22 lines
955 B
JavaScript
22 lines
955 B
JavaScript
import * as encoding from '../encoding.js'
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import * as rabin from '../hash/rabin.js'
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import * as buffer from '../buffer.js'
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export const FingerprintTraitSymbol = Symbol('Fingerprint')
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/**
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* When implementing this trait, it is recommended to write some sort of "magic number" first to
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* ensure that different types of objects don't have the same fingerprint.
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*
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* The recommended pracice is to generate a random u32 number as your magic number. e.g. using
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* `console.log(random.uint32().toString(16))`
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*
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* @typedef {{ [FingerprintTraitSymbol]:()=>string } | import('../encoding.js').AnyEncodable} Fingerprintable
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*/
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/**
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* @param {Fingerprintable} a
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* @return {string}
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*/
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export const fingerprint = a => (a != null && /** @type {any} */ (a)[FingerprintTraitSymbol]?.()) || buffer.toBase64(rabin.fingerprint(rabin.StandardIrreducible128, encoding.encode(encoder => { encoding.writeUint32(encoder, 0x8de1c475); encoding.writeAny(encoder, a) })))
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