1 /*
2 * DVD subtitle decoding
3 * Copyright (c) 2005 Fabrice Bellard
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 #include <string.h>
23
24 #include "libavutil/intreadwrite.h"
25 #include "libavutil/mem.h"
26 #include "avcodec.h"
27
28 /* parser definition */
29 typedef struct DVDSubParseContext {
30 uint8_t *packet;
31 int packet_len;
32 int packet_index;
33 } DVDSubParseContext;
34
dvdsub_parse(AVCodecParserContext * s,AVCodecContext * avctx,const uint8_t ** poutbuf,int * poutbuf_size,const uint8_t * buf,int buf_size)35 static int dvdsub_parse(AVCodecParserContext *s,
36 AVCodecContext *avctx,
37 const uint8_t **poutbuf, int *poutbuf_size,
38 const uint8_t *buf, int buf_size)
39 {
40 DVDSubParseContext *pc = s->priv_data;
41
42 *poutbuf = buf;
43 *poutbuf_size = buf_size;
44
45 if (pc->packet_index == 0) {
46 if (buf_size < 2 || AV_RB16(buf) && buf_size < 6) {
47 if (buf_size)
48 av_log(avctx, AV_LOG_DEBUG, "Parser input %d too small\n", buf_size);
49 return buf_size;
50 }
51 pc->packet_len = AV_RB16(buf);
52 if (pc->packet_len == 0) /* HD-DVD subpicture packet */
53 pc->packet_len = AV_RB32(buf+2);
54 av_freep(&pc->packet);
55 if ((unsigned)pc->packet_len > INT_MAX - AV_INPUT_BUFFER_PADDING_SIZE) {
56 av_log(avctx, AV_LOG_ERROR, "packet length %d is invalid\n", pc->packet_len);
57 return buf_size;
58 }
59 pc->packet = av_malloc(pc->packet_len + AV_INPUT_BUFFER_PADDING_SIZE);
60 }
61 if (pc->packet) {
62 if (pc->packet_index + buf_size <= pc->packet_len) {
63 memcpy(pc->packet + pc->packet_index, buf, buf_size);
64 pc->packet_index += buf_size;
65 if (pc->packet_index >= pc->packet_len) {
66 *poutbuf = pc->packet;
67 *poutbuf_size = pc->packet_len;
68 pc->packet_index = 0;
69 return buf_size;
70 }
71 } else {
72 /* erroneous size */
73 pc->packet_index = 0;
74 }
75 }
76 *poutbuf = NULL;
77 *poutbuf_size = 0;
78 return buf_size;
79 }
80
dvdsub_parse_close(AVCodecParserContext * s)81 static av_cold void dvdsub_parse_close(AVCodecParserContext *s)
82 {
83 DVDSubParseContext *pc = s->priv_data;
84 av_freep(&pc->packet);
85 }
86
87 AVCodecParser ff_dvdsub_parser = {
88 .codec_ids = { AV_CODEC_ID_DVD_SUBTITLE },
89 .priv_data_size = sizeof(DVDSubParseContext),
90 .parser_parse = dvdsub_parse,
91 .parser_close = dvdsub_parse_close,
92 };
93