/*
 * Copyright (C) 2002-2017 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 PACKAGE;

import it.unimi.dsi.fastutil.BigArrays;
import it.unimi.dsi.fastutil.Hash;
import it.unimi.dsi.fastutil.Size64;
import it.unimi.dsi.fastutil.HashCommon;
import static it.unimi.dsi.fastutil.HashCommon.bigArraySize;
import static it.unimi.dsi.fastutil.HashCommon.maxFill;

import java.util.Collection;
import java.util.Iterator;
import java.util.NoSuchElementException;


/**  A type-specific hash big set with with a fast, small-footprint implementation.
 *
 * <p>Instances of this class use a hash table to represent a big set: the number
 * of elements in the set is limited only by the amount of core memory. The table
 * (backed by a {@linkplain it.unimi.dsi.fastutil.BigArrays big array}) 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 sets 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>The methods of this class are about 30% slower than those of the corresponding non-big set.
 *
 * @see Hash
 * @see HashCommon
 */

public class OPEN_HASH_BIG_SET KEY_GENERIC extends ABSTRACT_SET KEY_GENERIC implements java.io.Serializable, Cloneable, Hash, Size64 {

	private static final long serialVersionUID = 0L;
	private static final boolean ASSERTS = ASSERTS_VALUE;

	/** The big array of keys. */
	protected transient KEY_GENERIC_TYPE[][] key;

	/** The mask for wrapping a position counter. */
	protected transient long mask;

	/** The mask for wrapping a segment counter. */
	protected transient int segmentMask;

	/** The mask for wrapping a base counter. */
	protected transient int baseMask;

	/** Whether this set contains the null key. */
	protected transient boolean containsNull;

	/** The current table size (always a power of 2). */
	protected transient long n;

	/** Threshold after which we rehash. It must be the table size times {@link #f}. */
	protected transient long maxFill;

	/** We never resize below this threshold, which is the construction-time {#n}. */
	protected final transient long minN;

	/** The acceptable load factor. */
	protected final float f;

	/** Number of entries in the set. */
	protected long size;


	/** Initialises the mask values. */
	private void initMasks() {
		mask = n - 1;
		/* Note that either we have more than one segment, and in this case all segments
		 * are BigArrays.SEGMENT_SIZE long, or we have exactly one segment whose length
		 * is a power of two. */
		segmentMask = key[0].length - 1;
		baseMask = key.length - 1;
	}

	/** Creates a new hash big set.
	 *
	 * <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 set.
	 * @param f the load factor.
	 */
	SUPPRESS_WARNINGS_KEY_UNCHECKED
	public OPEN_HASH_BIG_SET(final long 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 (n < 0) throw new IllegalArgumentException("The expected number of elements must be nonnegative");

		this.f = f;

		minN = n = bigArraySize(expected, f);
		maxFill = maxFill(n, f);
		key = KEY_GENERIC_BIG_ARRAY_CAST BIG_ARRAYS.newBigArray(n);
		initMasks();
	}


	/** Creates a new hash big set with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor.
	 *
	 * @param expected the expected number of elements in the hash big set.
	 */

	public OPEN_HASH_BIG_SET(final long expected) {
		this(expected, DEFAULT_LOAD_FACTOR);
	}

	/** Creates a new hash big set with initial expected {@link Hash#DEFAULT_INITIAL_SIZE} elements
	 * and {@link Hash#DEFAULT_LOAD_FACTOR} as load factor.
	 */

	public OPEN_HASH_BIG_SET() {
		this(DEFAULT_INITIAL_SIZE, DEFAULT_LOAD_FACTOR);
	}

	/** Creates a new hash big set copying a given collection.
	 *
	 * @param c a {@link Collection} to be copied into the new hash big set.
	 * @param f the load factor.
	 */

	public OPEN_HASH_BIG_SET(final Collection<? extends KEY_GENERIC_CLASS> c, final float f) {
		this(c.size(), f);
		addAll(c);
	}

	/** Creates a new hash big set  with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor
	 * copying a given collection.
	 *
	 * @param c a {@link Collection} to be copied into the new hash big set.
	 */

	public OPEN_HASH_BIG_SET(final Collection<? extends KEY_GENERIC_CLASS> c) {
		this(c, DEFAULT_LOAD_FACTOR);
	}

	/** Creates a new hash big set copying a given type-specific collection.
	 *
	 * @param c a type-specific collection to be copied into the new hash big set.
	 * @param f the load factor.
	 */

	public OPEN_HASH_BIG_SET(final COLLECTION KEY_EXTENDS_GENERIC c, final float f) {
		this(c.size(), f);
		addAll(c);
	}

	/** Creates a new hash big set  with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor
	 * copying a given type-specific collection.
	 *
	 * @param c a type-specific collection to be copied into the new hash big set.
	 */

	public OPEN_HASH_BIG_SET(final COLLECTION KEY_EXTENDS_GENERIC c) {
		this(c, DEFAULT_LOAD_FACTOR);
	}

	/** Creates a new hash big set using elements provided by a type-specific iterator.
	 *
	 * @param i a type-specific iterator whose elements will fill the new hash big set.
	 * @param f the load factor.
	 */

	public OPEN_HASH_BIG_SET(final STD_KEY_ITERATOR KEY_EXTENDS_GENERIC i, final float f) {
		this(DEFAULT_INITIAL_SIZE, f);
		while(i.hasNext()) add(i.NEXT_KEY());
	}

	/** Creates a new hash big set with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor using elements provided by a type-specific iterator.
	 *
	 * @param i a type-specific iterator whose elements will fill the new hash big set.
	 */

	public OPEN_HASH_BIG_SET(final STD_KEY_ITERATOR KEY_EXTENDS_GENERIC i) {
		this(i, DEFAULT_LOAD_FACTOR);
	}


