source: trip-planner-front/node_modules/@xtuc/ieee754/index.js@ 76712b2

Last change on this file since 76712b2 was 6a3a178, checked in by Ema <ema_spirova@…>, 3 years ago

initial commit

  • Property mode set to 100644
File size: 2.0 KB
Line 
1export function read(buffer, offset, isLE, mLen, nBytes) {
2 var e, m
3 var eLen = (nBytes * 8) - mLen - 1
4 var eMax = (1 << eLen) - 1
5 var eBias = eMax >> 1
6 var nBits = -7
7 var i = isLE ? (nBytes - 1) : 0
8 var d = isLE ? -1 : 1
9 var s = buffer[offset + i]
10
11 i += d
12
13 e = s & ((1 << (-nBits)) - 1)
14 s >>= (-nBits)
15 nBits += eLen
16 for (; nBits > 0; e = (e * 256) + buffer[offset + i], i += d, nBits -= 8) {}
17
18 m = e & ((1 << (-nBits)) - 1)
19 e >>= (-nBits)
20 nBits += mLen
21 for (; nBits > 0; m = (m * 256) + buffer[offset + i], i += d, nBits -= 8) {}
22
23 if (e === 0) {
24 e = 1 - eBias
25 } else if (e === eMax) {
26 return m ? NaN : ((s ? -1 : 1) * Infinity)
27 } else {
28 m = m + Math.pow(2, mLen)
29 e = e - eBias
30 }
31 return (s ? -1 : 1) * m * Math.pow(2, e - mLen)
32}
33
34export function write(buffer, value, offset, isLE, mLen, nBytes) {
35 var e, m, c
36 var eLen = (nBytes * 8) - mLen - 1
37 var eMax = (1 << eLen) - 1
38 var eBias = eMax >> 1
39 var rt = (mLen === 23 ? Math.pow(2, -24) - Math.pow(2, -77) : 0)
40 var i = isLE ? 0 : (nBytes - 1)
41 var d = isLE ? 1 : -1
42 var s = value < 0 || (value === 0 && 1 / value < 0) ? 1 : 0
43
44 value = Math.abs(value)
45
46 if (isNaN(value) || value === Infinity) {
47 m = isNaN(value) ? 1 : 0
48 e = eMax
49 } else {
50 e = Math.floor(Math.log(value) / Math.LN2)
51 if (value * (c = Math.pow(2, -e)) < 1) {
52 e--
53 c *= 2
54 }
55 if (e + eBias >= 1) {
56 value += rt / c
57 } else {
58 value += rt * Math.pow(2, 1 - eBias)
59 }
60 if (value * c >= 2) {
61 e++
62 c /= 2
63 }
64
65 if (e + eBias >= eMax) {
66 m = 0
67 e = eMax
68 } else if (e + eBias >= 1) {
69 m = ((value * c) - 1) * Math.pow(2, mLen)
70 e = e + eBias
71 } else {
72 m = value * Math.pow(2, eBias - 1) * Math.pow(2, mLen)
73 e = 0
74 }
75 }
76
77 for (; mLen >= 8; buffer[offset + i] = m & 0xff, i += d, m /= 256, mLen -= 8) {}
78
79 e = (e << mLen) | m
80 eLen += mLen
81 for (; eLen > 0; buffer[offset + i] = e & 0xff, i += d, e /= 256, eLen -= 8) {}
82
83 buffer[offset + i - d] |= s * 128
84}
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