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The Trove library provides high speed regular and primitive
collections for Java.
///////////////////////////////////////////////////////////////////////////////
// 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 byte/int 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 TByteIntHash extends TPrimitiveHash {
static final long serialVersionUID = 1L;
/** the set of bytes */
public transient byte[] _set;
/**
* key that represents null
*
* NOTE: should not be modified after the Hash is created, but is
* not final because of Externalization
*
*/
protected byte 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 int no_entry_value;
protected boolean consumeFreeSlot;
/**
* Creates a new T#E#Hash instance with the default
* capacity and load factor.
*/
public TByteIntHash() {
super();
no_entry_key = ( byte ) 0;
no_entry_value = ( int ) 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 TByteIntHash( int initialCapacity ) {
super( initialCapacity );
no_entry_key = ( byte ) 0;
no_entry_value = ( int ) 0;
}
/**
* Creates a new TByteIntHash 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 TByteIntHash( int initialCapacity, float loadFactor ) {
super(initialCapacity, loadFactor);
no_entry_key = ( byte ) 0;
no_entry_value = ( int ) 0;
}
/**
* Creates a new TByteIntHash 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 TByteIntHash( int initialCapacity, float loadFactor,
byte no_entry_key, int 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 byte 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 int 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 byte[capacity];
return capacity;
}
/**
* Searches the set for val
*
* @param val an byte value
* @return a boolean value
*/
public boolean contains( byte val ) {
return index(val) >= 0;
}
/**
* Executes procedure for each key in the map.
*
* @param procedure a TByteProcedure value
* @return false if the loop over the set terminated because
* the procedure returned false for some value.
*/
public boolean forEach( TByteProcedure procedure ) {
byte[] states = _states;
byte[] 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 byte value
* @return the index of val or -1 if it isn't in the set.
*/
protected int index( byte key ) {
int hash, probe, index, length;
final byte[] states = _states;
final byte[] 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(byte 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 key an byte value
* @return an int value
*/
protected int insertKey( byte 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(byte 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, byte val) {
_set[index] = val; // insert value
_states[index] = FULL;
}
protected int XinsertKey( byte key ) {
int hash, probe, index, length;
final byte[] states = _states;
final byte[] 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.writeByte( no_entry_key );
// NO_ENTRY_VALUE
out.writeInt( 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.readByte();
// NO_ENTRY_VALUE
no_entry_value = in.readInt();
}
} // TByteIntHash