#if KEYS_PRIMITIVE

	/** Creates a new hash big set using elements provided by an iterator.
	 *
	 * @param i an iterator whose elements will fill the new hash big set.
	 * @param f the load factor.
	 */

	public OPEN_HASH_BIG_SET(final Iterator<?> i, final float f) {
		this(ITERATORS.AS_KEY_ITERATOR(i), f);
	}
	/** Creates a new hash big set with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor using elements provided by an iterator.
	 *
	 * @param i an iterator whose elements will fill the new hash big set.
	 */

	public OPEN_HASH_BIG_SET(final Iterator<?> i) {
		this(ITERATORS.AS_KEY_ITERATOR(i));
	}

#endif


	/** Creates a new hash big set and fills it with the elements of a given array.
	 *
	 * @param a an array whose elements will be used to fill the new hash big set.
	 * @param offset the first element to use.
	 * @param length the number of elements to use.
	 * @param f the load factor.
	 */

	public OPEN_HASH_BIG_SET(final KEY_GENERIC_TYPE[] a, final int offset, final int length, final float f) {
		this(length < 0 ? 0 : length, f);
		ARRAYS.ensureOffsetLength(a, offset, length);
		for(int i = 0; i < length; i++) add(a[offset + i]);
	}

	/** Creates a new hash big set with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor and fills it with the elements of a given array.
	 *
	 * @param a an array whose elements will be used to fill the new hash big set.
	 * @param offset the first element to use.
	 * @param length the number of elements to use.
	 */

	public OPEN_HASH_BIG_SET(final KEY_GENERIC_TYPE[] a, final int offset, final int length) {
		this(a, offset, length, DEFAULT_LOAD_FACTOR);
	}

	/** Creates a new hash big set copying the elements of an array.
	 *
	 * @param a an array to be copied into the new hash big set.
	 * @param f the load factor.
	 */

	public OPEN_HASH_BIG_SET(final KEY_GENERIC_TYPE[] a, final float f) {
		this(a, 0, a.length, f);
	}

	/** Creates a new hash big set with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor
	 * copying the elements of an array.
	 *
	 * @param a an array to be copied into the new hash big set.
	 */

	public OPEN_HASH_BIG_SET(final KEY_GENERIC_TYPE[] a) {
		this(a, DEFAULT_LOAD_FACTOR);
	}

	private long realSize() {
		return containsNull ? size - 1 : size;
	}

	private void ensureCapacity(final long capacity) {
		final long needed = bigArraySize(capacity, f);
		if (needed > n) rehash(needed);
	}

	@Override
	public boolean addAll(Collection<? extends KEY_GENERIC_CLASS> c) {
		final long size = c instanceof Size64 ? ((Size64)c).size64() : c.size();
		// The resulting collection will be at least c.size() big
		if (f <= .5) ensureCapacity(size); // The resulting collection will be sized for c.size() elements
		else ensureCapacity(size64() + size); // The resulting collection will be sized for size() + c.size() elements
		return super.addAll(c);
	}

#if KEYS_PRIMITIVE
	@Override
	public boolean addAll(COLLECTION c) {
		final long size = c instanceof Size64 ? ((Size64)c).size64() : c.size();
		if (f <= .5) ensureCapacity(size); // The resulting collection will be size for c.size() elements
		else ensureCapacity(size64() + size); // The resulting collection will be sized for size() + c.size() elements
		return super.addAll(c);
	}
#endif

	@Override
	public boolean add(final KEY_GENERIC_TYPE k) {
		int displ, base;

		if (KEY_IS_NULL(k)) {
			if (containsNull) return false;
			containsNull = true;
		}
		else {
			KEY_GENERIC_TYPE curr;
			final KEY_GENERIC_TYPE[][] key = this.key;
			final long h = KEY2LONGHASH(k);

			// The starting point.
			if (! KEY_IS_NULL(curr = key[base = (int)((h & mask) >>> BigArrays.SEGMENT_SHIFT)][displ = (int)(h & segmentMask)])) {
				if (KEY_EQUALS_NOT_NULL(curr, k)) return false;
				while(! KEY_IS_NULL(curr = key[base = (base + ((displ = (displ + 1) & segmentMask) == 0 ? 1 : 0)) & baseMask][displ]))
					if (KEY_EQUALS_NOT_NULL(curr, k)) return false;
			}

			key[base][displ] = k;
		}

		if (size++ >= maxFill) rehash(2 * n);
		if (ASSERTS) checkTable();
		return true;
	}

#if KEY_CLASS_Object
	/** Add a random element if not present, get the existing value if already present.
	 *
	 * This is equivalent to (but faster than) doing a:
	 * <pre>
	 * K exist = set.get(k);
	 * if (exist == null) {
	 *   set.add(k);
	 *   exist = k;
	 * }
	 * </pre>
	 */
	public KEY_GENERIC_TYPE addOrGet(final KEY_GENERIC_TYPE k) {
		int displ, base;

		if (KEY_IS_NULL(k)) {
			if (containsNull) return null;
			containsNull = true;
		}
		else {
			KEY_GENERIC_TYPE curr;
			final KEY_GENERIC_TYPE[][] key = this.key;
			final long h = KEY2LONGHASH(k);

			// The starting point.
			if (! KEY_IS_NULL(curr = key[base = (int)((h & mask) >>> BigArrays.SEGMENT_SHIFT)][displ = (int)(h & segmentMask)])) {
				if (KEY_EQUALS_NOT_NULL(curr, k)) return curr;
				while(! KEY_IS_NULL(curr = key[base = (base + ((displ = (displ + 1) & segmentMask) == 0 ? 1 : 0)) & baseMask][displ]))
					if (KEY_EQUALS_NOT_NULL(curr, k)) return curr;
			}

			key[base][displ] = k;
		}

		if (size++ >= maxFill) rehash(2 * n);
		if (ASSERTS) checkTable();
		return k;
	}
#endif

