/src/opus/celt/entenc.c

Source (jump to first uncovered line)
/* 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 OPUS_INLINE 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=celt_udiv(_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_icdf16(ec_enc *_this,int _s,const opus_uint16 *_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;
      }
    }
  }
}

Coverage Report

Created: 2024-09-06 07:53

Line	Count	Source (jump to first uncovered line)
1		/* Copyright (c) 2001-2011 Timothy B. Terriberry
2		Copyright (c) 2008-2009 Xiph.Org Foundation */
3		/*
4		Redistribution and use in source and binary forms, with or without
5		modification, are permitted provided that the following conditions
6		are met:
7
8		- Redistributions of source code must retain the above copyright
9		notice, this list of conditions and the following disclaimer.
10
11		- Redistributions in binary form must reproduce the above copyright
12		notice, this list of conditions and the following disclaimer in the
13		documentation and/or other materials provided with the distribution.
14
15		THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16		``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17		LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
18		A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
19		OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
20		EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21		PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
22		PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
23		LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
24		NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
25		SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26		*/
27
28		#if defined(HAVE_CONFIG_H)
29		# include "config.h"
30		#endif
31		#include "os_support.h"
32		#include "arch.h"
33		#include "entenc.h"
34		#include "mfrngcod.h"
35
36		/*A range encoder.
37		See entdec.c and the references for implementation details \cite{Mar79,MNW98}.
38
39		@INPROCEEDINGS{Mar79,
40		author="Martin, G.N.N.",
41		title="Range encoding: an algorithm for removing redundancy from a digitised
42		message",
43		booktitle="Video \& Data Recording Conference",
44		year=1979,
45		address="Southampton",
46		month=Jul
47		}
48		@ARTICLE{MNW98,
49		author="Alistair Moffat and Radford Neal and Ian H. Witten",
50		title="Arithmetic Coding Revisited",
51		journal="{ACM} Transactions on Information Systems",
52		year=1998,
53		volume=16,
54		number=3,
55		pages="256--294",
56		month=Jul,
57		URL="http://www.stanford.edu/class/ee398/handouts/papers/Moffat98ArithmCoding.pdf"
58		}*/
59
60	0	static int ec_write_byte(ec_enc *_this,unsigned _value){
61	0	if(_this->offs+_this->end_offs>=_this->storage)return -1;
62	0	_this->buf[_this->offs++]=(unsigned char)_value;
63	0	return 0;
64	0	}
65
66	0	static int ec_write_byte_at_end(ec_enc *_this,unsigned _value){
67	0	if(_this->offs+_this->end_offs>=_this->storage)return -1;
68	0	_this->buf[_this->storage-++(_this->end_offs)]=(unsigned char)_value;
69	0	return 0;
70	0	}
71
72		/*Outputs a symbol, with a carry bit.
73		If there is a potential to propagate a carry over several symbols, they are
74		buffered until it can be determined whether or not an actual carry will
75		occur.
76		If the counter for the buffered symbols overflows, then the stream becomes
77		undecodable.
78		This gives a theoretical limit of a few billion symbols in a single packet on
79		32-bit systems.
80		The alternative is to truncate the range in order to force a carry, but
81		requires similar carry tracking in the decoder, needlessly slowing it down.*/
82	0	static void ec_enc_carry_out(ec_enc *_this,int _c){
83	0	if(_c!=EC_SYM_MAX){
84		/No further carry propagation possible, flush buffer./
85	0	int carry;
86	0	carry=_c>>EC_SYM_BITS;
87		/*Don't output a byte on the first write.
