Remove damned ancient DOS line endings from Irrlicht. Hopefully I did not go overboard.

1 files changed, 857 insertions, 857 deletions

diff --git a/libraries/irrlicht-1.8/source/Irrlicht/jpeglib/jquant1.c b/libraries/irrlicht-1.8/source/Irrlicht/jpeglib/jquant1.c
index 1c482bc..9d11f70 100644
--- a/libraries/irrlicht-1.8/source/Irrlicht/jpeglib/jquant1.c
+++ b/libraries/irrlicht-1.8/source/Irrlicht/jpeglib/jquant1.c
@@ -1,857 +1,857 @@
-/*

- * jquant1.c

- *

- * Copyright (C) 1991-1996, Thomas G. Lane.

- * Modified 2011 by Guido Vollbeding.

- * This file is part of the Independent JPEG Group's software.

- * For conditions of distribution and use, see the accompanying README file.

- *

- * This file contains 1-pass color quantization (color mapping) routines.

- * These routines provide mapping to a fixed color map using equally spaced

- * color values.  Optional Floyd-Steinberg or ordered dithering is available.

- */

-

-#define JPEG_INTERNALS

-#include "jinclude.h"

-#include "jpeglib.h"

-

-#ifdef QUANT_1PASS_SUPPORTED

-

-

-/*

- * The main purpose of 1-pass quantization is to provide a fast, if not very

- * high quality, colormapped output capability.  A 2-pass quantizer usually

- * gives better visual quality; however, for quantized grayscale output this

- * quantizer is perfectly adequate.  Dithering is highly recommended with this

- * quantizer, though you can turn it off if you really want to.

- *

- * In 1-pass quantization the colormap must be chosen in advance of seeing the

- * image.  We use a map consisting of all combinations of Ncolors[i] color

- * values for the i'th component.  The Ncolors[] values are chosen so that

- * their product, the total number of colors, is no more than that requested.

- * (In most cases, the product will be somewhat less.)

- *

- * Since the colormap is orthogonal, the representative value for each color

- * component can be determined without considering the other components;

- * then these indexes can be combined into a colormap index by a standard

- * N-dimensional-array-subscript calculation.  Most of the arithmetic involved

- * can be precalculated and stored in the lookup table colorindex[].

- * colorindex[i][j] maps pixel value j in component i to the nearest

- * representative value (grid plane) for that component; this index is

- * multiplied by the array stride for component i, so that the

- * index of the colormap entry closest to a given pixel value is just

- *    sum( colorindex[component-number][pixel-component-value] )

- * Aside from being fast, this scheme allows for variable spacing between

- * representative values with no additional lookup cost.

- *

- * If gamma correction has been applied in color conversion, it might be wise

- * to adjust the color grid spacing so that the representative colors are

- * equidistant in linear space.  At this writing, gamma correction is not

- * implemented by jdcolor, so nothing is done here.

- */

-

-

-/* Declarations for ordered dithering.

- *

- * We use a standard 16x16 ordered dither array.  The basic concept of ordered

- * dithering is described in many references, for instance Dale Schumacher's

- * chapter II.2 of Graphics Gems II (James Arvo, ed. Academic Press, 1991).

- * In place of Schumacher's comparisons against a "threshold" value, we add a

- * "dither" value to the input pixel and then round the result to the nearest

- * output value.  The dither value is equivalent to (0.5 - threshold) times

- * the distance between output values.  For ordered dithering, we assume that

- * the output colors are equally spaced; if not, results will probably be

- * worse, since the dither may be too much or too little at a given point.

- *

- * The normal calculation would be to form pixel value + dither, range-limit

- * this to 0..MAXJSAMPLE, and then index into the colorindex table as usual.

- * We can skip the separate range-limiting step by extending the colorindex

- * table in both directions.

- */

-

-#define ODITHER_SIZE  16        /* dimension of dither matrix */

-/* NB: if ODITHER_SIZE is not a power of 2, ODITHER_MASK uses will break */

-#define ODITHER_CELLS (ODITHER_SIZE*ODITHER_SIZE)       /* # cells in matrix */

-#define ODITHER_MASK  (ODITHER_SIZE-1) /* mask for wrapping around counters */

-

-typedef int ODITHER_MATRIX[ODITHER_SIZE][ODITHER_SIZE];

-typedef int (*ODITHER_MATRIX_PTR)[ODITHER_SIZE];

-

-static const UINT8 base_dither_matrix[ODITHER_SIZE][ODITHER_SIZE] = {

-  /* Bayer's order-4 dither array.  Generated by the code given in

-   * Stephen Hawley's article "Ordered Dithering" in Graphics Gems I.

-   * The values in this array must range from 0 to ODITHER_CELLS-1.

-   */

-  {   0,192, 48,240, 12,204, 60,252,  3,195, 51,243, 15,207, 63,255 },

-  { 128, 64,176,112,140, 76,188,124,131, 67,179,115,143, 79,191,127 },

-  {  32,224, 16,208, 44,236, 28,220, 35,227, 19,211, 47,239, 31,223 },

-  { 160, 96,144, 80,172,108,156, 92,163, 99,147, 83,175,111,159, 95 },

-  {   8,200, 56,248,  4,196, 52,244, 11,203, 59,251,  7,199, 55,247 },

-  { 136, 72,184,120,132, 68,180,116,139, 75,187,123,135, 71,183,119 },

-  {  40,232, 24,216, 36,228, 20,212, 43,235, 27,219, 39,231, 23,215 },

-  { 168,104,152, 88,164,100,148, 84,171,107,155, 91,167,103,151, 87 },

-  {   2,194, 50,242, 14,206, 62,254,  1,193, 49,241, 13,205, 61,253 },

-  { 130, 66,178,114,142, 78,190,126,129, 65,177,113,141, 77,189,125 },

-  {  34,226, 18,210, 46,238, 30,222, 33,225, 17,209, 45,237, 29,221 },

-  { 162, 98,146, 82,174,110,158, 94,161, 97,145, 81,173,109,157, 93 },

-  {  10,202, 58,250,  6,198, 54,246,  9,201, 57,249,  5,197, 53,245 },

-  { 138, 74,186,122,134, 70,182,118,137, 73,185,121,133, 69,181,117 },

-  {  42,234, 26,218, 38,230, 22,214, 41,233, 25,217, 37,229, 21,213 },

-  { 170,106,154, 90,166,102,150, 86,169,105,153, 89,165,101,149, 85 }

-};

-

-

-/* Declarations for Floyd-Steinberg dithering.

- *

- * Errors are accumulated into the array fserrors[], at a resolution of

- * 1/16th of a pixel count.  The error at a given pixel is propagated

- * to its not-yet-processed neighbors using the standard F-S fractions,

- *              ...     (here)  7/16

- *              3/16    5/16    1/16

- * We work left-to-right on even rows, right-to-left on odd rows.

- *

- * We can get away with a single array (holding one row's worth of errors)

- * by using it to store the current row's errors at pixel columns not yet

- * processed, but the next row's errors at columns already processed.  We

- * need only a few extra variables to hold the errors immediately around the

- * current column.  (If we are lucky, those variables are in registers, but

- * even if not, they're probably cheaper to access than array elements are.)

- *

- * The fserrors[] array is indexed [component#][position].

- * We provide (#columns + 2) entries per component; the extra entry at each

- * end saves us from special-casing the first and last pixels.

- *

- * Note: on a wide image, we might not have enough room in a PC's near data

- * segment to hold the error array; so it is allocated with alloc_large.

- */

-

-#if BITS_IN_JSAMPLE == 8

-typedef INT16 FSERROR;          /* 16 bits should be enough */

-typedef int LOCFSERROR;         /* use 'int' for calculation temps */

-#else

-typedef INT32 FSERROR;          /* may need more than 16 bits */

-typedef INT32 LOCFSERROR;       /* be sure calculation temps are big enough */

-#endif

-

-typedef FSERROR FAR *FSERRPTR;  /* pointer to error array (in FAR storage!) */

-

-

-/* Private subobject */

-

-#define MAX_Q_COMPS 4           /* max components I can handle */

-

-typedef struct {

-  struct jpeg_color_quantizer pub; /* public fields */

-

-  /* Initially allocated colormap is saved here */

-  JSAMPARRAY sv_colormap;       /* The color map as a 2-D pixel array */

-  int sv_actual;                /* number of entries in use */

-

-  JSAMPARRAY colorindex;        /* Precomputed mapping for speed */

-  /* colorindex[i][j] = index of color closest to pixel value j in component i,

-   * premultiplied as described above.  Since colormap indexes must fit into

-   * JSAMPLEs, the entries of this array will too.

-   */

-  boolean is_padded;            /* is the colorindex padded for odither? */

-

-  int Ncolors[MAX_Q_COMPS];     /* # of values alloced to each component */

-

-  /* Variables for ordered dithering */

-  int row_index;                /* cur row's vertical index in dither matrix */

-  ODITHER_MATRIX_PTR odither[MAX_Q_COMPS]; /* one dither array per component */

-

-  /* Variables for Floyd-Steinberg dithering */

-  FSERRPTR fserrors[MAX_Q_COMPS]; /* accumulated errors */

-  boolean on_odd_row;           /* flag to remember which row we are on */

-} my_cquantizer;

-

-typedef my_cquantizer * my_cquantize_ptr;

-

-

-/*

- * Policy-making subroutines for create_colormap and create_colorindex.

