/* 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) 2002-2014 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.ints;
import java.util.Iterator;
import java.util.ListIterator;
import java.util.NoSuchElementException;
/** A class providing static methods and objects that do useful things with type-specific iterators.
*
* @see Iterator
*/
public class IntIterators {
private IntIterators() {}
/** A class returning no elements and a type-specific iterator interface.
*
* <P>This class may be useful to implement your own in case you subclass
* a type-specific iterator.
*/
public static class EmptyIterator extends AbstractIntListIterator implements java.io.Serializable, Cloneable {
private static final long serialVersionUID = -7046029254386353129L;
protected EmptyIterator() {}
public boolean hasNext() { return false; }
public boolean hasPrevious() { return false; }
public int nextInt() { throw new NoSuchElementException(); }
public int previousInt() { throw new NoSuchElementException(); }
public int nextIndex() { return 0; }
public int previousIndex() { return -1; }
public int skip( int n ) { return 0; };
public int back( int n ) { return 0; };
public Object clone() { return EMPTY_ITERATOR; }
private Object readResolve() { return EMPTY_ITERATOR; }
}
/** An empty iterator (immutable). It is serializable and cloneable.
*
* <P>The class of this objects represent an abstract empty iterator
* that can iterate as a type-specific (list) iterator.
*/
@SuppressWarnings("rawtypes")
public final static EmptyIterator EMPTY_ITERATOR = new EmptyIterator();
/** An iterator returning a single element. */
private static class SingletonIterator extends AbstractIntListIterator {
private final int element;
private int curr;
public SingletonIterator( final int element ) {
this.element = element;
}
public boolean hasNext() { return curr == 0; }
public boolean hasPrevious() { return curr == 1; }
public int nextInt() {
if ( ! hasNext() ) throw new NoSuchElementException();
curr = 1;
return element;
}
public int previousInt() {
if ( ! hasPrevious() ) throw new NoSuchElementException();
curr = 0;
return element;
}
public int nextIndex() {
return curr;
}
public int previousIndex() {
return curr - 1;
}
}
/** Returns an iterator that iterates just over the given element.
*
* @param element the only element to be returned by a type-specific list iterator.
* @return an iterator that iterates just over <code>element</code>.
*/
public static IntListIterator singleton( final int element ) {
return new SingletonIterator ( element );
}
/** A class to wrap arrays in iterators. */
private static class ArrayIterator extends AbstractIntListIterator {
private final int[] array;
private final int offset, length;
private int curr;
public ArrayIterator( final int[] array, final int offset, final int length ) {
this.array = array;
this.offset = offset;
this.length = length;
}
public boolean hasNext() { return curr < length; }
public boolean hasPrevious() { return curr > 0; }
public int nextInt() {
if ( ! hasNext() ) throw new NoSuchElementException();
return array[ offset + curr++ ];
}
public int previousInt() {
if ( ! hasPrevious() ) throw new NoSuchElementException();
return array[ offset + --curr ];
}
public int skip( int n ) {
if ( n <= length - curr ) {
curr += n;
return n;
}
n = length - curr;
curr = length;
return n;
}
public int back( int n ) {
if ( n <= curr ) {
curr -= n;
return n;
}
n = curr;
curr = 0;
return n;
}
public int nextIndex() {
return curr;
}
public int previousIndex() {
return curr - 1;
}
}
/** Wraps the given part of an array into a type-specific list iterator.
*
* <P>The type-specific list iterator returned by this method will iterate
* <code>length</code> times, returning consecutive elements of the given
* array starting from the one with index <code>offset</code>.
*
* @param array an array to wrap into a type-specific list iterator.
* @param offset the first element of the array to be returned.
* @param length the number of elements to return.
*/
public static IntListIterator wrap( final int[] array, final int offset, final int length ) {
IntArrays.ensureOffsetLength( array, offset, length );
return new ArrayIterator ( array, offset, length );
}
/** Wraps the given array into a type-specific list iterator.
*
* <P>The type-specific list iterator returned by this method will return
* all elements of the given array.
*
* @param array an array to wrap into a type-specific list iterator.
*/
public static IntListIterator wrap( final int[] array ) {
return new ArrayIterator ( array, 0, array.length );
}
/** Unwraps an iterator into an array starting at a given offset for a given number of elements.
