hexo/node_modules/es-abstract/2021/NumericToRawBytes.js

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2023-09-25 15:58:56 +08:00
'use strict';
var GetIntrinsic = require('get-intrinsic');
var $floor = GetIntrinsic('%Math.floor%');
var $log = GetIntrinsic('%Math.log%');
var $log2E = GetIntrinsic('%Math.LOG2E%');
var $log2 = GetIntrinsic('%Math.log2%', true) || function log2(x) {
return $log(x) * $log2E;
};
var $parseInt = GetIntrinsic('%parseInt%');
var $pow = GetIntrinsic('%Math.pow%');
var $Number = GetIntrinsic('%Number%');
var $TypeError = GetIntrinsic('%TypeError%');
var $BigInt = GetIntrinsic('%BigInt%', true);
var callBound = require('call-bind/callBound');
var $reverse = callBound('Array.prototype.reverse');
var $numberToString = callBound('Number.prototype.toString');
var $strSlice = callBound('String.prototype.slice');
var abs = require('./abs');
var hasOwnProperty = require('./HasOwnProperty');
var ToBigInt64 = require('./ToBigInt64');
var ToBigUint64 = require('./ToBigUint64');
var ToInt16 = require('./ToInt16');
var ToInt32 = require('./ToInt32');
var ToInt8 = require('./ToInt8');
var ToUint16 = require('./ToUint16');
var ToUint32 = require('./ToUint32');
var ToUint8 = require('./ToUint8');
var ToUint8Clamp = require('./ToUint8Clamp');
var Type = require('./Type');
var isNaN = require('../helpers/isNaN');
var isFinite = require('../helpers/isFinite');
var keys = require('object-keys');
// https://262.ecma-international.org/11.0/#table-the-typedarray-constructors
var TypeToSizes = {
__proto__: null,
Int8: 1,
Uint8: 1,
Uint8C: 1,
Int16: 2,
Uint16: 2,
Int32: 4,
Uint32: 4,
BigInt64: 8,
BigUint64: 8,
Float32: 4,
Float64: 8
};
var TypeToAO = {
__proto__: null,
Int8: ToInt8,
Uint8: ToUint8,
Uint8C: ToUint8Clamp,
Int16: ToInt16,
Uint16: ToUint16,
Int32: ToInt32,
Uint32: ToUint32,
BigInt64: ToBigInt64,
BigUint64: ToBigUint64
};
// https://262.ecma-international.org/11.0/#sec-numerictorawbytes
module.exports = function NumericToRawBytes(type, value, isLittleEndian) {
if (typeof type !== 'string' || !hasOwnProperty(TypeToSizes, type)) {
throw new $TypeError('Assertion failed: `type` must be a TypedArray element type: ' + keys(TypeToSizes));
}
if (Type(value) !== 'Number' && Type(value) !== 'BigInt') {
throw new $TypeError('Assertion failed: `value` must be a Number or a BigInt');
}
if (Type(isLittleEndian) !== 'Boolean') {
throw new $TypeError('Assertion failed: `isLittleEndian` must be a Boolean');
}
var rawBytes = [];
var exponent;
if (type === 'Float32') { // step 1
if (isNaN(value)) {
return isLittleEndian ? [0, 0, 192, 127] : [127, 192, 0, 0]; // hardcoded
}
var leastSig;
if (value === 0) {
leastSig = Object.is(value, -0) ? 0x80 : 0;
return isLittleEndian ? [0, 0, 0, leastSig] : [leastSig, 0, 0, 0];
}
if (!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
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);
mantissa = $floor(mantissa);
exponent += 127;
exponent = exponent << 23;
var result = sign << 31;
result |= exponent;
result |= mantissa;
var byte0 = result & 255;
result = result >> 8;
var byte1 = result & 255;
result = result >> 8;
var byte2 = result & 255;
result = result >> 8;
var byte3 = result & 255;
if (isLittleEndian) {
return [byte0, byte1, byte2, byte3];
}
return [byte3, byte2, byte1, byte0];
} else if (type === 'Float64') { // step 2
if (value === 0) {
leastSig = Object.is(value, -0) ? 0x80 : 0;
return isLittleEndian ? [0, 0, 0, 0, 0, 0, 0, leastSig] : [leastSig, 0, 0, 0, 0, 0, 0, 0];
}
if (isNaN(value)) {
return isLittleEndian ? [0, 0, 0, 0, 0, 0, 248, 127] : [127, 248, 0, 0, 0, 0, 0, 0];
}
if (!isFinite(value)) {
var infBytes = value < 0 ? [0, 0, 0, 0, 0, 0, 240, 255] : [0, 0, 0, 0, 0, 0, 240, 127];
return isLittleEndian ? infBytes : $reverse(infBytes);
}
var isNegative = value < 0;
if (isNegative) { value = -value; } // eslint-disable-line no-param-reassign
exponent = $floor($log2(value));
var significand = (value / $pow(2, exponent)) - 1;
var bitString = '';
for (var i = 0; i < 52; i++) {
significand *= 2;
if (significand >= 1) {
bitString += '1';
significand -= 1;
} else {
bitString += '0';
}
}
exponent += 1023;
var exponentBits = $numberToString(exponent, 2);
while (exponentBits.length < 11) { exponentBits = '0' + exponentBits; }
var fullBitString = (isNegative ? '1' : '0') + exponentBits + bitString;
while (fullBitString.length < 64) { fullBitString = '0' + fullBitString; }
for (i = 0; i < 8; i++) {
rawBytes[i] = $parseInt($strSlice(fullBitString, i * 8, (i + 1) * 8), 2);
}
return isLittleEndian ? $reverse(rawBytes) : rawBytes;
} // step 3
var n = TypeToSizes[type]; // step 3.a
var convOp = TypeToAO[type]; // step 3.b
var intValue = convOp(value); // step 3.c
var isBigInt = type === 'BigInt64' || type === 'BigUint64';
/*
if (intValue >= 0) { // step 3.d
// Let rawBytes be a List containing the n-byte binary encoding of intValue. If isLittleEndian is false, the bytes are ordered in big endian order. Otherwise, the bytes are ordered in little endian order.
} else { // step 3.e
// Let rawBytes be a List containing the n-byte binary 2's complement encoding of intValue. If isLittleEndian is false, the bytes are ordered in big endian order. Otherwise, the bytes are ordered in little endian order.
}
*/
if (intValue < 0) {
intValue = intValue >>> 0;
}
var OxFF = isBigInt ? $BigInt(0xFF) : 0xFF;
var eight = isBigInt ? $BigInt(8) : 8;
for (i = 0; i < n; i++) {
rawBytes[isLittleEndian ? i : n - 1 - i] = $Number(intValue & OxFF);
intValue = intValue >> eight;
}
return rawBytes; // step 4
};