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///////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2001, Eric D. Friedman All Rights Reserved.
// Copyright (c) 2009, Rob Eden All Rights Reserved.
// Copyright (c) 2009, Jeff Randall All Rights Reserved.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
///////////////////////////////////////////////////////////////////////////////

package gnu.trove.set.hash;

import gnu.trove.strategy.HashingStrategy;
import gnu.trove.impl.HashFunctions;
import gnu.trove.impl.hash.TCustomObjectHash;
import gnu.trove.iterator.hash.TObjectHashIterator;
import gnu.trove.procedure.TObjectProcedure;
import gnu.trove.procedure.array.ToObjectArrayProceedure;

import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.lang.reflect.Array;
import java.util.Arrays;
import java.util.Collection;
import java.util.Iterator;
import java.util.Set;


/**
 * An implementation of the Set interface that uses an
 * open-addressed hash table to store its contents.
 *
 * @author Rob Eden
 */
public class TCustomHashSet extends TCustomObjectHash
	implements Set, Iterable, Externalizable {

    static final long serialVersionUID = 1L;


	/** FOR EXTERNALIZATION ONLY!!! */
	public TCustomHashSet() {}


    /**
     * Creates a new THashSet instance with the default
     * capacity and load factor.
     */
    public TCustomHashSet( HashingStrategy strategy ) {
        super( strategy );
    }


    /**
     * Creates a new THashSet instance with a prime
     * capacity equal to or greater than initialCapacity and
     * with the default load factor.
     *
     * @param initialCapacity an int value
     */
    public TCustomHashSet( HashingStrategy strategy, int initialCapacity ) {
        super( strategy, initialCapacity );
    }


    /**
     * Creates a new THashSet instance with a prime
     * capacity equal to or greater than initialCapacity and
     * with the specified load factor.
     *
     * @param initialCapacity an int value
     * @param loadFactor      a float value
     */
    public TCustomHashSet( HashingStrategy strategy, int initialCapacity,
	    float loadFactor ) {

        super( strategy, initialCapacity, loadFactor );
    }


    /**
     * Creates a new THashSet instance containing the
     * elements of collection.
     *
     * @param collection a Collection value
     */
    public TCustomHashSet( HashingStrategy strategy,
	    Collection collection ) {

        this( strategy, collection.size() );
        addAll( collection );
    }


    /**
     * Inserts a value into the set.
     *
     * @param obj an Object value
     * @return true if the set was modified by the add operation
     */
    public boolean add( E obj ) {
        int index = insertKey( obj );

        if ( index < 0 ) {
            return false;       // already present in set, nothing to add
        }

        postInsertHook( consumeFreeSlot );
        return true;            // yes, we added something
    }


    @SuppressWarnings({"SimplifiableIfStatement"})
    public boolean equals( Object other ) {
        if ( !( other instanceof Set ) ) {
            return false;
        }
        Set that = (Set) other;
        if ( that.size() != this.size() ) {
            return false;
        }
        return containsAll( that );
    }


    public int hashCode() {
        HashProcedure p = new HashProcedure();
        forEach( p );
        return p.getHashCode();
    }


    private final class HashProcedure implements TObjectProcedure {
        private int h = 0;

        public int getHashCode() {
            return h;
        }

        public final boolean execute( E key ) {
            h += HashFunctions.hash( key );
            return true;
        }
    }


    /**
     * Expands the set to accommodate new values.
     *
     * @param newCapacity an int value
     */
    @SuppressWarnings({"unchecked"})
    protected void rehash( int newCapacity ) {
        int oldCapacity = _set.length;
        int oldSize = size();
        Object oldSet[] = _set;

        _set = new Object[newCapacity];
        Arrays.fill( _set, FREE );

        for ( int i = oldCapacity; i-- > 0; ) {
            E o = (E) oldSet[i];
            if ( o != FREE && o != REMOVED ) {
                int index = insertKey( o );
                if ( index < 0 ) { // everyone pays for this because some people can't RTFM
                    throwObjectContractViolation( _set[( -index - 1 )], o, size(), oldSize, oldSet);
                }
            }
        }
    }


    /**
     * Returns a new array containing the objects in the set.
     *
     * @return an Object[] value
     */
    @SuppressWarnings({"unchecked"})
    public Object[] toArray() {
        Object[] result = new Object[size()];
        forEach( new ToObjectArrayProceedure( result ) );
        return result;
    }


