/*

  * 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.commons.collections.primitives;

 import java.io.IOException;

 import java.io.ObjectInputStream;

 import java.io.ObjectOutputStream;

 import java.io.Serializable;

 /**

  * A {@link ShortList} backed by an array of unsigned

  * <code>byte</code> values.

  * This list stores <code>short</code> values

  * in the range [{@link #MIN_VALUE},

  * {@link #MAX_VALUE}] in 8-bits 

  * per element.  Attempts to use elements outside this 

  * range may cause an 

  * {@link IllegalArgumentException IllegalArgumentException} 

  * to be thrown.

  * <p />

  * This implementation supports all optional methods.

  * 

  * @since Commons Primitives 1.0

  * @version $Revision: 480460 $ $Date: 2006-11-29 03:14:21 -0500 (Wed, 29 Nov 2006) $

  * 

  * @author Rodney Waldhoff 

  */

 public class ArrayUnsignedByteList extends RandomAccessShortList implements ShortList, Serializable {

     // constructors

     //-------------------------------------------------------------------------

     /** 

      * Construct an empty list with the default

      * initial capacity.

      */

     public ArrayUnsignedByteList() {

         this(8);

     }    

     /**

      * Construct an empty list with the given

      * initial capacity.

      * @throws IllegalArgumentException when <i>initialCapacity</i> is negative

      */

     public ArrayUnsignedByteList(int initialCapacity) {

         if(initialCapacity < 0) {

             throw new IllegalArgumentException("capacity " + initialCapacity);

         }

         _data = new byte[initialCapacity];

         _size = 0;

     }    

     /** 

      * Constructs a list containing the elements of the given collection, 

      * in the order they are returned by that collection's iterator.

      * 

      * @see ShortList#addAll(org.apache.commons.collections.primitives.ShortCollection)

      * @param that the non-<code>null</code> collection of <code>int</code>s 

      *        to add

      * @throws NullPointerException if <i>that</i> is <code>null</code>

      */

     public ArrayUnsignedByteList(ShortCollection that) { 

         this(that.size());

         addAll(that);

     }    

     /**

      * Constructs a list by copying the specified array.

      * 

      * @param array  the array to initialize the collection with

      * @throws NullPointerException if the array is <code>null</code>

      */

     public ArrayUnsignedByteList(short[] array) { 

         this(array.length);

         for(int i=0;i<array.length;i++) {

             _data[i] = fromShort(array[i]);

         }

         _size = array.length;

     }

     // ShortList methods

     //-------------------------------------------------------------------------

     /** 

      * Returns the element at the specified position within 

      * me. 

      * By construction, the returned value will be 

      * between {@link #MIN_VALUE} and {@link #MAX_VALUE}, inclusive.

      * 

      * @param index the index of the element to return

      * @return the value of the element at the specified position

      * @throws IndexOutOfBoundsException if the specified index is out of range

      */

     public short get(int index) {

         checkRange(index);

         return toShort(_data[index]);

     }

     public int size() {

         return _size;

     }

     /** 

      * Removes the element at the specified position in 

      * (optional operation).  Any subsequent elements 

      * are shifted to the left, subtracting one from their 

      * indices.  Returns the element that was removed.

      * By construction, the returned value will be 

      * between {@link #MIN_VALUE} and {@link #MAX_VALUE}, inclusive.

      * 

      * @param index the index of the element to remove

      * @return the value of the element that was removed

      * 

      * @throws UnsupportedOperationException when this operation is not 

      *         supported

      * @throws IndexOutOfBoundsException if the specified index is out of range

      */

     public short removeElementAt(int index) {

         checkRange(index);

         incrModCount();

         short oldval = toShort(_data[index]);

         int numtomove = _size - index - 1;

         if(numtomove > 0) {

             System.arraycopy(_data,index+1,_data,index,numtomove);

         }

         _size--;

         return oldval;

     }

     /** 

      * Replaces the element at the specified 

      * position in me with the specified element

      * (optional operation). 

      * Throws {@link IllegalArgumentException} if <i>element</i>

      * is less than {@link #MIN_VALUE} or greater than {@link #MAX_VALUE}.

