9 |
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import java.util.function.Consumer; |
10 |
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import java.util.function.Predicate; |
11 |
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import java.util.function.UnaryOperator; |
12 |
+ |
import jdk.internal.misc.SharedSecrets; |
13 |
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|
14 |
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/** |
15 |
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* Resizable-array implementation of the {@link Deque} interface. Array |
51 |
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* Iterator} interfaces. |
52 |
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* |
53 |
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* <p>This class is a member of the |
54 |
< |
* <a href="{@docRoot}/../technotes/guides/collections/index.html"> |
54 |
> |
* <a href="{@docRoot}/java.base/java/util/package-summary.html#CollectionsFramework"> |
55 |
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* Java Collections Framework</a>. |
56 |
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* |
57 |
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* @author Josh Bloch and Doug Lea |
61 |
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public class ArrayDeque<E> extends AbstractCollection<E> |
62 |
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implements Deque<E>, Cloneable, Serializable |
63 |
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{ |
64 |
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/* |
65 |
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* VMs excel at optimizing simple array loops where indices are |
66 |
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* incrementing or decrementing over a valid slice, e.g. |
67 |
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* |
68 |
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* for (int i = start; i < end; i++) ... elements[i] |
69 |
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* |
70 |
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* Because in a circular array, elements are in general stored in |
71 |
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* two disjoint such slices, we help the VM by writing unusual |
72 |
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* nested loops for all traversals over the elements. Having only |
73 |
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* one hot inner loop body instead of two or three eases human |
74 |
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* maintenance and encourages VM loop inlining into the caller. |
75 |
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*/ |
76 |
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|
77 |
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/** |
78 |
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* The array in which the elements of the deque are stored. |
79 |
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* We guarantee that all array cells not holding deque elements |
80 |
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* are always null. |
79 |
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* All array cells not holding deque elements are always null. |
80 |
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* The array always has at least one null slot (at tail). |
81 |
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*/ |
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transient Object[] elements; |
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|
84 |
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/** |
85 |
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* The index of the element at the head of the deque (which is the |
86 |
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* element that would be removed by remove() or pop()); or an |
87 |
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* arbitrary number 0 <= head < elements.length if the deque is empty. |
87 |
> |
* arbitrary number 0 <= head < elements.length equal to tail if |
88 |
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* the deque is empty. |
89 |
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*/ |
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transient int head; |
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|
92 |
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/** Number of elements in this collection. */ |
