_EXTEND(r, s); | ||
1253 | /* Output coefficient in natural (dezigzagged) order. | ||
1254 | * Note: the extra entries in jpeg_natural_order[] will save us | ||
1255 | * if k >= DCTSIZE2, which could happen if the data is corrupted. | ||
1256 | */ | ||
1257 | (*block)[jpeg_natural_order[k]] = (JCOEF) s; | ||
1258 | } else { | ||
1259 | if (r != 15) | ||
1260 | goto EndOfBlock; | ||
1261 | k += 15; | ||
1262 | } | ||
1263 | } | ||
1264 | } else { | ||
1265 | if (s) { | ||
1266 | CHECK_BIT_BUFFER(br_state, s, return FALSE); | ||
1267 | DROP_BITS(s); | ||
1268 | } | ||
1269 | } | ||
1270 | |||
1271 | /* Section F.2.2.2: decode the AC coefficients */ | ||
1272 | /* In this path we just discard the values */ | ||
1273 | for (; k < DCTSIZE2; k++) { | ||
1274 | HUFF_DECODE(s, br_state, htbl, return FALSE, label3); | ||
1275 | |||
1276 | r = s >> 4; | ||
1277 | s &= 15; | ||
1278 | |||
1279 | if (s) { | ||
1280 | k += r; | ||
1281 | CHECK_BIT_BUFFER(br_state, s, return FALSE); | ||
1282 | DROP_BITS(s); | ||
1283 | } else { | ||
1284 | if (r != 15) | ||
1285 | break; | ||
1286 | k += 15; | ||
1287 | } | ||
1288 | } | ||
1289 | |||
1290 | EndOfBlock: ; | ||
1291 | } | ||
1292 | |||
1293 | /* Completed MCU, so update state */ | ||
1294 | BITREAD_SAVE_STATE(cinfo,entropy->bitstate); | ||
1295 | ASSIGN_STATE(entropy->saved, state); | ||
1296 | } | ||
1297 | |||
1298 | /* Account for restart interval (no-op if not using restarts) */ | ||
1299 | entropy->restarts_to_go--; | ||
1300 | |||
1301 | return TRUE; | ||
1302 | } | ||
1303 | |||
1304 | |||
1305 | /* | ||
1306 | * Initialize for a Huffman-compressed scan. | ||
1307 | */ | ||
1308 | |||
1309 | METHODDEF(void) | ||
1310 | start_pass_huff_decoder (j_decompress_ptr cinfo) | ||
1311 | { | ||
1312 | huff_entropy_ptr entropy = (huff_entropy_ptr) cinfo->entropy; | ||
1313 | int ci, blkn, tbl, i; | ||
1314 | jpeg_component_info * compptr; | ||
1315 | |||
1316 | if (cinfo->progressive_mode) { | ||
1317 | /* Validate progressive scan parameters */ | ||
1318 | if (cinfo->Ss == 0) { | ||
1319 | if (cinfo->Se != 0) | ||
1320 | goto bad; | ||
1321 | } else { | ||
1322 | /* need not check Ss/Se < 0 since they came from unsigned bytes */ | ||
1323 | if (cinfo->Se < cinfo->Ss || cinfo->Se > cinfo->lim_Se) | ||
1324 | goto bad; | ||
1325 | /* AC scans may have only one component */ | ||
1326 | if (cinfo->comps_in_scan != 1) | ||
1327 | goto bad; | ||
1328 | } | ||
1329 | if (cinfo->Ah != 0) { | ||
1330 | /* Successive approximation refinement scan: must have Al = Ah-1. */ | ||
1331 | if (cinfo->Ah-1 != cinfo->Al) | ||
1332 | goto bad; | ||
1333 | } | ||
1334 | if (cinfo->Al > 13) { /* need not check for < 0 */ | ||
1335 | /* Arguably the maximum Al value should be less than 13 for 8-bit precision, | ||
1336 | * but the spec doesn't say so, and we try to be liberal about what we | ||
1337 | * accept. Note: large Al values could result in out-of-range DC | ||
