source: imaps-frontend/node_modules/core-js/internals/ieee754.js

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Last change on this file was 79a0317, checked in by stefan toskovski <stefantoska84@…>, 3 days ago

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1'use strict';
2// IEEE754 conversions based on https://github.com/feross/ieee754
3var $Array = Array;
4var abs = Math.abs;
5var pow = Math.pow;
6var floor = Math.floor;
7var log = Math.log;
8var LN2 = Math.LN2;
9
10var pack = function (number, mantissaLength, bytes) {
11 var buffer = $Array(bytes);
12 var exponentLength = bytes * 8 - mantissaLength - 1;
13 var eMax = (1 << exponentLength) - 1;
14 var eBias = eMax >> 1;
15 var rt = mantissaLength === 23 ? pow(2, -24) - pow(2, -77) : 0;
16 var sign = number < 0 || number === 0 && 1 / number < 0 ? 1 : 0;
17 var index = 0;
18 var exponent, mantissa, c;
19 number = abs(number);
20 // eslint-disable-next-line no-self-compare -- NaN check
21 if (number !== number || number === Infinity) {
22 // eslint-disable-next-line no-self-compare -- NaN check
23 mantissa = number !== number ? 1 : 0;
24 exponent = eMax;
25 } else {
26 exponent = floor(log(number) / LN2);
27 c = pow(2, -exponent);
28 if (number * c < 1) {
29 exponent--;
30 c *= 2;
31 }
32 if (exponent + eBias >= 1) {
33 number += rt / c;
34 } else {
35 number += rt * pow(2, 1 - eBias);
36 }
37 if (number * c >= 2) {
38 exponent++;
39 c /= 2;
40 }
41 if (exponent + eBias >= eMax) {
42 mantissa = 0;
43 exponent = eMax;
44 } else if (exponent + eBias >= 1) {
45 mantissa = (number * c - 1) * pow(2, mantissaLength);
46 exponent += eBias;
47 } else {
48 mantissa = number * pow(2, eBias - 1) * pow(2, mantissaLength);
49 exponent = 0;
50 }
51 }
52 while (mantissaLength >= 8) {
53 buffer[index++] = mantissa & 255;
54 mantissa /= 256;
55 mantissaLength -= 8;
56 }
57 exponent = exponent << mantissaLength | mantissa;
58 exponentLength += mantissaLength;
59 while (exponentLength > 0) {
60 buffer[index++] = exponent & 255;
61 exponent /= 256;
62 exponentLength -= 8;
63 }
64 buffer[index - 1] |= sign * 128;
65 return buffer;
66};
67
68var unpack = function (buffer, mantissaLength) {
69 var bytes = buffer.length;
70 var exponentLength = bytes * 8 - mantissaLength - 1;
71 var eMax = (1 << exponentLength) - 1;
72 var eBias = eMax >> 1;
73 var nBits = exponentLength - 7;
74 var index = bytes - 1;
75 var sign = buffer[index--];
76 var exponent = sign & 127;
77 var mantissa;
78 sign >>= 7;
79 while (nBits > 0) {
80 exponent = exponent * 256 + buffer[index--];
81 nBits -= 8;
82 }
83 mantissa = exponent & (1 << -nBits) - 1;
84 exponent >>= -nBits;
85 nBits += mantissaLength;
86 while (nBits > 0) {
87 mantissa = mantissa * 256 + buffer[index--];
88 nBits -= 8;
89 }
90 if (exponent === 0) {
91 exponent = 1 - eBias;
92 } else if (exponent === eMax) {
93 return mantissa ? NaN : sign ? -Infinity : Infinity;
94 } else {
95 mantissa += pow(2, mantissaLength);
96 exponent -= eBias;
97 } return (sign ? -1 : 1) * mantissa * pow(2, exponent - mantissaLength);
98};
99
100module.exports = {
101 pack: pack,
102 unpack: unpack
103};
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