| /* eslint no-bitwise: "off" */ |
| // Credit: https://github.com/paulmillr/es6-shim/ |
| |
| "use strict"; |
| |
| var pow = Math.pow; |
| |
| module.exports = function (bytes, ebits, fbits) { |
| // Bytes to bits |
| var bits = [], i, j, bit, str, bias, sign, e, fraction; |
| |
| for (i = bytes.length; i; i -= 1) { |
| bit = bytes[i - 1]; |
| for (j = 8; j; j -= 1) { |
| bits.push(bit % 2 ? 1 : 0); |
| bit >>= 1; |
| } |
| } |
| bits.reverse(); |
| str = bits.join(""); |
| |
| // Unpack sign, exponent, fraction |
| bias = (1 << (ebits - 1)) - 1; |
| sign = parseInt(str.substring(0, 1), 2) ? -1 : 1; |
| e = parseInt(str.substring(1, 1 + ebits), 2); |
| fraction = parseInt(str.substring(1 + ebits), 2); |
| |
| // Produce number |
| if (e === (1 << ebits) - 1) return fraction === 0 ? sign * Infinity : NaN; |
| if (e > 0) return sign * pow(2, e - bias) * (1 + fraction / pow(2, fbits)); |
| if (fraction !== 0) return sign * pow(2, -(bias - 1)) * (fraction / pow(2, fbits)); |
| return sign < 0 ? -0 : 0; |
| }; |