93 |
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transient int size; |
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> |
/** |
93 |
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* The index at which the next element would be added to the tail |
94 |
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* of the deque (via addLast(E), add(E), or push(E)); |
95 |
> |
* elements[tail] is always null. |
96 |
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*/ |
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transient int tail; |
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|
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/** |
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* The maximum size of array to allocate. |
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*/ |
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private void grow(int needed) { |
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// overflow-conscious code |
114 |
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// checkInvariants(); |
96 |
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int oldCapacity = elements.length; |
114 |
> |
final int oldCapacity = elements.length; |
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int newCapacity; |
116 |
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// Double size if small; else grow by 50% |
116 |
> |
// Double capacity if small; else grow by 50% |
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int jump = (oldCapacity < 64) ? (oldCapacity + 2) : (oldCapacity >> 1); |
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if (jump < needed |
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|| (newCapacity = (oldCapacity + jump)) - MAX_ARRAY_SIZE > 0) |
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newCapacity = newCapacity(needed, jump); |
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< |
elements = Arrays.copyOf(elements, newCapacity); |
122 |
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if (oldCapacity - head < size) { |
121 |
> |
final Object[] es = elements = Arrays.copyOf(elements, newCapacity); |
122 |
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// Exceptionally, here tail == head needs to be disambiguated |
123 |
> |
if (tail < head || (tail == head && es[head] != null)) { |
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// wrap around; slide first leg forward to end of array |
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int newSpace = newCapacity - oldCapacity; |
126 |
< |
System.arraycopy(elements, head, |
127 |
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elements, head + newSpace, |
126 |
> |
System.arraycopy(es, head, |
127 |
> |
es, head + newSpace, |
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oldCapacity - head); |
129 |
< |
Arrays.fill(elements, head, head + newSpace, null); |
130 |
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head += newSpace; |
129 |
> |
for (int i = head, to = (head += newSpace); i < to; i++) |
130 |
> |
es[i] = null; |
131 |
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} |
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// checkInvariants(); |
133 |
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} |
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|
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/** Capacity calculation for edge conditions, especially overflow. */ |
136 |
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private int newCapacity(int needed, int jump) { |
137 |
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int oldCapacity = elements.length; |
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int minCapacity; |
137 |
> |
final int oldCapacity = elements.length, minCapacity; |
138 |
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if ((minCapacity = oldCapacity + needed) - MAX_ARRAY_SIZE > 0) { |
139 |
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if (minCapacity < 0) |
140 |
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throw new IllegalStateException("Sorry, deque too big"); |
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* @since TBD |
156 |
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*/ |
157 |
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/* public */ void ensureCapacity(int minCapacity) { |
158 |
< |
if (minCapacity > elements.length) |
159 |
< |
grow(minCapacity - elements.length); |
158 |
> |
int needed; |
159 |
> |