1338 | * coefficients during early scans, leading to bizarre displays due to | ||
1339 | * overflows in the IDCT math. But we won't crash. | ||
1340 | */ | ||
1341 | bad: | ||
1342 | ERREXIT4(cinfo, JERR_BAD_PROGRESSION, | ||
1343 | cinfo->Ss, cinfo->Se, cinfo->Ah, cinfo->Al); | ||
1344 | } | ||
1345 | /* Update progression status, and verify that scan order is legal. | ||
1346 | * Note that inter-scan inconsistencies are treated as warnings | ||
1347 | * not fatal errors ... not clear if this is right way to behave. | ||
1348 | */ | ||
1349 | for (ci = 0; ci < cinfo->comps_in_scan; ci++) { | ||
1350 | int coefi, cindex = cinfo->cur_comp_info[ci]->component_index; | ||
1351 | int *coef_bit_ptr = & cinfo->coef_bits[cindex][0]; | ||
1352 | if (cinfo->Ss && coef_bit_ptr[0] < 0) /* AC without prior DC scan */ | ||
1353 | WARNMS2(cinfo, JWRN_BOGUS_PROGRESSION, cindex, 0); | ||
1354 | for (coefi = cinfo->Ss; coefi <= cinfo->Se; coefi++) { | ||
1355 | int expected = (coef_bit_ptr[coefi] < 0) ? 0 : coef_bit_ptr[coefi]; | ||
1356 | if (cinfo->Ah != expected) | ||
1357 | WARNMS2(cinfo, JWRN_BOGUS_PROGRESSION, cindex, coefi); | ||
1358 | coef_bit_ptr[coefi] = cinfo->Al; | ||
1359 | } | ||
1360 | } | ||
1361 | |||
1362 | /* Select MCU decoding routine */ | ||
1363 | if (cinfo->Ah == 0) { | ||
1364 | if (cinfo->Ss == 0) | ||
1365 | entropy->pub.decode_mcu = decode_mcu_DC_first; | ||
1366 | else | ||
1367 | entropy->pub.decode_mcu = decode_mcu_AC_first; | ||
1368 | } else { | ||
1369 | if (cinfo->Ss == 0) | ||
1370 | entropy->pub.decode_mcu = decode_mcu_DC_refine; | ||
1371 | else | ||
1372 | entropy->pub.decode_mcu = decode_mcu_AC_refine; | ||
1373 | } | ||
1374 | |||
1375 | for (ci = 0; ci < cinfo->comps_in_scan; ci++) { | ||
1376 | compptr = cinfo->cur_comp_info[ci]; | ||
1377 | /* Make sure requested tables are present, and compute derived tables. | ||
1378 | * We may build same derived table more than once, but it's not expensive. | ||
1379 | */ | ||
1380 | if (cinfo->Ss == 0) { | ||
1381 | if (cinfo->Ah == 0) { /* DC refinement needs no table */ | ||
1382 | tbl = compptr->dc_tbl_no; | ||
1383 | jpeg_make_d_derived_tbl(cinfo, TRUE, tbl, | ||
1384 | & entropy->derived_tbls[tbl]); | ||
1385 | } | ||
1386 | } else { | ||
1387 | tbl = compptr->ac_tbl_no; | ||
1388 | jpeg_make_d_derived_tbl(cinfo, FALSE, tbl, | ||
1389 | & entropy->derived_tbls[tbl]); | ||
1390 | /* remember the single active table */ | ||
1391 | entropy->ac_derived_tbl = entropy->derived_tbls[tbl]; | ||
1392 | } | ||
1393 | /* Initialize DC predictions to 0 */ | ||
1394 | entropy->saved.last_dc_val[ci] = 0; | ||
1395 | } | ||
1396 | |||
1397 | /* Initialize private state variables */ | ||
1398 | entropy->saved.EOBRUN = 0; | ||
1399 | } else { | ||
1400 | /* Check that the scan parameters Ss, Se, Ah/Al are OK for sequential JPEG. | ||
1401 | * This ought to be an error condition, but we make it a warning because | ||