	/** 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(long pos) {
		// Shift entries with the same hash.
		long last, slot;
		final KEY_GENERIC_TYPE[][] key = this.key;

		for(;;) {
			pos = ((last = pos) + 1) & mask;

			for(;;) {
				if (KEY_IS_NULL(BIG_ARRAYS.get(key, pos))) {
					BIG_ARRAYS.set(key, last, KEY_NULL);
					return;
				}
				slot = KEY2LONGHASH(BIG_ARRAYS.get(key, pos)) & mask;
				if (last <= pos ? last >= slot || slot > pos : last >= slot && slot > pos) break;
				pos = (pos + 1) & mask;
			}

			BIG_ARRAYS.set(key, last, BIG_ARRAYS.get(key, pos));
		}
	}

	private boolean removeEntry(final int base, final int displ) {
		size--;
		shiftKeys(base * (long)BigArrays.SEGMENT_SIZE + displ);
		if (n > minN && size < maxFill / 4 && n > DEFAULT_INITIAL_SIZE) rehash(n / 2);
		return true;
	}

	private boolean removeNullEntry() {
		containsNull = false;
		size--;
		if (n > minN && size < maxFill / 4 && n > DEFAULT_INITIAL_SIZE) rehash(n / 2);
		return true;
	}

	@Override
	public boolean remove(final KEY_TYPE k) {
		if (KEY_IS_NULL(k)) {
			if (containsNull) return removeNullEntry();
			return false;
		}

		KEY_GENERIC_TYPE curr;
		final KEY_GENERIC_TYPE[][] key = this.key;
		final long h = KEY2LONGHASH(k);
		int displ, base;

		// The starting point.
		if (KEY_IS_NULL(curr = key[base = (int)((h & mask) >>> BigArrays.SEGMENT_SHIFT)][displ = (int)(h & segmentMask)])) return false;
		if (KEY_EQUALS_NOT_NULL(curr, k)) return removeEntry(base, displ);
		while(true) {
			if (KEY_IS_NULL(curr = key[base = (base + ((displ = (displ + 1) & segmentMask) == 0 ? 1 : 0)) & baseMask][displ])) return false;
			if (KEY_EQUALS_NOT_NULL(curr, k)) return removeEntry(base, displ);
		}
	}

	@Override
	public boolean contains(final KEY_TYPE k) {
		if (KEY_IS_NULL(k)) return containsNull;

		KEY_GENERIC_TYPE curr;
		final KEY_GENERIC_TYPE[][] key = this.key;
		final long h = KEY2LONGHASH(k);
		int displ, base;

		// The starting point.
		if (KEY_IS_NULL(curr = key[base = (int)((h & mask) >>> BigArrays.SEGMENT_SHIFT)][displ = (int)(h & segmentMask)])) return false;
		if (KEY_EQUALS_NOT_NULL(curr, k)) return true;
		while(true) {
			if (KEY_IS_NULL(curr = key[base = (base + ((displ = (displ + 1) & segmentMask) == 0 ? 1 : 0)) & baseMask][displ])) return false;
			if (KEY_EQUALS_NOT_NULL(curr, k)) return true;
		}
	}

#if KEY_CLASS_Object
	/** Returns the element of this set that is equal to the given key, or {@code null}.
	 * @return the element of this set that is equal to the given key, or {@code null}.
	 */
	public K get(final KEY_TYPE k) {
		if (k == null) return null; // This is correct independently of the value of containsNull

		KEY_GENERIC_TYPE curr;
		final KEY_GENERIC_TYPE[][] key = this.key;
		final long h = KEY2LONGHASH(k);
		int displ, base;

		// The starting point.
		if (KEY_IS_NULL(curr = key[base = (int)((h & mask) >>> BigArrays.SEGMENT_SHIFT)][displ = (int)(h & segmentMask)])) return null;
		if (KEY_EQUALS_NOT_NULL(curr, k)) return curr;
		while(true) {
			if (KEY_IS_NULL(curr = key[base = (base + ((displ = (displ + 1) & segmentMask) == 0 ? 1 : 0)) & baseMask][displ])) return null;
			if (KEY_EQUALS_NOT_NULL(curr, k)) return curr;
		}
	}
#endif

	/* Removes all elements from this set.
	 *
	 */

	/** {@inheritDoc}
	 *
	 * <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(long)}.
	 */
	@Override
	public void clear() {
		if (size == 0) return;
		size = 0;
		containsNull = false;
		BIG_ARRAYS.fill(key, KEY_NULL);
	}



	/** An iterator over a hash big set. */

	private class SetIterator implements KEY_ITERATOR KEY_GENERIC {
		/** The base of the last entry returned, if positive or zero; initially, the number of components
			of the key array. If negative, the last element returned was
			that of index {@code - base - 1} from the {@link #wrapped} list. */
		int base = key.length;
		/** The displacement of the last entry returned; initially, zero. */
		int displ;
		/** The index of the last entry that has been returned (or {@link Long#MIN_VALUE} if {@link #base} is negative).
			It is -1 if either we did not return an entry yet, or the last returned entry has been removed. */
		long last = -1;
		/** A downward counter measuring how many entries must still be returned. */
		long c = size;
		/** A boolean telling us whether we should return the null key. */
		boolean mustReturnNull = OPEN_HASH_BIG_SET.this.containsNull;
		/** A lazily allocated list containing elements that have wrapped around the table because of removals. */
		ARRAY_LIST KEY_GENERIC wrapped;