*
* <P>This method iterates over the given type-specific iterator and stores the elements
* returned, up to a maximum of <code>length</code>, in the given array starting at <code>offset</code>.
* The number of actually unwrapped elements is returned (it may be less than <code>max</code> if
* the iterator emits less than <code>max</code> elements).
*
* @param i a type-specific iterator.
* @param array an array to contain the output of the iterator.
* @param offset the first element of the array to be returned.
* @param max the maximum number of elements to unwrap.
* @return the number of elements unwrapped.
*/
public static int unwrap( final IntIterator i, final int array[], int offset, final int max ) {
if ( max < 0 ) throw new IllegalArgumentException( "The maximum number of elements (" + max + ") is negative" );
if ( offset < 0 || offset + max > array.length ) throw new IllegalArgumentException();
int j = max;
while( j-- != 0 && i.hasNext() ) array[ offset++ ] = i.nextInt();
return max - j - 1;
}
/** Unwraps an iterator into an array.
*
* <P>This method iterates over the given type-specific iterator and stores the
* elements returned in the given array. The iteration will stop when the
* iterator has no more elements or when the end of the array has been reached.
*
* @param i a type-specific iterator.
* @param array an array to contain the output of the iterator.
* @return the number of elements unwrapped.
*/
public static int unwrap( final IntIterator i, final int array[] ) {
return unwrap( i, array, 0, array.length );
}
/** Unwraps an iterator, returning an array, with a limit on the number of elements.
*
* <P>This method iterates over the given type-specific iterator and returns an array
* containing the elements returned by the iterator. At most <code>max</code> elements
* will be returned.
*
* @param i a type-specific iterator.
* @param max the maximum number of elements to be unwrapped.
* @return an array containing the elements returned by the iterator (at most <ocde>max</code>).
*/
@SuppressWarnings("unchecked")
public static int[] unwrap( final IntIterator i, int max ) {
if ( max < 0 ) throw new IllegalArgumentException( "The maximum number of elements (" + max + ") is negative" );
int array[] = new int[ 16 ];
int j = 0;
while( max-- != 0 && i.hasNext() ) {
if ( j == array.length ) array = IntArrays.grow( array, j + 1 );
array[ j++ ] = i.nextInt();
}
return IntArrays.trim( array, j );
}
/** Unwraps an iterator, returning an array.
*
* <P>This method iterates over the given type-specific iterator and returns an array
* containing the elements returned by the iterator.
*
* @param i a type-specific iterator.
* @return an array containing the elements returned by the iterator.
*/
public static int[] unwrap( final IntIterator i ) {
return unwrap( i, Integer.MAX_VALUE );
}
/** Unwraps an iterator into a type-specific collection, with a limit on the number of elements.
*
* <P>This method iterates over the given type-specific iterator and stores the elements
* returned, up to a maximum of <code>max</code>, in the given type-specific collection.
* The number of actually unwrapped elements is returned (it may be less than <code>max</code> if
* the iterator emits less than <code>max</code> elements).
*
* @param i a type-specific iterator.
* @param c a type-specific collection array to contain the output of the iterator.
* @param max the maximum number of elements to unwrap.
* @return the number of elements unwrapped. Note that
* this is the number of elements returned by the iterator, which is not necessarily the number
* of elements that have been added to the collection (because of duplicates).
*/
public static int unwrap( final IntIterator i, final IntCollection c, final int max ) {
if ( max < 0 ) throw new IllegalArgumentException( "The maximum number of elements (" + max + ") is negative" );
int j = max;
while( j-- != 0 && i.hasNext() ) c.add( i.nextInt() );
return max - j - 1;
}
/** Unwraps an iterator into a type-specific collection.
*
* <P>This method iterates over the given type-specific iterator and stores the
* elements returned in the given type-specific collection. The returned count on the number
* unwrapped elements is a long, so that it will work also with very large collections.
*
* @param i a type-specific iterator.
* @param c a type-specific collection to contain the output of the iterator.
* @return the number of elements unwrapped. Note that
* this is the number of elements returned by the iterator, which is not necessarily the number
* of elements that have been added to the collection (because of duplicates).
*/
public static long unwrap( final IntIterator i, final IntCollection c ) {
long n = 0;
while( i.hasNext() ) {
c.add( i.nextInt() );
n++;
}
return n;
}
/** Pours an iterator into a type-specific collection, with a limit on the number of elements.
