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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 1.24 by dl, Sat Sep 17 13:21:19 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	<	int mask = elements.length - 1;
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 (((i - head) & mask) >= ((tail - head) & mask))
501	>	if (front >= ((t - h) & mask))
502		throw new ConcurrentModificationException();
503
504	<	// Case 1: Deque doesn't wrap
505	<	// Case 2: Deque does wrap and removed element is in the head portion
506	<	if (i >= head) {
507	<	System.arraycopy(elements, head, elements, head + 1, i - head);
508	<	elements[head] = null;
509	<	head = (head + 1) & mask;
510	<	return false;
511	<	}
512	<
513	<	// Case 3: Deque wraps and removed element is in the tail portion
514	<	tail--;
515	<	System.arraycopy(elements, i + 1, elements, i, tail - i);
516	<	elements[tail] = null;
517	<	return true;
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		// *** Collection Methods ***

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