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A pure-java CIFS/SMB client library
There is a newer version: 2.1.10
/* jcifs smb client library in Java
 * Copyright (C) 2000  "Michael B. Allen" 
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package jcifs.smb;


import java.util.Arrays;

import jcifs.BufferCache;
import jcifs.Configuration;


/**
 * Cache for reusable byte buffers
 * 
 * @internal
 */
public class BufferCacheImpl implements BufferCache {

    private final Object[] cache;
    private final int bufferSize;
    private int freeBuffers = 0;


    /**
     * 
     * @param cfg
     */
    public BufferCacheImpl ( Configuration cfg ) {
        this(cfg.getBufferCacheSize(), cfg.getMaximumBufferSize());
    }


    /**
     * @param maxBuffers
     * @param maxSize
     * 
     */
    public BufferCacheImpl ( int maxBuffers, int maxSize ) {
        this.cache = new Object[maxBuffers];
        this.bufferSize = maxSize;
    }


    /**
     * {@inheritDoc}
     *
     * @see jcifs.BufferCache#getBuffer()
     */
    @Override
    public byte[] getBuffer () {
        synchronized ( this.cache ) {
            byte[] buf;

            if ( this.freeBuffers > 0 ) {
                for ( int i = 0; i < this.cache.length; i++ ) {
                    if ( this.cache[ i ] != null ) {
                        buf = (byte[]) this.cache[ i ];
                        this.cache[ i ] = null;
                        this.freeBuffers--;
                        return buf;
                    }
                }
            }
            return new byte[this.bufferSize];
        }
    }


    /**
     * {@inheritDoc}
     *
     * @see jcifs.BufferCache#releaseBuffer(byte[])
     */
    @Override
    public void releaseBuffer ( byte[] buf ) {
        if ( buf == null ) {
            return;
        }
        // better safe than sorry: prevent leaks if there is some out of bound access
        Arrays.fill(buf, (byte) 0);
        synchronized ( this.cache ) {
            if ( this.freeBuffers < this.cache.length ) {
                for ( int i = 0; i < this.cache.length; i++ ) {
                    if ( this.cache[ i ] == null ) {
                        this.cache[ i ] = buf;
                        this.freeBuffers++;
                        return;
                    }
                }
            }
        }
    }
}