} else {
            final Object oldValue = dataMap.get(key);
            final Object[] oldValues;
            if (oldValue instanceof Object[]) {
                oldValues = (Object[]) oldValue;
            } else if (oldValue instanceof Collection<?>) {
                oldValues = ((Collection<?>) oldValue).toArray();
            } else {
                oldValues = new Object[] { oldValue };
            }

    Long result =
        map.compute(
            key,
            (k, oldValue) -> {
              if (oldValue == null || oldValue == 0) {
                noValue.set(true);
                return newValue;
              } else {
                return oldValue;
              }
            });
    return noValue.get() ? 0L : requireNonNull(result).longValue();
  }

    segment.setWeakValueReferenceForTesting(entry, oldValueRef);

    // no entry
    assertFalse(segment.replace(key, hash, oldValue, newValue));
    assertEquals(0, segment.count);

    // same value
    segment.setTableEntryForTesting(index, entry);
    segment.count++;
    assertEquals(1, segment.count);
    assertSame(oldValue, segment.get(key, hash));

    segment.setWeakValueReferenceForTesting(entry, oldValueRef);

    // no entry
    assertFalse(segment.replace(key, hash, oldValue, newValue));
    assertEquals(0, segment.count);

    // same value
    segment.setTableEntryForTesting(index, entry);
    segment.count++;
    assertEquals(1, segment.count);
    assertSame(oldValue, segment.get(key, hash));

    Set<Entry<K, V>> entrySet = map.entrySet();
    Entry<K, V> entry = entrySet.iterator().next();
    V oldValue = entry.getValue();
    V returnedValue = entry.setValue(oldValue);
    assertEquals(oldValue, returnedValue);
    assertTrue(entrySet.contains(mapEntry(entry.getKey(), oldValue)));
    assertEquals(oldValue, map.get(entry.getKey()));
    assertInvariants(map);
  }

  public void testEqualsForEqualMap() {

      long mask = 1L << bitIndex; // only cares about low 6 bits of bitIndex

      long oldValue;
      long newValue;
      do {
        oldValue = data.get(longIndex);
        newValue = oldValue | mask;
        if (oldValue == newValue) {
          return false;
        }
      } while (!data.compareAndSet(longIndex, oldValue, newValue));

      // We turned the bit on, so increment bitCount.

   */
  @CanIgnoreReturnValue
  public final double getAndAccumulate(int i, double x, DoubleBinaryOperator accumulatorFunction) {
    checkNotNull(accumulatorFunction);
    return getAndUpdate(i, oldValue -> accumulatorFunction.applyAsDouble(oldValue, x));
  }

  /**
   * Atomically updates the element at index {@code i} with the results of applying the given
   * function to the current and given values.
   *

  public V put(K key, V value) {
    checkNotNull(key);
    checkNotNull(value);
    Timestamped<V> oldValue = cachingHashMap.put(key, new Timestamped<V>(value, ticker));
    if (oldValue == null) {
      return null;
    }
    alertListenerIfPresent(key, oldValue.getValue(), RemovalCause.REPLACED);
    return oldValue.getValue();
  }

  @CanIgnoreReturnValue
  @Override
  public V remove(Object key) {

  public @Nullable V remove(@Nullable Object key) {
    Map<K, V> delegate = delegateOrNull();
    if (delegate != null) {
      return delegate.remove(key);
    }
    Object oldValue = removeHelper(key);
    return (oldValue == NOT_FOUND) ? null : (V) oldValue;
  }

  private @Nullable Object removeHelper(@Nullable Object key) {
    if (needsAllocArrays()) {
      return NOT_FOUND;
    }
    int mask = hashTableMask();

    int entryForKey = findEntryByKey(key, keyHash);
    if (entryForKey != ABSENT) {
      V oldValue = values[entryForKey];
      if (Objects.equals(oldValue, value)) {
        return value;
      } else {
        replaceValueInEntry(entryForKey, value, force);
        return oldValue;
      }
    }

    int valueHash = Hashing.smearedHash(value);