| /* |
| * Copyright (C) 2023, SAP SE and others |
| * |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Distribution License v. 1.0 which is available at |
| * https://www.eclipse.org/org/documents/edl-v10.php. |
| * |
| * SPDX-License-Identifier: BSD-3-Clause |
| */ |
| |
| package org.eclipse.jgit.internal.storage.io; |
| |
| import java.security.MessageDigest; |
| |
| import org.eclipse.jgit.lib.Constants; |
| |
| /** |
| * Dummy message digest consisting of only null bytes with the length of an |
| * ObjectId. This class can be used to skip computing a real digest. |
| */ |
| public final class NullMessageDigest extends MessageDigest { |
| private static final byte[] digest = new byte[Constants.OBJECT_ID_LENGTH]; |
| |
| private static final NullMessageDigest INSTANCE = new NullMessageDigest(); |
| |
| /** |
| * Get the only instance of NullMessageDigest |
| * |
| * @return the only instance of NullMessageDigest |
| */ |
| public static MessageDigest getInstance() { |
| return INSTANCE; |
| } |
| |
| private NullMessageDigest() { |
| super("null"); //$NON-NLS-1$ |
| } |
| |
| @Override |
| protected void engineUpdate(byte input) { |
| // empty |
| } |
| |
| @Override |
| protected void engineUpdate(byte[] input, int offset, int len) { |
| // empty |
| } |
| |
| @Override |
| protected byte[] engineDigest() { |
| return digest; |
| } |
| |
| @Override |
| protected void engineReset() { |
| // empty |
| } |
| } |