src.it.unimi.dsi.fastutil.objects.ObjectOpenHashBigSet Maven / Gradle / Ivy
/* Generic definitions */
/* Assertions (useful to generate conditional code) */
/* Current type and class (and size, if applicable) */
/* Value methods */
/* Interfaces (keys) */
/* Interfaces (values) */
/* Abstract implementations (keys) */
/* Abstract implementations (values) */
/* Static containers (keys) */
/* Static containers (values) */
/* Implementations */
/* Synchronized wrappers */
/* Unmodifiable wrappers */
/* Other wrappers */
/* Methods (keys) */
/* Methods (values) */
/* Methods (keys/values) */
/* Methods that have special names depending on keys (but the special names depend on values) */
/* Equality */
/* Object/Reference-only definitions (keys) */
/* Object/Reference-only definitions (values) */
/*
* Copyright (C) 2002-2013 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 it.unimi.dsi.fastutil.objects;
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 it.unimi.dsi.fastutil.booleans.BooleanBigArrays;
import static it.unimi.dsi.fastutil.HashCommon.bigArraySize;
import static it.unimi.dsi.fastutil.HashCommon.maxFill;
import java.util.Collection;
import java.util.NoSuchElementException;
/** A type-specific hash big set with with a fast, small-footprint implementation.
*
* 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 is
* backed by a {@linkplain it.unimi.dsi.fastutil.BigArrays big array} and is
* enlarged as needed by doubling its size when new entries are created, but it is never made
* smaller (even on a {@link #clear()}). A family of {@linkplain #trim(long) trimming
* method} lets you control the size of the table; this is particularly useful
* if you reuse instances of this class.
*
*
The methods of this class are about 30% slower than those of the corresponding non-big set.
*
* @see Hash
* @see HashCommon
*/
public class ObjectOpenHashBigSet extends AbstractObjectSet implements java.io.Serializable, Cloneable, Hash, Size64 {
private static final long serialVersionUID = 0L;
private static final boolean ASSERTS = false;
/** The big array of keys. */
protected transient K[][] key;
/** The big array telling whether a position is used. */
protected transient boolean[][] used;
/** The acceptable load factor. */
protected final float f;
/** 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 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;
/** 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.
*
* The actual table size will be the least power of two greater than expected/f.
*
* @param expected the expected number of elements in the set.
* @param f the load factor.
*/
@SuppressWarnings("unchecked")
public ObjectOpenHashBigSet( 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 = (K[][]) ObjectBigArrays.newBigArray( n );
used = BooleanBigArrays.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 ObjectOpenHashBigSet( 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 ObjectOpenHashBigSet() {
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 ObjectOpenHashBigSet( final Collection 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 ObjectOpenHashBigSet( final Collection 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 ObjectOpenHashBigSet( final ObjectCollection 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 ObjectOpenHashBigSet( final ObjectCollection 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 ObjectOpenHashBigSet( final ObjectIterator i, final float f ) {
this( DEFAULT_INITIAL_SIZE, f );
while( i.hasNext() ) add( i.next() );
}
/** 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 ObjectOpenHashBigSet( final ObjectIterator i ) {
this( i, DEFAULT_LOAD_FACTOR );
}
/** 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 ObjectOpenHashBigSet( final K[] a, final int offset, final int length, final float f ) {
this( length < 0 ? 0 : length, f );
ObjectArrays.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 ObjectOpenHashBigSet( final K[] 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 ObjectOpenHashBigSet( final K[] 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 ObjectOpenHashBigSet( final K[] a ) {
this( a, DEFAULT_LOAD_FACTOR );
}
public boolean add( final K k ) {
final long h = ( (k) == null ? 0x810879608e4259ccL : it.unimi.dsi.fastutil.HashCommon.murmurHash3( (long)(k).hashCode() ) );
// The starting point.
int displ = (int)( h & segmentMask );
int base = (int)( ( h & mask ) >>> BigArrays.SEGMENT_SHIFT );
// There's always an unused entry.
while( used[ base ][ displ ] ) {
if ( ( (key[ base ][ displ ]) == null ? (k) == null : (key[ base ][ displ ]).equals(k) ) ) return false;
base = ( base + ( ( displ = ( displ + 1 ) & segmentMask ) == 0 ? 1 : 0 ) ) & baseMask;
}
used[ base ][ displ ] = true;
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.
