/*
 * 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.
 */
/*
 * $Id: ObjectVector.java 1225426 2011-12-29 04:13:08Z mrglavas $
 */
package org.apache.xml.utils;

A very simple table that stores a list of objects.
This version is based on a "realloc" strategy -- a simle array is
used, and when more storage is needed, a larger array is obtained
and all existing data is recopied into it. As a result, read/write
access to existing nodes is O(1) fast but appending may be O(N**2)
slow. 
@xsl.usage
internal/**
 * A very simple table that stores a list of objects.
 *
 * This version is based on a "realloc" strategy -- a simle array is
 * used, and when more storage is needed, a larger array is obtained
 * and all existing data is recopied into it. As a result, read/write
 * access to existing nodes is O(1) fast but appending may be O(N**2)
 * slow. 
 * @xsl.usage internal
 */
public class ObjectVector implements Cloneable
{

  
Size of blocks to allocate          /** Size of blocks to allocate          */
  protected int m_blocksize;

  
Array of objects          /** Array of objects          */
  protected Object m_map[]; 

  
Number of ints in array          /** Number of ints in array          */
  protected int m_firstFree = 0;

  
Size of array          /** Size of array          */
  protected int m_mapSize;

  
Default constructor.  Note that the default
block size is very small, for small lists.
/**
   * Default constructor.  Note that the default
   * block size is very small, for small lists.
   */
  public ObjectVector()
  {

    m_blocksize = 32;
    m_mapSize = m_blocksize;
    m_map = new Object[m_blocksize];
  }

  
Construct a IntVector, using the given block size.
Params:
blocksize – Size of block to allocate/**
   * Construct a IntVector, using the given block size.
   *
   * @param blocksize Size of block to allocate
   */
  public ObjectVector(int blocksize)
  {

    m_blocksize = blocksize;
    m_mapSize = blocksize;
    m_map = new Object[blocksize];
  }
  
  
Construct a IntVector, using the given block size.
Params:
blocksize – Size of block to allocate/**
   * Construct a IntVector, using the given block size.
   *
   * @param blocksize Size of block to allocate
   */
  public ObjectVector(int blocksize, int increaseSize)
  {

    m_blocksize = increaseSize;
    m_mapSize = blocksize;
    m_map = new Object[blocksize];
  }

  
Copy constructor for ObjectVector
Params:
v – Existing ObjectVector to copy/**
   * Copy constructor for ObjectVector
   * 
   * @param v Existing ObjectVector to copy
   */
  public ObjectVector(ObjectVector v)
  {
  	m_map = new Object[v.m_mapSize];
    m_mapSize = v.m_mapSize;
    m_firstFree = v.m_firstFree;
  	m_blocksize = v.m_blocksize;
  	System.arraycopy(v.m_map, 0, m_map, 0, m_firstFree);
  }

  
Get the length of the list.
Returns:
length of the list/**
   * Get the length of the list.
   *
   * @return length of the list
   */
  public final int size()
  {
    return m_firstFree;
  }
  
  
Get the length of the list.
Returns:
length of the list/**
   * Get the length of the list.
   *
   * @return length of the list
   */
  public final void setSize(int sz)
  {
    m_firstFree = sz;
  }


  
Append an object onto the vector.
Params:
value – Object to add to the list/**
   * Append an object onto the vector.
   *
   * @param value Object to add to the list 
   */
  public final void addElement(Object value)
  {

    if ((m_firstFree + 1) >= m_mapSize)
    {
      m_mapSize += m_blocksize;

      Object newMap[] = new Object[m_mapSize];

      System.arraycopy(m_map, 0, newMap, 0, m_firstFree + 1);

      m_map = newMap;
    }

    m_map[m_firstFree] = value;

    m_firstFree++;
  }
  
  
Append several Object values onto the vector.
Params:
value – Object to add to the list/**
   * Append several Object values onto the vector.
   *
   * @param value Object to add to the list 
   */
  public final void addElements(Object value, int numberOfElements)
  {

    if ((m_firstFree + numberOfElements) >= m_mapSize)
    {
      m_mapSize += (m_blocksize+numberOfElements);