		@Override
		public boolean hasNext() { return c != 0; }

		@Override
		public KEY_GENERIC_TYPE NEXT_KEY() {
			if (! hasNext()) throw new NoSuchElementException();
			c--;

			if (mustReturnNull) {
				mustReturnNull = false;
				last = n;
				return KEY_NULL;
			}

			final KEY_GENERIC_TYPE[][] key = OPEN_HASH_BIG_SET.this.key;

			for(;;) {
				if (displ == 0 && base <= 0) {
					// We are just enumerating elements from the wrapped list.
					last = Long.MIN_VALUE;
					return wrapped.GET_KEY(- (--base) - 1);
				}

				if (displ-- == 0) displ = key[--base].length - 1;

				final KEY_GENERIC_TYPE k = key[base][displ];
				if (! KEY_IS_NULL(k)) {
					last = base * (long)BigArrays.SEGMENT_SIZE + displ;
					return k;
				}
			}
		}

		/** Shifts left entries with the specified hash code, starting at the specified position,
		 * and empties the resulting free entry.
		 *
		 * @param pos a starting position.
		 */
		private final void shiftKeys(long pos) {
			// Shift entries with the same hash.
			long last, slot;
			KEY_GENERIC_TYPE curr;
			final KEY_GENERIC_TYPE[][] key = OPEN_HASH_BIG_SET.this.key;

			for(;;) {
				pos = ((last = pos) + 1) & mask;

				for(;;) {
					if(KEY_IS_NULL(curr = BIG_ARRAYS.get(key, pos))) {
						BIG_ARRAYS.set(key, last, KEY_NULL);
						return;
					}
					slot = KEY2LONGHASH(curr) & mask;
					if (last <= pos ? last >= slot || slot > pos : last >= slot && slot > pos) break;
					pos = (pos + 1) & mask;
				}

				if (pos < last) {	// Wrapped entry.
					if (wrapped == null) wrapped = new ARRAY_LIST KEY_GENERIC_DIAMOND();
					wrapped.add(BIG_ARRAYS.get(key, pos));
				}

				BIG_ARRAYS.set(key, last, curr);
			}
		}

		@Override
		public void remove() {
			if (last == -1) throw new IllegalStateException();
			if (last == n) OPEN_HASH_BIG_SET.this.containsNull = false;
			else if (base >= 0) shiftKeys(last);
			else {
				// We're removing wrapped entries.
#if KEYS_REFERENCE
				OPEN_HASH_BIG_SET.this.remove(wrapped.set(- base - 1, null));
#else
				OPEN_HASH_BIG_SET.this.remove(wrapped.GET_KEY(- base - 1));
#endif
				last = -1; // Note that we must not decrement size
				return;
			}

			size--;
			last = -1; // You can no longer remove this entry.
			if (ASSERTS) checkTable();
		}
	}

	@Override
	public KEY_ITERATOR KEY_GENERIC iterator() {
		return new SetIterator();
	}


	/** Rehashes this set, 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 set.
	 * @see #trim(long)
	 */

	public boolean trim() {
		final long l = bigArraySize(size, f);
		if (l >= n || size > maxFill(l, f)) return true;
		try {
			rehash(l);
		}
		catch(OutOfMemoryError cantDoIt) { return false; }
		return true;
	}

	/** Rehashes this set if the table is too large.
	 *
	 * <p>Let <var>N</var> be the smallest table size that can hold
	 * <code>max(n,{@link #size64()})</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 set in a table of size
	 * <var>N</var>.
	 *
	 * <p>This method is useful when reusing sets.  {@linkplain #clear() Clearing a
	 * set} leaves the table size untouched. If you are reusing a set
	 * 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 sets.
	 *
	 * @param n the threshold for the trimming.
	 * @return true if there was enough memory to trim the set.
	 * @see #trim()
	 */

	public boolean trim(final long n) {
		final long l = bigArraySize(n, f);
		if (this.n <= l) return true;
		try {
			rehash(l);
		}
		catch(OutOfMemoryError cantDoIt) { return false; }
		return true;
	}

	/** Resizes the set.
	 *
	 * <p>This method implements the basic rehashing strategy, and may be
	 * overriden 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
	 */

	SUPPRESS_WARNINGS_KEY_UNCHECKED
	protected void rehash(final long newN) {
		final KEY_GENERIC_TYPE key[][] = this.key;
		final KEY_GENERIC_TYPE newKey[][] = KEY_GENERIC_BIG_ARRAY_CAST BIG_ARRAYS.newBigArray(newN);
		final long mask = newN - 1; // Note that this is used by the hashing macro
		final int newSegmentMask = newKey[0].length - 1;
		final int newBaseMask = newKey.length - 1;

		int base = 0, displ = 0, b, d;
		long h;
		KEY_GENERIC_TYPE k;

		for(long i = realSize(); i-- != 0;) {

			while(KEY_IS_NULL(key[base][displ])) base = (base + ((displ = (displ + 1) & segmentMask) == 0 ? 1 : 0));

			k = key[base][displ];
			h = KEY2LONGHASH(k);

			// The starting point.
			if (! KEY_IS_NULL(newKey[b = (int)((h & mask) >>> BigArrays.SEGMENT_SHIFT)][d = (int)(h & newSegmentMask)]))
				while(! KEY_IS_NULL(newKey[b = (b + ((d = (d + 1) & newSegmentMask) == 0 ? 1 : 0)) & newBaseMask][d]));

			newKey[b][d] = k;

			base = (base + ((displ = (displ + 1) & segmentMask) == 0 ? 1 : 0));
		}

		this.n = newN;
		this.key = newKey;
		initMasks();
		maxFill = maxFill(n, f);
	}

	@Deprecated
	@Override
	public int size() {
		return (int)Math.min(Integer.MAX_VALUE, size);
	}

