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184 lines
4.7 KiB
184 lines
4.7 KiB
5 years ago
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"use strict";
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var conversions = {};
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module.exports = conversions;
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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 evenRound(x) {
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// Round x to the nearest integer, choosing the even integer if it lies halfway between two.
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if ((x % 1) === 0.5 && (x & 1) === 0) { // [even number].5; round down (i.e. floor)
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return Math.floor(x);
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} else {
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return Math.round(x);
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}
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}
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function createNumberConversion(bitLength, typeOpts) {
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if (!typeOpts.unsigned) {
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--bitLength;
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}
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const lowerBound = typeOpts.unsigned ? 0 : -Math.pow(2, bitLength);
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const upperBound = Math.pow(2, bitLength) - 1;
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const moduloVal = typeOpts.moduloBitLength ? Math.pow(2, typeOpts.moduloBitLength) : Math.pow(2, bitLength);
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const moduloBound = typeOpts.moduloBitLength ? Math.pow(2, typeOpts.moduloBitLength - 1) : Math.pow(2, bitLength - 1);
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return function(V, opts) {
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if (!opts) opts = {};
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let x = +V;
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if (opts.enforceRange) {
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if (!Number.isFinite(x)) {
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throw new TypeError("Argument is not a finite number");
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}
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x = sign(x) * Math.floor(Math.abs(x));
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if (x < lowerBound || x > upperBound) {
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throw new TypeError("Argument is not in byte range");
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}
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return x;
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}
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if (!isNaN(x) && opts.clamp) {
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x = evenRound(x);
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if (x < lowerBound) x = lowerBound;
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if (x > upperBound) x = upperBound;
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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 = sign(x) * Math.floor(Math.abs(x));
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x = x % moduloVal;
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if (!typeOpts.unsigned && x >= moduloBound) {
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return x - moduloVal;
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}
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return x;
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}
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}
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conversions["void"] = function () {
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return undefined;
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};
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conversions["boolean"] = function (val) {
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return !!val;
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};
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conversions["byte"] = createNumberConversion(8, { unsigned: false });
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conversions["octet"] = createNumberConversion(8, { unsigned: true });
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conversions["short"] = createNumberConversion(16, { unsigned: false });
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conversions["unsigned short"] = createNumberConversion(16, { unsigned: true });
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conversions["long"] = createNumberConversion(32, { unsigned: false });
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conversions["unsigned long"] = createNumberConversion(32, { unsigned: true });
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conversions["long long"] = createNumberConversion(32, { unsigned: false, moduloBitLength: 64 });
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conversions["unsigned long long"] = createNumberConversion(32, { unsigned: true, moduloBitLength: 64 });
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conversions["double"] = function (V) {
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const x = +V;
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if (!Number.isFinite(x)) {
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throw new TypeError("Argument is not a finite floating-point value");
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}
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return x;
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};
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conversions["unrestricted double"] = function (V) {
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const x = +V;
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if (isNaN(x)) {
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throw new TypeError("Argument is NaN");
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}
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return x;
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};
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// not quite valid, but good enough for JS
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conversions["float"] = conversions["double"];
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conversions["unrestricted float"] = conversions["unrestricted double"];
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conversions["DOMString"] = function (V, opts) {
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if (!opts) opts = {};
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if (opts.treatNullAsEmptyString && V === null) {
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return "";
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}
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return String(V);
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};
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conversions["ByteString"] = function (V, opts) {
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const x = String(V);
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let c = undefined;
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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 new TypeError("Argument is not a valid bytestring");
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}
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}
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return x;
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};
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conversions["USVString"] = function (V) {
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const S = String(V);
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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 {
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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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}
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return U;
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};
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conversions["Date"] = function (V, opts) {
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if (!(V instanceof Date)) {
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throw new TypeError("Argument is not a Date object");
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}
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if (isNaN(V)) {
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return undefined;
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}
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return V;
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};
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conversions["RegExp"] = function (V, opts) {
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if (!(V instanceof RegExp)) {
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V = new RegExp(V);
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}
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return V;
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};
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