http://fastutil.di.unimi.it/: fastutil extends the Java Collections Framework by providing type-specific maps, sets, lists and priority queues with a small memory footprint and fast access and insertion; provides also big (64-bit) arrays, sets and lists, and fast, practical I/O classes for binary and text files.
  • Sebastiano Vigna 
/*
	* Copyright (C) 2002-2019 Sebastiano Vigna
	*
	* 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 it.unimi.dsi.fastutil.shorts;
import it.unimi.dsi.fastutil.Hash;
import it.unimi.dsi.fastutil.HashCommon;
import static it.unimi.dsi.fastutil.HashCommon.arraySize;
import static it.unimi.dsi.fastutil.HashCommon.maxFill;
import java.util.Map;
import java.util.Arrays;
import java.util.NoSuchElementException;
import java.util.function.Consumer;
import it.unimi.dsi.fastutil.doubles.DoubleCollection;
import it.unimi.dsi.fastutil.doubles.AbstractDoubleCollection;
import it.unimi.dsi.fastutil.doubles.DoubleIterator;
import java.util.Comparator;
import it.unimi.dsi.fastutil.doubles.DoubleListIterator;
import it.unimi.dsi.fastutil.objects.AbstractObjectSortedSet;
import it.unimi.dsi.fastutil.objects.ObjectListIterator;
import it.unimi.dsi.fastutil.objects.ObjectBidirectionalIterator;
import it.unimi.dsi.fastutil.objects.ObjectSortedSet;

A type-specific linked hash map with with a fast, small-footprint
implementation.


Instances of this class use a hash table to represent a map. The table is
filled up to a specified load factor, and then doubled in size to
accommodate new entries. If the table is emptied below one fourth of
the load factor, it is halved in size; however, the table is never reduced to
a size smaller than that at creation time: this approach makes it possible to
create maps with a large capacity in which insertions and deletions do not
cause immediately rehashing. Moreover, halving is not performed when deleting
entries from an iterator, as it would interfere with the iteration process.

 Note that clear() does not modify the hash table size. Rather, a family of trimming methods lets you control the size of the table; this is particularly useful if you reuse instances of this class. 

Iterators generated by this map will enumerate pairs in the same order in
which they have been added to the map (addition of pairs whose key is already
present in the map does not change the iteration order). Note that this order
has nothing in common with the natural order of the keys. The order is kept
by means of a doubly linked list, represented via an array of longs
parallel to the table.

 This class implements the interface of a sorted map, so to allow easy access of the iteration order: for instance, you can get the first key in iteration order with firstKey() without having to create an iterator; however, this class partially violates the SortedMap contract because all submap methods throw an exception and comparator() returns always null. 
 Additional methods, such as getAndMoveToFirst(), make it easy to use instances of this class as a cache (e.g., with LRU policy). 
 The iterators provided by the views of this class using are type-specific list iterators, and can be started at any element which is a key of the map, or a NoSuchElementException exception will be thrown. If, however, the provided element is not the first or last key in the map, the first access to the list index will require linear time, as in the worst case the entire key set must be scanned in iteration order to retrieve the positional index of the starting key. If you use just the methods of a type-specific BidirectionalIterator, however, all operations will be performed in constant time. 
See Also:
/**
 * A type-specific linked hash map with with a fast, small-footprint
 * implementation.
 *
 * <p>
 * Instances of this class use a hash table to represent a map. The table is
 * filled up to a specified <em>load factor</em>, and then doubled in size to
 * accommodate new entries. If the table is emptied below <em>one fourth</em> of
 * the load factor, it is halved in size; however, the table is never reduced to
 * a size smaller than that at creation time: this approach makes it possible to
 * create maps with a large capacity in which insertions and deletions do not
 * cause immediately rehashing. Moreover, halving is not performed when deleting
 * entries from an iterator, as it would interfere with the iteration process.
 *
 * <p>
 * Note that {@link #clear()} does not modify the hash table size. Rather, a
 * family of {@linkplain #trim() trimming methods} lets you control the size of
 * the table; this is particularly useful if you reuse instances of this class.
 *
 * <p>
 * Iterators generated by this map will enumerate pairs in the same order in
 * which they have been added to the map (addition of pairs whose key is already
 * present in the map does not change the iteration order). Note that this order
 * has nothing in common with the natural order of the keys. The order is kept
 * by means of a doubly linked list, represented <i>via</i> an array of longs
 * parallel to the table.
 *
 * <p>
 * This class implements the interface of a sorted map, so to allow easy access
 * of the iteration order: for instance, you can get the first key in iteration
 * order with {@code firstKey()} without having to create an iterator; however,
 * this class partially violates the {@link java.util.SortedMap} contract
 * because all submap methods throw an exception and {@link #comparator()}
 * returns always {@code null}.
 *
 * <p>
 * Additional methods, such as {@code getAndMoveToFirst()}, make it easy to use
 * instances of this class as a cache (e.g., with LRU policy).
 *
 * <p>
 * The iterators provided by the views of this class using are type-specific
 * {@linkplain java.util.ListIterator list iterators}, and can be started at any
 * element <em>which is a key of the map</em>, or a
 * {@link NoSuchElementException} exception will be thrown. If, however, the
 * provided element is not the first or last key in the map, the first access to
 * the list index will require linear time, as in the worst case the entire key
 * set must be scanned in iteration order to retrieve the positional index of
 * the starting key. If you use just the methods of a type-specific
 * {@link it.unimi.dsi.fastutil.BidirectionalIterator}, however, all operations
 * will be performed in constant time.
 *
 * @see Hash
 * @see HashCommon
 */
public class Short2DoubleLinkedOpenHashMap extends AbstractShort2DoubleSortedMap
		implements
			java.io.Serializable,
			Cloneable,
			Hash {
	private static final long serialVersionUID = 0L;
	private static final boolean ASSERTS = false;
	
The array of keys. 
/** The array of keys. */
	protected transient short[] key;
	
The array of values. 
/** The array of values. */
	protected transient double[] value;
	
The mask for wrapping a position counter. 
/** The mask for wrapping a position counter. */
	protected transient int mask;
	
Whether this map contains the key zero. 
/** Whether this map contains the key zero. */
	protected transient boolean containsNullKey;
	
The index of the first entry in iteration order. It is valid iff size is nonzero; otherwise, it contains -1. 
/**
	 * The index of the first entry in iteration order. It is valid iff
	 * {@link #size} is nonzero; otherwise, it contains -1.
	 */
	protected transient int first = -1;
	
The index of the last entry in iteration order. It is valid iff size is nonzero; otherwise, it contains -1. 
/**
	 * The index of the last entry in iteration order. It is valid iff {@link #size}
	 * is nonzero; otherwise, it contains -1.
	 */
	protected transient int last = -1;
	
For each entry, the next and the previous entry in iteration order, stored as ((prev & 0xFFFFFFFFL) << 32) | (next & 0xFFFFFFFFL). The first entry contains predecessor -1, and the last entry contains successor -1. 
/**
	 * For each entry, the next and the previous entry in iteration order, stored as
	 * {@code ((prev & 0xFFFFFFFFL) << 32) | (next & 0xFFFFFFFFL)}. The first entry
	 * contains predecessor -1, and the last entry contains successor -1.
	 */
	protected transient long[] link;
	
The current table size. 
/** The current table size. */
	protected transient int n;
	
Threshold after which we rehash. It must be the table size times f. 
/**
	 * Threshold after which we rehash. It must be the table size times {@link #f}.
	 */
	protected transient int maxFill;
	
We never resize below this threshold, which is the construction-time {#n}.

/**
	 * We never resize below this threshold, which is the construction-time {#n}.
	 */
	protected final transient int minN;
	
Number of entries in the set (including the key zero, if present). 
/** Number of entries in the set (including the key zero, if present). */
	protected int size;
	
The acceptable load factor. 
/** The acceptable load factor. */
	protected final float f;
	
Cached set of entries. 
/** Cached set of entries. */
	protected transient FastSortedEntrySet entries;
	
Cached set of keys. 
/** Cached set of keys. */
	protected transient ShortSortedSet keys;
	
Cached collection of values. 
/** Cached collection of values. */
	protected transient DoubleCollection values;
	
Creates a new hash map.

 The actual table size will be the least power of two greater than expected/f. 
Params:
  • expected – 
           the expected number of elements in the hash map.
  • f – 
           the load factor.
/**
	 * Creates a new hash map.
	 *
	 * <p>
	 * The actual table size will be the least power of two greater than
	 * {@code expected}/{@code f}.
	 *
	 * @param expected
	 *            the expected number of elements in the hash map.
	 * @param f
	 *            the load factor.
	 */

	public Short2DoubleLinkedOpenHashMap(final int expected, final float f) {
		if (f <= 0 || f > 1)
			throw new IllegalArgumentException("Load factor must be greater than 0 and smaller than or equal to 1");
		if (expected < 0)
			throw new IllegalArgumentException("The expected number of elements must be nonnegative");
		this.f = f;
		minN = n = arraySize(expected, f);
		mask = n - 1;
		maxFill = maxFill(n, f);
		key = new short[n + 1];
		value = new double[n + 1];
		link = new long[n + 1];
	}
	
Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor. 
Params:
  • expected – 
           the expected number of elements in the hash map.
/**
	 * Creates a new hash map with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor.
	 *
	 * @param expected
	 *            the expected number of elements in the hash map.
	 */
	public Short2DoubleLinkedOpenHashMap(final int expected) {
		this(expected, DEFAULT_LOAD_FACTOR);
	}
	
Creates a new hash map with initial expected Hash.DEFAULT_INITIAL_SIZE entries and Hash.DEFAULT_LOAD_FACTOR as load factor. 
/**
	 * Creates a new hash map with initial expected
	 * {@link Hash#DEFAULT_INITIAL_SIZE} entries and
	 * {@link Hash#DEFAULT_LOAD_FACTOR} as load factor.
	 */
	public Short2DoubleLinkedOpenHashMap() {
		this(DEFAULT_INITIAL_SIZE, DEFAULT_LOAD_FACTOR);
	}
	
Creates a new hash map copying a given one.

