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  1. /* cairo - a vector graphics library with display and print output
  2.  *
  3.  * Copyright © 2008 Adrian Johnson
  4.  *
  5.  * This library is free software; you can redistribute it and/or
  6.  * modify it either under the terms of the GNU Lesser General Public
  7.  * License version 2.1 as published by the Free Software Foundation
  8.  * (the "LGPL") or, at your option, under the terms of the Mozilla
  9.  * Public License Version 1.1 (the "MPL"). If you do not alter this
  10.  * notice, a recipient may use your version of this file under either
  11.  * the MPL or the LGPL.
  12.  *
  13.  * You should have received a copy of the LGPL along with this library
  14.  * in the file COPYING-LGPL-2.1; if not, write to the Free Software
  15.  * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
  16.  * You should have received a copy of the MPL along with this library
  17.  * in the file COPYING-MPL-1.1
  18.  *
  19.  * The contents of this file are subject to the Mozilla Public License
  20.  * Version 1.1 (the "License"); you may not use this file except in
  21.  * compliance with the License. You may obtain a copy of the License at
  22.  * http://www.mozilla.org/MPL/
  23.  *
  24.  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
  25.  * OF ANY KIND, either express or implied. See the LGPL or the MPL for
  26.  * the specific language governing rights and limitations.
  27.  *
  28.  * The Original Code is the cairo graphics library.
  29.  *
  30.  * The Initial Developer of the Original Code is Adrian Johnson.
  31.  *
  32.  * Contributor(s):
  33.  *      Adrian Johnson <ajohnson@redneon.com>
  34.  */
  35.  
  36. #include "cairoint.h"
  37. #include "cairo-image-info-private.h"
  38.  
  39. static uint32_t
  40. _get_be32 (const unsigned char *p)
  41. {
  42.     return p[0] << 24 | p[1] << 16 | p[2] << 8 | p[3];
  43. }
  44.  
  45. /* JPEG (image/jpeg)
  46.  *
  47.  * http://www.w3.org/Graphics/JPEG/itu-t81.pdf
  48.  */
  49.  
  50. /* Markers with no parameters. All other markers are followed by a two
  51.  * byte length of the parameters. */
  52. #define TEM       0x01
  53. #define RST_begin 0xd0
  54. #define RST_end   0xd7
  55. #define SOI       0xd8
  56. #define EOI       0xd9
  57.  
  58. /* Start of frame markers. */
  59. #define SOF0  0xc0
  60. #define SOF1  0xc1
  61. #define SOF2  0xc2
  62. #define SOF3  0xc3
  63. #define SOF5  0xc5
  64. #define SOF6  0xc6
  65. #define SOF7  0xc7
  66. #define SOF9  0xc9
  67. #define SOF10 0xca
  68. #define SOF11 0xcb
  69. #define SOF13 0xcd
  70. #define SOF14 0xce
  71. #define SOF15 0xcf
  72.  
  73. static const unsigned char *
  74. _jpeg_skip_segment (const unsigned char *p)
  75. {
  76.     int len;
  77.  
  78.     p++;
  79.     len = (p[0] << 8) | p[1];
  80.  
  81.     return p + len;
  82. }
  83.  
  84. static void
  85. _jpeg_extract_info (cairo_image_info_t *info, const unsigned char *p)
  86. {
  87.     info->width = (p[6] << 8) + p[7];
  88.     info->height = (p[4] << 8) + p[5];
  89.     info->num_components = p[8];
  90.     info->bits_per_component = p[3];
  91. }
  92.  
  93. cairo_int_status_t
  94. _cairo_image_info_get_jpeg_info (cairo_image_info_t     *info,
  95.                                  const unsigned char    *data,
  96.                                  long                    length)
  97. {
  98.     const unsigned char *p = data;
  99.  
  100.     while (p + 1 < data + length) {
  101.         if (*p != 0xff)
  102.             return CAIRO_INT_STATUS_UNSUPPORTED;
  103.         p++;
  104.  
  105.         switch (*p) {
  106.             /* skip fill bytes */
  107.         case 0xff:
  108.             p++;
  109.             break;
  110.  
  111.         case TEM:
  112.         case SOI:
  113.         case EOI:
  114.             p++;
  115.             break;
  116.  
  117.         case SOF0:
  118.         case SOF1:
  119.         case SOF2:
  120.         case SOF3:
  121.         case SOF5:
  122.         case SOF6:
  123.         case SOF7:
  124.         case SOF9:
  125.         case SOF10:
  126.         case SOF11:
  127.         case SOF13:
  128.         case SOF14:
  129.         case SOF15:
  130.             /* Start of frame found. Extract the image parameters. */
  131.             if (p + 8 > data + length)
  132.                 return CAIRO_INT_STATUS_UNSUPPORTED;
  133.  
  134.             _jpeg_extract_info (info, p);
  135.             return CAIRO_STATUS_SUCCESS;
  136.  
  137.         default:
  138.             if (*p >= RST_begin && *p <= RST_end) {
  139.                 p++;
  140.                 break;
  141.             }
  142.  
  143.             if (p + 2 > data + length)
  144.                 return CAIRO_INT_STATUS_UNSUPPORTED;
  145.  
  146.             p = _jpeg_skip_segment (p);
  147.             break;
  148.         }
  149.     }
  150.  
  151.     return CAIRO_STATUS_SUCCESS;
  152. }
  153.  
