Chris@0: /*
Chris@0:  * libmad - MPEG audio decoder library
Chris@0:  * Copyright (C) 2000-2004 Underbit Technologies, Inc.
Chris@0:  *
Chris@0:  * This program is free software; you can redistribute it and/or modify
Chris@0:  * it under the terms of the GNU General Public License as published by
Chris@0:  * the Free Software Foundation; either version 2 of the License, or
Chris@0:  * (at your option) any later version.
Chris@0:  *
Chris@0:  * This program is distributed in the hope that it will be useful,
Chris@0:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
Chris@0:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
Chris@0:  * GNU General Public License for more details.
Chris@0:  *
Chris@0:  * You should have received a copy of the GNU General Public License
Chris@0:  * along with this program; if not, write to the Free Software
Chris@0:  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
Chris@0:  *
Chris@0:  * $Id: stream.c,v 1.12 2004/02/05 09:02:39 rob Exp $
Chris@0:  */
Chris@0: 
Chris@0: # ifdef HAVE_CONFIG_H
Chris@0: #  include "config.h"
Chris@0: # endif
Chris@0: 
Chris@0: # include "global.h"
Chris@0: 
Chris@0: # include <stdlib.h>
Chris@0: 
Chris@0: # include "bit.h"
Chris@0: # include "stream.h"
Chris@0: 
Chris@0: /*
Chris@0:  * NAME:	stream->init()
Chris@0:  * DESCRIPTION:	initialize stream struct
Chris@0:  */
Chris@0: void mad_stream_init(struct mad_stream *stream)
Chris@0: {
Chris@0:   stream->buffer     = 0;
Chris@0:   stream->bufend     = 0;
Chris@0:   stream->skiplen    = 0;
Chris@0: 
Chris@0:   stream->sync       = 0;
Chris@0:   stream->freerate   = 0;
Chris@0: 
Chris@0:   stream->this_frame = 0;
Chris@0:   stream->next_frame = 0;
Chris@0:   mad_bit_init(&stream->ptr, 0);
Chris@0: 
Chris@0:   mad_bit_init(&stream->anc_ptr, 0);
Chris@0:   stream->anc_bitlen = 0;
Chris@0: 
Chris@0:   stream->main_data  = 0;
Chris@0:   stream->md_len     = 0;
Chris@0: 
Chris@0:   stream->options    = 0;
Chris@0:   stream->error      = MAD_ERROR_NONE;
Chris@0: }
Chris@0: 
Chris@0: /*
Chris@0:  * NAME:	stream->finish()
Chris@0:  * DESCRIPTION:	deallocate any dynamic memory associated with stream
Chris@0:  */
Chris@0: void mad_stream_finish(struct mad_stream *stream)
Chris@0: {
Chris@0:   if (stream->main_data) {
Chris@0:     free(stream->main_data);
Chris@0:     stream->main_data = 0;
Chris@0:   }
Chris@0: 
Chris@0:   mad_bit_finish(&stream->anc_ptr);
Chris@0:   mad_bit_finish(&stream->ptr);
Chris@0: }
Chris@0: 
Chris@0: /*
Chris@0:  * NAME:	stream->buffer()
Chris@0:  * DESCRIPTION:	set stream buffer pointers
Chris@0:  */
Chris@0: void mad_stream_buffer(struct mad_stream *stream,
Chris@0: 		       unsigned char const *buffer, unsigned long length)
Chris@0: {
Chris@0:   stream->buffer = buffer;
Chris@0:   stream->bufend = buffer + length;
Chris@0: 
Chris@0:   stream->this_frame = buffer;
Chris@0:   stream->next_frame = buffer;
Chris@0: 
Chris@0:   stream->sync = 1;
Chris@0: 
