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Comparing jsr166/src/main/java/util/ArrayDeque.java (file contents):
Revision 1.105 by jsr166, Tue Nov 1 21:42:45 2016 UTC vs.
Revision 1.106 by jsr166, Sat Nov 5 00:25:44 2016 UTC

#	Line 60 | Line 60 | import java.util.function.UnaryOperator;
60		public class ArrayDeque<E> extends AbstractCollection<E>
61		implements Deque<E>, Cloneable, Serializable
62		{
63	+	/*
64	+	* VMs excel at optimizing simple array loops where indices are
65	+	* incrementing or decrementing over a valid slice, e.g.
66	+	*
67	+	* for (int i = start; i < end; i++) ... elements[i]
68	+	*
69	+	* Because in a circular array, elements are in general stored in
70	+	* two disjoint such slices, we help the VM by writing unusual
71	+	* nested loops for all traversals over the elements.
72	+	*/
73	+
74		/**
75		* The array in which the elements of the deque are stored.
76		* We guarantee that all array cells not holding deque elements
#	Line 70 | Line 81 | public class ArrayDeque<E> extends Abstr
81		/**
82		* The index of the element at the head of the deque (which is the
83		* element that would be removed by remove() or pop()); or an
84	<	* arbitrary number 0 <= head < elements.length if the deque is empty.
84	>	* arbitrary number 0 <= head < elements.length equal to tail if
85	>	* the deque is empty.
86		*/
87		transient int head;
88
89	<	/** Number of elements in this collection. */
90	<	transient int size;
89	>	/**
90	>	* The index at which the next element would be added to the tail
91	>	* of the deque (via addLast(E), add(E), or push(E)).
92	>	*/
93	>	transient int tail;
94
95		/**
96		* The maximum size of array to allocate.
#	Line 90 | Line 105 | public class ArrayDeque<E> extends Abstr
105		*
106		* @param needed the required minimum extra capacity; must be positive
107		*/
108	<	private Object[] grow(int needed) {
108	>	private void grow(int needed) {
109		// overflow-conscious code
95	–	// checkInvariants();
110		final int oldCapacity = elements.length;
111		int newCapacity;
112	<	// Double size if small; else grow by 50%
112	>	// Double capacity if small; else grow by 50%
113		int jump = (oldCapacity < 64) ? (oldCapacity + 2) : (oldCapacity >> 1);
114		if (jump < needed
115		|| (newCapacity = (oldCapacity + jump)) - MAX_ARRAY_SIZE > 0)
116		newCapacity = newCapacity(needed, jump);
117		elements = Arrays.copyOf(elements, newCapacity);
118	<	if (oldCapacity - head < size) {
118	>	// Exceptionally, here tail == head needs to be disambiguated
119	>	if (tail < head || (tail == head && elements[head] != null)) {
120		// wrap around; slide first leg forward to end of array
121		int newSpace = newCapacity - oldCapacity;
122		System.arraycopy(elements, head,
#	Line 110 | Line 125 | public class ArrayDeque<E> extends Abstr
125		Arrays.fill(elements, head, head + newSpace, null);
126		head += newSpace;
127		}
113	–	return elements;
128		// checkInvariants();
129		}
130
#	Line 137 | Line 151 | public class ArrayDeque<E> extends Abstr
151		* @since TBD
152		*/
153		/* public */ void ensureCapacity(int minCapacity) {
154	<	if (minCapacity > elements.length)
155	<	grow(minCapacity - elements.length);
154	>	int needed;
155	>	if ((needed = (minCapacity + 1 - elements.length)) > 0)
156	>	grow(needed);
157		// checkInvariants();
158		}
159
#	Line 148 | Line 163 | public class ArrayDeque<E> extends Abstr
163		* @since TBD
164		*/
165		/* public */ void trimToSize() {
166	<	if (size < elements.length) {
167	<	elements = toArray();
166	>	int size;
167	>	if ((size = size()) + 1 < elements.length) {
168	>	elements = toArray(new Object[size + 1]);
169		head = 0;
170	+	tail = size;
171		}
172		// checkInvariants();
173		}
#	Line 170 | Line 187 | public class ArrayDeque<E> extends Abstr
187		* @param numElements lower bound on initial capacity of the deque
188		*/
189		public ArrayDeque(int numElements) {
190	<	elements = new Object[numElements];
190	>	elements = new Object[Math.max(1, numElements + 1)];
191		}
192
193		/**
#	Line 184 | Line 201 | public class ArrayDeque<E> extends Abstr
201		* @throws NullPointerException if the specified collection is null
202		*/
203		public ArrayDeque(Collection<? extends E> c) {
204	<	Object[] es = c.toArray();
205	<	// defend against c.toArray (incorrectly) not returning Object[]
189	<	// (see e.g. https://bugs.openjdk.java.net/browse/JDK-6260652)
190	<	if (es.getClass() != Object[].class)
191	<	es = Arrays.copyOf(es, es.length, Object[].class);
192	<	for (Object obj : es)
193	<	Objects.requireNonNull(obj);
194	<	this.elements = es;
195	<	this.size = es.length;
204	>	elements = new Object[c.size() + 1];
205	>	addAll(c);
206		}
207
208		/**
#	Line 223 | Line 233 | public class ArrayDeque<E> extends Abstr
233		}
234
235		/**
236	+	* Subtracts j from i, mod modulus.
