--- jsr166/src/main/java/util/ArrayDeque.java 2016/11/20 15:49:25 1.120
+++ jsr166/src/main/java/util/ArrayDeque.java 2017/05/31 19:01:08 1.129
@@ -50,7 +50,7 @@ import java.util.function.UnaryOperator;
* Iterator} interfaces.
*
*
This class is a member of the
- *
+ *
* Java Collections Framework.
*
* @author Josh Bloch and Doug Lea
@@ -117,16 +117,16 @@ public class ArrayDeque extends Abstr
if (jump < needed
|| (newCapacity = (oldCapacity + jump)) - MAX_ARRAY_SIZE > 0)
newCapacity = newCapacity(needed, jump);
- elements = Arrays.copyOf(elements, newCapacity);
+ final Object[] es = elements = Arrays.copyOf(elements, newCapacity);
// Exceptionally, here tail == head needs to be disambiguated
- if (tail < head || (tail == head && elements[head] != null)) {
+ if (tail < head || (tail == head && es[head] != null)) {
// wrap around; slide first leg forward to end of array
int newSpace = newCapacity - oldCapacity;
- System.arraycopy(elements, head,
- elements, head + newSpace,
+ System.arraycopy(es, head,
+ es, head + newSpace,
oldCapacity - head);
- Arrays.fill(elements, head, head + newSpace, null);
- head += newSpace;
+ for (int i = head, to = (head += newSpace); i < to; i++)
+ es[i] = null;
}
// checkInvariants();
}
@@ -235,7 +235,7 @@ public class ArrayDeque extends Abstr
* @return index 0 <= i < modulus
*/
static final int add(int i, int distance, int modulus) {
- if ((i += distance) - modulus >= 0) distance -= modulus;
+ if ((i += distance) - modulus >= 0) i -= modulus;
return i;
}
@@ -313,8 +313,7 @@ public class ArrayDeque extends Abstr
/**
* Adds all of the elements in the specified collection at the end
* of this deque, as if by calling {@link #addLast} on each one,
- * in the order that they are returned by the collection's
- * iterator.
+ * in the order that they are returned by the collection's iterator.
*
* @param c the elements to be inserted into this deque
* @return {@code true} if this deque changed as a result of the call
@@ -520,8 +519,8 @@ public class ArrayDeque extends Abstr
/**
* Retrieves and removes the head of the queue represented by this deque.
*
- * This method differs from {@link #poll poll} only in that it throws an
- * exception if this deque is empty.
+ * This method differs from {@link #poll() poll()} only in that it
+ * throws an exception if this deque is empty.
*
* This method is equivalent to {@link #removeFirst}.
*
@@ -710,8 +709,7 @@ public class ArrayDeque extends Abstr
throw new NoSuchElementException();
final Object[] es = elements;
E e = nonNullElementAt(es, cursor);
- lastRet = cursor;
- cursor = inc(cursor, es.length);
+ cursor = inc(lastRet = cursor, es.length);
remaining--;
return e;
}
@@ -759,8 +757,7 @@ public class ArrayDeque extends Abstr
throw new NoSuchElementException();
final Object[] es = elements;
E e = nonNullElementAt(es, cursor);
- lastRet = cursor;
- cursor = dec(cursor, es.length);
+ cursor = dec(lastRet = cursor, es.length);
remaining--;
return e;
}
@@ -822,6 +819,8 @@ public class ArrayDeque extends Abstr
/** Constructs spliterator over the given range. */
DeqSpliterator(int origin, int fence) {
+ // assert 0 <= origin && origin < elements.length;
+ // assert 0 <= fence && fence < elements.length;
this.cursor = origin;
this.fence = fence;
}
@@ -864,14 +863,15 @@ public class ArrayDeque extends Abstr
}
public boolean tryAdvance(Consumer super E> action) {
- if (action == null)
- throw new NullPointerException();
- final int t, i;
- if ((t = getFence()) == (i = cursor))
- return false;
+ Objects.requireNonNull(action);
final Object[] es = elements;
+ if (fence < 0) { fence = tail; cursor = head; } // late-binding
+ final int i;
+ if ((i = cursor) == fence)
+ return false;
+ E e = nonNullElementAt(es, i);
cursor = inc(i, es.length);
- action.accept(nonNullElementAt(es, i));
+ action.accept(e);
return true;
}
@@ -887,6 +887,9 @@ public class ArrayDeque extends Abstr
}
}
+ /**
+ * @throws NullPointerException {@inheritDoc}
+ */
public void forEach(Consumer super E> action) {
Objects.requireNonNull(action);
final Object[] es = elements;
@@ -1075,11 +1078,14 @@ public class ArrayDeque extends Abstr
/**
* Nulls out slots starting at array index i, upto index end.
+ * Condition i == end means "empty" - nothing to do.
*/
private static void circularClear(Object[] es, int i, int end) {
+ // assert 0 <= i && i < es.length;
+ // assert 0 <= end && end < es.length;
for (int to = (i <= end) ? end : es.length;
; i = 0, to = end) {
- Arrays.fill(es, i, to, null);
+ for (; i < to; i++) es[i] = null;
if (to == end) break;
}
}
@@ -1243,8 +1249,8 @@ public class ArrayDeque extends Abstr
// head == tail disambiguates to "empty".
try {
int capacity = elements.length;
- // assert head >= 0 && head < capacity;
- // assert tail >= 0 && tail < capacity;
+ // assert 0 <= head && head < capacity;
+ // assert 0 <= tail && tail < capacity;
// assert capacity > 0;
// assert size() < capacity;
// assert head == tail || elements[head] != null;