ref: 27d3b4682ffd297e72120577a66c424ca0644cc5
dir: /sys/src/cmd/audio/mp3dec/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 $ */ # ifdef HAVE_CONFIG_H # include "config.h" # endif # include "global.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); mad_bit_init(&stream->anc_ptr, 0); stream->anc_bitlen = 0; stream->main_data = 0; 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->anc_ptr); 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; }