- * These routines determine the colormap to be used.  The rest of the module

- * only assumes that the colormap is orthogonal.

- *

- *  * select_ncolors decides how to divvy up the available colors

- *    among the components.

- *  * output_value defines the set of representative values for a component.

- *  * largest_input_value defines the mapping from input values to

- *    representative values for a component.

- * Note that the latter two routines may impose different policies for

- * different components, though this is not currently done.

- */

-

-

-LOCAL(int)

-select_ncolors (j_decompress_ptr cinfo, int Ncolors[])

-/* Determine allocation of desired colors to components, */

-/* and fill in Ncolors[] array to indicate choice. */

-/* Return value is total number of colors (product of Ncolors[] values). */

-{

-  int nc = cinfo->out_color_components; /* number of color components */

-  int max_colors = cinfo->desired_number_of_colors;

-  int total_colors, iroot, i, j;

-  boolean changed;

-  long temp;

-  static const int RGB_order[3] = { RGB_GREEN, RGB_RED, RGB_BLUE };

-

-  /* We can allocate at least the nc'th root of max_colors per component. */

-  /* Compute floor(nc'th root of max_colors). */

-  iroot = 1;

-  do {

-    iroot++;

-    temp = iroot;               /* set temp = iroot ** nc */

-    for (i = 1; i < nc; i++)

-      temp *= iroot;

-  } while (temp <= (long) max_colors); /* repeat till iroot exceeds root */

-  iroot--;                      /* now iroot = floor(root) */

-

-  /* Must have at least 2 color values per component */

-  if (iroot < 2)

-    ERREXIT1(cinfo, JERR_QUANT_FEW_COLORS, (int) temp);

-

-  /* Initialize to iroot color values for each component */

-  total_colors = 1;

-  for (i = 0; i < nc; i++) {

-    Ncolors[i] = iroot;

-    total_colors *= iroot;

-  }

-  /* We may be able to increment the count for one or more components without

-   * exceeding max_colors, though we know not all can be incremented.

-   * Sometimes, the first component can be incremented more than once!

-   * (Example: for 16 colors, we start at 2*2*2, go to 3*2*2, then 4*2*2.)

-   * In RGB colorspace, try to increment G first, then R, then B.

-   */

-  do {

-    changed = FALSE;

-    for (i = 0; i < nc; i++) {

-      j = (cinfo->out_color_space == JCS_RGB ? RGB_order[i] : i);

-      /* calculate new total_colors if Ncolors[j] is incremented */

-      temp = total_colors / Ncolors[j];

-      temp *= Ncolors[j]+1;     /* done in long arith to avoid oflo */

-      if (temp > (long) max_colors)

-        break;                  /* won't fit, done with this pass */

-      Ncolors[j]++;             /* OK, apply the increment */

-      total_colors = (int) temp;

-      changed = TRUE;

-    }

-  } while (changed);

-

-  return total_colors;

-}

-

-

-LOCAL(int)

-output_value (j_decompress_ptr cinfo, int ci, int j, int maxj)

-/* Return j'th output value, where j will range from 0 to maxj */

-/* The output values must fall in 0..MAXJSAMPLE in increasing order */

-{

-  /* We always provide values 0 and MAXJSAMPLE for each component;

-   * any additional values are equally spaced between these limits.

-   * (Forcing the upper and lower values to the limits ensures that

-   * dithering can't produce a color outside the selected gamut.)

-   */

-  return (int) (((INT32) j * MAXJSAMPLE + maxj/2) / maxj);

-}

-

-

-LOCAL(int)

-largest_input_value (j_decompress_ptr cinfo, int ci, int j, int maxj)

-/* Return largest input value that should map to j'th output value */

-/* Must have largest(j=0) >= 0, and largest(j=maxj) >= MAXJSAMPLE */

-{

-  /* Breakpoints are halfway between values returned by output_value */

-  return (int) (((INT32) (2*j + 1) * MAXJSAMPLE + maxj) / (2*maxj));

-}

-

-

-/*

- * Create the colormap.

- */

-

-LOCAL(void)

-create_colormap (j_decompress_ptr cinfo)

-{

-  my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;

-  JSAMPARRAY colormap;          /* Created colormap */

-  int total_colors;             /* Number of distinct output colors */

-  int i,j,k, nci, blksize, blkdist, ptr, val;

-

-  /* Select number of colors for each component */

-  total_colors = select_ncolors(cinfo, cquantize->Ncolors);

-

-  /* Report selected color counts */

-  if (cinfo->out_color_components == 3)

-    TRACEMS4(cinfo, 1, JTRC_QUANT_3_NCOLORS,

-             total_colors, cquantize->Ncolors[0],

-             cquantize->Ncolors[1], cquantize->Ncolors[2]);

-  else

-    TRACEMS1(cinfo, 1, JTRC_QUANT_NCOLORS, total_colors);

-

-  /* Allocate and fill in the colormap. */

-  /* The colors are ordered in the map in standard row-major order, */

-  /* i.e. rightmost (highest-indexed) color changes most rapidly. */

-

-  colormap = (*cinfo->mem->alloc_sarray)

-    ((j_common_ptr) cinfo, JPOOL_IMAGE,

-     (JDIMENSION) total_colors, (JDIMENSION) cinfo->out_color_components);

-

-  /* blksize is number of adjacent repeated entries for a component */

-  /* blkdist is distance between groups of identical entries for a component */

-  blkdist = total_colors;

-

-  for (i = 0; i < cinfo->out_color_components; i++) {

-    /* fill in colormap entries for i'th color component */

-    nci = cquantize->Ncolors[i]; /* # of distinct values for this color */

-    blksize = blkdist / nci;

-    for (j = 0; j < nci; j++) {

-      /* Compute j'th output value (out of nci) for component */

-      val = output_value(cinfo, i, j, nci-1);

-      /* Fill in all colormap entries that have this value of this component */

-      for (ptr = j * blksize; ptr < total_colors; ptr += blkdist) {

-        /* fill in blksize entries beginning at ptr */

-        for (k = 0; k < blksize; k++)

-          colormap[i][ptr+k] = (JSAMPLE) val;

-      }

-    }

-    blkdist = blksize;          /* blksize of this color is blkdist of next */

-  }

-

-  /* Save the colormap in private storage,

-   * where it will survive color quantization mode changes.

-   */

-  cquantize->sv_colormap = colormap;

-  cquantize->sv_actual = total_colors;

-}

-

-

-/*

- * Create the color index table.

- */

-

-LOCAL(void)

-create_colorindex (j_decompress_ptr cinfo)

-{

-  my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;

-  JSAMPROW indexptr;

-  int i,j,k, nci, blksize, val, pad;

-

-  /* For ordered dither, we pad the color index tables by MAXJSAMPLE in

-   * each direction (input index values can be -MAXJSAMPLE .. 2*MAXJSAMPLE).

-   * This is not necessary in the other dithering modes.  However, we

-   * flag whether it was done in case user changes dithering mode.

-   */

-  if (cinfo->dither_mode == JDITHER_ORDERED) {

-    pad = MAXJSAMPLE*2;

-    cquantize->is_padded = TRUE;

-  } else {

-    pad = 0;

-    cquantize->is_padded = FALSE;

-  }

-

-  cquantize->colorindex = (*cinfo->mem->alloc_sarray)

-    ((j_common_ptr) cinfo, JPOOL_IMAGE,

-     (JDIMENSION) (MAXJSAMPLE+1 + pad),

-     (JDIMENSION) cinfo->out_color_components);

-

-  /* blksize is number of adjacent repeated entries for a component */

-  blksize = cquantize->sv_actual;

-

-  for (i = 0; i < cinfo->out_color_components; i++) {

-    /* fill in colorindex entries for i'th color component */

-    nci = cquantize->Ncolors[i]; /* # of distinct values for this color */

-    blksize = blksize / nci;

-

-    /* adjust colorindex pointers to provide padding at negative indexes. */

-    if (pad)

-      cquantize->colorindex[i] += MAXJSAMPLE;

-

-    /* in loop, val = index of current output value, */

-    /* and k = largest j that maps to current val */

-    indexptr = cquantize->colorindex[i];

-    val = 0;

-    k = largest_input_value(cinfo, i, 0, nci-1);

-    for (j = 0; j <= MAXJSAMPLE; j++) {

-      while (j > k)             /* advance val if past boundary */

-        k = largest_input_value(cinfo, i, ++val, nci-1);

-      /* premultiply so that no multiplication needed in main processing */

-      indexptr[j] = (JSAMPLE) (val * blksize);

-    }

-    /* Pad at both ends if necessary */

-    if (pad)

-      for (j = 1; j <= MAXJSAMPLE; j++) {

-        indexptr[-j] = indexptr[0];

-        indexptr[MAXJSAMPLE+j] = indexptr[MAXJSAMPLE];

-      }

-  }

-}

-

-

-/*

- * Create an ordered-dither array for a component having ncolors

- * distinct output values.