237	+	* Index i must be logically ahead of j.
238	+	* Returns the "circular distance" from j to i.
239	+	* Precondition and postcondition: 0 <= i < modulus, 0 <= j < modulus.
240	+	*/
241	+	static final int sub(int i, int j, int modulus) {
242	+	if ((i -= j) < 0) i += modulus;
243	+	return i;
244	+	}
245	+
246	+	/**
247		* Returns the array index of the last element.
248		* May return invalid index -1 if there are no elements.
249		*/
250	<	final int tail() {
251	<	return add(head, size - 1, elements.length);
250	>	final int last() {
251	>	return dec(tail, elements.length);
252		}
253
254		/**
255		* Returns element at array index i.
256	+	* This is a slight abuse of generics, accepted by javac.
257		*/
258		@SuppressWarnings("unchecked")
259	<	private E elementAt(int i) {
260	<	return (E) elements[i];
259	>	static final <E> E elementAt(Object[] es, int i) {
260	>	return (E) es[i];
261		}
262
263		/**
264		* A version of elementAt that checks for null elements.
265		* This check doesn't catch all possible comodifications,
266	<	* but does catch ones that corrupt traversal.  It's a little
245	<	* surprising that javac allows this abuse of generics.
266	>	* but does catch ones that corrupt traversal.
267		*/
268		static final <E> E nonNullElementAt(Object[] es, int i) {
269		@SuppressWarnings("unchecked") E e = (E) es[i];
#	Line 262 | Line 283 | public class ArrayDeque<E> extends Abstr
283		* @throws NullPointerException if the specified element is null
284		*/
285		public void addFirst(E e) {
286	<	// checkInvariants();
287	<	Objects.requireNonNull(e);
288	<	Object[] es;
289	<	int capacity, h;
290	<	final int s;
291	<	if ((s = size) == (capacity = (es = elements).length))
271	<	capacity = (es = grow(1)).length;
272	<	if ((h = head - 1) < 0) h = capacity - 1;
273	<	es[head = h] = e;
274	<	size = s + 1;
286	>	if (e == null)
287	>	throw new NullPointerException();
288	>	final Object[] es = elements;
289	>	es[head = dec(head, es.length)] = e;
290	>	if (head == tail)
291	>	grow(1);
292		// checkInvariants();
293		}
294
#	Line 284 | Line 301 | public class ArrayDeque<E> extends Abstr
301		* @throws NullPointerException if the specified element is null
302		*/
303		public void addLast(E e) {
304	<	// checkInvariants();
305	<	Objects.requireNonNull(e);
306	<	Object[] es;
307	<	int capacity;
308	<	final int s;
309	<	if ((s = size) == (capacity = (es = elements).length))
293	<	capacity = (es = grow(1)).length;
294	<	es[add(head, s, capacity)] = e;
295	<	size = s + 1;
304	>	if (e == null)
305	>	throw new NullPointerException();
306	>	final Object[] es = elements;
307	>	es[tail] = e;
308	>	if (head == (tail = inc(tail, es.length)))
309	>	grow(1);
310		// checkInvariants();
311		}
312
#	Line 308 | Line 322 | public class ArrayDeque<E> extends Abstr
322		*         of its elements are null
323		*/
324		public boolean addAll(Collection<? extends E> c) {
325	<	final int s = size, needed = c.size() - (elements.length - s);
326	<	if (needed > 0)
325	>	final int s = size(), needed;
326	>	if ((needed = s + c.size() - elements.length + 1) > 0)
327		grow(needed);
328		c.forEach((e) -> addLast(e));
329		// checkInvariants();
330	<	return size > s;
330	>	return size() > s;
331		}
332
333		/**
#	Line 344 | Line 358 | public class ArrayDeque<E> extends Abstr
358		* @throws NoSuchElementException {@inheritDoc}
359		*/
360		public E removeFirst() {
347	–	// checkInvariants();
361		E e = pollFirst();
362		if (e == null)
363		throw new NoSuchElementException();
364	+	// checkInvariants();
365		return e;
366		}
367
#	Line 355 | Line 369 | public class ArrayDeque<E> extends Abstr
369		* @throws NoSuchElementException {@inheritDoc}
370		*/
371		public E removeLast() {
358	–	// checkInvariants();
372		E e = pollLast();
373		if (e == null)
374		throw new NoSuchElementException();
375	+	// checkInvariants();
376		return e;
