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meta: add ID3 parsing helper

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This commit is contained in:
Francois Cartegnie 2016-09-05 14:36:08 +02:00
parent 1997f57dbe
commit 739b3ef2fb
1 changed files with 80 additions and 0 deletions
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modules/meta_engine/ID3Tag.h Normal file
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/*****************************************************************************
* ID3Tag.h : ID3v2 Parsing Helper
*****************************************************************************
* Copyright (C) 2016 VLC authors and VideoLAN
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
*****************************************************************************/
#ifndef ID3TAG_H
#define ID3TAG_H
static uint32_t ID3TAG_ReadSize( const uint8_t *p_buffer, bool b_syncsafe )
{
if( !b_syncsafe )
return GetDWBE( p_buffer );
return ( (uint32_t)p_buffer[3] & 0x7F ) |
(( (uint32_t)p_buffer[2] & 0x7F ) << 7) |
(( (uint32_t)p_buffer[1] & 0x7F ) << 14) |
(( (uint32_t)p_buffer[0] & 0x7F ) << 21);
}
static bool ID3TAG_IsTag( const uint8_t *p_buffer, bool b_footer )
{
return( memcmp(p_buffer, (b_footer) ? "3DI" : "ID3", 3) == 0 &&
p_buffer[3] < 0xFF &&
p_buffer[4] < 0xFF &&
((GetDWBE(&p_buffer[6]) & 0x80808080) == 0) );
}
static size_t ID3TAG_Parse( const uint8_t *p_peek, size_t i_peek,
int (*pf_callback)(uint32_t, const uint8_t *, size_t, void *), void *p_priv )
{
size_t i_total_size = 0;
uint32_t i_ID3size = 0;
if( i_peek > 10 && ID3TAG_IsTag( p_peek, false ) )
{
const bool b_syncsafe = p_peek[5] & 0x80;
i_ID3size = ID3TAG_ReadSize( &p_peek[6], true );
if( i_ID3size > i_peek - 10 )
return 0;
i_total_size = i_ID3size + 10;
const uint8_t *p_frame = &p_peek[10];
while( i_ID3size > 10 )
{
uint32_t i_tagname = VLC_FOURCC( p_frame[0], p_frame[1], p_frame[2], p_frame[3] );
uint32_t i_framesize = ID3TAG_ReadSize( &p_frame[4], b_syncsafe ) + 10;
if( i_framesize > i_ID3size )
return 0;
if( i_framesize > 10 &&
pf_callback( i_tagname, &p_frame[10], i_framesize - 10, p_priv ) != VLC_SUCCESS )
break;
p_frame += i_framesize;
i_ID3size -= i_framesize;
}
}
/* Count footer if any */
if( i_total_size && i_peek - i_total_size >= 10 &&
ID3TAG_IsTag( &p_peek[i_total_size], true ) )
{
i_total_size += 10;
}
return i_total_size;
}
#endif // ID3TAG_H