14 lines
555 B
TypeScript
14 lines
555 B
TypeScript
// Deterministic non-cryptographic string hash (djb2 variant).
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// Used for stable pseudo-random selection keyed on date + user + bucket.
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export function stringHash(input: string): number {
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// 5381 is the canonical djb2 seed — a prime that empirically yields a good
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// distribution when combined with the `hash * 33 + c` step below.
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let hash = 5381
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for (let i = 0; i < input.length; i++) {
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// hash * 33 + char, kept in 32-bit range via `| 0`.
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hash = ((hash << 5) + hash + input.charCodeAt(i)) | 0
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}
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// Ensure non-negative.
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return hash >>> 0
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}
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