repositories / deb_ffmpeg.git / blame
| Commit | Line | Data |
|---|---|---|
| 2ba45a60 DM |
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 | |
| 35 | double 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 | ||
| 41 | float 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 | ||
| 47 | double 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 | ||
| 64 | int64_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 | ||
| 72 | int32_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 | ||
| 80 | AVExtFloat 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 */ |