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489 lines
14 KiB
489 lines
14 KiB
"use strict"; |
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function makeException(ErrorType, message, opts = {}) { |
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if (opts.globals) { |
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ErrorType = opts.globals[ErrorType.name]; |
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} |
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return new ErrorType(`${opts.context ? opts.context : "Value"} ${message}.`); |
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} |
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function toNumber(value, opts = {}) { |
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if (!opts.globals) { |
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return +value; |
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} |
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if (typeof value === "bigint") { |
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throw opts.globals.TypeError("Cannot convert a BigInt value to a number"); |
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} |
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return opts.globals.Number(value); |
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} |
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function type(V) { |
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if (V === null) { |
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return "Null"; |
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} |
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switch (typeof V) { |
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case "undefined": |
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return "Undefined"; |
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case "boolean": |
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return "Boolean"; |
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case "number": |
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return "Number"; |
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case "string": |
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return "String"; |
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case "symbol": |
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return "Symbol"; |
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case "bigint": |
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return "BigInt"; |
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case "object": |
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// Falls through |
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case "function": |
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// Falls through |
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default: |
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// Per ES spec, typeof returns an implemention-defined value that is not any of the existing ones for |
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// uncallable non-standard exotic objects. Yet Type() which the Web IDL spec depends on returns Object for |
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// such cases. So treat the default case as an object. |
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return "Object"; |
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} |
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} |
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// Round x to the nearest integer, choosing the even integer if it lies halfway between two. |
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function evenRound(x) { |
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// There are four cases for numbers with fractional part being .5: |
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// |
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// case | x | floor(x) | round(x) | expected | x <> 0 | x % 1 | x & 1 | example |
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// 1 | 2n + 0.5 | 2n | 2n + 1 | 2n | > | 0.5 | 0 | 0.5 -> 0 |
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// 2 | 2n + 1.5 | 2n + 1 | 2n + 2 | 2n + 2 | > | 0.5 | 1 | 1.5 -> 2 |
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// 3 | -2n - 0.5 | -2n - 1 | -2n | -2n | < | -0.5 | 0 | -0.5 -> 0 |
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// 4 | -2n - 1.5 | -2n - 2 | -2n - 1 | -2n - 2 | < | -0.5 | 1 | -1.5 -> -2 |
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// (where n is a non-negative integer) |
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// |
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// Branch here for cases 1 and 4 |
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if ((x > 0 && (x % 1) === +0.5 && (x & 1) === 0) || |
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(x < 0 && (x % 1) === -0.5 && (x & 1) === 1)) { |
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return censorNegativeZero(Math.floor(x)); |
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} |
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return censorNegativeZero(Math.round(x)); |
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} |
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function integerPart(n) { |
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return censorNegativeZero(Math.trunc(n)); |
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} |
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function sign(x) { |
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return x < 0 ? -1 : 1; |
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} |
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function modulo(x, y) { |
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// https://tc39.github.io/ecma262/#eqn-modulo |
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// Note that http://stackoverflow.com/a/4467559/3191 does NOT work for large modulos |
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const signMightNotMatch = x % y; |
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if (sign(y) !== sign(signMightNotMatch)) { |
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return signMightNotMatch + y; |
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} |
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return signMightNotMatch; |
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} |
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function censorNegativeZero(x) { |
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return x === 0 ? 0 : x; |
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} |
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function createIntegerConversion(bitLength, typeOpts) { |
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const isSigned = !typeOpts.unsigned; |
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let lowerBound; |
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let upperBound; |
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if (bitLength === 64) { |
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upperBound = Number.MAX_SAFE_INTEGER; |
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lowerBound = !isSigned ? 0 : Number.MIN_SAFE_INTEGER; |
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} else if (!isSigned) { |
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lowerBound = 0; |
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upperBound = Math.pow(2, bitLength) - 1; |
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} else { |
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lowerBound = -Math.pow(2, bitLength - 1); |
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upperBound = Math.pow(2, bitLength - 1) - 1; |
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} |
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const twoToTheBitLength = Math.pow(2, bitLength); |
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const twoToOneLessThanTheBitLength = Math.pow(2, bitLength - 1); |
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return (V, opts = {}) => { |
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let x = toNumber(V, opts); |
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x = censorNegativeZero(x); |
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if (opts.enforceRange) { |
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if (!Number.isFinite(x)) { |