* @return the position cleared by the shifting process.
*/
protected final long shiftKeys( long pos ) {
// Shift entries with the same hash.
long last, slot;
/*
for( int i = 0; i < 10; i++ ) System.err.print( key[ ( t + i ) & mask ] + "(" + (avalanche( (long)KEY2INT( key[ ( t + i ) & mask ] ) ) & mask) + "; " + used[ ( t + i ) & mask ] + ") ");
System.err.println();
*/
for(;;) {
pos = ( ( last = pos ) + 1 ) & mask;
while( BooleanBigArrays.get( used, pos ) ) {
slot = ( (ObjectBigArrays.get( key, pos )) == null ? 0x810879608e4259ccL : it.unimi.dsi.fastutil.HashCommon.murmurHash3( (long)(ObjectBigArrays.get( key, pos )).hashCode() ) ) & mask;
if ( last <= pos ? last >= slot || slot > pos : last >= slot && slot > pos ) break;
pos = ( pos + 1 ) & mask;
}
if ( ! BooleanBigArrays.get( used, pos ) ) break;
ObjectBigArrays.set( key, last, ObjectBigArrays.get( key, pos ) );
}
BooleanBigArrays.set( used, last, false );
ObjectBigArrays.set( key, last, null );
return last;
}
@SuppressWarnings("unchecked")
public boolean remove( final Object k ) {
final long h = ( (k) == null ? 0x810879608e4259ccL : it.unimi.dsi.fastutil.HashCommon.murmurHash3( (long)(k).hashCode() ) );
// The starting point.
int displ = (int)( h & segmentMask );
int base = (int)( ( h & mask ) >>> BigArrays.SEGMENT_SHIFT );
// There's always an unused entry.
while( used[ base ][ displ ] ) {
if ( ( (key[ base ][ displ ]) == null ? (k) == null : (key[ base ][ displ ]).equals(k) ) ) {
size--;
shiftKeys( base * (long)BigArrays.SEGMENT_SIZE + displ );
if ( ASSERTS ) checkTable();
return true;
}
base = ( base + ( ( displ = ( displ + 1 ) & segmentMask ) == 0 ? 1 : 0 ) ) & baseMask;
}
return false;
}
@SuppressWarnings("unchecked")
public boolean contains( final Object k ) {
final long h = ( (k) == null ? 0x810879608e4259ccL : it.unimi.dsi.fastutil.HashCommon.murmurHash3( (long)(k).hashCode() ) );
// The starting point.
int displ = (int)( h & segmentMask );
int base = (int)( ( h & mask ) >>> BigArrays.SEGMENT_SHIFT );
// There's always an unused entry.
while( used[ base ][ displ ] ) {
if ( ( (key[ base ][ displ ]) == null ? (k) == null : (key[ base ][ displ ]).equals(k) ) ) return true;
base = ( base + ( ( displ = ( displ + 1 ) & segmentMask ) == 0 ? 1 : 0 ) ) & baseMask;
}
return false;
}
/** Returns the element of this set that is equal to the given key, or null.
* @return the element of this set that is equal to the given key, or null.
*/
public K get( final Object k ) {
final long h = ( (k) == null ? 0x810879608e4259ccL : it.unimi.dsi.fastutil.HashCommon.murmurHash3( (long)(k).hashCode() ) );
// The starting point.
int displ = (int)( h & segmentMask );
int base = (int)( ( h & mask ) >>> BigArrays.SEGMENT_SHIFT );
// There's always an unused entry.
while( used[ base ][ displ ] ) {
if ( ( (key[ base ][ displ ]) == null ? (k) == null : (key[ base ][ displ ]).equals(k) ) ) return key[ base ][ displ ];
base = ( base + ( ( displ = ( displ + 1 ) & segmentMask ) == 0 ? 1 : 0 ) ) & baseMask;
}
return null;
}
/* Removes all elements from this set.