- */

-

-LOCAL(ODITHER_MATRIX_PTR)

-make_odither_array (j_decompress_ptr cinfo, int ncolors)

-{

-  ODITHER_MATRIX_PTR odither;

-  int j,k;

-  INT32 num,den;

-

-  odither = (ODITHER_MATRIX_PTR)

-    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,

-                                SIZEOF(ODITHER_MATRIX));

-  /* The inter-value distance for this color is MAXJSAMPLE/(ncolors-1).

-   * Hence the dither value for the matrix cell with fill order f

-   * (f=0..N-1) should be (N-1-2*f)/(2*N) * MAXJSAMPLE/(ncolors-1).

-   * On 16-bit-int machine, be careful to avoid overflow.

-   */

-  den = 2 * ODITHER_CELLS * ((INT32) (ncolors - 1));

-  for (j = 0; j < ODITHER_SIZE; j++) {

-    for (k = 0; k < ODITHER_SIZE; k++) {

-      num = ((INT32) (ODITHER_CELLS-1 - 2*((int)base_dither_matrix[j][k])))

-            * MAXJSAMPLE;

-      /* Ensure round towards zero despite C's lack of consistency

-       * about rounding negative values in integer division...

-       */

-      odither[j][k] = (int) (num<0 ? -((-num)/den) : num/den);

-    }

-  }

-  return odither;

-}

-

-

-/*

- * Create the ordered-dither tables.

- * Components having the same number of representative colors may 

- * share a dither table.

- */

-

-LOCAL(void)

-create_odither_tables (j_decompress_ptr cinfo)

-{

-  my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;

-  ODITHER_MATRIX_PTR odither;

-  int i, j, nci;

-

-  for (i = 0; i < cinfo->out_color_components; i++) {

-    nci = cquantize->Ncolors[i]; /* # of distinct values for this color */

-    odither = NULL;             /* search for matching prior component */

-    for (j = 0; j < i; j++) {

-      if (nci == cquantize->Ncolors[j]) {

-        odither = cquantize->odither[j];

-        break;

-      }

-    }

-    if (odither == NULL)        /* need a new table? */

-      odither = make_odither_array(cinfo, nci);

-    cquantize->odither[i] = odither;

-  }

-}

-

-

-/*

- * Map some rows of pixels to the output colormapped representation.

- */

-

-METHODDEF(void)

-color_quantize (j_decompress_ptr cinfo, JSAMPARRAY input_buf,

-                JSAMPARRAY output_buf, int num_rows)

-/* General case, no dithering */

-{

-  my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;

-  JSAMPARRAY colorindex = cquantize->colorindex;

-  register int pixcode, ci;

-  register JSAMPROW ptrin, ptrout;

-  int row;

-  JDIMENSION col;

-  JDIMENSION width = cinfo->output_width;

-  register int nc = cinfo->out_color_components;

-

-  for (row = 0; row < num_rows; row++) {

-    ptrin = input_buf[row];

-    ptrout = output_buf[row];

-    for (col = width; col > 0; col--) {

-      pixcode = 0;

-      for (ci = 0; ci < nc; ci++) {

-        pixcode += GETJSAMPLE(colorindex[ci][GETJSAMPLE(*ptrin++)]);

-      }

-      *ptrout++ = (JSAMPLE) pixcode;

-    }

-  }

-}

-

-

-METHODDEF(void)

-color_quantize3 (j_decompress_ptr cinfo, JSAMPARRAY input_buf,

-                 JSAMPARRAY output_buf, int num_rows)

-/* Fast path for out_color_components==3, no dithering */

-{

-  my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;

-  register int pixcode;

-  register JSAMPROW ptrin, ptrout;

-  JSAMPROW colorindex0 = cquantize->colorindex[0];

-  JSAMPROW colorindex1 = cquantize->colorindex[1];

-  JSAMPROW colorindex2 = cquantize->colorindex[2];

-  int row;

-  JDIMENSION col;

-  JDIMENSION width = cinfo->output_width;

-

-  for (row = 0; row < num_rows; row++) {

-    ptrin = input_buf[row];

-    ptrout = output_buf[row];

-    for (col = width; col > 0; col--) {

-      pixcode  = GETJSAMPLE(colorindex0[GETJSAMPLE(*ptrin++)]);

-      pixcode += GETJSAMPLE(colorindex1[GETJSAMPLE(*ptrin++)]);

-      pixcode += GETJSAMPLE(colorindex2[GETJSAMPLE(*ptrin++)]);

-      *ptrout++ = (JSAMPLE) pixcode;

-    }

-  }

-}

-

-

-METHODDEF(void)

-quantize_ord_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf,

-                     JSAMPARRAY output_buf, int num_rows)

-/* General case, with ordered dithering */

-{

-  my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;

-  register JSAMPROW input_ptr;

-  register JSAMPROW output_ptr;

-  JSAMPROW colorindex_ci;

-  int * dither;                 /* points to active row of dither matrix */

-  int row_index, col_index;     /* current indexes into dither matrix */

-  int nc = cinfo->out_color_components;

-  int ci;

-  int row;

-  JDIMENSION col;

-  JDIMENSION width = cinfo->output_width;

-

-  for (row = 0; row < num_rows; row++) {

-    /* Initialize output values to 0 so can process components separately */

-    FMEMZERO((void FAR *) output_buf[row],

-             (size_t) (width * SIZEOF(JSAMPLE)));

-    row_index = cquantize->row_index;

-    for (ci = 0; ci < nc; ci++) {

-      input_ptr = input_buf[row] + ci;

-      output_ptr = output_buf[row];

-      colorindex_ci = cquantize->colorindex[ci];

-      dither = cquantize->odither[ci][row_index];

-      col_index = 0;

-

-      for (col = width; col > 0; col--) {

-        /* Form pixel value + dither, range-limit to 0..MAXJSAMPLE,

-         * select output value, accumulate into output code for this pixel.

-         * Range-limiting need not be done explicitly, as we have extended

-         * the colorindex table to produce the right answers for out-of-range

-         * inputs.  The maximum dither is +- MAXJSAMPLE; this sets the

-         * required amount of padding.

-         */

-        *output_ptr += colorindex_ci[GETJSAMPLE(*input_ptr)+dither[col_index]];

-        input_ptr += nc;

-        output_ptr++;

-        col_index = (col_index + 1) & ODITHER_MASK;

-      }

-    }

-    /* Advance row index for next row */

-    row_index = (row_index + 1) & ODITHER_MASK;

-    cquantize->row_index = row_index;

-  }

-}

-

-

-METHODDEF(void)

-quantize3_ord_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf,

-                      JSAMPARRAY output_buf, int num_rows)

-/* Fast path for out_color_components==3, with ordered dithering */

-{

-  my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;

-  register int pixcode;

-  register JSAMPROW input_ptr;

-  register JSAMPROW output_ptr;

-  JSAMPROW colorindex0 = cquantize->colorindex[0];

-  JSAMPROW colorindex1 = cquantize->colorindex[1];

-  JSAMPROW colorindex2 = cquantize->colorindex[2];

-  int * dither0;                /* points to active row of dither matrix */

-  int * dither1;

-  int * dither2;

-  int row_index, col_index;     /* current indexes into dither matrix */

-  int row;

-  JDIMENSION col;

-  JDIMENSION width = cinfo->output_width;

-

-  for (row = 0; row < num_rows; row++) {

-    row_index = cquantize->row_index;

-    input_ptr = input_buf[row];

-    output_ptr = output_buf[row];

-    dither0 = cquantize->odither[0][row_index];

-    dither1 = cquantize->odither[1][row_index];

-    dither2 = cquantize->odither[2][row_index];

-    col_index = 0;

-

-    for (col = width; col > 0; col--) {

-      pixcode  = GETJSAMPLE(colorindex0[GETJSAMPLE(*input_ptr++) +

-                                        dither0[col_index]]);

-      pixcode += GETJSAMPLE(colorindex1[GETJSAMPLE(*input_ptr++) +

-                                        dither1[col_index]]);

-      pixcode += GETJSAMPLE(colorindex2[GETJSAMPLE(*input_ptr++) +

-                                        dither2[col_index]]);

-      *output_ptr++ = (JSAMPLE) pixcode;

-      col_index = (col_index + 1) & ODITHER_MASK;

-    }

-    row_index = (row_index + 1) & ODITHER_MASK;

-    cquantize->row_index = row_index;

-  }

-}

-

-

-METHODDEF(void)

-quantize_fs_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf,

-                    JSAMPARRAY output_buf, int num_rows)

-/* General case, with Floyd-Steinberg dithering */

-{

-  my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;

-  register LOCFSERROR cur;      /* current error or pixel value */

-  LOCFSERROR belowerr;          /* error for pixel below cur */

-  LOCFSERROR bpreverr;          /* error for below/prev col */

-  LOCFSERROR bnexterr;          /* error for below/next col */

-  LOCFSERROR delta;

-  register FSERRPTR errorptr;   /* => fserrors[] at column before current */

-  register JSAMPROW input_ptr;

-  register JSAMPROW output_ptr;

