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/*
* mad - MPEG audio decoder
* Copyright (C) 2000-2001 Robert Leslie
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* $Id: xing.c,v 1.5 2002/11/18 16:32:21 daper Exp $
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <mad.h>
#include "xing.h"
#define XING_MAGIC (('X' << 24) | ('i' << 16) | ('n' << 8) | 'g')
/*
* NAME: xing->init()
* DESCRIPTION: initialize Xing structure
*/
void xing_init(struct xing *xing)
{
xing->flags = 0;
}
/*
* NAME: xing->parse()
* DESCRIPTION: parse a Xing VBR header
*/
int xing_parse(struct xing *xing, struct mad_bitptr ptr, unsigned int bitlen)
{
if (bitlen < 64 || mad_bit_read(&ptr, 32) != XING_MAGIC)
goto fail;
xing->flags = mad_bit_read(&ptr, 32);
bitlen -= 64;
if (xing->flags & XING_FRAMES) {
if (bitlen < 32)
goto fail;
xing->frames = mad_bit_read(&ptr, 32);
bitlen -= 32;
}
if (xing->flags & XING_BYTES) {
if (bitlen < 32)
goto fail;
xing->bytes = mad_bit_read(&ptr, 32);
bitlen -= 32;
}
if (xing->flags & XING_TOC) {
int i;
if (bitlen < 800)
goto fail;
for (i = 0; i < 100; ++i)
xing->toc[i] = mad_bit_read(&ptr, 8);
bitlen -= 800;
}
if (xing->flags & XING_SCALE) {
if (bitlen < 32)
goto fail;
xing->scale = mad_bit_read(&ptr, 32);
bitlen -= 32;
}
return 0;
fail:
xing->flags = 0;
return -1;
}
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