ViewVC Help

View File | Revision Log | Show Annotations | Download File | Root Listing

root/jsr166/jsr166/src/main/java/util/ArrayDeque.java

Comparing jsr166/src/main/java/util/ArrayDeque.java (file contents):
Revision 1.19 by dl, Fri Sep 16 11:15:41 2005 UTC vs.
Revision 1.23 by dl, Sat Sep 17 12:50:34 2005 UTC

#	Line 490 | Line 490 | public class ArrayDeque<E> extends Abstr
490		* @return true if elements moved backwards
491		*/
492		private boolean delete(int i) {
493	+	final E[] elements = this.elements;
494	+	final int mask = elements.length - 1;
495	+	final int h = head;
496	+	final int t = tail;
497	+	final int front = (i - h) & mask;
498	+	final int back  = (t - i) & mask;
499	+
500	+	// Invariant: head <= i < tail mod circularity
501	+	if (front >= ((t - h) & mask))
502	+	throw new ConcurrentModificationException();
503	+
504	+	// Optimize for least element motion
505	+	if (front < back) {
506	+	if (h <= i) {
507	+	System.arraycopy(elements, h, elements, h + 1, front);
508	+	} else { // Wrap around
509	+	System.arraycopy(elements, 0, elements, 1, i);
510	+	elements[0] = elements[mask];
511	+	System.arraycopy(elements, h, elements, h + 1, mask - h);
512	+	}
513	+	elements[h] = null;
514	+	head = (h + 1) & mask;
515	+	return false;
516	+	} else {
517	+	if (i < t) { // Copy the null tail as well
518	+	System.arraycopy(elements, i + 1, elements, i, back);
519	+	tail = t - 1;
520	+	} else { // Wrap around
521	+	System.arraycopy(elements, i + 1, elements, i, mask - i);
522	+	elements[mask] = elements[0];
523	+	System.arraycopy(elements, 1, elements, 0, t);
524	+	tail = (t - 1) & mask;
525	+	}
526	+	return true;
527	+	}
528	+	}
529	+
530	+	private boolean xdelete(int i) {
531		int mask = elements.length - 1;
532	+	int front = (i - head) & mask;
533	+	int back  = (tail - i) & mask;
534
535		// Invariant: head <= i < tail mod circularity
536	<	if (((i - head) & mask) >= ((tail - head) & mask))
536	>	if (front >= ((tail - head) & mask))
537		throw new ConcurrentModificationException();
538
539	<	// Case 1: Deque doesn't wrap
540	<	// Case 2: Deque does wrap and removed element is in the head portion
541	<	if (i >= head) {
542	<	System.arraycopy(elements, head, elements, head + 1, i - head);
543	<	elements[head] = null;
544	<	head = (head + 1) & mask;
539	>	// Optimize for least element motion
540	>	if (front < back) {
541	>	if (head <= i) {
542	>	System.arraycopy(elements, head, elements, head + 1, front);
543	>	} else { // Wrap around
544	>	System.arraycopy(elements, 0, elements, 1, i);
545	>	elements[0] = elements[mask];
546	>	System.arraycopy(elements, head, elements, head + 1, mask - head);
547	>	}
548	>	elements[head] = null;
549	>	head = (head + 1) & mask;
550		return false;
551	<	}
552	<
553	<	// Case 3: Deque wraps and removed element is in the tail portion
554	<	tail--;
555	<	System.arraycopy(elements, i + 1, elements, i, tail - i);
556	<	elements[tail] = null;
557	<	return true;
551	>	} else {
552	>	int t = tail;
553	>	tail = (tail - 1) & mask;
554	>	if (i < t) { // Copy the null tail as well
555	>	System.arraycopy(elements, i + 1, elements, i, back);
556	>	} else {     // Wrap around
557	>	System.arraycopy(elements, i + 1, elements, i, mask - i);
558	>	elements[mask] = elements[0];
559	>	System.arraycopy(elements, 1, elements, 0, t);
560	>	}
561	>	return true;
562	>	}
563		}
564
565		// *** Collection Methods ***

Diff Legend

–	Removed lines
+	Added lines
<	Changed lines
>	Changed lines