-  JSAMPROW colorindex_ci;

-  JSAMPROW colormap_ci;

-  int pixcode;

-  int nc = cinfo->out_color_components;

-  int dir;                      /* 1 for left-to-right, -1 for right-to-left */

-  int dirnc;                    /* dir * nc */

-  int ci;

-  int row;

-  JDIMENSION col;

-  JDIMENSION width = cinfo->output_width;

-  JSAMPLE *range_limit = cinfo->sample_range_limit;

-  SHIFT_TEMPS

-

-  for (row = 0; row < num_rows; row++) {

-    /* Initialize output values to 0 so can process components separately */

-    FMEMZERO((void FAR *) output_buf[row],

-             (size_t) (width * SIZEOF(JSAMPLE)));

-    for (ci = 0; ci < nc; ci++) {

-      input_ptr = input_buf[row] + ci;

-      output_ptr = output_buf[row];

-      if (cquantize->on_odd_row) {

-        /* work right to left in this row */

-        input_ptr += (width-1) * nc; /* so point to rightmost pixel */

-        output_ptr += width-1;

-        dir = -1;

-        dirnc = -nc;

-        errorptr = cquantize->fserrors[ci] + (width+1); /* => entry after last column */

-      } else {

-        /* work left to right in this row */

-        dir = 1;

-        dirnc = nc;

-        errorptr = cquantize->fserrors[ci]; /* => entry before first column */

-      }

-      colorindex_ci = cquantize->colorindex[ci];

-      colormap_ci = cquantize->sv_colormap[ci];

-      /* Preset error values: no error propagated to first pixel from left */

-      cur = 0;

-      /* and no error propagated to row below yet */

-      belowerr = bpreverr = 0;

-

-      for (col = width; col > 0; col--) {

-        /* cur holds the error propagated from the previous pixel on the

-         * current line.  Add the error propagated from the previous line

-         * to form the complete error correction term for this pixel, and

-         * round the error term (which is expressed * 16) to an integer.

-         * RIGHT_SHIFT rounds towards minus infinity, so adding 8 is correct

-         * for either sign of the error value.

-         * Note: errorptr points to *previous* column's array entry.

-         */

-        cur = RIGHT_SHIFT(cur + errorptr[dir] + 8, 4);

-        /* Form pixel value + error, and range-limit to 0..MAXJSAMPLE.

-         * The maximum error is +- MAXJSAMPLE; this sets the required size

-         * of the range_limit array.

-         */

-        cur += GETJSAMPLE(*input_ptr);

-        cur = GETJSAMPLE(range_limit[cur]);

-        /* Select output value, accumulate into output code for this pixel */

-        pixcode = GETJSAMPLE(colorindex_ci[cur]);

-        *output_ptr += (JSAMPLE) pixcode;

-        /* Compute actual representation error at this pixel */

-        /* Note: we can do this even though we don't have the final */

-        /* pixel code, because the colormap is orthogonal. */

-        cur -= GETJSAMPLE(colormap_ci[pixcode]);

-        /* Compute error fractions to be propagated to adjacent pixels.

-         * Add these into the running sums, and simultaneously shift the

-         * next-line error sums left by 1 column.

-         */

-        bnexterr = cur;

-        delta = cur * 2;

-        cur += delta;           /* form error * 3 */

-        errorptr[0] = (FSERROR) (bpreverr + cur);

-        cur += delta;           /* form error * 5 */

-        bpreverr = belowerr + cur;

-        belowerr = bnexterr;

-        cur += delta;           /* form error * 7 */

-        /* At this point cur contains the 7/16 error value to be propagated

-         * to the next pixel on the current line, and all the errors for the

-         * next line have been shifted over. We are therefore ready to move on.

-         */

-        input_ptr += dirnc;     /* advance input ptr to next column */

-        output_ptr += dir;      /* advance output ptr to next column */

-        errorptr += dir;        /* advance errorptr to current column */

-      }

-      /* Post-loop cleanup: we must unload the final error value into the

-       * final fserrors[] entry.  Note we need not unload belowerr because

-       * it is for the dummy column before or after the actual array.

-       */

-      errorptr[0] = (FSERROR) bpreverr; /* unload prev err into array */

-    }

-    cquantize->on_odd_row = (cquantize->on_odd_row ? FALSE : TRUE);

-  }

-}

-

-

-/*

- * Allocate workspace for Floyd-Steinberg errors.

- */

-

-LOCAL(void)

-alloc_fs_workspace (j_decompress_ptr cinfo)

-{

-  my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;

-  size_t arraysize;

-  int i;

-

-  arraysize = (size_t) ((cinfo->output_width + 2) * SIZEOF(FSERROR));

-  for (i = 0; i < cinfo->out_color_components; i++) {

-    cquantize->fserrors[i] = (FSERRPTR)

-      (*cinfo->mem->alloc_large)((j_common_ptr) cinfo, JPOOL_IMAGE, arraysize);

-  }

-}

-

-

-/*

- * Initialize for one-pass color quantization.

- */

-

-METHODDEF(void)

-start_pass_1_quant (j_decompress_ptr cinfo, boolean is_pre_scan)

-{

-  my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;

-  size_t arraysize;

-  int i;

-

-  /* Install my colormap. */

-  cinfo->colormap = cquantize->sv_colormap;

-  cinfo->actual_number_of_colors = cquantize->sv_actual;

-

-  /* Initialize for desired dithering mode. */

-  switch (cinfo->dither_mode) {

-  case JDITHER_NONE:

-    if (cinfo->out_color_components == 3)

-      cquantize->pub.color_quantize = color_quantize3;

-    else

-      cquantize->pub.color_quantize = color_quantize;

-    break;

-  case JDITHER_ORDERED:

-    if (cinfo->out_color_components == 3)

-      cquantize->pub.color_quantize = quantize3_ord_dither;

-    else

-      cquantize->pub.color_quantize = quantize_ord_dither;

-    cquantize->row_index = 0;   /* initialize state for ordered dither */

-    /* If user changed to ordered dither from another mode,

-     * we must recreate the color index table with padding.

-     * This will cost extra space, but probably isn't very likely.

-     */

-    if (! cquantize->is_padded)

-      create_colorindex(cinfo);

-    /* Create ordered-dither tables if we didn't already. */

-    if (cquantize->odither[0] == NULL)

-      create_odither_tables(cinfo);

-    break;

-  case JDITHER_FS:

-    cquantize->pub.color_quantize = quantize_fs_dither;

-    cquantize->on_odd_row = FALSE; /* initialize state for F-S dither */

-    /* Allocate Floyd-Steinberg workspace if didn't already. */

-    if (cquantize->fserrors[0] == NULL)

-      alloc_fs_workspace(cinfo);

-    /* Initialize the propagated errors to zero. */

-    arraysize = (size_t) ((cinfo->output_width + 2) * SIZEOF(FSERROR));

-    for (i = 0; i < cinfo->out_color_components; i++)

-      FMEMZERO((void FAR *) cquantize->fserrors[i], arraysize);

-    break;

-  default:

-    ERREXIT(cinfo, JERR_NOT_COMPILED);

-    break;

-  }

-}

-

-

-/*

- * Finish up at the end of the pass.

- */

-

-METHODDEF(void)

-finish_pass_1_quant (j_decompress_ptr cinfo)

-{

-  /* no work in 1-pass case */

-}

-

-

-/*

- * Switch to a new external colormap between output passes.

- * Shouldn't get to this module!

- */

-

-METHODDEF(void)

-new_color_map_1_quant (j_decompress_ptr cinfo)

-{

-  ERREXIT(cinfo, JERR_MODE_CHANGE);

-}

-

-

-/*

- * Module initialization routine for 1-pass color quantization.

- */

-

-GLOBAL(void)

-jinit_1pass_quantizer (j_decompress_ptr cinfo)

-{

-  my_cquantize_ptr cquantize;

-

-  cquantize = (my_cquantize_ptr)

-    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,

-                                SIZEOF(my_cquantizer));

-  cinfo->cquantize = (struct jpeg_color_quantizer *) cquantize;

-  cquantize->pub.start_pass = start_pass_1_quant;

-  cquantize->pub.finish_pass = finish_pass_1_quant;

-  cquantize->pub.new_color_map = new_color_map_1_quant;

-  cquantize->fserrors[0] = NULL; /* Flag FS workspace not allocated */

-  cquantize->odither[0] = NULL; /* Also flag odither arrays not allocated */

-

-  /* Make sure my internal arrays won't overflow */

-  if (cinfo->out_color_components > MAX_Q_COMPS)

-    ERREXIT1(cinfo, JERR_QUANT_COMPONENTS, MAX_Q_COMPS);

-  /* Make sure colormap indexes can be represented by JSAMPLEs */

-  if (cinfo->desired_number_of_colors > (MAXJSAMPLE+1))

-    ERREXIT1(cinfo, JERR_QUANT_MANY_COLORS, MAXJSAMPLE+1);

-

-  /* Create the colormap and color index table. */

-  create_colormap(cinfo);

-  create_colorindex(cinfo);

-

-  /* Allocate Floyd-Steinberg workspace now if requested.

