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# stream.h

    00001 /*
    00002  * libmad - MPEG audio decoder library
    00003  * Copyright (C) 2000-2003 Underbit Technologies, Inc.
    00004  *
    00005  * This program is free software; you can redistribute it and/or modify
    00006  * it under the terms of the GNU General Public License as published by
    00007  * the Free Software Foundation; either version 2 of the License, or
    00008  * (at your option) any later version.
    00009  *
    00010  * This program is distributed in the hope that it will be useful,
    00011  * but WITHOUT ANY WARRANTY; without even the implied warranty of
    00012  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    00013  * GNU General Public License for more details.
    00014  *
    00015  * You should have received a copy of the GNU General Public License
    00016  * along with this program; if not, write to the Free Software
    00017  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
    00018  *
    00019  * $Id: stream.h,v 1.1 2003/08/31 19:00:15 gabest Exp $
    00020  */
    00021
    00022 # ifndef LIBMAD_STREAM_H
    00023 # define LIBMAD_STREAM_H
    00024
    00025 # include "bit.h"
    00026
    00027 # define MAD_BUFFER_GUARD       8
    00028 # define MAD_BUFFER_MDLEN       (511 + 2048 + MAD_BUFFER_GUARD)
    00029
    00030 enum mad_error {
    00031   MAD_ERROR_NONE           = 0x0000,    /* no error */
    00032
    00033   MAD_ERROR_BUFLEN         = 0x0001,    /* input buffer too small (or EOF) */
    00034   MAD_ERROR_BUFPTR         = 0x0002,    /* invalid (null) buffer pointer */
    00035
    00036   MAD_ERROR_NOMEM          = 0x0031,    /* not enough memory */
    00037
    00038   MAD_ERROR_LOSTSYNC       = 0x0101,    /* lost synchronization */
    00039   MAD_ERROR_BADLAYER       = 0x0102,    /* reserved header layer value */
    00040   MAD_ERROR_BADBITRATE     = 0x0103,    /* forbidden bitrate value */
    00041   MAD_ERROR_BADSAMPLERATE  = 0x0104,    /* reserved sample frequency value */
    00042   MAD_ERROR_BADEMPHASIS    = 0x0105,    /* reserved emphasis value */
    00043
    00044   MAD_ERROR_BADCRC         = 0x0201,    /* CRC check failed */
    00045   MAD_ERROR_BADBITALLOC    = 0x0211,    /* forbidden bit allocation value */
    00046   MAD_ERROR_BADSCALEFACTOR = 0x0221,    /* bad scalefactor index */
    00047   MAD_ERROR_BADFRAMELEN    = 0x0231,    /* bad frame length */
    00048   MAD_ERROR_BADBIGVALUES   = 0x0232,    /* bad big_values count */
    00049   MAD_ERROR_BADBLOCKTYPE   = 0x0233,    /* reserved block_type */
    00050   MAD_ERROR_BADSCFSI       = 0x0234,    /* bad scalefactor selection info */
    00051   MAD_ERROR_BADDATAPTR     = 0x0235,    /* bad main_data_begin pointer */
    00052   MAD_ERROR_BADPART3LEN    = 0x0236,    /* bad audio data length */
    00053   MAD_ERROR_BADHUFFTABLE   = 0x0237,    /* bad Huffman table select */
    00054   MAD_ERROR_BADHUFFDATA    = 0x0238,    /* Huffman data overrun */
    00055   MAD_ERROR_BADSTEREO      = 0x0239     /* incompatible block_type for JS */
    00056 };
    00057
    00058 # define MAD_RECOVERABLE(error) ((error) & 0xff00)
    00059
    00060 struct mad_stream {
    00061   unsigned char const *buffer;          /* input bitstream buffer */
    00062   unsigned char const *bufend;          /* end of buffer */
    00063   unsigned long skiplen;                /* bytes to skip before next frame */
    00064
    00065   int sync;                             /* stream sync found */
    00066   unsigned long freerate;               /* free bitrate (fixed) */
    00067
    00068   unsigned char const *this_frame;      /* start of current frame */
    00069   unsigned char const *next_frame;      /* start of next frame */
    00070   struct mad_bitptr ptr;                /* current processing bit pointer */
    00071
    00072   struct mad_bitptr anc_ptr;            /* ancillary bits pointer */
    00073   unsigned int anc_bitlen;              /* number of ancillary bits */
    00074
    00075   unsigned char (*main_data)[MAD_BUFFER_MDLEN];
    00076                                         /* Layer III main_data() */
    00077   unsigned int md_len;                  /* bytes in main_data */
    00078
    00079   int options;                          /* decoding options (see below) */
    00080   enum mad_error error;                 /* error code (see above) */
    00081 };
    00082
    00083 enum {
    00084   MAD_OPTION_IGNORECRC      = 0x0001,   /* ignore CRC errors */
    00085   MAD_OPTION_HALFSAMPLERATE = 0x0002    /* generate PCM at 1/2 sample rate */
    00086 # if 0  /* not yet implemented */
    00087   MAD_OPTION_LEFTCHANNEL    = 0x0010,   /* decode left channel only */
    00088   MAD_OPTION_RIGHTCHANNEL   = 0x0020,   /* decode right channel only */
    00089   MAD_OPTION_SINGLECHANNEL  = 0x0030    /* combine channels */
    00090 # endif
    00091 };
    00092
    00093 void mad_stream_init(struct mad_stream *);
    00094 void mad_stream_finish(struct mad_stream *);
    00095
    00096 # define mad_stream_options(stream, opts)  \
    00097     ((void) ((stream)->options = (opts)))
    00098
    00099 void mad_stream_buffer(struct mad_stream *,
    00100                        unsigned char const *, unsigned long);
    00101 void mad_stream_skip(struct mad_stream *, unsigned long);
    00102
    00103 int mad_stream_sync(struct mad_stream *);
    00104
    00105 char const *mad_stream_errorstr(struct mad_stream const *);
    00106
    00107 # endif