cannam@85: /* cannam@85: * libmad - MPEG audio decoder library cannam@85: * Copyright (C) 2000-2004 Underbit Technologies, Inc. cannam@85: * cannam@85: * This program is free software; you can redistribute it and/or modify cannam@85: * it under the terms of the GNU General Public License as published by cannam@85: * the Free Software Foundation; either version 2 of the License, or cannam@85: * (at your option) any later version. cannam@85: * cannam@85: * This program is distributed in the hope that it will be useful, cannam@85: * but WITHOUT ANY WARRANTY; without even the implied warranty of cannam@85: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the cannam@85: * GNU General Public License for more details. cannam@85: * cannam@85: * You should have received a copy of the GNU General Public License cannam@85: * along with this program; if not, write to the Free Software cannam@85: * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA cannam@85: * cannam@85: * $Id: stream.c,v 1.12 2004/02/05 09:02:39 rob Exp $ cannam@85: */ cannam@85: cannam@85: # ifdef HAVE_CONFIG_H cannam@85: # include "config.h" cannam@85: # endif cannam@85: cannam@85: # include "global.h" cannam@85: cannam@85: # include cannam@85: cannam@85: # include "bit.h" cannam@85: # include "stream.h" cannam@85: cannam@85: /* cannam@85: * NAME: stream->init() cannam@85: * DESCRIPTION: initialize stream struct cannam@85: */ cannam@85: void mad_stream_init(struct mad_stream *stream) cannam@85: { cannam@85: stream->buffer = 0; cannam@85: stream->bufend = 0; cannam@85: stream->skiplen = 0; cannam@85: cannam@85: stream->sync = 0; cannam@85: stream->freerate = 0; cannam@85: cannam@85: stream->this_frame = 0; cannam@85: stream->next_frame = 0; cannam@85: mad_bit_init(&stream->ptr, 0); cannam@85: cannam@85: mad_bit_init(&stream->anc_ptr, 0); cannam@85: stream->anc_bitlen = 0; cannam@85: cannam@85: stream->main_data = 0; cannam@85: stream->md_len = 0; cannam@85: cannam@85: stream->options = 0; cannam@85: stream->error = MAD_ERROR_NONE; cannam@85: } cannam@85: cannam@85: /* cannam@85: * NAME: stream->finish() cannam@85: * DESCRIPTION: deallocate any dynamic memory associated with stream cannam@85: */ cannam@85: void mad_stream_finish(struct mad_stream *stream) cannam@85: { cannam@85: if (stream->main_data) { cannam@85: free(stream->main_data); cannam@85: stream->main_data = 0; cannam@85: } cannam@85: cannam@85: mad_bit_finish(&stream->anc_ptr); cannam@85: mad_bit_finish(&stream->ptr); cannam@85: } cannam@85: cannam@85: /* cannam@85: * NAME: stream->buffer() cannam@85: * DESCRIPTION: set stream buffer pointers cannam@85: */ cannam@85: void mad_stream_buffer(struct mad_stream *stream, cannam@85: unsigned char const *buffer, unsigned long length) cannam@85: { cannam@85: stream->buffer = buffer; cannam@85: stream->bufend = buffer + length; cannam@85: cannam@85: stream->this_frame = buffer; cannam@85: stream->next_frame = buffer; cannam@85: cannam@85: stream->sync = 1; cannam@85: cannam@85: mad_bit_init(&stream->ptr, buffer); cannam@85: } cannam@85: cannam@85: /* cannam@85: * NAME: stream->skip() cannam@85: * DESCRIPTION: arrange to skip bytes before the next frame cannam@85: */ cannam@85: void mad_stream_skip(struct mad_stream *stream, unsigned long length) cannam@85: { cannam@85: stream->skiplen += length; cannam@85: } cannam@85: cannam@85: /* cannam@85: * NAME: stream->sync() cannam@85: * DESCRIPTION: locate the next stream sync word cannam@85: */ cannam@85: int mad_stream_sync(struct mad_stream *stream) cannam@85: { cannam@85: register unsigned char const *ptr, *end; cannam@85: cannam@85: ptr = mad_bit_nextbyte(&stream->ptr); cannam@85: end = stream->bufend; cannam@85: cannam@85: while (ptr < end - 1 && cannam@85: !(ptr[0] == 0xff && (ptr[1] & 0xe0) == 0xe0)) cannam@85: ++ptr; cannam@85: cannam@85: if (end - ptr < MAD_BUFFER_GUARD) cannam@85: return -1; cannam@85: cannam@85: mad_bit_init(&stream->ptr, ptr); cannam@85: cannam@85: return 0; cannam@85: } cannam@85: cannam@85: /* cannam@85: * NAME: stream->errorstr() cannam@85: * DESCRIPTION: return a string description of the current error condition cannam@85: */ cannam@85: char const *mad_stream_errorstr(struct mad_stream const *stream) cannam@85: { cannam@85: switch (stream->error) { cannam@85: case MAD_ERROR_NONE: return "no error"; cannam@85: cannam@85: case MAD_ERROR_BUFLEN: return "input buffer too small (or EOF)"; cannam@85: case MAD_ERROR_BUFPTR: return "invalid (null) buffer pointer"; cannam@85: cannam@85: case MAD_ERROR_NOMEM: return "not enough memory"; cannam@85: cannam@85: case MAD_ERROR_LOSTSYNC: return "lost synchronization"; cannam@85: case MAD_ERROR_BADLAYER: return "reserved header layer value"; cannam@85: case MAD_ERROR_BADBITRATE: return "forbidden bitrate value"; cannam@85: case MAD_ERROR_BADSAMPLERATE: return "reserved sample frequency value"; cannam@85: case MAD_ERROR_BADEMPHASIS: return "reserved emphasis value"; cannam@85: cannam@85: case MAD_ERROR_BADCRC: return "CRC check failed"; cannam@85: case MAD_ERROR_BADBITALLOC: return "forbidden bit allocation value"; cannam@85: case MAD_ERROR_BADSCALEFACTOR: return "bad scalefactor index"; cannam@85: case MAD_ERROR_BADMODE: return "bad bitrate/mode combination"; cannam@85: case MAD_ERROR_BADFRAMELEN: return "bad frame length"; cannam@85: case MAD_ERROR_BADBIGVALUES: return "bad big_values count"; cannam@85: case MAD_ERROR_BADBLOCKTYPE: return "reserved block_type"; cannam@85: case MAD_ERROR_BADSCFSI: return "bad scalefactor selection info"; cannam@85: case MAD_ERROR_BADDATAPTR: return "bad main_data_begin pointer"; cannam@85: case MAD_ERROR_BADPART3LEN: return "bad audio data length"; cannam@85: case MAD_ERROR_BADHUFFTABLE: return "bad Huffman table select"; cannam@85: case MAD_ERROR_BADHUFFDATA: return "Huffman data overrun"; cannam@85: case MAD_ERROR_BADSTEREO: return "incompatible block_type for JS"; cannam@85: } cannam@85: cannam@85: return 0; cannam@85: }