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 Libav.
7 *
8 * Libav 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 * Libav 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 Libav; 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 "mathematics.h"
30#include "intfloat_readwrite.h"
31
32double av_int2dbl(int64_t v){
33    if((uint64_t)v+v > 0xFFEULL<<52)
34        return NAN;
35    return ldexp(((v&((1LL<<52)-1)) + (1LL<<52)) * (v>>63|1), (v>>52&0x7FF)-1075);
36}
37
38float av_int2flt(int32_t v){
39    if((uint32_t)v+v > 0xFF000000U)
40        return NAN;
41    return ldexp(((v&0x7FFFFF) + (1<<23)) * (v>>31|1), (v>>23&0xFF)-150);
42}
43
44double av_ext2dbl(const AVExtFloat ext){
45    uint64_t m = 0;
46    int e, i;
47
48    for (i = 0; i < 8; i++)
49        m = (m<<8) + ext.mantissa[i];
50    e = (((int)ext.exponent[0]&0x7f)<<8) | ext.exponent[1];
51    if (e == 0x7fff && m)
52        return NAN;
53    e -= 16383 + 63;        /* In IEEE 80 bits, the whole (i.e. 1.xxxx)
54                             * mantissa bit is written as opposed to the
55                             * single and double precision formats. */
56    if (ext.exponent[0]&0x80)
57        m= -m;
58    return ldexp(m, e);
59}
60
61int64_t av_dbl2int(double d){
62    int e;
63    if     ( !d) return 0;
64    else if(d-d) return 0x7FF0000000000000LL + ((int64_t)(d<0)<<63) + (d!=d);
65    d= frexp(d, &e);
66    return (int64_t)(d<0)<<63 | (e+1022LL)<<52 | (int64_t)((fabs(d)-0.5)*(1LL<<53));
67}
68
69int32_t av_flt2int(float d){
70    int e;
71    if     ( !d) return 0;
72    else if(d-d) return 0x7F800000 + ((d<0)<<31) + (d!=d);
73    d= frexp(d, &e);
74    return (d<0)<<31 | (e+126)<<23 | (int64_t)((fabs(d)-0.5)*(1<<24));
75}
76
77AVExtFloat av_dbl2ext(double d){
78    struct AVExtFloat ext= {{0}};
79    int e, i; double f; uint64_t m;
80
81    f = fabs(frexp(d, &e));
82    if (f >= 0.5 && f < 1) {
83        e += 16382;
84        ext.exponent[0] = e>>8;
85        ext.exponent[1] = e;
86        m = (uint64_t)ldexp(f, 64);
87        for (i=0; i < 8; i++)
88            ext.mantissa[i] = m>>(56-(i<<3));
89    } else if (f != 0.0) {
90        ext.exponent[0] = 0x7f; ext.exponent[1] = 0xff;
91        if (f != INFINITY)
92            ext.mantissa[0] = ~0;
93    }
94    if (d < 0)
95        ext.exponent[0] |= 0x80;
96    return ext;
97}
98
99