40 lines
1.4 KiB
JavaScript
40 lines
1.4 KiB
JavaScript
import { unsafeUniformArrayIntDistribution, unsafeUniformBigIntDistribution, unsafeUniformIntDistribution, } from 'pure-rand';
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export class Random {
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constructor(sourceRng) {
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this.internalRng = sourceRng.clone();
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}
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clone() {
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return new Random(this.internalRng);
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}
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next(bits) {
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return unsafeUniformIntDistribution(0, (1 << bits) - 1, this.internalRng);
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}
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nextBoolean() {
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return unsafeUniformIntDistribution(0, 1, this.internalRng) == 1;
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}
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nextInt(min, max) {
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return unsafeUniformIntDistribution(min == null ? Random.MIN_INT : min, max == null ? Random.MAX_INT : max, this.internalRng);
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}
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nextBigInt(min, max) {
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return unsafeUniformBigIntDistribution(min, max, this.internalRng);
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}
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nextArrayInt(min, max) {
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return unsafeUniformArrayIntDistribution(min, max, this.internalRng);
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}
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nextDouble() {
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const a = this.next(26);
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const b = this.next(27);
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return (a * Random.DBL_FACTOR + b) * Random.DBL_DIVISOR;
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}
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getState() {
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if ('getState' in this.internalRng && typeof this.internalRng.getState === 'function') {
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return this.internalRng.getState();
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}
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return undefined;
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}
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}
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Random.MIN_INT = 0x80000000 | 0;
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Random.MAX_INT = 0x7fffffff | 0;
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Random.DBL_FACTOR = Math.pow(2, 27);
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Random.DBL_DIVISOR = Math.pow(2, -53);
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