source: trunk/libjpeg/rdcolmap.c @ 15

Last change on this file since 15 was 15, checked in by Eugene Romanenko, 16 years ago

needed libs update

File size: 6.9 KB
Line 
1/*
2 * rdcolmap.c
3 *
4 * Copyright (C) 1994-1996, Thomas G. Lane.
5 * This file is part of the Independent JPEG Group's software.
6 * For conditions of distribution and use, see the accompanying README file.
7 *
8 * This file implements djpeg's "-map file" switch.  It reads a source image
9 * and constructs a colormap to be supplied to the JPEG decompressor.
10 *
11 * Currently, these file formats are supported for the map file:
12 *   GIF: the contents of the GIF's global colormap are used.
13 *   PPM (either text or raw flavor): the entire file is read and
14 *      each unique pixel value is entered in the map.
15 * Note that reading a large PPM file will be horrendously slow.
16 * Typically, a PPM-format map file should contain just one pixel
17 * of each desired color.  Such a file can be extracted from an
18 * ordinary image PPM file with ppmtomap(1).
19 *
20 * Rescaling a PPM that has a maxval unequal to MAXJSAMPLE is not
21 * currently implemented.
22 */
23
24#include "cdjpeg.h"             /* Common decls for cjpeg/djpeg applications */
25
26#ifdef QUANT_2PASS_SUPPORTED    /* otherwise can't quantize to supplied map */
27
28/* Portions of this code are based on the PBMPLUS library, which is:
29**
30** Copyright (C) 1988 by Jef Poskanzer.
31**
32** Permission to use, copy, modify, and distribute this software and its
33** documentation for any purpose and without fee is hereby granted, provided
34** that the above copyright notice appear in all copies and that both that
35** copyright notice and this permission notice appear in supporting
36** documentation.  This software is provided "as is" without express or
37** implied warranty.
38*/
39
40
41/*
42 * Add a (potentially) new color to the color map.
43 */
44
45LOCAL(void)
46add_map_entry (j_decompress_ptr cinfo, int R, int G, int B)
47{
48  JSAMPROW colormap0 = cinfo->colormap[0];
49  JSAMPROW colormap1 = cinfo->colormap[1];
50  JSAMPROW colormap2 = cinfo->colormap[2];
51  int ncolors = cinfo->actual_number_of_colors;
52  int index;
53
54  /* Check for duplicate color. */
55  for (index = 0; index < ncolors; index++) {
56    if (GETJSAMPLE(colormap0[index]) == R &&
57        GETJSAMPLE(colormap1[index]) == G &&
58        GETJSAMPLE(colormap2[index]) == B)
59      return;                   /* color is already in map */
60  }
61
62  /* Check for map overflow. */
63  if (ncolors >= (MAXJSAMPLE+1))
64    ERREXIT1(cinfo, JERR_QUANT_MANY_COLORS, (MAXJSAMPLE+1));
65
66  /* OK, add color to map. */
67  colormap0[ncolors] = (JSAMPLE) R;
68  colormap1[ncolors] = (JSAMPLE) G;
69  colormap2[ncolors] = (JSAMPLE) B;
70  cinfo->actual_number_of_colors++;
71}
72
73
74/*
75 * Extract color map from a GIF file.
76 */
77
78LOCAL(void)
79read_gif_map (j_decompress_ptr cinfo, FILE * infile)
80{
81  int header[13];
82  int i, colormaplen;
83  int R, G, B;
84
85  /* Initial 'G' has already been read by read_color_map */
86  /* Read the rest of the GIF header and logical screen descriptor */
87  for (i = 1; i < 13; i++) {
88    if ((header[i] = getc(infile)) == EOF)
89      ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
90  }
91
92  /* Verify GIF Header */
93  if (header[1] != 'I' || header[2] != 'F')
94    ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
95
96  /* There must be a global color map. */
97  if ((header[10] & 0x80) == 0)
98    ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
99
100  /* OK, fetch it. */
101  colormaplen = 2 << (header[10] & 0x07);
102
103  for (i = 0; i < colormaplen; i++) {
104    R = getc(infile);
105    G = getc(infile);
106    B = getc(infile);
107    if (R == EOF || G == EOF || B == EOF)
108      ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
109    add_map_entry(cinfo,
110                  R << (BITS_IN_JSAMPLE-8),
111                  G << (BITS_IN_JSAMPLE-8),
112                  B << (BITS_IN_JSAMPLE-8));
113  }
114}
