ffmpeg / libavutil / intfloat_readwrite.c @ 699b3f99
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/*


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* portable IEEE float/double read/write functions

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*

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* Copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>

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*

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* This file is part of FFmpeg.

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*

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* FFmpeg is free software; you can redistribute it and/or

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* modify it under the terms of the GNU Lesser General Public

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* License as published by the Free Software Foundation; either

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* version 2.1 of the License, or (at your option) any later version.

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*

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* FFmpeg is distributed in the hope that it will be useful,

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* but WITHOUT ANY WARRANTY; without even the implied warranty of

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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

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* Lesser General Public License for more details.

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*

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* You should have received a copy of the GNU Lesser General Public

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* License along with FFmpeg; if not, write to the Free Software

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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 021101301 USA

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*/

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/**

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* @file intfloat_readwrite.c

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* Portable IEEE float/double read/write functions.

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*/

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#include "common.h" 
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#include "intfloat_readwrite.h" 
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double av_int2dbl(int64_t v){

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if(v+v > 0xFFEULL<<52) 
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return 0.0/0.0; 
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return ldexp(((v&((1LL<<52)1)) + (1LL<<52)) * (v>>631), (v>>52&0x7FF)1075); 
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} 
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float av_int2flt(int32_t v){

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if(v+v > 0xFF000000U) 
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return 0.0/0.0; 
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return ldexp(((v&0x7FFFFF) + (1<<23)) * (v>>311), (v>>23&0xFF)150); 
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} 
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double av_ext2dbl(const AVExtFloat ext){ 
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uint64_t m = 0;

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int e, i;

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for (i = 0; i < 8; i++) 
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m = (m<<8) + ext.mantissa[i];

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e = (((int)ext.exponent[0]&0x7f)<<8)  ext.exponent[1]; 
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if (e == 0x7fff && m) 
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return 0.0/0.0; 
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e = 16383 + 63; /* In IEEE 80 bits, the whole (i.e. 1.xxxx) 
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* mantissa bit is written as opposed to the

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* single and double precision formats */

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if (ext.exponent[0]&0x80) 
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m= m; 
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return ldexp(m, e);

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} 
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int64_t av_dbl2int(double d){

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int e;

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if ( !d) return 0; 
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else if(dd) return 0x7FF0000000000000LL + ((int64_t)(d<0)<<63) + (d!=d); 
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d= frexp(d, &e); 
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return (int64_t)(d<0)<<63  (e+1022LL)<<52  (int64_t)((fabs(d)0.5)*(1LL<<53)); 
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} 
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int32_t av_flt2int(float d){

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int e;

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if ( !d) return 0; 
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else if(dd) return 0x7F800000 + ((d<0)<<31) + (d!=d); 
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d= frexp(d, &e); 
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return (d<0)<<31  (e+126)<<23  (int64_t)((fabs(d)0.5)*(1<<24)); 
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} 
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AVExtFloat av_dbl2ext(double d){

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struct AVExtFloat ext= {{0}}; 
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int e, i; double f; uint64_t m; 
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f = fabs(frexp(d, &e)); 
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if (f >= 0.5 && f < 1) { 
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e += 16382;

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ext.exponent[0] = e>>8; 
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ext.exponent[1] = e;

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m = (uint64_t)ldexp(f, 64);

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for (i=0; i < 8; i++) 
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ext.mantissa[i] = m>>(56(i<<3)); 
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} else if (f != 0.0) { 
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ext.exponent[0] = 0x7f; ext.exponent[1] = 0xff; 
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if (f != 1/0.0) 
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ext.mantissa[0] = ~0; 
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} 
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if (d < 0) 
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ext.exponent[0] = 0x80; 
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return ext;

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} 
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