1 files changed, 89 insertions, 0 deletions
diff --git a/std/hash/_fnv/fnv64.ts b/std/hash/_fnv/fnv64.ts
new file mode 100644
index 000000000..8a5b5187d
--- /dev/null
+++ b/std/hash/_fnv/fnv64.ts
@@ -0,0 +1,89 @@
+// 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 { mul64 } from "./util.ts";
+
+const offset64Lo = 2216829733;
+const offset64Hi = 3421674724;
+const prime64Lo = 435;
+const prime64Hi = 256;
+
+abstract class Fnv64Base<T> {
+  #stateHi: number;
+  #stateLo: number;
+
+  constructor() {
+    this.#stateHi = offset64Hi;
+    this.#stateLo = offset64Lo;
+  }
+
+  protected _updateState([newStateHi, newStateLo]: [number, number]): void {
+    this.#stateHi = newStateHi;
+    this.#stateLo = newStateLo;
+  }
+
+  reset(): void {
+    this.#stateHi = offset64Hi;
+    this.#stateLo = offset64Lo;
+  }
+
+  abstract write(data: Uint8Array): T;
+
+  size(): number {
+    return 8;
+  }
+
+  blockSize(): number {
+    return 1;
+  }
+
+  sum64(): [number, number] {
+    return [this.#stateHi, this.#stateLo];
+  }
+
+  sum(): Uint8Array {
+    return Uint8Array.from([
+      (this.#stateHi >> 24) & 0xff,
+      (this.#stateHi >> 16) & 0xff,
+      (this.#stateHi >> 8) & 0xff,
+      this.#stateHi & 0xff,
+      (this.#stateLo >> 24) & 0xff,
+      (this.#stateLo >> 16) & 0xff,
+      (this.#stateLo >> 8) & 0xff,
+      this.#stateLo & 0xff,
+    ]);
+  }
+}
+
+/** Fnv64 hash */
+export class Fnv64 extends Fnv64Base<Fnv64> {
+  write(data: Uint8Array): Fnv64 {
+    let [hashHi, hashLo] = this.sum64();
+
+    data.forEach((c) => {
+      [hashHi, hashLo] = mul64([hashHi, hashLo], [prime64Hi, prime64Lo]);
+      hashLo ^= c;
+    });
+
+    this._updateState([hashHi, hashLo]);
+    return this;
+  }
+}
+
+/** Fnv64a hash */
+export class Fnv64a extends Fnv64Base<Fnv64a> {
+  write(data: Uint8Array): Fnv64 {
+    let [hashHi, hashLo] = this.sum64();
+
+    data.forEach((c) => {
+      hashLo ^= c;
+      [hashHi, hashLo] = mul64([hashHi, hashLo], [prime64Hi, prime64Lo]);
+    });
+
+    this._updateState([hashHi, hashLo]);
+    return this;
+  }
+}