1/*
2 * Metadata demuxer
3 * Copyright (c) 2010 Anton Khirnov
4 *
5 * This file is part of Libav.
6 *
7 * Libav 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 * Libav 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 Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22#include "libavutil/mathematics.h"
23#include "avformat.h"
24#include "ffmeta.h"
25#include "internal.h"
26#include "libavutil/dict.h"
27
28static int probe(AVProbeData *p)
29{
30    if(!memcmp(p->buf, ID_STRING, strlen(ID_STRING)))
31        return AVPROBE_SCORE_MAX;
32    return 0;
33}
34
35static void get_line(AVIOContext *s, uint8_t *buf, int size)
36{
37    do {
38        uint8_t c;
39        int i = 0;
40
41        while ((c = avio_r8(s))) {
42            if (c == '\\') {
43                if (i < size - 1)
44                    buf[i++] = c;
45                c = avio_r8(s);
46            } else if (c == '\n')
47                break;
48
49            if (i < size - 1)
50                buf[i++] = c;
51        }
52        buf[i] = 0;
53    } while (!s->eof_reached && (buf[0] == ';' || buf[0] == '#' || buf[0] == 0));
54}
55
56static AVChapter *read_chapter(AVFormatContext *s)
57{
58    uint8_t line[256];
59    int64_t start, end;
60    AVRational tb = {1, 1e9};
61
62    get_line(s->pb, line, sizeof(line));
63
64    if (sscanf(line, "TIMEBASE=%d/%d", &tb.num, &tb.den))
65        get_line(s->pb, line, sizeof(line));
66    if (!sscanf(line, "START=%"SCNd64, &start)) {
67        av_log(s, AV_LOG_ERROR, "Expected chapter start timestamp, found %s.\n", line);
68        start = (s->nb_chapters && s->chapters[s->nb_chapters - 1]->end != AV_NOPTS_VALUE) ?
69                 s->chapters[s->nb_chapters - 1]->end : 0;
70    } else
71        get_line(s->pb, line, sizeof(line));
72
73    if (!sscanf(line, "END=%"SCNd64, &end)) {
74        av_log(s, AV_LOG_ERROR, "Expected chapter end timestamp, found %s.\n", line);
75        end = AV_NOPTS_VALUE;
76    }
77
78    return avpriv_new_chapter(s, s->nb_chapters, tb, start, end, NULL);
79}
80
81static uint8_t *unescape(uint8_t *buf, int size)
82{
83    uint8_t *ret = av_malloc(size + 1);
84    uint8_t *p1  = ret, *p2 = buf;
85
86    if (!ret)
87        return NULL;
88
89    while (p2 < buf + size) {
90        if (*p2 == '\\')
91            p2++;
92        *p1++ = *p2++;
93    }
94    *p1 = 0;
95    return ret;
96}
97
98static int read_tag(uint8_t *line, AVDictionary **m)
99{
100    uint8_t *key, *value, *p = line;
101
102    /* find first not escaped '=' */
103    while (1) {
104        if (*p == '=')
105            break;
106        else if (*p == '\\')
107            p++;
108
109        if (*p++)
110            continue;
111
112        return 0;
113    }
114
115    if (!(key = unescape(line, p - line)))
116        return AVERROR(ENOMEM);
117    if (!(value = unescape(p + 1, strlen(p + 1)))) {
118        av_free(key);
119        return AVERROR(ENOMEM);
120    }
121
122    av_dict_set(m, key, value, AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
123    return 0;
124}
125
126static int read_header(AVFormatContext *s, AVFormatParameters *ap)
127{
128    AVDictionary **m = &s->metadata;
129    uint8_t line[1024];
130
131    while(!s->pb->eof_reached) {
132        get_line(s->pb, line, sizeof(line));
133
134        if (!memcmp(line, ID_STREAM, strlen(ID_STREAM))) {
135            AVStream *st = avformat_new_stream(s, NULL);
136
137            if (!st)
138                return -1;
139
140            st->codec->codec_type = AVMEDIA_TYPE_DATA;
141            st->codec->codec_id   = CODEC_ID_FFMETADATA;
142
143            m = &st->metadata;
144        } else if (!memcmp(line, ID_CHAPTER, strlen(ID_CHAPTER))) {
145            AVChapter *ch = read_chapter(s);
146
147            if (!ch)
148                return -1;
149
150            m = &ch->metadata;
151        } else
152            read_tag(line, m);
153    }
154
155    s->start_time = 0;
156    if (s->nb_chapters)
157        s->duration = av_rescale_q(s->chapters[s->nb_chapters - 1]->end,
158                                   s->chapters[s->nb_chapters - 1]->time_base,
159                                   AV_TIME_BASE_Q);
160
161    return 0;
162}
163
164static int read_packet(AVFormatContext *s, AVPacket *pkt)
165{
166    return AVERROR_EOF;
167}
168
169AVInputFormat ff_ffmetadata_demuxer = {
170    .name        = "ffmetadata",
171    .long_name   = NULL_IF_CONFIG_SMALL("FFmpeg metadata in text format"),
172    .read_probe  = probe,
173    .read_header = read_header,
174    .read_packet = read_packet,
175};
176