88		This compare should be taken care of by branch-prediction thereafter.*/
89	0	if(_this->rem>=0)_this->error\|=ec_write_byte(_this,_this->rem+carry);
90	0	if(_this->ext>0){
91	0	unsigned sym;
92	0	sym=(EC_SYM_MAX+carry)&EC_SYM_MAX;
93	0	do _this->error\|=ec_write_byte(_this,sym);
94	0	while(--(_this->ext)>0);
95	0	}
96	0	_this->rem=_c&EC_SYM_MAX;
97	0	}
98	0	else _this->ext++;
99	0	}
100
101	0	static OPUS_INLINE void ec_enc_normalize(ec_enc *_this){
102		/If the range is too small, output some bits and rescale it./
103	0	while(_this->rng<=EC_CODE_BOT){
104	0	ec_enc_carry_out(_this,(int)(_this->val>>EC_CODE_SHIFT));
105		/Move the next-to-high-order symbol into the high-order position./
106	0	_this->val=(_this->val<<EC_SYM_BITS)&(EC_CODE_TOP-1);
107	0	_this->rng<<=EC_SYM_BITS;
108	0	_this->nbits_total+=EC_SYM_BITS;
109	0	}
110	0	}
111
112	0	void ec_enc_init(ec_enc _this,unsigned char _buf,opus_uint32 _size){
113	0	_this->buf=_buf;
114	0	_this->end_offs=0;
115	0	_this->end_window=0;
116	0	_this->nend_bits=0;
117		/This is the offset from which ec_tell() will subtract partial bits./
118	0	_this->nbits_total=EC_CODE_BITS+1;
119	0	_this->offs=0;
120	0	_this->rng=EC_CODE_TOP;
121	0	_this->rem=-1;
122	0	_this->val=0;
123	0	_this->ext=0;
124	0	_this->storage=_size;
125	0	_this->error=0;
126	0	}
127
128	0	void ec_encode(ec_enc *_this,unsigned _fl,unsigned _fh,unsigned _ft){
129	0	opus_uint32 r;
130	0	r=celt_udiv(_this->rng,_ft);
131	0	if(_fl>0){
132	0	_this->val+=_this->rng-IMUL32(r,(_ft-_fl));
133	0	_this->rng=IMUL32(r,(_fh-_fl));
134	0	}
135	0	else _this->rng-=IMUL32(r,(_ft-_fh));
136	0	ec_enc_normalize(_this);
137	0	}
138
139	0	void ec_encode_bin(ec_enc *_this,unsigned _fl,unsigned _fh,unsigned _bits){
140	0	opus_uint32 r;
141	0	r=_this->rng>>_bits;
142	0	if(_fl>0){
143	0	_this->val+=_this->rng-IMUL32(r,((1U<<_bits)-_fl));
144	0	_this->rng=IMUL32(r,(_fh-_fl));
145	0	}
146	0	else _this->rng-=IMUL32(r,((1U<<_bits)-_fh));
147	0	ec_enc_normalize(_this);
148	0	}
149
150		/The probability of having a "one" is 1/(1<<_logp)./
151	0	void ec_enc_bit_logp(ec_enc *_this,int _val,unsigned _logp){
152	0	opus_uint32 r;
153	0	opus_uint32 s;
154	0	opus_uint32 l;
155	0	r=_this->rng;
156	0	l=_this->val;
157	0	s=r>>_logp;
158	0	r-=s;
159	0	if(_val)_this->val=l+r;
160	0	_this->rng=_val?s:r;
161	0	ec_enc_normalize(_this);
162	0	}
163
164	0	void ec_enc_icdf(ec_enc _this,int _s,const unsigned char _icdf,unsigned _ftb){
165	0	opus_uint32 r;
166	0	r=_this->rng>>_ftb;
167	0	if(_s>0){
168	0	_this->val+=_this->rng-IMUL32(r,_icdf[_s-1]);
169	0	_this->rng=IMUL32(r,_icdf[_s-1]-_icdf[_s]);
170	0	}
171	0	else _this->rng-=IMUL32(r,_icdf[_s]);
172	0	ec_enc_normalize(_this);
173	0	}
174
175	0	void ec_enc_icdf16(ec_enc _this,int _s,const opus_uint16 _icdf,unsigned _ftb){
176	0	opus_uint32 r;
177	0	r=_this->rng>>_ftb;
178	0	if(_s>0){
179	0	_this->val+=_this->rng-IMUL32(r,_icdf[_s-1]);
180	0	_this->rng=IMUL32(r,_icdf[_s-1]-_icdf[_s]);
181	0	}
182	0	else _this->rng-=IMUL32(r,_icdf[_s]);
183	0	ec_enc_normalize(_this);
184	0	}
185
186	0	void ec_enc_uint(ec_enc *_this,opus_uint32 _fl,opus_uint32 _ft){
187	0	unsigned ft;
188	0	unsigned fl;
189	0	int ftb;
190		/In order to optimize EC_ILOG(), it is undefined for the value 0./
191	0	celt_assert(_ft>1);
192	0	_ft--;
193	0	ftb=EC_ILOG(_ft);
194	0	if(ftb>EC_UINT_BITS){
195	0	ftb-=EC_UINT_BITS;
196	0	ft=(_ft>>ftb)+1;
197	0	fl=(unsigned)(_fl>>ftb);
198	0	ec_encode(_this,fl,fl+1,ft);
199	0	ec_enc_bits(_this,_fl&(((opus_uint32)1<<ftb)-1U),ftb);
200	0	}
201	0	else ec_encode(_this,_fl,_fl+1,_ft+1);