Chris@0:   mad_bit_init(&stream->ptr, buffer);
Chris@0: }
Chris@0: 
Chris@0: /*
Chris@0:  * NAME:	stream->skip()
Chris@0:  * DESCRIPTION:	arrange to skip bytes before the next frame
Chris@0:  */
Chris@0: void mad_stream_skip(struct mad_stream *stream, unsigned long length)
Chris@0: {
Chris@0:   stream->skiplen += length;
Chris@0: }
Chris@0: 
Chris@0: /*
Chris@0:  * NAME:	stream->sync()
Chris@0:  * DESCRIPTION:	locate the next stream sync word
Chris@0:  */
Chris@0: int mad_stream_sync(struct mad_stream *stream)
Chris@0: {
Chris@0:   register unsigned char const *ptr, *end;
Chris@0: 
Chris@0:   ptr = mad_bit_nextbyte(&stream->ptr);
Chris@0:   end = stream->bufend;
Chris@0: 
Chris@0:   while (ptr < end - 1 &&
Chris@0: 	 !(ptr[0] == 0xff && (ptr[1] & 0xe0) == 0xe0))
Chris@0:     ++ptr;
Chris@0: 
Chris@0:   if (end - ptr < MAD_BUFFER_GUARD)
Chris@0:     return -1;
Chris@0: 
Chris@0:   mad_bit_init(&stream->ptr, ptr);
Chris@0: 
Chris@0:   return 0;
Chris@0: }
Chris@0: 
Chris@0: /*
Chris@0:  * NAME:	stream->errorstr()
Chris@0:  * DESCRIPTION:	return a string description of the current error condition
Chris@0:  */
Chris@0: char const *mad_stream_errorstr(struct mad_stream const *stream)
Chris@0: {
Chris@0:   switch (stream->error) {
Chris@0:   case MAD_ERROR_NONE:		 return "no error";
Chris@0: 
Chris@0:   case MAD_ERROR_BUFLEN:	 return "input buffer too small (or EOF)";
Chris@0:   case MAD_ERROR_BUFPTR:	 return "invalid (null) buffer pointer";
Chris@0: 
Chris@0:   case MAD_ERROR_NOMEM:		 return "not enough memory";
Chris@0: 
Chris@0:   case MAD_ERROR_LOSTSYNC:	 return "lost synchronization";
Chris@0:   case MAD_ERROR_BADLAYER:	 return "reserved header layer value";
Chris@0:   case MAD_ERROR_BADBITRATE:	 return "forbidden bitrate value";
Chris@0:   case MAD_ERROR_BADSAMPLERATE:	 return "reserved sample frequency value";
Chris@0:   case MAD_ERROR_BADEMPHASIS:	 return "reserved emphasis value";
Chris@0: 
Chris@0:   case MAD_ERROR_BADCRC:	 return "CRC check failed";
Chris@0:   case MAD_ERROR_BADBITALLOC:	 return "forbidden bit allocation value";
Chris@0:   case MAD_ERROR_BADSCALEFACTOR: return "bad scalefactor index";
Chris@0:   case MAD_ERROR_BADMODE:	 return "bad bitrate/mode combination";
Chris@0:   case MAD_ERROR_BADFRAMELEN:	 return "bad frame length";
Chris@0:   case MAD_ERROR_BADBIGVALUES:	 return "bad big_values count";
Chris@0:   case MAD_ERROR_BADBLOCKTYPE:	 return "reserved block_type";
Chris@0:   case MAD_ERROR_BADSCFSI:	 return "bad scalefactor selection info";
Chris@0:   case MAD_ERROR_BADDATAPTR:	 return "bad main_data_begin pointer";
Chris@0:   case MAD_ERROR_BADPART3LEN:	 return "bad audio data length";
Chris@0:   case MAD_ERROR_BADHUFFTABLE:	 return "bad Huffman table select";
Chris@0:   case MAD_ERROR_BADHUFFDATA:	 return "Huffman data overrun";
Chris@0:   case MAD_ERROR_BADSTEREO:	 return "incompatible block_type for JS";
Chris@0:   }
Chris@0: 
Chris@0:   return 0;
Chris@0: }