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  1. /*
  2.  * Metadata demuxer
  3.  * Copyright (c) 2010 Anton Khirnov
  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 "libavutil/mathematics.h"
  23. #include "avformat.h"
  24. #include "ffmeta.h"
  25. #include "internal.h"
  26. #include "libavutil/dict.h"
  27.  
  28. static 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.  
  35. static 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 (!url_feof(s) && (buf[0] == ';' || buf[0] == '#' || buf[0] == 0));
  54. }
  55.  
  56. static 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.  
  81. static 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.  
  98. static 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.  
  126. static int read_header(AVFormatContext *s)
  127. {
  128.     AVDictionary **m = &s->metadata;
  129.     uint8_t line[1024];
  130.  
  131.     while(!url_feof(s->pb)) {
  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 AVERROR(ENOMEM);
  139.  
  140.             st->codec->codec_type = AVMEDIA_TYPE_DATA;
  141.             st->codec->codec_id   = AV_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 AVERROR(ENOMEM);
  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.  
  164. static int read_packet(AVFormatContext *s, AVPacket *pkt)
  165. {
  166.     return AVERROR_EOF;
  167. }
  168.  
  169. AVInputFormat ff_ffmetadata_demuxer = {
  170.     .name        = "ffmetadata",
  171.     .long_name   = NULL_IF_CONFIG_SMALL("FFmpeg metadata in text"),
  172.     .read_probe  = probe,
  173.     .read_header = read_header,
  174.     .read_packet = read_packet,
  175. };
  176.