/* * 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;}