stream.h

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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.h,v 1.20 2004/02/05 09:02:39 rob Exp $
 */

# ifndef LIBMAD_STREAM_H
# define LIBMAD_STREAM_H
 
# include "bit.h"
 
# define MAD_BUFFER_GUARD   8
# define MAD_BUFFER_MDLEN   (511 + 2048 + MAD_BUFFER_GUARD)
 
enum mad_error {
  MAD_ERROR_NONE       = 0x0000,    /* no error */
 
  MAD_ERROR_BUFLEN     = 0x0001,    /* input buffer too small (or EOF) */
  MAD_ERROR_BUFPTR     = 0x0002,    /* invalid (null) buffer pointer */
 
  MAD_ERROR_NOMEM      = 0x0031,    /* not enough memory */
 
  MAD_ERROR_LOSTSYNC       = 0x0101,    /* lost synchronization */
  MAD_ERROR_BADLAYER       = 0x0102,    /* reserved header layer value */
  MAD_ERROR_BADBITRATE     = 0x0103,    /* forbidden bitrate value */
  MAD_ERROR_BADSAMPLERATE  = 0x0104,    /* reserved sample frequency value */
  MAD_ERROR_BADEMPHASIS    = 0x0105,    /* reserved emphasis value */
 
  MAD_ERROR_BADCRC     = 0x0201,    /* CRC check failed */
  MAD_ERROR_BADBITALLOC    = 0x0211,    /* forbidden bit allocation value */
  MAD_ERROR_BADSCALEFACTOR = 0x0221,    /* bad scalefactor index */
  MAD_ERROR_BADMODE        = 0x0222,    /* bad bitrate/mode combination */
  MAD_ERROR_BADFRAMELEN    = 0x0231,    /* bad frame length */
  MAD_ERROR_BADBIGVALUES   = 0x0232,    /* bad big_values count */
  MAD_ERROR_BADBLOCKTYPE   = 0x0233,    /* reserved block_type */
  MAD_ERROR_BADSCFSI       = 0x0234,    /* bad scalefactor selection info */
  MAD_ERROR_BADDATAPTR     = 0x0235,    /* bad main_data_begin pointer */
  MAD_ERROR_BADPART3LEN    = 0x0236,    /* bad audio data length */
  MAD_ERROR_BADHUFFTABLE   = 0x0237,    /* bad Huffman table select */
  MAD_ERROR_BADHUFFDATA    = 0x0238,    /* Huffman data overrun */
  MAD_ERROR_BADSTEREO      = 0x0239 /* incompatible block_type for JS */
};
 
# define MAD_RECOVERABLE(error) ((error) & 0xff00)
 
struct mad_stream {
  unsigned char const *buffer;      /* input bitstream buffer */
  unsigned char const *bufend;      /* end of buffer */
  unsigned long skiplen;        /* bytes to skip before next frame */
 
  int sync;             /* stream sync found */
  unsigned long freerate;       /* free bitrate (fixed) */
 
  unsigned char const *this_frame;  /* start of current frame */
  unsigned char const *next_frame;  /* start of next frame */
  struct mad_bitptr ptr;        /* current processing bit pointer */
 
  struct mad_bitptr anc_ptr;        /* ancillary bits pointer */
  unsigned int anc_bitlen;      /* number of ancillary bits */
 
  unsigned char (*main_data)[MAD_BUFFER_MDLEN];
                    /* Layer III main_data() */
  unsigned int md_len;          /* bytes in main_data */
 
  int options;              /* decoding options (see below) */
  enum mad_error error;         /* error code (see above) */
};
 
enum {
  MAD_OPTION_IGNORECRC      = 0x0001,   /* ignore CRC errors */
  MAD_OPTION_HALFSAMPLERATE = 0x0002    /* generate PCM at 1/2 sample rate */
# if 0  /* not yet implemented */
  MAD_OPTION_LEFTCHANNEL    = 0x0010,   /* decode left channel only */
  MAD_OPTION_RIGHTCHANNEL   = 0x0020,   /* decode right channel only */
  MAD_OPTION_SINGLECHANNEL  = 0x0030    /* combine channels */
# endif
};
 
void mad_stream_init(struct mad_stream *);
void mad_stream_finish(struct mad_stream *);
 
# define mad_stream_options(stream, opts)  \
    ((void) ((stream)->options = (opts)))
 
void mad_stream_buffer(struct mad_stream *,
               unsigned char const *, unsigned long);
void mad_stream_skip(struct mad_stream *, unsigned long);
 
int mad_stream_sync(struct mad_stream *);
 
char const *mad_stream_errorstr(struct mad_stream const *);
 
# endif