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diff --git a/src/opus-1.1/celt/entenc.c b/src/opus-1.1/celt/entenc.c
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-/* Copyright (c) 2001-2011 Timothy B. Terriberry
- Copyright (c) 2008-2009 Xiph.Org Foundation */
-/*
- Redistribution and use in source and binary forms, with or without
- modification, are permitted provided that the following conditions
- are met:
-
- - Redistributions of source code must retain the above copyright
- notice, this list of conditions and the following disclaimer.
-
- - Redistributions in binary form must reproduce the above copyright
- notice, this list of conditions and the following disclaimer in the
- documentation and/or other materials provided with the distribution.
-
- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
- OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
- EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
- PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
- PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
- LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
- NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
- SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-*/
-
-#if defined(HAVE_CONFIG_H)
-# include "config.h"
-#endif
-#include "os_support.h"
-#include "arch.h"
-#include "entenc.h"
-#include "mfrngcod.h"
-
-/*A range encoder.
- See entdec.c and the references for implementation details \cite{Mar79,MNW98}.
-
- @INPROCEEDINGS{Mar79,
- author="Martin, G.N.N.",
- title="Range encoding: an algorithm for removing redundancy from a digitised
- message",
- booktitle="Video \& Data Recording Conference",
- year=1979,
- address="Southampton",
- month=Jul
- }
- @ARTICLE{MNW98,
- author="Alistair Moffat and Radford Neal and Ian H. Witten",
- title="Arithmetic Coding Revisited",
- journal="{ACM} Transactions on Information Systems",
- year=1998,
- volume=16,
- number=3,
- pages="256--294",
- month=Jul,
- URL="http://www.stanford.edu/class/ee398/handouts/papers/Moffat98ArithmCoding.pdf"
- }*/
-
-static int ec_write_byte(ec_enc *_this,unsigned _value){
- if(_this->offs+_this->end_offs>=_this->storage)return -1;
- _this->buf[_this->offs++]=(unsigned char)_value;
- return 0;
-}
-
-static int ec_write_byte_at_end(ec_enc *_this,unsigned _value){
- if(_this->offs+_this->end_offs>=_this->storage)return -1;
- _this->buf[_this->storage-++(_this->end_offs)]=(unsigned char)_value;
- return 0;
-}
-
-/*Outputs a symbol, with a carry bit.
- If there is a potential to propagate a carry over several symbols, they are
- buffered until it can be determined whether or not an actual carry will
- occur.
- If the counter for the buffered symbols overflows, then the stream becomes
- undecodable.
- This gives a theoretical limit of a few billion symbols in a single packet on
- 32-bit systems.
- The alternative is to truncate the range in order to force a carry, but
- requires similar carry tracking in the decoder, needlessly slowing it down.*/
-static void ec_enc_carry_out(ec_enc *_this,int _c){
- if(_c!=EC_SYM_MAX){
- /*No further carry propagation possible, flush buffer.*/
- int carry;
- carry=_c>>EC_SYM_BITS;
- /*Don't output a byte on the first write.