Params:
  • m –  a Map to be copied into the new hash map.
  • f – 
           the load factor.
/**
	 * Creates a new hash map copying a given one.
	 *
	 * @param m
	 *            a {@link Map} to be copied into the new hash map.
	 * @param f
	 *            the load factor.
	 */
	public Short2DoubleLinkedOpenHashMap(final Map<? extends Short, ? extends Double> m, final float f) {
		this(m.size(), f);
		putAll(m);
	}
	
Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given one. 
Params:
  • m –  a Map to be copied into the new hash map.
/**
	 * Creates a new hash map with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor
	 * copying a given one.
	 *
	 * @param m
	 *            a {@link Map} to be copied into the new hash map.
	 */
	public Short2DoubleLinkedOpenHashMap(final Map<? extends Short, ? extends Double> m) {
		this(m, DEFAULT_LOAD_FACTOR);
	}
	
Creates a new hash map copying a given type-specific one.

Params:
  • m – 
           a type-specific map to be copied into the new hash map.
  • f – 
           the load factor.
/**
	 * Creates a new hash map copying a given type-specific one.
	 *
	 * @param m
	 *            a type-specific map to be copied into the new hash map.
	 * @param f
	 *            the load factor.
	 */
	public Short2DoubleLinkedOpenHashMap(final Short2DoubleMap m, final float f) {
		this(m.size(), f);
		putAll(m);
	}
	
Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific one. 
Params:
  • m – 
           a type-specific map to be copied into the new hash map.
/**
	 * Creates a new hash map with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor
	 * copying a given type-specific one.
	 *
	 * @param m
	 *            a type-specific map to be copied into the new hash map.
	 */
	public Short2DoubleLinkedOpenHashMap(final Short2DoubleMap m) {
		this(m, DEFAULT_LOAD_FACTOR);
	}
	
Creates a new hash map using the elements of two parallel arrays.

Params:
  • k – 
           the array of keys of the new hash map.
  • v – 
           the array of corresponding values in the new hash map.
  • f – 
           the load factor.
Throws:
/**
	 * Creates a new hash map using the elements of two parallel arrays.
	 *
	 * @param k
	 *            the array of keys of the new hash map.
	 * @param v
	 *            the array of corresponding values in the new hash map.
	 * @param f
	 *            the load factor.
	 * @throws IllegalArgumentException
	 *             if {@code k} and {@code v} have different lengths.
	 */
	public Short2DoubleLinkedOpenHashMap(final short[] k, final double[] v, final float f) {
		this(k.length, f);
		if (k.length != v.length)
			throw new IllegalArgumentException(
					"The key array and the value array have different lengths (" + k.length + " and " + v.length + ")");
		for (int i = 0; i < k.length; i++)
			this.put(k[i], v[i]);
	}
	
Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor using the elements of two parallel arrays. 
Params:
  • k – 
           the array of keys of the new hash map.
  • v – 
           the array of corresponding values in the new hash map.
Throws:
/**
	 * Creates a new hash map with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor
	 * using the elements of two parallel arrays.
	 *
	 * @param k
	 *            the array of keys of the new hash map.
	 * @param v
	 *            the array of corresponding values in the new hash map.
	 * @throws IllegalArgumentException
	 *             if {@code k} and {@code v} have different lengths.
	 */
	public Short2DoubleLinkedOpenHashMap(final short[] k, final double[] v) {
		this(k, v, DEFAULT_LOAD_FACTOR);
	}
	private int realSize() {
		return containsNullKey ? size - 1 : size;
	}
	private void ensureCapacity(final int capacity) {
		final int needed = arraySize(capacity, f);
		if (needed > n)
			rehash(needed);
	}
	private void tryCapacity(final long capacity) {
		final int needed = (int) Math.min(1 << 30,
				Math.max(2, HashCommon.nextPowerOfTwo((long) Math.ceil(capacity / f))));
		if (needed > n)
			rehash(needed);
	}
	private double removeEntry(final int pos) {
		final double oldValue = value[pos];
		size--;
		fixPointers(pos);
		shiftKeys(pos);
		if (n > minN && size < maxFill / 4 && n > DEFAULT_INITIAL_SIZE)
			rehash(n / 2);
		return oldValue;
	}
	private double removeNullEntry() {
		containsNullKey = false;
		final double oldValue = value[n];
		size--;
		fixPointers(n);
		if (n > minN && size < maxFill / 4 && n > DEFAULT_INITIAL_SIZE)
			rehash(n / 2);
		return oldValue;
	}
	@Override
	public void putAll(Map<? extends Short, ? extends Double> m) {
		if (f <= .5)
			ensureCapacity(m.size()); // The resulting map will be sized for m.size() elements
		else
			tryCapacity(size() + m.size()); // The resulting map will be tentatively sized for size() + m.size()
											// elements
		super.putAll(m);
	}

	private int find(final short k) {
		if (((k) == ((short) 0)))
			return containsNullKey ? n : -(n + 1);
		short curr;
		final short[] key = this.key;
		int pos;
		// The starting point.
		if (((curr = key[pos = (it.unimi.dsi.fastutil.HashCommon.mix((k))) & mask]) == ((short) 0)))
			return -(pos + 1);
		if (((k) == (curr)))
			return pos;
		// There's always an unused entry.
		while (true) {
			if (((curr = key[pos = (pos + 1) & mask]) == ((short) 0)))
				return -(pos + 1);
			if (((k) == (curr)))
				return pos;
		}
	}
	private void insert(final int pos, final short k, final double v) {
		if (pos == n)
			containsNullKey = true;
		key[pos] = k;
		value[pos] = v;
		if (size == 0) {
			first = last = pos;
			// Special case of SET_UPPER_LOWER(link[pos], -1, -1);
			link[pos] = -1L;
		} else {
			link[last] ^= ((link[last] ^ (pos & 0xFFFFFFFFL)) & 0xFFFFFFFFL);
			link[pos] = ((last & 0xFFFFFFFFL) << 32) | (-1 & 0xFFFFFFFFL);
			last = pos;
		}
		if (size++ >= maxFill)
			rehash(arraySize(size + 1, f));
		if (ASSERTS)
			checkTable();
	}
	@Override
	public double put(final short k, final double v) {
		final int pos = find(k);
		if (pos < 0) {
			insert(-pos - 1, k, v);
			return defRetValue;
		}
		final double oldValue = value[pos];
		value[pos] = v;
		return oldValue;
	}
	private double addToValue(final int pos, final double incr) {
		final double oldValue = value[pos];
		value[pos] = oldValue + incr;
		return oldValue;
	}
	
Adds an increment to value currently associated with a key.

 Note that this method respects the default
return value semantics: when called with a key that does not currently appears in the map, the key will be associated with the default return value plus the given increment. 
Params:
  • k – 
           the key.
  • incr – 
           the increment.
Returns:the old value, or the default
        return value if no value was present for the given key.
/**
	 * Adds an increment to value currently associated with a key.
	 *
	 * <p>
	 * Note that this method respects the {@linkplain #defaultReturnValue() default
	 * return value} semantics: when called with a key that does not currently
	 * appears in the map, the key will be associated with the default return value
	 * plus the given increment.
	 *
	 * @param k
	 *            the key.
	 * @param incr
	 *            the increment.
	 * @return the old value, or the {@linkplain #defaultReturnValue() default
	 *         return value} if no value was present for the given key.
	 */
	public double addTo(final short k, final double incr) {
		int pos;
		if (((k) == ((short) 0))) {
			if (containsNullKey)
				return addToValue(n, incr);
			pos = n;
			containsNullKey = true;
		} else {
			short curr;
			final short[] key = this.key;
			// The starting point.
			if (!((curr = key[pos = (it.unimi.dsi.fastutil.HashCommon.mix((k))) & mask]) == ((short) 0))) {
				if (((curr) == (k)))
					return addToValue(pos, incr);
				while (!((curr = key[pos = (pos + 1) & mask]) == ((short) 0)))
					if (((curr) == (k)))
						return addToValue(pos, incr);
			}
		}
		key[pos] = k;
		value[pos] = defRetValue + incr;
		if (size == 0) {
			first = last = pos;
			// Special case of SET_UPPER_LOWER(link[pos], -1, -1);
			link[pos] = -1L;
		} else {
			link[last] ^= ((link[last] ^ (pos & 0xFFFFFFFFL)) & 0xFFFFFFFFL);
			link[pos] = ((last & 0xFFFFFFFFL) << 32) | (-1 & 0xFFFFFFFFL);
			last = pos;
		}
		if (size++ >= maxFill)
			rehash(arraySize(size + 1, f));
		if (ASSERTS)
			checkTable();
		return defRetValue;
	}
	
Shifts left entries with the specified hash code, starting at the specified
position, and empties the resulting free entry.

