gnu.trove.impl.hash.TShortFloatHash Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of core Show documentation
Show all versions of core Show documentation
High performance collections for Java
The newest version!
///////////////////////////////////////////////////////////////////////////////
// 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.*;
import gnu.trove.impl.HashFunctions;
import java.io.ObjectOutput;
import java.io.ObjectInput;
import java.io.IOException;
//////////////////////////////////////////////////
// THIS IS A GENERATED CLASS. DO NOT HAND EDIT! //
//////////////////////////////////////////////////
/**
* An open addressed hashing implementation for short/float primitive entries.
*
* Created: Sun Nov 4 08:56:06 2001
*
* @author Eric D. Friedman
* @author Rob Eden
* @author Jeff Randall
* @version $Id: _K__V_Hash.template,v 1.1.2.6 2009/11/07 03:36:44 robeden Exp $
*/
abstract public class TShortFloatHash extends TPrimitiveHash {
static final long serialVersionUID = 1L;
/** the set of shorts */
public transient short[] _set;
/**
* key that represents null
*
* NOTE: should not be modified after the Hash is created, but is
* not final because of Externalization
*
*/
protected short no_entry_key;
/**
* value that represents null
*
* NOTE: should not be modified after the Hash is created, but is
* not final because of Externalization
*
*/
protected float no_entry_value;
protected boolean consumeFreeSlot;
/**
* Creates a new T#E#Hash instance with the default
* capacity and load factor.
*/
public TShortFloatHash() {
super();
no_entry_key = ( short ) 0;
no_entry_value = ( float ) 0;
}
/**
* Creates a new T#E#Hash instance whose capacity
* is the next highest prime above initialCapacity + 1
* unless that value is already prime.
*
* @param initialCapacity an int value
*/
public TShortFloatHash( int initialCapacity ) {
super( initialCapacity );
no_entry_key = ( short ) 0;
no_entry_value = ( float ) 0;
}
/**
* Creates a new TShortFloatHash 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 TShortFloatHash( int initialCapacity, float loadFactor ) {
super(initialCapacity, loadFactor);
no_entry_key = ( short ) 0;
no_entry_value = ( float ) 0;
}
/**
* Creates a new TShortFloatHash 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 TShortFloatHash( int initialCapacity, float loadFactor,
short no_entry_key, float no_entry_value ) {
super(initialCapacity, loadFactor);
this.no_entry_key = no_entry_key;
this.no_entry_value = no_entry_value;
}
/**
* Returns the value that is used to represent null as a key. The default
* value is generally zero, but can be changed during construction
* of the collection.
*
* @return the value that represents null
*/
public short getNoEntryKey() {
return no_entry_key;
}
/**
* 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 float getNoEntryValue() {
return no_entry_value;
}
/**
* initializes the hashtable to a prime capacity which is at least
* initialCapacity + 1.
*
* @param initialCapacity an int value
* @return the actual capacity chosen
*/
protected int setUp( int initialCapacity ) {
int capacity;
capacity = super.setUp( initialCapacity );
_set = new short[capacity];
return capacity;
}
/**
* Searches the set for val
*
* @param val an short value
* @return a boolean value
*/
public boolean contains( short val ) {
return index(val) >= 0;
}
/**
* Executes procedure for each key in the map.
*
* @param procedure a TShortProcedure value
* @return false if the loop over the set terminated because
* the procedure returned false for some value.
*/
public boolean forEach( TShortProcedure procedure ) {
byte[] states = _states;
short[] 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 index.
*
* @param index an int value
*/
protected void removeAt( int index ) {
_set[index] = no_entry_key;
super.removeAt( index );
}
/**
* Locates the index of val.
*
* @param key an short value
* @return the index of val or -1 if it isn't in the set.
*/
protected int index( short key ) {
int hash, probe, index, length;
final byte[] states = _states;
final short[] set = _set;
length = states.length;
hash = HashFunctions.hash( key ) & 0x7fffffff;
index = hash % length;
byte state = states[index];
if (state == FREE)
return -1;
if (state == FULL && set[index] == key)
return index;
return indexRehashed(key, index, hash, state);
}
int indexRehashed(short key, int index, int hash, byte state) {
// see Knuth, p. 529
int length = _set.length;
int probe = 1 + (hash % (length - 2));
final int loopIndex = index;
do {
index -= probe;
if (index < 0) {
index += length;
}
state = _states[index];
//
if (state == FREE)
return -1;
//
if (key == _set[index] && state != REMOVED)
return index;
} while (index != loopIndex);
return -1;
}
/**
* Locates the index at which val can be inserted. if
* there is already a value equal()ing val in the set,
* returns that value as a negative integer.
