org.apache.bookkeeper.util.ZeroBuffer Maven / Gradle / Ivy
/*
*
* 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();
}
}