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Diffstat (limited to 'src/main/jni/opus/celt/entdec.c')
-rw-r--r-- | src/main/jni/opus/celt/entdec.c | 245 |
1 files changed, 0 insertions, 245 deletions
diff --git a/src/main/jni/opus/celt/entdec.c b/src/main/jni/opus/celt/entdec.c deleted file mode 100644 index 3c264685c..000000000 --- a/src/main/jni/opus/celt/entdec.c +++ /dev/null @@ -1,245 +0,0 @@ -/* 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. -*/ - -#ifdef HAVE_CONFIG_H -#include "config.h" -#endif - -#include <stddef.h> -#include "os_support.h" -#include "arch.h" -#include "entdec.h" -#include "mfrngcod.h" - -/*A range decoder. - This is an entropy decoder based upon \cite{Mar79}, which is itself a - rediscovery of the FIFO arithmetic code introduced by \cite{Pas76}. - It is very similar to arithmetic encoding, except that encoding is done with - digits in any base, instead of with bits, and so it is faster when using - larger bases (i.e.: a byte). - The author claims an average waste of $\frac{1}{2}\log_b(2b)$ bits, where $b$ - is the base, longer than the theoretical optimum, but to my knowledge there - is no published justification for this claim. - This only seems true when using near-infinite precision arithmetic so that - the process is carried out with no rounding errors. - - An excellent description of implementation details is available at - http://www.arturocampos.com/ac_range.html - A recent work \cite{MNW98} which proposes several changes to arithmetic - encoding for efficiency actually re-discovers many of the principles - behind range encoding, and presents a good theoretical analysis of them. - - End of stream is handled by writing out the smallest number of bits that - ensures that the stream will be correctly decoded regardless of the value of - any subsequent bits. - ec_tell() can be used to determine how many bits were needed to decode - all the symbols thus far; other data can be packed in the remaining bits of - the input buffer. - @PHDTHESIS{Pas76, - author="Richard Clark Pasco", - title="Source coding algorithms for fast data compression", - school="Dept. of Electrical Engineering, Stanford University", - address="Stanford, CA", - month=May, - year=1976 - } - @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/ee398a/handouts/papers/Moffat98ArithmCoding.pdf" - }*/ - -static int ec_read_byte(ec_dec *_this){ - return _this->offs<_this->storage?_this->buf[_this->offs++]:0; -} - -static int ec_read_byte_from_end(ec_dec *_this){ - return _this->end_offs<_this->storage? - _this->buf[_this->storage-++(_this->end_offs)]:0; -} - -/*Normalizes the contents of val and rng so that rng lies entirely in the - high-order symbol.*/ -static void ec_dec_normalize(ec_dec *_this){ - /*If the range is too small, rescale it and input some bits.*/ - while(_this->rng<=EC_CODE_BOT){ - int sym; - _this->nbits_total+=EC_SYM_BITS; - _this->rng<<=EC_SYM_BITS; - /*Use up the remaining bits from our last symbol.*/ - sym=_this->rem; - /*Read the next value from the input.*/ - _this->rem=ec_read_byte(_this); - /*Take the rest of the bits we need from this new symbol.*/ - sym=(sym<<EC_SYM_BITS|_this->rem)>>(EC_SYM_BITS-EC_CODE_EXTRA); - /*And subtract them from val, capped to be less than EC_CODE_TOP.*/ - _this->val=((_this->val<<EC_SYM_BITS)+(EC_SYM_MAX&~sym))&(EC_CODE_TOP-1); - } -} - -void ec_dec_init(ec_dec *_this,unsigned char *_buf,opus_uint32 _storage){ - _this->buf=_buf; - _this->storage=_storage; - _this->end_offs=0; - _this->end_window=0; - _this->nend_bits=0; - /*This is the offset from which ec_tell() will subtract partial bits. - The final value after the ec_dec_normalize() call will be the same as in - the encoder, but we have to compensate for the bits that are added there.*/ - _this->nbits_total=EC_CODE_BITS+1 - -((EC_CODE_BITS-EC_CODE_EXTRA)/EC_SYM_BITS)*EC_SYM_BITS; - _this->offs=0; - _this->rng=1U<<EC_CODE_EXTRA; - _this->rem=ec_read_byte(_this); - _this->val=_this->rng-1-(_this->rem>>(EC_SYM_BITS-EC_CODE_EXTRA)); - _this->error=0; - /*Normalize the interval.*/ - ec_dec_normalize(_this); -} - -unsigned ec_decode(ec_dec *_this,unsigned _ft){ - unsigned s; - _this->ext=_this->rng/_ft; - s=(unsigned)(_this->val/_this->ext); - return _ft-EC_MINI(s+1,_ft); -} - -unsigned ec_decode_bin(ec_dec *_this,unsigned _bits){ - unsigned s; - _this->ext=_this->rng>>_bits; - s=(unsigned)(_this->val/_this->ext); - return (1U<<_bits)-EC_MINI(s+1U,1U<<_bits); -} - -void ec_dec_update(ec_dec *_this,unsigned _fl,unsigned _fh,unsigned _ft){ - opus_uint32 s; - s=IMUL32(_this->ext,_ft-_fh); - _this->val-=s; - _this->rng=_fl>0?IMUL32(_this->ext,_fh-_fl):_this->rng-s; - ec_dec_normalize(_this); -} - -/*The probability of having a "one" is 1/(1<<_logp).*/ -int ec_dec_bit_logp(ec_dec *_this,unsigned _logp){ - opus_uint32 r; - opus_uint32 d; - opus_uint32 s; - int ret; - r=_this->rng; - d=_this->val; - s=r>>_logp; - ret=d<s; - if(!ret)_this->val=d-s; - _this->rng=ret?s:r-s; - ec_dec_normalize(_this); - return ret; -} - -int ec_dec_icdf(ec_dec *_this,const unsigned char *_icdf,unsigned _ftb){ - opus_uint32 r; - opus_uint32 d; - opus_uint32 s; - opus_uint32 t; - int ret; - s=_this->rng; - d=_this->val; - r=s>>_ftb; - ret=-1; - do{ - t=s; - s=IMUL32(r,_icdf[++ret]); - } - while(d<s); - _this->val=d-s; - _this->rng=t-s; - ec_dec_normalize(_this); - return ret; -} - -opus_uint32 ec_dec_uint(ec_dec *_this,opus_uint32 _ft){ - unsigned ft; - unsigned s; - 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){ - opus_uint32 t; - ftb-=EC_UINT_BITS; - ft=(unsigned)(_ft>>ftb)+1; - s=ec_decode(_this,ft); - ec_dec_update(_this,s,s+1,ft); - t=(opus_uint32)s<<ftb|ec_dec_bits(_this,ftb); - if(t<=_ft)return t; - _this->error=1; - return _ft; - } - else{ - _ft++; - s=ec_decode(_this,(unsigned)_ft); - ec_dec_update(_this,s,s+1,(unsigned)_ft); - return s; - } -} - -opus_uint32 ec_dec_bits(ec_dec *_this,unsigned _bits){ - ec_window window; - int available; - opus_uint32 ret; - window=_this->end_window; - available=_this->nend_bits; - if((unsigned)available<_bits){ - do{ - window|=(ec_window)ec_read_byte_from_end(_this)<<available; - available+=EC_SYM_BITS; - } - while(available<=EC_WINDOW_SIZE-EC_SYM_BITS); - } - ret=(opus_uint32)window&(((opus_uint32)1<<_bits)-1U); - window>>=_bits; - available-=_bits; - _this->end_window=window; - _this->nend_bits=available; - _this->nbits_total+=_bits; - return ret; -} |