377		}
378
379		public E pollFirst() {
380	+	final Object[] es;
381	+	final int h;
382	+	E e = elementAt(es = elements, h = head);
383	+	if (e != null) {
384	+	es[h] = null;
385	+	head = inc(h, es.length);
386	+	}
387		// checkInvariants();
367	–	int s, h;
368	–	if ((s = size) <= 0)
369	–	return null;
370	–	final Object[] es = elements;
371	–	@SuppressWarnings("unchecked") E e = (E) es[h = head];
372	–	es[h] = null;
373	–	if (++h >= es.length) h = 0;
374	–	head = h;
375	–	size = s - 1;
388		return e;
389		}
390
391		public E pollLast() {
392	+	final Object[] es;
393	+	final int t;
394	+	E e = elementAt(es = elements, t = dec(tail, es.length));
395	+	if (e != null)
396	+	es[tail = t] = null;
397		// checkInvariants();
381	–	final int s, tail;
382	–	if ((s = size) <= 0)
383	–	return null;
384	–	final Object[] es = elements;
385	–	@SuppressWarnings("unchecked")
386	–	E e = (E) es[tail = add(head, s - 1, es.length)];
387	–	es[tail] = null;
388	–	size = s - 1;
398		return e;
399		}
400
#	Line 393 | Line 402 | public class ArrayDeque<E> extends Abstr
402		* @throws NoSuchElementException {@inheritDoc}
403		*/
404		public E getFirst() {
405	+	E e = elementAt(elements, head);
406	+	if (e == null)
407	+	throw new NoSuchElementException();
408		// checkInvariants();
409	<	if (size <= 0) throw new NoSuchElementException();
398	<	return elementAt(head);
409	>	return e;
410		}
411
412		/**
413		* @throws NoSuchElementException {@inheritDoc}
414		*/
404	–	@SuppressWarnings("unchecked")
415		public E getLast() {
406	–	// checkInvariants();
407	–	final int s;
408	–	if ((s = size) <= 0) throw new NoSuchElementException();
416		final Object[] es = elements;
417	<	return (E) es[add(head, s - 1, es.length)];
417	>	E e = elementAt(es, dec(tail, es.length));
418	>	if (e == null)
419	>	throw new NoSuchElementException();
420	>	// checkInvariants();
421	>	return e;
422		}
423
424		public E peekFirst() {
425		// checkInvariants();
426	<	return (size <= 0) ? null : elementAt(head);
426	>	return elementAt(elements, head);
427		}
428
418	–	@SuppressWarnings("unchecked")
429		public E peekLast() {
430		// checkInvariants();
431	<	final int s;
432	<	if ((s = size) <= 0) return null;
423	<	final Object[] es = elements;
424	<	return (E) es[add(head, s - 1, es.length)];
431	>	final Object[] es;
432	>	return elementAt(es = elements, dec(tail, es.length));
433		}
434
435		/**
#	Line 439 | Line 447 | public class ArrayDeque<E> extends Abstr
447		public boolean removeFirstOccurrence(Object o) {
448		if (o != null) {
449		final Object[] es = elements;
450	<	int i, end, to, todo;
451	<	todo = (end = (i = head) + size)
444	<	- (to = (es.length - end >= 0) ? end : es.length);
445	<	for (;; to = todo, todo = 0, i = 0) {
450	>	for (int i = head, end = tail, to = (i <= end) ? end : es.length;
451	>	; i = 0, to = end) {
452		for (; i < to; i++)
453		if (o.equals(es[i])) {
454		delete(i);
455		return true;
456		}
457	<	if (todo == 0) break;
457	>	if (to == end) break;
458		}
459		}
460		return false;
#	Line 469 | Line 475 | public class ArrayDeque<E> extends Abstr
475		public boolean removeLastOccurrence(Object o) {
476		if (o != null) {
477		final Object[] es = elements;
478	<	int i, to, end, todo;
479	<	todo = (to = ((end = (i = tail()) - size) >= -1) ? end : -1) - end;
474	<	for (;; to = (i = es.length - 1) - todo, todo = 0) {
478	>	for (int i = last(), end = head - 1, to = (i >= end) ? end : -1;
479	>	; i = es.length - 1, to = end) {
480		for (; i > to; i--)
481		if (o.equals(es[i])) {
482		delete(i);
483		return true;
484		}
485	<	if (todo == 0) break;
485	>	if (to == end) break;
486		}
487		}
488		return false;
#	Line 605 | Line 610 | public class ArrayDeque<E> extends Abstr
610		* <p>This method is called delete rather than remove to emphasize
611		* that its semantics differ from those of {@link List#remove(int)}.
