mirror of
https://gitlab.winehq.org/wine/wine-gecko.git
synced 2024-09-13 09:24:08 -07:00
a35bcd032f
Update files to match the opus-1.0.0 source release. This corresponds to the spec implementation included in RFC 6716. Changes from the previous in-tree version (draft-12): - Add extern "C" protection on opus_multistream.h. - Align to sizeof(void*) instead of 4 bytes. - Copyright header updates for IETF publication. - Minor documentation and whitespace fixes.
98 lines
3.3 KiB
C
98 lines
3.3 KiB
C
/* Copyright (c) 2001-2012 IETF Trust, Timothy B. Terriberry. All rights reserved.
|
|
*/
|
|
/*
|
|
|
|
This file is extracted from RFC6716. Please see that RFC for additional
|
|
information.
|
|
|
|
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.
|
|
|
|
- Neither the name of Internet Society, IETF or IETF Trust, nor the
|
|
names of specific contributors, may be used to endorse or promote
|
|
products derived from this software without specific prior written
|
|
permission.
|
|
|
|
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 "entcode.h"
|
|
#include "arch.h"
|
|
|
|
#if !defined(EC_CLZ)
|
|
int ec_ilog(opus_uint32 _v){
|
|
/*On a Pentium M, this branchless version tested as the fastest on
|
|
1,000,000,000 random 32-bit integers, edging out a similar version with
|
|
branches, and a 256-entry LUT version.*/
|
|
int ret;
|
|
int m;
|
|
ret=!!_v;
|
|
m=!!(_v&0xFFFF0000)<<4;
|
|
_v>>=m;
|
|
ret|=m;
|
|
m=!!(_v&0xFF00)<<3;
|
|
_v>>=m;
|
|
ret|=m;
|
|
m=!!(_v&0xF0)<<2;
|
|
_v>>=m;
|
|
ret|=m;
|
|
m=!!(_v&0xC)<<1;
|
|
_v>>=m;
|
|
ret|=m;
|
|
ret+=!!(_v&0x2);
|
|
return ret;
|
|
}
|
|
#endif
|
|
|
|
opus_uint32 ec_tell_frac(ec_ctx *_this){
|
|
opus_uint32 nbits;
|
|
opus_uint32 r;
|
|
int l;
|
|
int i;
|
|
/*To handle the non-integral number of bits still left in the encoder/decoder
|
|
state, we compute the worst-case number of bits of val that must be
|
|
encoded to ensure that the value is inside the range for any possible
|
|
subsequent bits.
|
|
The computation here is independent of val itself (the decoder does not
|
|
even track that value), even though the real number of bits used after
|
|
ec_enc_done() may be 1 smaller if rng is a power of two and the
|
|
corresponding trailing bits of val are all zeros.
|
|
If we did try to track that special case, then coding a value with a
|
|
probability of 1/(1<<n) might sometimes appear to use more than n bits.
|
|
This may help explain the surprising result that a newly initialized
|
|
encoder or decoder claims to have used 1 bit.*/
|
|
nbits=_this->nbits_total<<BITRES;
|
|
l=EC_ILOG(_this->rng);
|
|
r=_this->rng>>(l-16);
|
|
for(i=BITRES;i-->0;){
|
|
int b;
|
|
r=r*r>>15;
|
|
b=(int)(r>>16);
|
|
l=l<<1|b;
|
|
r>>=b;
|
|
}
|
|
return nbits-l;
|
|
}
|