/**
* 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,
* nothing is done.
*/
public void shrink(int maximumCapacity) {
if (maximumCapacity < 0)
throw new IllegalArgumentException("maximumCapacity must be >= 0: " + maximumCapacity);
if (size > maximumCapacity) maximumCapacity = size;
if (capacity <= maximumCapacity) return;
maximumCapacity = ObjectMap.nextPowerOfTwo(maximumCapacity);
resize(maximumCapacity);
}
/**
* Creates a new map with the specified initial capacity and load factor. This map will hold
* initialCapacity * loadFactor items before growing the backing table.
*/
public IdentityMap(int initialCapacity, float loadFactor) {
if (initialCapacity < 0)
throw new IllegalArgumentException("initialCapacity must be >= 0: " + initialCapacity);
if (capacity > 1 << 30)
throw new IllegalArgumentException("initialCapacity is too large: " + initialCapacity);
capacity = ObjectMap.nextPowerOfTwo(initialCapacity);
if (loadFactor <= 0)
throw new IllegalArgumentException("loadFactor must be > 0: " + loadFactor);
this.loadFactor = loadFactor;
threshold = (int) (capacity * loadFactor);
mask = capacity - 1;
hashShift = 31 - Integer.numberOfTrailingZeros(capacity);
stashCapacity = Math.max(3, (int) Math.ceil(Math.log(capacity)) * 2);
pushIterations = Math.max(Math.min(capacity, 8), (int) Math.sqrt(capacity) / 8);
keyTable = (K[]) new Object[capacity + stashCapacity];
valueTable = (V[]) new Object[keyTable.length];
}
/**
* 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.
*/
public void ensureCapacity(int additionalCapacity) {
int sizeNeeded = size + additionalCapacity;
if (sizeNeeded >= threshold) resize(ObjectMap.nextPowerOfTwo((int) (sizeNeeded / loadFactor)));
}