- This compare should be taken care of by branch-prediction thereafter.*/
- if(_this->rem>=0)_this->error|=ec_write_byte(_this,_this->rem+carry);
- if(_this->ext>0){
- unsigned sym;
- sym=(EC_SYM_MAX+carry)&EC_SYM_MAX;
- do _this->error|=ec_write_byte(_this,sym);
- while(--(_this->ext)>0);
- }
- _this->rem=_c&EC_SYM_MAX;
- }
- else _this->ext++;
-}
-
-static void ec_enc_normalize(ec_enc *_this){
- /*If the range is too small, output some bits and rescale it.*/
- while(_this->rng<=EC_CODE_BOT){
- ec_enc_carry_out(_this,(int)(_this->val>>EC_CODE_SHIFT));
- /*Move the next-to-high-order symbol into the high-order position.*/
- _this->val=(_this->val<<EC_SYM_BITS)&(EC_CODE_TOP-1);
- _this->rng<<=EC_SYM_BITS;
- _this->nbits_total+=EC_SYM_BITS;
- }
-}
-
-void ec_enc_init(ec_enc *_this,unsigned char *_buf,opus_uint32 _size){
- _this->buf=_buf;
- _this->end_offs=0;
- _this->end_window=0;
- _this->nend_bits=0;
- /*This is the offset from which ec_tell() will subtract partial bits.*/
- _this->nbits_total=EC_CODE_BITS+1;
- _this->offs=0;
- _this->rng=EC_CODE_TOP;
- _this->rem=-1;
- _this->val=0;
- _this->ext=0;
- _this->storage=_size;
- _this->error=0;
-}
-
-void ec_encode(ec_enc *_this,unsigned _fl,unsigned _fh,unsigned _ft){
- opus_uint32 r;
- r=_this->rng/_ft;
- if(_fl>0){
- _this->val+=_this->rng-IMUL32(r,(_ft-_fl));
- _this->rng=IMUL32(r,(_fh-_fl));
- }
- else _this->rng-=IMUL32(r,(_ft-_fh));
- ec_enc_normalize(_this);
-}
-
-void ec_encode_bin(ec_enc *_this,unsigned _fl,unsigned _fh,unsigned _bits){
- opus_uint32 r;
- r=_this->rng>>_bits;
- if(_fl>0){
- _this->val+=_this->rng-IMUL32(r,((1U<<_bits)-_fl));
- _this->rng=IMUL32(r,(_fh-_fl));
- }
- else _this->rng-=IMUL32(r,((1U<<_bits)-_fh));
- ec_enc_normalize(_this);
-}
-
-/*The probability of having a "one" is 1/(1<<_logp).*/
-void ec_enc_bit_logp(ec_enc *_this,int _val,unsigned _logp){
- opus_uint32 r;
- opus_uint32 s;
- opus_uint32 l;
- r=_this->rng;
- l=_this->val;
- s=r>>_logp;
- r-=s;
- if(_val)_this->val=l+r;
- _this->rng=_val?s:r;
- ec_enc_normalize(_this);
-}
-
-void ec_enc_icdf(ec_enc *_this,int _s,const unsigned char *_icdf,unsigned _ftb){
- opus_uint32 r;
- r=_this->rng>>_ftb;
- if(_s>0){
- _this->val+=_this->rng-IMUL32(r,_icdf[_s-1]);
- _this->rng=IMUL32(r,_icdf[_s-1]-_icdf[_s]);
- }
- else _this->rng-=IMUL32(r,_icdf[_s]);
- ec_enc_normalize(_this);
-}
-
-void ec_enc_uint(ec_enc *_this,opus_uint32 _fl,opus_uint32 _ft){
- unsigned ft;
- unsigned fl;
- int ftb;
- /*In order to optimize EC_ILOG(), it is undefined for the value 0.*/
- celt_assert(_ft>1);
- _ft--;
- ftb=EC_ILOG(_ft);
- if(ftb>EC_UINT_BITS){
- ftb-=EC_UINT_BITS;
- ft=(_ft>>ftb)+1;
- fl=(unsigned)(_fl>>ftb);
- ec_encode(_this,fl,fl+1,ft);
- ec_enc_bits(_this,_fl&(((opus_uint32)1<<ftb)-1U),ftb);
- }
- else ec_encode(_this,_fl,_fl+1,_ft+1);
-}
-
-void ec_enc_bits(ec_enc *_this,opus_uint32 _fl,unsigned _bits){
- ec_window window;
- int used;
- window=_this->end_window;
- used=_this->nend_bits;
- celt_assert(_bits>0);
