compiler/libjpeg/test/rdcolmap.c

   1 /*
   2     $Id$
   3 */
   4
   5 /*
   6  * rdcolmap.c
   7  *
   8  * Copyright (C) 1994-1996, Thomas G. Lane.
   9  * This file is part of the Independent JPEG Group's software.
  10  * For conditions of distribution and use, see the accompanying README file.
  11  *
  12  * This file implements djpeg's "-map file" switch.  It reads a source image
  13  * and constructs a colormap to be supplied to the JPEG decompressor.
  14  *
  15  * Currently, these file formats are supported for the map file:
  16  *   GIF: the contents of the GIF's global colormap are used.
  17  *   PPM (either text or raw flavor): the entire file is read and
  18  *      each unique pixel value is entered in the map.
  19  * Note that reading a large PPM file will be horrendously slow.
  20  * Typically, a PPM-format map file should contain just one pixel
  21  * of each desired color.  Such a file can be extracted from an
  22  * ordinary image PPM file with ppmtomap(1).
  23  *
  24  * Rescaling a PPM that has a maxval unequal to MAXJSAMPLE is not
  25  * currently implemented.
  26  */
  27
  28 #include "cdjpeg.h"             /* Common decls for cjpeg/djpeg applications */
  29
  30 #ifdef QUANT_2PASS_SUPPORTED    /* otherwise can't quantize to supplied map */
  31
  32 /* Portions of this code are based on the PBMPLUS library, which is:
  33 **
  34 ** Copyright (C) 1988 by Jef Poskanzer.
  35 **
  36 ** Permission to use, copy, modify, and distribute this software and its
  37 ** documentation for any purpose and without fee is hereby granted, provided
  38 ** that the above copyright notice appear in all copies and that both that
  39 ** copyright notice and this permission notice appear in supporting
  40 ** documentation.  This software is provided "as is" without express or
  41 ** implied warranty.
  42 */
  43
  44
  45 /*
  46  * Add a (potentially) new color to the color map.
  47  */
  48
  49 LOCAL(void)
  50 add_map_entry (j_decompress_ptr cinfo, int R, int G, int B)
  51 {
  52   JSAMPROW colormap0 = cinfo->colormap[0];
  53   JSAMPROW colormap1 = cinfo->colormap[1];
  54   JSAMPROW colormap2 = cinfo->colormap[2];
  55   int ncolors = cinfo->actual_number_of_colors;
  56   int index;
  57
  58   /* Check for duplicate color. */
  59   for (index = 0; index < ncolors; index++) {
  60     if (GETJSAMPLE(colormap0[index]) == R &&
  61         GETJSAMPLE(colormap1[index]) == G &&
  62         GETJSAMPLE(colormap2[index]) == B)
  63       return;                   /* color is already in map */
  64   }
  65
  66   /* Check for map overflow. */
  67   if (ncolors >= (MAXJSAMPLE+1))
  68     ERREXIT1(cinfo, JERR_QUANT_MANY_COLORS, (MAXJSAMPLE+1));
  69
  70   /* OK, add color to map. */
  71   colormap0[ncolors] = (JSAMPLE) R;
  72   colormap1[ncolors] = (JSAMPLE) G;
  73   colormap2[ncolors] = (JSAMPLE) B;
  74   cinfo->actual_number_of_colors++;
  75 }
  76
  77
  78 /*
  79  * Extract color map from a GIF file.