	@Override
	public long size64() {
		return size;
	}

	@Override
	public boolean isEmpty() {
		return size == 0;
	}



	/** Returns a deep copy of this big set.
	 *
	 * <p>This method performs a deep copy of this big hash set; the data stored in the
	 * set, however, is not cloned. Note that this makes a difference only for object keys.
	 *
	 *  @return a deep copy of this big set.
	 */
	@Override
	SUPPRESS_WARNINGS_KEY_UNCHECKED
	public OPEN_HASH_BIG_SET KEY_GENERIC clone() {
		OPEN_HASH_BIG_SET KEY_GENERIC c;
		try {
			c = (OPEN_HASH_BIG_SET KEY_GENERIC)super.clone();
		}
		catch(CloneNotSupportedException cantHappen) {
			throw new InternalError();
		}
		c.key = BIG_ARRAYS.copy(key);
		c.containsNull = containsNull;
		return c;
	}

	/** Returns a hash code for this set.
	 *
	 * 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 set.
	 */

	@Override
	public int hashCode() {
		final KEY_GENERIC_TYPE key[][] = this.key;
		int h = 0, base = 0, displ = 0;

		for(long j = realSize(); j-- != 0;) {
			while(KEY_IS_NULL(key[base][displ])) base = (base + ((displ = (displ + 1) & segmentMask) == 0 ? 1 : 0));
#if KEYS_REFERENCE
			if (this != key[base][displ])
#endif
				h += KEY2JAVAHASH_NOT_NULL(key[base][displ]);
			base = (base + ((displ = (displ + 1) & segmentMask) == 0 ? 1 : 0));
		}
		return h;
	}


	private void writeObject(java.io.ObjectOutputStream s) throws java.io.IOException {
		final KEY_ITERATOR KEY_GENERIC i = iterator();
		s.defaultWriteObject();
		for(long j = size; j-- != 0;) s.WRITE_KEY(i.NEXT_KEY());
	}


	SUPPRESS_WARNINGS_KEY_UNCHECKED
	private void readObject(java.io.ObjectInputStream s) throws java.io.IOException, ClassNotFoundException {
		s.defaultReadObject();

		n = bigArraySize(size, f);
		maxFill = maxFill(n, f);

		final KEY_GENERIC_TYPE[][] key = this.key = KEY_GENERIC_BIG_ARRAY_CAST BIG_ARRAYS.newBigArray(n);

		initMasks();

		long h;
		KEY_GENERIC_TYPE k;
		int base, displ;

		for(long i = size; i-- != 0;) {
			k = KEY_GENERIC_CAST s.READ_KEY();

			if (KEY_IS_NULL(k)) containsNull = true;
			else {
				h = KEY2LONGHASH(k);
				if (! KEY_IS_NULL(key[base = (int)((h & mask) >>> BigArrays.SEGMENT_SHIFT)][displ = (int)(h & segmentMask)]))
					while(! KEY_IS_NULL(key[base = (base + ((displ = (displ + 1) & segmentMask) == 0 ? 1 : 0)) & baseMask][displ]));
				key[base][displ] = k;
			}
		}

		if (ASSERTS) checkTable();
	}


#ifdef ASSERTS_CODE
	private void checkTable() {
		assert (n & -n) == n : "Table length is not a power of two: " + n;
		assert n == BIG_ARRAYS.length(key);
		long n = this.n;
		while(n-- != 0)
			if (! KEY_IS_NULL(BIG_ARRAYS.get(key, n)) && ! contains(BIG_ARRAYS.get(key, n)))
				throw new AssertionError("Hash table has key " + BIG_ARRAYS.get(key, n) + " marked as occupied, but the key does not belong to the table");

#if KEYS_PRIMITIVE
		java.util.HashSet<KEY_GENERIC_CLASS> s = new java.util.HashSet<KEY_GENERIC_CLASS> ();
#else
		java.util.HashSet<Object> s = new java.util.HashSet<Object>();
#endif

		for(long i = size(); i-- != 0;)
			if (! KEY_IS_NULL(BIG_ARRAYS.get(key, i)) && ! s.add(BIG_ARRAYS.get(key, i))) throw new AssertionError("Key " + BIG_ARRAYS.get(key, i) + " appears twice");

	}
#else
	private void checkTable() {}
#endif

#ifdef TEST

	private static long seed = System.currentTimeMillis();
	private static java.util.Random r = new java.util.Random(seed);

	private static KEY_TYPE genKey() {
#if KEY_CLASS_Byte || KEY_CLASS_Short || KEY_CLASS_Character
		return (KEY_TYPE)(r.nextInt());
#elif KEYS_PRIMITIVE
		return r.NEXT_KEY();
#elif KEY_CLASS_Object
		return Integer.toBinaryString(r.nextInt());
#else
		return new java.io.Serializable() {};
#endif
	}


	private static final class ArrayComparator implements java.util.Comparator {
		public int compare(Object a, Object b) {
			byte[] aa = (byte[])a;
			byte[] bb = (byte[])b;
			int length = Math.min(aa.length, bb.length);
			for(int i = 0; i < length; i++) {
				if (aa[i] < bb[i]) return -1;
				if (aa[i] > bb[i]) return 1;
			}
			return aa.length == bb.length ? 0 : (aa.length < bb.length ? -1 : 1);
		}
	}

	private static final class MockSet extends java.util.TreeSet {
		private java.util.List list = new java.util.ArrayList();

		public MockSet(java.util.Comparator c) { super(c); }

		public boolean add(Object k) {
			if (! contains(k)) list.add(k);
			return super.add(k);
		}

		public boolean addAll(Collection c) {
			java.util.Iterator i = c.iterator();
			boolean result = false;
			while(i.hasNext()) result |= add(i.next());
			return result;
		}

		public boolean removeAll(Collection c) {
			java.util.Iterator i = c.iterator();
			boolean result = false;
			while(i.hasNext()) result |= remove(i.next());
			return result;
		}

		public boolean remove(Object k) {
			if (contains(k)) {
				int i = list.size();
				while(i-- != 0) if (comparator().compare(list.get(i), k) == 0) {
					list.remove(i);
					break;
				}
			}
			return super.remove(k);
		}

		private void justRemove(Object k) { super.remove(k); }

		public java.util.Iterator iterator() {
			return new java.util.Iterator() {
					final java.util.Iterator iterator = list.iterator();
					Object curr;
					public Object next() { return curr = iterator.next(); }
					public boolean hasNext() { return iterator.hasNext(); }
					public void remove() {
						justRemove(curr);
						iterator.remove();
					}
				};
		}
	}

	private static java.text.NumberFormat format = new java.text.DecimalFormat("#,###.00");
	private static java.text.FieldPosition fp = new java.text.FieldPosition(0);

	private static String format(double d) {
		StringBuffer s = new StringBuffer();
		return format.format(d, s, fp).toString();
	}

	private static void speedTest(int n, float f, boolean comp) {
		int i, j;
		OPEN_HASH_BIG_SET m;
		java.util.HashSet t;

