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 */
29typedef struct DVDSubParseContext {
30    uint8_t *packet;
31    int packet_len;
32    int packet_index;
33} DVDSubParseContext;
34
35static 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
81static av_cold void dvdsub_parse_close(AVCodecParserContext *s)
82{
83    DVDSubParseContext *pc = s->priv_data;
84    av_freep(&pc->packet);
85}
86
87const 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