1 /*
2 * BMP parser
3 * Copyright (c) 2012 Paul B Mahol
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 /**
23 * @file
24 * BMP parser
25 */
26
27 #include "libavutil/bswap.h"
28 #include "libavutil/common.h"
29
30 #include "parser.h"
31
32 typedef struct BMPParseContext {
33 ParseContext pc;
34 uint32_t fsize;
35 uint32_t remaining_size;
36 } BMPParseContext;
37
bmp_parse(AVCodecParserContext * s,AVCodecContext * avctx,const uint8_t ** poutbuf,int * poutbuf_size,const uint8_t * buf,int buf_size)38 static int bmp_parse(AVCodecParserContext *s, AVCodecContext *avctx,
39 const uint8_t **poutbuf, int *poutbuf_size,
40 const uint8_t *buf, int buf_size)
41 {
42 BMPParseContext *bpc = s->priv_data;
43 uint64_t state = bpc->pc.state64;
44 int next = END_NOT_FOUND;
45 int i = 0;
46
47 *poutbuf_size = 0;
48 *poutbuf = NULL;
49
50 restart:
51 if (bpc->pc.frame_start_found <= 2+4+4) {
52 for (; i < buf_size; i++) {
53 state = (state << 8) | buf[i];
54 if (bpc->pc.frame_start_found == 0) {
55 if ((state >> 48) == (('B' << 8) | 'M')) {
56 bpc->fsize = av_bswap32(state >> 16);
57 if (bpc->fsize > 17)
58 bpc->pc.frame_start_found = 1;
59 }
60 } else if (bpc->pc.frame_start_found == 2+4+4) {
61 // unsigned hsize = av_bswap32(state>>32);
62 unsigned ihsize = av_bswap32(state);
63 if (ihsize < 12 || ihsize > 200) {
64 bpc->pc.frame_start_found = 0;
65 continue;
66 }
67 bpc->pc.frame_start_found++;
68 bpc->remaining_size = bpc->fsize + i - 17;
69
70 if (bpc->pc.index + i > 17) {
71 next = i - 17;
72 state = 0;
73 break;
74 } else {
75 bpc->pc.state64 = 0;
76 goto restart;
77 }
78 } else if (bpc->pc.frame_start_found)
79 bpc->pc.frame_start_found++;
80 }
81 bpc->pc.state64 = state;
82 } else {
83 if (bpc->remaining_size) {
84 i = FFMIN(bpc->remaining_size, buf_size);
85 bpc->remaining_size -= i;
86 if (bpc->remaining_size)
87 goto flush;
88
89 bpc->pc.frame_start_found = 0;
90 goto restart;
91 }
92 }
93
94 flush:
95 if (ff_combine_frame(&bpc->pc, next, &buf, &buf_size) < 0)
96 return buf_size;
97
98 if (next != END_NOT_FOUND && next < 0)
99 bpc->pc.frame_start_found = FFMAX(bpc->pc.frame_start_found - i - 1, 0);
100 else
101 bpc->pc.frame_start_found = 0;
102
103 *poutbuf = buf;
104 *poutbuf_size = buf_size;
105 return next;
106 }
107
108 AVCodecParser ff_bmp_parser = {
109 .codec_ids = { AV_CODEC_ID_BMP },
110 .priv_data_size = sizeof(BMPParseContext),
111 .parser_parse = bmp_parse,
112 .parser_close = ff_parse_close,
113 };
114