612		*
613	<	* @return true if elements moved backwards
613	>	* @return true if elements near tail moved backwards
614		*/
615		boolean delete(int i) {
616		// checkInvariants();
617		final Object[] es = elements;
618		final int capacity = es.length;
619		final int h = head;
620	<	int front;              // number of elements before to-be-deleted elt
621	<	if ((front = i - h) < 0) front += capacity;
622	<	final int back = size - front - 1; // number of elements after
620	>	// number of elements before to-be-deleted elt
621	>	final int front = sub(i, h, capacity);
622	>	final int back = size() - front - 1; // number of elements after
623		if (front < back) {
624		// move front elements forwards
625		if (h <= i) {
#	Line 625 | Line 630 | public class ArrayDeque<E> extends Abstr
630		System.arraycopy(es, h, es, h + 1, front - (i + 1));
631		}
632		es[h] = null;
633	<	if ((head = (h + 1)) >= capacity) head = 0;
629	<	size--;
633	>	head = inc(h, capacity);
634		// checkInvariants();
635		return false;
636		} else {
637		// move back elements backwards
638	<	int tail = tail();
638	>	tail = dec(tail, capacity);
639		if (i <= tail) {
640		System.arraycopy(es, i + 1, es, i, back);
641		} else { // Wrap around
#	Line 641 | Line 645 | public class ArrayDeque<E> extends Abstr
645		System.arraycopy(es, 1, es, 0, back - firstLeg - 1);
646		}
647		es[tail] = null;
644	–	size--;
648		// checkInvariants();
649		return true;
650		}
#	Line 655 | Line 658 | public class ArrayDeque<E> extends Abstr
658		* @return the number of elements in this deque
659		*/
660		public int size() {
661	<	return size;
661	>	return sub(tail, head, elements.length);
662		}
663
664		/**
#	Line 664 | Line 667 | public class ArrayDeque<E> extends Abstr
667		* @return {@code true} if this deque contains no elements
668		*/
669		public boolean isEmpty() {
670	<	return size == 0;
670	>	return head == tail;
671		}
672
673		/**
#	Line 688 | Line 691 | public class ArrayDeque<E> extends Abstr
691		int cursor;
692
693		/** Number of elements yet to be returned. */
694	<	int remaining = size;
694	>	int remaining = size();
695
696		/**
697		* Index of element returned by most recent call to next.
#	Line 708 | Line 711 | public class ArrayDeque<E> extends Abstr
711		final Object[] es = elements;
712		E e = nonNullElementAt(es, cursor);
713		lastRet = cursor;
714	<	if (++cursor >= es.length) cursor = 0;
714	>	cursor = inc(cursor, es.length);
715		remaining--;
716		return e;
717		}
718
719		void postDelete(boolean leftShifted) {
720		if (leftShifted)
721	<	if (--cursor < 0) cursor = elements.length - 1;
721	>	cursor = dec(cursor, elements.length);
722		}
723
724		public final void remove() {
#	Line 727 | Line 730 | public class ArrayDeque<E> extends Abstr
730
731		public void forEachRemaining(Consumer<? super E> action) {
732		Objects.requireNonNull(action);
733	<	final int k;
734	<	if ((k = remaining) > 0) {
735	<	remaining = 0;
736	<	ArrayDeque.forEachRemaining(action, elements, cursor, k);
737	<	if ((lastRet = cursor + k - 1) >= elements.length)
738	<	lastRet -= elements.length;
733	>	int r;
734	>	if ((r = remaining) <= 0)
735	>	return;
736	>	remaining = 0;
737	>	final Object[] es = elements;
738	>	if (es[cursor] == null || sub(tail, cursor, es.length) != r)
739	>	throw new ConcurrentModificationException();
740	>	for (int i = cursor, end = tail, to = (i <= end) ? end : es.length;
741	>	; i = 0, to = end) {
742	>	for (; i < to; i++)
743	>	action.accept(elementAt(es, i));
744	>	if (to == end) {
745	>	if (end != tail)
746	>	throw new ConcurrentModificationException();
747	>	lastRet = dec(end, es.length);
748	>	break;
749	>	}
750		}
751		}
752		}
753
754		private class DescendingIterator extends DeqIterator {
755	<	DescendingIterator() { cursor = tail(); }
755	>	DescendingIterator() { cursor = last(); }
756
757		public final E next() {
