All Downloads are FREE. Search and download functionalities are using the official Maven repository.

src.it.unimi.dsi.fastutil.doubles.Double2IntOpenCustomHashMap Maven / Gradle / Ivy

The newest version!
/* 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) */
/* Primitive-type-only definitions (keys) */
/* Object/Reference-only definitions (values) */
/* Primitive-type-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.doubles;
import it.unimi.dsi.fastutil.Hash;
import it.unimi.dsi.fastutil.HashCommon;
import it.unimi.dsi.fastutil.booleans.BooleanArrays;
import static it.unimi.dsi.fastutil.HashCommon.arraySize;
import static it.unimi.dsi.fastutil.HashCommon.maxFill;
import java.util.Map;
import java.util.NoSuchElementException;
import it.unimi.dsi.fastutil.ints.IntCollection;
import it.unimi.dsi.fastutil.ints.AbstractIntCollection;
import it.unimi.dsi.fastutil.ints.IntIterator;
import it.unimi.dsi.fastutil.objects.AbstractObjectSet;
import it.unimi.dsi.fastutil.objects.ObjectIterator;
/** A type-specific hash map with a fast, small-footprint implementation whose {@linkplain it.unimi.dsi.fastutil.Hash.Strategy hashing strategy}
 * is specified at creation time.
 *
 * 

Instances of this class use a hash table to represent a map. The table 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() trimming * methods} lets you control the size of the table; this is particularly useful * if you reuse instances of this class. * *

Warning: The implementation of this class has significantly * changed in fastutil 6.1.0. Please read the * comments about this issue in the section “Faster Hash Tables” of the overview. * * @see Hash * @see HashCommon */ public class Double2IntOpenCustomHashMap extends AbstractDouble2IntMap implements java.io.Serializable, Cloneable, Hash { private static final long serialVersionUID = 0L; private static final boolean ASSERTS = false; /** The array of keys. */ protected transient double key[]; /** The array of values. */ protected transient int value[]; /** The array telling whether a position is used. */ protected transient boolean used[]; /** The acceptable load factor. */ protected final float f; /** The current table size. */ protected transient int n; /** Threshold after which we rehash. It must be the table size times {@link #f}. */ protected transient int maxFill; /** The mask for wrapping a position counter. */ protected transient int mask; /** Number of entries in the set. */ protected int size; /** Cached set of entries. */ protected transient volatile FastEntrySet entries; /** Cached set of keys. */ protected transient volatile DoubleSet keys; /** Cached collection of values. */ protected transient volatile IntCollection values; /** The hash strategy of this custom map. */ protected it.unimi.dsi.fastutil.doubles.DoubleHash.Strategy strategy; /** Creates a new hash map. * *

