/*
* Copyright 2012 The Netty Project
*
* The Netty Project 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.jboss.netty.channel.socket.nio;
import org.jboss.netty.util.ExternalResourceReleasable;
import org.jboss.netty.util.internal.ByteBufferUtil;
import java.nio.ByteBuffer;
final class SocketReceiveBufferAllocator implements ExternalResourceReleasable {
private ByteBuffer buf;
private int exceedCount;
private final int maxExceedCount;
private final int percentual;
SocketReceiveBufferAllocator() {
this(16, 80);
}
SocketReceiveBufferAllocator(int maxExceedCount, int percentual) {
this.maxExceedCount = maxExceedCount;
this.percentual = percentual;
}
ByteBuffer get(int size) {
if (buf == null) {
return newBuffer(size);
}
if (buf.capacity() < size) {
return newBuffer(size);
}
if (buf.capacity() * percentual / 100 > size) {
if (++exceedCount == maxExceedCount) {
return newBuffer(size);
} else {
buf.clear();
}
} else {
exceedCount = 0;
buf.clear();
}
return buf;
}
private ByteBuffer newBuffer(int size) {
if (buf != null) {
exceedCount = 0;
ByteBufferUtil.destroy(buf);
}
buf = ByteBuffer.allocateDirect(normalizeCapacity(size));
return buf;
}
private static int normalizeCapacity(int capacity) {
// Normalize to multiple of 1024
int q = capacity >>> 10;
int r = capacity & 1023;
if (r != 0) {
q ++;
}
return q << 10;
}
public void releaseExternalResources() {
if (buf != null) {
ByteBufferUtil.destroy(buf);
}
}
}