lucene/analysis/common/src/java/org/apache/lucene/analysis/compound/hyphenation/ByteVector.java

/*
 * 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;

/**
 * This class implements a simple byte 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 ByteVector {

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

  private int blockSize;

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

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

  public ByteVector() {
    this(DEFAULT_BLOCK_SIZE);
  }

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

  public ByteVector(byte[] a) {
    blockSize = DEFAULT_BLOCK_SIZE;
    array = a;
    n = 0;
  }

  public ByteVector(byte[] a, int capacity) {
    if (capacity > 0) {
      blockSize = capacity;
    } else {
      blockSize = DEFAULT_BLOCK_SIZE;
    }
    array = a;
    n = 0;
  }

  public byte[] 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, byte val) {
    array[index] = val;
  }

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

  /**
   * This is to implement memory allocation in the array. Like malloc().
   */
  public int alloc(int size) {
    int index = n;
    int len = array.length;
    if (n + size >= len) {
      byte[] aux = new byte[len + blockSize];
      System.arraycopy(array, 0, aux, 0, len);
      array = aux;
    }
    n += size;
    return index;
  }

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

}