The actual table size will be the least power of two greater than expected/f. * * @param expected the expected number of elements in the hash set. * @param f the load factor. * @param strategy the strategy. */ @SuppressWarnings("unchecked") public Double2IntOpenCustomHashMap( final int expected, final float f, final it.unimi.dsi.fastutil.doubles.DoubleHash.Strategy strategy ) { this.strategy = strategy; if ( f <= 0 || f > 1 ) throw new IllegalArgumentException( "Load factor must be greater than 0 and smaller than or equal to 1" ); if ( expected < 0 ) throw new IllegalArgumentException( "The expected number of elements must be nonnegative" ); this.f = f; n = arraySize( expected, f ); mask = n - 1; maxFill = maxFill( n, f ); key = new double[ n ]; value = new int[ n ]; used = new boolean[ n ]; } /** Creates a new hash map with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor. * * @param expected the expected number of elements in the hash map. * @param strategy the strategy. */ public Double2IntOpenCustomHashMap( final int expected, final it.unimi.dsi.fastutil.doubles.DoubleHash.Strategy strategy ) { this( expected, DEFAULT_LOAD_FACTOR, strategy ); } /** Creates a new hash map with initial expected {@link Hash#DEFAULT_INITIAL_SIZE} entries * and {@link Hash#DEFAULT_LOAD_FACTOR} as load factor. * @param strategy the strategy. */ public Double2IntOpenCustomHashMap( final it.unimi.dsi.fastutil.doubles.DoubleHash.Strategy strategy ) { this( DEFAULT_INITIAL_SIZE, DEFAULT_LOAD_FACTOR, strategy ); } /** Creates a new hash map copying a given one. * * @param m a {@link Map} to be copied into the new hash map. * @param f the load factor. * @param strategy the strategy. */ public Double2IntOpenCustomHashMap( final Map m, final float f, final it.unimi.dsi.fastutil.doubles.DoubleHash.Strategy strategy ) { this( m.size(), f, strategy ); putAll( m ); } /** Creates a new hash map with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor copying a given one. * * @param m a {@link Map} to be copied into the new hash map. * @param strategy the strategy. */ public Double2IntOpenCustomHashMap( final Map m, final it.unimi.dsi.fastutil.doubles.DoubleHash.Strategy strategy ) { this( m, DEFAULT_LOAD_FACTOR, strategy ); } /** Creates a new hash map copying a given type-specific one. * * @param m a type-specific map to be copied into the new hash map. * @param f the load factor. * @param strategy the strategy. */ public Double2IntOpenCustomHashMap( final Double2IntMap m, final float f, final it.unimi.dsi.fastutil.doubles.DoubleHash.Strategy strategy ) { this( m.size(), f, strategy ); putAll( m ); } /** Creates a new hash map with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor copying a given type-specific one. * * @param m a type-specific map to be copied into the new hash map. * @param strategy the strategy. */ public Double2IntOpenCustomHashMap( final Double2IntMap m, final it.unimi.dsi.fastutil.doubles.DoubleHash.Strategy strategy ) { this( m, DEFAULT_LOAD_FACTOR, strategy ); } /** Creates a new hash map using the elements of two parallel arrays. * * @param k the array of keys of the new hash map. * @param v the array of corresponding values in the new hash map. * @param f the load factor. * @param strategy the strategy. * @throws IllegalArgumentException if k and v have different lengths. */ public Double2IntOpenCustomHashMap( final double[] k, final int v[], final float f, final it.unimi.dsi.fastutil.doubles.DoubleHash.Strategy strategy ) { this( k.length, f, strategy ); if ( k.length != v.length ) throw new IllegalArgumentException( "The key array and the value array have different lengths (" + k.length + " and " + v.length + ")" ); for( int i = 0; i < k.length; i++ ) this.put( k[ i ], v[ i ] ); } /** Creates a new hash map with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor using the elements of two parallel arrays. * * @param k the array of keys of the new hash map. * @param v the array of corresponding values in the new hash map. * @param strategy the strategy. * @throws IllegalArgumentException if k and v have different lengths. */ public Double2IntOpenCustomHashMap( final double[] k, final int v[], final it.unimi.dsi.fastutil.doubles.DoubleHash.Strategy strategy ) { this( k, v, DEFAULT_LOAD_FACTOR, strategy ); } /** Returns the hashing strategy. * * @return the hashing strategy of this custom hash map. */ public it.unimi.dsi.fastutil.doubles.DoubleHash.Strategy strategy() { return strategy; } /* * The following methods implements some basic building blocks used by * all accessors. They are (and should be maintained) identical to those used in OpenHashSet.drv. */ public int put(final double k, final int v) { // The starting point. int pos = ( it.unimi.dsi.fastutil.HashCommon.murmurHash3( strategy.hashCode(k) ) ) & mask; // There's always an unused entry. while( used[ pos ] ) { if ( ( strategy.equals( (key[ pos ]), (k) ) ) ) { final int oldValue = value[ pos ]; value[ pos ] = v; return oldValue; } pos = ( pos + 1 ) & mask; } used[ pos ] = true; key[ pos ] = k; value[ pos ] = v; if ( ++size >= maxFill ) rehash( arraySize( size + 1, f ) ); if ( ASSERTS ) checkTable(); return defRetValue; } public Integer put( final Double ok, final Integer ov ) { final int v = ((ov).intValue()); final double k = ((ok).doubleValue()); // The starting point. int pos = ( it.unimi.dsi.fastutil.HashCommon.murmurHash3( strategy.hashCode(k) ) ) & mask; // There's always an unused entry. while( used[ pos ] ) { if ( ( strategy.equals( (key[ pos ]), (k) ) ) ) { final Integer oldValue = (Integer.valueOf(value[ pos ])); value[ pos ] = v; return oldValue; } pos = ( pos + 1 ) & mask; } used[ pos ] = true; key[ pos ] = k; value[ pos ] = v; if ( ++size >= maxFill ) rehash( arraySize( size + 1, f ) ); if ( ASSERTS ) checkTable(); return (null); } /** Adds an increment to value currently associated with a key. * * @param k the key. * @param incr the increment. * @return the old value, or the {@linkplain #defaultReturnValue() default return value} if no value was present for the given key. * @deprecated use addTo() instead; having the same name of a {@link java.util.Set} method turned out to be a recipe for disaster. */ @Deprecated public int add(final double k, final int incr) { return addTo( k, incr ); } /** Adds an increment to value currently associated with a key. * *

