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	/*
	* Copyright (c) 2005, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package com.sun.xml.internal.stream.util;

	import java.lang.ref.*;

	/**
	* Buffer allocator for buffers of sizes 128 B, 2 KB and 8 KB. Includes
	* methods for allocating and freeing buffers.
	*
	* @author Binu John
	* @author Santiago PericasGeertsen
	*/
	public class BufferAllocator {
	private static final int SMALL_SIZE_LIMIT = 128;
	private static final int MEDIUM_SIZE_LIMIT = 2048;
	private static final int LARGE_SIZE_LIMIT = 8192;

	char[] smallCharBuffer;
	char[] mediumCharBuffer;
	char[] largeCharBuffer;

	byte[] smallByteBuffer;
	byte[] mediumByteBuffer;
	byte[] largeByteBuffer;

	public BufferAllocator() {
	}

	public char[] getCharBuffer(int size) {
	if (size <= SMALL_SIZE_LIMIT) {
	char[] buffer = smallCharBuffer;
	smallCharBuffer = null;
	return buffer;
	}
	else if (size <= MEDIUM_SIZE_LIMIT) {
	char[] buffer = mediumCharBuffer;
	mediumCharBuffer = null;
	return buffer;
	}
	else if (size <= LARGE_SIZE_LIMIT) {
	char[] buffer = largeCharBuffer;
	largeCharBuffer = null;
	return buffer;
	}
	return null;
	}

	public void returnCharBuffer(char[] c) {
	if (c == null) {
	return;
	}
	if (c.length <= SMALL_SIZE_LIMIT) {
	smallCharBuffer = c;
	}
	else if (c.length <= MEDIUM_SIZE_LIMIT) {
	mediumCharBuffer = c;
	}
	else if (c.length <= LARGE_SIZE_LIMIT) {
	largeCharBuffer = c;
	}
	}

	public byte[] getByteBuffer(int size) {
	if (size <= SMALL_SIZE_LIMIT) {
	byte[] buffer = smallByteBuffer;
	smallByteBuffer = null;
	return buffer;
	}
	else if (size <= MEDIUM_SIZE_LIMIT) {
	byte[] buffer = mediumByteBuffer;
	mediumByteBuffer = null;
	return buffer;
	}
	else if (size <= LARGE_SIZE_LIMIT) {
	byte[] buffer = largeByteBuffer;
	largeByteBuffer = null;
	return buffer;
	}
	return null;
	}

	public void returnByteBuffer(byte[] b) {
	if (b == null) {
	return;
	}
	if (b.length <= SMALL_SIZE_LIMIT) {
	smallByteBuffer = b;
	}
	else if (b.length <= MEDIUM_SIZE_LIMIT) {
	mediumByteBuffer = b;
	}
	else if (b.length <= LARGE_SIZE_LIMIT) {
	largeByteBuffer = b;
	}
	}

	}

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