51 lines
1.7 KiB
JavaScript
51 lines
1.7 KiB
JavaScript
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"use strict";
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exports.__esModule = true;
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exports.congruential32 = void 0;
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var MULTIPLIER = 0x000343fd;
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var INCREMENT = 0x00269ec3;
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var MASK = 0xffffffff;
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var MASK_2 = (1 << 31) - 1;
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var computeNextSeed = function (seed) {
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return (seed * MULTIPLIER + INCREMENT) & MASK;
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};
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var computeValueFromNextSeed = function (nextseed) {
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return (nextseed & MASK_2) >> 16;
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};
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var LinearCongruential32 = (function () {
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function LinearCongruential32(seed) {
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this.seed = seed;
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}
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LinearCongruential32.prototype.clone = function () {
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return new LinearCongruential32(this.seed);
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};
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LinearCongruential32.prototype.next = function () {
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var nextRng = new LinearCongruential32(this.seed);
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var out = nextRng.unsafeNext();
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return [out, nextRng];
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};
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LinearCongruential32.prototype.unsafeNext = function () {
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var s1 = computeNextSeed(this.seed);
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var v1 = computeValueFromNextSeed(s1);
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var s2 = computeNextSeed(s1);
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var v2 = computeValueFromNextSeed(s2);
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this.seed = computeNextSeed(s2);
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var v3 = computeValueFromNextSeed(this.seed);
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var vnext = v3 + ((v2 + (v1 << 15)) << 15);
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return vnext | 0;
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};
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LinearCongruential32.prototype.getState = function () {
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return [this.seed];
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};
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return LinearCongruential32;
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}());
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function fromState(state) {
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var valid = state.length === 1;
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if (!valid) {
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throw new Error('The state must have been produced by a congruential32 RandomGenerator');
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}
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return new LinearCongruential32(state[0]);
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}
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exports.congruential32 = Object.assign(function (seed) {
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return new LinearCongruential32(seed);
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}, { fromState: fromState });
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