160 lines
4.3 KiB
C
160 lines
4.3 KiB
C
/*
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* libmad - MPEG audio decoder library
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* Copyright (C) 2000-2004 Underbit Technologies, Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* $Id: stream.c,v 1.12 2004/02/05 09:02:39 rob Exp $
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*/
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# ifdef HAVE_CONFIG_H
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# include "config.h"
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# endif
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# include "global.h"
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# include "bit.h"
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# include "stream.h"
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/*
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* NAME: stream->init()
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* DESCRIPTION: initialize stream struct
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*/
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void mad_stream_init(struct mad_stream *stream)
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{
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stream->buffer = 0;
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stream->bufend = 0;
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stream->skiplen = 0;
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stream->sync = 0;
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stream->freerate = 0;
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stream->this_frame = 0;
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stream->next_frame = 0;
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mad_bit_init(&stream->ptr, 0);
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mad_bit_init(&stream->anc_ptr, 0);
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stream->anc_bitlen = 0;
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stream->main_data = 0;
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stream->md_len = 0;
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stream->options = 0;
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stream->error = MAD_ERROR_NONE;
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}
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/*
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* NAME: stream->finish()
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* DESCRIPTION: deallocate any dynamic memory associated with stream
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*/
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void mad_stream_finish(struct mad_stream *stream)
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{
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if (stream->main_data) {
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free(stream->main_data);
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stream->main_data = 0;
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}
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mad_bit_finish(&stream->anc_ptr);
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mad_bit_finish(&stream->ptr);
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}
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/*
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* NAME: stream->buffer()
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* DESCRIPTION: set stream buffer pointers
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*/
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void mad_stream_buffer(struct mad_stream *stream,
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unsigned char const *buffer, unsigned long length)
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{
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stream->buffer = buffer;
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stream->bufend = buffer + length;
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stream->this_frame = buffer;
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stream->next_frame = buffer;
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stream->sync = 1;
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mad_bit_init(&stream->ptr, buffer);
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}
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/*
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* NAME: stream->skip()
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* DESCRIPTION: arrange to skip bytes before the next frame
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*/
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void mad_stream_skip(struct mad_stream *stream, unsigned long length)
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{
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stream->skiplen += length;
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}
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/*
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* NAME: stream->sync()
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* DESCRIPTION: locate the next stream sync word
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*/
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int mad_stream_sync(struct mad_stream *stream)
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{
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register unsigned char const *ptr, *end;
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ptr = mad_bit_nextbyte(&stream->ptr);
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end = stream->bufend;
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while (ptr < end - 1 &&
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!(ptr[0] == 0xff && (ptr[1] & 0xe0) == 0xe0))
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++ptr;
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if (end - ptr < MAD_BUFFER_GUARD)
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return -1;
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mad_bit_init(&stream->ptr, ptr);
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return 0;
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}
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/*
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* NAME: stream->errorstr()
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* DESCRIPTION: return a string description of the current error condition
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*/
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char const *mad_stream_errorstr(struct mad_stream const *stream)
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{
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switch (stream->error) {
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case MAD_ERROR_NONE: return "no error";
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case MAD_ERROR_BUFLEN: return "input buffer too small (or EOF)";
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case MAD_ERROR_BUFPTR: return "invalid (null) buffer pointer";
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case MAD_ERROR_NOMEM: return "not enough memory";
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case MAD_ERROR_LOSTSYNC: return "lost synchronization";
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case MAD_ERROR_BADLAYER: return "reserved header layer value";
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case MAD_ERROR_BADBITRATE: return "forbidden bitrate value";
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case MAD_ERROR_BADSAMPLERATE: return "reserved sample frequency value";
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case MAD_ERROR_BADEMPHASIS: return "reserved emphasis value";
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case MAD_ERROR_BADCRC: return "CRC check failed";
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case MAD_ERROR_BADBITALLOC: return "forbidden bit allocation value";
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case MAD_ERROR_BADSCALEFACTOR: return "bad scalefactor index";
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case MAD_ERROR_BADMODE: return "bad bitrate/mode combination";
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case MAD_ERROR_BADFRAMELEN: return "bad frame length";
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case MAD_ERROR_BADBIGVALUES: return "bad big_values count";
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case MAD_ERROR_BADBLOCKTYPE: return "reserved block_type";
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case MAD_ERROR_BADSCFSI: return "bad scalefactor selection info";
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case MAD_ERROR_BADDATAPTR: return "bad main_data_begin pointer";
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case MAD_ERROR_BADPART3LEN: return "bad audio data length";
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case MAD_ERROR_BADHUFFTABLE: return "bad Huffman table select";
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case MAD_ERROR_BADHUFFDATA: return "Huffman data overrun";
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case MAD_ERROR_BADSTEREO: return "incompatible block_type for JS";
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}
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return 0;
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}
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