-   * We do this now since it is FAR storage and may affect the memory

-   * manager's space calculations.  If the user changes to FS dither

-   * mode in a later pass, we will allocate the space then, and will

-   * possibly overrun the max_memory_to_use setting.

-   */

-  if (cinfo->dither_mode == JDITHER_FS)

-    alloc_fs_workspace(cinfo);

-}

-

-#endif /* QUANT_1PASS_SUPPORTED */

+/*
+ * jquant1.c
+ *
+ * Copyright (C) 1991-1996, Thomas G. Lane.
+ * Modified 2011 by Guido Vollbeding.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains 1-pass color quantization (color mapping) routines.
+ * These routines provide mapping to a fixed color map using equally spaced
+ * color values.  Optional Floyd-Steinberg or ordered dithering is available.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+#ifdef QUANT_1PASS_SUPPORTED
+
+
+/*
+ * The main purpose of 1-pass quantization is to provide a fast, if not very
+ * high quality, colormapped output capability.  A 2-pass quantizer usually
+ * gives better visual quality; however, for quantized grayscale output this
+ * quantizer is perfectly adequate.  Dithering is highly recommended with this
+ * quantizer, though you can turn it off if you really want to.
+ *
+ * In 1-pass quantization the colormap must be chosen in advance of seeing the
+ * image.  We use a map consisting of all combinations of Ncolors[i] color
+ * values for the i'th component.  The Ncolors[] values are chosen so that
+ * their product, the total number of colors, is no more than that requested.
+ * (In most cases, the product will be somewhat less.)
+ *
+ * Since the colormap is orthogonal, the representative value for each color
+ * component can be determined without considering the other components;
+ * then these indexes can be combined into a colormap index by a standard
+ * N-dimensional-array-subscript calculation.  Most of the arithmetic involved
+ * can be precalculated and stored in the lookup table colorindex[].
+ * colorindex[i][j] maps pixel value j in component i to the nearest
+ * representative value (grid plane) for that component; this index is
+ * multiplied by the array stride for component i, so that the
+ * index of the colormap entry closest to a given pixel value is just
+ *    sum( colorindex[component-number][pixel-component-value] )
+ * Aside from being fast, this scheme allows for variable spacing between
+ * representative values with no additional lookup cost.
+ *
+ * If gamma correction has been applied in color conversion, it might be wise
+ * to adjust the color grid spacing so that the representative colors are
+ * equidistant in linear space.  At this writing, gamma correction is not
+ * implemented by jdcolor, so nothing is done here.
+ */
+
+
+/* Declarations for ordered dithering.
+ *
+ * We use a standard 16x16 ordered dither array.  The basic concept of ordered
+ * dithering is described in many references, for instance Dale Schumacher's
+ * chapter II.2 of Graphics Gems II (James Arvo, ed. Academic Press, 1991).
+ * In place of Schumacher's comparisons against a "threshold" value, we add a
+ * "dither" value to the input pixel and then round the result to the nearest
+ * output value.  The dither value is equivalent to (0.5 - threshold) times
+ * the distance between output values.  For ordered dithering, we assume that
+ * the output colors are equally spaced; if not, results will probably be
+ * worse, since the dither may be too much or too little at a given point.
+ *
+ * The normal calculation would be to form pixel value + dither, range-limit
+ * this to 0..MAXJSAMPLE, and then index into the colorindex table as usual.
+ * We can skip the separate range-limiting step by extending the colorindex
+ * table in both directions.
+ */
+
+#define ODITHER_SIZE  16        /* dimension of dither matrix */
+/* NB: if ODITHER_SIZE is not a power of 2, ODITHER_MASK uses will break */
+#define ODITHER_CELLS (ODITHER_SIZE*ODITHER_SIZE)       /* # cells in matrix */
+#define ODITHER_MASK  (ODITHER_SIZE-1) /* mask for wrapping around counters */
+
+typedef int ODITHER_MATRIX[ODITHER_SIZE][ODITHER_SIZE];
+typedef int (*ODITHER_MATRIX_PTR)[ODITHER_SIZE];
+
+static const UINT8 base_dither_matrix[ODITHER_SIZE][ODITHER_SIZE] = {
+  /* Bayer's order-4 dither array.  Generated by the code given in
+   * Stephen Hawley's article "Ordered Dithering" in Graphics Gems I.
+   * The values in this array must range from 0 to ODITHER_CELLS-1.
+   */
+  {   0,192, 48,240, 12,204, 60,252,  3,195, 51,243, 15,207, 63,255 },
+  { 128, 64,176,112,140, 76,188,124,131, 67,179,115,143, 79,191,127 },
+  {  32,224, 16,208, 44,236, 28,220, 35,227, 19,211, 47,239, 31,223 },
+  { 160, 96,144, 80,172,108,156, 92,163, 99,147, 83,175,111,159, 95 },
+  {   8,200, 56,248,  4,196, 52,244, 11,203, 59,251,  7,199, 55,247 },
+  { 136, 72,184,120,132, 68,180,116,139, 75,187,123,135, 71,183,119 },
+  {  40,232, 24,216, 36,228, 20,212, 43,235, 27,219, 39,231, 23,215 },
+  { 168,104,152, 88,164,100,148, 84,171,107,155, 91,167,103,151, 87 },
+  {   2,194, 50,242, 14,206, 62,254,  1,193, 49,241, 13,205, 61,253 },
+  { 130, 66,178,114,142, 78,190,126,129, 65,177,113,141, 77,189,125 },
+  {  34,226, 18,210, 46,238, 30,222, 33,225, 17,209, 45,237, 29,221 },
+  { 162, 98,146, 82,174,110,158, 94,161, 97,145, 81,173,109,157, 93 },
+  {  10,202, 58,250,  6,198, 54,246,  9,201, 57,249,  5,197, 53,245 },
+  { 138, 74,186,122,134, 70,182,118,137, 73,185,121,133, 69,181,117 },
+  {  42,234, 26,218, 38,230, 22,214, 41,233, 25,217, 37,229, 21,213 },
+  { 170,106,154, 90,166,102,150, 86,169,105,153, 89,165,101,149, 85 }
+};
+
+
+/* Declarations for Floyd-Steinberg dithering.
+ *
+ * Errors are accumulated into the array fserrors[], at a resolution of
+ * 1/16th of a pixel count.  The error at a given pixel is propagated
+ * to its not-yet-processed neighbors using the standard F-S fractions,
+ *              ...     (here)  7/16
+ *              3/16    5/16    1/16
+ * We work left-to-right on even rows, right-to-left on odd rows.
+ *
+ * We can get away with a single array (holding one row's worth of errors)
+ * by using it to store the current row's errors at pixel columns not yet
+ * processed, but the next row's errors at columns already processed.  We
+ * need only a few extra variables to hold the errors immediately around the
+ * current column.  (If we are lucky, those variables are in registers, but
+ * even if not, they're probably cheaper to access than array elements are.)
+ *
+ * The fserrors[] array is indexed [component#][position].
+ * We provide (#columns + 2) entries per component; the extra entry at each
+ * end saves us from special-casing the first and last pixels.
+ *
+ * Note: on a wide image, we might not have enough room in a PC's near data
+ * segment to hold the error array; so it is allocated with alloc_large.
+ */
+
+#if BITS_IN_JSAMPLE == 8
+typedef INT16 FSERROR;          /* 16 bits should be enough */
+typedef int LOCFSERROR;         /* use 'int' for calculation temps */
+#else
+typedef INT32 FSERROR;          /* may need more than 16 bits */
+typedef INT32 LOCFSERROR;       /* be sure calculation temps are big enough */
+#endif
+
+typedef FSERROR FAR *FSERRPTR;  /* pointer to error array (in FAR storage!) */
+
+
+/* Private subobject */
+
+#define MAX_Q_COMPS 4           /* max components I can handle */
+
+typedef struct {
+  struct jpeg_color_quantizer pub; /* public fields */
+
+  /* Initially allocated colormap is saved here */
+  JSAMPARRAY sv_colormap;       /* The color map as a 2-D pixel array */
+  int sv_actual;                /* number of entries in use */
+
+  JSAMPARRAY colorindex;        /* Precomputed mapping for speed */
+  /* colorindex[i][j] = index of color closest to pixel value j in component i,
+   * premultiplied as described above.  Since colormap indexes must fit into
+   * JSAMPLEs, the entries of this array will too.
+   */
+  boolean is_padded;            /* is the colorindex padded for odither? */
+
+  int Ncolors[MAX_Q_COMPS];     /* # of values alloced to each component */
+
+  /* Variables for ordered dithering */
+  int row_index;                /* cur row's vertical index in dither matrix */
+  ODITHER_MATRIX_PTR odither[MAX_Q_COMPS]; /* one dither array per component */
+
+  /* Variables for Floyd-Steinberg dithering */