      Object newMap[] = new Object[m_mapSize];

      System.arraycopy(m_map, 0, newMap, 0, m_firstFree + 1);

      m_map = newMap;
    }

    for (int i = 0; i < numberOfElements; i++) 
    {
      m_map[m_firstFree] = value;
      m_firstFree++;
    }
  }
  
  
Append several slots onto the vector, but do not set the values.
Params:
numberOfElements – number of slots to append/**
   * Append several slots onto the vector, but do not set the values.
   *
   * @param numberOfElements number of slots to append
   */
  public final void addElements(int numberOfElements)
  {

    if ((m_firstFree + numberOfElements) >= m_mapSize)
    {
      m_mapSize += (m_blocksize+numberOfElements);

      Object newMap[] = new Object[m_mapSize];

      System.arraycopy(m_map, 0, newMap, 0, m_firstFree + 1);

      m_map = newMap;
    }
    
    m_firstFree += numberOfElements;
  }
  

  
Inserts the specified object in this vector at the specified index.
Each component in this vector with an index greater or equal to
the specified index is shifted upward to have an index one greater
than the value it had previously.
Params:
value – Object to insert
at – Index of where to insert/**
   * Inserts the specified object in this vector at the specified index.
   * Each component in this vector with an index greater or equal to
   * the specified index is shifted upward to have an index one greater
   * than the value it had previously.
   *
   * @param value Object to insert
   * @param at Index of where to insert 
   */
  public final void insertElementAt(Object value, int at)
  {

    if ((m_firstFree + 1) >= m_mapSize)
    {
      m_mapSize += m_blocksize;

      Object newMap[] = new Object[m_mapSize];

      System.arraycopy(m_map, 0, newMap, 0, m_firstFree + 1);

      m_map = newMap;
    }

    if (at <= (m_firstFree - 1))
    {
      System.arraycopy(m_map, at, m_map, at + 1, m_firstFree - at);
    }

    m_map[at] = value;

    m_firstFree++;
  }

  
Remove all elements objects from the list. 
/**
   * Remove all elements objects from the list. 
   */
  public final void removeAllElements()
  {

    for (int i = 0; i < m_firstFree; i++)
    {
      m_map[i] = null;
    }

    m_firstFree = 0;
  }

  
Removes the first occurrence of the argument from this vector.
If the object is found in this vector, each component in the vector
with an index greater or equal to the object's index is shifted
downward to have an index one smaller than the value it had
previously.
Params:
s – Object to remove from array
Returns:
True if the object was removed, false if it was not found/**
   * Removes the first occurrence of the argument from this vector.
   * If the object is found in this vector, each component in the vector
   * with an index greater or equal to the object's index is shifted
   * downward to have an index one smaller than the value it had
   * previously.
   *
   * @param s Object to remove from array
   *
   * @return True if the object was removed, false if it was not found
   */
  public final boolean removeElement(Object s)
  {

    for (int i = 0; i < m_firstFree; i++)
    {
      if (m_map[i] == s)
      {
        if ((i + 1) < m_firstFree)
          System.arraycopy(m_map, i + 1, m_map, i - 1, m_firstFree - i);
        else
          m_map[i] = null;

        m_firstFree--;

        return true;
      }
    }

    return false;
  }

  
Deletes the component at the specified index. Each component in
this vector with an index greater or equal to the specified
index is shifted downward to have an index one smaller than
the value it had previously.
Params:
i – index of where to remove an object/**
   * Deletes the component at the specified index. Each component in
   * this vector with an index greater or equal to the specified
   * index is shifted downward to have an index one smaller than
   * the value it had previously.
   *
   * @param i index of where to remove an object
   */
  public final void removeElementAt(int i)
  {

    if (i > m_firstFree)
      System.arraycopy(m_map, i + 1, m_map, i, m_firstFree);
    else
      m_map[i] = null;

    m_firstFree--;
  }

  
Sets the component at the specified index of this vector to be the
specified object. The previous component at that position is discarded.
The index must be a value greater than or equal to 0 and less
than the current size of the vector.
Params:
value – object to set
index – Index of where to set the object/**
   * Sets the component at the specified index of this vector to be the
   * specified object. The previous component at that position is discarded.
   *
   * The index must be a value greater than or equal to 0 and less
   * than the current size of the vector.
   *
   * @param value object to set
   * @param index Index of where to set the object
   */
  public final void setElementAt(Object value, int index)
  {
    m_map[index] = value;
  }

