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