+  FSERRPTR fserrors[MAX_Q_COMPS]; /* accumulated errors */
+  boolean on_odd_row;           /* flag to remember which row we are on */
+} my_cquantizer;
+
+typedef my_cquantizer * my_cquantize_ptr;
+
+
+/*
+ * Policy-making subroutines for create_colormap and create_colorindex.
+ * These routines determine the colormap to be used.  The rest of the module
+ * only assumes that the colormap is orthogonal.
+ *
+ *  * select_ncolors decides how to divvy up the available colors
+ *    among the components.
+ *  * output_value defines the set of representative values for a component.
+ *  * largest_input_value defines the mapping from input values to
+ *    representative values for a component.
+ * Note that the latter two routines may impose different policies for
+ * different components, though this is not currently done.
+ */
+
+
+LOCAL(int)
+select_ncolors (j_decompress_ptr cinfo, int Ncolors[])
+/* Determine allocation of desired colors to components, */
+/* and fill in Ncolors[] array to indicate choice. */
+/* Return value is total number of colors (product of Ncolors[] values). */
+{
+  int nc = cinfo->out_color_components; /* number of color components */
+  int max_colors = cinfo->desired_number_of_colors;
+  int total_colors, iroot, i, j;
+  boolean changed;
+  long temp;
+  static const int RGB_order[3] = { RGB_GREEN, RGB_RED, RGB_BLUE };
+
+  /* We can allocate at least the nc'th root of max_colors per component. */
+  /* Compute floor(nc'th root of max_colors). */
+  iroot = 1;
+  do {
+    iroot++;
+    temp = iroot;               /* set temp = iroot ** nc */
+    for (i = 1; i < nc; i++)
+      temp *= iroot;
+  } while (temp <= (long) max_colors); /* repeat till iroot exceeds root */
+  iroot--;                      /* now iroot = floor(root) */
+
+  /* Must have at least 2 color values per component */
+  if (iroot < 2)
+    ERREXIT1(cinfo, JERR_QUANT_FEW_COLORS, (int) temp);
+
+  /* Initialize to iroot color values for each component */
+  total_colors = 1;
+  for (i = 0; i < nc; i++) {
+    Ncolors[i] = iroot;
+    total_colors *= iroot;
+  }
+  /* We may be able to increment the count for one or more components without
+   * exceeding max_colors, though we know not all can be incremented.
+   * Sometimes, the first component can be incremented more than once!
+   * (Example: for 16 colors, we start at 2*2*2, go to 3*2*2, then 4*2*2.)
+   * In RGB colorspace, try to increment G first, then R, then B.
+   */
+  do {
+    changed = FALSE;
+    for (i = 0; i < nc; i++) {
+      j = (cinfo->out_color_space == JCS_RGB ? RGB_order[i] : i);
+      /* calculate new total_colors if Ncolors[j] is incremented */
+      temp = total_colors / Ncolors[j];
+      temp *= Ncolors[j]+1;     /* done in long arith to avoid oflo */
+      if (temp > (long) max_colors)
+        break;                  /* won't fit, done with this pass */
+      Ncolors[j]++;             /* OK, apply the increment */
+      total_colors = (int) temp;
+      changed = TRUE;
+    }
+  } while (changed);
+
+  return total_colors;
+}
+
+
+LOCAL(int)
+output_value (j_decompress_ptr cinfo, int ci, int j, int maxj)
+/* Return j'th output value, where j will range from 0 to maxj */
+/* The output values must fall in 0..MAXJSAMPLE in increasing order */
+{
+  /* We always provide values 0 and MAXJSAMPLE for each component;
+   * any additional values are equally spaced between these limits.
+   * (Forcing the upper and lower values to the limits ensures that
+   * dithering can't produce a color outside the selected gamut.)
+   */
+  return (int) (((INT32) j * MAXJSAMPLE + maxj/2) / maxj);
+}
+
+
+LOCAL(int)
+largest_input_value (j_decompress_ptr cinfo, int ci, int j, int maxj)
+/* Return largest input value that should map to j'th output value */
+/* Must have largest(j=0) >= 0, and largest(j=maxj) >= MAXJSAMPLE */
+{
+  /* Breakpoints are halfway between values returned by output_value */
+  return (int) (((INT32) (2*j + 1) * MAXJSAMPLE + maxj) / (2*maxj));
+}
+
+
+/*
+ * Create the colormap.
+ */
+
+LOCAL(void)
+create_colormap (j_decompress_ptr cinfo)
+{
+  my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+  JSAMPARRAY colormap;          /* Created colormap */
+  int total_colors;             /* Number of distinct output colors */
+  int i,j,k, nci, blksize, blkdist, ptr, val;
+
+  /* Select number of colors for each component */
+  total_colors = select_ncolors(cinfo, cquantize->Ncolors);
+
+  /* Report selected color counts */
+  if (cinfo->out_color_components == 3)
+    TRACEMS4(cinfo, 1, JTRC_QUANT_3_NCOLORS,
+             total_colors, cquantize->Ncolors[0],
+             cquantize->Ncolors[1], cquantize->Ncolors[2]);
+  else
+    TRACEMS1(cinfo, 1, JTRC_QUANT_NCOLORS, total_colors);
+
+  /* Allocate and fill in the colormap. */
+  /* The colors are ordered in the map in standard row-major order, */
+  /* i.e. rightmost (highest-indexed) color changes most rapidly. */
+
+  colormap = (*cinfo->mem->alloc_sarray)
+    ((j_common_ptr) cinfo, JPOOL_IMAGE,
+     (JDIMENSION) total_colors, (JDIMENSION) cinfo->out_color_components);
+
+  /* blksize is number of adjacent repeated entries for a component */
+  /* blkdist is distance between groups of identical entries for a component */
+  blkdist = total_colors;
+
+  for (i = 0; i < cinfo->out_color_components; i++) {
+    /* fill in colormap entries for i'th color component */
+    nci = cquantize->Ncolors[i]; /* # of distinct values for this color */
+    blksize = blkdist / nci;
+    for (j = 0; j < nci; j++) {
+      /* Compute j'th output value (out of nci) for component */
+      val = output_value(cinfo, i, j, nci-1);
+      /* Fill in all colormap entries that have this value of this component */
+      for (ptr = j * blksize; ptr < total_colors; ptr += blkdist) {
+        /* fill in blksize entries beginning at ptr */
+        for (k = 0; k < blksize; k++)
+          colormap[i][ptr+k] = (JSAMPLE) val;
+      }
+    }
+    blkdist = blksize;          /* blksize of this color is blkdist of next */
+  }
+
+  /* Save the colormap in private storage,
+   * where it will survive color quantization mode changes.
+   */
+  cquantize->sv_colormap = colormap;
+  cquantize->sv_actual = total_colors;
+}
+
+
+/*
+ * Create the color index table.
+ */
+
+LOCAL(void)
+create_colorindex (j_decompress_ptr cinfo)
+{
+  my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+  JSAMPROW indexptr;
+  int i,j,k, nci, blksize, val, pad;
+
+  /* For ordered dither, we pad the color index tables by MAXJSAMPLE in
+   * each direction (input index values can be -MAXJSAMPLE .. 2*MAXJSAMPLE).
+   * This is not necessary in the other dithering modes.  However, we
+   * flag whether it was done in case user changes dithering mode.
+   */
+  if (cinfo->dither_mode == JDITHER_ORDERED) {
+    pad = MAXJSAMPLE*2;
+    cquantize->is_padded = TRUE;
+  } else {
+    pad = 0;
+    cquantize->is_padded = FALSE;
+  }
+
+  cquantize->colorindex = (*cinfo->mem->alloc_sarray)
+    ((j_common_ptr) cinfo, JPOOL_IMAGE,
+     (JDIMENSION) (MAXJSAMPLE+1 + pad),
+     (JDIMENSION) cinfo->out_color_components);
+
+  /* blksize is number of adjacent repeated entries for a component */
+  blksize = cquantize->sv_actual;
+
+  for (i = 0; i < cinfo->out_color_components; i++) {
+    /* fill in colorindex entries for i'th color component */
+    nci = cquantize->Ncolors[i]; /* # of distinct values for this color */
+    blksize = blksize / nci;
+
+    /* adjust colorindex pointers to provide padding at negative indexes. */
+    if (pad)
+      cquantize->colorindex[i] += MAXJSAMPLE;
+
+    /* in loop, val = index of current output value, */
+    /* and k = largest j that maps to current val */
+    indexptr = cquantize->colorindex[i];
+    val = 0;
+    k = largest_input_value(cinfo, i, 0, nci-1);
+    for (j = 0; j <= MAXJSAMPLE; j++) {
+      while (j > k)             /* advance val if past boundary */
+        k = largest_input_value(cinfo, i, ++val, nci-1);
+      /* premultiply so that no multiplication needed in main processing */
+      indexptr[j] = (JSAMPLE) (val * blksize);
+    }
+    /* Pad at both ends if necessary */
+    if (pad)
+      for (j = 1; j <= MAXJSAMPLE; j++) {
+        indexptr[-j] = indexptr[0];
+        indexptr[MAXJSAMPLE+j] = indexptr[MAXJSAMPLE];
+      }
+  }
+}
+
+
+/*
+ * Create an ordered-dither array for a component having ncolors