  
Get the nth element.
Params:
i – index of object to get
Returns:
object at given index/**
   * Get the nth element.
   *
   * @param i index of object to get
   *
   * @return object at given index
   */
  public final Object elementAt(int i)
  {
    return m_map[i];
  }

  
Tell if the table contains the given Object.
Params:
s – object to look for
Returns:
true if the object is in the list/**
   * Tell if the table contains the given Object.
   *
   * @param s object to look for
   *
   * @return true if the object is in the list
   */
  public final boolean contains(Object s)
  {

    for (int i = 0; i < m_firstFree; i++)
    {
      if (m_map[i] == s)
        return true;
    }

    return false;
  }

  
Searches for the first occurence of the given argument,
beginning the search at index, and testing for equality
using the equals method.
Params:
elem – object to look for
index – Index of where to begin search
Returns:
the index of the first occurrence of the object
argument in this vector at position index or later in the
vector; returns -1 if the object is not found./**
   * Searches for the first occurence of the given argument,
   * beginning the search at index, and testing for equality
   * using the equals method.
   *
   * @param elem object to look for
   * @param index Index of where to begin search
   * @return the index of the first occurrence of the object
   * argument in this vector at position index or later in the
   * vector; returns -1 if the object is not found.
   */
  public final int indexOf(Object elem, int index)
  {

    for (int i = index; i < m_firstFree; i++)
    {
      if (m_map[i] == elem)
        return i;
    }

    return java.lang.Integer.MIN_VALUE;
  }

  
Searches for the first occurence of the given argument,
beginning the search at index, and testing for equality
using the equals method.
Params:
elem – object to look for
Returns:
the index of the first occurrence of the object
argument in this vector at position index or later in the
vector; returns -1 if the object is not found./**
   * Searches for the first occurence of the given argument,
   * beginning the search at index, and testing for equality
   * using the equals method.
   *
   * @param elem object to look for
   * @return the index of the first occurrence of the object
   * argument in this vector at position index or later in the
   * vector; returns -1 if the object is not found.
   */
  public final int indexOf(Object elem)
  {

    for (int i = 0; i < m_firstFree; i++)
    {
      if (m_map[i] == elem)
        return i;
    }

    return java.lang.Integer.MIN_VALUE;
  }

  
Searches for the first occurence of the given argument,
beginning the search at index, and testing for equality
using the equals method.
Params:
elem – Object to look for
Returns:
the index of the first occurrence of the object
argument in this vector at position index or later in the
vector; returns -1 if the object is not found./**
   * Searches for the first occurence of the given argument,
   * beginning the search at index, and testing for equality
   * using the equals method.
   *
   * @param elem Object to look for
   * @return the index of the first occurrence of the object
   * argument in this vector at position index or later in the
   * vector; returns -1 if the object is not found.
   */
  public final int lastIndexOf(Object elem)
  {

    for (int i = (m_firstFree - 1); i >= 0; i--)
    {
      if (m_map[i] == elem)
        return i;
    }

    return java.lang.Integer.MIN_VALUE;
  }
  
  /*
   * Reset the array to the supplied size.  
   * 
   * @param size 
   */
  public final void setToSize(int size) {
    
    Object newMap[] = new Object[size];
    
    System.arraycopy(m_map, 0, newMap, 0, m_firstFree);
    m_mapSize = size;

    m_map = newMap;
    
  }  
  
  
Returns clone of current ObjectVector
Returns:
clone of current ObjectVector/**
   * Returns clone of current ObjectVector
   * 
   * @return clone of current ObjectVector
   */
  public Object clone()
    throws CloneNotSupportedException
  {
  	return new ObjectVector(this);
  }
}