Count existingCounter;
    int oldCount;
    if (count == 0) {
      existingCounter = backingMap.remove(element);
      oldCount = getAndSet(existingCounter, count);
    } else {
      existingCounter = backingMap.get(element);
      oldCount = getAndSet(existingCounter, count);

      if (existingCounter == null) {
        backingMap.put(element, new Count(count));
      }
    }

    value += delta;
  }

  public int addAndGet(int delta) {
    return value += delta;
  }

  public void set(int newValue) {
    value = newValue;
  }

  public int getAndSet(int newValue) {
    int result = value;
    value = newValue;
    return result;
  }

  @Override
  public int hashCode() {
    return value;
  }

  @Override

    value += delta;
  }

  public int addAndGet(int delta) {
    return value += delta;
  }

  public void set(int newValue) {
    value = newValue;
  }

  public int getAndSet(int newValue) {
    int result = value;
    value = newValue;
    return result;
  }

  @Override
  public int hashCode() {
    return value;
  }

  @Override

      }
      assertBitEquals(x, at.get());
      prev = x;
    }
  }

  /** getAndSet returns previous value and sets to given value */
  public void testGetAndSet() {
    double prev = Math.E;
    AtomicDouble at = new AtomicDouble(prev);
    for (double x : VALUES) {
      assertBitEquals(prev, at.getAndSet(x));
      prev = x;
    }
  }

  /** getAndAdd returns previous value and adds given value */

   *
   * @param newValue the new value
   * @return the previous value
   */
  public final double getAndSet(double newValue) {
    long next = doubleToRawLongBits(newValue);
    return longBitsToDouble(value.getAndSet(next));
  }

  /**
   * Atomically sets the value to the given updated value if the current value is <a

      }
      assertBitEquals(x, at.get());
      prev = x;
    }
  }

  /** getAndSet returns previous value and sets to given value */
  public void testGetAndSet() {
    double prev = Math.E;
    AtomicDouble at = new AtomicDouble(prev);
    for (double x : VALUES) {
      assertBitEquals(prev, at.getAndSet(x));
      prev = x;
    }
  }

  /** getAndAdd returns previous value and adds given value */

   *
   * @param i the index
   * @param newValue the new value
   * @return the previous value
   */
  public final double getAndSet(int i, double newValue) {
    long next = doubleToRawLongBits(newValue);
    return longBitsToDouble(longs.getAndSet(i, next));
  }

  /**
   * Atomically sets the element at position {@code i} to the given updated value if the current

        prev = x;
      }
    }
  }

  /** getAndSet returns previous value and sets to given value at given index */
  public void testGetAndSet() {
    AtomicDoubleArray aa = new AtomicDoubleArray(SIZE);
    for (int i : new int[] {0, SIZE - 1}) {
      double prev = 0.0;
      for (double x : VALUES) {
        assertBitEquals(prev, aa.getAndSet(i, x));
        prev = x;
      }
    }
  }

        prev = x;
      }
    }
  }

  /** getAndSet returns previous value and sets to given value at given index */
  public void testGetAndSet() {
    AtomicDoubleArray aa = new AtomicDoubleArray(SIZE);
    for (int i : new int[] {0, SIZE - 1}) {
      double prev = 0.0;
      for (double x : VALUES) {
        assertBitEquals(prev, aa.getAndSet(i, x));
        prev = x;
      }
    }
  }

    @Override
    @Nullable Listener gasListeners(AbstractFutureState<?> future, Listener update) {
      return listenersUpdater.getAndSet(future, update);
    }

    @Override
    @Nullable Waiter gasWaiters(AbstractFutureState<?> future, Waiter update) {
      return waitersUpdater.getAndSet(future, update);
    }

    @Override
    boolean casValue(AbstractFutureState<?> future, @Nullable Object expect, Object update) {