*
* <P>This method iterates over the given type-specific iterator and adds
* the returned elements to the given collection (up to <code>max</code>).
*
* @param i a type-specific iterator.
* @param s a type-specific collection.
* @param max the maximum number of elements to be poured.
* @return the number of elements poured. Note that
* this is the number of elements returned by the iterator, which is not necessarily the number
* of elements that have been added to the collection (because of duplicates).
*/
public static int pour( final IntIterator i, final IntCollection s, final int max ) {
if ( max < 0 ) throw new IllegalArgumentException( "The maximum number of elements (" + max + ") is negative" );
int j = max;
while( j-- != 0 && i.hasNext() ) s.add( i.nextInt() );
return max - j - 1;
}
/** Pours an iterator into a type-specific collection.
*
* <P>This method iterates over the given type-specific iterator and adds
* the returned elements to the given collection.
*
* @param i a type-specific iterator.
* @param s a type-specific collection.
* @return the number of elements poured. Note that
* this is the number of elements returned by the iterator, which is not necessarily the number
* of elements that have been added to the collection (because of duplicates).
*/
public static int pour( final IntIterator i, final IntCollection s ) {
return pour( i, s, Integer.MAX_VALUE );
}
/** Pours an iterator, returning a type-specific list, with a limit on the number of elements.
*
* <P>This method iterates over the given type-specific iterator and returns
* a type-specific list containing the returned elements (up to <code>max</code>). Iteration
* on the returned list is guaranteed to produce the elements in the same order
* in which they appeared in the iterator.
*
*
* @param i a type-specific iterator.
* @param max the maximum number of elements to be poured.
* @return a type-specific list containing the returned elements, up to <code>max</code>.
*/
public static IntList pour( final IntIterator i, int max ) {
final IntArrayList l = new IntArrayList ();
pour( i, l, max );
l.trim();
return l;
}
/** Pours an iterator, returning a type-specific list.
*
* <P>This method iterates over the given type-specific iterator and returns
* a list containing the returned elements. Iteration
* on the returned list is guaranteed to produce the elements in the same order
* in which they appeared in the iterator.
*
* @param i a type-specific iterator.
* @return a type-specific list containing the returned elements.
*/
public static IntList pour( final IntIterator i ) {
return pour( i, Integer.MAX_VALUE );
}
private static class IteratorWrapper extends AbstractIntIterator {
final Iterator<Integer> i;
public IteratorWrapper( final Iterator<Integer> i ) {
this.i = i;
}
public boolean hasNext() { return i.hasNext(); }
public void remove() { i.remove(); }
public int nextInt() { return ((i.next()).intValue()); }
}
/** Wraps a standard iterator into a type-specific iterator.
*
* <P>This method wraps a standard iterator into a type-specific one which will handle the
* type conversions for you. Of course, any attempt to wrap an iterator returning the
* instances of the wrong class will generate a {@link ClassCastException}. The
* returned iterator is backed by <code>i</code>: changes to one of the iterators
* will affect the other, too.
*
* <P>If <code>i</code> is already type-specific, it will returned and no new object
* will be generated.
*
* @param i an iterator.
* @return a type-specific iterator backed by <code>i</code>.
*/
@SuppressWarnings({ "rawtypes", "unchecked" })
public static IntIterator asIntIterator( final Iterator i ) {
if ( i instanceof IntIterator ) return (IntIterator )i;
return new IteratorWrapper ( i );
}
private static class ListIteratorWrapper extends AbstractIntListIterator {
final ListIterator<Integer> i;
public ListIteratorWrapper( final ListIterator<Integer> i ) {
this.i = i;
}
public boolean hasNext() { return i.hasNext(); }
public boolean hasPrevious() { return i.hasPrevious(); }
public int nextIndex() { return i.nextIndex(); }
public int previousIndex() { return i.previousIndex(); }
@SuppressWarnings("unchecked")
public void set( int k ) { i.set( (Integer.valueOf(k)) ); }
@SuppressWarnings("unchecked")
public void add( int k ) { i.add( (Integer.valueOf(k)) ); }
public void remove() { i.remove(); }
public int nextInt() { return ((i.next()).intValue()); }
public int previousInt() { return ((i.previous()).intValue()); }
}
/** Wraps a standard list iterator into a type-specific list iterator.