if ((needed = (minCapacity + 1 - elements.length)) > 0) |
160 |
> |
grow(needed); |
161 |
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// checkInvariants(); |
162 |
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} |
163 |
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|
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* @since TBD |
168 |
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*/ |
169 |
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/* public */ void trimToSize() { |
170 |
< |
if (size < elements.length) { |
171 |
< |
elements = toArray(); |
170 |
> |
int size; |
171 |
> |
if ((size = size()) + 1 < elements.length) { |
172 |
> |
elements = toArray(new Object[size + 1]); |
173 |
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head = 0; |
174 |
+ |
tail = size; |
175 |
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} |
176 |
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// checkInvariants(); |
177 |
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} |
181 |
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* sufficient to hold 16 elements. |
182 |
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*/ |
183 |
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public ArrayDeque() { |
184 |
< |
elements = new Object[16]; |
184 |
> |
elements = new Object[16 + 1]; |
185 |
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} |
186 |
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|
187 |
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/** |
191 |
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* @param numElements lower bound on initial capacity of the deque |
192 |
|
*/ |
193 |
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public ArrayDeque(int numElements) { |
194 |
< |
elements = new Object[numElements]; |
194 |
> |
elements = |
195 |
> |
new Object[(numElements < 1) ? 1 : |
196 |
> |
(numElements == Integer.MAX_VALUE) ? Integer.MAX_VALUE : |
197 |
> |
numElements + 1]; |
198 |
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} |
199 |
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|
200 |
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/** |
208 |
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* @throws NullPointerException if the specified collection is null |
209 |
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*/ |
210 |
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public ArrayDeque(Collection<? extends E> c) { |
211 |
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Object[] elements = c.toArray(); |
212 |
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// defend against c.toArray (incorrectly) not returning Object[] |
189 |
< |
// (see e.g. https://bugs.openjdk.java.net/browse/JDK-6260652) |
190 |
< |
size = elements.length; |
191 |
< |
if (elements.getClass() != Object[].class) |
192 |
< |
elements = Arrays.copyOf(elements, size, Object[].class); |
193 |
< |
for (Object obj : elements) |
194 |
< |
Objects.requireNonNull(obj); |
195 |
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this.elements = elements; |
211 |
> |
this(c.size()); |
212 |
> |
copyElements(c); |
213 |
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} |
214 |
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|
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/** |
216 |
< |
* Increments i, mod modulus. |
216 |
> |
* Circularly increments i, mod modulus. |
217 |
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* Precondition and postcondition: 0 <= i < modulus. |
218 |
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*/ |
219 |
|
static final int inc(int i, int modulus) { |
220 |
< |
if (++i == modulus) i = 0; |
220 |
> |
if (++i >= modulus) i = 0; |
221 |
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return i; |
222 |
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} |
223 |
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|
224 |
|
/** |
225 |
< |
* Decrements i, mod modulus. |
225 |
> |
* Circularly decrements i, mod modulus. |
226 |
|
* Precondition and postcondition: 0 <= i < modulus. |
227 |
|
*/ |
228 |
|
static final int dec(int i, int modulus) { |
229 |
< |
if (--i < 0) i += modulus; |
229 |
> |
if (--i < 0) i = modulus - 1; |
230 |
|
return i; |
231 |
|
} |
232 |
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|
233 |
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/** |
234 |
< |
* Adds i and j, mod modulus. |
235 |
< |
* Precondition and postcondition: 0 <= i < modulus, 0 <= j <= modulus. |
234 |
> |