+ * distinct output values.
+ */
+
+LOCAL(ODITHER_MATRIX_PTR)
+make_odither_array (j_decompress_ptr cinfo, int ncolors)
+{
+  ODITHER_MATRIX_PTR odither;
+  int j,k;
+  INT32 num,den;
+
+  odither = (ODITHER_MATRIX_PTR)
+    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+                                SIZEOF(ODITHER_MATRIX));
+  /* The inter-value distance for this color is MAXJSAMPLE/(ncolors-1).
+   * Hence the dither value for the matrix cell with fill order f
+   * (f=0..N-1) should be (N-1-2*f)/(2*N) * MAXJSAMPLE/(ncolors-1).
+   * On 16-bit-int machine, be careful to avoid overflow.
+   */
+  den = 2 * ODITHER_CELLS * ((INT32) (ncolors - 1));
+  for (j = 0; j < ODITHER_SIZE; j++) {
+    for (k = 0; k < ODITHER_SIZE; k++) {
+      num = ((INT32) (ODITHER_CELLS-1 - 2*((int)base_dither_matrix[j][k])))
+            * MAXJSAMPLE;
+      /* Ensure round towards zero despite C's lack of consistency
+       * about rounding negative values in integer division...
+       */
+      odither[j][k] = (int) (num<0 ? -((-num)/den) : num/den);
+    }
+  }
+  return odither;
+}
+
+
+/*
+ * Create the ordered-dither tables.
+ * Components having the same number of representative colors may 
+ * share a dither table.
+ */
+
+LOCAL(void)
+create_odither_tables (j_decompress_ptr cinfo)
+{
+  my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+  ODITHER_MATRIX_PTR odither;
+  int i, j, nci;
+
+  for (i = 0; i < cinfo->out_color_components; i++) {
+    nci = cquantize->Ncolors[i]; /* # of distinct values for this color */
+    odither = NULL;             /* search for matching prior component */
+    for (j = 0; j < i; j++) {
+      if (nci == cquantize->Ncolors[j]) {
+        odither = cquantize->odither[j];
+        break;
+      }
+    }
+    if (odither == NULL)        /* need a new table? */
+      odither = make_odither_array(cinfo, nci);
+    cquantize->odither[i] = odither;
+  }
+}
+
+
+/*
+ * Map some rows of pixels to the output colormapped representation.
+ */
+
+METHODDEF(void)
+color_quantize (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
+                JSAMPARRAY output_buf, int num_rows)
+/* General case, no dithering */
+{
+  my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+  JSAMPARRAY colorindex = cquantize->colorindex;
+  register int pixcode, ci;
+  register JSAMPROW ptrin, ptrout;
+  int row;
+  JDIMENSION col;
+  JDIMENSION width = cinfo->output_width;
+  register int nc = cinfo->out_color_components;
+
+  for (row = 0; row < num_rows; row++) {
+    ptrin = input_buf[row];
+    ptrout = output_buf[row];
+    for (col = width; col > 0; col--) {
+      pixcode = 0;
+      for (ci = 0; ci < nc; ci++) {
+        pixcode += GETJSAMPLE(colorindex[ci][GETJSAMPLE(*ptrin++)]);
+      }
+      *ptrout++ = (JSAMPLE) pixcode;
+    }
+  }
+}
+
+
+METHODDEF(void)
+color_quantize3 (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
+                 JSAMPARRAY output_buf, int num_rows)
+/* Fast path for out_color_components==3, no dithering */
+{
+  my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+  register int pixcode;
+  register JSAMPROW ptrin, ptrout;
+  JSAMPROW colorindex0 = cquantize->colorindex[0];
+  JSAMPROW colorindex1 = cquantize->colorindex[1];
+  JSAMPROW colorindex2 = cquantize->colorindex[2];
+  int row;
+  JDIMENSION col;
+  JDIMENSION width = cinfo->output_width;
+
+  for (row = 0; row < num_rows; row++) {
+    ptrin = input_buf[row];
+    ptrout = output_buf[row];
+    for (col = width; col > 0; col--) {
+      pixcode  = GETJSAMPLE(colorindex0[GETJSAMPLE(*ptrin++)]);
+      pixcode += GETJSAMPLE(colorindex1[GETJSAMPLE(*ptrin++)]);
+      pixcode += GETJSAMPLE(colorindex2[GETJSAMPLE(*ptrin++)]);
+      *ptrout++ = (JSAMPLE) pixcode;
+    }
+  }
+}
+
+
+METHODDEF(void)
+quantize_ord_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
+                     JSAMPARRAY output_buf, int num_rows)
+/* General case, with ordered dithering */
+{
+  my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+  register JSAMPROW input_ptr;
+  register JSAMPROW output_ptr;
+  JSAMPROW colorindex_ci;
+  int * dither;                 /* points to active row of dither matrix */
+  int row_index, col_index;     /* current indexes into dither matrix */
+  int nc = cinfo->out_color_components;
+  int ci;
+  int row;
+  JDIMENSION col;
+  JDIMENSION width = cinfo->output_width;
+
+  for (row = 0; row < num_rows; row++) {
+    /* Initialize output values to 0 so can process components separately */
+    FMEMZERO((void FAR *) output_buf[row],
+             (size_t) (width * SIZEOF(JSAMPLE)));
+    row_index = cquantize->row_index;
+    for (ci = 0; ci < nc; ci++) {
+      input_ptr = input_buf[row] + ci;
+      output_ptr = output_buf[row];
+      colorindex_ci = cquantize->colorindex[ci];
+      dither = cquantize->odither[ci][row_index];
+      col_index = 0;
+
+      for (col = width; col > 0; col--) {
+        /* Form pixel value + dither, range-limit to 0..MAXJSAMPLE,
+         * select output value, accumulate into output code for this pixel.
+         * Range-limiting need not be done explicitly, as we have extended
+         * the colorindex table to produce the right answers for out-of-range
+         * inputs.  The maximum dither is +- MAXJSAMPLE; this sets the
+         * required amount of padding.
+         */
+        *output_ptr += colorindex_ci[GETJSAMPLE(*input_ptr)+dither[col_index]];
+        input_ptr += nc;
+        output_ptr++;
+        col_index = (col_index + 1) & ODITHER_MASK;
+      }
+    }
+    /* Advance row index for next row */
+    row_index = (row_index + 1) & ODITHER_MASK;
+    cquantize->row_index = row_index;
+  }
+}
+
+
+METHODDEF(void)
+quantize3_ord_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
+                      JSAMPARRAY output_buf, int num_rows)
+/* Fast path for out_color_components==3, with ordered dithering */
+{
+  my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+  register int pixcode;
+  register JSAMPROW input_ptr;
+  register JSAMPROW output_ptr;
+  JSAMPROW colorindex0 = cquantize->colorindex[0];
+  JSAMPROW colorindex1 = cquantize->colorindex[1];
+  JSAMPROW colorindex2 = cquantize->colorindex[2];
+  int * dither0;                /* points to active row of dither matrix */
+  int * dither1;
+  int * dither2;
+  int row_index, col_index;     /* current indexes into dither matrix */
+  int row;
+  JDIMENSION col;
+  JDIMENSION width = cinfo->output_width;
+
+  for (row = 0; row < num_rows; row++) {
+    row_index = cquantize->row_index;
+    input_ptr = input_buf[row];
+    output_ptr = output_buf[row];
+    dither0 = cquantize->odither[0][row_index];
+    dither1 = cquantize->odither[1][row_index];
+    dither2 = cquantize->odither[2][row_index];
+    col_index = 0;
+
+    for (col = width; col > 0; col--) {
+      pixcode  = GETJSAMPLE(colorindex0[GETJSAMPLE(*input_ptr++) +
+                                        dither0[col_index]]);
+      pixcode += GETJSAMPLE(colorindex1[GETJSAMPLE(*input_ptr++) +
+                                        dither1[col_index]]);
+      pixcode += GETJSAMPLE(colorindex2[GETJSAMPLE(*input_ptr++) +
+                                        dither2[col_index]]);
+      *output_ptr++ = (JSAMPLE) pixcode;
+      col_index = (col_index + 1) & ODITHER_MASK;
+    }
+    row_index = (row_index + 1) & ODITHER_MASK;
+    cquantize->row_index = row_index;
+  }
+}
+
+
+METHODDEF(void)
+quantize_fs_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
+                    JSAMPARRAY output_buf, int num_rows)
+/* General case, with Floyd-Steinberg dithering */
+{
+  my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+  register LOCFSERROR cur;      /* current error or pixel value */
+  LOCFSERROR belowerr;          /* error for pixel below cur */
+  LOCFSERROR bpreverr;          /* error for below/prev col */
+  LOCFSERROR bnexterr;          /* error for below/next col */
+  LOCFSERROR delta;
+  register FSERRPTR errorptr;   /* => fserrors[] at column before current */
+  register JSAMPROW input_ptr;
+  register JSAMPROW output_ptr;
+  JSAMPROW colorindex_ci;
+  JSAMPROW colormap_ci;
+  int pixcode;
+  int nc = cinfo->out_color_components;
+  int dir;                      /* 1 for left-to-right, -1 for right-to-left */
+  int dirnc;                    /* dir * nc */
+  int ci;
+  int row;
