/*
* Copyright (c) 2008-2017, Hazelcast, Inc. All Rights Reserved.
*
* Licensed 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 com.hazelcast.internal.util.hashslot.impl;
import com.hazelcast.internal.memory.MemoryManager;
import com.hazelcast.internal.util.hashslot.HashSlotArray8byteKey;
import com.hazelcast.internal.util.hashslot.HashSlotCursor8byteKey;
import static com.hazelcast.internal.util.hashslot.impl.CapacityUtil.DEFAULT_CAPACITY;
import static com.hazelcast.internal.util.hashslot.impl.CapacityUtil.DEFAULT_LOAD_FACTOR;
import static com.hazelcast.util.HashUtil.fastLongMix;
import static com.hazelcast.util.QuickMath.modPowerOfTwo;
/**
* Implementation of {@link HashSlotArray8byteKey} as a restriction of {@link HashSlotArrayBase}
* to a case where just {@code key1} is used.
* <p>
* This class uses the first 8 bytes of the value block for the unassigned sentinel.
* <strong>It is the responsibility of the caller to ensure that the unassigned sentinel
* is overwritten with a non-sentinel value as soon as a new slot is assigned (after calling
* {@link #ensure(long)} and getting a positive return value).</strong>
* For the same reason this class must not be instantiated with zero value length. Use
* {@link HashSlotArray8byteKeyNoValue} as a zero-length key implementation.
*/
public class HashSlotArray8byteKeyImpl extends HashSlotArrayBase implements HashSlotArray8byteKey {
private static final int KEY_SIZE = 8;
public HashSlotArray8byteKeyImpl(long unassignedSentinel, MemoryManager mm, int valueLength,
int initialCapacity, float loadFactor) {
this(unassignedSentinel, KEY_SIZE, mm, valueLength, initialCapacity, loadFactor);
assert valueLength > 0 : "Attempted to instantiate HashSlotArrayImpl with zero value length";
}
public HashSlotArray8byteKeyImpl(long unassignedSentinel, MemoryManager mm, int valueLength) {
this(unassignedSentinel, mm, valueLength, DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR);
assert valueLength > 0 : "Attempted to instantiate HashSlotArrayImpl with zero value length";
}
protected HashSlotArray8byteKeyImpl(long unassignedSentinel, long offsetOfUnassignedSentinel,
MemoryManager mm, int valueLength, int initialCapacity, float loadFactor
) {
super(unassignedSentinel, offsetOfUnassignedSentinel, mm, null, KEY_SIZE, valueLength,
initialCapacity, loadFactor);
assert modPowerOfTwo(valueLength, VALUE_SIZE_GRANULARITY) == 0
: "Value size must be a positive multiple of 8, but was " + valueLength;
}
/**
* {@inheritDoc}
*
* Whenever this method returns a positive value, the caller must ensure that the null-sentinel value
* at the returned address is overwritten with a non-sentinel value.
*/
@Override public long ensure(long key) {
return super.ensure0(key, 0);
}
@Override public long get(long key) {
return super.get0(key, 0);
}
@Override public boolean remove(long key) {
return super.remove0(key, 0);
}
@Override public HashSlotCursor8byteKey cursor() {
return new Cursor();
}
@Override protected long key2OfSlot(long baseAddress, long slot) {
return 0;
}
@Override protected void putKey(long baseAddress, long slot, long key, long ignored) {
mem().putLong(slotBase(baseAddress, slot) + KEY_1_OFFSET, key);
}
@Override protected long keyHash(long key, long ignored) {
return fastLongMix(key);
}
}