*
* <P>This method wraps a standard list iterator into a type-specific one
* which will handle the type conversions for you. Of course, any attempt
* to wrap an iterator returning the instances of the wrong class will
* generate a {@link ClassCastException}. The
* returned iterator is backed by <code>i</code>: changes to one of the iterators
* will affect the other, too.
*
* <P>If <code>i</code> is already type-specific, it will returned and no new object
* will be generated.
*
* @param i a list iterator.
* @return a type-specific list iterator backed by <code>i</code>.
*/
@SuppressWarnings({ "rawtypes", "unchecked" })
public static IntListIterator asIntIterator( final ListIterator i ) {
if ( i instanceof IntListIterator ) return (IntListIterator )i;
return new ListIteratorWrapper ( i );
}
private static class IntervalIterator extends AbstractIntListIterator {
private final int from, to;
int curr;
public IntervalIterator( final int from, final int to ) {
this.from = this.curr = from;
this.to = to;
}
public boolean hasNext() { return curr < to; }
public boolean hasPrevious() { return curr > from; }
public int nextInt() {
if ( ! hasNext() ) throw new NoSuchElementException();
return curr++;
}
public int previousInt() {
if ( ! hasPrevious() ) throw new NoSuchElementException();
return --curr;
}
public int nextIndex() { return curr - from; }
public int previousIndex() { return curr - from - 1; }
public int skip( int n ) {
if ( curr + n <= to ) {
curr += n;
return n;
}
n = to - curr;
curr = to;
return n;
}
public int back( int n ) {
if ( curr - n >= from ) {
curr -= n;
return n;
}
n = curr - from ;
curr = from;
return n;
}
}
/** Creates a type-specific list iterator over an interval.
*
* <P>The type-specific list iterator returned by this method will return the
* elements <code>from</code>, <code>from+1</code>,…, <code>to-1</code>.
*
* @param from the starting element (inclusive).
* @param to the ending element (exclusive).
* @return a type-specific list iterator enumerating the elements from <code>from</code> to <code>to</code>.
*/
public static IntListIterator fromTo( final int from, final int to ) {
return new IntervalIterator( from, to );
}
private static class IteratorConcatenator extends AbstractIntIterator {
final IntIterator a[];
int offset, length, lastOffset = -1;
public IteratorConcatenator( final IntIterator a[], int offset, int length ) {
this.a = a;
this.offset = offset;
this.length = length;
advance();
}
private void advance() {
while( length != 0 ) {
if ( a[ offset ].hasNext() ) break;
length--;
offset++;
}
return;
}
public boolean hasNext() {
return length > 0;
}
public int nextInt() {
if ( ! hasNext() ) throw new NoSuchElementException();
int next = a[ lastOffset = offset ].nextInt();
advance();
return next;
}
public void remove() {
if ( lastOffset == -1 ) throw new IllegalStateException();
a[ lastOffset ].remove();
}
public int skip( int n ) {
lastOffset = -1;
int skipped = 0;
while( skipped < n && length != 0 ) {
skipped += a[ offset ].skip( n - skipped );
if ( a[ offset ].hasNext() ) break;
length--;
offset++;
}
return skipped;
}
}
/** Concatenates all iterators contained in an array.
*
* <P>This method returns an iterator that will enumerate in order the elements returned
* by all iterators contained in the given array.
*
* @param a an array of iterators.
* @return an iterator obtained by concatenation.
*/
public static IntIterator concat( final IntIterator a[] ) {
return concat( a, 0, a.length );
}
/** Concatenates a sequence of iterators contained in an array.
*
* <P>This method returns an iterator that will enumerate in order the elements returned
* by <code>a[ offset ]</code>, then those returned
* by <code>a[ offset + 1 ]</code>, and so on up to
* <code>a[ offset + length - 1 ]</code>.
*
* @param a an array of iterators.
* @param offset the index of the first iterator to concatenate.
* @param length the number of iterators to concatenate.
* @return an iterator obtained by concatenation of <code>length</code> elements of <code>a</code> starting at <code>offset</code>.
*/
public static IntIterator concat( final IntIterator a[], final int offset, final int length ) {
return new IteratorConcatenator ( a, offset, length );
}
/** An unmodifiable wrapper class for iterators. */
public static class UnmodifiableIterator extends AbstractIntIterator {
final protected IntIterator i;
@SuppressWarnings("unchecked")
public UnmodifiableIterator( final IntIterator i ) {
this.i = i;
}
public boolean hasNext() { return i.hasNext(); }
public int nextInt() { return i.nextInt(); }
public Integer next() { return i.next(); }
}
/** Returns an unmodifiable iterator backed by the specified iterator.
