UNPKG

1.18 kBJavaScriptView Raw
1export default function parse(input) {
2 input = input.toUpperCase();
3 var splitIndex = input.indexOf("P");
4 var mantissa, exponent;
5
6 if (splitIndex !== -1) {
7 mantissa = input.substring(0, splitIndex);
8 exponent = parseInt(input.substring(splitIndex + 1));
9 } else {
10 mantissa = input;
11 exponent = 0;
12 }
13
14 var dotIndex = mantissa.indexOf(".");
15
16 if (dotIndex !== -1) {
17 var integerPart = parseInt(mantissa.substring(0, dotIndex), 16);
18 var sign = Math.sign(integerPart);
19 integerPart = sign * integerPart;
20 var fractionLength = mantissa.length - dotIndex - 1;
21 var fractionalPart = parseInt(mantissa.substring(dotIndex + 1), 16);
22 var fraction = fractionLength > 0 ? fractionalPart / Math.pow(16, fractionLength) : 0;
23
24 if (sign === 0) {
25 if (fraction === 0) {
26 mantissa = sign;
27 } else {
28 if (Object.is(sign, -0)) {
29 mantissa = -fraction;
30 } else {
31 mantissa = fraction;
32 }
33 }
34 } else {
35 mantissa = sign * (integerPart + fraction);
36 }
37 } else {
38 mantissa = parseInt(mantissa, 16);
39 }
40
41 return mantissa * (splitIndex !== -1 ? Math.pow(2, exponent) : 1);
42}
\No newline at end of file