115
116
117/* Support routines for reading PPM */
118
119
120LOCAL(int)
121pbm_getc (FILE * infile)
122/* Read next char, skipping over any comments */
123/* A comment/newline sequence is returned as a newline */
124{
125  register int ch;
126 
127  ch = getc(infile);
128  if (ch == '#') {
129    do {
130      ch = getc(infile);
131    } while (ch != '\n' && ch != EOF);
132  }
133  return ch;
134}
135
136
137LOCAL(unsigned int)
138read_pbm_integer (j_decompress_ptr cinfo, FILE * infile)
139/* Read an unsigned decimal integer from the PPM file */
140/* Swallows one trailing character after the integer */
141/* Note that on a 16-bit-int machine, only values up to 64k can be read. */
142/* This should not be a problem in practice. */
143{
144  register int ch;
145  register unsigned int val;
146 
147  /* Skip any leading whitespace */
148  do {
149    ch = pbm_getc(infile);
150    if (ch == EOF)
151      ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
152  } while (ch == ' ' || ch == '\t' || ch == '\n' || ch == '\r');
153 
154  if (ch < '0' || ch > '9')
155    ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
156 
157  val = ch - '0';
158  while ((ch = pbm_getc(infile)) >= '0' && ch <= '9') {
159    val *= 10;
160    val += ch - '0';
161  }
162  return val;
163}
164
165
166/*
167 * Extract color map from a PPM file.
168 */
169
170LOCAL(void)
171read_ppm_map (j_decompress_ptr cinfo, FILE * infile)
172{
173  int c;
174  unsigned int w, h, maxval, row, col;
175  int R, G, B;
176
177  /* Initial 'P' has already been read by read_color_map */
178  c = getc(infile);             /* save format discriminator for a sec */
179
180  /* while we fetch the remaining header info */
181  w = read_pbm_integer(cinfo, infile);
182  h = read_pbm_integer(cinfo, infile);
183  maxval = read_pbm_integer(cinfo, infile);
184
185  if (w <= 0 || h <= 0 || maxval <= 0) /* error check */
186    ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
187
188  /* For now, we don't support rescaling from an unusual maxval. */
189  if (maxval != (unsigned int) MAXJSAMPLE)
190    ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
191
192  switch (c) {
193  case '3':                     /* it's a text-format PPM file */
194    for (row = 0; row < h; row++) {
195      for (col = 0; col < w; col++) {
196        R = read_pbm_integer(cinfo, infile);
197        G = read_pbm_integer(cinfo, infile);
198        B = read_pbm_integer(cinfo, infile);
199        add_map_entry(cinfo, R, G, B);
200      }
201    }
202    break;
203
204  case '6':                     /* it's a raw-format PPM file */
205    for (row = 0; row < h; row++) {
206      for (col = 0; col < w; col++) {
207        R = getc(infile);
208        G = getc(infile);
209        B = getc(infile);
210        if (R == EOF || G == EOF || B == EOF)
211          ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
212        add_map_entry(cinfo, R, G, B);
213      }
214    }
215    break;
216
217  default:
218    ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
219    break;
220  }
221}
222
223
224/*
225 * Main entry point from djpeg.c.
226 *  Input: opened input file (from file name argument on command line).
227 *  Output: colormap and actual_number_of_colors fields are set in cinfo.
228 */
229
230GLOBAL(void)
231read_color_map (j_decompress_ptr cinfo, FILE * infile)
232{
233  /* Allocate space for a color map of maximum supported size. */
234  cinfo->colormap = (*cinfo->mem->alloc_sarray)
235    ((j_common_ptr) cinfo, JPOOL_IMAGE,
236     (JDIMENSION) (MAXJSAMPLE+1), (JDIMENSION) 3);
237  cinfo->actual_number_of_colors = 0; /* initialize map to empty */
238
239  /* Read first byte to determine file format */
240  switch (getc(infile)) {
241  case 'G':
242    read_gif_map(cinfo, infile);
243    break;
244  case 'P':
245    read_ppm_map(cinfo, infile);
246    break;
247  default:
248    ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
249    break;
250  }
251}
252
253#endif /* QUANT_2PASS_SUPPORTED */
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