src.it.unimi.dsi.fastutil.chars.CharLinkedOpenCustomHashSet 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) */
/* Primitive-type-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.chars;
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.Collection;
import java.util.Iterator;
import java.util.NoSuchElementException;
/** A type-specific linked hash set with with a fast, small-footprint implementation.
*
* Instances of this class use a hash table to represent a set. 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.
*
*
Iterators generated by this set will enumerate elements in the same order in which they
* have been added to the set (addition of elements already present
* in the set does not change the iteration order). Note that this order has nothing in common with the natural
* order of the keys. The order is kept by means of a doubly linked list, represented
* via an array of longs parallel to the table.
*
*
This class implements the interface of a sorted set, so to allow easy
* access of the iteration order: for instance, you can get the first element
* in iteration order with {@link #first()} without having to create an
* iterator; however, this class partially violates the {@link java.util.SortedSet}
* contract because all subset methods throw an exception and {@link
* #comparator()} returns always null.
*
*
Additional methods, such as addAndMoveToFirst(), make it easy
* to use instances of this class as a cache (e.g., with LRU policy).
*
*
The iterators provided by this class are type-specific {@linkplain
* java.util.ListIterator list iterators}, and can be started at any
* element which is in the set (if the provided element
* is not in the set, a {@link NoSuchElementException} exception will be thrown).
* If, however, the provided element is not the first or last element in the
* set, the first access to the list index will require linear time, as in the worst case
* the entire set must be scanned in iteration order to retrieve the positional
* index of the starting element. If you use just the methods of a type-specific {@link it.unimi.dsi.fastutil.BidirectionalIterator},
* however, all operations will be performed in constant time.
*
* @see Hash
* @see HashCommon
*/
public class CharLinkedOpenCustomHashSet extends AbstractCharSortedSet implements java.io.Serializable, Cloneable, Hash {
private static final long serialVersionUID = 0L;
private static final boolean ASSERTS = false;
/** The array of keys. */
protected transient char key[];
/** 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;
/** The index of the first entry in iteration order. It is valid iff {@link #size} is nonzero; otherwise, it contains -1. */
protected transient int first = -1;
/** The index of the last entry in iteration order. It is valid iff {@link #size} is nonzero; otherwise, it contains -1. */
protected transient int last = -1;
/** For each entry, the next and the previous entry in iteration order,
* stored as ((prev & 0xFFFFFFFFL) << 32) | (next & 0xFFFFFFFFL).
* The first entry contains predecessor -1, and the last entry
* contains successor -1. */
protected transient long link[];
/** The hash strategy of this custom set. */
protected it.unimi.dsi.fastutil.chars.CharHash.Strategy strategy;
/** Creates a new hash 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 hash set.
* @param f the load factor.
* @param strategy the strategy.
*/
@SuppressWarnings("unchecked")
public CharLinkedOpenCustomHashSet( final int expected, final float f, final it.unimi.dsi.fastutil.chars.CharHash.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 char[ n ];
used = new boolean[ n ];
link = new long[ n ];
}
/** Creates a new hash set with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor.
*
* @param expected the expected number of elements in the hash set.
* @param strategy the strategy.
*/
public CharLinkedOpenCustomHashSet( final int expected, final it.unimi.dsi.fastutil.chars.CharHash.Strategy strategy ) {
this( expected, DEFAULT_LOAD_FACTOR, strategy );
}
/** Creates a new hash set with initial expected {@link Hash#DEFAULT_INITIAL_SIZE} elements
* and {@link Hash#DEFAULT_LOAD_FACTOR} as load factor.
* @param strategy the strategy.
*/
public CharLinkedOpenCustomHashSet( final it.unimi.dsi.fastutil.chars.CharHash.Strategy strategy ) {
this( DEFAULT_INITIAL_SIZE, DEFAULT_LOAD_FACTOR, strategy );
}
/** Creates a new hash set copying a given collection.
*
* @param c a {@link Collection} to be copied into the new hash set.
* @param f the load factor.
* @param strategy the strategy.
*/
public CharLinkedOpenCustomHashSet( final Collection c, final float f, final it.unimi.dsi.fastutil.chars.CharHash.Strategy strategy ) {
this( c.size(), f, strategy );
addAll( c );
}
/** Creates a new hash 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 set.
* @param strategy the strategy.
*/
public CharLinkedOpenCustomHashSet( final Collection c, final it.unimi.dsi.fastutil.chars.CharHash.Strategy strategy ) {
this( c, DEFAULT_LOAD_FACTOR, strategy );
}
/** Creates a new hash set copying a given type-specific collection.
