org.agrona.collections.Int2IntHashMap Maven / Gradle / Ivy
Show all versions of Agrona Show documentation
/*
* Copyright 2014 - 2016 Real Logic Ltd.
*
* 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 org.agrona.collections;
import org.agrona.BitUtil;
import org.agrona.generation.DoNotSub;
import java.util.*;
import java.util.function.BiConsumer;
import static org.agrona.collections.CollectionUtil.validateLoadFactor;
/**
* A open addressing with linear probing hash map specialised for primitive key and value pairs.
*/
public class Int2IntHashMap implements Map
{
@DoNotSub private final float loadFactor;
private final int missingValue;
@DoNotSub private int resizeThreshold;
@DoNotSub private int size = 0;
private int[] entries;
private final KeySet keySet;
private final Values values;
private final Set> entrySet;
public Int2IntHashMap(final int missingValue)
{
this(16, 0.67f, missingValue);
}
@SuppressWarnings("unchecked")
public Int2IntHashMap(
@DoNotSub final int initialCapacity,
@DoNotSub final float loadFactor,
final int missingValue)
{
validateLoadFactor(loadFactor);
this.loadFactor = loadFactor;
this.missingValue = missingValue;
capacity(BitUtil.findNextPositivePowerOfTwo(initialCapacity));
keySet = new KeySet();
values = new Values();
entrySet = new EntrySet();
}
/**
* The value to be used as a null marker in the map.
*
* @return value to be used as a null marker in the map.
*/
public int missingValue()
{
return missingValue;
}
/**
* Get the load factor applied for resize operations.
*
* @return the load factor applied for resize operations.
*/
public float loadFactor()
{
return loadFactor;
}
/**
* {@inheritDoc}
*/
@DoNotSub public int size()
{
return size;
}
/**
* {@inheritDoc}
*/
public boolean isEmpty()
{
return size == 0;
}
public int get(final int key)
{
final int[] entries = this.entries;
final int missingValue = this.missingValue;
@DoNotSub final int mask = entries.length - 1;
@DoNotSub int index = Hashing.evenHash(key, mask);
int value = missingValue;
int candidateKey;
while ((candidateKey = entries[index]) != missingValue)
{
if (candidateKey == key)
{
value = entries[index + 1];
break;
}
index = next(index, mask);
}
return value;
}
public int put(final int key, final int value)
{
final int[] entries = this.entries;
final int missingValue = this.missingValue;
@DoNotSub final int mask = entries.length - 1;
@DoNotSub int index = Hashing.evenHash(key, mask);
int oldValue = missingValue;
int candidateKey;
while ((candidateKey = entries[index]) != missingValue)
{
if (candidateKey == key)
{
oldValue = entries[index + 1];
break;
}
index = next(index, mask);
}
if (oldValue == missingValue)
{
++size;
entries[index] = key;
}
entries[index + 1] = value;
increaseCapacity();
return oldValue;
}
private void increaseCapacity()
{
if (size > resizeThreshold)
{
// entries.length = 2 * capacity
@DoNotSub final int newCapacity = entries.length;
rehash(newCapacity);
}
}
private void rehash(@DoNotSub final int newCapacity)
{
final int[] oldEntries = entries;
final int missingValue = this.missingValue;
@DoNotSub final int length = entries.length;
capacity(newCapacity);
for (@DoNotSub int i = 0; i < length; i += 2)
{
final int key = oldEntries[i];
if (key != missingValue)
{
put(key, oldEntries[i + 1]);
}
}
}
/**
* Primitive specialised forEach implementation.
*
* NB: Renamed from forEach to avoid overloading on parameter types of lambda
* expression, which doesn't interplay well with type inference in lambda expressions.
*
* @param consumer a callback called for each key/value pair in the map.
*/
public void intForEach(final IntIntConsumer consumer)
{
final int[] entries = this.entries;
final int missingValue = this.missingValue;
@DoNotSub final int length = entries.length;
for (@DoNotSub int i = 0; i < length; i += 2)
{
final int key = entries[i];
if (key != missingValue)
{
consumer.accept(entries[i], entries[i + 1]);
}
}
}
/**
* Int primitive specialised containsKey.
*
* @param key the key to check.
* @return true if the map contains key as a key, false otherwise.
*/
public boolean containsKey(final int key)
{
return get(key) != missingValue;
}
public boolean containsValue(final int value)
{
final int[] entries = this.entries;
@DoNotSub final int length = entries.length;
boolean found = false;
for (@DoNotSub int i = 1; i < length; i += 2)
{
if (value == entries[i])
{
found = true;
break;
}
}
return found;
}
/**
* {@inheritDoc}
*/
public void clear()
{
Arrays.fill(entries, missingValue);
size = 0;
}
/**
* Compact the backing arrays by rehashing with a capacity just larger than current size
* and giving consideration to the load factor.
