com.badlogic.gdx.utils
Class IntIntMap

java.lang.Object
  com.badlogic.gdx.utils.IntIntMap

public class IntIntMap
extends Object

An unordered map where the keys and values are ints. This implementation is a cuckoo hash map using 3 hashes, random walking, and a small stash for problematic keys. No allocation is done except when growing the table size.

This map performs very fast get, containsKey, and remove (typically O(1), worst case O(log(n))). Put may be a bit slower, depending on hash collisions. Load factors greater than 0.91 greatly increase the chances the map will have to rehash to the next higher POT size.

Author:

Nathan Sweet

Nested Class Summary

static class	IntIntMap.Entries
static class	IntIntMap.Entry<K>
static class	IntIntMap.Keys
static class	IntIntMap.Values

Field Summary

int

size

Constructor Summary

IntIntMap()
Creates a new map with an initial capacity of 32 and a load factor of 0.8.

IntIntMap(int initialCapacity)
Creates a new map with a load factor of 0.8.

IntIntMap(int initialCapacity, float loadFactor)
Creates a new map with the specified initial capacity and load factor.

Method Summary

void	clear()
void	clear(int maximumCapacity) Clears the map and reduces the size of the backing arrays to be the specified capacity if they are larger.
boolean	containsKey(int key)
boolean	containsValue(int value) Returns true if the specified value is in the map.
void	ensureCapacity(int additionalCapacity) Increases the size of the backing array to acommodate the specified number of additional items.
IntIntMap.Entries	entries() Returns an iterator for the entries in the map.
int	findKey(int value, int notFound) Returns the key for the specified value, or null if it is not in the map.
int	get(int key, int defaultValue)
int	getAndIncrement(int key, int defaultValue, int increment) Returns the key's current value and increments the stored value.
IntIntMap.Keys	keys() Returns an iterator for the keys in the map.
void	put(int key, int value)
void	putAll(IntIntMap map)
int	remove(int key, int defaultValue)
void	shrink(int maximumCapacity) Reduces the size of the backing arrays to be the specified capacity or less.
String	toString()
IntIntMap.Values	values() Returns an iterator for the values in the map.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

size

public int size

Constructor Detail

IntIntMap

public IntIntMap()

Creates a new map with an initial capacity of 32 and a load factor of 0.8. This map will hold 25 items before growing the backing table.

IntIntMap

public IntIntMap(int initialCapacity)

Creates a new map with a load factor of 0.8. This map will hold initialCapacity * 0.8 items before growing the backing table.

IntIntMap

public IntIntMap(int initialCapacity,
                 float loadFactor)

Creates a new map with the specified initial capacity and load factor. This map will hold initialCapacity * loadFactor items before growing the backing table.

Method Detail

put

public void put(int key,
                int value)

putAll

public void putAll(IntIntMap map)

get

public int get(int key,
               int defaultValue)

Parameters:

defaultValue - Returned if the key was not associated with a value.

getAndIncrement

public int getAndIncrement(int key,
                           int defaultValue,
                           int increment)

Returns the key's current value and increments the stored value. If the key is not in the map, defaultValue + increment is put into the map.

remove

public int remove(int key,
                  int defaultValue)

shrink

public void shrink(int maximumCapacity)

Reduces the size of the backing arrays to be the specified capacity or less. If the capacity is already less, nothing is done. If the map contains more items than the specified capacity, the next highest power of two capacity is used instead.

clear

public void clear(int maximumCapacity)

Clears the map and reduces the size of the backing arrays to be the specified capacity if they are larger.

clear

public void clear()

containsValue

public boolean containsValue(int value)

Returns true if the specified value is in the map. Note this traverses the entire map and compares every value, which may be an expensive operation.

containsKey

public boolean containsKey(int key)

findKey

public int findKey(int value,
                   int notFound)

Returns the key for the specified value, or null if it is not in the map. Note this traverses the entire map and compares every value, which may be an expensive operation.

ensureCapacity

public void ensureCapacity(int additionalCapacity)

Increases the size of the backing array to acommodate the specified number of additional items. Useful before adding many items to avoid multiple backing array resizes.

toString

public String toString()

Overrides:

toString in class Object

entries

public IntIntMap.Entries entries()

Returns an iterator for the entries in the map. Remove is supported. Note that the same iterator instance is returned each time this method is called. Use the IntFloatMap.Entries constructor for nested or multithreaded iteration.

values

public IntIntMap.Values values()

Returns an iterator for the values in the map. Remove is supported. Note that the same iterator instance is returned each time this method is called. Use the IntFloatMap.Entries constructor for nested or multithreaded iteration.

keys

public IntIntMap.Keys keys()

Returns an iterator for the keys in the map. Remove is supported. Note that the same iterator instance is returned each time this method is called. Use the IntFloatMap.Entries constructor for nested or multithreaded iteration.