Note that this method respects the {@linkplain #defaultReturnValue() default return value} semantics: when * called with a key that does not currently appears in the map, the key * will be associated with the default return value plus * the given increment. * * @param k the key. * @param incr the increment. * @return the old value, or the {@linkplain #defaultReturnValue() default return value} if no value was present for the given key. */ public int addTo(final double k, final int incr) { // The starting point. int pos = ( it.unimi.dsi.fastutil.HashCommon.murmurHash3( strategy.hashCode(k) ) ) & mask; // There's always an unused entry. while( used[ pos ] ) { if ( ( strategy.equals( (key[ pos ]), (k) ) ) ) { final int oldValue = value[ pos ]; value[ pos ] += incr; return oldValue; } pos = ( pos + 1 ) & mask; } used[ pos ] = true; key[ pos ] = k; value[ pos ] = defRetValue + incr; if ( ++size >= maxFill ) rehash( arraySize( size + 1, f ) ); if ( ASSERTS ) checkTable(); return defRetValue; } /** 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 int shiftKeys( int pos ) { // Shift entries with the same hash. int last, slot; for(;;) { pos = ( ( last = pos ) + 1 ) & mask; while( used[ pos ] ) { slot = ( it.unimi.dsi.fastutil.HashCommon.murmurHash3( strategy.hashCode(key[ pos ]) ) ) & mask; if ( last <= pos ? last >= slot || slot > pos : last >= slot && slot > pos ) break; pos = ( pos + 1 ) & mask; } if ( ! used[ pos ] ) break; key[ last ] = key[ pos ]; value[ last ] = value[ pos ]; } used[ last ] = false; return last; } @SuppressWarnings("unchecked") public int remove( final double k ) { // The starting point. int pos = ( it.unimi.dsi.fastutil.HashCommon.murmurHash3( strategy.hashCode(k) ) ) & mask; // There's always an unused entry. while( used[ pos ] ) { if ( ( strategy.equals( (key[ pos ]), (k) ) ) ) { size--; final int v = value[ pos ]; shiftKeys( pos ); return v; } pos = ( pos + 1 ) & mask; } return defRetValue; } @SuppressWarnings("unchecked") public Integer remove( final Object ok ) { final double k = ((((Double)(ok)).doubleValue())); // The starting point. int pos = ( it.unimi.dsi.fastutil.HashCommon.murmurHash3( strategy.hashCode(k) ) ) & mask; // There's always an unused entry. while( used[ pos ] ) { if ( ( strategy.equals( (key[ pos ]), (k) ) ) ) { size--; final int v = value[ pos ]; shiftKeys( pos ); return (Integer.valueOf(v)); } pos = ( pos + 1 ) & mask; } return (null); } public Integer get( final Double ok ) { final double k = ((ok).doubleValue()); // The starting point. int pos = ( it.unimi.dsi.fastutil.HashCommon.murmurHash3( strategy.hashCode( k) ) ) & mask; // There's always an unused entry. while( used[ pos ] ) { if ( ( strategy.equals( (key[ pos ]), ( k) ) ) ) return (Integer.valueOf(value[ pos ])); pos = ( pos + 1 ) & mask; } return (null); } @SuppressWarnings("unchecked") public int get( final double k ) { // The starting point. int pos = ( it.unimi.dsi.fastutil.HashCommon.murmurHash3( strategy.hashCode(k) ) ) & mask; // There's always an unused entry. while( used[ pos ] ) { if ( ( strategy.equals( (key[ pos ]), (k) ) ) ) return value[ pos ]; pos = ( pos + 1 ) & mask; } return defRetValue; } @SuppressWarnings("unchecked") public boolean containsKey( final double k ) { // The starting point. int pos = ( it.unimi.dsi.fastutil.HashCommon.murmurHash3( strategy.hashCode(k) ) ) & mask; // There's always an unused entry. while( used[ pos ] ) { if ( ( strategy.equals( (key[ pos ]), (k) ) ) ) return true; pos = ( pos + 1 ) & mask; } return false; } public boolean containsValue( final int v ) { final int value[] = this.value; final boolean used[] = this.used; for( int i = n; i-- != 0; ) if ( used[ i ] && ( (value[ i ]) == (v) ) ) return true; return false; } /* Removes all elements from this map. * *