*
* 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;
BooleanBigArrays.fill( used, false );
ObjectBigArrays.fill( key, null );
}
/** An iterator over a hash big set. */
private class SetIterator extends AbstractObjectIterator {
/** The base of the next entry to be returned, if positive or zero. If negative, the next entry to be
returned, if any, is that of index -base -2 from the {@link #wrapped} list. */
int base;
/** The displacement of the next entry to be returned. */
int displ;
/** The base of the last entry that has been returned. It is -1 if either
we did not return an entry yet, or the last returned entry has been removed. */
int lastBase;
/** The displacement of the last entry that has been returned. It is undefined if either
we did not return an entry yet, or the last returned entry has been removed. */
int lastDispl;
/** A downward counter measuring how many entries must still be returned. */
long c = size;
/** A lazily allocated list containing elements that have wrapped around the table because of removals; such elements
would not be enumerated (other elements would be usually enumerated twice in their place). */
ObjectArrayList wrapped;
{
base = key.length;
lastBase = -1;
final boolean used[][] = ObjectOpenHashBigSet.this.used;
if ( c != 0 ) do
if ( displ-- == 0 ) {
base--;
displ = (int)mask;
}
while( ! used[ base ][ displ ] );
}
public boolean hasNext() {
return c != 0;
}
public K next() {
if ( ! hasNext() ) throw new NoSuchElementException();
c--;
// We are just enumerating elements from the wrapped list.
if ( base < 0 ) return wrapped.get( - ( lastBase = --base ) - 2 );
final K retVal = key[ lastBase = base ][ lastDispl = displ ];
if ( c != 0 ) {
final boolean used[][] = ObjectOpenHashBigSet.this.used;
do
if ( displ-- == 0 ) {
if ( base-- == 0 ) break;
displ = (int)mask;
}
while( ! used[ base ][ displ ] );
// When here base < 0 there are no more elements to be enumerated by scanning, but wrapped might be nonempty.
}
return retVal;
}
/** Shifts left entries with the specified hash code, starting at the specified position,
* and empties the resulting free entry. If any entry wraps around the table, instantiates
* lazily {@link #wrapped} and stores the entry.
*
* @param pos a starting position.
* @return the position cleared by the shifting process.
*/
protected final long shiftKeys( long pos ) {
// Shift entries with the same hash.
long last, slot;
/*
for( int i = 0; i < 10; i++ ) System.err.print( key[ ( t + i ) & mask ] + "(" + (avalanche( (long)KEY2INT( key[ ( t + i ) & mask ] ) ) & mask) + "; " + used[ ( t + i ) & mask ] + ") ");
System.err.println();
*/
for(;;) {
pos = ( ( last = pos ) + 1 ) & mask;
while( BooleanBigArrays.get( used, pos ) ) {
slot = ( (ObjectBigArrays.get( key, pos )) == null ? 0x810879608e4259ccL : it.unimi.dsi.fastutil.HashCommon.murmurHash3( (long)(ObjectBigArrays.get( key, pos )).hashCode() ) ) & mask;
if ( last <= pos ? last >= slot || slot > pos : last >= slot && slot > pos ) break;
pos = ( pos + 1 ) & mask;
}
if ( ! BooleanBigArrays.get( used, pos ) ) break;
if ( pos < last ) {
// Wrapped entry.
if ( wrapped == null ) wrapped = new ObjectArrayList ();
wrapped.add( ObjectBigArrays.get( key, pos ) );
}
ObjectBigArrays.set( key, last, ObjectBigArrays.get( key, pos ) );
}
BooleanBigArrays.set( used, last, false );
ObjectBigArrays.set( key, last, null );
return last;
}
@SuppressWarnings("unchecked")
public void remove() {
if ( lastBase == -1 ) throw new IllegalStateException();
if ( base < -1 ) {
// We're removing wrapped entries.
ObjectOpenHashBigSet.this.remove( wrapped.set( - base - 2, null ) );
lastBase = -1;
return;
}
size--;
if ( shiftKeys( lastBase * (long)BigArrays.SEGMENT_SIZE + lastDispl ) == base * (long)BigArrays.SEGMENT_SIZE + displ && c > 0 ) {
c++;
next();
}
lastBase = -1; // You can no longer remove this entry.
if ( ASSERTS ) checkTable();
}
}
public ObjectIterator iterator() {
return new SetIterator();
}
/** A no-op for backward compatibility. The kind of tables implemented by
* this class never need rehashing.
*
* 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.
*
*
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.
*
*
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.