*
* @param val an short value
* @return an int value
*/
protected int insertKey( short val ) {
int hash, index;
hash = HashFunctions.hash(val) & 0x7fffffff;
index = hash % _states.length;
byte state = _states[index];
consumeFreeSlot = false;
if (state == FREE) {
consumeFreeSlot = true;
insertKeyAt(index, val);
return index; // empty, all done
}
if (state == FULL && _set[index] == val) {
return -index - 1; // already stored
}
// already FULL or REMOVED, must probe
return insertKeyRehash(val, index, hash, state);
}
int insertKeyRehash(short val, int index, int hash, byte state) {
// compute the double hash
final int length = _set.length;
int probe = 1 + (hash % (length - 2));
final int loopIndex = index;
int firstRemoved = -1;
/**
* Look until FREE slot or we start to loop
*/
do {
// Identify first removed slot
if (state == REMOVED && firstRemoved == -1)
firstRemoved = index;
index -= probe;
if (index < 0) {
index += length;
}
state = _states[index];
// A FREE slot stops the search
if (state == FREE) {
if (firstRemoved != -1) {
insertKeyAt(firstRemoved, val);
return firstRemoved;
} else {
consumeFreeSlot = true;
insertKeyAt(index, val);
return index;
}
}
if (state == FULL && _set[index] == val) {
return -index - 1;
}
// Detect loop
} while (index != loopIndex);
// We inspected all reachable slots and did not find a FREE one
// If we found a REMOVED slot we return the first one found
if (firstRemoved != -1) {
insertKeyAt(firstRemoved, val);
return firstRemoved;
}
// Can a resizing strategy be found that resizes the set?
throw new IllegalStateException("No free or removed slots available. Key set full?!!");
}
void insertKeyAt(int index, short val) {
_set[index] = val; // insert value
_states[index] = FULL;
}
protected int XinsertKey( short key ) {
int hash, probe, index, length;
final byte[] states = _states;
final short[] set = _set;
length = states.length;
hash = HashFunctions.hash( key ) & 0x7fffffff;
index = hash % length;
byte state = states[index];
consumeFreeSlot = false;
if ( state == FREE ) {
consumeFreeSlot = true;
set[index] = key;
states[index] = FULL;
return index; // empty, all done
} else if ( state == FULL && set[index] == key ) {
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 ( state != REMOVED ) {
// starting at the natural offset, probe until we find an
// offset that isn't full.
do {
index -= probe;
if (index < 0) {
index += length;
}
state = states[index];
} while ( state == FULL && set[index] != key );
}
// 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 ( state == REMOVED) {
int firstRemoved = index;
while ( state != FREE && ( state == REMOVED || set[index] != key ) ) {
index -= probe;
if (index < 0) {
index += length;
}
state = states[index];
}
if (state == FULL) {
return -index -1;
} else {
set[index] = key;
states[index] = FULL;
return firstRemoved;
}
}
// if it's full, the key is already stored
if (state == FULL) {
return -index -1;
} else {
consumeFreeSlot = true;
set[index] = key;
states[index] = FULL;
return index;
}
}
}
/** {@inheritDoc} */
public void writeExternal( ObjectOutput out ) throws IOException {
// VERSION
out.writeByte( 0 );
// SUPER
super.writeExternal( out );
// NO_ENTRY_KEY
out.writeShort( no_entry_key );
// NO_ENTRY_VALUE
out.writeFloat( no_entry_value );
}
/** {@inheritDoc} */
public void readExternal( ObjectInput in ) throws IOException, ClassNotFoundException {
// VERSION
in.readByte();
// SUPER
super.readExternal( in );
// NO_ENTRY_KEY
no_entry_key = in.readShort();
// NO_ENTRY_VALUE
no_entry_value = in.readFloat();
}
} // TShortFloatHash
© 2015 - 2024 Weber Informatics LLC | Privacy Policy