simplify
[libav.git] / libavutil / intfloat_readwrite.c
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1/*
2 * portable IEEE float/double read/write functions
3 *
4 * Copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>
5 *
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
10 *
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, write to the Free Software
5509bffa 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
c11c2bc2 19 */
115329f1 20
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21/**
22 * @file intfloat_readwrite.c
23 * Portable IEEE float/double read/write functions.
24 */
115329f1 25
c11c2bc2 26#include "common.h"
a851b8e8 27#include "intfloat_readwrite.h"
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28
29double av_int2dbl(int64_t v){
30 if(v+v > 0xFFELLU<<52)
31 return 0.0/0.0;
bf4e3bd2 32 return ldexp(((v&((1LL<<52)-1)) + (1LL<<52)) * (v>>63|1), (v>>52&0x7FF)-1075);
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33}
34
35float av_int2flt(int32_t v){
36 if(v+v > 0xFF000000U)
37 return 0.0/0.0;
38 return ldexp(((v&0x7FFFFF) + (1<<23)) * (v>>31|1), (v>>23&0xFF)-150);
39}
40
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41double av_ext2dbl(const AVExtFloat ext){
42 uint64_t m = 0;
43 int e, i;
44
45 for (i = 0; i < 8; i++)
767aeb11 46 m = (m<<8) + ext.mantissa[i];
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47 e = (((int)ext.exponent[0]&0x7f)<<8) | ext.exponent[1];
48 if (e == 0x7fff && m)
49 return 0.0/0.0;
50 e -= 16383 + 63; /* In IEEE 80 bits, the whole (i.e. 1.xxxx)
51 * mantissa bit is written as opposed to the
52 * single and double precision formats */
53 if (ext.exponent[0]&0x80)
767aeb11 54 m= -m;
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55 return ldexp(m, e);
56}
57
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58int64_t av_dbl2int(double d){
59 int e;
60 if ( !d) return 0;
61 else if(d-d) return 0x7FF0000000000000LL + ((int64_t)(d<0)<<63) + (d!=d);
62 d= frexp(d, &e);
63 return (int64_t)(d<0)<<63 | (e+1022LL)<<52 | (int64_t)((fabs(d)-0.5)*(1LL<<53));
64}
65
66int32_t av_flt2int(float d){
67 int e;
68 if ( !d) return 0;
69 else if(d-d) return 0x7F800000 + ((d<0)<<31) + (d!=d);
70 d= frexp(d, &e);
71 return (d<0)<<31 | (e+126)<<23 | (int64_t)((fabs(d)-0.5)*(1<<24));
72}
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73
74AVExtFloat av_dbl2ext(double d){
767aeb11 75 struct AVExtFloat ext= {{0}};
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76 int e, i; double f; uint64_t m;
77
78 f = fabs(frexp(d, &e));
79 if (f >= 0.5 && f < 1) {
80 e += 16382;
81 ext.exponent[0] = e>>8;
82 ext.exponent[1] = e;
83 m = (uint64_t)ldexp(f, 64);
84 for (i=0; i < 8; i++)
85 ext.mantissa[i] = m>>(56-(i<<3));
767aeb11 86 } else if (f != 0.0) {
f11288da 87 ext.exponent[0] = 0x7f; ext.exponent[1] = 0xff;
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88 if (f != 1/0.0)
89 ext.mantissa[0] = ~0;
90 }
91 if (d < 0)
92 ext.exponent[0] |= 0x80;
93 return ext;
94}
95