diff options
Diffstat (limited to 'src/cairo-image-info.c')
| -rw-r--r--[-rwxr-xr-x] | src/cairo-image-info.c | 157 |
1 files changed, 143 insertions, 14 deletions
diff --git a/src/cairo-image-info.c b/src/cairo-image-info.c index 4489698e8..26e7ae5af 100755..100644 --- a/src/cairo-image-info.c +++ b/src/cairo-image-info.c @@ -1,3 +1,4 @@ +/* -*- Mode: c; tab-width: 8; c-basic-offset: 4; indent-tabs-mode: t; -*- */ /* cairo - a vector graphics library with display and print output * * Copyright © 2008 Adrian Johnson @@ -38,12 +39,6 @@ #include "cairo-error-private.h" #include "cairo-image-info-private.h" -static uint32_t -_get_be32 (const unsigned char *p) -{ - return p[0] << 24 | p[1] << 16 | p[2] << 8 | p[3]; -} - /* JPEG (image/jpeg) * * http://www.w3.org/Graphics/JPEG/itu-t81.pdf @@ -169,7 +164,7 @@ static const unsigned char _jpx_signature[] = { static const unsigned char * _jpx_next_box (const unsigned char *p) { - return p + _get_be32 (p); + return p + get_unaligned_be32 (p); } static const unsigned char * @@ -184,8 +179,8 @@ _jpx_match_box (const unsigned char *p, const unsigned char *end, uint32_t type) uint32_t length; if (p + 8 < end) { - length = _get_be32 (p); - if (_get_be32 (p + 4) == type && p + length < end) + length = get_unaligned_be32 (p); + if (get_unaligned_be32 (p + 4) == type && p + length < end) return TRUE; } @@ -207,8 +202,8 @@ _jpx_find_box (const unsigned char *p, const unsigned char *end, uint32_t type) static void _jpx_extract_info (const unsigned char *p, cairo_image_info_t *info) { - info->height = _get_be32 (p); - info->width = _get_be32 (p + 4); + info->height = get_unaligned_be32 (p); + info->width = get_unaligned_be32 (p + 4); info->num_components = (p[8] << 8) + p[9]; info->bits_per_component = p[10]; } @@ -280,13 +275,147 @@ _cairo_image_info_get_png_info (cairo_image_info_t *info, return CAIRO_INT_STATUS_UNSUPPORTED; p += 4; - if (_get_be32 (p) != PNG_IHDR) + if (get_unaligned_be32 (p) != PNG_IHDR) return CAIRO_INT_STATUS_UNSUPPORTED; p += 4; - info->width = _get_be32 (p); + info->width = get_unaligned_be32 (p); p += 4; - info->height = _get_be32 (p); + info->height = get_unaligned_be32 (p); return CAIRO_STATUS_SUCCESS; } + +static const unsigned char * +_jbig2_find_data_end (const unsigned char *p, + const unsigned char *end, + int type) +{ + unsigned char end_seq[2]; + int mmr; + + /* Segments of type "Immediate generic region" may have an + * unspecified data length. The JBIG2 specification specifies the + * method to find the end of the data for these segments. */ + if (type == 36 || type == 38 || type == 39) { + if (p + 18 < end) { + mmr = p[17] & 0x01; + if (mmr) { + /* MMR encoding ends with 0x00, 0x00 */ + end_seq[0] = 0x00; + end_seq[1] = 0x00; + } else { + /* Template encoding ends with 0xff, 0xac */ + end_seq[0] = 0xff; + end_seq[1] = 0xac; + } + p += 18; + while (p < end) { + if (p[0] == end_seq[0] && p[1] == end_seq[1]) { + /* Skip the 2 terminating bytes and the 4 byte row count that follows. */ + p += 6; + if (p < end) + return p; + } + p++; + } + } + } + + return NULL; +} + +static const unsigned char * +_jbig2_get_next_segment (const unsigned char *p, + const unsigned char *end, + int *type, + const unsigned char **data, + unsigned long *data_len) +{ + unsigned long seg_num; + cairo_bool_t big_page_size; + int num_segs; + int ref_seg_bytes; + int referred_size; + + if (p + 6 >= end) + return NULL; + + seg_num = get_unaligned_be32 (p); + *type = p[4] & 0x3f; + big_page_size = (p[4] & 0x40) != 0; + p += 5; + + num_segs = p[0] >> 5; + if (num_segs == 7) { + num_segs = get_unaligned_be32 (p) & 0x1fffffff; + ref_seg_bytes = 4 + ((num_segs + 1)/8); + } else { + ref_seg_bytes = 1; + } + p += ref_seg_bytes; + + if (seg_num <= 256) + referred_size = 1; + else if (seg_num <= 65536) + referred_size = 2; + else + referred_size = 4; + + p += num_segs * referred_size; + p += big_page_size ? 4 : 1; + if (p + 4 >= end) + return NULL; + + *data_len = get_unaligned_be32 (p); + p += 4; + *data = p; + + if (*data_len == 0xffffffff) { + /* if data length is -1 we have to scan through the data to find the end */ + p = _jbig2_find_data_end (*data, end, *type); + if (!p || p >= end) + return NULL; + + *data_len = p - *data; + } else { + p += *data_len; + } + + if (p < end) + return p; + else + return NULL; +} + +static void +_jbig2_extract_info (cairo_image_info_t *info, const unsigned char *p) +{ + info->width = get_unaligned_be32 (p); + info->height = get_unaligned_be32 (p + 4); + info->num_components = 1; + info->bits_per_component = 1; +} + +cairo_int_status_t +_cairo_image_info_get_jbig2_info (cairo_image_info_t *info, + const unsigned char *data, + unsigned long length) +{ + const unsigned char *p = data; + const unsigned char *end = data + length; + int seg_type; + const unsigned char *seg_data; + unsigned long seg_data_len; + + while (p && p < end) { + p = _jbig2_get_next_segment (p, end, &seg_type, &seg_data, &seg_data_len); + if (p && seg_type == 48 && seg_data_len > 8) { + /* page information segment */ + _jbig2_extract_info (info, seg_data); + return CAIRO_STATUS_SUCCESS; + } + } + + return CAIRO_INT_STATUS_UNSUPPORTED; +} |