  154. /* JPEG 2000 (image/jp2)
  155.  *
  156.  * http://www.jpeg.org/public/15444-1annexi.pdf
  157.  */
  158.  
  159. #define JPX_FILETYPE 0x66747970
  160. #define JPX_JP2_HEADER 0x6A703268
  161. #define JPX_IMAGE_HEADER 0x69686472
  162.  
  163. static const unsigned char _jpx_signature[] = {
  164.     0x00, 0x00, 0x00, 0x0c, 0x6a, 0x50, 0x20, 0x20, 0x0d, 0x0a, 0x87, 0x0a
  165. };
  166.  
  167. static const unsigned char *
  168. _jpx_next_box (const unsigned char *p)
  169. {
  170.     return p + _get_be32 (p);
  171. }
  172.  
  173. static const unsigned char *
  174. _jpx_get_box_contents (const unsigned char *p)
  175. {
  176.     return p + 8;
  177. }
  178.  
  179. static cairo_bool_t
  180. _jpx_match_box (const unsigned char *p, const unsigned char *end, uint32_t type)
  181. {
  182.     uint32_t length;
  183.  
  184.     if (p + 8 < end) {
  185.         length = _get_be32 (p);
  186.         if (_get_be32 (p + 4) == type &&  p + length < end)
  187.             return TRUE;
  188.     }
  189.  
  190.     return FALSE;
  191. }
  192.  
  193. static const unsigned char *
  194. _jpx_find_box (const unsigned char *p, const unsigned char *end, uint32_t type)
  195. {
  196.     while (p < end) {
  197.         if (_jpx_match_box (p, end, type))
  198.             return p;
  199.         p = _jpx_next_box (p);
  200.     }
  201.  
  202.     return NULL;
  203. }
  204.  
  205. static void
  206. _jpx_extract_info (const unsigned char *p, cairo_image_info_t *info)
  207. {
  208.     info->height = _get_be32 (p);
  209.     info->width = _get_be32 (p + 4);
  210.     info->num_components = (p[8] << 8) + p[9];
  211.     info->bits_per_component = p[10];
  212. }
  213.  
  214. cairo_int_status_t
  215. _cairo_image_info_get_jpx_info (cairo_image_info_t      *info,
  216.                                 const unsigned char     *data,
  217.                                 unsigned long            length)
  218. {
  219.     const unsigned char *p = data;
  220.     const unsigned char *end = data + length;
  221.  
  222.     /* First 12 bytes must be the JPEG 2000 signature box. */
  223.     if (length < ARRAY_LENGTH(_jpx_signature) ||
  224.         memcmp(p, _jpx_signature, ARRAY_LENGTH(_jpx_signature)) != 0)
  225.         return CAIRO_INT_STATUS_UNSUPPORTED;
  226.  
  227.     p += ARRAY_LENGTH(_jpx_signature);
  228.  
  229.     /* Next box must be a File Type Box */
  230.     if (! _jpx_match_box (p, end, JPX_FILETYPE))
  231.         return CAIRO_INT_STATUS_UNSUPPORTED;
  232.  
  233.     p = _jpx_next_box (p);
  234.  
  235.     /* Locate the JP2 header box. */
  236.     p = _jpx_find_box (p, end, JPX_JP2_HEADER);
  237.     if (!p)
  238.         return CAIRO_INT_STATUS_UNSUPPORTED;
  239.  
  240.     /* Step into the JP2 header box. First box must be the Image
  241.      * Header */
  242.     p = _jpx_get_box_contents (p);
  243.     if (! _jpx_match_box (p, end, JPX_IMAGE_HEADER))
  244.         return CAIRO_INT_STATUS_UNSUPPORTED;
  245.  
  246.     /* Get the image info */
  247.     p = _jpx_get_box_contents (p);
  248.     _jpx_extract_info (p, info);
  249.  
  250.     return CAIRO_STATUS_SUCCESS;
  251. }
  252.  
  253. /* PNG (image/png)
  254.  *
  255.  * http://www.w3.org/TR/2003/REC-PNG-20031110/
  256.  */
  257.  
  258. #define PNG_IHDR 0x49484452
  259.  
  260. static const unsigned char _png_magic[8] = { 137, 80, 78, 71, 13, 10, 26, 10 };
  261.  
  262. cairo_int_status_t
  263. _cairo_image_info_get_png_info (cairo_image_info_t     *info,
  264.                                const unsigned char     *data,
  265.                                unsigned long            length)
  266. {
  267.     const unsigned char *p = data;
  268.     const unsigned char *end = data + length;
  269.  
  270.     if (length < 8 || memcmp (data, _png_magic, 8) != 0)
  271.        return CAIRO_INT_STATUS_UNSUPPORTED;
  272.  
  273.     p += 8;
  274.  
  275.     /* The first chunk must be IDHR. IDHR has 13 bytes of data plus
  276.      * the 12 bytes of overhead for the chunk. */
  277.     if (p + 13 + 12 > end)
  278.        return CAIRO_INT_STATUS_UNSUPPORTED;
  279.  
  280.     p += 4;
  281.     if (_get_be32 (p) != PNG_IHDR)
  282.        return CAIRO_INT_STATUS_UNSUPPORTED;
  283.  
  284.     p += 4;
  285.     info->width = _get_be32 (p);
  286.     p += 4;
  287.     info->height = _get_be32 (p);
  288.  
  289.     return CAIRO_STATUS_SUCCESS;
  290. }
  291.