/*		 
 * Copyright (C) 2002-2014 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, 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;

	/** 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>/<code>f</code>.
	 *
	 * @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;
		
		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 );
	}

#if #keys(primitive)
	/** {@inheritDoc} */
	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

	/** {@inheritDoc} */
	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 );
	}


	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;
	}

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

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

	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 );
		}
	}
	 
	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 #keyclass(Object)
	/** Returns the element of this set that is equal to the given key, or <code>null</code>.
	 * @return the element of this set that is equal to the given key, or <code>null</code>.
	 */
	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.
	 *
	 * <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)}.
	 *
	 */

	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 extends KEY_ABSTRACT_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;

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

		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();
					wrapped.add( BIG_ARRAYS.get( key, pos ) );
				}

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

		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();
		}
	}

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


	/** A no-op for backward compatibility. The kind of tables implemented by
	 * this class never need rehashing.
	 *
	 * <P>If you need to reduce the table size to fit exactly
	 * this set, use {@link #trim()}.
	 *
	 * @return true.
	 * @see #trim()
	 * @deprecated A no-op.
	 */

	@Deprecated
	public boolean rehash() {
		return true;
	}

	/** 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 ) 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
	public int size() {
		return (int)Math.min( Integer.MAX_VALUE, size );
	}

	public long size64() {
		return size;
	}

	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.
	 */

	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()</code> 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.
	 */


	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 #keyclass(Byte) || #keyclass(Short) || #keyclass(Character)
		return (KEY_TYPE)(r.nextInt());
#elif #keys(primitive)
		return r.NEXT_KEY(); 
#elif #keyclass(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 test( 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 !#keyclass(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 #keyclass(Integer) || #keyclass(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.rehash();

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

#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] ) ) test(n, f);
		} catch( Throwable e ) {
			e.printStackTrace( System.err );
			System.err.println( "seed: " + seed );
		}
	}

#endif

}