* Circularly adds the given distance to index i, mod modulus. |
235 |
> |
* Precondition: 0 <= i < modulus, 0 <= distance <= modulus. |
236 |
> |
* @return index 0 <= i < modulus |
237 |
|
*/ |
238 |
< |
static final int add(int i, int j, int modulus) { |
239 |
< |
if ((i += j) - modulus >= 0) i -= modulus; |
238 |
> |
static final int inc(int i, int distance, int modulus) { |
239 |
> |
if ((i += distance) - modulus >= 0) i -= modulus; |
240 |
|
return i; |
241 |
|
} |
242 |
|
|
243 |
|
/** |
244 |
< |
* Returns the array index of the last element. |
245 |
< |
* May return invalid index -1 if there are no elements. |
244 |
> |
* Subtracts j from i, mod modulus. |
245 |
> |
* Index i must be logically ahead of index j. |
246 |
> |
* Precondition: 0 <= i < modulus, 0 <= j < modulus. |
247 |
> |
* @return the "circular distance" from j to i; corner case i == j |
248 |
> |
* is disambiguated to "empty", returning 0. |
249 |
|
*/ |
250 |
< |
final int tail() { |
251 |
< |
return add(head, size - 1, elements.length); |
250 |
> |
static final int sub(int i, int j, int modulus) { |
251 |
> |
if ((i -= j) < 0) i += modulus; |
252 |
> |
return i; |
253 |
|
} |
254 |
|
|
255 |
|
/** |
256 |
|
* Returns element at array index i. |
257 |
+ |
* This is a slight abuse of generics, accepted by javac. |
258 |
|
*/ |
259 |
|
@SuppressWarnings("unchecked") |
260 |
< |
final E elementAt(int i) { |
261 |
< |
return (E) elements[i]; |
260 |
> |
static final <E> E elementAt(Object[] es, int i) { |
261 |
> |
return (E) es[i]; |
262 |
|
} |
263 |
|
|
264 |
|
/** |
266 |
|
* This check doesn't catch all possible comodifications, |
267 |
|
* but does catch ones that corrupt traversal. |
268 |
|
*/ |
269 |
< |
E checkedElementAt(Object[] elements, int i) { |
270 |
< |
@SuppressWarnings("unchecked") E e = (E) elements[i]; |
269 |
> |
static final <E> E nonNullElementAt(Object[] es, int i) { |
270 |
> |
@SuppressWarnings("unchecked") E e = (E) es[i]; |
271 |
|
if (e == null) |
272 |
|
throw new ConcurrentModificationException(); |
273 |
|
return e; |
284 |
|
* @throws NullPointerException if the specified element is null |
285 |
|
*/ |
286 |
|
public void addFirst(E e) { |
287 |
< |
// checkInvariants(); |
288 |
< |
Objects.requireNonNull(e); |
289 |
< |
final Object[] elements; |
290 |
< |
final int capacity, s; |
291 |
< |
if ((s = size) == (capacity = (elements = this.elements).length)) |
292 |
< |
addFirstSlowPath(e); |
270 |
< |
else |
271 |
< |
elements[head = dec(head, capacity)] = e; |
272 |
< |
size = s + 1; |
287 |
> |
if (e == null) |
288 |
> |
throw new NullPointerException(); |
289 |
> |
final Object[] es = elements; |
290 |
> |
es[head = dec(head, es.length)] = e; |
291 |
> |
if (head == tail) |
292 |
> |
grow(1); |
293 |
|
// checkInvariants(); |
294 |
|
} |
295 |
|
|
276 |
– |
private void addFirstSlowPath(E e) { |
277 |
– |
grow(1); |
278 |
– |
final Object[] elements = this.elements; |
279 |
– |
elements[head = dec(head, elements.length)] = e; |
280 |
– |
} |
281 |
– |
|
296 |
|
/** |
297 |
|
* Inserts the specified element at the end of this deque. |
298 |
|
* |
302 |
|
* @throws NullPointerException if the specified element is null |
303 |
|
*/ |
304 |
|
public void addLast(E e) { |
305 |
+ |
if (e == null) |
306 |
+ |
throw new NullPointerException(); |
307 |
+ |
final Object[] es = elements; |
308 |
+ |
es[tail] = e; |
309 |
+ |
if (head == (tail = inc(tail, es.length))) |
310 |
+ |
grow(1); |
311 |
|
// checkInvariants(); |
292 |
– |
Objects.requireNonNull(e); |
293 |
– |
final Object[] elements; |
294 |
– |
final int capacity, s; |
295 |
– |
if ((s = size) == (capacity = (elements = this.elements).length)) |
296 |
– |
addLastSlowPath(e); |
297 |
– |
else |
298 |
– |
elements[add(head, s, capacity)] = e; |
299 |
– |
size = s + 1; |
300 |
– |
// checkInvariants(); |
301 |
– |
} |
302 |
– |
|
303 |
– |
private void addLastSlowPath(E e) { |
304 |
– |
grow(1); |
305 |
– |
final Object[] elements = this.elements; |
306 |
– |
elements[add(head, size, elements.length)] = e; |
312 |
|
} |
313 |
|
|
314 |
|
/** |
315 |
|
* Adds all of the elements in the specified collection at the end |
316 |
|
* of this deque, as if by calling {@link #addLast} on each one, |
317 |
< |
* in the order that they are returned by the collection's |
313 |
< |
* iterator. |
317 |
> |
* in the order that they are returned by the collection's iterator. |
318 |
|
* |
319 |
|
* @param c the elements to be inserted into this deque |
320 |
|
* @return {@code true} if this deque changed as a result of the call |