		KEY_TYPE k[] = new KEY_TYPE[n];
		KEY_TYPE nk[] = new KEY_TYPE[n];
		long ms;

		for(i = 0; i < n; i++) {
			k[i] = genKey();
			nk[i] = genKey();
		}

		double totAdd = 0, totYes = 0, totNo = 0, totIter = 0, totRemYes = 0, totRemNo = 0, d;

		if (comp) { for(j = 0; j < 20; j++) {

			t = new java.util.HashSet(16);

			/* We add pairs to t. */
			ms = System.currentTimeMillis();
			for(i = 0; i < n;  i++) t.add(KEY2OBJ(k[i]));
			d = 1.0 * n / (System.currentTimeMillis() - ms);
			if (j > 2) totAdd += d;
			System.out.print("Add: " + format(d) +" K/s ");

			/* We check for pairs in t. */
			ms = System.currentTimeMillis();
			for(i = 0; i < n;  i++) t.contains(KEY2OBJ(k[i]));
			d = 1.0 * n / (System.currentTimeMillis() - ms);
			if (j > 2) totYes += d;
			System.out.print("Yes: " + format(d) +" K/s ");

			/* We check for pairs not in t. */
			ms = System.currentTimeMillis();
			for(i = 0; i < n;  i++) t.contains(KEY2OBJ(nk[i]));
			d = 1.0 * n / (System.currentTimeMillis() - ms);
			if (j > 2) totNo += d;
			System.out.print("No: " + format(d) +" K/s ");

			/* We iterate on t. */
			ms = System.currentTimeMillis();
			for(java.util.Iterator it = t.iterator(); it.hasNext(); it.next());
			d = 1.0 * n / (System.currentTimeMillis() - ms);
			if (j > 2) totIter += d;
			System.out.print("Iter: " + format(d) +" K/s ");

			/* We delete pairs not in t. */
			ms = System.currentTimeMillis();
			for(i = 0; i < n;  i++) t.remove(KEY2OBJ(nk[i]));
			d = 1.0 * n / (System.currentTimeMillis() - ms);
			if (j > 2) totRemNo += d;
			System.out.print("RemNo: " + format(d) +" K/s ");

			/* We delete pairs in t. */
			ms = System.currentTimeMillis();
			for(i = 0; i < n;  i++) t.remove(KEY2OBJ(k[i]));
			d = 1.0 * n / (System.currentTimeMillis() - ms);
			if (j > 2) totRemYes += d;
			System.out.print("RemYes: " + format(d) +" K/s ");

			System.out.println();
		}

		System.out.println();
		System.out.println("java.util Add: " + format(totAdd/(j-3)) + " K/s Yes: " + format(totYes/(j-3)) + " K/s No: " + format(totNo/(j-3)) + " K/s Iter: " + format(totIter/(j-3)) + " K/s RemNo: " + format(totRemNo/(j-3)) + " K/s RemYes: " + format(totRemYes/(j-3)) + "K/s");

		System.out.println();

		totAdd = totYes = totNo = totIter = totRemYes = totRemNo = 0;
		}

		for(j = 0; j < 20; j++) {

			m = new OPEN_HASH_BIG_SET(16, f);

			/* We add pairs to m. */
			ms = System.currentTimeMillis();
			for(i = 0; i < n;  i++) m.add(k[i]);
			d = 1.0 * n / (System.currentTimeMillis() - ms);
			if (j > 2) totAdd += d;
			System.out.print("Add: " + format(d) +" K/s ");

			/* We check for pairs in m. */
			ms = System.currentTimeMillis();
			for(i = 0; i < n;  i++) m.contains(k[i]);
			d = 1.0 * n / (System.currentTimeMillis() - ms);
			if (j > 2) totYes += d;
			System.out.print("Yes: " + format(d) +" K/s ");

			/* We check for pairs not in m. */
			ms = System.currentTimeMillis();
			for(i = 0; i < n;  i++) m.contains(nk[i]);
			d = 1.0 * n / (System.currentTimeMillis() - ms);
			if (j > 2) totNo += d;
			System.out.print("No: " + format(d) +" K/s ");

			/* We iterate on m. */
			ms = System.currentTimeMillis();
			for(KEY_ITERATOR it = (KEY_ITERATOR)m.iterator(); it.hasNext(); it.NEXT_KEY());
			d = 1.0 * n / (System.currentTimeMillis() - ms);
			if (j > 2) totIter += d;
			System.out.print("Iter: " + format(d) +" K/s ");

			/* We delete pairs not in m. */
			ms = System.currentTimeMillis();
			for(i = 0; i < n;  i++) m.remove(nk[i]);
			d = 1.0 * n / (System.currentTimeMillis() - ms);
			if (j > 2) totRemNo += d;
			System.out.print("RemNo: " + format(d) +" K/s ");

			/* We delete pairs in m. */
			ms = System.currentTimeMillis();
			for(i = 0; i < n;  i++) m.remove(k[i]);
			d = 1.0 * n / (System.currentTimeMillis() - ms);
			if (j > 2) totRemYes += d;
			System.out.print("RemYes: " + format(d) +" K/s ");