*
* @param c a type-specific collection to be copied into the new hash set.
* @param f the load factor.
* @param strategy the strategy.
*/
public CharLinkedOpenCustomHashSet( final CharCollection c, final float f, it.unimi.dsi.fastutil.chars.CharHash.Strategy strategy ) {
this( c.size(), f, strategy );
addAll( c );
}
/** Creates a new hash 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 set.
* @param strategy the strategy.
*/
public CharLinkedOpenCustomHashSet( final CharCollection c, final it.unimi.dsi.fastutil.chars.CharHash.Strategy strategy ) {
this( c, DEFAULT_LOAD_FACTOR, strategy );
}
/** Creates a new hash set using elements provided by a type-specific iterator.
*
* @param i a type-specific iterator whose elements will fill the set.
* @param f the load factor.
* @param strategy the strategy.
*/
public CharLinkedOpenCustomHashSet( final CharIterator i, final float f, final it.unimi.dsi.fastutil.chars.CharHash.Strategy strategy ) {
this( DEFAULT_INITIAL_SIZE, f, strategy );
while( i.hasNext() ) add( i.nextChar() );
}
/** Creates a new hash 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 set.
* @param strategy the strategy.
*/
public CharLinkedOpenCustomHashSet( final CharIterator i, final it.unimi.dsi.fastutil.chars.CharHash.Strategy strategy ) {
this( i, DEFAULT_LOAD_FACTOR, strategy );
}
/** Creates a new hash set using elements provided by an iterator.
*
* @param i an iterator whose elements will fill the set.
* @param f the load factor.
* @param strategy the strategy.
*/
public CharLinkedOpenCustomHashSet( final Iterator i, final float f, final it.unimi.dsi.fastutil.chars.CharHash.Strategy strategy ) {
this( CharIterators.asCharIterator( i ), f, strategy );
}
/** Creates a new hash set with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor using elements provided by an iterator.
*
* @param i an iterator whose elements will fill the set.
* @param strategy the strategy.
*/
public CharLinkedOpenCustomHashSet( final Iterator i, final it.unimi.dsi.fastutil.chars.CharHash.Strategy strategy ) {
this( CharIterators.asCharIterator( i ), strategy );
}
/** Creates a new hash set and fills it with the elements of a given array.
*
* @param a an array whose elements will be used to fill the set.
* @param offset the first element to use.
* @param length the number of elements to use.
* @param f the load factor.
* @param strategy the strategy.
*/
public CharLinkedOpenCustomHashSet( final char[] a, final int offset, final int length, final float f, final it.unimi.dsi.fastutil.chars.CharHash.Strategy strategy ) {
this( length < 0 ? 0 : length, f, strategy );
CharArrays.ensureOffsetLength( a, offset, length );
for( int i = 0; i < length; i++ ) add( a[ offset + i ] );
}
/** Creates a new hash 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 set.
* @param offset the first element to use.
* @param length the number of elements to use.
* @param strategy the strategy.
*/
public CharLinkedOpenCustomHashSet( final char[] a, final int offset, final int length, final it.unimi.dsi.fastutil.chars.CharHash.Strategy strategy ) {
this( a, offset, length, DEFAULT_LOAD_FACTOR, strategy );
}
/** Creates a new hash set copying the elements of an array.
*
* @param a an array to be copied into the new hash set.
* @param f the load factor.
* @param strategy the strategy.
*/
public CharLinkedOpenCustomHashSet( final char[] a, final float f, final it.unimi.dsi.fastutil.chars.CharHash.Strategy strategy ) {
this( a, 0, a.length, f, strategy );
}
/** Creates a new hash 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 set.
* @param strategy the strategy.
*/
public CharLinkedOpenCustomHashSet( final char[] a, final it.unimi.dsi.fastutil.chars.CharHash.Strategy strategy ) {
this( a, DEFAULT_LOAD_FACTOR, strategy );
}
/** Returns the hashing strategy.
*
* @return the hashing strategy of this custom hash set.
*/
public it.unimi.dsi.fastutil.chars.CharHash.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 HashMap.drv.