758		if (remaining <= 0)
#	Line 746 | Line 760 | public class ArrayDeque<E> extends Abstr
760		final Object[] es = elements;
761		E e = nonNullElementAt(es, cursor);
762		lastRet = cursor;
763	<	if (--cursor < 0) cursor = es.length - 1;
763	>	cursor = dec(cursor, es.length);
764		remaining--;
765		return e;
766		}
767
768		void postDelete(boolean leftShifted) {
769		if (!leftShifted)
770	<	if (++cursor >= elements.length) cursor = 0;
770	>	cursor = inc(cursor, elements.length);
771		}
772
773		public final void forEachRemaining(Consumer<? super E> action) {
774		Objects.requireNonNull(action);
775	<	final int k;
776	<	if ((k = remaining) > 0) {
777	<	remaining = 0;
778	<	final Object[] es = elements;
779	<	int i, end, to, todo;
780	<	todo = (to = ((end = (i = cursor) - k) >= -1) ? end : -1) - end;
781	<	for (;; to = (i = es.length - 1) - todo, todo = 0) {
782	<	for (; i > to; i--)
783	<	action.accept(nonNullElementAt(es, i));
784	<	if (todo == 0) break;
775	>	int r;
776	>	if ((r = remaining) <= 0)
777	>	return;
778	>	remaining = 0;
779	>	final Object[] es = elements;
780	>	if (es[cursor] == null || sub(cursor, head, es.length) + 1 != r)
781	>	throw new ConcurrentModificationException();
782	>	for (int i = cursor, end = head - 1, to = (i >= end) ? end : -1;
783	>	; i = es.length - 1, to = end) {
784	>	for (; i > to; i--)
785	>	action.accept(elementAt(es, i));
786	>	if (to == end) {
787	>	if (end != head - 1)
788	>	throw new ConcurrentModificationException();
789	>	lastRet = head;
790	>	break;
791		}
772	–	if ((lastRet = cursor - (k - 1)) < 0)
773	–	lastRet += es.length;
792		}
793		}
794		}
#	Line 789 | Line 807 | public class ArrayDeque<E> extends Abstr
807		* @since 1.8
808		*/
809		public Spliterator<E> spliterator() {
810	<	return new ArrayDequeSpliterator();
810	>	return new DeqSpliterator();
811		}
812
813	<	final class ArrayDequeSpliterator implements Spliterator<E> {
814	<	private int cursor;
815	<	private int remaining; // -1 until late-binding first use
813	>	final class DeqSpliterator implements Spliterator<E> {
814	>	private int fence;      // -1 until first use
815	>	private int cursor;     // current index, modified on traverse/split
816
817		/** Constructs late-binding spliterator over all elements. */
818	<	ArrayDequeSpliterator() {
819	<	this.remaining = -1;
818	>	DeqSpliterator() {
819	>	this.fence = -1;
820		}
821
822	<	/** Constructs spliterator over the given slice. */
823	<	ArrayDequeSpliterator(int cursor, int count) {
824	<	this.cursor = cursor;
825	<	this.remaining = count;
822	>	/** Constructs spliterator over the given range. */
823	>	DeqSpliterator(int origin, int fence) {
824	>	this.cursor = origin;
825	>	this.fence = fence;
826		}
827
828	<	/** Ensures late-binding initialization; then returns remaining. */
829	<	private int remaining() {
830	<	if (remaining < 0) {
828	>	/** Ensures late-binding initialization; then returns fence. */
829	>	private int getFence() { // force initialization
830	>	int t;
831	>	if ((t = fence) < 0) {
832	>	t = fence = tail;
833		cursor = head;
814	–	remaining = size;
834		}
835	<	return remaining;
835	>	return t;
836		}
837
838	<	public ArrayDequeSpliterator trySplit() {
839	<	final int mid;
840	<	if ((mid = remaining() >> 1) > 0) {
841	<	int oldCursor = cursor;
842	<	cursor = add(cursor, mid, elements.length);
843	<	remaining -= mid;
825	<	return new ArrayDequeSpliterator(oldCursor, mid);
826	<	}
827	<	return null;
838	>	public DeqSpliterator trySplit() {
839	>	final Object[] es = elements;
840	>	final int i, n;
841	>	return ((n = sub(getFence(), i = cursor, es.length) >> 1) <= 0)
842	>	? null
843	>	: new DeqSpliterator(i, cursor = add(i, n, es.length));
844		}
845
846		public void forEachRemaining(Consumer<? super E> action) {
847	<	Objects.requireNonNull(action);
848	<	final int k = remaining(); // side effect!
