audiolib/audio/deps/mp3/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 $
 */

#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) {
    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);

    stream->main_data = malloc(MAD_BUFFER_MDLEN);
    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) {
    if (stream->main_data) {
        free(stream->main_data);
        stream->main_data = 0;
    }

    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)
{
    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) {
    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;
}

/*
 * NAME:	stream->errorstr()
 * DESCRIPTION:	return a string description of the current error condition
 */
char const *mad_stream_errorstr(struct mad_stream const *stream) {
    switch (stream->error) {
        case MAD_ERROR_NONE:
            return "no error";

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

        case MAD_ERROR_NOMEM:
            return "not enough memory";

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

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

    return 0;
}