*/
public boolean add( final char 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 false;
pos = ( pos + 1 ) & mask;
}
used[ pos ] = true;
key[ pos ] = k;
if ( size == 0 ) {
first = last = pos;
// Special case of SET(link[ pos ], -1, -1);
link[ pos ] = -1L;
}
else {
link[ last ] ^= ( ( link[ last ] ^ ( pos & 0xFFFFFFFFL ) ) & 0xFFFFFFFFL );
link[ pos ] = ( ( last & 0xFFFFFFFFL ) << 32 ) | ( -1 & 0xFFFFFFFFL );
last = pos;
}
if ( ++size >= maxFill ) rehash( arraySize( size + 1, f ) );
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 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 ];
fixPointers( pos, last );
}
used[ last ] = false;
return last;
}
@SuppressWarnings("unchecked")
public boolean remove( final char 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--;
fixPointers( pos );
shiftKeys( pos );
if ( ASSERTS ) checkTable();
return true;
}
pos = ( pos + 1 ) & mask;
}
return false;
}
@SuppressWarnings("unchecked")
public boolean contains( final char 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;
}
/** Removes the first key in iteration order.
* @return the first key.
* @throws NoSuchElementException is this set is empty.
*/
public char removeFirstChar() {
if ( size == 0 ) throw new NoSuchElementException();
--size;
final int pos = first;
// Abbreviated version of fixPointers(pos)
first = (int) link[ pos ];
if ( 0 <= first ) {
// Special case of SET_PREV( link[ first ], -1 )
link[ first ] |= (-1 & 0xFFFFFFFFL) << 32;
}
final char k = key[ pos ];
shiftKeys( pos );
return k;
}
/** Removes the the last key in iteration order.
* @return the last key.
* @throws NoSuchElementException is this set is empty.
*/
public char removeLastChar() {
if ( size == 0 ) throw new NoSuchElementException();
--size;
final int pos = last;
// Abbreviated version of fixPointers(pos)
last = (int) ( link[ pos ] >>> 32 );
if ( 0 <= last ) {
// Special case of SET_NEXT( link[ last ], -1 )
link[ last ] |= -1 & 0xFFFFFFFFL;
}
final char k = key[ pos ];
shiftKeys( pos );
return k;
}
private void moveIndexToFirst( final int i ) {
if ( size == 1 || first == i ) return;
if ( last == i ) {
last = (int) ( link[ i ] >>> 32 );
// Special case of SET_NEXT( link[ last ], -1 );
link[ last ] |= -1 & 0xFFFFFFFFL;
}
else {
final long linki = link[ i ];
final int prev = (int) ( linki >>> 32 );
final int next = (int) linki;
link[ prev ] ^= ( ( link[ prev ] ^ ( linki & 0xFFFFFFFFL ) ) & 0xFFFFFFFFL );
link[ next ] ^= ( ( link[ next ] ^ ( linki & 0xFFFFFFFF00000000L ) ) & 0xFFFFFFFF00000000L );
}
link[ first ] ^= ( ( link[ first ] ^ ( ( i & 0xFFFFFFFFL ) << 32 ) ) & 0xFFFFFFFF00000000L );
link[ i ] = ( ( -1 & 0xFFFFFFFFL ) << 32 ) | ( first & 0xFFFFFFFFL );
first = i;
}
private void moveIndexToLast( final int i ) {
if ( size == 1 || last == i ) return;
if ( first == i ) {
first = (int) link[ i ];
// Special case of SET_PREV( link[ first ], -1 );
link[ first ] |= (-1 & 0xFFFFFFFFL) << 32;
}
else {
final long linki = link[ i ];
final int prev = (int) ( linki >>> 32 );
final int next = (int) linki;
link[ prev ] ^= ( ( link[ prev ] ^ ( linki & 0xFFFFFFFFL ) ) & 0xFFFFFFFFL );
link[ next ] ^= ( ( link[ next ] ^ ( linki & 0xFFFFFFFF00000000L ) ) & 0xFFFFFFFF00000000L );
}
link[ last ] ^= ( ( link[ last ] ^ ( i & 0xFFFFFFFFL ) ) & 0xFFFFFFFFL );
link[ i ] = ( ( last & 0xFFFFFFFFL ) << 32 ) | ( -1 & 0xFFFFFFFFL );
last = i;
}
/** Adds a key to the set; if the key is already present, it is moved to the first position of the iteration order.
*
* @param k the key.
* @return true if the key was not present.