Params:
  • pos – 
           a starting position.
/**
	 * Shifts left entries with the specified hash code, starting at the specified
	 * position, and empties the resulting free entry.
	 *
	 * @param pos
	 *            a starting position.
	 */
	protected final void shiftKeys(int pos) {
		// Shift entries with the same hash.
		int last, slot;
		short curr;
		final short[] key = this.key;
		for (;;) {
			pos = ((last = pos) + 1) & mask;
			for (;;) {
				if (((curr = key[pos]) == ((short) 0))) {
					key[last] = ((short) 0);
					return;
				}
				slot = (it.unimi.dsi.fastutil.HashCommon.mix((curr))) & mask;
				if (last <= pos ? last >= slot || slot > pos : last >= slot && slot > pos)
					break;
				pos = (pos + 1) & mask;
			}
			key[last] = curr;
			value[last] = value[pos];
			fixPointers(pos, last);
		}
	}
	@Override

	public double remove(final short k) {
		if (((k) == ((short) 0))) {
			if (containsNullKey)
				return removeNullEntry();
			return defRetValue;
		}
		short curr;
		final short[] key = this.key;
		int pos;
		// The starting point.
		if (((curr = key[pos = (it.unimi.dsi.fastutil.HashCommon.mix((k))) & mask]) == ((short) 0)))
			return defRetValue;
		if (((k) == (curr)))
			return removeEntry(pos);
		while (true) {
			if (((curr = key[pos = (pos + 1) & mask]) == ((short) 0)))
				return defRetValue;
			if (((k) == (curr)))
				return removeEntry(pos);
		}
	}
	private double setValue(final int pos, final double v) {
		final double oldValue = value[pos];
		value[pos] = v;
		return oldValue;
	}
	
Removes the mapping associated with the first key in iteration order.

Throws:
Returns:the value previously associated with the first key in iteration
        order.
/**
	 * Removes the mapping associated with the first key in iteration order.
	 * 
	 * @return the value previously associated with the first key in iteration
	 *         order.
	 * @throws NoSuchElementException
	 *             is this map is empty.
	 */
	public double removeFirstDouble() {
		if (size == 0)
			throw new NoSuchElementException();
		final int pos = first;
		// Abbreviated version of fixPointers(pos)
		first = (int) link[pos];
		if (0 <= first) {
			// Special case of SET_PREV(link[first], -1)
			link[first] |= (-1 & 0xFFFFFFFFL) << 32;
		}
		size--;
		final double v = value[pos];
		if (pos == n) {
			containsNullKey = false;
		} else
			shiftKeys(pos);
		if (n > minN && size < maxFill / 4 && n > DEFAULT_INITIAL_SIZE)
			rehash(n / 2);
		return v;
	}
	
Removes the mapping associated with the last key in iteration order.

Throws:
Returns:the value previously associated with the last key in iteration order.
/**
	 * Removes the mapping associated with the last key in iteration order.
	 * 
	 * @return the value previously associated with the last key in iteration order.
	 * @throws NoSuchElementException
	 *             is this map is empty.
	 */
	public double removeLastDouble() {
		if (size == 0)
			throw new NoSuchElementException();
		final int pos = last;
		// Abbreviated version of fixPointers(pos)
		last = (int) (link[pos] >>> 32);
		if (0 <= last) {
			// Special case of SET_NEXT(link[last], -1)
			link[last] |= -1 & 0xFFFFFFFFL;
		}
		size--;
		final double v = value[pos];
		if (pos == n) {
			containsNullKey = false;
		} else
			shiftKeys(pos);
		if (n > minN && size < maxFill / 4 && n > DEFAULT_INITIAL_SIZE)
			rehash(n / 2);
		return v;
	}
	private void moveIndexToFirst(final int i) {
		if (size == 1 || first == i)
			return;
		if (last == i) {
			last = (int) (link[i] >>> 32);
			// Special case of SET_NEXT(link[last], -1);
			link[last] |= -1 & 0xFFFFFFFFL;
		} else {
			final long linki = link[i];
			final int prev = (int) (linki >>> 32);
			final int next = (int) linki;
			link[prev] ^= ((link[prev] ^ (linki & 0xFFFFFFFFL)) & 0xFFFFFFFFL);
			link[next] ^= ((link[next] ^ (linki & 0xFFFFFFFF00000000L)) & 0xFFFFFFFF00000000L);
		}
		link[first] ^= ((link[first] ^ ((i & 0xFFFFFFFFL) << 32)) & 0xFFFFFFFF00000000L);
		link[i] = ((-1 & 0xFFFFFFFFL) << 32) | (first & 0xFFFFFFFFL);
		first = i;
	}
	private void moveIndexToLast(final int i) {
		if (size == 1 || last == i)
			return;
		if (first == i) {
			first = (int) link[i];
			// Special case of SET_PREV(link[first], -1);
			link[first] |= (-1 & 0xFFFFFFFFL) << 32;
		} else {
			final long linki = link[i];
			final int prev = (int) (linki >>> 32);
			final int next = (int) linki;
			link[prev] ^= ((link[prev] ^ (linki & 0xFFFFFFFFL)) & 0xFFFFFFFFL);
			link[next] ^= ((link[next] ^ (linki & 0xFFFFFFFF00000000L)) & 0xFFFFFFFF00000000L);
		}
		link[last] ^= ((link[last] ^ (i & 0xFFFFFFFFL)) & 0xFFFFFFFFL);
		link[i] = ((last & 0xFFFFFFFFL) << 32) | (-1 & 0xFFFFFFFFL);
		last = i;
	}
	
Returns the value to which the given key is mapped; if the key is present, it
is moved to the first position of the iteration order.

Params:
  • k – 
           the key.
Returns:the corresponding value, or the 
        default return value if no value was present for the given key.
/**
	 * Returns the value to which the given key is mapped; if the key is present, it
	 * is moved to the first position of the iteration order.
	 *
	 * @param k
	 *            the key.
	 * @return the corresponding value, or the {@linkplain #defaultReturnValue()
	 *         default return value} if no value was present for the given key.
	 */
	public double getAndMoveToFirst(final short k) {
		if (((k) == ((short) 0))) {
			if (containsNullKey) {
				moveIndexToFirst(n);
				return value[n];
			}
			return defRetValue;
		}
		short curr;
		final short[] key = this.key;
		int pos;
		// The starting point.
		if (((curr = key[pos = (it.unimi.dsi.fastutil.HashCommon.mix((k))) & mask]) == ((short) 0)))
			return defRetValue;
		if (((k) == (curr))) {
			moveIndexToFirst(pos);
			return value[pos];
		}
		// There's always an unused entry.
		while (true) {
			if (((curr = key[pos = (pos + 1) & mask]) == ((short) 0)))
				return defRetValue;
			if (((k) == (curr))) {
				moveIndexToFirst(pos);
				return value[pos];
			}
		}
	}
	
Returns the value to which the given key is mapped; if the key is present, it
is moved to the last position of the iteration order.

Params:
  • k – 
           the key.
Returns:the corresponding value, or the 
        default return value if no value was present for the given key.
/**
	 * Returns the value to which the given key is mapped; if the key is present, it
	 * is moved to the last position of the iteration order.
	 *
	 * @param k
	 *            the key.
	 * @return the corresponding value, or the {@linkplain #defaultReturnValue()
	 *         default return value} if no value was present for the given key.
	 */
	public double getAndMoveToLast(final short k) {
		if (((k) == ((short) 0))) {
			if (containsNullKey) {
				moveIndexToLast(n);
				return value[n];
			}
			return defRetValue;
		}
		short curr;
		final short[] key = this.key;
		int pos;
		// The starting point.
		if (((curr = key[pos = (it.unimi.dsi.fastutil.HashCommon.mix((k))) & mask]) == ((short) 0)))
			return defRetValue;
		if (((k) == (curr))) {
			moveIndexToLast(pos);
			return value[pos];
		}
		// There's always an unused entry.
		while (true) {
			if (((curr = key[pos = (pos + 1) & mask]) == ((short) 0)))
				return defRetValue;
			if (((k) == (curr))) {
				moveIndexToLast(pos);
				return value[pos];
			}
		}
	}
	
Adds a pair to the map; if the key is already present, it is moved to the
first position of the iteration order.

