mirror of https://git.ffmpeg.org/ffmpeg.git
99 lines
2.9 KiB
C
99 lines
2.9 KiB
C
/*
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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 Libav.
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*
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* Libav 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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* Libav 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 Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* portable IEEE float/double read/write functions
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*/
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#include <stdint.h>
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#include "mathematics.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 NAN;
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return ldexp(((v&((1LL<<52)-1)) + (1LL<<52)) * (v>>63|1), (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 NAN;
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return ldexp(((v&0x7FFFFF) + (1<<23)) * (v>>31|1), (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 NAN;
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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(d-d) 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(d-d) 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 != INFINITY)
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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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