  80  */
  81
  82 LOCAL(void)
  83 read_gif_map (j_decompress_ptr cinfo, FILE * infile)
  84 {
  85   int header[13];
  86   int i, colormaplen;
  87   int R, G, B;
  88
  89   /* Initial 'G' has already been read by read_color_map */
  90   /* Read the rest of the GIF header and logical screen descriptor */
  91   for (i = 1; i < 13; i++) {
  92     if ((header[i] = getc(infile)) == EOF)
  93       ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
  94   }
  95
  96   /* Verify GIF Header */
  97   if (header[1] != 'I' || header[2] != 'F')
  98     ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
  99
 100   /* There must be a global color map. */
 101   if ((header[10] & 0x80) == 0)
 102     ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
 103
 104   /* OK, fetch it. */
 105   colormaplen = 2 << (header[10] & 0x07);
 106
 107   for (i = 0; i < colormaplen; i++) {
 108     R = getc(infile);
 109     G = getc(infile);
 110     B = getc(infile);
 111     if (R == EOF || G == EOF || B == EOF)
 112       ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
 113     add_map_entry(cinfo,
 114                   R << (BITS_IN_JSAMPLE-8),
 115                   G << (BITS_IN_JSAMPLE-8),
 116                   B << (BITS_IN_JSAMPLE-8));
 117   }
 118 }
 119
 120
 121 /* Support routines for reading PPM */
 122
 123
 124 LOCAL(int)
 125 pbm_getc (FILE * infile)
 126 /* Read next char, skipping over any comments */
 127 /* A comment/newline sequence is returned as a newline */
 128 {
 129   register int ch;
 130
 131   ch = getc(infile);
 132   if (ch == '#') {
 133     do {
 134       ch = getc(infile);
 135     } while (ch != '\n' && ch != EOF);
 136   }
 137   return ch;
 138 }
 139
 140
 141 LOCAL(unsigned int)
 142 read_pbm_integer (j_decompress_ptr cinfo, FILE * infile)
 143 /* Read an unsigned decimal integer from the PPM file */
 144 /* Swallows one trailing character after the integer */
 145 /* Note that on a 16-bit-int machine, only values up to 64k can be read. */
 146 /* This should not be a problem in practice. */
 147 {
 148   register int ch;
 149   register unsigned int val;
 150
 151   /* Skip any leading whitespace */
 152   do {
 153     ch = pbm_getc(infile);
 154     if (ch == EOF)
 155       ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
 156   } while (ch == ' ' || ch == '\t' || ch == '\n' || ch == '\r');
 157
 158   if (ch < '0' || ch > '9')
 159     ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
 160
 161   val = ch - '0';
 162   while ((ch = pbm_getc(infile)) >= '0' && ch <= '9') {
 163     val *= 10;
 164     val += ch - '0';
 165   }
 166   return val;
 167 }
 168
 169
 170 /*
 171  * Extract color map from a PPM file.
 172  */
 173
 174 LOCAL(void)
 175 read_ppm_map (j_decompress_ptr cinfo, FILE * infile)
 176 {
 177   int c;
 178   unsigned int w, h, maxval, row, col;
 179   int R, G, B;
 180
 181   /* Initial 'P' has already been read by read_color_map */
 182   c = getc(infile);             /* save format discriminator for a sec */
 183
 184   /* while we fetch the remaining header info */
 185   w = read_pbm_integer(cinfo, infile);
 186   h = read_pbm_integer(cinfo, infile);
 187   maxval = read_pbm_integer(cinfo, infile);
 188
 189   if (w <= 0 || h <= 0 || maxval <= 0) /* error check */
 190     ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
 191
 192   /* For now, we don't support rescaling from an unusual maxval. */
 193   if (maxval != (unsigned int) MAXJSAMPLE)
 194     ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
 195
 196   switch (c) {
 197   case '3':                     /* it's a text-format PPM file */
 198     for (row = 0; row < h; row++) {
 199       for (col = 0; col < w; col++) {
 200         R = read_pbm_integer(cinfo, infile);
 201         G = read_pbm_integer(cinfo, infile);
 202         B = read_pbm_integer(cinfo, infile);
 203         add_map_entry(cinfo, R, G, B);
 204       }
 205     }
 206     break;
 207
 208   case '6':                     /* it's a raw-format PPM file */
 209     for (row = 0; row < h; row++) {
 210       for (col = 0; col < w; col++) {
 211         R = getc(infile);
 212         G = getc(infile);
 213         B = getc(infile);
 214         if (R == EOF || G == EOF || B == EOF)
 215           ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
 216         add_map_entry(cinfo, R, G, B);
 217       }
 218     }
 219     break;
 220
 221   default:
 222     ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
 223     break;
 224   }
 225 }
 226
 227
 228 /*
 229  * Main entry point from djpeg.c.
 230  *  Input: opened input file (from file name argument on command line).
 231  *  Output: colormap and actual_number_of_colors fields are set in cinfo.
 232  */
 233
 234 JGLOBAL(void)
 235 read_color_map (j_decompress_ptr cinfo, FILE * infile)
 236 {
 237   /* Allocate space for a color map of maximum supported size. */
 238   cinfo->colormap = (*cinfo->mem->alloc_sarray)
 239     ((j_common_ptr) cinfo, JPOOL_IMAGE,
 240      (JDIMENSION) (MAXJSAMPLE+1), (JDIMENSION) 3);
 241   cinfo->actual_number_of_colors = 0; /* initialize map to empty */
 242
 243   /* Read first byte to determine file format */
 244   switch (getc(infile)) {
 245   case 'G':
 246     read_gif_map(cinfo, infile);
 247     break;
 248   case 'P':
 249     read_ppm_map(cinfo, infile);
 250     break;
 251   default:
 252     ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
 253     break;
 254   }
 255 }
 256
 257 #endif /* QUANT_2PASS_SUPPORTED */