// Copyright (C) 2016 Dmitry Chestnykh
// MIT License. See LICENSE file for details.

/**
 * Package hash provides interface for hash functions.
 */

/**
 * Hash interface describes properties of
 * cryptographic hash functions.
 */
export interface Hash {
    readonly digestLength: number;
    readonly blockSize: number;
    update(data: Uint8Array): this;
    reset(): this;
    finish(out: Uint8Array): this;
    digest(): Uint8Array;
    clean(): void;
}

export interface SerializableHash extends Hash {
    saveState(): any;
    restoreState(savedState: any): this;
    cleanSavedState(savedState: any): void;
}

export function isSerializableHash(h: Hash): h is SerializableHash {
    return (
        typeof (h as SerializableHash).saveState !== "undefined" &&
        typeof (h as SerializableHash).restoreState !== "undefined" &&
        typeof (h as SerializableHash).cleanSavedState !== "undefined"
    );
}

// TODO(dchest): figure out the standardized interface for XOF such as
// SHAKE and BLAKE2X.