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()}. * */ public void clear() { if ( size == 0 ) return; size = 0; BooleanArrays.fill( used, false ); // We null all object entries so that the garbage collector can do its work. } public int size() { return size; } public boolean isEmpty() { return size == 0; } /** A no-op for backward compatibility. * * @param growthFactor unused. * @deprecated Since fastutil 6.1.0, hash tables are doubled when they are too full. */ @Deprecated public void growthFactor( int growthFactor ) {} /** Gets the growth factor (2). * * @return the growth factor of this set, which is fixed (2). * @see #growthFactor(int) * @deprecated Since fastutil 6.1.0, hash tables are doubled when they are too full. */ @Deprecated public int growthFactor() { return 16; } /** The entry class for a hash map does not record key and value, but * rather the position in the hash table of the corresponding entry. This * is necessary so that calls to {@link java.util.Map.Entry#setValue(Object)} are reflected in * the map */ private final class MapEntry implements Double2IntMap.Entry , Map.Entry { // The table index this entry refers to, or -1 if this entry has been deleted. private int index; MapEntry( final int index ) { this.index = index; } public Double getKey() { return (Double.valueOf(key[ index ])); } public double getDoubleKey() { return key[ index ]; } public Integer getValue() { return (Integer.valueOf(value[ index ])); } public int getIntValue() { return value[ index ]; } public int setValue( final int v ) { final int oldValue = value[ index ]; value[ index ] = v; return oldValue; } public Integer setValue( final Integer v ) { return (Integer.valueOf(setValue( ((v).intValue()) ))); } @SuppressWarnings("unchecked") public boolean equals( final Object o ) { if (!(o instanceof Map.Entry)) return false; Map.Entry e = (Map.Entry)o; return ( strategy.equals( (key[ index ]), (((e.getKey()).doubleValue())) ) ) && ( (value[ index ]) == (((e.getValue()).intValue())) ); } public int hashCode() { return ( strategy.hashCode(key[ index ]) ) ^ (value[ index ]); } public String toString() { return key[ index ] + "=>" + value[ index ]; } } /** An iterator over a hash map. */ private class MapIterator { /** The index 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 -pos -2 from the {@link #wrapped} list. */ int pos = Double2IntOpenCustomHashMap.this.n; /** The index 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 last = -1; /** A downward counter measuring how many entries must still be returned. */ int c = size; /** A lazily allocated list containing the keys of 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). */ DoubleArrayList wrapped; { final boolean used[] = Double2IntOpenCustomHashMap.this.used; if ( c != 0 ) while( ! used[ --pos ] ); } public boolean hasNext() { return c != 0; } public int nextEntry() { if ( ! hasNext() ) throw new NoSuchElementException(); c--; // We are just enumerating elements from the wrapped list. if ( pos < 0 ) { final double k = wrapped.getDouble( - ( last = --pos ) - 2 ); // The starting point. int pos = ( it.unimi.dsi.fastutil.HashCommon.murmurHash3( strategy.hashCode(k) ) ) & mask; // There's always an unused entry. while( used[ pos ] ) { if ( ( strategy.equals( (key[ pos ]), (k) ) ) ) return pos; pos = ( pos + 1 ) & mask; } } last = pos; //System.err.println( "Count: " + c ); if ( c != 0 ) { final boolean used[] = Double2IntOpenCustomHashMap.this.used; while ( pos-- != 0 && !used[ pos ] ); // When