*/
public boolean addAndMoveToFirst( final char k ) {
final char key[] = this.key;
final boolean used[] = this.used;
final int mask = this.mask;
// 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( (k), (key[ pos ]) ) ) ) {
moveIndexToFirst( pos );
return false;
}
pos = ( pos + 1 ) & mask;
}
used[ pos ] = true;
key[ pos ] = k;
if ( size == 0 ) {
first = last = pos;
// Special case of SET_UPPER_LOWER( link[ pos ], -1, -1 );
link[ pos ] = -1L;
}
else {
link[ first ] ^= ( ( link[ first ] ^ ( ( pos & 0xFFFFFFFFL ) << 32 ) ) & 0xFFFFFFFF00000000L );
link[ pos ] = ( ( -1 & 0xFFFFFFFFL ) << 32 ) | ( first & 0xFFFFFFFFL );
first = pos;
}
if ( ++size >= maxFill ) rehash( arraySize( size, f ) );
if ( ASSERTS ) checkTable();
return true;
}
/** Adds a key to the set; if the key is already present, it is moved to the last position of the iteration order.
*
* @param k the key.
* @return true if the key was not present.
*/
public boolean addAndMoveToLast( final char k ) {
final char key[] = this.key;
final boolean used[] = this.used;
final int mask = this.mask;
// 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( (k), (key[ pos ]) ) ) ) {
moveIndexToLast( pos );
return false;
}
pos = ( pos + 1 ) & mask;
}
used[ pos ] = true;
key[ pos ] = k;
if ( size == 0 ) {
first = last = pos;
// Special case of SET_UPPER_LOWER( link[ pos ], -1, -1 );
link[ pos ] = -1L;
}
else {
link[ last ] ^= ( ( link[ last ] ^ ( pos & 0xFFFFFFFFL ) ) & 0xFFFFFFFFL );
link[ pos ] = ( ( last & 0xFFFFFFFFL ) << 32 ) | ( -1 & 0xFFFFFFFFL );
last = pos;
}
if ( ++size >= maxFill ) rehash( arraySize( size, f ) );
if ( ASSERTS ) checkTable();
return true;
}
/* 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()}.
*
*/
public void clear() {
if ( size == 0 ) return;
size = 0;
BooleanArrays.fill( used, false );
first = last = -1;
}
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;
}
/** Modifies the {@link #link} vector so that the given entry is removed.
*
*
If the given entry is the first or the last one, this method will complete
* in constant time; otherwise, it will have to search for the given entry.
*
* @param i the index of an entry.
*/
protected void fixPointers( final int i ) {
if ( size == 0 ) {
first = last = -1;
return;
}
if ( first == i ) {
first = (int) link[ i ];
if (0 <= first) {
// Special case of SET_PREV( link[ first ], -1 )
link[ first ] |= (-1 & 0xFFFFFFFFL) << 32;
}
return;
}
if ( last == i ) {
last = (int) ( link[ i ] >>> 32 );
if (0 <= last) {
// Special case of SET_NEXT( link[ last ], -1 )
link[ last ] |= -1 & 0xFFFFFFFFL;
}
return;
}
final long linki = link[ i ];
final int prev = (int) ( linki >>> 32 );
final int next = (int) linki;
link[ prev ] ^= ( ( link[ prev ] ^ ( linki & 0xFFFFFFFFL ) ) & 0xFFFFFFFFL );
link[ next ] ^= ( ( link[ next ] ^ ( linki & 0xFFFFFFFF00000000L ) ) & 0xFFFFFFFF00000000L );
}
/** Modifies the {@link #link} vector for a shift from s to d.
*
*
If the given entry is the first or the last one, this method will complete
* in constant time; otherwise, it will have to search for the given entry.
*
* @param s the source position.
* @param d the destination position.
*/
protected void fixPointers( int s, int d ) {
if ( size == 1 ) {
first = last = d;
// Special case of SET(link[ d ], -1, -1)
link[ d ] = -1L;
return;
}
if ( first == s ) {
first = d;
link[ (int) link[ s ] ] ^= ( ( link[ (int) link[ s ] ] ^ ( ( d & 0xFFFFFFFFL ) << 32 ) ) & 0xFFFFFFFF00000000L );
link[ d ] = link[ s ];
return;
}
if ( last == s ) {
last = d;
link[ (int) ( link[ s ] >>> 32 )] ^= ( ( link[ (int) ( link[ s ] >>> 32 )] ^ ( d & 0xFFFFFFFFL ) ) & 0xFFFFFFFFL );
link[ d ] = link[ s ];
return;
}
final long links = link[ s ];
final int prev = (int) ( links >>> 32 );
final int next = (int) links;
link[ prev ] ^= ( ( link[ prev ] ^ ( d & 0xFFFFFFFFL ) ) & 0xFFFFFFFFL );
link[ next ] ^= ( ( link[ next ] ^ ( ( d & 0xFFFFFFFFL ) << 32 ) ) & 0xFFFFFFFF00000000L );
link[ d ] = links;
}
/** Returns the first element of this set in iteration order.