- if(used+_bits>EC_WINDOW_SIZE){
- do{
- _this->error|=ec_write_byte_at_end(_this,(unsigned)window&EC_SYM_MAX);
- window>>=EC_SYM_BITS;
- used-=EC_SYM_BITS;
- }
- while(used>=EC_SYM_BITS);
- }
- window|=(ec_window)_fl<<used;
- used+=_bits;
- _this->end_window=window;
- _this->nend_bits=used;
- _this->nbits_total+=_bits;
-}
-
-void ec_enc_patch_initial_bits(ec_enc *_this,unsigned _val,unsigned _nbits){
- int shift;
- unsigned mask;
- celt_assert(_nbits<=EC_SYM_BITS);
- shift=EC_SYM_BITS-_nbits;
- mask=((1<<_nbits)-1)<<shift;
- if(_this->offs>0){
- /*The first byte has been finalized.*/
- _this->buf[0]=(unsigned char)((_this->buf[0]&~mask)|_val<<shift);
- }
- else if(_this->rem>=0){
- /*The first byte is still awaiting carry propagation.*/
- _this->rem=(_this->rem&~mask)|_val<<shift;
- }
- else if(_this->rng<=(EC_CODE_TOP>>_nbits)){
- /*The renormalization loop has never been run.*/
- _this->val=(_this->val&~((opus_uint32)mask<<EC_CODE_SHIFT))|
- (opus_uint32)_val<<(EC_CODE_SHIFT+shift);
- }
- /*The encoder hasn't even encoded _nbits of data yet.*/
- else _this->error=-1;
-}
-
-void ec_enc_shrink(ec_enc *_this,opus_uint32 _size){
- celt_assert(_this->offs+_this->end_offs<=_size);
- OPUS_MOVE(_this->buf+_size-_this->end_offs,
- _this->buf+_this->storage-_this->end_offs,_this->end_offs);
- _this->storage=_size;
-}
-
-void ec_enc_done(ec_enc *_this){
- ec_window window;
- int used;
- opus_uint32 msk;
- opus_uint32 end;
- int l;
- /*We output the minimum number of bits that ensures that the symbols encoded
- thus far will be decoded correctly regardless of the bits that follow.*/
- l=EC_CODE_BITS-EC_ILOG(_this->rng);
- msk=(EC_CODE_TOP-1)>>l;
- end=(_this->val+msk)&~msk;
- if((end|msk)>=_this->val+_this->rng){
- l++;
- msk>>=1;
- end=(_this->val+msk)&~msk;
- }
- while(l>0){
- ec_enc_carry_out(_this,(int)(end>>EC_CODE_SHIFT));
- end=(end<<EC_SYM_BITS)&(EC_CODE_TOP-1);
- l-=EC_SYM_BITS;
- }
- /*If we have a buffered byte flush it into the output buffer.*/
- if(_this->rem>=0||_this->ext>0)ec_enc_carry_out(_this,0);
- /*If we have buffered extra bits, flush them as well.*/
- window=_this->end_window;
- used=_this->nend_bits;
- while(used>=EC_SYM_BITS){
- _this->error|=ec_write_byte_at_end(_this,(unsigned)window&EC_SYM_MAX);
- window>>=EC_SYM_BITS;
- used-=EC_SYM_BITS;
- }
- /*Clear any excess space and add any remaining extra bits to the last byte.*/
- if(!_this->error){
- OPUS_CLEAR(_this->buf+_this->offs,
- _this->storage-_this->offs-_this->end_offs);
- if(used>0){
- /*If there's no range coder data at all, give up.*/
- if(_this->end_offs>=_this->storage)_this->error=-1;
- else{
- l=-l;
- /*If we've busted, don't add too many extra bits to the last byte; it
- would corrupt the range coder data, and that's more important.*/
- if(_this->offs+_this->end_offs>=_this->storage&&l<used){
- window&=(1<<l)-1;
- _this->error=-1;
- }
- _this->buf[_this->storage-_this->end_offs-1]|=(unsigned char)window;
- }
- }
- }
-}
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