Params:
  • k – 
           the key.
  • v – 
           the value.
Returns:the old value, or the default
        return value if no value was present for the given key.
/**
	 * Adds a pair to the map; if the key is already present, it is moved to the
	 * first position of the iteration order.
	 *
	 * @param k
	 *            the key.
	 * @param v
	 *            the value.
	 * @return the old value, or the {@linkplain #defaultReturnValue() default
	 *         return value} if no value was present for the given key.
	 */
	public double putAndMoveToFirst(final short k, final double v) {
		int pos;
		if (((k) == ((short) 0))) {
			if (containsNullKey) {
				moveIndexToFirst(n);
				return setValue(n, v);
			}
			containsNullKey = true;
			pos = n;
		} else {
			short curr;
			final short[] key = this.key;
			// The starting point.
			if (!((curr = key[pos = (it.unimi.dsi.fastutil.HashCommon.mix((k))) & mask]) == ((short) 0))) {
				if (((curr) == (k))) {
					moveIndexToFirst(pos);
					return setValue(pos, v);
				}
				while (!((curr = key[pos = (pos + 1) & mask]) == ((short) 0)))
					if (((curr) == (k))) {
						moveIndexToFirst(pos);
						return setValue(pos, v);
					}
			}
		}
		key[pos] = k;
		value[pos] = v;
		if (size == 0) {
			first = last = pos;
			// Special case of SET_UPPER_LOWER(link[pos], -1, -1);
			link[pos] = -1L;
		} else {
			link[first] ^= ((link[first] ^ ((pos & 0xFFFFFFFFL) << 32)) & 0xFFFFFFFF00000000L);
			link[pos] = ((-1 & 0xFFFFFFFFL) << 32) | (first & 0xFFFFFFFFL);
			first = pos;
		}
		if (size++ >= maxFill)
			rehash(arraySize(size, f));
		if (ASSERTS)
			checkTable();
		return defRetValue;
	}
	
Adds a pair to the map; if the key is already present, it is moved to the
last position of the iteration order.

Params:
  • k – 
           the key.
  • v – 
           the value.
Returns:the old value, or the default
        return value if no value was present for the given key.
/**
	 * Adds a pair to the map; if the key is already present, it is moved to the
	 * last position of the iteration order.
	 *
	 * @param k
	 *            the key.
	 * @param v
	 *            the value.
	 * @return the old value, or the {@linkplain #defaultReturnValue() default
	 *         return value} if no value was present for the given key.
	 */
	public double putAndMoveToLast(final short k, final double v) {
		int pos;
		if (((k) == ((short) 0))) {
			if (containsNullKey) {
				moveIndexToLast(n);
				return setValue(n, v);
			}
			containsNullKey = true;
			pos = n;
		} else {
			short curr;
			final short[] key = this.key;
			// The starting point.
			if (!((curr = key[pos = (it.unimi.dsi.fastutil.HashCommon.mix((k))) & mask]) == ((short) 0))) {
				if (((curr) == (k))) {
					moveIndexToLast(pos);
					return setValue(pos, v);
				}
				while (!((curr = key[pos = (pos + 1) & mask]) == ((short) 0)))
					if (((curr) == (k))) {
						moveIndexToLast(pos);
						return setValue(pos, v);
					}
			}
		}
		key[pos] = k;
		value[pos] = v;
		if (size == 0) {
			first = last = pos;
			// Special case of SET_UPPER_LOWER(link[pos], -1, -1);
			link[pos] = -1L;
		} else {
			link[last] ^= ((link[last] ^ (pos & 0xFFFFFFFFL)) & 0xFFFFFFFFL);
			link[pos] = ((last & 0xFFFFFFFFL) << 32) | (-1 & 0xFFFFFFFFL);
			last = pos;
		}
		if (size++ >= maxFill)
			rehash(arraySize(size, f));
		if (ASSERTS)
			checkTable();
		return defRetValue;
	}
	@Override

	public double get(final short k) {
		if (((k) == ((short) 0)))
			return containsNullKey ? value[n] : defRetValue;
		short curr;
		final short[] key = this.key;
		int pos;
		// The starting point.
		if (((curr = key[pos = (it.unimi.dsi.fastutil.HashCommon.mix((k))) & mask]) == ((short) 0)))
			return defRetValue;
		if (((k) == (curr)))
			return value[pos];
		// There's always an unused entry.
		while (true) {
			if (((curr = key[pos = (pos + 1) & mask]) == ((short) 0)))
				return defRetValue;
			if (((k) == (curr)))
				return value[pos];
		}
	}
	@Override

	public boolean containsKey(final short k) {
		if (((k) == ((short) 0)))
			return containsNullKey;
		short curr;
		final short[] key = this.key;
		int pos;
		// The starting point.
		if (((curr = key[pos = (it.unimi.dsi.fastutil.HashCommon.mix((k))) & mask]) == ((short) 0)))
			return false;
		if (((k) == (curr)))
			return true;
		// There's always an unused entry.
		while (true) {
			if (((curr = key[pos = (pos + 1) & mask]) == ((short) 0)))
				return false;
			if (((k) == (curr)))
				return true;
		}
	}
	@Override
	public boolean containsValue(final double v) {
		final double value[] = this.value;
		final short key[] = this.key;
		if (containsNullKey && (Double.doubleToLongBits(value[n]) == Double.doubleToLongBits(v)))
			return true;
		for (int i = n; i-- != 0;)
			if (!((key[i]) == ((short) 0)) && (Double.doubleToLongBits(value[i]) == Double.doubleToLongBits(v)))
				return true;
		return false;
	}
	
{@inheritDoc} 
/** {@inheritDoc} */
	@Override

	public double getOrDefault(final short k, final double defaultValue) {
		if (((k) == ((short) 0)))
			return containsNullKey ? value[n] : defaultValue;
		short curr;
		final short[] key = this.key;
		int pos;
		// The starting point.
		if (((curr = key[pos = (it.unimi.dsi.fastutil.HashCommon.mix((k))) & mask]) == ((short) 0)))
			return defaultValue;
		if (((k) == (curr)))
			return value[pos];
		// There's always an unused entry.
		while (true) {
			if (((curr = key[pos = (pos + 1) & mask]) == ((short) 0)))
				return defaultValue;
			if (((k) == (curr)))
				return value[pos];
		}
	}
	
{@inheritDoc} 
/** {@inheritDoc} */
	@Override
	public double putIfAbsent(final short k, final double v) {
		final int pos = find(k);
		if (pos >= 0)
			return value[pos];
		insert(-pos - 1, k, v);
		return defRetValue;
	}
	
{@inheritDoc} 
/** {@inheritDoc} */
	@Override

	public boolean remove(final short k, final double v) {
		if (((k) == ((short) 0))) {
			if (containsNullKey && (Double.doubleToLongBits(v) == Double.doubleToLongBits(value[n]))) {
				removeNullEntry();
				return true;
			}
			return false;
		}
		short curr;
		final short[] key = this.key;
		int pos;
		// The starting point.
		if (((curr = key[pos = (it.unimi.dsi.fastutil.HashCommon.mix((k))) & mask]) == ((short) 0)))
			return false;
		if (((k) == (curr)) && (Double.doubleToLongBits(v) == Double.doubleToLongBits(value[pos]))) {
			removeEntry(pos);
			return true;
		}
		while (true) {
			if (((curr = key[pos = (pos + 1) & mask]) == ((short) 0)))
				return false;
			if (((k) == (curr)) && (Double.doubleToLongBits(v) == Double.doubleToLongBits(value[pos]))) {
				removeEntry(pos);
				return true;
			}
		}
	}
	
{@inheritDoc} 
/** {@inheritDoc} */
	@Override
	public boolean replace(final short k, final double oldValue, final double v) {
		final int pos = find(k);
		if (pos < 0 || !(Double.doubleToLongBits(oldValue) == Double.doubleToLongBits(value[pos])))
			return false;
		value[pos] = v;
		return true;
	}
	
{@inheritDoc} 
/** {@inheritDoc} */
	@Override
	public double replace(final short k, final double v) {
		final int pos = find(k);
		if (pos < 0)
			return defRetValue;
		final double oldValue = value[pos];
		value[pos] = v;
		return oldValue;
	}
	
{@inheritDoc} 
/** {@inheritDoc} */
	@Override
	public double computeIfAbsent(final short k, final java.util.function.IntToDoubleFunction mappingFunction) {
		java.util.Objects.requireNonNull(mappingFunction);
		final int pos = find(k);
		if (pos >= 0)
			return value[pos];
		final double newValue = mappingFunction.applyAsDouble(k);
		insert(-pos - 1, k, newValue);
		return newValue;
	}
	
{@inheritDoc} 
/** {@inheritDoc} */
	@Override
	public double computeIfAbsentNullable(final short k,
			final java.util.function.IntFunction<? extends Double> mappingFunction) {
		java.util.Objects.requireNonNull(mappingFunction);
		final int pos = find(k);
		if (pos >= 0)
			return value[pos];
		final Double newValue = mappingFunction.apply(k);
		if (newValue == null)
			return defRetValue;
		final double v = (newValue).doubleValue();
		insert(-pos - 1, k, v);
		return v;
	}
	
{@inheritDoc} 
/** {@inheritDoc} */
	@Override
	public double computeIfPresent(final short k,
			final java.util.function.BiFunction<? super Short, ? super Double, ? extends Double> remappingFunction) {
		java.util.Objects.requireNonNull(remappingFunction);
		final int pos = find(k);
		if (pos < 0)
			return defRetValue;
		final Double newValue = remappingFunction.apply(Short.valueOf(k), Double.valueOf(value[pos]));
		if (newValue == null) {
			if (((k) == ((short) 0)))
				removeNullEntry();
			else
				removeEntry(pos);
			return defRetValue;
		}
		return value[pos] = (newValue).doubleValue();
	}
	