    /**
     * Returns a typed array of the objects in the set.
     *
     * @param a an Object[] value
     * @return an Object[] value
     */
    @SuppressWarnings({"unchecked"})
    public  T[] toArray( T[] a ) {
        int size = size();
        if ( a.length < size ) {
            a = (T[]) Array.newInstance( a.getClass().getComponentType(), size );
        }

        forEach( new ToObjectArrayProceedure( a ) );

        // If this collection fits in the specified array with room to
        // spare (i.e., the array has more elements than this
        // collection), the element in the array immediately following
        // the end of the collection is set to null. This is useful in
        // determining the length of this collection only if the
        // caller knows that this collection does not contain any null
        // elements.)

        if ( a.length > size ) {
            a[size] = null;
        }

        return a;
    }


    /** Empties the set. */
    public void clear() {
        super.clear();

        Arrays.fill( _set, 0, _set.length, FREE );
    }


    /**
     * Removes obj from the set.
     *
     * @param obj an Object value
     * @return true if the set was modified by the remove operation.
     */
    @SuppressWarnings({"unchecked"})
    public boolean remove( Object obj ) {
        int index = index( obj );
        if ( index >= 0 ) {
            removeAt( index );
            return true;
        }
        return false;
    }


    /**
     * Creates an iterator over the values of the set.  The iterator
     * supports element deletion.
     *
     * @return an Iterator value
     */
    @SuppressWarnings({"unchecked"})
    public TObjectHashIterator iterator() {
        return new TObjectHashIterator( this );
    }


    /**
     * Tests the set to determine if all of the elements in
     * collection are present.
     *
     * @param collection a Collection value
     * @return true if all elements were present in the set.
     */
    @SuppressWarnings("ForLoopReplaceableByForEach")
    public boolean containsAll( Collection collection ) {
        for ( Iterator i = collection.iterator(); i.hasNext(); ) {
            if ( !contains( i.next() ) ) {
                return false;
            }
        }
        return true;
    }


    /**
     * Adds all of the elements in collection to the set.
     *
     * @param collection a Collection value
     * @return true if the set was modified by the add all operation.
     */
    public boolean addAll( Collection collection ) {
        boolean changed = false;
        int size = collection.size();

        ensureCapacity( size );
        Iterator it = collection.iterator();
        while ( size-- > 0 ) {
            if ( add( it.next() ) ) {
                changed = true;
            }
        }
        return changed;
    }


    /**
     * Removes all of the elements in collection from the set.
     *
     * @param collection a Collection value
     * @return true if the set was modified by the remove all operation.
     */
    public boolean removeAll( Collection collection ) {
        boolean changed = false;
        int size = collection.size();
        Iterator it;

        it = collection.iterator();
        while ( size-- > 0 ) {
            if ( remove( it.next() ) ) {
                changed = true;
            }
        }
        return changed;
    }


    /**
     * Removes any values in the set which are not contained in
     * collection.
     *
     * @param collection a Collection value
     * @return true if the set was modified by the retain all operation
     */
    @SuppressWarnings({"SuspiciousMethodCalls"})
    public boolean retainAll( Collection collection ) {
        boolean changed = false;
        int size = size();
        Iterator it = iterator();
        while ( size-- > 0 ) {
            if ( !collection.contains( it.next() ) ) {
                it.remove();
                changed = true;
            }
        }
        return changed;
    }


    public String toString() {
        final StringBuilder buf = new StringBuilder( "{" );
        forEach( new TObjectProcedure() {
            private boolean first = true;


            public boolean execute( Object value ) {
                if ( first ) {
                    first = false;
                } else {
                    buf.append( ", " );
                }

                buf.append( value );
                return true;
            }
        } );
        buf.append( "}" );
        return buf.toString();
    }


    public void writeExternal( ObjectOutput out ) throws IOException {
        // VERSION
        out.writeByte( 1 );

        // NOTE: Super was not written in version 0
        super.writeExternal( out );

        // NUMBER OF ENTRIES
        out.writeInt( _size );

        // ENTRIES
        for ( int i = _set.length; i-- > 0; ) {
            if ( _set[i] != REMOVED && _set[i] != FREE ) {
                out.writeObject( _set[i] );
            }
        }
    }


    @SuppressWarnings({"unchecked"})
    public void readExternal( ObjectInput in )
            throws IOException, ClassNotFoundException {

        // VERSION
        byte version = in.readByte();

        // NOTE: super was not written in version 0
        if ( version != 0 ) {
            super.readExternal( in );
        }

        // NUMBER OF ENTRIES
        int size = in.readInt();
        setUp( size );

        // ENTRIES
        while ( size-- > 0 ) {
            E val = (E) in.readObject();
            add( val );
        }
    }
}