			System.out.println();
		}


		System.out.println();
		System.out.println("fastutil  Add: " + format(totAdd/(j-3)) + " K/s Yes: " + format(totYes/(j-3)) + " K/s No: " + format(totNo/(j-3)) + " K/s Iter: " + format(totIter/(j-3)) + " K/s RemNo: " + format(totRemNo/(j-3)) + " K/s RemYes: " + format(totRemYes/(j-3)) + " K/s");

		System.out.println();
	}


	private static void fatal(String msg) {
		System.out.println(msg);
		System.exit(1);
	}

	private static void ensure(boolean cond, String msg) {
		if (cond) return;
		fatal(msg);
	}


	private static void printProbes(OPEN_HASH_BIG_SET m) {
		long totProbes = 0;
		double totSquareProbes = 0;
		int maxProbes = 0;
		final double f = (double)m.size / m.n;
		for(int i = 0, c = 0; i < m.n; i++) {
			if (! KEY_IS_NULL(BIG_ARRAYS.get(m.key, i))) c++;
			else {
				if (c != 0) {
					final long p = (c + 1) * (c + 2) / 2;
					totProbes += p;
					totSquareProbes += (double)p * p;
				}
				maxProbes = Math.max(c, maxProbes);
				c = 0;
				totProbes++;
				totSquareProbes++;
			}
		}

		final double expected = (double)totProbes / m.n;
		System.err.println("Expected probes: " + (
			3 * Math.sqrt(3) * (f / ((1 - f) * (1 - f))) + 4 / (9 * f) - 1
		) + "; actual: " + expected + "; stddev: " + Math.sqrt(totSquareProbes / m.n - expected * expected)  + "; max probes: " + maxProbes);
	}
	private static void runTest(int n, float f) {
		int c;
		OPEN_HASH_BIG_SET m = new OPEN_HASH_BIG_SET(Hash.DEFAULT_INITIAL_SIZE, f);
		java.util.Set t = new java.util.HashSet();

		/* First of all, we fill t with random data. */

		for(int i=0; i<f * n;  i++) t.add(KEY2OBJ(genKey()));

		/* Now we add to m the same data */

		m.addAll(t);

		if (!m.equals(t)) System.out.println("Error (" + seed + "): !m.equals(t) after insertion");
		if (!t.equals(m)) System.out.println("Error (" + seed + "): !t.equals(m) after insertion");
		printProbes(m);

		/* Now we check that m actually holds that data. */

		for(java.util.Iterator i=t.iterator(); i.hasNext();) {
			Object e = i.next();
			if (!m.contains(e)) {
				System.out.println("Error (" + seed + "): m and t differ on a key ("+e+") after insertion (iterating on t)");
				System.exit(1);
			}
		}

		/* Now we check that m actually holds that data, but iterating on m. */

		c = 0;
		for(java.util.Iterator i=m.iterator(); i.hasNext();) {
			Object e = i.next();
			c++;
			if (!t.contains(e)) {
				System.out.println("Error (" + seed + "): m and t differ on a key ("+e+") after insertion (iterating on m)");
				System.exit(1);
			}
		}

		if (c != t.size()) {
			System.out.println("Error (" + seed + "): m has only " + c + " keys instead of " + t.size() + " after insertion (iterating on m)");
			System.exit(1);
		}
		/* Now we check that inquiries about random data give the same answer in m and t. For
		   m we use the polymorphic method. */

		for(int i=0; i<n;  i++) {
			KEY_TYPE T = genKey();
			if (m.contains(T) != t.contains(KEY2OBJ(T))) {
				System.out.println("Error (" + seed + "): divergence in keys between t and m (polymorphic method)");
				System.exit(1);
			}
		}

		/* Again, we check that inquiries about random data give the same answer in m and t, but
		   for m we use the standard method. */

		for(int i=0; i<n;  i++) {
			KEY_TYPE T = genKey();
			if (m.contains(KEY2OBJ(T)) != t.contains(KEY2OBJ(T))) {
				System.out.println("Error (" + seed + "): divergence between t and m (standard method)");
				System.exit(1);
			}
		}


		/* Now we put and remove random data in m and t, checking that the result is the same. */

		for(int i=0; i<20*n;  i++) {
			KEY_TYPE T = genKey();
			if (m.add(KEY2OBJ(T)) != t.add(KEY2OBJ(T))) {
				System.out.println("Error (" + seed + "): divergence in add() between t and m");
				System.exit(1);
			}
			T = genKey();
			if (m.remove(KEY2OBJ(T)) != t.remove(KEY2OBJ(T))) {
				System.out.println("Error (" + seed + "): divergence in remove() between t and m");
				System.exit(1);
			}
		}

		if (!m.equals(t)) System.out.println("Error (" + seed + "): !m.equals(t) after removal");
		if (!t.equals(m)) System.out.println("Error (" + seed + "): !t.equals(m) after removal");

		/* Now we check that m actually holds that data. */

		for(java.util.Iterator i=t.iterator(); i.hasNext();) {
			Object e = i.next();
			if (!m.contains(e)) {
				System.out.println("Error (" + seed + "): m and t differ on a key ("+e+") after removal (iterating on t)");
				System.exit(1);
			}
		}

		/* Now we check that m actually holds that data, but iterating on m. */

		for(java.util.Iterator i=m.iterator(); i.hasNext();) {
			Object e = i.next();
			if (!t.contains(e)) {
				System.out.println("Error (" + seed + "): m and t differ on a key ("+e+") after removal (iterating on m)");
				System.exit(1);
			}
		}

		printProbes(m);

		/* Now we make m into an array, make it again a set and check it is OK. */
		KEY_TYPE a[] = m.TO_KEY_ARRAY();

		if (!new OPEN_HASH_BIG_SET(a).equals(m))
			System.out.println("Error (" + seed + "): toArray() output (or array-based constructor) is not OK");

