96 lines
3 KiB
C
96 lines
3 KiB
C
/* Copyright (c) 2001-2008 Timothy B. Terriberry
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Copyright (c) 2008-2009 Xiph.Org Foundation */
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/*
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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- Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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- Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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- Neither the name of the Xiph.org Foundation nor the names of its
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contributors may be used to endorse or promote products derived from
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this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR
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CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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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 <stddef.h>
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#include "entdec.h"
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#include "os_support.h"
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#include "arch.h"
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void ec_byte_readinit(ec_byte_buffer *_b,unsigned char *_buf,ec_uint32 _bytes){
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_b->buf=_b->ptr=_buf;
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_b->storage=_bytes;
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_b->end_ptr=_b->buf+_bytes-1;
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}
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unsigned char ec_byte_look_at_end(ec_byte_buffer *_b){
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celt_assert2 (_b->end_ptr >= _b->buf, "Trying to read raw bits before the beginning of the stream");
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return *(_b->end_ptr--);
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}
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void ec_byte_adv1(ec_byte_buffer *_b){
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_b->ptr++;
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}
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int ec_byte_read1(ec_byte_buffer *_b){
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ptrdiff_t endbyte;
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endbyte=_b->ptr-_b->buf;
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if(endbyte>=_b->storage)return -1;
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else return *(_b->ptr++);
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}
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ec_uint32 ec_dec_uint(ec_dec *_this,ec_uint32 _ft){
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unsigned ft;
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unsigned s;
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int ftb;
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/*In order to optimize EC_ILOG(), it is undefined for the value 0.*/
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celt_assert(_ft>1);
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_ft--;
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ftb=EC_ILOG(_ft);
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if(ftb>EC_UNIT_BITS){
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ec_uint32 t;
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ftb-=EC_UNIT_BITS;
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ft=(unsigned)(_ft>>ftb)+1;
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s=ec_decode(_this,ft);
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ec_dec_update(_this,s,s+1,ft);
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t=s;
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t = t<<ftb|ec_dec_bits(_this,ftb&(1<<ftb)-1);
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if (t>_ft)
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{
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_this->error |= 1;
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t = _ft;
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}
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return t;
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} else {
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_ft++;
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s=ec_decode(_this,(unsigned)_ft);
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ec_dec_update(_this,s,s+1,(unsigned)_ft);
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return s;
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}
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}
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int ec_dec_get_error(ec_dec *_this)
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{
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return _this->error || (ec_dec_tell(_this,0) > 8*_this->buf->storage);
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}
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