[400] | 1 | /* |
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| 2 | * scode.c: decode scode captchas |
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| 3 | * $Id: scode.c 409 2005-01-04 12:11:05Z sam $ |
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| 4 | * |
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| 5 | * Copyright: (c) 2004 Sam Hocevar <sam@zoy.org> |
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| 6 | * This program is free software; you can redistribute it and/or |
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| 7 | * modify it under the terms of the Do What The Fuck You Want To |
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| 8 | * Public License as published by Banlu Kemiyatorn. See |
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| 9 | * http://sam.zoy.org/projects/COPYING.WTFPL for more details. |
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| 10 | */ |
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| 11 | |
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| 12 | #include <stdio.h> |
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| 13 | #include <stdlib.h> |
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| 14 | #include <string.h> |
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| 15 | |
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| 16 | #include "config.h" |
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| 17 | #include "common.h" |
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| 18 | |
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| 19 | static char find_glyph(struct image *img, int xmin, int xmax); |
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| 20 | |
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| 21 | /* Main function */ |
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| 22 | char *decode_scode(struct image *img) |
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| 23 | { |
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| 24 | char *result; |
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| 25 | int stats[256]; |
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| 26 | int x, y, i, incell = 0, cur = 0, xmin = 0; |
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| 27 | int r, g, b; |
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| 28 | struct image *tmp1; |
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| 29 | |
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| 30 | /* allocate enough place */ |
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| 31 | result = malloc(1024 * sizeof(char)); |
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| 32 | |
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[401] | 33 | /* Detect background: first and last 3 lines */ |
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[400] | 34 | for(i = 0; i < 256; i++) |
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| 35 | stats[i] = 0; |
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| 36 | |
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| 37 | for(y = 0; y < 3; y++) |
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| 38 | for(x = 0; x < img->width; x++) |
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| 39 | { |
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| 40 | getpixel(img, x, y, &r, &g, &b); |
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| 41 | stats[r]++; |
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[401] | 42 | getpixel(img, x, img->width - 1 - y, &r, &g, &b); |
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| 43 | stats[r]++; |
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[400] | 44 | } |
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| 45 | |
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| 46 | /* Set non-background colours to 0 */ |
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| 47 | tmp1 = image_new(img->width, img->height); |
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| 48 | |
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| 49 | for(y = 0; y < img->height; y++) |
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| 50 | for(x = 0; x < img->width; x++) |
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| 51 | { |
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| 52 | getpixel(img, x, y, &r, &g, &b); |
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| 53 | if(stats[r]) |
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| 54 | setpixel(tmp1, x, y, 255, 255, 255); |
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| 55 | else |
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| 56 | setpixel(tmp1, x, y, 0, 0, 0); |
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| 57 | } |
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| 58 | |
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| 59 | /* Decode glyphs */ |
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| 60 | for(x = 0; x < img->width; x++) |
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| 61 | { |
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| 62 | int found = 0; |
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| 63 | for(y = 0; y < img->height; y++) |
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| 64 | { |
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| 65 | getpixel(tmp1, x, y, &r, &g, &b); |
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| 66 | if(!r) |
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| 67 | { |
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| 68 | found = 1; |
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| 69 | break; |
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| 70 | } |
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| 71 | } |
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| 72 | if(found && !incell) |
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| 73 | { |
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| 74 | incell = 1; |
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| 75 | xmin = x; |
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| 76 | } |
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| 77 | else if(!found && incell) |
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| 78 | { |
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| 79 | incell = 0; |
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| 80 | /* Find glyph */ |
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| 81 | result[cur++] = find_glyph(tmp1, xmin, x); |
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| 82 | } |
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| 83 | } |
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| 84 | |
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| 85 | image_free(tmp1); |
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[409] | 86 | result[cur] = '\0'; |
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[400] | 87 | |
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| 88 | return result; |
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| 89 | } |
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| 90 | |
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| 91 | static char find_glyph(struct image *img, int xmin, int xmax) |
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| 92 | { |
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| 93 | int ymin = -1, ymax = -1; |
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| 94 | int x, y, count = 0; |
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| 95 | int r, g, b; |
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| 96 | |
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| 97 | /* Compute vertical bounds of glyph */ |
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| 98 | for(y = 0; y < img->height; y++) |
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| 99 | { |
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| 100 | int found = 0; |
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| 101 | for(x = xmin; x < xmax; x++) |
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| 102 | { |
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| 103 | getpixel(img, x, y, &r, &g, &b); |
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| 104 | if(!r) |
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| 105 | { |
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| 106 | found = 1; |
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| 107 | break; |
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| 108 | } |
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| 109 | } |
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| 110 | if(found) |
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| 111 | { |
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| 112 | if(ymin == -1) |
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| 113 | ymin = y; |
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| 114 | else |
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| 115 | ymax = y + 1; |
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| 116 | } |
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| 117 | } |
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| 118 | |
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| 119 | for(x = xmin; x < xmax; x++) |
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| 120 | { |
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| 121 | for(y = ymin; y < ymax; y++) |
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| 122 | { |
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| 123 | getpixel(img, x, y, &r, &g, &b); |
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| 124 | if(!r) |
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[401] | 125 | count += 5 * (y - ymin) ^ 3 * (x - xmin); |
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| 126 | //count += y - ymin; |
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[400] | 127 | } |
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| 128 | } |
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| 129 | |
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| 130 | switch(count) |
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| 131 | { |
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[401] | 132 | /* Scode font */ |
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| 133 | case 778: return '0'; |
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| 134 | case 621: return '1'; |
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| 135 | case 854: return '2'; |
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| 136 | case 784: return '3'; |
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| 137 | case 766: return '4'; |
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| 138 | case 771: return '5'; |
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| 139 | case 976: return '6'; |
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| 140 | case 585: return '7'; |
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| 141 | case 980: return '8'; |
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| 142 | case 896: return '9'; |
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| 143 | /* Small font */ |
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| 144 | case 584: return '0'; |
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| 145 | case 454: return '1'; |
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| 146 | case 517: return '2'; |
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| 147 | case 447: return '3'; |
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| 148 | case 469: return '4'; |
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| 149 | case 472: return '5'; |
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| 150 | case 564: return '6'; |
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| 151 | case 298: return '7'; |
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| 152 | case 560: return '8'; |
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| 153 | case 536: return '9'; |
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| 154 | /* Thin font */ |
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| 155 | case 438: return '0'; |
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| 156 | case 405: return '1'; |
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| 157 | case 485: return '2'; |
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| 158 | case 486: return '3'; |
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| 159 | case 413: return '4'; |
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| 160 | case 509: return '5'; |
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| 161 | case 582: return '6'; |
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| 162 | case 242: return '7'; |
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| 163 | case 579: return '8'; |
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| 164 | case 440: return '9'; |
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| 165 | #if 0 |
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[400] | 166 | case 162: return '0'; |
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| 167 | case 131: return '1'; |
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| 168 | case 150: return '2'; |
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| 169 | case 139: return '3'; |
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| 170 | case 155: return '4'; |
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| 171 | case 159: return '5'; |
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| 172 | case 181: return '6'; |
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| 173 | case 90: return '7'; |
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| 174 | case 180: return '8'; |
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| 175 | case 170: return '9'; |
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[401] | 176 | #endif |
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[400] | 177 | default: |
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| 178 | dprintf("don't know about checksum %i\n", count); |
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| 179 | return '?'; |
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| 180 | } |
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| 181 | } |
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| 182 | |
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