*
* @return the first element in iteration order.
*/
public char firstChar() {
if ( size == 0 ) throw new NoSuchElementException();
return key[ first ];
}
/** Returns the last element of this set in iteration order.
*
* @return the last element in iteration order.
*/
public char lastChar() {
if ( size == 0 ) throw new NoSuchElementException();
return key[ last ];
}
public CharSortedSet tailSet( char from ) { throw new UnsupportedOperationException(); }
public CharSortedSet headSet( char to ) { throw new UnsupportedOperationException(); }
public CharSortedSet subSet( char from, char to ) { throw new UnsupportedOperationException(); }
public CharComparator comparator() { return null; }
/** A list iterator over a linked set.
*
*
This class provides a list iterator over a linked hash set. The empty constructor runs in
* constant time. The one-argument constructor needs to search for the given element, but it is
* optimized for the case of {@link java.util.SortedSet#last()}, in which case runs in constant time, too.
*/
private class SetIterator extends AbstractCharListIterator {
/** The entry that will be returned by the next call to {@link java.util.ListIterator#previous()} (or null if no previous entry exists). */
int prev = -1;
/** The entry that will be returned by the next call to {@link java.util.ListIterator#next()} (or null if no next entry exists). */
int next = -1;
/** The last entry that was returned (or -1 if we did not iterate or used {@link #remove()}). */
int curr = -1;
/** The current index (in the sense of a {@link java.util.ListIterator}). When -1, we do not know the current index.*/
int index = -1;
SetIterator() {
next = first;
index = 0;
}
SetIterator( char from ) {
if ( ( strategy.equals( (key[ last ]), (from) ) ) ) {
prev = last;
index = size;
}
else {
// The starting point.
int pos = ( it.unimi.dsi.fastutil.HashCommon.murmurHash3( strategy.hashCode(from) ) ) & mask;
// There's always an unused entry.
while( used[ pos ] ) {
if ( ( strategy.equals( (key[ pos ]), (from) ) ) ) {
// Note: no valid index known.
next = (int) link[ pos ];
prev = pos;
return;
}
pos = ( pos + 1 ) & mask;
}
throw new NoSuchElementException( "The key " + from + " does not belong to this set." );
}
}
public boolean hasNext() { return next != -1; }
public boolean hasPrevious() { return prev != -1; }
public char nextChar() {
if ( ! hasNext() ) throw new NoSuchElementException();
curr = next;
next = (int) link[ curr ];
prev = curr;
if ( index >= 0 ) index++;
if ( ASSERTS ) assert used[ curr ] : "Position " + curr + " is not used";
return key[ curr ];
}
public char previousChar() {
if ( ! hasPrevious() ) throw new NoSuchElementException();
curr = prev;
prev = (int) ( link[ curr ] >>> 32 );
next = curr;
if ( index >= 0 ) index--;
return key[ curr ];
}
private final void ensureIndexKnown() {
if ( index >= 0 ) return;
if ( prev == -1 ) {
index = 0;
return;
}
if ( next == -1 ) {
index = size;
return;
}
int pos = first;
index = 1;
while( pos != prev ) {
pos = (int) link[ pos ];
index++;
}
}
public int nextIndex() {
ensureIndexKnown();
return index;
}
public int previousIndex() {
ensureIndexKnown();
return index - 1;
}
@SuppressWarnings("unchecked")
public void remove() {
ensureIndexKnown();
if ( curr == -1 ) throw new IllegalStateException();
if ( curr == prev ) {
/* If the last operation was a next(), we are removing an entry that preceeds
the current index, and thus we must decrement it. */
index--;
prev = (int) ( link[ curr ] >>> 32 );
}
else
next = (int) link[ curr ];
size--;
/* Now we manually fix the pointers. Because of our knowledge of next
and prev, this is going to be faster than calling fixPointers(). */
if ( prev == -1 ) first = next;
else
link[ prev ] ^= ( ( link[ prev ] ^ ( next & 0xFFFFFFFFL ) ) & 0xFFFFFFFFL );
if ( next == -1 ) last = prev;
else
link[ next ] ^= ( ( link[ next ] ^ ( ( prev & 0xFFFFFFFFL ) << 32 ) ) & 0xFFFFFFFF00000000L );
int last, slot, pos = curr;
// We have to horribly duplicate the shiftKeys() code because we need to update next/prev.