      * 

      * @param index the index of the element to change

      * @param element the value to be stored at the specified position

      * @return the value previously stored at the specified position

      * 

      * @throws UnsupportedOperationException when this operation is not 

      *         supported

      * @throws IndexOutOfBoundsException if the specified index is out of range

      */

     public short set(int index, short element) {

         assertValidUnsignedByte(element);

         checkRange(index);

         incrModCount();

         short oldval = toShort(_data[index]);

         _data[index] = fromShort(element);

         return oldval;

     }

     /** 

      * Inserts the specified element at the specified position 

      * (optional operation). Shifts the element currently 

      * at that position (if any) and any subsequent elements to the 

      * right, increasing their indices.

      * Throws {@link IllegalArgumentException} if <i>element</i>

      * is less than {@link #MIN_VALUE} or greater than {@link #MAX_VALUE}.

      * 

      * @param index the index at which to insert the element

      * @param element the value to insert

      * 

      * @throws UnsupportedOperationException when this operation is not 

      *         supported

      * @throws IllegalArgumentException if some aspect of the specified element 

      *         prevents it from being added to me

      * @throws IndexOutOfBoundsException if the specified index is out of range

      */

     public void add(int index, short element) {

         assertValidUnsignedByte(element);

         checkRangeIncludingEndpoint(index);

         incrModCount();

         ensureCapacity(_size+1);

         int numtomove = _size-index;

         System.arraycopy(_data,index,_data,index+1,numtomove);

         _data[index] = fromShort(element);

         _size++;

     }

     public void clear() {

         incrModCount();

         _size = 0;

     }

     // capacity methods

     //-------------------------------------------------------------------------

     /** 

      * Increases my capacity, if necessary, to ensure that I can hold at 

      * least the number of elements specified by the minimum capacity 

      * argument without growing.

      */

     public void ensureCapacity(int mincap) {

         incrModCount();

         if(mincap > _data.length) {

             int newcap = (_data.length * 3)/2 + 1;

             byte[] olddata = _data;

             _data = new byte[newcap < mincap ? mincap : newcap];

             System.arraycopy(olddata,0,_data,0,_size);

         }

     }

     /** 

      * Reduce my capacity, if necessary, to match my

      * current {@link #size size}.

      */

     public void trimToSize() {

         incrModCount();

         if(_size < _data.length) {

             byte[] olddata = _data;

             _data = new byte[_size];

             System.arraycopy(olddata,0,_data,0,_size);

         }

     }

     // private methods

     //-------------------------------------------------------------------------

     private final short toShort(byte value) { 

         return (short)(value & MAX_VALUE);

     }

     private final byte fromShort(short value) {

         return (byte)(value&MAX_VALUE);

     }

     private final void assertValidUnsignedByte(short value) throws IllegalArgumentException {

         if(value > MAX_VALUE) {

             throw new IllegalArgumentException(value + " > " + MAX_VALUE);

         }

         if(value < MIN_VALUE) {

             throw new IllegalArgumentException(value + " < " + MIN_VALUE);

         }

     }

     private void writeObject(ObjectOutputStream out) throws IOException{

         out.defaultWriteObject();

         out.writeInt(_data.length);

         for(int i=0;i<_size;i++) {

             out.writeByte(_data[i]);

         }

     }

     private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {

         in.defaultReadObject();

         _data = new byte[in.readInt()];

         for(int i=0;i<_size;i++) {

             _data[i] = in.readByte();

         }

     }

     private final void checkRange(int index) {

         if(index < 0 || index >= _size) {

             throw new IndexOutOfBoundsException("Should be at least 0 and less than " + _size + ", found " + index);

         }

     }

     private final void checkRangeIncludingEndpoint(int index) {

         if(index < 0 || index > _size) {

             throw new IndexOutOfBoundsException("Should be at least 0 and at most " + _size + ", found " + index);

         }

     }

     private transient byte[] _data = null;

     private int _size = 0;

     /**

      *  The maximum possible unsigned 8-bit value.

      */

     public static final short MAX_VALUE = 0xFF;

     /**

      *  The minimum possible unsigned 8-bit value.

      */

     public static final short MIN_VALUE = 0;

 }