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, needed; |
326 |
> |
if ((needed = (s = size()) + c.size() + 1 - elements.length) > 0) |
327 |
|
grow(needed); |
328 |
< |
c.forEach((e) -> addLast(e)); |
328 |
> |
copyElements(c); |
329 |
|
// checkInvariants(); |
330 |
< |
return size > s; |
330 |
> |
return size() > s; |
331 |
> |
} |
332 |
> |
|
333 |
> |
private void copyElements(Collection<? extends E> c) { |
334 |
> |
c.forEach(this::addLast); |
335 |
|
} |
336 |
|
|
337 |
|
/** |
362 |
|
* @throws NoSuchElementException {@inheritDoc} |
363 |
|
*/ |
364 |
|
public E removeFirst() { |
357 |
– |
// checkInvariants(); |
365 |
|
E e = pollFirst(); |
366 |
|
if (e == null) |
367 |
|
throw new NoSuchElementException(); |
368 |
+ |
// checkInvariants(); |
369 |
|
return e; |
370 |
|
} |
371 |
|
|
373 |
|
* @throws NoSuchElementException {@inheritDoc} |
374 |
|
*/ |
375 |
|
public E removeLast() { |
368 |
– |
// checkInvariants(); |
376 |
|
E e = pollLast(); |
377 |
|
if (e == null) |
378 |
|
throw new NoSuchElementException(); |
379 |
+ |
// checkInvariants(); |
380 |
|
return e; |
381 |
|
} |
382 |
|
|
383 |
|
public E pollFirst() { |
384 |
+ |
final Object[] es; |
385 |
+ |
final int h; |
386 |
+ |
E e = elementAt(es = elements, h = head); |
387 |
+ |
if (e != null) { |
388 |
+ |
es[h] = null; |
389 |
+ |
head = inc(h, es.length); |
390 |
+ |
} |
391 |
|
// checkInvariants(); |
377 |
– |
final int s, h; |
378 |
– |
if ((s = size) == 0) |
379 |
– |
return null; |
380 |
– |
final Object[] elements = this.elements; |
381 |
– |
@SuppressWarnings("unchecked") E e = (E) elements[h = head]; |
382 |
– |
elements[h] = null; |
383 |
– |
head = inc(h, elements.length); |
384 |
– |
size = s - 1; |
392 |
|
return e; |
393 |
|
} |
394 |
|
|
395 |
|
public E pollLast() { |
396 |
+ |
final Object[] es; |
397 |
+ |
final int t; |
398 |
+ |
E e = elementAt(es = elements, t = dec(tail, es.length)); |
399 |
+ |
if (e != null) |
400 |
+ |
es[tail = t] = null; |
401 |
|
// checkInvariants(); |
390 |
– |
final int s, tail; |
391 |
– |
if ((s = size) == 0) |
392 |
– |
return null; |
393 |
– |
final Object[] elements = this.elements; |
394 |
– |
@SuppressWarnings("unchecked") |
395 |
– |
E e = (E) elements[tail = add(head, s - 1, elements.length)]; |
396 |
– |
elements[tail] = null; |
397 |
– |
size = s - 1; |
402 |
|
return e; |
403 |
|
} |
404 |
|
|
406 |
|
* @throws NoSuchElementException {@inheritDoc} |
407 |
|
*/ |
408 |
|
public E getFirst() { |
409 |
+ |
E e = elementAt(elements, head); |
410 |
+ |
if (e == null) |
411 |
+ |
throw new NoSuchElementException(); |
412 |
|
// checkInvariants(); |
413 |
< |
if (size == 0) throw new NoSuchElementException(); |
407 |
< |
return elementAt(head); |
413 |
> |
return e; |
414 |
|
} |
415 |
|
|
416 |
|
/** |
417 |
|
* @throws NoSuchElementException {@inheritDoc} |
418 |
|
*/ |
419 |
|
public E getLast() { |
420 |
+ |
final Object[] es = elements; |
421 |
+ |
E e = elementAt(es, dec(tail, es.length)); |
422 |
+ |
if (e == null) |
423 |
+ |
throw new NoSuchElementException(); |
424 |
|
// checkInvariants(); |
425 |
< |
if (size == 0) throw new NoSuchElementException(); |
416 |
< |
return elementAt(tail()); |
425 |
> |
return e; |
426 |
|
} |
427 |
|
|
428 |
|
public E peekFirst() { |
429 |
|
// checkInvariants(); |
430 |
< |
return (size == 0) ? null : elementAt(head); |
430 |
> |
return elementAt(elements, head); |
431 |
|
} |
432 |
|
|
433 |
|
public E peekLast() { |
434 |
|
// checkInvariants(); |
435 |
< |
return (size == 0) ? null : elementAt(tail()); |
435 |
> |
final Object[] es; |
436 |
> |
return elementAt(es = elements, dec(tail, es.length)); |
437 |
|
} |
438 |
|
|
439 |
|
/** |
449 |
|
* @return {@code true} if the deque contained the specified element |
450 |
|
*/ |
451 |
|
public boolean removeFirstOccurrence(Object o) { |
442 |
– |
// checkInvariants(); |
452 |
|
if (o != null) { |
453 |
< |
final Object[] elements = this.elements; |
454 |
< |
final int capacity = elements.length; |
455 |
< |
for (int k = size, i = head; --k >= 0; i = inc(i, capacity)) { |
456 |
< |
if (o.equals(elements[i])) { |
457 |
< |
delete(i); |
458 |
< |
return true; |
459 |
< |
} |
453 |
> |
final Object[] es = elements; |
454 |
> |
for (int i = head, end = tail, to = (i <= end) ? end : es.length; |
455 |
> |
; i = 0, to = end) { |
456 |
> |
for (; i < to; i++) |
457 |
> |
if (o.equals(es[i])) { |
458 |
> |
delete(i); |
459 |
> |
return true; |
460 |
> |
} |
461 |
> |
if (to == end) break; |
462 |
|
} |
463 |
|
} |
464 |
|
return false; |