1402 | * there are some baseline files out there with all zeroes in these bytes. | ||
1403 | */ | ||
1404 | if (cinfo->Ss != 0 || cinfo->Ah != 0 || cinfo->Al != 0 || | ||
1405 | ((cinfo->is_baseline || cinfo->Se < DCTSIZE2) && | ||
1406 | cinfo->Se != cinfo->lim_Se)) | ||
1407 | WARNMS(cinfo, JWRN_NOT_SEQUENTIAL); | ||
1408 | |||
1409 | /* Select MCU decoding routine */ | ||
1410 | /* We retain the hard-coded case for full-size blocks. | ||
1411 | * This is not necessary, but it appears that this version is slightly | ||
1412 | * more performant in the given implementation. | ||
1413 | * With an improved implementation we would prefer a single optimized | ||
1414 | * function. | ||
1415 | */ | ||
1416 | if (cinfo->lim_Se != DCTSIZE2-1) | ||
1417 | entropy->pub.decode_mcu = decode_mcu_sub; | ||
1418 | else | ||
1419 | entropy->pub.decode_mcu = decode_mcu; | ||
1420 | |||
1421 | for (ci = 0; ci < cinfo->comps_in_scan; ci++) { | ||
1422 | compptr = cinfo->cur_comp_info[ci]; | ||
1423 | /* Compute derived values for Huffman tables */ | ||
1424 | /* We may do this more than once for a table, but it's not expensive */ | ||
1425 | tbl = compptr->dc_tbl_no; | ||
1426 | jpeg_make_d_derived_tbl(cinfo, TRUE, tbl, | ||
1427 | & entropy->dc_derived_tbls[tbl]); | ||
1428 | if (cinfo->lim_Se) { /* AC needs no table when not present */ | ||
1429 | tbl = compptr->ac_tbl_no; | ||
1430 | jpeg_make_d_derived_tbl(cinfo, FALSE, tbl, | ||
1431 | & entropy->ac_derived_tbls[tbl]); | ||
1432 | } | ||
1433 | /* Initialize DC predictions to 0 */ | ||
1434 | entropy->saved.last_dc_val[ci] = 0; | ||
1435 | } | ||
1436 | |||
1437 | /* Precalculate decoding info for each block in an MCU of this scan */ | ||
1438 | for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) { | ||
1439 | ci = cinfo->MCU_membership[blkn]; | ||
1440 | compptr = cinfo->cur_comp_info[ci]; | ||
1441 | /* Precalculate which table to use for each block */ | ||
1442 | entropy->dc_cur_tbls[blkn] = entropy->dc_derived_tbls[compptr->dc_tbl_no]; | ||
1443 | entropy->ac_cur_tbls[blkn] = entropy->ac_derived_tbls[compptr->ac_tbl_no]; | ||
1444 | /* Decide whether we really care about the coefficient values */ | ||
1445 | if (compptr->component_needed) { | ||
1446 | ci = compptr->DCT_v_scaled_size; | ||
1447 | i = compptr->DCT_h_scaled_size; | ||
1448 | switch (cinfo->lim_Se) { | ||
1449 | case (1*1-1): | ||
1450 | entropy->coef_limit[blkn] = 1; | ||
1451 | break; | ||
1452 | case (2*2-1): | ||
1453 | if (ci <= 0 || ci > 2) ci = 2; | ||
1454 | if (i <= 0 || i > 2) i = 2; | ||
1455 | entropy->coef_limit[blkn] = 1 + jpeg_zigzag_order2[ci - 1][i - 1]; | ||
1456 | break; | ||
1457 | case (3*3-1): | ||
1458 | if (ci <= 0 || ci > 3) ci = 3; | ||
1459 | if (i <= 0 || i > 3) i = 3; | ||
1460 | entropy->coef_limit[blkn] = 1 + jpeg_zigzag_order3[ci - 1][i - 1]; | ||
1461 | break; | ||
1462 | case (4*4-1): | ||
1463 | if (ci <= 0 || ci > 4) ci = 4; | ||
