1/* 2 * portable IEEE float/double read/write functions 3 * 4 * Copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at> 5 * 6 * This file is part of FFmpeg. 7 * 8 * FFmpeg is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU Lesser General Public 10 * License as published by the Free Software Foundation; either 11 * version 2.1 of the License, or (at your option) any later version. 12 * 13 * FFmpeg is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 16 * Lesser General Public License for more details. 17 * 18 * You should have received a copy of the GNU Lesser General Public 19 * License along with FFmpeg; if not, write to the Free Software 20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 21 */ 22 23/** 24 * @file 25 * portable IEEE float/double read/write functions 26 */ 27 28#include <stdint.h> 29#include "common.h" 30#include "mathematics.h" 31#include "intfloat_readwrite.h" 32#include "version.h" 33 34#if FF_API_INTFLOAT 35double av_int2dbl(int64_t v){ 36 if((uint64_t)v+v > 0xFFEULL<<52) 37 return NAN; 38 return ldexp(((v&((1LL<<52)-1)) + (1LL<<52)) * (v>>63|1), (v>>52&0x7FF)-1075); 39} 40 41float av_int2flt(int32_t v){ 42 if((uint32_t)v+v > 0xFF000000U) 43 return NAN; 44 return ldexp(((v&0x7FFFFF) + (1<<23)) * (v>>31|1), (v>>23&0xFF)-150); 45} 46 47double av_ext2dbl(const AVExtFloat ext){ 48 uint64_t m = 0; 49 int e, i; 50 51 for (i = 0; i < 8; i++) 52 m = (m<<8) + ext.mantissa[i]; 53 e = (((int)ext.exponent[0]&0x7f)<<8) | ext.exponent[1]; 54 if (e == 0x7fff && m) 55 return NAN; 56 e -= 16383 + 63; /* In IEEE 80 bits, the whole (i.e. 1.xxxx) 57 * mantissa bit is written as opposed to the 58 * single and double precision formats. */ 59 if (ext.exponent[0]&0x80) 60 m= -m; 61 return ldexp(m, e); 62} 63 64int64_t av_dbl2int(double d){ 65 int e; 66 if ( !d) return 0; 67 else if(d-d) return 0x7FF0000000000000LL + ((int64_t)(d<0)<<63) + (d!=d); 68 d= frexp(d, &e); 69 return (int64_t)(d<0)<<63 | (e+1022LL)<<52 | (int64_t)((fabs(d)-0.5)*(1LL<<53)); 70} 71 72int32_t av_flt2int(float d){ 73 int e; 74 if ( !d) return 0; 75 else if(d-d) return 0x7F800000 + ((d<0)<<31) + (d!=d); 76 d= frexp(d, &e); 77 return (d<0)<<31 | (e+126)<<23 | (int64_t)((fabs(d)-0.5)*(1<<24)); 78} 79 80AVExtFloat av_dbl2ext(double d){ 81 struct AVExtFloat ext= {{0}}; 82 int e, i; double f; uint64_t m; 83 84 f = fabs(frexp(d, &e)); 85 if (f >= 0.5 && f < 1) { 86 e += 16382; 87 ext.exponent[0] = e>>8; 88 ext.exponent[1] = e; 89 m = (uint64_t)ldexp(f, 64); 90 for (i=0; i < 8; i++) 91 ext.mantissa[i] = m>>(56-(i<<3)); 92 } else if (f != 0.0) { 93 ext.exponent[0] = 0x7f; ext.exponent[1] = 0xff; 94 if (!isinf(f)) 95 ext.mantissa[0] = ~0; 96 } 97 if (d < 0) 98 ext.exponent[0] |= 0x80; 99 return ext; 100} 101#endif /* FF_API_INTFLOAT */ 102