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- 'use strict';
- var $abs = require('math-intrinsics/abs');
- var $floor = require('math-intrinsics/floor');
- var $pow = require('math-intrinsics/pow');
- var isFinite = require('math-intrinsics/isFinite');
- var isNaN = require('math-intrinsics/isNaN');
- var isNegativeZero = require('math-intrinsics/isNegativeZero');
- var maxFiniteFloat32 = 3.4028234663852886e+38; // roughly 2 ** 128 - 1
- module.exports = function valueToFloat32Bytes(value, isLittleEndian) {
- if (isNaN(value)) {
- return isLittleEndian ? [0, 0, 192, 127] : [127, 192, 0, 0]; // hardcoded
- }
- var leastSig;
- if (value === 0) {
- leastSig = isNegativeZero(value) ? 0x80 : 0;
- return isLittleEndian ? [0, 0, 0, leastSig] : [leastSig, 0, 0, 0];
- }
- if ($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];
- };
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