| /** |
| * |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| * |
| */ |
| |
| package org.apache.bookkeeper.util; |
| |
| import java.nio.ByteBuffer; |
| |
| /** |
| * Zero buffer utility. |
| * |
| */ |
| |
| public class ZeroBuffer { |
| private static final byte[] zeroBytes = new byte[64 * 1024]; |
| |
| /** |
| * Fill zeros into given buffer. |
| * @param dst |
| */ |
| public static void put(ByteBuffer dst) { |
| put(dst, dst.remaining()); |
| } |
| |
| /** |
| * Fill zeros into given buffer up to given length. |
| * @param dst |
| * @param length |
| */ |
| public static void put(ByteBuffer dst, int length) { |
| while (length > zeroBytes.length) { |
| dst.put(zeroBytes); |
| length -= zeroBytes.length; |
| } |
| if (length > 0) { |
| dst.put(zeroBytes, 0, length); |
| } |
| } |
| |
| /** |
| * Returns read-only zero-filled buffer. |
| * @param length |
| * @return ByteBuffer |
| */ |
| public static ByteBuffer readOnlyBuffer(int length) { |
| ByteBuffer buffer; |
| if (length <= zeroBytes.length) { |
| buffer = ByteBuffer.wrap(zeroBytes, 0, length); |
| } else { |
| buffer = ByteBuffer.allocate(length); |
| put(buffer); |
| buffer.rewind(); |
| } |
| return buffer.asReadOnlyBuffer(); |
| } |
| } |