1464 | if (i <= 0 || i > 4) i = 4; | ||
1465 | entropy->coef_limit[blkn] = 1 + jpeg_zigzag_order4[ci - 1][i - 1]; | ||
1466 | break; | ||
1467 | case (5*5-1): | ||
1468 | if (ci <= 0 || ci > 5) ci = 5; | ||
1469 | if (i <= 0 || i > 5) i = 5; | ||
1470 | entropy->coef_limit[blkn] = 1 + jpeg_zigzag_order5[ci - 1][i - 1]; | ||
1471 | break; | ||
1472 | case (6*6-1): | ||
1473 | if (ci <= 0 || ci > 6) ci = 6; | ||
1474 | if (i <= 0 || i > 6) i = 6; | ||
1475 | entropy->coef_limit[blkn] = 1 + jpeg_zigzag_order6[ci - 1][i - 1]; | ||
1476 | break; | ||
1477 | case (7*7-1): | ||
1478 | if (ci <= 0 || ci > 7) ci = 7; | ||
1479 | if (i <= 0 || i > 7) i = 7; | ||
1480 | entropy->coef_limit[blkn] = 1 + jpeg_zigzag_order7[ci - 1][i - 1]; | ||
1481 | break; | ||
1482 | default: | ||
1483 | if (ci <= 0 || ci > 8) ci = 8; | ||
1484 | if (i <= 0 || i > 8) i = 8; | ||
1485 | entropy->coef_limit[blkn] = 1 + jpeg_zigzag_order[ci - 1][i - 1]; | ||
1486 | break; | ||
1487 | } | ||
1488 | } else { | ||
1489 | entropy->coef_limit[blkn] = 0; | ||
1490 | } | ||
1491 | } | ||
1492 | } | ||
1493 | |||
1494 | /* Initialize bitread state variables */ | ||
1495 | entropy->bitstate.bits_left = 0; | ||
1496 | entropy->bitstate.get_buffer = 0; /* unnecessary, but keeps Purify quiet */ | ||
1497 | entropy->insufficient_data = FALSE; | ||
1498 | |||
1499 | /* Initialize restart counter */ | ||
1500 | entropy->restarts_to_go = cinfo->restart_interval; | ||
1501 | } | ||
1502 | |||
1503 | |||
1504 | /* | ||
1505 | * Module initialization routine for Huffman entropy decoding. | ||
1506 | */ | ||
1507 | |||
1508 | GLOBAL(void) | ||
1509 | jinit_huff_decoder (j_decompress_ptr cinfo) | ||
1510 | { | ||
1511 | huff_entropy_ptr entropy; | ||
1512 | int i; | ||
1513 | |||
1514 | entropy = (huff_entropy_ptr) | ||
1515 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, | ||
1516 | SIZEOF(huff_entropy_decoder)); | ||
1517 | cinfo->entropy = (struct jpeg_entropy_decoder *) entropy; | ||
1518 | entropy->pub.start_pass = start_pass_huff_decoder; | ||
1519 | |||
1520 | if (cinfo->progressive_mode) { | ||
1521 | /* Create progression status table */ | ||
1522 | int *coef_bit_ptr, ci; | ||
1523 | cinfo->coef_bits = (int (*)[DCTSIZE2]) | ||
1524 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, | ||
1525 | cinfo->num_components*DCTSIZE2*SIZEOF(int)); | ||
1526 | coef_bit_ptr = & cinfo->coef_bits[0][0]; | ||
1527 | for (ci = 0; ci < cinfo->num_components; ci++) | ||
1528 | for (i = 0; i < DCTSIZE2; i++) | ||
1529 | *coef_bit_ptr++ = -1; | ||
1530 | |||
1531 | /* Mark derived tables unallocated */ | ||
1532 | for (i = 0; i < NUM_HUFF_TBLS; i++) { | ||
1533 | entropy->derived_tbls[i] = NULL; | ||
1534 | } | ||
1535 | } else { | ||
1536 | /* Mark tables unallocated */ | ||
1537 | for (i = 0; i < NUM_HUFF_TBLS; i++) { | ||
1538 | entropy->dc_derived_tbls[i] = entropy->ac_derived_tbls[i] = NULL; | ||
1539 | } | ||
1540 | } | ||
1541 | } | ||