{@inheritDoc} 
/** {@inheritDoc} */
	@Override
	public double compute(final short k,
			final java.util.function.BiFunction<? super Short, ? super Double, ? extends Double> remappingFunction) {
		java.util.Objects.requireNonNull(remappingFunction);
		final int pos = find(k);
		final Double newValue = remappingFunction.apply(Short.valueOf(k), pos >= 0 ? Double.valueOf(value[pos]) : null);
		if (newValue == null) {
			if (pos >= 0) {
				if (((k) == ((short) 0)))
					removeNullEntry();
				else
					removeEntry(pos);
			}
			return defRetValue;
		}
		double newVal = (newValue).doubleValue();
		if (pos < 0) {
			insert(-pos - 1, k, newVal);
			return newVal;
		}
		return value[pos] = newVal;
	}
	
{@inheritDoc} 
/** {@inheritDoc} */
	@Override
	public double merge(final short k, final double v,
			final java.util.function.BiFunction<? super Double, ? super Double, ? extends Double> remappingFunction) {
		java.util.Objects.requireNonNull(remappingFunction);
		final int pos = find(k);
		if (pos < 0) {
			insert(-pos - 1, k, v);
			return v;
		}
		final Double newValue = remappingFunction.apply(Double.valueOf(value[pos]), Double.valueOf(v));
		if (newValue == null) {
			if (((k) == ((short) 0)))
				removeNullEntry();
			else
				removeEntry(pos);
			return defRetValue;
		}
		return value[pos] = (newValue).doubleValue();
	}
	/*
	 * Removes all elements from this map.
	 *
	 * <p>To increase object reuse, this method does not change the table size. If
	 * you want to reduce the table size, you must use {@link #trim()}.
	 *
	 */
	@Override
	public void clear() {
		if (size == 0)
			return;
		size = 0;
		containsNullKey = false;
		Arrays.fill(key, ((short) 0));
		first = last = -1;
	}
	@Override
	public int size() {
		return size;
	}
	@Override
	public boolean isEmpty() {
		return size == 0;
	}
	
The entry class for a hash map does not record key and value, but rather the position in the hash table of the corresponding entry. This is necessary so that calls to Entry.setValue(Object) are reflected in the map 
/**
	 * The entry class for a hash map does not record key and value, but rather the
	 * position in the hash table of the corresponding entry. This is necessary so
	 * that calls to {@link java.util.Map.Entry#setValue(Object)} are reflected in
	 * the map
	 */
	final class MapEntry implements Short2DoubleMap.Entry, Map.Entry<Short, Double> {
		// The table index this entry refers to, or -1 if this entry has been deleted.
		int index;
		MapEntry(final int index) {
			this.index = index;
		}
		MapEntry() {
		}
		@Override
		public short getShortKey() {
			return key[index];
		}
		@Override
		public double getDoubleValue() {
			return value[index];
		}
		@Override
		public double setValue(final double v) {
			final double oldValue = value[index];
			value[index] = v;
			return oldValue;
		}
		
{@inheritDoc}

Deprecated:Please use the corresponding type-specific method instead.
/**
		 * {@inheritDoc}
		 * 
		 * @deprecated Please use the corresponding type-specific method instead.
		 */
		@Deprecated
		@Override
		public Short getKey() {
			return Short.valueOf(key[index]);
		}
		
{@inheritDoc}

Deprecated:Please use the corresponding type-specific method instead.
/**
		 * {@inheritDoc}
		 * 
		 * @deprecated Please use the corresponding type-specific method instead.
		 */
		@Deprecated
		@Override
		public Double getValue() {
			return Double.valueOf(value[index]);
		}
		
{@inheritDoc}

Deprecated:Please use the corresponding type-specific method instead.
/**
		 * {@inheritDoc}
		 * 
		 * @deprecated Please use the corresponding type-specific method instead.
		 */
		@Deprecated
		@Override
		public Double setValue(final Double v) {
			return Double.valueOf(setValue((v).doubleValue()));
		}
		@SuppressWarnings("unchecked")
		@Override
		public boolean equals(final Object o) {
			if (!(o instanceof Map.Entry))
				return false;
			Map.Entry<Short, Double> e = (Map.Entry<Short, Double>) o;
			return ((key[index]) == ((e.getKey()).shortValue()))
					&& (Double.doubleToLongBits(value[index]) == Double.doubleToLongBits((e.getValue()).doubleValue()));
		}
		@Override
		public int hashCode() {
			return (key[index]) ^ it.unimi.dsi.fastutil.HashCommon.double2int(value[index]);
		}
		@Override
		public String toString() {
			return key[index] + "=>" + value[index];
		}
	}
	
Modifies the link vector so that the given entry is removed. This method will complete in constant time. 
Params:
  • i – 
           the index of an entry.
/**
	 * Modifies the {@link #link} vector so that the given entry is removed. This
	 * method will complete in constant time.
	 *
	 * @param i
	 *            the index of an entry.
	 */
	protected void fixPointers(final int i) {
		if (size == 0) {
			first = last = -1;
			return;
		}
		if (first == i) {
			first = (int) link[i];
			if (0 <= first) {
				// Special case of SET_PREV(link[first], -1)
				link[first] |= (-1 & 0xFFFFFFFFL) << 32;
			}
			return;
		}
		if (last == i) {
			last = (int) (link[i] >>> 32);
			if (0 <= last) {
				// Special case of SET_NEXT(link[last], -1)
				link[last] |= -1 & 0xFFFFFFFFL;
			}
			return;
		}
		final long linki = link[i];
		final int prev = (int) (linki >>> 32);
		final int next = (int) linki;
		link[prev] ^= ((link[prev] ^ (linki & 0xFFFFFFFFL)) & 0xFFFFFFFFL);
		link[next] ^= ((link[next] ^ (linki & 0xFFFFFFFF00000000L)) & 0xFFFFFFFF00000000L);
	}
	
Modifies the link vector for a shift from s to d. 

This method will complete in constant time.

Params:
  • s – 
           the source position.
  • d – 
           the destination position.
/**
	 * Modifies the {@link #link} vector for a shift from s to d.
	 * <p>
	 * This method will complete in constant time.
	 *
	 * @param s
	 *            the source position.
	 * @param d
	 *            the destination position.
	 */
	protected void fixPointers(int s, int d) {
		if (size == 1) {
			first = last = d;
			// Special case of SET_UPPER_LOWER(link[d], -1, -1)
			link[d] = -1L;
			return;
		}
		if (first == s) {
			first = d;
			link[(int) link[s]] ^= ((link[(int) link[s]] ^ ((d & 0xFFFFFFFFL) << 32)) & 0xFFFFFFFF00000000L);
			link[d] = link[s];
			return;
		}
		if (last == s) {
			last = d;
			link[(int) (link[s] >>> 32)] ^= ((link[(int) (link[s] >>> 32)] ^ (d & 0xFFFFFFFFL)) & 0xFFFFFFFFL);
			link[d] = link[s];
			return;
		}
		final long links = link[s];
		final int prev = (int) (links >>> 32);
		final int next = (int) links;
		link[prev] ^= ((link[prev] ^ (d & 0xFFFFFFFFL)) & 0xFFFFFFFFL);
		link[next] ^= ((link[next] ^ ((d & 0xFFFFFFFFL) << 32)) & 0xFFFFFFFF00000000L);
		link[d] = links;
	}
	
Returns the first key of this map in iteration order.

Returns:the first key in iteration order.
/**
	 * Returns the first key of this map in iteration order.
	 *
	 * @return the first key in iteration order.
	 */
	@Override
	public short firstShortKey() {
		if (size == 0)
			throw new NoSuchElementException();
		return key[first];
	}
	
Returns the last key of this map in iteration order.

Returns:the last key in iteration order.
/**
	 * Returns the last key of this map in iteration order.
	 *
	 * @return the last key in iteration order.
	 */
	@Override
	public short lastShortKey() {
		if (size == 0)
			throw new NoSuchElementException();
		return key[last];
	}
	
{@inheritDoc}

 This implementation just throws an UnsupportedOperationException. 
/**
	 * {@inheritDoc}
	 * <p>
	 * This implementation just throws an {@link UnsupportedOperationException}.
	 */
	@Override
	public Short2DoubleSortedMap tailMap(short from) {
		throw new UnsupportedOperationException();
	}
	
{@inheritDoc}

 This implementation just throws an UnsupportedOperationException. 
/**
	 * {@inheritDoc}
	 * <p>
	 * This implementation just throws an {@link UnsupportedOperationException}.
	 */
	@Override
	public Short2DoubleSortedMap headMap(short to) {
		throw new UnsupportedOperationException();
	}
	
{@inheritDoc}

 This implementation just throws an UnsupportedOperationException. 
/**
	 * {@inheritDoc}
	 * <p>
	 * This implementation just throws an {@link UnsupportedOperationException}.
	 */
	@Override
	public Short2DoubleSortedMap subMap(short from, short to) {
		throw new UnsupportedOperationException();
	}
	
{@inheritDoc}

 This implementation just returns null. 
/**
	 * {@inheritDoc}
	 * <p>
	 * This implementation just returns {@code null}.
	 */
	@Override
	public ShortComparator comparator() {
		return null;
	}
	
A list iterator over a linked map.


