@eagleoutice/flowr-dev/util/hash.js

Static Dataflow Analyzer and Program Slicer for the R Programming Language

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.Hash53 = void 0;
/**
 * Portable, streaming, non-cryptographic 64-bit hash (cyrb53), emitted as 16 hex chars. Feed it in
 * chunks with {@link update} (so callers can hash data larger than a single string) and read the result
 * with {@link digest}. Used for content/update detection where a stable, fast digest is enough; browser-safe
 * (no node `crypto`, so it also works in the bundled/web build).
 *
 * cyrb53 is a public-domain hash by `bryc`.
 */
class Hash53 {
    h1 = 0xdeadbeef;
    h2 = 0x41c6ce57;
    update(str) {
        for (let i = 0; i < str.length; i++) {
            const ch = str.charCodeAt(i);
            this.h1 = Math.imul(this.h1 ^ ch, 2654435761);
            this.h2 = Math.imul(this.h2 ^ ch, 1597334677);
        }
        return this;
    }
    digest() {
        const h1 = Math.imul(this.h1 ^ (this.h1 >>> 16), 2246822507) ^ Math.imul(this.h2 ^ (this.h2 >>> 13), 3266489909);
        const h2 = Math.imul(this.h2 ^ (this.h2 >>> 16), 2246822507) ^ Math.imul(this.h1 ^ (this.h1 >>> 13), 3266489909);
        // `^` yields a *signed* int32, so coerce each half to unsigned (`>>> 0`) before hex, else a high bit prints a `-`
        return (h2 >>> 0).toString(16).padStart(8, '0') + (h1 >>> 0).toString(16).padStart(8, '0');
    }
}
exports.Hash53 = Hash53;
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