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
32typedef struct BMPParseContext {
33    ParseContext pc;
34    uint32_t fsize;
35    uint32_t remaining_size;
36} BMPParseContext;
37
38static 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
50restart:
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
94flush:
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
108const 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