This class provides a list iterator over a linked hash map. The constructor
runs in constant time.

/**
	 * A list iterator over a linked map.
	 *
	 * <p>
	 * This class provides a list iterator over a linked hash map. The constructor
	 * runs in constant time.
	 */
	private class MapIterator {
		
The entry that will be returned by the next call to ListIterator.previous() (or null if no previous entry exists). 
/**
		 * The entry that will be returned by the next call to
		 * {@link java.util.ListIterator#previous()} (or {@code null} if no previous
		 * entry exists).
		 */
		int prev = -1;
		
The entry that will be returned by the next call to ListIterator.next() (or null if no next entry exists). 
/**
		 * The entry that will be returned by the next call to
		 * {@link java.util.ListIterator#next()} (or {@code null} if no next entry
		 * exists).
		 */
		int next = -1;
		
The last entry that was returned (or -1 if we did not iterate or used Iterator.remove()). 
/**
		 * The last entry that was returned (or -1 if we did not iterate or used
		 * {@link java.util.Iterator#remove()}).
		 */
		int curr = -1;
		
The current index (in the sense of a ListIterator). Note that this value is not meaningful when this iterator has been created using the nonempty constructor. 
/**
		 * The current index (in the sense of a {@link java.util.ListIterator}). Note
		 * that this value is not meaningful when this iterator has been created using
		 * the nonempty constructor.
		 */
		int index = -1;
		protected MapIterator() {
			next = first;
			index = 0;
		}
		private MapIterator(final short from) {
			if (((from) == ((short) 0))) {
				if (Short2DoubleLinkedOpenHashMap.this.containsNullKey) {
					next = (int) link[n];
					prev = n;
					return;
				} else
					throw new NoSuchElementException("The key " + from + " does not belong to this map.");
			}
			if (((key[last]) == (from))) {
				prev = last;
				index = size;
				return;
			}
			// The starting point.
			int pos = (it.unimi.dsi.fastutil.HashCommon.mix((from))) & mask;
			// There's always an unused entry.
			while (!((key[pos]) == ((short) 0))) {
				if (((key[pos]) == (from))) {
					// Note: no valid index known.
					next = (int) link[pos];
					prev = pos;
					return;
				}
				pos = (pos + 1) & mask;
			}
			throw new NoSuchElementException("The key " + from + " does not belong to this map.");
		}
		public boolean hasNext() {
			return next != -1;
		}
		public boolean hasPrevious() {
			return prev != -1;
		}
		private final void ensureIndexKnown() {
			if (index >= 0)
				return;
			if (prev == -1) {
				index = 0;
				return;
			}
			if (next == -1) {
				index = size;
				return;
			}
			int pos = first;
			index = 1;
			while (pos != prev) {
				pos = (int) link[pos];
				index++;
			}
		}
		public int nextIndex() {
			ensureIndexKnown();
			return index;
		}
		public int previousIndex() {
			ensureIndexKnown();
			return index - 1;
		}
		public int nextEntry() {
			if (!hasNext())
				throw new NoSuchElementException();
			curr = next;
			next = (int) link[curr];
			prev = curr;
			if (index >= 0)
				index++;
			return curr;
		}
		public int previousEntry() {
			if (!hasPrevious())
				throw new NoSuchElementException();
			curr = prev;
			prev = (int) (link[curr] >>> 32);
			next = curr;
			if (index >= 0)
				index--;
			return curr;
		}
		public void remove() {
			ensureIndexKnown();
			if (curr == -1)
				throw new IllegalStateException();
			if (curr == prev) {
				/*
				 * If the last operation was a next(), we are removing an entry that preceeds
				 * the current index, and thus we must decrement it.
				 */
				index--;
				prev = (int) (link[curr] >>> 32);
			} else
				next = (int) link[curr];
			size--;
			/*
			 * Now we manually fix the pointers. Because of our knowledge of next and prev,
			 * this is going to be faster than calling fixPointers().
			 */
			if (prev == -1)
				first = next;
			else
				link[prev] ^= ((link[prev] ^ (next & 0xFFFFFFFFL)) & 0xFFFFFFFFL);
			if (next == -1)
				last = prev;
			else
				link[next] ^= ((link[next] ^ ((prev & 0xFFFFFFFFL) << 32)) & 0xFFFFFFFF00000000L);
			int last, slot, pos = curr;
			curr = -1;
			if (pos == n) {
				Short2DoubleLinkedOpenHashMap.this.containsNullKey = false;
			} else {
				short curr;
				final short[] key = Short2DoubleLinkedOpenHashMap.this.key;
				// We have to horribly duplicate the shiftKeys() code because we need to update
				// next/prev.
				for (;;) {
					pos = ((last = pos) + 1) & mask;
					for (;;) {
						if (((curr = key[pos]) == ((short) 0))) {
							key[last] = ((short) 0);
							return;
						}
						slot = (it.unimi.dsi.fastutil.HashCommon.mix((curr))) & mask;
						if (last <= pos ? last >= slot || slot > pos : last >= slot && slot > pos)
							break;
						pos = (pos + 1) & mask;
					}
					key[last] = curr;
					value[last] = value[pos];
					if (next == pos)
						next = last;
					if (prev == pos)
						prev = last;
					fixPointers(pos, last);
				}
			}
		}
		public int skip(final int n) {
			int i = n;
			while (i-- != 0 && hasNext())
				nextEntry();
			return n - i - 1;
		}
		public int back(final int n) {
			int i = n;
			while (i-- != 0 && hasPrevious())
				previousEntry();
			return n - i - 1;
		}
		public void set(@SuppressWarnings("unused") Short2DoubleMap.Entry ok) {
			throw new UnsupportedOperationException();
		}
		public void add(@SuppressWarnings("unused") Short2DoubleMap.Entry ok) {
			throw new UnsupportedOperationException();
		}
	}
	private class EntryIterator extends MapIterator implements ObjectListIterator<Short2DoubleMap.Entry> {
		private MapEntry entry;
		public EntryIterator() {
		}
		public EntryIterator(short from) {
			super(from);
		}
		@Override
		public MapEntry next() {
			return entry = new MapEntry(nextEntry());
		}
		@Override
		public MapEntry previous() {
			return entry = new MapEntry(previousEntry());
		}
		@Override
		public void remove() {
			super.remove();
			entry.index = -1; // You cannot use a deleted entry.
		}
	}
	private class FastEntryIterator extends MapIterator implements ObjectListIterator<Short2DoubleMap.Entry> {
		final MapEntry entry = new MapEntry();
		public FastEntryIterator() {
		}
		public FastEntryIterator(short from) {
			super(from);
		}
		@Override
		public MapEntry next() {
			entry.index = nextEntry();
			return entry;
		}
		@Override
		public MapEntry previous() {
			entry.index = previousEntry();
			return entry;
		}
	}
	private final class MapEntrySet extends AbstractObjectSortedSet<Short2DoubleMap.Entry>
			implements
				FastSortedEntrySet {
		@Override
		public ObjectBidirectionalIterator<Short2DoubleMap.Entry> iterator() {
			return new EntryIterator();
		}
		@Override
		public Comparator<? super Short2DoubleMap.Entry> comparator() {
			return null;
		}
		@Override
		public ObjectSortedSet<Short2DoubleMap.Entry> subSet(Short2DoubleMap.Entry fromElement,
				Short2DoubleMap.Entry toElement) {
			throw new UnsupportedOperationException();
		}
		@Override
		public ObjectSortedSet<Short2DoubleMap.Entry> headSet(Short2DoubleMap.Entry toElement) {
			throw new UnsupportedOperationException();
		}
		@Override
		public ObjectSortedSet<Short2DoubleMap.Entry> tailSet(Short2DoubleMap.Entry fromElement) {
			throw new UnsupportedOperationException();
		}
		@Override
		public Short2DoubleMap.Entry first() {
			if (size == 0)
				throw new NoSuchElementException();
			return new MapEntry(Short2DoubleLinkedOpenHashMap.this.first);
		}
		@Override
		public Short2DoubleMap.Entry last() {
			if (size == 0)
				throw new NoSuchElementException();
			return new MapEntry(Short2DoubleLinkedOpenHashMap.this.last);
		}
		@Override

