content: /*
   * 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.arrow.algorithm.sort;
  
  import org.apache.arrow.memory.BufferAllocator;
  import org.apache.arrow.vector.IntVector;
  
  /** An off heap implementation of stack with int elements. */
  class OffHeapIntStack implements AutoCloseable {
  
    private static final int INIT_SIZE = 128;
  
    private IntVector intVector;
  
    private int top = 0;
  
    public OffHeapIntStack(BufferAllocator allocator) {
      intVector = new IntVector("int stack inner vector", allocator);
      intVector.allocateNew(INIT_SIZE);
      intVector.setValueCount(INIT_SIZE);
    }
  
    public void push(int value) {
      if (top == intVector.getValueCount()) {
        int targetCapacity = intVector.getValueCount() * 2;
        while (intVector.getValueCapacity() < targetCapacity) {
          intVector.reAlloc();
        }
        intVector.setValueCount(targetCapacity);
      }
  
      intVector.set(top++, value);
    }
  
    public int pop() {
      return intVector.get(--top);
    }
  
    public int getTop() {
      return intVector.get(top - 1);
    }
  
    public boolean isEmpty() {
      return top == 0;
    }
  
    public int getCount() {
      return top;
    }
  
    @Override
    public void close() {
      intVector.close();
    }
  }
  