lix-website/themes/lix/assets/bootstrap/node_modules/es-abstract/helpers/valueToFloat32Bytes.js
2024-04-26 22:49:34 -06:00

70 lines
1.6 KiB
JavaScript

'use strict';
var GetIntrinsic = require('get-intrinsic');
var $abs = GetIntrinsic('%Math.abs%');
var $floor = GetIntrinsic('%Math.floor%');
var $pow = GetIntrinsic('%Math.pow%');
var isFinite = require('./isFinite');
var isNaN = require('./isNaN');
var isNegativeZero = require('./isNegativeZero');
var maxFiniteFloat32 = 3.4028234663852886e+38; // roughly 2 ** 128 - 1
module.exports = function valueToFloat32Bytes(value, isLittleEndian) {
if (isNaN(value)) {
return isLittleEndian ? [0, 0, 192, 127] : [127, 192, 0, 0]; // hardcoded
}
var leastSig;
if (value === 0) {
leastSig = isNegativeZero(value) ? 0x80 : 0;
return isLittleEndian ? [0, 0, 0, leastSig] : [leastSig, 0, 0, 0];
}
if ($abs(value) > maxFiniteFloat32 || !isFinite(value)) {
leastSig = value < 0 ? 255 : 127;
return isLittleEndian ? [0, 0, 128, leastSig] : [leastSig, 128, 0, 0];
}
var sign = value < 0 ? 1 : 0;
value = $abs(value); // eslint-disable-line no-param-reassign
var exponent = 0;
while (value >= 2) {
exponent += 1;
value /= 2; // eslint-disable-line no-param-reassign
}
while (value < 1) {
exponent -= 1;
value *= 2; // eslint-disable-line no-param-reassign
}
var mantissa = value - 1;
mantissa *= $pow(2, 23) + 0.5;
mantissa = $floor(mantissa);
exponent += 127;
exponent <<= 23;
var result = (sign << 31)
| exponent
| mantissa;
var byte0 = result & 255;
result >>= 8;
var byte1 = result & 255;
result >>= 8;
var byte2 = result & 255;
result >>= 8;
var byte3 = result & 255;
if (isLittleEndian) {
return [byte0, byte1, byte2, byte3];
}
return [byte3, byte2, byte1, byte0];
};