		/* Now we check cloning. */

		ensure(m.equals(((OPEN_HASH_BIG_SET)m).clone()), "Error (" + seed + "): m does not equal m.clone()");
		ensure(((OPEN_HASH_BIG_SET)m).clone().equals(m), "Error (" + seed + "): m.clone() does not equal m");

		int h = m.hashCode();

		/* Now we save and read m. */

		try {
			java.io.File ff = new java.io.File("it.unimi.dsi.fastutil.test");
			java.io.OutputStream os = new java.io.FileOutputStream(ff);
			java.io.ObjectOutputStream oos = new java.io.ObjectOutputStream(os);

			oos.writeObject(m);
			oos.close();

			java.io.InputStream is = new java.io.FileInputStream(ff);
			java.io.ObjectInputStream ois = new java.io.ObjectInputStream(is);

			m = (OPEN_HASH_BIG_SET)ois.readObject();
			ois.close();
			ff.delete();
		}
		catch(Exception e) {
			e.printStackTrace();
			System.exit(1);
		}

#if !KEY_CLASS_Reference
		if (m.hashCode() != h) System.out.println("Error (" + seed + "): hashCode() changed after save/read");

		printProbes(m);

		/* Now we check that m actually holds that data, but iterating on m. */

		for(java.util.Iterator i=m.iterator(); i.hasNext();) {
			Object e = i.next();
			if (!t.contains(e)) {
				System.out.println("Error (" + seed + "): m and t differ on a key ("+e+") after save/read");
				System.exit(1);
			}
		}
#else
		m.clear();
		m.addAll(t);
#endif

		/* Now we put and remove random data in m and t, checking that the result is the same. */

		for(int i=0; i<20*n;  i++) {
			KEY_TYPE T = genKey();
			if (m.add(KEY2OBJ(T)) != t.add(KEY2OBJ(T))) {
				System.out.println("Error (" + seed + "): divergence in add() between t and m after save/read");
				System.exit(1);
			}
			T = genKey();
			if (m.remove(KEY2OBJ(T)) != t.remove(KEY2OBJ(T))) {
				System.out.println("Error (" + seed + "): divergence in remove() between t and m after save/read");
				System.exit(1);
			}
		}

		if (!m.equals(t)) System.out.println("Error (" + seed + "): !m.equals(t) after post-save/read removal");
		if (!t.equals(m)) System.out.println("Error (" + seed + "): !t.equals(m) after post-save/read removal");


		/* Now we take out of m everything, and check that it is empty. */

		for(java.util.Iterator i=m.iterator(); i.hasNext();) { i.next(); i.remove();}

		if (!m.isEmpty())  {
			System.out.println("Error (" + seed + "): m is not empty (as it should be)");
			System.exit(1);
		}

#if KEY_CLASS_Integer || KEY_CLASS_Long
		m = new OPEN_HASH_BIG_SET(n, f);
		t.clear();
		int x;

		/* Now we torture-test the hash table. This part is implemented only for integers and longs. */

		int p = m.key.length - 1;

		for(int i=0; i<p; i++) {
			for (int j=0; j<20; j++) {
				m.add(i+(r.nextInt() % 10)*p);
				m.remove(i+(r.nextInt() % 10)*p);
			}

			for (int j=-10; j<10; j++) m.remove(i+j*p);
		}

		t.addAll(m);

		/* Now all table entries are REMOVED. */

		int k = 0;
		for(int i=0; i<(p*f)/10; i++) {
			for (int j=0; j<10; j++) {
				k++;
				x = i+(r.nextInt() % 10)*p;
				if (m.add(x) != t.add(KEY2OBJ(x)))
					System.out.println("Error (" + seed + "): m and t differ on a key during torture-test insertion.");
			}
		}

		if (!m.equals(t)) System.out.println("Error (" + seed + "): !m.equals(t) after torture-test insertion");
		if (!t.equals(m)) System.out.println("Error (" + seed + "): !t.equals(m) after torture-test insertion");

		for(int i=0; i<(p*f)/10; i++) {
			for (int j=0; j<10; j++) {
				x = i+(r.nextInt() % 10)*p;
				if (m.remove(x) != t.remove(KEY2OBJ(x)))
					System.out.println("Error (" + seed + "): m and t differ on a key during torture-test removal.");
			}
		}

		if (!m.equals(t)) System.out.println("Error (" + seed + "): !m.equals(t) after torture-test removal");
		if (!t.equals(m)) System.out.println("Error (" + seed + "): !t.equals(m) after torture-test removal");

		if (!m.equals(m.clone())) System.out.println("Error (" + seed + "): !m.equals(m.clone()) after torture-test removal");
		if (!((OPEN_HASH_BIG_SET)m.clone()).equals(m)) System.out.println("Error (" + seed + "): !m.clone().equals(m) after torture-test removal");

		m.trim();

		if (!m.equals(t)) System.out.println("Error (" + seed + "): !m.equals(t) after trim()");
		if (!t.equals(m)) System.out.println("Error (" + seed + "): !t.equals(m) after trim()");

#endif

		System.out.println("Test OK");
		return;
	}


	public static void main(String args[]) {
		float f = Hash.DEFAULT_LOAD_FACTOR;
		int n  = Integer.parseInt(args[1]);
		if (args.length>2) f = Float.parseFloat(args[2]);
		if (args.length > 3) r = new java.util.Random(seed = Long.parseLong(args[3]));

		try {
			if ("speedTest".equals(args[0]) || "speedComp".equals(args[0])) speedTest(n, f, "speedComp".equals(args[0]));
			else if ("test".equals(args[0])) runTest(n, f);
		} catch(Throwable e) {
			e.printStackTrace(System.err);
			System.err.println("seed: " + seed);
		}
	}

#endif

}
