/**
* Removes the given key with its associated element from the receiver, if present.
*
* @param key the key to be removed from the receiver.
* @return <tt>true</tt> if the receiver contained the specified key, <tt>false</tt> otherwise.
*/
public boolean removeKey(int key) {
int i = indexOfKey(key);
if (i < 0) return false; // key not contained
// if (debug) if (this.state[i] == FREE) throw new InternalError();
// if (debug) if (this.state[i] == REMOVED) throw new InternalError();
this.state[i] = REMOVED;
// this.values[i]=0; // delta
// if (debug) this.table[i]=Integer.MAX_VALUE; // delta
// if (debug) this.values[i]=Double.NaN; // delta
this.distinct--;
if (this.distinct < this.lowWaterMark) {
int newCapacity = chooseShrinkCapacity(this.distinct, this.minLoadFactor, this.maxLoadFactor);
/*
* if (table.length != newCapacity) { System.out.print("shrink rehashing ");
* System.out.println
* ("at distinct="+distinct+", capacity="+table.length+" to newCapacity="+newCapacity+" ...");
* }
*/
rehash(newCapacity);
}
return true;
}
/**
* Trims the capacity of the receiver to be the receiver's current size. Releases any superfluous
* internal memory. An application can use this operation to minimize the storage of the receiver.
*/
public void trimToSize() {
// * 1.2 because open addressing's performance exponentially degrades beyond that point
// so that even rehashing the table can take very long
int newCapacity = nextPrime((int) (1 + 1.2 * size()));
if (table.length > newCapacity) {
rehash(newCapacity);
}
}
/**
* Associates the given key with the given value. Replaces any old <tt>(key,someOtherValue)</tt>
* association, if existing.
*
* @param key the key the value shall be associated with.
* @param value the value to be associated.
* @return <tt>true</tt> if the receiver did not already contain such a key; <tt>false</tt> if the
* receiver did already contain such a key - the new value has now replaced the formerly
* associated value.
*/
public boolean put(int key, double value) {
int i = indexOfInsertion(key);
if (i < 0) { // already contained
i = -i - 1;
// if (debug) if (this.state[i] != FULL) throw new InternalError();
// if (debug) if (this.table[i] != key) throw new InternalError();
this.values[i] = value;
return false;
}
if (this.distinct > this.highWaterMark) {
int newCapacity =
chooseGrowCapacity(this.distinct + 1, this.minLoadFactor, this.maxLoadFactor);
/*
* System.out.print("grow rehashing ");
* System.out.println("at distinct="+distinct+", capacity="
* +table.length+" to newCapacity="+newCapacity+" ...");
*/
rehash(newCapacity);
return put(key, value);
}
this.table[i] = key;
this.values[i] = value;
if (this.state[i] == FREE) this.freeEntries--;
this.state[i] = FULL;
this.distinct++;
if (this.freeEntries < 1) { // delta
int newCapacity =
chooseGrowCapacity(this.distinct + 1, this.minLoadFactor, this.maxLoadFactor);
rehash(newCapacity);
}
return true;
}
/**
* Ensures that the receiver can hold at least the specified number of associations without
* needing to allocate new internal memory. If necessary, allocates new internal memory and
* increases the capacity of the receiver.
*
* <p>This method never need be called; it is for performance tuning only. Calling this method
* before <tt>put()</tt>ing a large number of associations boosts performance, because the
* receiver will grow only once instead of potentially many times and hash collisions get less
* probable.
*
* @param minCapacity the desired minimum capacity.
*/
public void ensureCapacity(int minCapacity) {
if (table.length < minCapacity) {
int newCapacity = nextPrime(minCapacity);
rehash(newCapacity);
}
}
