FFmpeg: libavformat/id3v2.c Source File

00001 /*
00002  * ID3v2 header parser
00003  * Copyright (c) 2003 Fabrice Bellard
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 #include "id3v2.h"
00023 
00024 int ff_id3v2_match(const uint8_t *buf)
00025 {
00026     return  buf[0] == 'I' &&
00027             buf[1] == 'D' &&
00028             buf[2] == '3' &&
00029             buf[3] != 0xff &&
00030             buf[4] != 0xff &&
00031             (buf[6] & 0x80) == 0 &&
00032             (buf[7] & 0x80) == 0 &&
00033             (buf[8] & 0x80) == 0 &&
00034             (buf[9] & 0x80) == 0;
00035 }
00036 
00037 int ff_id3v2_tag_len(const uint8_t * buf)
00038 {
00039     int len = ((buf[6] & 0x7f) << 21) +
00040         ((buf[7] & 0x7f) << 14) +
00041         ((buf[8] & 0x7f) << 7) +
00042         (buf[9] & 0x7f) +
00043         ID3v2_HEADER_SIZE;
00044     if (buf[5] & 0x10)
00045         len += ID3v2_HEADER_SIZE;
00046     return len;
00047 }