/*
 * 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.lucene.analysis.compound.hyphenation;

import java.io.Serializable;

/**
 * This class implements a simple char vector with access to the underlying
 * array.
 * 
 * This class has been taken from the Apache FOP project (http://xmlgraphics.apache.org/fop/). They have been slightly modified. 
 */
public class CharVector implements Cloneable, Serializable {

  /**
   * Capacity increment size
   */
  private static final int DEFAULT_BLOCK_SIZE = 2048;

  private int blockSize;

  /**
   * The encapsulated array
   */
  private char[] array;

  /**
   * Points to next free item
   */
  private int n;

  public CharVector() {
    this(DEFAULT_BLOCK_SIZE);
  }

  public CharVector(int capacity) {
    if (capacity > 0) {
      blockSize = capacity;
    } else {
      blockSize = DEFAULT_BLOCK_SIZE;
    }
    array = new char[blockSize];
    n = 0;
  }

  public CharVector(char[] a) {
    blockSize = DEFAULT_BLOCK_SIZE;
    array = a;
    n = a.length;
  }

  public CharVector(char[] a, int capacity) {
    if (capacity > 0) {
      blockSize = capacity;
    } else {
      blockSize = DEFAULT_BLOCK_SIZE;
    }
    array = a;
    n = a.length;
  }

  /**
   * Reset Vector but don't resize or clear elements
   */
  public void clear() {
    n = 0;
  }

  @Override
  public Object clone() {
    CharVector cv = new CharVector(array.clone(), blockSize);
    cv.n = this.n;
    return cv;
  }

  public char[] getArray() {
    return array;
  }

  /**
   * return number of items in array
   */
  public int length() {
    return n;
  }

  /**
   * returns current capacity of array
   */
  public int capacity() {
    return array.length;
  }

  public void put(int index, char val) {
    array[index] = val;
  }

  public char get(int index) {
    return array[index];
  }

  public int alloc(int size) {
    int index = n;
    int len = array.length;
    if (n + size >= len) {
      char[] aux = new char[len + blockSize];
      System.arraycopy(array, 0, aux, 0, len);
      array = aux;
    }
    n += size;
    return index;
  }

  public void trimToSize() {
    if (n < array.length) {
      char[] aux = new char[n];
      System.arraycopy(array, 0, aux, 0, n);
      array = aux;
    }
  }

}