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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: stream.c,v 1.3 2001-11-06 17:01:28 simons Exp $

 */

# ifdef HAVE_CONFIG_H

#  include "config.h"

# endif

# include "global.h"

# include "bit.h"

# include "stream.h"

/*

 * NAME:        stream->init()

 * DESCRIPTION: initialize stream struct

 */

inline 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      = 0;

}

/*

 * NAME:        stream->finish()

 * DESCRIPTION: deallocate any dynamic memory associated with stream

 */

inline void mad_stream_finish(struct mad_stream *stream)

{

  mad_bit_finish(&stream->anc_ptr);

  mad_bit_finish(&stream->ptr);

}

/*

 * NAME:        stream->buffer()

 * DESCRIPTION: set stream buffer pointers

 */

inline 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

 */

static 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;

}