impl/ior/ByteBuffer.java

/*
 * Copyright (c) 2001, 2002, 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.corba.se.impl.ior ;


public class ByteBuffer {
    /**
     * The array buffer into which the components of the ByteBuffer are
     * stored. The capacity of the ByteBuffer is the length of this array buffer,
     * and is at least large enough to contain all the ByteBuffer's elements.<p>
     *
     * Any array elements following the last element in the ByteBuffer are 0.
     */
    protected byte elementData[];

    /**
     * The number of valid components in this {@code ByteBuffer} object.
     * Components {@code elementData[0]} through
     * {@code elementData[elementCount-1]} are the actual items.
     *
     * @serial
     */
    protected int elementCount;

    /**
     * The amount by which the capacity of the ByteBuffer is automatically
     * incremented when its size becomes greater than its capacity.  If
     * the capacity increment is less than or equal to zero, the capacity
     * of the ByteBuffer is doubled each time it needs to grow.
     *
     * @serial
     */
    protected int capacityIncrement;

    /**
     * Constructs an empty ByteBuffer with the specified initial capacity and
     * capacity increment.
     *
     * @param   initialCapacity     the initial capacity of the ByteBuffer.
     * @param   capacityIncrement   the amount by which the capacity is
     *                              increased when the ByteBuffer overflows.
     * @exception IllegalArgumentException if the specified initial capacity
     *               is negative
     */
    public ByteBuffer(int initialCapacity, int capacityIncrement) {
        super();
        if (initialCapacity < 0)
            throw new IllegalArgumentException("Illegal Capacity: "+
                                               initialCapacity);
        this.elementData = new byte[initialCapacity];
        this.capacityIncrement = capacityIncrement;
    }

    /**
     * Constructs an empty ByteBuffer with the specified initial capacity and
     * with its capacity increment equal to zero.
     *
     * @param   initialCapacity   the initial capacity of the ByteBuffer.
     * @exception IllegalArgumentException if the specified initial capacity
     *               is negative
     */
    public ByteBuffer(int initialCapacity) {
        this(initialCapacity, 0);
    }

    /**
     * Constructs an empty ByteBuffer so that its internal data array
     * has size {@code 10} and its standard capacity increment is
     * zero.
     */
    public ByteBuffer() {
        this(200);
    }

    /**
     * Trims the capacity of this ByteBuffer to be the ByteBuffer's current
     * size. If the capacity of this cector is larger than its current
     * size, then the capacity is changed to equal the size by replacing
     * its internal data array, kept in the field {@code elementData},
     * with a smaller one. An application can use this operation to
     * minimize the storage of a ByteBuffer.
     */
    public void trimToSize() {
        int oldCapacity = elementData.length;
        if (elementCount < oldCapacity) {
            byte oldData[] = elementData;
            elementData = new byte[elementCount];
            System.arraycopy(oldData, 0, elementData, 0, elementCount);
        }
    }

    /**
     * This implements the unsynchronized semantics of ensureCapacity.
     * Synchronized methods in this class can internally call this
     * method for ensuring capacity without incurring the cost of an
     * extra synchronization.
     *
     * @see java.util.ByteBuffer#ensureCapacity(int)
     */
    private void ensureCapacityHelper(int minCapacity) {
        int oldCapacity = elementData.length;
        if (minCapacity > oldCapacity) {
            byte oldData[] = elementData;
            int newCapacity = (capacityIncrement > 0) ?
                (oldCapacity + capacityIncrement) : (oldCapacity * 2);
            if (newCapacity < minCapacity) {
                newCapacity = minCapacity;
            }
            elementData = new byte[newCapacity];
            System.arraycopy(oldData, 0, elementData, 0, elementCount);
        }
    }

    /**
     * Returns the current capacity of this ByteBuffer.
     *
     * @return  the current capacity (the length of its internal
     *          data arary, kept in the field {@code elementData}
     *          of this ByteBuffer.
     */
    public int capacity() {
        return elementData.length;
    }

    /**
     * Returns the number of components in this ByteBuffer.
     *
     * @return  the number of components in this ByteBuffer.
     */
    public int size() {
        return elementCount;
    }

    /**
     * Tests if this ByteBuffer has no components.
     *
     * @return  {@code true} if and only if this ByteBuffer has
     *          no components, that is, its size is zero;
     *          {@code false} otherwise.
     */
    public boolean isEmpty() {
        return elementCount == 0;
    }

    public void append(byte value)
    {
        ensureCapacityHelper(elementCount + 1);
        elementData[elementCount++] = value;
    }

    public void append( int value )
    {
        ensureCapacityHelper(elementCount + 4);
        doAppend( value ) ;
    }

    private void doAppend( int value )
    {
        int current = value ;
        for (int ctr=0; ctr<4; ctr++) {
            elementData[elementCount+ctr] = (byte)(current & 255) ;
            current = current >> 8 ;
        }
        elementCount += 4 ;
    }

    public void append( String value )
    {
        byte[] data = value.getBytes() ;
        ensureCapacityHelper( elementCount + data.length + 4 ) ;
        doAppend( data.length ) ;
        System.arraycopy( data, 0, elementData, elementCount, data.length ) ;
        elementCount += data.length ;
    }

    /**
     * Returns an array containing all of the elements in this ByteBuffer
     * in the correct order.
     *
     * @since 1.2
     */
    public byte[] toArray() {
        return elementData ;
    }
}