+  JDIMENSION col;
+  JDIMENSION width = cinfo->output_width;
+  JSAMPLE *range_limit = cinfo->sample_range_limit;
+  SHIFT_TEMPS
+
+  for (row = 0; row < num_rows; row++) {
+    /* Initialize output values to 0 so can process components separately */
+    FMEMZERO((void FAR *) output_buf[row],
+             (size_t) (width * SIZEOF(JSAMPLE)));
+    for (ci = 0; ci < nc; ci++) {
+      input_ptr = input_buf[row] + ci;
+      output_ptr = output_buf[row];
+      if (cquantize->on_odd_row) {
+        /* work right to left in this row */
+        input_ptr += (width-1) * nc; /* so point to rightmost pixel */
+        output_ptr += width-1;
+        dir = -1;
+        dirnc = -nc;
+        errorptr = cquantize->fserrors[ci] + (width+1); /* => entry after last column */
+      } else {
+        /* work left to right in this row */
+        dir = 1;
+        dirnc = nc;
+        errorptr = cquantize->fserrors[ci]; /* => entry before first column */
+      }
+      colorindex_ci = cquantize->colorindex[ci];
+      colormap_ci = cquantize->sv_colormap[ci];
+      /* Preset error values: no error propagated to first pixel from left */
+      cur = 0;
+      /* and no error propagated to row below yet */
+      belowerr = bpreverr = 0;
+
+      for (col = width; col > 0; col--) {
+        /* cur holds the error propagated from the previous pixel on the
+         * current line.  Add the error propagated from the previous line
+         * to form the complete error correction term for this pixel, and
+         * round the error term (which is expressed * 16) to an integer.
+         * RIGHT_SHIFT rounds towards minus infinity, so adding 8 is correct
+         * for either sign of the error value.
+         * Note: errorptr points to *previous* column's array entry.
+         */
+        cur = RIGHT_SHIFT(cur + errorptr[dir] + 8, 4);
+        /* Form pixel value + error, and range-limit to 0..MAXJSAMPLE.
+         * The maximum error is +- MAXJSAMPLE; this sets the required size
+         * of the range_limit array.
+         */
+        cur += GETJSAMPLE(*input_ptr);
+        cur = GETJSAMPLE(range_limit[cur]);
+        /* Select output value, accumulate into output code for this pixel */
+        pixcode = GETJSAMPLE(colorindex_ci[cur]);
+        *output_ptr += (JSAMPLE) pixcode;
+        /* Compute actual representation error at this pixel */
+        /* Note: we can do this even though we don't have the final */
+        /* pixel code, because the colormap is orthogonal. */
+        cur -= GETJSAMPLE(colormap_ci[pixcode]);
+        /* Compute error fractions to be propagated to adjacent pixels.
+         * Add these into the running sums, and simultaneously shift the
+         * next-line error sums left by 1 column.
+         */
+        bnexterr = cur;
+        delta = cur * 2;
+        cur += delta;           /* form error * 3 */
+        errorptr[0] = (FSERROR) (bpreverr + cur);
+        cur += delta;           /* form error * 5 */
+        bpreverr = belowerr + cur;
+        belowerr = bnexterr;
+        cur += delta;           /* form error * 7 */
+        /* At this point cur contains the 7/16 error value to be propagated
+         * to the next pixel on the current line, and all the errors for the
+         * next line have been shifted over. We are therefore ready to move on.
+         */
+        input_ptr += dirnc;     /* advance input ptr to next column */
+        output_ptr += dir;      /* advance output ptr to next column */
+        errorptr += dir;        /* advance errorptr to current column */
+      }
+      /* Post-loop cleanup: we must unload the final error value into the
+       * final fserrors[] entry.  Note we need not unload belowerr because
+       * it is for the dummy column before or after the actual array.
+       */
+      errorptr[0] = (FSERROR) bpreverr; /* unload prev err into array */
+    }
+    cquantize->on_odd_row = (cquantize->on_odd_row ? FALSE : TRUE);
+  }
+}
+
+
+/*
+ * Allocate workspace for Floyd-Steinberg errors.
+ */
+
+LOCAL(void)
+alloc_fs_workspace (j_decompress_ptr cinfo)
+{
+  my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+  size_t arraysize;
+  int i;
+
+  arraysize = (size_t) ((cinfo->output_width + 2) * SIZEOF(FSERROR));
+  for (i = 0; i < cinfo->out_color_components; i++) {
+    cquantize->fserrors[i] = (FSERRPTR)
+      (*cinfo->mem->alloc_large)((j_common_ptr) cinfo, JPOOL_IMAGE, arraysize);
+  }
+}
+
+
+/*
+ * Initialize for one-pass color quantization.
+ */
+
+METHODDEF(void)
+start_pass_1_quant (j_decompress_ptr cinfo, boolean is_pre_scan)
+{
+  my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+  size_t arraysize;
+  int i;
+
+  /* Install my colormap. */
+  cinfo->colormap = cquantize->sv_colormap;
+  cinfo->actual_number_of_colors = cquantize->sv_actual;
+
+  /* Initialize for desired dithering mode. */
+  switch (cinfo->dither_mode) {
+  case JDITHER_NONE:
+    if (cinfo->out_color_components == 3)
+      cquantize->pub.color_quantize = color_quantize3;
+    else
+      cquantize->pub.color_quantize = color_quantize;
+    break;
+  case JDITHER_ORDERED:
+    if (cinfo->out_color_components == 3)
+      cquantize->pub.color_quantize = quantize3_ord_dither;
+    else
+      cquantize->pub.color_quantize = quantize_ord_dither;
+    cquantize->row_index = 0;   /* initialize state for ordered dither */
+    /* If user changed to ordered dither from another mode,
+     * we must recreate the color index table with padding.
+     * This will cost extra space, but probably isn't very likely.
+     */
+    if (! cquantize->is_padded)
+      create_colorindex(cinfo);
+    /* Create ordered-dither tables if we didn't already. */
+    if (cquantize->odither[0] == NULL)
+      create_odither_tables(cinfo);
+    break;
+  case JDITHER_FS:
+    cquantize->pub.color_quantize = quantize_fs_dither;
+    cquantize->on_odd_row = FALSE; /* initialize state for F-S dither */
+    /* Allocate Floyd-Steinberg workspace if didn't already. */
+    if (cquantize->fserrors[0] == NULL)
+      alloc_fs_workspace(cinfo);
+    /* Initialize the propagated errors to zero. */
+    arraysize = (size_t) ((cinfo->output_width + 2) * SIZEOF(FSERROR));
+    for (i = 0; i < cinfo->out_color_components; i++)
+      FMEMZERO((void FAR *) cquantize->fserrors[i], arraysize);
+    break;
+  default:
+    ERREXIT(cinfo, JERR_NOT_COMPILED);
+    break;
+  }
+}
+
+
+/*
+ * Finish up at the end of the pass.
+ */
+
+METHODDEF(void)
+finish_pass_1_quant (j_decompress_ptr cinfo)
+{
+  /* no work in 1-pass case */
+}
+
+
+/*
+ * Switch to a new external colormap between output passes.
+ * Shouldn't get to this module!
+ */
+
+METHODDEF(void)
+new_color_map_1_quant (j_decompress_ptr cinfo)
+{
+  ERREXIT(cinfo, JERR_MODE_CHANGE);
+}
+
+
+/*
+ * Module initialization routine for 1-pass color quantization.
+ */
+
+GLOBAL(void)
+jinit_1pass_quantizer (j_decompress_ptr cinfo)
+{
+  my_cquantize_ptr cquantize;
+
+  cquantize = (my_cquantize_ptr)
+    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+                                SIZEOF(my_cquantizer));
+  cinfo->cquantize = (struct jpeg_color_quantizer *) cquantize;
+  cquantize->pub.start_pass = start_pass_1_quant;
+  cquantize->pub.finish_pass = finish_pass_1_quant;
+  cquantize->pub.new_color_map = new_color_map_1_quant;
+  cquantize->fserrors[0] = NULL; /* Flag FS workspace not allocated */
+  cquantize->odither[0] = NULL; /* Also flag odither arrays not allocated */
+
+  /* Make sure my internal arrays won't overflow */
+  if (cinfo->out_color_components > MAX_Q_COMPS)
+    ERREXIT1(cinfo, JERR_QUANT_COMPONENTS, MAX_Q_COMPS);
+  /* Make sure colormap indexes can be represented by JSAMPLEs */
+  if (cinfo->desired_number_of_colors > (MAXJSAMPLE+1))
+    ERREXIT1(cinfo, JERR_QUANT_MANY_COLORS, MAXJSAMPLE+1);
+
+  /* Create the colormap and color index table. */
+  create_colormap(cinfo);
+  create_colorindex(cinfo);
+
+  /* Allocate Floyd-Steinberg workspace now if requested.
+   * We do this now since it is FAR storage and may affect the memory
+   * manager's space calculations.  If the user changes to FS dither
+   * mode in a later pass, we will allocate the space then, and will
+   * possibly overrun the max_memory_to_use setting.
+   */
+  if (cinfo->dither_mode == JDITHER_FS)
+    alloc_fs_workspace(cinfo);
+}
+
+#endif /* QUANT_1PASS_SUPPORTED */