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.vector;
  
  import org.apache.arrow.vector.complex.RepeatedFixedWidthVectorLike;
  import org.apache.arrow.vector.complex.RepeatedVariableWidthVectorLike;
  
  /** Helper utility methods for allocating storage for Vectors. */
  public class AllocationHelper {
    private AllocationHelper() {}
  
    /**
     * Allocates the vector.
     *
     * @param v The vector to allocate.
     * @param valueCount Number of values to allocate.
     * @param bytesPerValue bytes per value.
     * @throws org.apache.arrow.memory.OutOfMemoryException if it can't allocate the memory.
     */
    public static void allocate(ValueVector v, int valueCount, int bytesPerValue) {
      allocate(v, valueCount, bytesPerValue, 5);
    }
  
    /**
     * Allocates memory for a vector assuming given number of values and their width.
     *
     * @param v The vector the allocate.
     * @param valueCount The number of elements to allocate.
     * @param bytesPerValue The bytes per value to use for allocating underlying storage
     * @param childValCount If <code>v</code> is a repeated vector, this is number of child elements
     *     to allocate.
     * @throws org.apache.arrow.memory.OutOfMemoryException if it can't allocate the memory.
     */
    public static void allocatePrecomputedChildCount(
        ValueVector v, int valueCount, int bytesPerValue, int childValCount) {
      if (v instanceof FixedWidthVector) {
        ((FixedWidthVector) v).allocateNew(valueCount);
      } else if (v instanceof VariableWidthVector) {
        ((VariableWidthVector) v).allocateNew(valueCount * bytesPerValue, valueCount);
      } else if (v instanceof RepeatedFixedWidthVectorLike) {
        ((RepeatedFixedWidthVectorLike) v).allocateNew(valueCount, childValCount);
      } else if (v instanceof RepeatedVariableWidthVectorLike) {
        ((RepeatedVariableWidthVectorLike) v)
            .allocateNew(childValCount * bytesPerValue, valueCount, childValCount);
      } else {
        v.allocateNew();
      }
    }
  
    /**
     * Allocates memory for a vector assuming given number of values and their width.
     *
     * @param v The vector the allocate.
     * @param valueCount The number of elements to allocate.
     * @param bytesPerValue The bytes per value to use for allocating underlying storage
     * @param repeatedPerTop If <code>v</code> is a repeated vector, this is assumed number of
     *     elements per child.
     * @throws org.apache.arrow.memory.OutOfMemoryException if it can't allocate the memory
     */
    public static void allocate(
        ValueVector v, int valueCount, int bytesPerValue, int repeatedPerTop) {
      allocatePrecomputedChildCount(v, valueCount, bytesPerValue, repeatedPerTop * valueCount);
    }
  
    /**
     * Allocates the exact amount if v is fixed width, otherwise falls back to dynamic allocation.
     *
     * @param v value vector we are trying to allocate
     * @param valueCount size we are trying to allocate
     * @throws org.apache.arrow.memory.OutOfMemoryException if it can't allocate the memory
     */
    public static void allocateNew(ValueVector v, int valueCount) {
      if (v instanceof FixedWidthVector) {
        ((FixedWidthVector) v).allocateNew(valueCount);
      } else if (v instanceof VariableWidthVector) {
        ((VariableWidthVector) v).allocateNew(valueCount);
      } else {
        v.allocateNew();
      }
    }
  }
  