*/
public void compact()
{
@DoNotSub final int idealCapacity = (int)Math.round(size() * (1.0d / loadFactor));
rehash(BitUtil.findNextPositivePowerOfTwo(idealCapacity));
}
// ---------------- Boxed Versions Below ----------------
/**
* {@inheritDoc}
*/
public Integer get(final Object key)
{
return get((int)key);
}
/**
* {@inheritDoc}
*/
public Integer put(final Integer key, final Integer value)
{
return put((int)key, (int)value);
}
/**
* {@inheritDoc}
*/
public void forEach(final BiConsumer action)
{
intForEach(action::accept);
}
/**
* {@inheritDoc}
*/
public boolean containsKey(final Object key)
{
return containsKey((int)key);
}
/**
* {@inheritDoc}
*/
public boolean containsValue(final Object value)
{
return containsValue((int)value);
}
/**
* {@inheritDoc}
*/
public void putAll(final Map map)
{
for (final Map.Entry entry : map.entrySet())
{
put(entry.getKey(), entry.getValue());
}
}
/**
* {@inheritDoc}
*/
public KeySet keySet()
{
return keySet;
}
/**
* {@inheritDoc}
*/
public Values values()
{
return values;
}
/**
* {@inheritDoc}
*/
public Set> entrySet()
{
return entrySet;
}
/**
* {@inheritDoc}
*/
public Integer remove(final Object key)
{
return remove((int)key);
}
public int remove(final int key)
{
final int[] entries = this.entries;
final int missingValue = this.missingValue;
@DoNotSub final int mask = entries.length - 1;
@DoNotSub int index = Hashing.evenHash(key, mask);
int oldValue = missingValue;
int candidateKey;
while ((candidateKey = entries[index]) != missingValue)
{
if (candidateKey == key)
{
@DoNotSub final int valueIndex = index + 1;
oldValue = entries[valueIndex];
entries[index] = missingValue;
entries[valueIndex] = missingValue;
size--;
compactChain(index);
break;
}
index = next(index, mask);
}
return oldValue;
}
private void compactChain(@DoNotSub int deleteIndex)
{
final int[] entries = this.entries;
final int missingValue = this.missingValue;
@DoNotSub final int mask = entries.length - 1;
@DoNotSub int index = deleteIndex;
while (true)
{
index = next(index, mask);
if (entries[index] == missingValue)
{
break;
}
@DoNotSub final int hash = Hashing.evenHash(entries[index], mask);
if ((index < hash && (hash <= deleteIndex || deleteIndex <= index)) ||
(hash <= deleteIndex && deleteIndex <= index))
{
entries[deleteIndex] = entries[index];
entries[deleteIndex + 1] = entries[index + 1];
entries[index] = missingValue;
entries[index + 1] = missingValue;
deleteIndex = index;
}
}
}
/**
* Get the minimum value stored in the map. If the map is empty then it will return {@link #missingValue()}
*
* @return the minimum value stored in the map.
*/
public int minValue()
{
final int missingValue = this.missingValue;
int min = size == 0 ? missingValue : Integer.MAX_VALUE;
final int[] entries = this.entries;
@DoNotSub final int length = entries.length;
for (@DoNotSub int i = 1; i < length; i += 2)
{
final int value = entries[i];
if (value != missingValue)
{
min = Math.min(min, value);
}
}
return min;
}
/**
* Get the maximum value stored in the map. If the map is empty then it will return {@link #missingValue()}
*
* @return the maximum value stored in the map.
*/
public int maxValue()
{
final int missingValue = this.missingValue;
int max = size == 0 ? missingValue : Integer.MIN_VALUE;
final int[] entries = this.entries;
@DoNotSub final int length = entries.length;
for (@DoNotSub int i = 1; i < length; i += 2)
{
final int value = entries[i];
if (value != missingValue)
{
max = Math.max(max, value);
}
}
return max;
}
/**
* {@inheritDoc}
*/
public String toString()
{
final StringBuilder sb = new StringBuilder();
sb.append('{');
for (final Entry entry : entrySet())
{
sb.append(entry.getKey().intValue());
sb.append('=');
sb.append(entry.getValue().intValue());
sb.append(", ");
}
if (sb.length() > 1)
{
sb.setLength(sb.length() - 2);
}
sb.append('}');
return sb.toString();
}
/**
* Primitive specialised version of {@link #replace(Object, Object)}
*
* @param key key with which the specified value is associated
* @param value value to be associated with the specified key
* @return the previous value associated with the specified key, or
* {@link #missingValue()} if there was no mapping for the key.