		public boolean contains(final Object o) {
			if (!(o instanceof Map.Entry))
				return false;
			final Map.Entry<?, ?> e = (Map.Entry<?, ?>) o;
			if (e.getKey() == null || !(e.getKey() instanceof Short))
				return false;
			if (e.getValue() == null || !(e.getValue() instanceof Double))
				return false;
			final short k = ((Short) (e.getKey())).shortValue();
			final double v = ((Double) (e.getValue())).doubleValue();
			if (((k) == ((short) 0)))
				return Short2DoubleLinkedOpenHashMap.this.containsNullKey
						&& (Double.doubleToLongBits(value[n]) == Double.doubleToLongBits(v));
			short curr;
			final short[] key = Short2DoubleLinkedOpenHashMap.this.key;
			int pos;
			// The starting point.
			if (((curr = key[pos = (it.unimi.dsi.fastutil.HashCommon.mix((k))) & mask]) == ((short) 0)))
				return false;
			if (((k) == (curr)))
				return (Double.doubleToLongBits(value[pos]) == Double.doubleToLongBits(v));
			// There's always an unused entry.
			while (true) {
				if (((curr = key[pos = (pos + 1) & mask]) == ((short) 0)))
					return false;
				if (((k) == (curr)))
					return (Double.doubleToLongBits(value[pos]) == Double.doubleToLongBits(v));
			}
		}
		@Override

		public boolean remove(final Object o) {
			if (!(o instanceof Map.Entry))
				return false;
			final Map.Entry<?, ?> e = (Map.Entry<?, ?>) o;
			if (e.getKey() == null || !(e.getKey() instanceof Short))
				return false;
			if (e.getValue() == null || !(e.getValue() instanceof Double))
				return false;
			final short k = ((Short) (e.getKey())).shortValue();
			final double v = ((Double) (e.getValue())).doubleValue();
			if (((k) == ((short) 0))) {
				if (containsNullKey && (Double.doubleToLongBits(value[n]) == Double.doubleToLongBits(v))) {
					removeNullEntry();
					return true;
				}
				return false;
			}
			short curr;
			final short[] key = Short2DoubleLinkedOpenHashMap.this.key;
			int pos;
			// The starting point.
			if (((curr = key[pos = (it.unimi.dsi.fastutil.HashCommon.mix((k))) & mask]) == ((short) 0)))
				return false;
			if (((curr) == (k))) {
				if ((Double.doubleToLongBits(value[pos]) == Double.doubleToLongBits(v))) {
					removeEntry(pos);
					return true;
				}
				return false;
			}
			while (true) {
				if (((curr = key[pos = (pos + 1) & mask]) == ((short) 0)))
					return false;
				if (((curr) == (k))) {
					if ((Double.doubleToLongBits(value[pos]) == Double.doubleToLongBits(v))) {
						removeEntry(pos);
						return true;
					}
				}
			}
		}
		@Override
		public int size() {
			return size;
		}
		@Override
		public void clear() {
			Short2DoubleLinkedOpenHashMap.this.clear();
		}
		
Returns a type-specific list iterator on the elements in this set, starting
from a given element of the set. Please see the class documentation for
implementation details.

Params:
  • from – 
           an element to start from.
Throws:
Returns:a type-specific list iterator starting at the given element.
/**
		 * Returns a type-specific list iterator on the elements in this set, starting
		 * from a given element of the set. Please see the class documentation for
		 * implementation details.
		 *
		 * @param from
		 *            an element to start from.
		 * @return a type-specific list iterator starting at the given element.
		 * @throws IllegalArgumentException
		 *             if {@code from} does not belong to the set.
		 */
		@Override
		public ObjectListIterator<Short2DoubleMap.Entry> iterator(final Short2DoubleMap.Entry from) {
			return new EntryIterator(from.getShortKey());
		}
		
Returns a type-specific fast list iterator on the elements in this set,
starting from the first element. Please see the class documentation for
implementation details.

Returns:a type-specific list iterator starting at the first element.
/**
		 * Returns a type-specific fast list iterator on the elements in this set,
		 * starting from the first element. Please see the class documentation for
		 * implementation details.
		 *
		 * @return a type-specific list iterator starting at the first element.
		 */
		@Override
		public ObjectListIterator<Short2DoubleMap.Entry> fastIterator() {
			return new FastEntryIterator();
		}
		
Returns a type-specific fast list iterator on the elements in this set,
starting from a given element of the set. Please see the class documentation
for implementation details.

Params:
  • from – 
           an element to start from.
Throws:
Returns:a type-specific list iterator starting at the given element.
/**
		 * Returns a type-specific fast list iterator on the elements in this set,
		 * starting from a given element of the set. Please see the class documentation
		 * for implementation details.
		 *
		 * @param from
		 *            an element to start from.
		 * @return a type-specific list iterator starting at the given element.
		 * @throws IllegalArgumentException
		 *             if {@code from} does not belong to the set.
		 */
		@Override
		public ObjectListIterator<Short2DoubleMap.Entry> fastIterator(final Short2DoubleMap.Entry from) {
			return new FastEntryIterator(from.getShortKey());
		}
		
{@inheritDoc} 
/** {@inheritDoc} */
		@Override
		public void forEach(final Consumer<? super Short2DoubleMap.Entry> consumer) {
			for (int i = size, curr, next = first; i-- != 0;) {
				curr = next;
				next = (int) link[curr];
				consumer.accept(new AbstractShort2DoubleMap.BasicEntry(key[curr], value[curr]));
			}
		}
		
{@inheritDoc} 
/** {@inheritDoc} */
		@Override
		public void fastForEach(final Consumer<? super Short2DoubleMap.Entry> consumer) {
			final AbstractShort2DoubleMap.BasicEntry entry = new AbstractShort2DoubleMap.BasicEntry();
			for (int i = size, curr, next = first; i-- != 0;) {
				curr = next;
				next = (int) link[curr];
				entry.key = key[curr];
				entry.value = value[curr];
				consumer.accept(entry);
			}
		}
	}
	@Override
	public FastSortedEntrySet short2DoubleEntrySet() {
		if (entries == null)
			entries = new MapEntrySet();
		return entries;
	}
	
An iterator on keys.

 We simply override the ListIterator.next()/ListIterator.previous() methods (and possibly their type-specific counterparts) so that they return keys instead of entries. 
/**
	 * An iterator on keys.
	 *
	 * <p>
	 * We simply override the
	 * {@link java.util.ListIterator#next()}/{@link java.util.ListIterator#previous()}
	 * methods (and possibly their type-specific counterparts) so that they return
	 * keys instead of entries.
	 */
	private final class KeyIterator extends MapIterator implements ShortListIterator {
		public KeyIterator(final short k) {
			super(k);
		}
		@Override
		public short previousShort() {
			return key[previousEntry()];
		}
		public KeyIterator() {
			super();
		}
		@Override
		public short nextShort() {
			return key[nextEntry()];
		}
	}
	private final class KeySet extends AbstractShortSortedSet {
		@Override
		public ShortListIterator iterator(final short from) {
			return new KeyIterator(from);
		}
		@Override
		public ShortListIterator iterator() {
			return new KeyIterator();
		}
		
{@inheritDoc} 
/** {@inheritDoc} */
		@Override
		public void forEach(final java.util.function.IntConsumer consumer) {
			if (containsNullKey)
				consumer.accept(key[n]);
			for (int pos = n; pos-- != 0;) {
				final short k = key[pos];
				if (!((k) == ((short) 0)))
					consumer.accept(k);
			}
		}
		@Override
		public int size() {
			return size;
		}
		@Override
		public boolean contains(short k) {
			return containsKey(k);
		}
		@Override
		public boolean remove(short k) {
			final int oldSize = size;
			Short2DoubleLinkedOpenHashMap.this.remove(k);
			return size != oldSize;
		}
		@Override
		public void clear() {
			Short2DoubleLinkedOpenHashMap.this.clear();
		}
		@Override
		public short firstShort() {
			if (size == 0)
				throw new NoSuchElementException();
			return key[first];
		}
		@Override
		public short lastShort() {
			if (size == 0)
				throw new NoSuchElementException();
			return key[last];
		}
		@Override
		public ShortComparator comparator() {
			return null;
		}
		@Override
		public ShortSortedSet tailSet(short from) {
			throw new UnsupportedOperationException();
		}
		@Override
		public ShortSortedSet headSet(short to) {
			throw new UnsupportedOperationException();
		}
		@Override
		public ShortSortedSet subSet(short from, short to) {
			throw new UnsupportedOperationException();
		}
	}
	@Override
	public ShortSortedSet keySet() {
		if (keys == null)
			keys = new KeySet();
		return keys;
	}
	
An iterator on values.

 We simply override the ListIterator.next()/ListIterator.previous() methods (and possibly their type-specific counterparts) so that they return values instead of entries. 
/**
	 * An iterator on values.
	 *
	 * <p>
	 * We simply override the
	 * {@link java.util.ListIterator#next()}/{@link java.util.ListIterator#previous()}
	 * methods (and possibly their type-specific counterparts) so that they return
	 * values instead of entries.
	 */
	private final class ValueIterator extends MapIterator implements DoubleListIterator {
		@Override
		public double previousDouble() {
			return value[previousEntry()];
		}
		public ValueIterator() {
			super();
		}
		@Override
		public double nextDouble() {
			return value[nextEntry()];
		}
	}
	@Override
	public DoubleCollection values() {
		if (values == null)
			values = new AbstractDoubleCollection() {
				@Override
				public DoubleIterator iterator() {
					return new ValueIterator();
				}
				@Override
				public int size() {
					return size;
				}
				@Override
				public boolean contains(double v) {
					return containsValue(v);
				}
				@Override
				public void clear() {
					Short2DoubleLinkedOpenHashMap.this.clear();
				}
				
{@inheritDoc} 
/** {@inheritDoc} */
				@Override
				public void forEach(final java.util.function.DoubleConsumer consumer) {
					if (containsNullKey)
						consumer.accept(value[n]);
					for (int pos = n; pos-- != 0;)
						if (!((key[pos]) == ((short) 0)))
							consumer.accept(value[pos]);
				}
			};
		return values;
	}
	
Rehashes the map, making the table as small as possible.


