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/*
 * Copyright 2015-16, Yahoo! Inc.
 * Licensed under the terms of the Apache License 2.0. See LICENSE file at the project root for terms.
 */

package com.yahoo.sketches.tuple;

import com.yahoo.memory.Memory;

/**
 * Direct Union operation for tuple sketches of type ArrayOfDoubles.
 * This implementation uses data in a given Memory that is owned and managed by the caller.
 * This Memory can be off-heap, which if managed properly will greatly reduce the need for
 * the JVM to perform garbage collection.
 */
final class DirectArrayOfDoublesUnion extends ArrayOfDoublesUnion {

  private final Memory mem_;

  /**
   * Creates an instance of DirectArrayOfDoublesUnion
   * @param nomEntries Nominal number of entries. Forced to the nearest power of 2 greater than 
   * given value.
   * @param numValues Number of double values to keep for each key.
   * @param seed See seed
   * @param dstMem See Memory
   */
  DirectArrayOfDoublesUnion(final int nomEntries, final int numValues, final long seed, 
      final Memory dstMem) {
    super(new DirectArrayOfDoublesQuickSelectSketch(nomEntries, 3, 1f, numValues, seed, dstMem));
    mem_ = dstMem;
  }

  /**
   * Wraps the given Memory.
   * @param mem See Memory
   * @param seed See seed
   */
  DirectArrayOfDoublesUnion(final Memory mem, final long seed) {
    super(new DirectArrayOfDoublesQuickSelectSketch(mem, seed));
    mem_ = mem;
  }

  @Override
  public void reset() {
    sketch_ = new DirectArrayOfDoublesQuickSelectSketch(nomEntries_, 3, 1f, numValues_, seed_, mem_);
    theta_ = sketch_.getThetaLong();
  }

}