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