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 ];
if ( next == pos ) next = last;
if ( prev == pos ) prev = last;
fixPointers( pos, last );
}
used[ last ] = false;
curr = -1;
}
}
/** Returns a type-specific list iterator on the elements in this set, starting from a given element of the set.
* Please see the class documentation for implementation details.
*
* @param from an element to start from.
* @return a type-specific list iterator starting at the given element.
* @throws IllegalArgumentException if from does not belong to the set.
*/
public CharListIterator iterator( char from ) {
return new SetIterator( from );
}
public CharListIterator 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(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 set 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 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 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 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 int newN ) {
int i = first, prev = -1, newPrev = -1, t, pos;
char k;
final char key[] = this.key;
final int newMask = newN - 1;
final char newKey[] = new char[ newN ];
final boolean newUsed[] = new boolean[ newN ];
final long link[] = this.link;
final long newLink[] = new long[ newN ];
first = -1;
for( int j = size; j-- != 0; ) {
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;
if ( prev != -1 ) {
newLink[ newPrev ] ^= ( ( newLink[ newPrev ] ^ ( pos & 0xFFFFFFFFL ) ) & 0xFFFFFFFFL );
newLink[ pos ] ^= ( ( newLink[ pos ] ^ ( ( newPrev & 0xFFFFFFFFL ) << 32 ) ) & 0xFFFFFFFF00000000L );
newPrev = pos;
}
else {
newPrev = first = pos;
// Special case of SET(newLink[ pos ], -1, -1);
newLink[ pos ] = -1L;
}
t = i;
i = (int) link[ i ];
prev = t;
}
n = newN;
mask = newMask;
maxFill = maxFill( n, f );
this.key = newKey;
this.used = newUsed;
this.link = newLink;
this.last = newPrev;
if ( newPrev != -1 )
// Special case of SET_NEXT( newLink[ newPrev ], -1 );
newLink[ newPrev ] |= -1 & 0xFFFFFFFFL;
}
/** Returns a deep copy of this set.
*
*
This method performs a deep copy of this 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 set.
*/
@SuppressWarnings("unchecked")
public CharLinkedOpenCustomHashSet clone() {
CharLinkedOpenCustomHashSet c;
try {
c = (CharLinkedOpenCustomHashSet )super.clone();
}
catch(CloneNotSupportedException cantHappen) {
throw new InternalError();
}
c.key = key.clone();
c.used = used.clone();
c.link = link.clone();
c.strategy = strategy;
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() {
int h = 0, i = 0, j = size;
while( j-- != 0 ) {
while( ! used[ i ] ) i++;
h += ( strategy.hashCode(key[ i ]) );
i++;
}
return h;
}
private void writeObject(java.io.ObjectOutputStream s) throws java.io.IOException {
final CharIterator i = iterator();
s.defaultWriteObject();
for( int j = size; j-- != 0; ) s.writeChar( i.nextChar() );
}
@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 char key[] = this.key = new char[ n ];
final boolean used[] = this.used = new boolean[ n ];
final long link[] = this.link = new long[ n ];
int prev = -1;
first = last = -1;
char k;
for( int i = size, pos = 0; i-- != 0; ) {
k = s.readChar();
pos = ( it.unimi.dsi.fastutil.HashCommon.murmurHash3( strategy.hashCode(k) ) ) & mask;
while ( used[ pos ] ) pos = ( pos + 1 ) & mask;
used[ pos ] = true;
key[ pos ] = k;
if ( first != -1 ) {
link[ prev ] ^= ( ( link[ prev ] ^ ( pos & 0xFFFFFFFFL ) ) & 0xFFFFFFFFL );
link[ pos ] ^= ( ( link[ pos ] ^ ( ( prev & 0xFFFFFFFFL ) << 32 ) ) & 0xFFFFFFFF00000000L );
prev = pos;
}
else {
prev = first = pos;
// Special case of SET_PREV( newLink[ pos ], -1 );
link[ pos ] |= (-1L & 0xFFFFFFFFL) << 32;
}
}
last = prev;
if ( prev != -1 )
// Special case of SET_NEXT( link[ prev ], -1 );
link[ prev ] |= -1 & 0xFFFFFFFFL;
if ( ASSERTS ) checkTable();
}
private void checkTable() {}
}