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throw makeException(TypeError, "is not a finite number", opts); |
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} |
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x = integerPart(x); |
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if (x < lowerBound || x > upperBound) { |
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throw makeException(TypeError, |
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`is outside the accepted range of ${lowerBound} to ${upperBound}, inclusive`, opts); |
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} |
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return x; |
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} |
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if (!Number.isNaN(x) && opts.clamp) { |
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x = Math.min(Math.max(x, lowerBound), upperBound); |
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x = evenRound(x); |
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return x; |
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} |
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if (!Number.isFinite(x) || x === 0) { |
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return 0; |
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} |
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x = integerPart(x); |
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// Math.pow(2, 64) is not accurately representable in JavaScript, so try to avoid these per-spec operations if |
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// possible. Hopefully it's an optimization for the non-64-bitLength cases too. |
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if (x >= lowerBound && x <= upperBound) { |
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return x; |
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} |
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// These will not work great for bitLength of 64, but oh well. See the README for more details. |
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x = modulo(x, twoToTheBitLength); |
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if (isSigned && x >= twoToOneLessThanTheBitLength) { |
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return x - twoToTheBitLength; |
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} |
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return x; |
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}; |
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} |
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function createLongLongConversion(bitLength, { unsigned }) { |
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const upperBound = Number.MAX_SAFE_INTEGER; |
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const lowerBound = unsigned ? 0 : Number.MIN_SAFE_INTEGER; |
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const asBigIntN = unsigned ? BigInt.asUintN : BigInt.asIntN; |
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return (V, opts = {}) => { |
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if (opts === undefined) { |
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opts = {}; |
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} |
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let x = toNumber(V, opts); |
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x = censorNegativeZero(x); |
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if (opts.enforceRange) { |
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if (!Number.isFinite(x)) { |
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throw makeException(TypeError, "is not a finite number", opts); |
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} |
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x = integerPart(x); |
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if (x < lowerBound || x > upperBound) { |
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throw makeException(TypeError, |
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`is outside the accepted range of ${lowerBound} to ${upperBound}, inclusive`, opts); |
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} |
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return x; |
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} |
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if (!Number.isNaN(x) && opts.clamp) { |
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x = Math.min(Math.max(x, lowerBound), upperBound); |
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x = evenRound(x); |
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return x; |
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} |
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if (!Number.isFinite(x) || x === 0) { |
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return 0; |
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} |
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let xBigInt = BigInt(integerPart(x)); |
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xBigInt = asBigIntN(bitLength, xBigInt); |
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return Number(xBigInt); |
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}; |
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} |
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exports.any = V => { |
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return V; |
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}; |
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exports.void = function () { |
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return undefined; |
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}; |
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exports.boolean = function (val) { |
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return !!val; |
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}; |
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exports.byte = createIntegerConversion(8, { unsigned: false }); |
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exports.octet = createIntegerConversion(8, { unsigned: true }); |
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exports.short = createIntegerConversion(16, { unsigned: false }); |
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exports["unsigned short"] = createIntegerConversion(16, { unsigned: true }); |
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exports.long = createIntegerConversion(32, { unsigned: false }); |
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exports["unsigned long"] = createIntegerConversion(32, { unsigned: true }); |
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exports["long long"] = createLongLongConversion(64, { unsigned: false }); |
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exports["unsigned long long"] = createLongLongConversion(64, { unsigned: true }); |
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exports.double = (V, opts) => { |
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const x = toNumber(V, opts); |
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if (!Number.isFinite(x)) { |
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throw makeException(TypeError, "is not a finite floating-point value", opts); |
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} |
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return x; |
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}; |
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exports["unrestricted double"] = (V, opts) => { |
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const x = toNumber(V, opts); |
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return x; |
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}; |
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exports.float = (V, opts) => { |
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const x = toNumber(V, opts); |
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if (!Number.isFinite(x)) { |
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throw makeException(TypeError, "is not a finite floating-point value", opts); |
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} |
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if (Object.is(x, -0)) { |
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return x; |
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} |
