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/*
* libmad - MPEG audio decoder library
* Copyright (C) 2000-2004 Underbit Technologies, Inc.
*
* 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: stream.c,v 1.12 2004/02/05 09:02:39 rob Exp $
*/
# ifdef HAVE_CONFIG_H
# include "config.h"
# endif
# include "global.h"
# include <stdlib.h>
# include "bit.h"
# include "stream.h"
/*
* NAME: stream->init()
* DESCRIPTION: initialize stream struct
*/
void mad_stream_init(struct mad_stream *stream)
{
stream->buffer = 0;
stream->bufend = 0;
stream->skiplen = 0;
stream->sync = 0;
stream->freerate = 0;
stream->this_frame = 0;
stream->next_frame = 0;
mad_bit_init(&stream->ptr, 0);
mad_bit_init(&stream->anc_ptr, 0);
stream->anc_bitlen = 0;
stream->main_data = 0;
stream->md_len = 0;
stream->options = 0;
stream->error = MAD_ERROR_NONE;
}
/*
* NAME: stream->finish()
* DESCRIPTION: deallocate any dynamic memory associated with stream
*/
void mad_stream_finish(struct mad_stream *stream)
{
if (stream->main_data) {
free(stream->main_data);
stream->main_data = 0;
}
mad_bit_finish(&stream->anc_ptr);
mad_bit_finish(&stream->ptr);
}
/*
* NAME: stream->buffer()
* DESCRIPTION: set stream buffer pointers
*/
void mad_stream_buffer(struct mad_stream *stream,
unsigned char const *buffer, unsigned long length)
{
stream->buffer = buffer;
stream->bufend = buffer + length;
stream->this_frame = buffer;
stream->next_frame = buffer;
stream->sync = 1;
mad_bit_init(&stream->ptr, buffer);
}
/*
* NAME: stream->skip()
* DESCRIPTION: arrange to skip bytes before the next frame
*/
void mad_stream_skip(struct mad_stream *stream, unsigned long length)
{
stream->skiplen += length;
}
/*
* NAME: stream->sync()
* DESCRIPTION: locate the next stream sync word
*/
int mad_stream_sync(struct mad_stream *stream)
{
register unsigned char const *ptr, *end;
ptr = mad_bit_nextbyte(&stream->ptr);
end = stream->bufend;
while (ptr < end - 1 &&
!(ptr[0] == 0xff && (ptr[1] & 0xe0) == 0xe0))
++ptr;
if (end - ptr < MAD_BUFFER_GUARD)
return -1;
mad_bit_init(&stream->ptr, ptr);
return 0;
}
/*
* NAME: stream->errorstr()
* DESCRIPTION: return a string description of the current error condition
*/
char const *mad_stream_errorstr(struct mad_stream const *stream)
{
switch (stream->error) {
case MAD_ERROR_NONE: return "no error";
case MAD_ERROR_BUFLEN: return "input buffer too small (or EOF)";
case MAD_ERROR_BUFPTR: return "invalid (null) buffer pointer";
case MAD_ERROR_NOMEM: return "not enough memory";
case MAD_ERROR_LOSTSYNC: return "lost synchronization";
case MAD_ERROR_BADLAYER: return "reserved header layer value";
case MAD_ERROR_BADBITRATE: return "forbidden bitrate value";
case MAD_ERROR_BADSAMPLERATE: return "reserved sample frequency value";
case MAD_ERROR_BADEMPHASIS: return "reserved emphasis value";
case MAD_ERROR_BADCRC: return "CRC check failed";
case MAD_ERROR_BADBITALLOC: return "forbidden bit allocation value";
case MAD_ERROR_BADSCALEFACTOR: return "bad scalefactor index";
case MAD_ERROR_BADMODE: return "bad bitrate/mode combination";
case MAD_ERROR_BADFRAMELEN: return "bad frame length";
case MAD_ERROR_BADBIGVALUES: return "bad big_values count";
case MAD_ERROR_BADBLOCKTYPE: return "reserved block_type";
case MAD_ERROR_BADSCFSI: return "bad scalefactor selection info";
case MAD_ERROR_BADDATAPTR: return "bad main_data_begin pointer";
case MAD_ERROR_BADPART3LEN: return "bad audio data length";
case MAD_ERROR_BADHUFFTABLE: return "bad Huffman table select";
case MAD_ERROR_BADHUFFDATA: return "Huffman data overrun";
case MAD_ERROR_BADSTEREO: return "incompatible block_type for JS";
}
return 0;
}
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