*/
public int replace(final int key, final int value)
{
int curValue = get(key);
if (curValue != missingValue)
{
curValue = put(key, value);
}
return curValue;
}
/**
* Primitive specialised version of {@link #replace(Object, Object, Object)}
*
* @param key key with which the specified value is associated
* @param oldValue value expected to be associated with the specified key
* @param newValue value to be associated with the specified key
* @return {@code true} if the value was replaced
*/
public boolean replace(final int key, int oldValue, int newValue)
{
final int curValue = get(key);
if (curValue != oldValue || curValue == missingValue)
{
return false;
}
put(key, newValue);
return true;
}
@DoNotSub private static int next(final int index, final int mask)
{
return (index + 2) & mask;
}
private void capacity(@DoNotSub int newCapacity)
{
@DoNotSub final int entriesLength = newCapacity * 2;
if (entriesLength < 0)
{
throw new IllegalStateException("Max capacity reached at size=" + size);
}
/*@DoNotSub*/ resizeThreshold = (int)(newCapacity * loadFactor);
entries = new int[entriesLength];
size = 0;
Arrays.fill(entries, missingValue);
}
// ---------------- Utility Classes ----------------
abstract class AbstractIterator
{
@DoNotSub private int positionCounter;
@DoNotSub private int stopCounter;
AbstractIterator()
{
reset();
}
private void reset()
{
final int missingValue = Int2IntHashMap.this.missingValue;
final int[] entries = Int2IntHashMap.this.entries;
@DoNotSub final int capacity = entries.length;
@DoNotSub int i = capacity;
if (entries[capacity - 2] != missingValue)
{
i = 0;
for (@DoNotSub int size = capacity; i < size; i += 2)
{
if (entries[i] == missingValue)
{
break;
}
}
}
stopCounter = i;
positionCounter = i + capacity;
}
@DoNotSub protected int keyPosition()
{
return positionCounter & entries.length - 1;
}
public boolean hasNext()
{
final int[] entries = Int2IntHashMap.this.entries;
final int missingValue = Int2IntHashMap.this.missingValue;
@DoNotSub final int mask = entries.length - 1;
boolean hasNext = false;
for (@DoNotSub int i = positionCounter - 2; i >= stopCounter; i -= 2)
{
@DoNotSub final int index = i & mask;
if (entries[index] != missingValue)
{
hasNext = true;
break;
}
}
return hasNext;
}
protected void findNext()
{
final int[] entries = Int2IntHashMap.this.entries;
final int missingValue = Int2IntHashMap.this.missingValue;
@DoNotSub final int mask = entries.length - 1;
for (@DoNotSub int i = positionCounter - 2; i >= stopCounter; i -= 2)
{
@DoNotSub final int index = i & mask;
if (entries[index] != missingValue)
{
positionCounter = i;
return;
}
}
throw new NoSuchElementException();
}
}
public final class IntIterator extends AbstractIterator implements Iterator
{
@DoNotSub private final int offset;
private IntIterator(
@DoNotSub final int offset)
{
this.offset = offset;
}
public Integer next()
{
return nextValue();
}
public int nextValue()
{
findNext();
return entries[keyPosition() + offset];
}
public IntIterator reset()
{
super.reset();
return this;
}
}
final class EntryIterator
extends AbstractIterator
implements Iterator>, Entry
{
private int key;
private int value;
private EntryIterator()
{
super();
}
public Integer getKey()
{
return key;
}
public Integer getValue()
{
return value;
}
public Integer setValue(final Integer value)
{
throw new UnsupportedOperationException();
}
public Entry next()
{
findNext();
@DoNotSub final int keyPosition = keyPosition();
key = entries[keyPosition];
value = entries[keyPosition + 1];
return this;
}
public EntryIterator reset()
{
super.reset();
key = missingValue;
value = missingValue;
return this;
}
}
public final class KeySet extends MapDelegatingSet
{
private final IntIterator keyIterator = new IntIterator(0);
private KeySet()
{
super(Int2IntHashMap.this);
}
/**
* {@inheritDoc}
*/
public IntIterator iterator()
{
return keyIterator.reset();
}
/**
* {@inheritDoc}
*/
public boolean contains(final Object o)
{
return contains((int)o);
}
public boolean contains(final int key)
{
return containsKey(key);
}
}
public final class Values extends AbstractCollection
{
private final IntIterator valueIterator = new IntIterator(1);
private Values()
{
}
/**
* {@inheritDoc}
*/
public IntIterator iterator()
{
return valueIterator.reset();
}
/**
* {@inheritDoc}
*/
@DoNotSub public int size()
{
return Int2IntHashMap.this.size();
}
/**
* {@inheritDoc}
*/
public boolean contains(final Object o)
{
return contains((int)o);
}
public boolean contains(final int key)
{
return containsValue(key);
}
}
private final class EntrySet extends MapDelegatingSet>
{
private final EntryIterator entryIterator = new EntryIterator();
private EntrySet()
{
super(Int2IntHashMap.this);
}
/**
* {@inheritDoc}
*/
public Iterator> iterator()
{
return entryIterator.reset();
}
/**
* {@inheritDoc}
*/
public boolean contains(final Object o)
{
return containsKey(((Entry)o).getKey());
}
}
}