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const y = Math.fround(x); |
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if (!Number.isFinite(y)) { |
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throw makeException(TypeError, "is outside the range of a single-precision floating-point value", opts); |
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} |
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return y; |
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}; |
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exports["unrestricted float"] = (V, opts) => { |
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const x = toNumber(V, opts); |
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if (isNaN(x)) { |
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return x; |
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} |
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if (Object.is(x, -0)) { |
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return x; |
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} |
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return Math.fround(x); |
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}; |
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exports.DOMString = function (V, opts = {}) { |
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if (opts.treatNullAsEmptyString && V === null) { |
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return ""; |
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} |
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if (typeof V === "symbol") { |
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throw makeException(TypeError, "is a symbol, which cannot be converted to a string", opts); |
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} |
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const StringCtor = opts.globals ? opts.globals.String : String; |
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return StringCtor(V); |
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}; |
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exports.ByteString = (V, opts) => { |
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const x = exports.DOMString(V, opts); |
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let c; |
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for (let i = 0; (c = x.codePointAt(i)) !== undefined; ++i) { |
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if (c > 255) { |
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throw makeException(TypeError, "is not a valid ByteString", opts); |
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} |
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} |
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return x; |
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}; |
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exports.USVString = (V, opts) => { |
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const S = exports.DOMString(V, opts); |
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const n = S.length; |
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const U = []; |
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for (let i = 0; i < n; ++i) { |
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const c = S.charCodeAt(i); |
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if (c < 0xD800 || c > 0xDFFF) { |
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U.push(String.fromCodePoint(c)); |
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} else if (0xDC00 <= c && c <= 0xDFFF) { |
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U.push(String.fromCodePoint(0xFFFD)); |
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} else if (i === n - 1) { |
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U.push(String.fromCodePoint(0xFFFD)); |
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} else { |
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const d = S.charCodeAt(i + 1); |
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if (0xDC00 <= d && d <= 0xDFFF) { |
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const a = c & 0x3FF; |
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const b = d & 0x3FF; |
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U.push(String.fromCodePoint((2 << 15) + ((2 << 9) * a) + b)); |
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++i; |
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} else { |
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U.push(String.fromCodePoint(0xFFFD)); |
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} |
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} |
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} |
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return U.join(""); |
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}; |
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exports.object = (V, opts) => { |
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if (type(V) !== "Object") { |
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throw makeException(TypeError, "is not an object", opts); |
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} |
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return V; |
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}; |
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// Not exported, but used in Function and VoidFunction. |
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// Neither Function nor VoidFunction is defined with [TreatNonObjectAsNull], so |
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// handling for that is omitted. |
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function convertCallbackFunction(V, opts) { |
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if (typeof V !== "function") { |
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throw makeException(TypeError, "is not a function", opts); |
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} |
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return V; |
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} |
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const abByteLengthGetter = |
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Object.getOwnPropertyDescriptor(ArrayBuffer.prototype, "byteLength").get; |
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const sabByteLengthGetter = |
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Object.getOwnPropertyDescriptor(SharedArrayBuffer.prototype, "byteLength").get; |
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function isNonSharedArrayBuffer(V) { |
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try { |
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// This will throw on SharedArrayBuffers, but not detached ArrayBuffers. |
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// (The spec says it should throw, but the spec conflicts with implementations: https://github.com/tc39/ecma262/issues/678) |
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abByteLengthGetter.call(V); |
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return true; |
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} catch { |
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return false; |
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} |
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} |
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function isSharedArrayBuffer(V) { |
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try { |
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sabByteLengthGetter.call(V); |
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return true; |
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} catch { |
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return false; |
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} |
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} |
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function isArrayBufferDetached(V) { |
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try { |
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// eslint-disable-next-line no-new |
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new Uint8Array(V); |
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return false; |
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} catch { |
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return true; |
