25 lines
844 B
JavaScript
25 lines
844 B
JavaScript
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var SBigInt = typeof BigInt !== 'undefined' ? BigInt : undefined;
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export function unsafeUniformBigIntDistribution(from, to, rng) {
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var diff = to - from + SBigInt(1);
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var MinRng = SBigInt(-0x80000000);
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var NumValues = SBigInt(0x100000000);
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var FinalNumValues = NumValues;
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var NumIterations = 1;
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while (FinalNumValues < diff) {
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FinalNumValues *= NumValues;
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++NumIterations;
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}
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var MaxAcceptedRandom = FinalNumValues - (FinalNumValues % diff);
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while (true) {
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var value = SBigInt(0);
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for (var num = 0; num !== NumIterations; ++num) {
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var out = rng.unsafeNext();
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value = NumValues * value + (SBigInt(out) - MinRng);
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}
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if (value < MaxAcceptedRandom) {
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var inDiff = value % diff;
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return inDiff + from;
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}
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}
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}
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