here pos < 0 there are no more elements to be enumerated by scanning, but wrapped might be nonempty. } return last; } /** 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 key. * * @param pos a starting position. * @return the position cleared by the shifting process. */ protected final int shiftKeys( int pos ) { // Shift entries with the same hash. int last, slot; for(;;) { pos = ( ( last = pos ) + 1 ) & mask; while( used[ pos ] ) { slot = ( it.unimi.dsi.fastutil.HashCommon.murmurHash3( strategy.hashCode(key[ pos ]) ) ) & mask; if ( last <= pos ? last >= slot || slot > pos : last >= slot && slot > pos ) break; pos = ( pos + 1 ) & mask; } if ( ! used[ pos ] ) break; if ( pos < last ) { // Wrapped entry. if ( wrapped == null ) wrapped = new DoubleArrayList (); wrapped.add( key[ pos ] ); } key[ last ] = key[ pos ]; value[ last ] = value[ pos ]; } used[ last ] = false; return last; } @SuppressWarnings("unchecked") public void remove() { if ( last == -1 ) throw new IllegalStateException(); if ( pos < -1 ) { // We're removing wrapped entries. Double2IntOpenCustomHashMap.this.remove( wrapped.getDouble( - pos - 2 ) ); last = -1; return; } size--; if ( shiftKeys( last ) == pos && c > 0 ) { c++; nextEntry(); } last = -1; // You can no longer remove this entry. if ( ASSERTS ) checkTable(); } public int skip( final int n ) { int i = n; while( i-- != 0 && hasNext() ) nextEntry(); return n - i - 1; } } private class EntryIterator extends MapIterator implements ObjectIterator { private MapEntry entry; public Double2IntMap.Entry next() { return entry = new MapEntry( nextEntry() ); } @Override public void remove() { super.remove(); entry.index = -1; // You cannot use a deleted entry. } } private class FastEntryIterator extends MapIterator implements ObjectIterator { final BasicEntry entry = new BasicEntry ( ((double)0), (0) ); public BasicEntry next() { final int e = nextEntry(); entry.key = key[ e ]; entry.value = value[ e ]; return entry; } } private final class MapEntrySet extends AbstractObjectSet implements FastEntrySet { public ObjectIterator iterator() { return new EntryIterator(); } public ObjectIterator fastIterator() { return new FastEntryIterator(); } @SuppressWarnings("unchecked") public boolean contains( final Object o ) { if ( !( o instanceof Map.Entry ) ) return false; final Map.Entry e = (Map.Entry)o; final double k = ((e.getKey()).doubleValue()); // The starting point. int pos = ( it.unimi.dsi.fastutil.HashCommon.murmurHash3( strategy.hashCode(k) ) ) & mask; // There's always an unused entry. while( used[ pos ] ) { if ( ( strategy.equals( (key[ pos ]), (k) ) ) ) return ( (value[ pos ]) == (((e.getValue()).intValue())) ); pos = ( pos + 1 ) & mask; } return false; } @SuppressWarnings("unchecked") public boolean remove( final Object o ) { if ( !( o instanceof Map.Entry ) ) return false; final Map.Entry e = (Map.Entry)o; final double k = ((e.getKey()).doubleValue()); // The starting point. int pos = ( it.unimi.dsi.fastutil.HashCommon.murmurHash3( strategy.hashCode(k) ) ) & mask; // There's always an unused entry. while( used[ pos ] ) { if ( ( strategy.equals( (key[ pos ]), (k) ) ) ) { Double2IntOpenCustomHashMap.this.remove( e.getKey() ); return true; } pos = ( pos + 1 ) & mask; } return false; } public int size() { return size; } public void clear() { Double2IntOpenCustomHashMap.this.clear(); } } public FastEntrySet double2IntEntrySet() { if ( entries == null ) entries = new MapEntrySet(); return entries; } /** An iterator on keys. * *