849	<	remaining = 0;
850	<	ArrayDeque.forEachRemaining(action, elements, cursor, k);
847	>	if (action == null)
848	>	throw new NullPointerException();
849	>	final int end = getFence(), cursor = this.cursor;
850	>	final Object[] es = elements;
851	>	if (cursor != end) {
852	>	this.cursor = end;
853	>	// null check at both ends of range is sufficient
854	>	if (es[cursor] == null || es[dec(end, es.length)] == null)
855	>	throw new ConcurrentModificationException();
856	>	for (int i = cursor, to = (i <= end) ? end : es.length;
857	>	; i = 0, to = end) {
858	>	for (; i < to; i++)
859	>	action.accept(elementAt(es, i));
860	>	if (to == end) break;
861	>	}
862	>	}
863		}
864
865		public boolean tryAdvance(Consumer<? super E> action) {
866	<	Objects.requireNonNull(action);
867	<	final int k;
868	<	if ((k = remaining()) <= 0)
866	>	if (action == null)
867	>	throw new NullPointerException();
868	>	int t, i;
869	>	if ((t = fence) < 0) t = getFence();
870	>	if (t == (i = cursor))
871		return false;
872	<	action.accept(nonNullElementAt(elements, cursor));
873	<	if (++cursor >= elements.length) cursor = 0;
874	<	remaining = k - 1;
872	>	final Object[] es;
873	>	action.accept(nonNullElementAt(es = elements, i));
874	>	cursor = inc(i, es.length);
875		return true;
876		}
877
878		public long estimateSize() {
879	<	return remaining();
879	>	return sub(getFence(), cursor, elements.length);
880		}
881
882		public int characteristics() {
#	Line 857 | Line 887 | public class ArrayDeque<E> extends Abstr
887		}
888		}
889
860	–	@SuppressWarnings("unchecked")
890		public void forEach(Consumer<? super E> action) {
891		Objects.requireNonNull(action);
892		final Object[] es = elements;
893	<	int i, end, to, todo;
894	<	todo = (end = (i = head) + size)
866	<	- (to = (es.length - end >= 0) ? end : es.length);
867	<	for (;; to = todo, todo = 0, i = 0) {
893	>	for (int i = head, end = tail, to = (i <= end) ? end : es.length;
894	>	; i = 0, to = end) {
895		for (; i < to; i++)
896	<	action.accept((E) es[i]);
897	<	if (todo == 0) break;
896	>	action.accept(elementAt(es, i));
897	>	if (to == end) {
898	>	if (end != tail) throw new ConcurrentModificationException();
899	>	break;
900	>	}
901		}
902		// checkInvariants();
903		}
904
905		/**
876	–	* Calls action on remaining elements, starting at index i and
877	–	* traversing in ascending order.  A variant of forEach that also
878	–	* checks for concurrent modification, for use in iterators.
879	–	*/
880	–	static <E> void forEachRemaining(
881	–	Consumer<? super E> action, Object[] es, int i, int remaining) {
882	–	int end, to, todo;
883	–	todo = (end = i + remaining)
884	–	- (to = (es.length - end >= 0) ? end : es.length);
885	–	for (;; to = todo, todo = 0, i = 0) {
886	–	for (; i < to; i++)
887	–	action.accept(nonNullElementAt(es, i));
888	–	if (todo == 0) break;
889	–	}
890	–	}
891	–
892	–	/**
906		* Replaces each element of this deque with the result of applying the
907		* operator to that element, as specified by {@link List#replaceAll}.
908		*
909		* @param operator the operator to apply to each element
910		* @since TBD
911		*/
899	–	@SuppressWarnings("unchecked")
912		/* public */ void replaceAll(UnaryOperator<E> operator) {
913		Objects.requireNonNull(operator);
914		final Object[] es = elements;
915	<	int i, end, to, todo;
916	<	todo = (end = (i = head) + size)
905	<	- (to = (es.length - end >= 0) ? end : es.length);
906	<	for (;; to = todo, todo = 0, i = 0) {
915	>	for (int i = head, end = tail, to = (i <= end) ? end : es.length;
916	>	; i = 0, to = end) {
917		for (; i < to; i++)
918	<	es[i] = operator.apply((E) es[i]);
919	<	if (todo == 0) break;
918	>	es[i] = operator.apply(elementAt(es, i));
919	>	if (to == end) {
920	>	if (end != tail) throw new ConcurrentModificationException();
921	>	break;
922	>	}
923		}
924		// checkInvariants();
925		}
#	Line 936 | Line 949 | public class ArrayDeque<E> extends Abstr
949		}
950
951		/** Implementation of bulk remove methods. */
939	–	@SuppressWarnings("unchecked")
952		private boolean bulkRemove(Predicate<? super E> filter) {
953		// checkInvariants();
954		final Object[] es = elements;
955	<	int i, end, to, todo;
956	<	todo = (end = (i = head) + size)
957	<	- (to = (es.length - end >= 0) ? end : es.length);
946	<	// Optimize for initial run of non-removed elements
947	<	findFirstRemoved:
948	<	for (;; to = todo, todo = 0, i = 0) {
955	>	// Optimize for initial run of survivors
956	>	for (int i = head, end = tail, to = (i <= end) ? end : es.length;
957	>	; i = 0, to = end) {
958		for (; i < to; i++)
959	<	if (filter.test((E) es[i]))
960	<	break findFirstRemoved;
961	<	if (todo == 0) return false;
959	>	if (filter.test(elementAt(es, i)))
960	>	return bulkRemoveModified(filter, i, to);
961	>	if (to == end) {
962	>	if (end != tail) throw new ConcurrentModificationException();
963	>	break;
964	>	}
965		}
966	<	bulkRemoveModified(filter, i, to, todo);
955	<	return true;
966	>	return false;
967		}
968
969		/**
970		* Helper for bulkRemove, in case of at least one deletion.