202	0	}
203
204	0	void ec_enc_bits(ec_enc *_this,opus_uint32 _fl,unsigned _bits){
205	0	ec_window window;
206	0	int used;
207	0	window=_this->end_window;
208	0	used=_this->nend_bits;
209	0	celt_assert(_bits>0);
210	0	if(used+_bits>EC_WINDOW_SIZE){
211	0	do{
212	0	_this->error\|=ec_write_byte_at_end(_this,(unsigned)window&EC_SYM_MAX);
213	0	window>>=EC_SYM_BITS;
214	0	used-=EC_SYM_BITS;
215	0	}
216	0	while(used>=EC_SYM_BITS);
217	0	}
218	0	window\|=(ec_window)_fl<<used;
219	0	used+=_bits;
220	0	_this->end_window=window;
221	0	_this->nend_bits=used;
222	0	_this->nbits_total+=_bits;
223	0	}
224
225	0	void ec_enc_patch_initial_bits(ec_enc *_this,unsigned _val,unsigned _nbits){
226	0	int shift;
227	0	unsigned mask;
228	0	celt_assert(_nbits<=EC_SYM_BITS);
229	0	shift=EC_SYM_BITS-_nbits;
230	0	mask=((1<<_nbits)-1)<<shift;
231	0	if(_this->offs>0){
232		/The first byte has been finalized./
233	0	_this->buf[0]=(unsigned char)((_this->buf[0]&~mask)\|_val<<shift);
234	0	}
235	0	else if(_this->rem>=0){
236		/The first byte is still awaiting carry propagation./
237	0	_this->rem=(_this->rem&~mask)\|_val<<shift;
238	0	}
239	0	else if(_this->rng<=(EC_CODE_TOP>>_nbits)){
240		/The renormalization loop has never been run./
241	0	_this->val=(_this->val&~((opus_uint32)mask<<EC_CODE_SHIFT))\|
242	0	(opus_uint32)_val<<(EC_CODE_SHIFT+shift);
243	0	}
244		/The encoder hasn't even encoded _nbits of data yet./
245	0	else _this->error=-1;
246	0	}
247
248	0	void ec_enc_shrink(ec_enc *_this,opus_uint32 _size){
249	0	celt_assert(_this->offs+_this->end_offs<=_size);
250	0	OPUS_MOVE(_this->buf+_size-_this->end_offs,
251	0	_this->buf+_this->storage-_this->end_offs,_this->end_offs);
252	0	_this->storage=_size;
253	0	}
254
255	0	void ec_enc_done(ec_enc *_this){
256	0	ec_window window;
257	0	int used;
258	0	opus_uint32 msk;
259	0	opus_uint32 end;
260	0	int l;
261		/*We output the minimum number of bits that ensures that the symbols encoded
262		thus far will be decoded correctly regardless of the bits that follow.*/
263	0	l=EC_CODE_BITS-EC_ILOG(_this->rng);
264	0	msk=(EC_CODE_TOP-1)>>l;
265	0	end=(_this->val+msk)&~msk;
266	0	if((end\|msk)>=_this->val+_this->rng){
267	0	l++;
268	0	msk>>=1;
269	0	end=(_this->val+msk)&~msk;
270	0	}
271	0	while(l>0){
272	0	ec_enc_carry_out(_this,(int)(end>>EC_CODE_SHIFT));
273	0	end=(end<<EC_SYM_BITS)&(EC_CODE_TOP-1);
274	0	l-=EC_SYM_BITS;
275	0	}
276		/If we have a buffered byte flush it into the output buffer./
277	0	if(_this->rem>=0\|\|_this->ext>0)ec_enc_carry_out(_this,0);
278		/If we have buffered extra bits, flush them as well./
279	0	window=_this->end_window;
280	0	used=_this->nend_bits;
281	0	while(used>=EC_SYM_BITS){
282	0	_this->error\|=ec_write_byte_at_end(_this,(unsigned)window&EC_SYM_MAX);
283	0	window>>=EC_SYM_BITS;
284	0	used-=EC_SYM_BITS;
285	0	}
286		/Clear any excess space and add any remaining extra bits to the last byte./
287	0	if(!_this->error){
288	0	OPUS_CLEAR(_this->buf+_this->offs,
289	0	_this->storage-_this->offs-_this->end_offs);
290	0	if(used>0){
291		/If there's no range coder data at all, give up./
292	0	if(_this->end_offs>=_this->storage)_this->error=-1;
293	0	else{
294	0	l=-l;
295		/*If we've busted, don't add too many extra bits to the last byte; it
296		would corrupt the range coder data, and that's more important.*/
297	0	if(_this->offs+_this->end_offs>=_this->storage&&l<used){
298	0	window&=(1<<l)-1;
299	0	_this->error=-1;
300	0	}
301	0	_this->buf[_this->storage-_this->end_offs-1]\|=(unsigned char)window;
302	0	}
303	0	}
304	0	}
305	0	}