*
*
Let N be the smallest table size that can hold
* max(n,{@link #size64()}) entries, still satisfying the load factor. If the current
* table size is smaller than or equal to N, this method does
* nothing. Otherwise, it rehashes this set in a table of size
* N.
*
*
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.
*
*
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
*/
@SuppressWarnings("unchecked")
protected void rehash( final long newN ) {
final boolean used[][] = this.used;
final K key[][] = this.key;
final boolean newUsed[][] = BooleanBigArrays.newBigArray( newN );
final K newKey[][] = (K[][]) ObjectBigArrays.newBigArray( newN );
final long newMask = newN - 1;
final int newSegmentMask = newKey[ 0 ].length - 1;
final int newBaseMask = newKey.length - 1;
int base = 0, displ = 0;
long h;
K k;
for( long i = size; i-- != 0; ) {
while( ! used[ base ][ displ ] ) base = ( base + ( ( displ = ( displ + 1 ) & segmentMask ) == 0 ? 1 : 0 ) );
k = key[ base ][ displ ];
h = ( (k) == null ? 0x810879608e4259ccL : it.unimi.dsi.fastutil.HashCommon.murmurHash3( (long)(k).hashCode() ) );
// The starting point.
int d = (int)( h & newSegmentMask );
int b = (int)( ( h & newMask ) >>> BigArrays.SEGMENT_SHIFT );
while( newUsed[ b ][ d ] ) b = ( b + ( ( d = ( d + 1 ) & newSegmentMask ) == 0 ? 1 : 0 ) ) & newBaseMask;
newUsed[ b ][ d ] = true;
newKey[ b ][ d ] = k;
base = ( base + ( ( displ = ( displ + 1 ) & segmentMask ) == 0 ? 1 : 0 ) );
}
this.n = newN;
this.key = newKey;
this.used = newUsed;
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.
*
*
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.
*/
@SuppressWarnings("unchecked")
public ObjectOpenHashBigSet clone() {
ObjectOpenHashBigSet c;
try {
c = (ObjectOpenHashBigSet )super.clone();
}
catch(CloneNotSupportedException cantHappen) {
throw new InternalError();
}
c.key = ObjectBigArrays.copy( key );
c.used = BooleanBigArrays.copy( used );
return c;
}
/** Returns a hash code for this set.
*
* This method overrides the generic method provided by the superclass.
* Since equals() 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 boolean used[][] = this.used;
final K key[][] = this.key;
int h = 0;
int base = 0, displ = 0;
for( long j = size; j-- != 0; ) {
while( ! used[ base ][ displ ] ) base = ( base + ( ( displ = ( displ + 1 ) & segmentMask ) == 0 ? 1 : 0 ) );
if ( this != key[ base ][ displ ] )
h += ( (key[ base ][ displ ]) == null ? 0 : (key[ base ][ displ ]).hashCode() );
base = ( base + ( ( displ = ( displ + 1 ) & segmentMask ) == 0 ? 1 : 0 ) );
}
return h;
}
private void writeObject(java.io.ObjectOutputStream s) throws java.io.IOException {
final ObjectIterator i = iterator();
s.defaultWriteObject();
for( long j = size; j-- != 0; ) s.writeObject( i.next() );
}
@SuppressWarnings("unchecked")
private void readObject(java.io.ObjectInputStream s) throws java.io.IOException, ClassNotFoundException {
s.defaultReadObject();
n = bigArraySize( size, f );
maxFill = maxFill( n, f );
final K[][] key = this.key = (K[][]) ObjectBigArrays.newBigArray( n );
final boolean used[][] = this.used = BooleanBigArrays.newBigArray( n );
initMasks();
long h;
K k;
int base, displ;
for( long i = size; i-- != 0; ) {
k = (K) s.readObject();
h = ( (k) == null ? 0x810879608e4259ccL : it.unimi.dsi.fastutil.HashCommon.murmurHash3( (long)(k).hashCode() ) );
base = (int)( ( h & mask ) >>> BigArrays.SEGMENT_SHIFT );
displ = (int)( h & segmentMask );
while( used[ base ][ displ ] ) base = ( base + ( ( displ = ( displ + 1 ) & segmentMask ) == 0 ? 1 : 0 ) ) & baseMask;
used[ base ][ displ ] = true;
key[ base ][ displ ] = k;
}
if ( ASSERTS ) checkTable();
}
private void checkTable() {}
}