971		* @param i valid index of first element to be deleted
972		*/
973	<	@SuppressWarnings("unchecked")
974	<	private void bulkRemoveModified(
964	<	Predicate<? super E> filter, int i, int to, int todo) {
973	>	private boolean bulkRemoveModified(
974	>	Predicate<? super E> filter, int i, int to) {
975		final Object[] es = elements;
976		final int capacity = es.length;
977	<	// a two-finger algorithm, with hare i and tortoise j
977	>	// a two-finger algorithm, with hare i reading, tortoise j writing
978		int j = i++;
979	+	final int end = tail;
980		try {
981	<	for (;;) {
981	>	for (;; j = 0) {    // j rejoins i on second leg
982		E e;
983		// In this loop, i and j are on the same leg, with i > j
984		for (; i < to; i++)
985	<	if (!filter.test(e = (E) es[i]))
985	>	if (!filter.test(e = elementAt(es, i)))
986		es[j++] = e;
987	<	if (todo == 0) break;
987	>	if (to == end) break;
988		// In this loop, j is on the first leg, i on the second
989	<	for (to = todo, todo = 0, i = 0; i < to && j < capacity; i++)
990	<	if (!filter.test(e = (E) es[i]))
989	>	for (i = 0, to = end; i < to && j < capacity; i++)
990	>	if (!filter.test(e = elementAt(es, i)))
991		es[j++] = e;
992	<	if (i >= to) break;
993	<	j = 0;          // j rejoins i on second leg
992	>	if (i >= to) {
993	>	if (j == capacity) j = 0; // "corner" case
994	>	break;
995	>	}
996		}
997	<	bulkRemoveClear(es, j, i);
985	<	// checkInvariants();
997	>	return true;
998		} catch (Throwable ex) {
999		// copy remaining elements
1000	<	for (int remaining = (to - i) + todo; --remaining >= 0;) {
1000	>	for (; i != end; i = inc(i, capacity), j = inc(j, capacity))
1001		es[j] = es[i];
990	–	if (++i >= capacity) i = 0;
991	–	if (++j >= capacity) j = 0;
992	–	}
993	–	bulkRemoveClear(es, j, i);
994	–	// checkInvariants();
1002		throw ex;
1003	+	} finally {
1004	+	if (end != tail) throw new ConcurrentModificationException();
1005	+	circularClear(es, tail = j, end);
1006	+	// checkInvariants();
1007		}
1008		}
1009
1010		/**
1000	–	* Nulls out all elements from index j upto index i.
1001	–	*/
1002	–	private void bulkRemoveClear(Object[] es, int j, int i) {
1003	–	int deleted;
1004	–	if ((deleted = i - j) <= 0) deleted += es.length;
1005	–	size -= deleted;
1006	–	circularClear(es, j, deleted);
1007	–	}
1008	–
1009	–	/**
1011		* Returns {@code true} if this deque contains the specified element.
1012		* More formally, returns {@code true} if and only if this deque contains
1013		* at least one element {@code e} such that {@code o.equals(e)}.
#	Line 1017 | Line 1018 | public class ArrayDeque<E> extends Abstr
1018		public boolean contains(Object o) {
1019		if (o != null) {
1020		final Object[] es = elements;
1021	<	int i, end, to, todo;
1022	<	todo = (end = (i = head) + size)
1022	<	- (to = (es.length - end >= 0) ? end : es.length);
1023	<	for (;; to = todo, todo = 0, i = 0) {
1021	>	for (int i = head, end = tail, to = (i <= end) ? end : es.length;
1022	>	; i = 0, to = end) {
1023		for (; i < to; i++)
1024		if (o.equals(es[i]))
1025		return true;
1026	<	if (todo == 0) break;
1026	>	if (to == end) break;
1027		}
1028		}
1029		return false;
#	Line 1052 | Line 1051 | public class ArrayDeque<E> extends Abstr
1051		* The deque will be empty after this call returns.
1052		*/
1053		public void clear() {
1054	<	circularClear(elements, head, size);
1055	<	size = head = 0;
1054	>	circularClear(elements, head, tail);
1055	>	head = tail = 0;
1056		// checkInvariants();
1057		}
1058
1059		/**
1060	<	* Nulls out count elements, starting at array index from.
1062	<	* Special case (from == es.length) is treated the same as (from == 0).
1060	>	* Nulls out slots starting at array index i, upto index end.