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} |
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} |
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exports.ArrayBuffer = (V, opts = {}) => { |
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if (!isNonSharedArrayBuffer(V)) { |
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if (opts.allowShared && !isSharedArrayBuffer(V)) { |
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throw makeException(TypeError, "is not an ArrayBuffer or SharedArrayBuffer", opts); |
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} |
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throw makeException(TypeError, "is not an ArrayBuffer", opts); |
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} |
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if (isArrayBufferDetached(V)) { |
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throw makeException(TypeError, "is a detached ArrayBuffer", opts); |
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} |
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return V; |
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}; |
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const dvByteLengthGetter = |
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Object.getOwnPropertyDescriptor(DataView.prototype, "byteLength").get; |
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exports.DataView = (V, opts = {}) => { |
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try { |
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dvByteLengthGetter.call(V); |
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} catch (e) { |
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throw makeException(TypeError, "is not a DataView", opts); |
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} |
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if (!opts.allowShared && isSharedArrayBuffer(V.buffer)) { |
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throw makeException(TypeError, "is backed by a SharedArrayBuffer, which is not allowed", opts); |
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} |
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if (isArrayBufferDetached(V.buffer)) { |
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throw makeException(TypeError, "is backed by a detached ArrayBuffer", opts); |
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} |
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return V; |
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}; |
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// Returns the unforgeable `TypedArray` constructor name or `undefined`, |
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// if the `this` value isn't a valid `TypedArray` object. |
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// |
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// https://tc39.es/ecma262/#sec-get-%typedarray%.prototype-@@tostringtag |
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const typedArrayNameGetter = Object.getOwnPropertyDescriptor( |
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Object.getPrototypeOf(Uint8Array).prototype, |
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Symbol.toStringTag |
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).get; |
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[ |
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Int8Array, Int16Array, Int32Array, Uint8Array, |
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Uint16Array, Uint32Array, Uint8ClampedArray, Float32Array, Float64Array |
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].forEach(func => { |
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const name = func.name; |
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const article = /^[AEIOU]/.test(name) ? "an" : "a"; |
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exports[name] = (V, opts = {}) => { |
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if (!ArrayBuffer.isView(V) || typedArrayNameGetter.call(V) !== name) { |
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throw makeException(TypeError, `is not ${article} ${name} object`, opts); |
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} |
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if (!opts.allowShared && isSharedArrayBuffer(V.buffer)) { |
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throw makeException(TypeError, "is a view on a SharedArrayBuffer, which is not allowed", opts); |
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} |
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if (isArrayBufferDetached(V.buffer)) { |
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throw makeException(TypeError, "is a view on a detached ArrayBuffer", opts); |
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} |
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return V; |
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}; |
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}); |
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// Common definitions |
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exports.ArrayBufferView = (V, opts = {}) => { |
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if (!ArrayBuffer.isView(V)) { |
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throw makeException(TypeError, "is not a view on an ArrayBuffer or SharedArrayBuffer", opts); |
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} |
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if (!opts.allowShared && isSharedArrayBuffer(V.buffer)) { |
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throw makeException(TypeError, "is a view on a SharedArrayBuffer, which is not allowed", opts); |
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} |
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if (isArrayBufferDetached(V.buffer)) { |
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throw makeException(TypeError, "is a view on a detached ArrayBuffer", opts); |
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} |
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return V; |
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}; |
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exports.BufferSource = (V, opts = {}) => { |
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if (ArrayBuffer.isView(V)) { |
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if (!opts.allowShared && isSharedArrayBuffer(V.buffer)) { |
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throw makeException(TypeError, "is a view on a SharedArrayBuffer, which is not allowed", opts); |
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} |
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if (isArrayBufferDetached(V.buffer)) { |
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throw makeException(TypeError, "is a view on a detached ArrayBuffer", opts); |
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} |
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return V; |
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} |
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if (!opts.allowShared && !isNonSharedArrayBuffer(V)) { |
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throw makeException(TypeError, "is not an ArrayBuffer or a view on one", opts); |
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} |
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if (opts.allowShared && !isSharedArrayBuffer(V) && !isNonSharedArrayBuffer(V)) { |
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throw makeException(TypeError, "is not an ArrayBuffer, SharedArrayBufer, or a view on one", opts); |
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} |
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if (isArrayBufferDetached(V)) { |
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throw makeException(TypeError, "is a detached ArrayBuffer", opts); |
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} |
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return V; |
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}; |
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exports.DOMTimeStamp = exports["unsigned long long"]; |
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exports.Function = convertCallbackFunction; |
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exports.VoidFunction = convertCallbackFunction;
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