source: imaps-frontend/node_modules/es-abstract/helpers/bytesAsFloat32.js@ d565449

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Last change on this file since d565449 was d565449, checked in by stefan toskovski <stefantoska84@…>, 4 weeks ago

Update repo after prototype presentation

  • Property mode set to 100644
File size: 1.2 KB
Line 
1'use strict';
2
3var GetIntrinsic = require('get-intrinsic');
4
5var $pow = GetIntrinsic('%Math.pow%');
6
7module.exports = function bytesAsFloat32(rawBytes) {
8 // return new $Float32Array(new $Uint8Array(rawBytes).buffer)[0];
9
10 /*
11 Let value be the byte elements of rawBytes concatenated and interpreted as a little-endian bit string encoding of an IEEE 754-2008 binary32 value.
12If value is an IEEE 754-2008 binary32 NaN value, return the NaN Number value.
13Return the Number value that corresponds to value.
14 */
15 var sign = rawBytes[3] & 0x80 ? -1 : 1; // Check the sign bit
16 var exponent = ((rawBytes[3] & 0x7F) << 1)
17 | (rawBytes[2] >> 7); // Combine bits for exponent
18 var mantissa = ((rawBytes[2] & 0x7F) << 16)
19 | (rawBytes[1] << 8)
20 | rawBytes[0]; // Combine bits for mantissa
21
22 if (exponent === 0 && mantissa === 0) {
23 return sign === 1 ? 0 : -0;
24 }
25 if (exponent === 0xFF && mantissa === 0) {
26 return sign === 1 ? Infinity : -Infinity;
27 }
28 if (exponent === 0xFF && mantissa !== 0) {
29 return NaN;
30 }
31
32 exponent -= 127; // subtract the bias
33
34 if (exponent === -127) {
35 return sign * mantissa * $pow(2, -126 - 23);
36 }
37 return sign * (1 + (mantissa * $pow(2, -23))) * $pow(2, exponent);
38};
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