1061		*/
1062	<	private static void circularClear(Object[] es, int from, int count) {
1063	<	int end, to, todo;
1064	<	todo = (end = from + count)
1065	<	- (to = (es.length - end >= 0) ? end : es.length);
1066	<	for (;; to = todo, todo = 0, from = 0) {
1069	<	Arrays.fill(es, from, to, null);
1070	<	if (todo == 0) break;
1062	>	private static void circularClear(Object[] es, int i, int end) {
1063	>	for (int to = (i <= end) ? end : es.length;
1064	>	; i = 0, to = end) {
1065	>	Arrays.fill(es, i, to, null);
1066	>	if (to == end) break;
1067		}
1068		}
1069
#	Line 1091 | Line 1087 | public class ArrayDeque<E> extends Abstr
1087		private <T> T[] toArray(Class<T[]> klazz) {
1088		final Object[] es = elements;
1089		final T[] a;
1090	<	final int head, len, end, todo;
1091	<	todo = size - (len = Math.min(size, es.length - (head = this.head)));
1090	>	final int size = size(), head = this.head, end;
1091	>	final int len = Math.min(size, es.length - head);
1092		if ((end = head + size) >= 0) {
1093		a = Arrays.copyOfRange(es, head, end, klazz);
1094		} else {
#	Line 1100 | Line 1096 | public class ArrayDeque<E> extends Abstr
1096		a = Arrays.copyOfRange(es, 0, size, klazz);
1097		System.arraycopy(es, head, a, 0, len);
1098		}
1099	<	if (todo > 0)
1100	<	System.arraycopy(es, 0, a, len, todo);
1099	>	if (tail < head)
1100	>	System.arraycopy(es, 0, a, len, tail);
1101		return a;
1102		}
1103
#	Line 1144 | Line 1140 | public class ArrayDeque<E> extends Abstr
1140		@SuppressWarnings("unchecked")
1141		public <T> T[] toArray(T[] a) {
1142		final int size;
1143	<	if ((size = this.size) > a.length)
1143	>	if ((size = size()) > a.length)
1144		return toArray((Class<T[]>) a.getClass());
1145		final Object[] es = elements;
1146	<	int i, j, len, todo;
1147	<	todo = size - (len = Math.min(size, es.length - (i = head)));
1152	<	for (j = 0;; j += len, len = todo, todo = 0, i = 0) {
1146	>	for (int i = head, j = 0, len = Math.min(size, es.length - i);
1147	>	; i = 0, len = tail) {
1148		System.arraycopy(es, i, a, j, len);
1149	<	if (todo == 0) break;
1149	>	if ((j += len) == size) break;
1150		}
1151		if (size < a.length)
1152		a[size] = null;
#	Line 1192 | Line 1187 | public class ArrayDeque<E> extends Abstr
1187		s.defaultWriteObject();
1188
1189		// Write out size
1190	<	s.writeInt(size);
1190	>	s.writeInt(size());
1191
1192		// Write out elements in order.
1193		final Object[] es = elements;
1194	<	int i, end, to, todo;
1195	<	todo = (end = (i = head) + size)
1201	<	- (to = (es.length - end >= 0) ? end : es.length);
1202	<	for (;; to = todo, todo = 0, i = 0) {
1194	>	for (int i = head, end = tail, to = (i <= end) ? end : es.length;
1195	>	; i = 0, to = end) {
1196		for (; i < to; i++)
1197		s.writeObject(es[i]);
1198	<	if (todo == 0) break;
1198	>	if (to == end) break;
1199		}
1200		}
1201
#	Line 1218 | Line 1211 | public class ArrayDeque<E> extends Abstr
1211		s.defaultReadObject();
1212
1213		// Read in size and allocate array
1214	<	elements = new Object[size = s.readInt()];
1214	>	int size = s.readInt();
1215	>	elements = new Object[size + 1];
1216	>	this.tail = size;
1217
1218		// Read in all elements in the proper order.
1219		for (int i = 0; i < size; i++)
#	Line 1229 | Line 1224 | public class ArrayDeque<E> extends Abstr
1224		void checkInvariants() {
1225		try {
1226		int capacity = elements.length;
1227	<	// assert size >= 0 && size <= capacity;
1228	<	// assert head >= 0;
1229	<	// assert capacity == 0 || head < capacity;
1230	<	// assert size == 0 || elements[head] != null;
1231	<	// assert size == 0 || elements[tail()] != null;
1232	<	// assert size == capacity || elements[dec(head, capacity)] == null;
1233	<	// assert size == capacity || elements[inc(tail(), capacity)] == null;
1227	>	// assert head >= 0 && head < capacity;
1228	>	// assert tail >= 0 && tail < capacity;
1229	>	// assert capacity > 0;
1230	>	// assert size() < capacity;
1231	>	// assert head == tail || elements[head] != null;
1232	>	// assert elements[tail] == null;
1233	>	// assert head == tail || elements[dec(tail, capacity)] != null;
1234		} catch (Throwable t) {
1235	<	System.err.printf("head=%d size=%d capacity=%d%n",
1236	<	head, size, elements.length);
1235	>	System.err.printf("head=%d tail=%d capacity=%d%n",
1236	>	head, tail, elements.length);
1237		System.err.printf("elements=%s%n",
1238		Arrays.toString(elements));
1239		throw t;

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