1/*
2 * Copyright (c) 2012 Cl��ment B��sch
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21/**
22 * @file
23 * SAMI subtitle demuxer
24 * @see http://msdn.microsoft.com/en-us/library/ms971327.aspx
25 */
26
27#include "avformat.h"
28#include "internal.h"
29#include "subtitles.h"
30#include "libavcodec/internal.h"
31#include "libavutil/avstring.h"
32#include "libavutil/bprint.h"
33#include "libavutil/intreadwrite.h"
34
35typedef struct {
36    FFDemuxSubtitlesQueue q;
37} SAMIContext;
38
39static int sami_probe(AVProbeData *p)
40{
41    const unsigned char *ptr = p->buf;
42
43    if (AV_RB24(ptr) == 0xEFBBBF)
44        ptr += 3;  /* skip UTF-8 BOM */
45    return !strncmp(ptr, "<SAMI>", 6) ? AVPROBE_SCORE_MAX : 0;
46}
47
48static int sami_read_header(AVFormatContext *s)
49{
50    SAMIContext *sami = s->priv_data;
51    AVStream *st = avformat_new_stream(s, NULL);
52    AVBPrint buf, hdr_buf;
53    char c = 0;
54    int res = 0, got_first_sync_point = 0;
55
56    if (!st)
57        return AVERROR(ENOMEM);
58    avpriv_set_pts_info(st, 64, 1, 1000);
59    st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
60    st->codec->codec_id   = AV_CODEC_ID_SAMI;
61
62    av_bprint_init(&buf,     0, AV_BPRINT_SIZE_UNLIMITED);
63    av_bprint_init(&hdr_buf, 0, AV_BPRINT_SIZE_UNLIMITED);
64
65    while (!url_feof(s->pb)) {
66        AVPacket *sub;
67        const int64_t pos = avio_tell(s->pb) - (c != 0);
68        int is_sync, n = ff_smil_extract_next_chunk(s->pb, &buf, &c);
69
70        if (n == 0)
71            break;
72
73        is_sync = !av_strncasecmp(buf.str, "<SYNC", 5);
74        if (is_sync)
75            got_first_sync_point = 1;
76
77        if (!got_first_sync_point) {
78            av_bprintf(&hdr_buf, "%s", buf.str);
79        } else {
80            sub = ff_subtitles_queue_insert(&sami->q, buf.str, buf.len, !is_sync);
81            if (!sub) {
82                res = AVERROR(ENOMEM);
83                goto end;
84            }
85            if (is_sync) {
86                const char *p = ff_smil_get_attr_ptr(buf.str, "Start");
87                sub->pos      = pos;
88                sub->pts      = p ? strtol(p, NULL, 10) : 0;
89                sub->duration = -1;
90            }
91        }
92        av_bprint_clear(&buf);
93    }
94
95    res = avpriv_bprint_to_extradata(st->codec, &hdr_buf);
96    if (res < 0)
97        goto end;
98
99    ff_subtitles_queue_finalize(&sami->q);
100
101end:
102    av_bprint_finalize(&buf, NULL);
103    return res;
104}
105
106static int sami_read_packet(AVFormatContext *s, AVPacket *pkt)
107{
108    SAMIContext *sami = s->priv_data;
109    return ff_subtitles_queue_read_packet(&sami->q, pkt);
110}
111
112static int sami_read_seek(AVFormatContext *s, int stream_index,
113                          int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
114{
115    SAMIContext *sami = s->priv_data;
116    return ff_subtitles_queue_seek(&sami->q, s, stream_index,
117                                   min_ts, ts, max_ts, flags);
118}
119
120static int sami_read_close(AVFormatContext *s)
121{
122    SAMIContext *sami = s->priv_data;
123    ff_subtitles_queue_clean(&sami->q);
124    return 0;
125}
126
127AVInputFormat ff_sami_demuxer = {
128    .name           = "sami",
129    .long_name      = NULL_IF_CONFIG_SMALL("SAMI subtitle format"),
130    .priv_data_size = sizeof(SAMIContext),
131    .read_probe     = sami_probe,
132    .read_header    = sami_read_header,
133    .read_packet    = sami_read_packet,
134    .read_seek2     = sami_read_seek,
135    .read_close     = sami_read_close,
136    .extensions     = "smi,sami",
137};
138