*
* @param i the iterator to be wrapped in an unmodifiable iterator.
* @return an unmodifiable view of the specified iterator.
*/
public static IntIterator unmodifiable( final IntIterator i ) { return new UnmodifiableIterator ( i ); }
/** An unmodifiable wrapper class for bidirectional iterators. */
public static class UnmodifiableBidirectionalIterator extends AbstractIntBidirectionalIterator {
final protected IntBidirectionalIterator i;
@SuppressWarnings("unchecked")
public UnmodifiableBidirectionalIterator( final IntBidirectionalIterator i ) {
this.i = i;
}
public boolean hasNext() { return i.hasNext(); }
public boolean hasPrevious() { return i.hasPrevious(); }
public int nextInt() { return i.nextInt(); }
public int previousInt() { return i.previousInt(); }
public Integer next() { return i.next(); }
public Integer previous() { return i.previous(); }
}
/** Returns an unmodifiable bidirectional iterator backed by the specified bidirectional iterator.
*
* @param i the bidirectional iterator to be wrapped in an unmodifiable bidirectional iterator.
* @return an unmodifiable view of the specified bidirectional iterator.
*/
public static IntBidirectionalIterator unmodifiable( final IntBidirectionalIterator i ) { return new UnmodifiableBidirectionalIterator ( i ); }
/** An unmodifiable wrapper class for list iterators. */
public static class UnmodifiableListIterator extends AbstractIntListIterator {
final protected IntListIterator i;
@SuppressWarnings("unchecked")
public UnmodifiableListIterator( final IntListIterator i ) {
this.i = i;
}
public boolean hasNext() { return i.hasNext(); }
public boolean hasPrevious() { return i.hasPrevious(); }
public int nextInt() { return i.nextInt(); }
public int previousInt() { return i.previousInt(); }
public int nextIndex() { return i.nextIndex(); }
public int previousIndex() { return i.previousIndex(); }
public Integer next() { return i.next(); }
public Integer previous() { return i.previous(); }
}
/** Returns an unmodifiable list iterator backed by the specified list iterator.
*
* @param i the list iterator to be wrapped in an unmodifiable list iterator.
* @return an unmodifiable view of the specified list iterator.
*/
public static IntListIterator unmodifiable( final IntListIterator i ) { return new UnmodifiableListIterator ( i ); }
/** A wrapper promoting the results of a ByteIterator. */
protected static class ByteIteratorWrapper implements IntIterator {
final it.unimi.dsi.fastutil.bytes.ByteIterator iterator;
public ByteIteratorWrapper( final it.unimi.dsi.fastutil.bytes.ByteIterator iterator ) {
this.iterator = iterator;
}
public boolean hasNext() { return iterator.hasNext(); }
public Integer next() { return Integer.valueOf( iterator.nextByte() ); }
public int nextInt() { return iterator.nextByte(); }
public void remove() { iterator.remove(); }
public int skip( final int n ) { return iterator.skip( n ); }
}
/** Returns an iterator backed by the specified byte iterator.
* @return an iterator backed by the specified byte iterator.
*/
public static IntIterator wrap( final it.unimi.dsi.fastutil.bytes.ByteIterator iterator ) {
return new ByteIteratorWrapper( iterator );
}
/** A wrapper promoting the results of a ShortIterator. */
protected static class ShortIteratorWrapper implements IntIterator {
final it.unimi.dsi.fastutil.shorts.ShortIterator iterator;
public ShortIteratorWrapper( final it.unimi.dsi.fastutil.shorts.ShortIterator iterator ) {
this.iterator = iterator;
}
public boolean hasNext() { return iterator.hasNext(); }
public Integer next() { return Integer.valueOf( iterator.nextShort() ); }
public int nextInt() { return iterator.nextShort(); }
public void remove() { iterator.remove(); }
public int skip( final int n ) { return iterator.skip( n ); }
}
/** Returns an iterator backed by the specified short iterator.
* @return an iterator backed by the specified short iterator.
*/
public static IntIterator wrap( final it.unimi.dsi.fastutil.shorts.ShortIterator iterator ) {
return new ShortIteratorWrapper( iterator );
}
}