stream.c

/*
 * 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 $
 */

#pragma GCC optimize ("O3")

#include <pgmspace.h>
#  include "config.h"

# 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)
{
stack(__FUNCTION__, __FILE__, __LINE__);
  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)
{
stack(__FUNCTION__, __FILE__, __LINE__);
  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)
{
stack(__FUNCTION__, __FILE__, __LINE__);
  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)
{
stack(__FUNCTION__, __FILE__, __LINE__);
  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;
stack(__FUNCTION__, __FILE__, __LINE__);

  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)
{
stack(__FUNCTION__, __FILE__, __LINE__);
  switch (stream->error) {
  case MAD_ERROR_NONE:		 return PSTR("no error");

  case MAD_ERROR_BUFLEN:	 return PSTR("input buffer too small (or EOF)");
  case MAD_ERROR_BUFPTR:	 return PSTR("invalid (null) buffer pointer");

  case MAD_ERROR_NOMEM:		 return PSTR("not enough memory");

  case MAD_ERROR_LOSTSYNC:	 return PSTR("lost synchronization");
  case MAD_ERROR_BADLAYER:	 return PSTR("reserved header layer value");
  case MAD_ERROR_BADBITRATE:	 return PSTR("forbidden bitrate value");
  case MAD_ERROR_BADSAMPLERATE:	 return PSTR("reserved sample frequency value");
  case MAD_ERROR_BADEMPHASIS:	 return PSTR("reserved emphasis value");

  case MAD_ERROR_BADCRC:	 return PSTR("CRC check failed");
  case MAD_ERROR_BADBITALLOC:	 return PSTR("forbidden bit allocation value");
  case MAD_ERROR_BADSCALEFACTOR: return PSTR("bad scalefactor index");
  case MAD_ERROR_BADMODE:	 return PSTR("bad bitrate/mode combination");
  case MAD_ERROR_BADFRAMELEN:	 return PSTR("bad frame length");
  case MAD_ERROR_BADBIGVALUES:	 return PSTR("bad big_values count");
  case MAD_ERROR_BADBLOCKTYPE:	 return PSTR("reserved block_type");
  case MAD_ERROR_BADSCFSI:	 return PSTR("bad scalefactor selection info");
  case MAD_ERROR_BADDATAPTR:	 return PSTR("bad main_data_begin pointer");
  case MAD_ERROR_BADPART3LEN:	 return PSTR("bad audio data length");
  case MAD_ERROR_BADHUFFTABLE:	 return PSTR("bad Huffman table select");
  case MAD_ERROR_BADHUFFDATA:	 return PSTR("Huffman data overrun");
  case MAD_ERROR_BADSTEREO:	 return PSTR("incompatible block_type for JS");
  }

  return 0;
}