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// Ported from Go:
// https://github.com/golang/go/tree/go1.13.10/src/hash/fnv/fnv.go
// Copyright 2011 The Go Authors. All rights reserved. BSD license.
// https://github.com/golang/go/blob/master/LICENSE
// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
import { mul32 } from "./util.ts";
const offset32 = 2166136261;
const prime32 = 16777619;
abstract class Fnv32Base<T> {
#state: number;
constructor() {
this.#state = offset32;
}
protected _updateState(newState: number): void {
this.#state = newState;
}
reset(): void {
this.#state = offset32;
}
abstract write(data: Uint8Array): T;
size(): number {
return 4;
}
blockSize(): number {
return 1;
}
sum32(): number {
return this.#state;
}
sum(): Uint8Array {
return Uint8Array.from([
(this.#state >> 24) & 0xff,
(this.#state >> 16) & 0xff,
(this.#state >> 8) & 0xff,
this.#state & 0xff,
]);
}
}
/** Fnv32 hash */
export class Fnv32 extends Fnv32Base<Fnv32> {
write(data: Uint8Array): Fnv32 {
let hash = this.sum32();
data.forEach((c) => {
hash = mul32(hash, prime32);
hash ^= c;
});
this._updateState(hash);
return this;
}
}
/** Fnv32a hash */
export class Fnv32a extends Fnv32Base<Fnv32a> {
write(data: Uint8Array): Fnv32a {
let hash = this.sum32();
data.forEach((c) => {
hash ^= c;
hash = mul32(hash, prime32);
});
this._updateState(hash);
return this;
}
}
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