34 lines
1.1 KiB
Plaintext
34 lines
1.1 KiB
Plaintext
/**
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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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*/ export const fnv1a52 = (str)=>{
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const len = str.length;
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let i = 0, t0 = 0, v0 = 0x2325, t1 = 0, v1 = 0x8422, t2 = 0, v2 = 0x9ce4, t3 = 0, 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 (v3 & 15) * 281474976710656 + v2 * 4294967296 + v1 * 65536 + (v0 ^ v3 >> 4);
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};
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export const generateETag = (payload, weak = false)=>{
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const prefix = weak ? 'W/"' : '"';
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return prefix + fnv1a52(payload).toString(36) + payload.length.toString(36) + '"';
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};
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//# sourceMappingURL=etag.js.map |