Package com.esotericsoftware.kryo.util
Class IntMap<V>
- java.lang.Object
-
- com.esotericsoftware.kryo.util.IntMap<V>
-
public class IntMap<V> extends java.lang.ObjectAn unordered map that uses int keys. This implementation is a cuckoo hash map using 3 hashes (if table size is less than 2^16) or 4 hashes (if table size is greater than or equal to 2^16), random walking, and a small stash for problematic keys. Null values are allowed. 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.
-
-
Nested Class Summary
Nested Classes Modifier and Type Class Description static classIntMap.Entries<V>static classIntMap.Entry<V>static classIntMap.Keysprivate static classIntMap.MapIterator<V>static classIntMap.Values<V>
-
Field Summary
Fields Modifier and Type Field Description private booleanbigTable(package private) intcapacityprivate static intEMPTYprivate inthashShift(package private) booleanhasZeroValue(package private) int[]keyTableprivate floatloadFactorprivate intmaskprivate static intPRIME2private static intPRIME3private static intPRIME4private intpushIterationsintsizeprivate intstashCapacity(package private) intstashSizeprivate intthreshold(package private) V[]valueTable(package private) VzeroValue
-
Constructor Summary
Constructors Constructor Description IntMap()Creates a new map with an initial capacity of 32 and a load factor of 0.8.IntMap(int initialCapacity)Creates a new map with a load factor of 0.8.IntMap(int initialCapacity, float loadFactor)Creates a new map with the specified initial capacity and load factor.IntMap(IntMap<? extends V> map)Creates a new map identical to the specified map.
-
Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description voidclear()voidclear(int maximumCapacity)Clears the map and reduces the size of the backing arrays to be the specified capacity if they are larger.booleancontainsKey(int key)private booleancontainsKeyStash(int key)booleancontainsValue(java.lang.Object value, boolean identity)Returns true if the specified value is in the map.voidensureCapacity(int additionalCapacity)Increases the size of the backing array to acommodate the specified number of additional items.IntMap.Entries<V>entries()Returns an iterator for the entries in the map.intfindKey(java.lang.Object value, boolean identity, int notFound)Returns the key for the specified value, or notFound if it is not in the map.Vget(int key)Vget(int key, V defaultValue)private VgetStash(int key, V defaultValue)private inthash2(int h)private inthash3(int h)private inthash4(int h)IntMap.Keyskeys()Returns an iterator for the keys in the map.private voidpush(int insertKey, V insertValue, int index1, int key1, int index2, int key2, int index3, int key3, int index4, int key4)Vput(int key, V value)voidputAll(IntMap<V> map)private voidputResize(int key, V value)Skips checks for existing keys.private voidputStash(int key, V value)Vremove(int key)(package private) VremoveStash(int key)(package private) voidremoveStashIndex(int index)private voidresize(int newSize)voidshrink(int maximumCapacity)Reduces the size of the backing arrays to be the specified capacity or less.java.lang.StringtoString()IntMap.Values<V>values()Returns an iterator for the values in the map.
-
-
-
Field Detail
-
PRIME2
private static final int PRIME2
- See Also:
- Constant Field Values
-
PRIME3
private static final int PRIME3
- See Also:
- Constant Field Values
-
PRIME4
private static final int PRIME4
- See Also:
- Constant Field Values
-
EMPTY
private static final int EMPTY
- See Also:
- Constant Field Values
-
size
public int size
-
keyTable
int[] keyTable
-
valueTable
V[] valueTable
-
capacity
int capacity
-
stashSize
int stashSize
-
zeroValue
V zeroValue
-
hasZeroValue
boolean hasZeroValue
-
loadFactor
private float loadFactor
-
hashShift
private int hashShift
-
mask
private int mask
-
threshold
private int threshold
-
stashCapacity
private int stashCapacity
-
pushIterations
private int pushIterations
-
bigTable
private boolean bigTable
-
-
Constructor Detail
-
IntMap
public IntMap()
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.
-
IntMap
public IntMap(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.
-
IntMap
public IntMap(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
-
putResize
private void putResize(int key, V value)Skips checks for existing keys.
-
push
private void push(int insertKey, V insertValue, int index1, int key1, int index2, int key2, int index3, int key3, int index4, int key4)
-
putStash
private void putStash(int key, V value)
-
get
public V get(int key)
-
remove
public V remove(int key)
-
removeStash
V removeStash(int key)
-
removeStashIndex
void removeStashIndex(int index)
-
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(java.lang.Object value, boolean identity)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.- Parameters:
identity- If true, uses == to compare the specified value with values in the map. If false, usesObject.equals(Object).
-
containsKey
public boolean containsKey(int key)
-
containsKeyStash
private boolean containsKeyStash(int key)
-
findKey
public int findKey(java.lang.Object value, boolean identity, int notFound)Returns the key for the specified value, or notFound if it is not in the map. Note this traverses the entire map and compares every value, which may be an expensive operation.- Parameters:
identity- If true, uses == to compare the specified value with values in the map. If false, usesObject.equals(Object).
-
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.
-
resize
private void resize(int newSize)
-
hash2
private int hash2(int h)
-
hash3
private int hash3(int h)
-
hash4
private int hash4(int h)
-
toString
public java.lang.String toString()
- Overrides:
toStringin classjava.lang.Object
-
entries
public IntMap.Entries<V> 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 theIntMap.Entriesconstructor for nested or multithreaded iteration.
-
values
public IntMap.Values<V> 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 theIntMap.Entriesconstructor for nested or multithreaded iteration.
-
keys
public IntMap.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 theIntMap.Entriesconstructor for nested or multithreaded iteration.
-
-