This method rehashes the table to the smallest size satisfying the load
factor. It can be used when the set will not be changed anymore, so to
optimize access speed and size.


If the table size is already the minimum possible, this method does nothing.

See Also:
Returns:true if there was enough memory to trim the map.
/**
	 * Rehashes the map, making the table as small as possible.
	 *
	 * <p>
	 * This method rehashes the table to the smallest size satisfying the load
	 * factor. It can be used when the set will not be changed anymore, so to
	 * optimize access speed and size.
	 *
	 * <p>
	 * If the table size is already the minimum possible, this method does nothing.
	 *
	 * @return true if there was enough memory to trim the map.
	 * @see #trim(int)
	 */
	public boolean trim() {
		return trim(size);
	}
	
Rehashes this map if the table is too large.


Let N be the smallest table size that can hold
max(n,size()) entries, still satisfying the load
factor. If the current table size is smaller than or equal to N,
this method does nothing. Otherwise, it rehashes this map in a table of size
N.

 This method is useful when reusing maps. Clearing a map leaves the table size untouched. If you are reusing a map many times, you can call this method with a typical size to avoid keeping around a very large table just because of a few large transient maps. 
Params:
  • n – 
           the threshold for the trimming.
See Also:
Returns:true if there was enough memory to trim the map.
/**
	 * Rehashes this map if the table is too large.
	 *
	 * <p>
	 * Let <var>N</var> be the smallest table size that can hold
	 * <code>max(n,{@link #size()})</code> entries, still satisfying the load
	 * factor. If the current table size is smaller than or equal to <var>N</var>,
	 * this method does nothing. Otherwise, it rehashes this map in a table of size
	 * <var>N</var>.
	 *
	 * <p>
	 * This method is useful when reusing maps. {@linkplain #clear() Clearing a map}
	 * leaves the table size untouched. If you are reusing a map many times, you can
	 * call this method with a typical size to avoid keeping around a very large
	 * table just because of a few large transient maps.
	 *
	 * @param n
	 *            the threshold for the trimming.
	 * @return true if there was enough memory to trim the map.
	 * @see #trim()
	 */
	public boolean trim(final int n) {
		final int l = HashCommon.nextPowerOfTwo((int) Math.ceil(n / f));
		if (l >= this.n || size > maxFill(l, f))
			return true;
		try {
			rehash(l);
		} catch (OutOfMemoryError cantDoIt) {
			return false;
		}
		return true;
	}
	
Rehashes the map.


This method implements the basic rehashing strategy, and may be overridden by
subclasses implementing different rehashing strategies (e.g., disk-based
rehashing). However, you should not override this method unless you
understand the internal workings of this class.

Params:
  • newN – 
           the new size
/**
	 * Rehashes the map.
	 *
	 * <p>
	 * This method implements the basic rehashing strategy, and may be overridden by
	 * subclasses implementing different rehashing strategies (e.g., disk-based
	 * rehashing). However, you should not override this method unless you
	 * understand the internal workings of this class.
	 *
	 * @param newN
	 *            the new size
	 */

	protected void rehash(final int newN) {
		final short key[] = this.key;
		final double value[] = this.value;
		final int mask = newN - 1; // Note that this is used by the hashing macro
		final short newKey[] = new short[newN + 1];
		final double newValue[] = new double[newN + 1];
		int i = first, prev = -1, newPrev = -1, t, pos;
		final long link[] = this.link;
		final long newLink[] = new long[newN + 1];
		first = -1;
		for (int j = size; j-- != 0;) {
			if (((key[i]) == ((short) 0)))
				pos = newN;
			else {
				pos = (it.unimi.dsi.fastutil.HashCommon.mix((key[i]))) & mask;
				while (!((newKey[pos]) == ((short) 0)))
					pos = (pos + 1) & mask;
			}
			newKey[pos] = key[i];
			newValue[pos] = value[i];
			if (prev != -1) {
				newLink[newPrev] ^= ((newLink[newPrev] ^ (pos & 0xFFFFFFFFL)) & 0xFFFFFFFFL);
				newLink[pos] ^= ((newLink[pos] ^ ((newPrev & 0xFFFFFFFFL) << 32)) & 0xFFFFFFFF00000000L);
				newPrev = pos;
			} else {
				newPrev = first = pos;
				// Special case of SET(newLink[pos], -1, -1);
				newLink[pos] = -1L;
			}
			t = i;
			i = (int) link[i];
			prev = t;
		}
		this.link = newLink;
		this.last = newPrev;
		if (newPrev != -1)
			// Special case of SET_NEXT(newLink[newPrev], -1);
			newLink[newPrev] |= -1 & 0xFFFFFFFFL;
		n = newN;
		this.mask = mask;
		maxFill = maxFill(n, f);
		this.key = newKey;
		this.value = newValue;
	}
	
Returns a deep copy of this map.


This method performs a deep copy of this hash map; the data stored in the
map, however, is not cloned. Note that this makes a difference only for
object keys.

Returns:a deep copy of this map.
/**
	 * Returns a deep copy of this map.
	 *
	 * <p>
	 * This method performs a deep copy of this hash map; the data stored in the
	 * map, however, is not cloned. Note that this makes a difference only for
	 * object keys.
	 *
	 * @return a deep copy of this map.
	 */
	@Override

	public Short2DoubleLinkedOpenHashMap clone() {
		Short2DoubleLinkedOpenHashMap c;
		try {
			c = (Short2DoubleLinkedOpenHashMap) super.clone();
		} catch (CloneNotSupportedException cantHappen) {
			throw new InternalError();
		}
		c.keys = null;
		c.values = null;
		c.entries = null;
		c.containsNullKey = containsNullKey;
		c.key = key.clone();
		c.value = value.clone();
		c.link = link.clone();
		return c;
	}
	
Returns a hash code for this map. This method overrides the generic method provided by the superclass. Since equals() is not overriden, it is important that the value returned by this method is the same value as the one returned by the overriden method. 
Returns:a hash code for this map.
/**
	 * Returns a hash code for this map.
	 *
	 * This method overrides the generic method provided by the superclass. Since
	 * {@code equals()} is not overriden, it is important that the value returned by
	 * this method is the same value as the one returned by the overriden method.
	 *
	 * @return a hash code for this map.
	 */
	@Override
	public int hashCode() {
		int h = 0;
		for (int j = realSize(), i = 0, t = 0; j-- != 0;) {
			while (((key[i]) == ((short) 0)))
				i++;
			t = (key[i]);
			t ^= it.unimi.dsi.fastutil.HashCommon.double2int(value[i]);
			h += t;
			i++;
		}
		// Zero / null keys have hash zero.
		if (containsNullKey)
			h += it.unimi.dsi.fastutil.HashCommon.double2int(value[n]);
		return h;
	}
	private void writeObject(java.io.ObjectOutputStream s) throws java.io.IOException {
		final short key[] = this.key;
		final double value[] = this.value;
		final MapIterator i = new MapIterator();
		s.defaultWriteObject();
		for (int j = size, e; j-- != 0;) {
			e = i.nextEntry();
			s.writeShort(key[e]);
			s.writeDouble(value[e]);
		}
	}

	private void readObject(java.io.ObjectInputStream s) throws java.io.IOException, ClassNotFoundException {
		s.defaultReadObject();
		n = arraySize(size, f);
		maxFill = maxFill(n, f);
		mask = n - 1;
		final short key[] = this.key = new short[n + 1];
		final double value[] = this.value = new double[n + 1];
		final long link[] = this.link = new long[n + 1];
		int prev = -1;
		first = last = -1;
		short k;
		double v;
		for (int i = size, pos; i-- != 0;) {
			k = s.readShort();
			v = s.readDouble();
			if (((k) == ((short) 0))) {
				pos = n;
				containsNullKey = true;
			} else {
				pos = (it.unimi.dsi.fastutil.HashCommon.mix((k))) & mask;
				while (!((key[pos]) == ((short) 0)))
					pos = (pos + 1) & mask;
			}
			key[pos] = k;
			value[pos] = v;
			if (first != -1) {
				link[prev] ^= ((link[prev] ^ (pos & 0xFFFFFFFFL)) & 0xFFFFFFFFL);
				link[pos] ^= ((link[pos] ^ ((prev & 0xFFFFFFFFL) << 32)) & 0xFFFFFFFF00000000L);
				prev = pos;
			} else {
				prev = first = pos;
				// Special case of SET_PREV(newLink[pos], -1);
				link[pos] |= (-1L & 0xFFFFFFFFL) << 32;
			}
		}
		last = prev;
		if (prev != -1)
			// Special case of SET_NEXT(link[prev], -1);
			link[prev] |= -1 & 0xFFFFFFFFL;
		if (ASSERTS)
			checkTable();
	}
	private void checkTable() {
	}
}