We simply override the {@link java.util.ListIterator#next()}/{@link java.util.ListIterator#previous()} methods * (and possibly their type-specific counterparts) so that they return keys * instead of entries. */ private final class KeyIterator extends MapIterator implements DoubleIterator { public KeyIterator() { super(); } public double nextDouble() { return key[ nextEntry() ]; } public Double next() { return (Double.valueOf(key[ nextEntry() ])); } } private final class KeySet extends AbstractDoubleSet { public DoubleIterator iterator() { return new KeyIterator(); } public int size() { return size; } public boolean contains( double k ) { return containsKey( k ); } public boolean remove( double k ) { final int oldSize = size; Double2IntOpenCustomHashMap.this.remove( k ); return size != oldSize; } public void clear() { Double2IntOpenCustomHashMap.this.clear(); } } public DoubleSet keySet() { if ( keys == null ) keys = new KeySet(); return keys; } /** An iterator on values. * *

We simply override the {@link java.util.ListIterator#next()}/{@link java.util.ListIterator#previous()} methods * (and possibly their type-specific counterparts) so that they return values * instead of entries. */ private final class ValueIterator extends MapIterator implements IntIterator { public ValueIterator() { super(); } public int nextInt() { return value[ nextEntry() ]; } public Integer next() { return (Integer.valueOf(value[ nextEntry() ])); } } public IntCollection values() { if ( values == null ) values = new AbstractIntCollection () { public IntIterator iterator() { return new ValueIterator(); } public int size() { return size; } public boolean contains( int v ) { return containsValue( v ); } public void clear() { Double2IntOpenCustomHashMap.this.clear(); } }; return values; } /** 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 the map, 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 map. * @see #trim(int) */ public boolean trim() { final int l = arraySize( size, f ); if ( l >= n ) return true; try { rehash( l ); } catch(OutOfMemoryError cantDoIt) { return false; } return true; } /** Rehashes this map if the table is too large. * *

Let N be the smallest table size that can hold * max(n,{@link #size()}) 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 map in a table of size * N. * *

This method is useful when reusing maps. {@linkplain #clear() Clearing a * map} leaves the table size untouched. If you are reusing a map * 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 maps. * * @param n the threshold for the trimming. * @return true if there was enough memory to trim the map. * @see #trim() */ public boolean trim( final int n ) { final int l = HashCommon.nextPowerOfTwo( (int)Math.ceil( n / f ) ); if ( this.n <= l ) return true; try { rehash( l ); } catch( OutOfMemoryError cantDoIt ) { return false; } return true; } /** Rehashes the map. * *

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 int newN ) { int i = 0, pos; final boolean used[] = this.used; double k; final double key[] = this.key; final int value[] = this.value; final int newMask = newN - 1; final double newKey[] = new double[ newN ]; final int newValue[] = new int[newN]; final boolean newUsed[] = new boolean[ newN ]; for( int j = size; j-- != 0; ) { while( ! used[ i ] ) i++; k = key[ i ]; pos = ( it.unimi.dsi.fastutil.HashCommon.murmurHash3( strategy.hashCode(k) ) ) & newMask; while ( newUsed[ pos ] ) pos = ( pos + 1 ) & newMask; newUsed[ pos ] = true; newKey[ pos ] = k; newValue[ pos ] = value[ i ]; i++; } n = newN; mask = newMask; maxFill = maxFill( n, f ); this.key = newKey; this.value = newValue; this.used = newUsed; } /** Returns a deep copy of this map. * *

This method performs a deep copy of this hash map; the data stored in the * map, however, is not cloned. Note that this makes a difference only for object keys. * * @return a deep copy of this map. */ @SuppressWarnings("unchecked") public Double2IntOpenCustomHashMap clone() { Double2IntOpenCustomHashMap c; try { c = (Double2IntOpenCustomHashMap )super.clone(); } catch(CloneNotSupportedException cantHappen) { throw new InternalError(); } c.keys = null; c.values = null; c.entries = null; c.key = key.clone(); c.value = value.clone(); c.used = used.clone(); c.strategy = strategy; return c; } /** Returns a hash code for this map. * * 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 map. */ public int hashCode() { int h = 0; for( int j = size, i = 0, t = 0; j-- != 0; ) { while( ! used[ i ] ) i++; t = ( strategy.hashCode(key[ i ]) ); t ^= (value[ i ]); h += t; i++; } return h; } private void writeObject(java.io.ObjectOutputStream s) throws java.io.IOException { final double key[] = this.key; final int value[] = this.value; final MapIterator i = new MapIterator(); s.defaultWriteObject(); for( int j = size, e; j-- != 0; ) { e = i.nextEntry(); s.writeDouble( key[ e ] ); s.writeInt( value[ e ] ); } } @SuppressWarnings("unchecked") private void readObject(java.io.ObjectInputStream s) throws java.io.IOException, ClassNotFoundException { s.defaultReadObject(); n = arraySize( size, f ); maxFill = maxFill( n, f ); mask = n - 1; final double key[] = this.key = new double[ n ]; final int value[] = this.value = new int[ n ]; final boolean used[] = this.used = new boolean[ n ]; double k; int v; for( int i = size, pos = 0; i-- != 0; ) { k = s.readDouble(); v = s.readInt(); pos = ( it.unimi.dsi.fastutil.HashCommon.murmurHash3( strategy.hashCode(k) ) ) & mask; while ( used[ pos ] ) pos = ( pos + 1 ) & mask; used[ pos ] = true; key[ pos ] = k; value[ pos ] = v; } if ( ASSERTS ) checkTable(); } private void checkTable() {} }





© 2015 - 2024 Weber Informatics LLC | Privacy Policy