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author | Florian Dold <florian.dold@gmail.com> | 2017-08-14 05:01:11 +0200 |
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committer | Florian Dold <florian.dold@gmail.com> | 2017-08-14 05:02:09 +0200 |
commit | 363723fc84f7b8477592e0105aeb331ec9a017af (patch) | |
tree | 29f92724f34131bac64d6a318dd7e30612e631c7 /node_modules/es5-ext/math/_pack-ieee754.js | |
parent | 5634e77ad96bfe1818f6b6ee70b7379652e5487f (diff) |
node_modules
Diffstat (limited to 'node_modules/es5-ext/math/_pack-ieee754.js')
-rw-r--r-- | node_modules/es5-ext/math/_pack-ieee754.js | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/node_modules/es5-ext/math/_pack-ieee754.js b/node_modules/es5-ext/math/_pack-ieee754.js new file mode 100644 index 000000000..b77bc8d40 --- /dev/null +++ b/node_modules/es5-ext/math/_pack-ieee754.js @@ -0,0 +1,88 @@ +/* eslint no-bitwise: "off" */ +// Credit: https://github.com/paulmillr/es6-shim/ + +"use strict"; + +var abs = Math.abs + , floor = Math.floor + , log = Math.log + , min = Math.min + , pow = Math.pow + , LN2 = Math.LN2 + , roundToEven; + +roundToEven = function (num) { + var whole = floor(num), fraction = num - whole; + if (fraction < 0.5) return whole; + if (fraction > 0.5) return whole + 1; + return whole % 2 ? whole + 1 : whole; +}; + +// eslint-disable-next-line max-statements +module.exports = function (value, ebits, fbits) { + var bias = (1 << (ebits - 1)) - 1, sign, e, fraction, i, bits, str, bytes; + + // Compute sign, exponent, fraction + if (isNaN(value)) { + // NaN + // http://dev.w3.org/2006/webapi/WebIDL/#es-type-mapping + e = (1 << ebits) - 1; + fraction = pow(2, fbits - 1); + sign = 0; + } else if (value === Infinity || value === -Infinity) { + e = (1 << ebits) - 1; + fraction = 0; + sign = value < 0 ? 1 : 0; + } else if (value === 0) { + e = 0; + fraction = 0; + sign = 1 / value === -Infinity ? 1 : 0; + } else { + sign = value < 0; + value = abs(value); + + if (value >= pow(2, 1 - bias)) { + e = min(floor(log(value) / LN2), 1023); + fraction = roundToEven(value / pow(2, e) * pow(2, fbits)); + if (fraction / pow(2, fbits) >= 2) { + e += 1; + fraction = 1; + } + if (e > bias) { + // Overflow + e = (1 << ebits) - 1; + fraction = 0; + } else { + // Normal + e += bias; + fraction -= pow(2, fbits); + } + } else { + // Subnormal + e = 0; + fraction = roundToEven(value / pow(2, 1 - bias - fbits)); + } + } + + // Pack sign, exponent, fraction + bits = []; + for (i = fbits; i; i -= 1) { + bits.push(fraction % 2 ? 1 : 0); + fraction = floor(fraction / 2); + } + for (i = ebits; i; i -= 1) { + bits.push(e % 2 ? 1 : 0); + e = floor(e / 2); + } + bits.push(sign ? 1 : 0); + bits.reverse(); + str = bits.join(""); + + // Bits to bytes + bytes = []; + while (str.length) { + bytes.push(parseInt(str.substring(0, 8), 2)); + str = str.substring(8); + } + return bytes; +}; |