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/* 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.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.
	 *
	 * 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.
	 *
	 * 
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 element.
	 */
 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.
	 *
	 * 
The type-specific list iterator returned by this method will iterate
	 * length times, returning consecutive elements of the given
	 * array starting from the one with index offset.
	 *
	 * @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.
	 *
	 * 
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.
	 *
	 * 
This method iterates over the given type-specific iterator and stores the elements
	 * returned, up to a maximum of length, in the given array starting at offset.
	 * The number of actually unwrapped elements is returned (it may be less than max if
	 * the iterator emits less than max 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.
	 *
	 * 
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.
	 *
	 * This method iterates over the given type-specific iterator and returns an array
	 * containing the elements returned by the iterator. At most max 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 max).
	 */
 @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.
	 *
	 * 
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.
	 *
	 * 
This method iterates over the given type-specific iterator and stores the elements
	 * returned, up to a maximum of max, in the given type-specific collection.
	 * The number of actually unwrapped elements is returned (it may be less than max if
	 * the iterator emits less than max 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.
	 *
	 * 
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.
	 *
	 * 
This method iterates over the given type-specific iterator and adds
	 * the returned elements to the given collection (up to max).
	 *
	 * @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.
	 *
	 * 
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.
	 *
	 * 
This method iterates over the given type-specific iterator and returns
	 * a type-specific list containing the returned elements (up to max). 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 max.
	 */
 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.
	 *
	 * 
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 i;
  public IteratorWrapper( final Iterator 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.
	 *
	 * 
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 i: changes to one of the iterators
	 * will affect the other, too.
	 *
	 * 
If i 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 i.
	 */
 @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 i;
  public ListIteratorWrapper( final ListIterator 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.
	 *
	 * 
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 i: changes to one of the iterators
	 * will affect the other, too.
	 *
	 * 
If i 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 i.
	 */
 @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.
	 *
	 * 
The type-specific list iterator returned by this method will return the
	 * elements from, from+1,…, to-1.
	 *
	 * @param from the starting element (inclusive).
	 * @param to the ending element (exclusive).
	 * @return a type-specific list iterator enumerating the elements from from to to.
	 */
 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.
	 *
	 * 
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.
	 *
	 * 
This method returns an iterator that will enumerate in order the elements returned
	 * by a[ offset ], then those returned 
	 * by a[ offset + 1 ], and so on up to 
	 * a[ offset + length - 1 ]. 
	 *
	 * @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 length elements of a starting at offset.
	 */
 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 );
 }
}