1/*
2 * SSA/ASS demuxer
3 * Copyright (c) 2008 Michael Niedermayer
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 "avformat.h"
23
24#define MAX_LINESIZE 2000
25
26typedef struct ASSContext{
27    uint8_t *event_buffer;
28    uint8_t **event;
29    unsigned int event_count;
30    unsigned int event_index;
31}ASSContext;
32
33static void get_line(ByteIOContext *s, char *buf, int maxlen)
34{
35    int i = 0;
36    char c;
37
38    do{
39        c = get_byte(s);
40        if (i < maxlen-1)
41            buf[i++] = c;
42    }while(c != '\n' && c);
43
44    buf[i] = 0;
45}
46
47static int probe(AVProbeData *p)
48{
49    const char *header= "[Script Info]";
50
51    if(   !memcmp(p->buf  , header, strlen(header))
52       || !memcmp(p->buf+3, header, strlen(header)))
53        return AVPROBE_SCORE_MAX;
54
55    return 0;
56}
57
58static int read_close(AVFormatContext *s)
59{
60    ASSContext *ass = s->priv_data;
61
62    av_freep(&ass->event_buffer);
63    av_freep(&ass->event);
64
65    return 0;
66}
67
68static int64_t get_pts(const uint8_t *p)
69{
70    int hour, min, sec, hsec;
71
72    if(sscanf(p, "%*[^,],%d:%d:%d%*c%d", &hour, &min, &sec, &hsec) != 4)
73        return AV_NOPTS_VALUE;
74
75//    av_log(NULL, AV_LOG_ERROR, "%d %d %d %d %d [%s]\n", i, hour, min, sec, hsec, p);
76
77    min+= 60*hour;
78    sec+= 60*min;
79
80    return sec*100+hsec;
81}
82
83static int event_cmp(uint8_t **a, uint8_t **b)
84{
85    return get_pts(*a) - get_pts(*b);
86}
87
88static int read_header(AVFormatContext *s, AVFormatParameters *ap)
89{
90    int i, header_remaining;
91    ASSContext *ass = s->priv_data;
92    ByteIOContext *pb = s->pb;
93    AVStream *st;
94    int allocated[2]={0};
95    uint8_t *p, **dst[2]={0};
96    int pos[2]={0};
97
98    st = av_new_stream(s, 0);
99    if (!st)
100        return -1;
101    av_set_pts_info(st, 64, 1, 100);
102    st->codec->codec_type = CODEC_TYPE_SUBTITLE;
103    st->codec->codec_id= CODEC_ID_SSA;
104
105    header_remaining= INT_MAX;
106    dst[0] = &st->codec->extradata;
107    dst[1] = &ass->event_buffer;
108    while(!url_feof(pb)){
109        uint8_t line[MAX_LINESIZE];
110
111        get_line(pb, line, sizeof(line));
112
113        if(!memcmp(line, "[Events]", 8))
114            header_remaining= 2;
115        else if(line[0]=='[')
116            header_remaining= INT_MAX;
117
118        i= header_remaining==0;
119
120        if(i && get_pts(line) == AV_NOPTS_VALUE)
121            continue;
122
123        p = av_fast_realloc(*(dst[i]), &allocated[i], pos[i]+MAX_LINESIZE);
124        if(!p)
125            goto fail;
126        *(dst[i])= p;
127        memcpy(p + pos[i], line, strlen(line)+1);
128        pos[i] += strlen(line);
129        if(i) ass->event_count++;
130        else  header_remaining--;
131    }
132    st->codec->extradata_size= pos[0];
133
134    if(ass->event_count >= UINT_MAX / sizeof(*ass->event))
135        goto fail;
136
137    ass->event= av_malloc(ass->event_count * sizeof(*ass->event));
138    p= ass->event_buffer;
139    for(i=0; i<ass->event_count; i++){
140        ass->event[i]= p;
141        while(*p && *p != '\n')
142            p++;
143        p++;
144    }
145
146    qsort(ass->event, ass->event_count, sizeof(*ass->event), (void*)event_cmp);
147
148    return 0;
149
150fail:
151    read_close(s);
152
153    return -1;
154}
155
156static int read_packet(AVFormatContext *s, AVPacket *pkt)
157{
158    ASSContext *ass = s->priv_data;
159    uint8_t *p, *end;
160
161    if(ass->event_index >= ass->event_count)
162        return AVERROR(EIO);
163
164    p= ass->event[ ass->event_index ];
165
166    end= strchr(p, '\n');
167    av_new_packet(pkt, end ? end-p+1 : strlen(p));
168    pkt->flags |= PKT_FLAG_KEY;
169    pkt->pos= p - ass->event_buffer + s->streams[0]->codec->extradata_size;
170    pkt->pts= pkt->dts= get_pts(p);
171    memcpy(pkt->data, p, pkt->size);
172
173    ass->event_index++;
174
175    return 0;
176}
177
178AVInputFormat ass_demuxer = {
179    "ass",
180    NULL_IF_CONFIG_SMALL("SSA/ASS format"),
181    sizeof(ASSContext),
182    probe,
183    read_header,
184    read_packet,
185    read_close,
186//    read_seek,
187};
188