///////////////////////////////////////////////////////////////////////////////
// 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.impl.hash;
import gnu.trove.procedure.TCharProcedure;
import gnu.trove.impl.HashFunctions;
import gnu.trove.impl.Constants;
import java.util.Arrays;
//////////////////////////////////////////////////
// THIS IS A GENERATED CLASS. DO NOT HAND EDIT! //
//////////////////////////////////////////////////
/**
* An open addressed hashing implementation for char primitives.
*
* Created: Sun Nov 4 08:56:06 2001
*
* @author Eric D. Friedman, Rob Eden, Jeff Randall
* @version $Id: _E_Hash.template,v 1.1.2.6 2009/11/07 03:36:44 robeden Exp $
*/
abstract public class TCharHash extends TPrimitiveHash {
static final long serialVersionUID = 1L;
/** the set of chars */
public transient char[] _set;
/**
* value that represents null
*
* NOTE: should not be modified after the Hash is created, but is
* not final because of Externalization
*
*/
protected char no_entry_value;
/**
* Creates a new <code>TCharHash</code> instance with the default
* capacity and load factor.
*/
public TCharHash() {
super();
no_entry_value = Constants.DEFAULT_CHAR_NO_ENTRY_VALUE;
//noinspection RedundantCast
if ( no_entry_value != ( char ) 0 ) {
Arrays.fill( _set, no_entry_value );
}
}
/**
* Creates a new <code>TCharHash</code> instance whose capacity
* is the next highest prime above <tt>initialCapacity + 1</tt>
* unless that value is already prime.
*
* @param initialCapacity an <code>int</code> value
*/
public TCharHash( int initialCapacity ) {
super( initialCapacity );
no_entry_value = Constants.DEFAULT_CHAR_NO_ENTRY_VALUE;
//noinspection RedundantCast
if ( no_entry_value != ( char ) 0 ) {
Arrays.fill( _set, no_entry_value );
}
}
/**
* Creates a new <code>TCharHash</code> instance with a prime
* value at or near the specified capacity and load factor.
*
* @param initialCapacity used to find a prime capacity for the table.
* @param loadFactor used to calculate the threshold over which
* rehashing takes place.
*/
public TCharHash( int initialCapacity, float loadFactor ) {
super(initialCapacity, loadFactor);
no_entry_value = Constants.DEFAULT_CHAR_NO_ENTRY_VALUE;
//noinspection RedundantCast
if ( no_entry_value != ( char ) 0 ) {
Arrays.fill( _set, no_entry_value );
}
}
/**
* Creates a new <code>TCharHash</code> instance with a prime
* value at or near the specified capacity and load factor.
*
* @param initialCapacity used to find a prime capacity for the table.
* @param loadFactor used to calculate the threshold over which
* rehashing takes place.
* @param no_entry_value value that represents null
*/
public TCharHash( int initialCapacity, float loadFactor, char no_entry_value ) {
super(initialCapacity, loadFactor);
this.no_entry_value = no_entry_value;
//noinspection RedundantCast
if ( no_entry_value != ( char ) 0 ) {
Arrays.fill( _set, no_entry_value );
}
}
/**
* Returns the value that is used to represent null. The default
* value is generally zero, but can be changed during construction
* of the collection.
*
* @return the value that represents null
*/
public char getNoEntryValue() {
return no_entry_value;
}
/**
* initializes the hashtable to a prime capacity which is at least
* <tt>initialCapacity + 1</tt>.
*
* @param initialCapacity an <code>int</code> value
* @return the actual capacity chosen
*/
protected int setUp( int initialCapacity ) {
int capacity;
capacity = super.setUp( initialCapacity );
_set = new char[capacity];
return capacity;
}
/**
* Searches the set for <tt>val</tt>
*
* @param val an <code>char</code> value
* @return a <code>boolean</code> value
*/
public boolean contains( char val ) {
return index(val) >= 0;
}
/**
* Executes <tt>procedure</tt> for each element in the set.
*
* @param procedure a <code>TObjectProcedure</code> value
* @return false if the loop over the set terminated because
* the procedure returned false for some value.
*/
public boolean forEach( TCharProcedure procedure ) {
byte[] states = _states;
char[] set = _set;
for ( int i = set.length; i-- > 0; ) {
if ( states[i] == FULL && ! procedure.execute( set[i] ) ) {
return false;
}
}
return true;
}
/**
* Releases the element currently stored at <tt>index</tt>.
*
* @param index an <code>int</code> value
*/
protected void removeAt( int index ) {
_set[index] = no_entry_value;
super.removeAt( index );
}
/**
* Locates the index of <tt>val</tt>.
*
* @param val an <code>char</code> value
* @return the index of <tt>val</tt> or -1 if it isn't in the set.
*/
protected int index( char val ) {
int hash, probe, index, length;
final byte[] states = _states;
final char[] set = _set;
length = states.length;
hash = HashFunctions.hash( val ) & 0x7fffffff;
index = hash % length;
if ( states[index] != FREE &&
( states[index] == REMOVED || set[index] != val ) ) {
// see Knuth, p. 529
probe = 1 + ( hash % ( length - 2 ) );
do {
index -= probe;
if ( index < 0 ) {
index += length;
}
} while ( states[index] != FREE &&
( states[index] == REMOVED || set[index] != val ) );
}
return states[index] == FREE ? -1 : index;
}
/**
* Locates the index at which <tt>val</tt> can be inserted. if
* there is already a value equal()ing <tt>val</tt> in the set,
* returns that value as a negative integer.
*
* @param val an <code>char</code> value
* @return an <code>int</code> value
*/
protected int insertionIndex( char val ) {
int hash, probe, index, length;
final byte[] states = _states;
final char[] set = _set;
length = states.length;
hash = HashFunctions.hash( val ) & 0x7fffffff;
index = hash % length;
if ( states[index] == FREE ) {
return index; // empty, all done
} else if ( states[index] == FULL && set[index] == val ) {
return -index -1; // already stored
} else { // already FULL or REMOVED, must probe
// compute the double hash
probe = 1 + ( hash % ( length - 2 ) );
// if the slot we landed on is FULL (but not removed), probe
// until we find an empty slot, a REMOVED slot, or an element
// equal to the one we are trying to insert.
// finding an empty slot means that the value is not present
// and that we should use that slot as the insertion point;
// finding a REMOVED slot means that we need to keep searching,
// however we want to remember the offset of that REMOVED slot
// so we can reuse it in case a "new" insertion (i.e. not an update)
// is possible.
// finding a matching value means that we've found that our desired
// key is already in the table
if ( states[index] != REMOVED ) {
// starting at the natural offset, probe until we find an
// offset that isn't full.
do {
index -= probe;
if (index < 0) {
index += length;
}
} while ( states[index] == FULL && set[index] != val );
}
// if the index we found was removed: continue probing until we
// locate a free location or an element which equal()s the
// one we have.
if ( states[index] == REMOVED) {
int firstRemoved = index;
while ( states[index] != FREE &&
( states[index] == REMOVED || set[index] != val ) ) {
index -= probe;
if (index < 0) {
index += length;
}
}
return states[index] == FULL ? -index -1 : firstRemoved;
}
// if it's full, the key is already stored
return states[index] == FULL ? -index -1 : index;
}
}
} // TCharHash