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47 lines
1.0 KiB
TypeScript
47 lines
1.0 KiB
TypeScript
/**
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* FNV-1a Hash implementation
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* @author Travis Webb (tjwebb) <me@traviswebb.com>
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*
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* Ported from https://github.com/tjwebb/fnv-plus/blob/master/index.js
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*
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* Simplified, optimized and add modified for 52 bit, which provides a larger hash space
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* and still making use of Javascript's 53-bit integer space.
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*/
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export function fnv1a52(str: string) {
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const len = str.length;
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let i = 0,
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t0 = 0,
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v0 = 0x2325,
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t1 = 0,
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v1 = 0x8422,
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t2 = 0,
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v2 = 0x9CE4,
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t3 = 0,
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v3 = 0xCBF2;
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while (i < len) {
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v0 ^= str.charCodeAt(i++);
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t0 = v0 * 435;
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t1 = v1 * 435;
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t2 = v2 * 435;
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t3 = v3 * 435;
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t2 += v0 << 8;
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t3 += v1 << 8;
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t1 += t0 >>> 16;
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v0 = t0 & 65535;
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t2 += t1 >>> 16;
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v1 = t1 & 65535;
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v3 = (t3 + (t2 >>> 16)) & 65535;
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v2 = t2 & 65535;
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}
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return (
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(v3 & 15) * 281_474_976_710_656
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+ v2 * 4_294_967_296
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+ v1 * 65536
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+ (v0 ^ (v3 >> 4))
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);
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}
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export const stringHash = (payload: string) => fnv1a52(payload).toString(36) + payload.length.toString(36);
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