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@Manouchehri
Forked from bartaz/gist:1119041
Created October 13, 2017 19:00
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Convert JavaScript number to string of 64bit double precision floating point representation (IEEE 754)
// Convert a JavaScript number to IEEE-754 Double Precision
// value represented as an array of 8 bytes (octets)
//
// http://cautionsingularityahead.blogspot.com/2010/04/javascript-and-ieee754-redux.html
function toIEEE754(v, ebits, fbits) {
var bias = (1 << (ebits - 1)) - 1;
// Compute sign, exponent, fraction
var s, e, f;
if (isNaN(v)) {
e = (1 << bias) - 1; f = 1; s = 0;
}
else if (v === Infinity || v === -Infinity) {
e = (1 << bias) - 1; f = 0; s = (v < 0) ? 1 : 0;
}
else if (v === 0) {
e = 0; f = 0; s = (1 / v === -Infinity) ? 1 : 0;
}
else {
s = v < 0;
v = Math.abs(v);
if (v >= Math.pow(2, 1 - bias)) {
var ln = Math.min(Math.floor(Math.log(v) / Math.LN2), bias);
e = ln + bias;
f = v * Math.pow(2, fbits - ln) - Math.pow(2, fbits);
}
else {
e = 0;
f = v / Math.pow(2, 1 - bias - fbits);
}
}
// Pack sign, exponent, fraction
var i, bits = [];
for (i = fbits; i; i -= 1) { bits.push(f % 2 ? 1 : 0); f = Math.floor(f / 2); }
for (i = ebits; i; i -= 1) { bits.push(e % 2 ? 1 : 0); e = Math.floor(e / 2); }
bits.push(s ? 1 : 0);
bits.reverse();
var str = bits.join('');
// Bits to bytes
var bytes = [];
while (str.length) {
bytes.push(parseInt(str.substring(0, 8), 2));
str = str.substring(8);
}
return bytes;
}
function fromIEEE754(bytes, ebits, fbits) {
// Bytes to bits
var bits = [];
for (var i = bytes.length; i; i -= 1) {
var byte = bytes[i - 1];
for (var j = 8; j; j -= 1) {
bits.push(byte % 2 ? 1 : 0); byte = byte >> 1;
}
}
bits.reverse();
var str = bits.join('');
// Unpack sign, exponent, fraction
var bias = (1 << (ebits - 1)) - 1;
var s = parseInt(str.substring(0, 1), 2) ? -1 : 1;
var e = parseInt(str.substring(1, 1 + ebits), 2);
var f = parseInt(str.substring(1 + ebits), 2);
// Produce number
if (e === (1 << ebits) - 1) {
return f !== 0 ? NaN : s * Infinity;
}
else if (e > 0) {
return s * Math.pow(2, e - bias) * (1 + f / Math.pow(2, fbits));
}
else if (f !== 0) {
return s * Math.pow(2, -(bias-1)) * (f / Math.pow(2, fbits));
}
else {
return s * 0;
}
}
function fromIEEE754Double(b) { return fromIEEE754(b, 11, 52); }
function toIEEE754Double(v) { return toIEEE754(v, 11, 52); }
function fromIEEE754Single(b) { return fromIEEE754(b, 8, 23); }
function toIEEE754Single(v) { return toIEEE754(v, 8, 23); }
// Convert array of octets to string binary representation
// by bartaz
function toIEEE754DoubleString(v) {
return toIEEE754Double(v)
.map(function(n){ for(n = n.toString(2);n.length < 8;n="0"+n); return n })
.join('')
.replace(/(.)(.{11})(.{52})/, "$1 $2 $3")
}
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