478 |
|
*/ |
479 |
|
public boolean removeLastOccurrence(Object o) { |
480 |
|
if (o != null) { |
481 |
< |
final Object[] elements = this.elements; |
482 |
< |
final int capacity = elements.length; |
483 |
< |
for (int k = size, i = add(head, k - 1, capacity); |
484 |
< |
--k >= 0; i = dec(i, capacity)) { |
485 |
< |
if (o.equals(elements[i])) { |
486 |
< |
delete(i); |
487 |
< |
return true; |
488 |
< |
} |
481 |
> |
final Object[] es = elements; |
482 |
> |
for (int i = tail, end = head, to = (i >= end) ? end : 0; |
483 |
> |
; i = es.length, to = end) { |
484 |
> |
for (i--; i > to - 1; i--) |
485 |
> |
if (o.equals(es[i])) { |
486 |
> |
delete(i); |
487 |
> |
return true; |
488 |
> |
} |
489 |
> |
if (to == end) break; |
490 |
|
} |
491 |
|
} |
492 |
|
return false; |
524 |
|
/** |
525 |
|
* Retrieves and removes the head of the queue represented by this deque. |
526 |
|
* |
527 |
< |
* This method differs from {@link #poll poll} only in that it throws an |
528 |
< |
* exception if this deque is empty. |
527 |
> |
* This method differs from {@link #poll() poll()} only in that it |
528 |
> |
* throws an exception if this deque is empty. |
529 |
|
* |
530 |
|
* <p>This method is equivalent to {@link #removeFirst}. |
531 |
|
* |
614 |
|
* <p>This method is called delete rather than remove to emphasize |
615 |
|
* that its semantics differ from those of {@link List#remove(int)}. |
616 |
|
* |
617 |
< |
* @return true if elements moved backwards |
617 |
> |
* @return true if elements near tail moved backwards |
618 |
|
*/ |
619 |
|
boolean delete(int i) { |
620 |
|
// checkInvariants(); |
621 |
< |
final Object[] elements = this.elements; |
622 |
< |
final int capacity = elements.length; |
623 |
< |
final int h = head; |
624 |
< |
int front; // number of elements before to-be-deleted elt |
625 |
< |
if ((front = i - h) < 0) front += capacity; |
626 |
< |
final int back = size - front - 1; // number of elements after |
621 |
> |
final Object[] es = elements; |
622 |
> |
final int capacity = es.length; |
623 |
> |
final int h, t; |
624 |
> |
// number of elements before to-be-deleted elt |
625 |
> |
final int front = sub(i, h = head, capacity); |
626 |
> |
// number of elements after to-be-deleted elt |
627 |
> |
final int back = sub(t = tail, i, capacity) - 1; |
628 |
|
if (front < back) { |
629 |
|
// move front elements forwards |
630 |
|
if (h <= i) { |
631 |
< |
System.arraycopy(elements, h, elements, h + 1, front); |
631 |
> |
System.arraycopy(es, h, es, h + 1, front); |
632 |
|
} else { // Wrap around |
633 |
< |
System.arraycopy(elements, 0, elements, 1, i); |
634 |
< |
elements[0] = elements[capacity - 1]; |
635 |
< |
System.arraycopy(elements, h, elements, h + 1, front - (i + 1)); |
633 |
> |
System.arraycopy(es, 0, es, 1, i); |
634 |
> |
es[0] = es[capacity - 1]; |
635 |
> |
System.arraycopy(es, h, es, h + 1, front - (i + 1)); |
636 |
|
} |
637 |
< |
elements[h] = null; |
637 |
> |
es[h] = null; |
638 |
|
head = inc(h, capacity); |
626 |
– |
size--; |
639 |
|
// checkInvariants(); |
640 |
|
return false; |
641 |
|
} else { |
642 |
|
// move back elements backwards |
643 |
< |
int tail = tail(); |
643 |
> |
tail = dec(t, capacity); |
644 |
|
if (i <= tail) { |
645 |
< |
System.arraycopy(elements, i + 1, elements, i, back); |
645 |
> |
System.arraycopy(es, i + 1, es, i, back); |
646 |
|
} else { // Wrap around |
647 |
< |
int firstLeg = capacity - (i + 1); |
648 |
< |
System.arraycopy(elements, i + 1, elements, i, firstLeg); |
649 |
< |
elements[capacity - 1] = elements[0]; |
638 |
< |
System.arraycopy(elements, 1, elements, 0, back - firstLeg - 1); |
647 |
> |
System.arraycopy(es, i + 1, es, i, capacity - (i + 1)); |
648 |
> |
es[capacity - 1] = es[0]; |
649 |
> |
System.arraycopy(es, 1, es, 0, t - 1); |
650 |
|
} |
651 |
< |
elements[tail] = null; |
641 |
< |
size--; |
651 |
> |
es[tail] = null; |
652 |
|
// checkInvariants(); |
653 |
|
return true; |
654 |
|
} |
662 |
|
* @return the number of elements in this deque |
663 |
|
*/ |
664 |
|
public int size() { |
665 |
< |
return size; |
665 |
> |
return sub(tail, head, elements.length); |
666 |
|
} |
667 |
|
|
668 |
|
/** |
671 |
|
* @return {@code true} if this deque contains no elements |
672 |
|
*/ |
673 |
|
public boolean isEmpty() { |
674 |
< |
return size == 0; |
674 |
> |
return head == tail; |
675 |
|
} |
676 |
|
|
677 |
|
/** |
695 |
|
int cursor; |
696 |
|
|
697 |
|
/** Number of elements yet to be returned. */ |
698 |
< |
int remaining = size; |
698 |
> |
int remaining = size(); |
699 |
|
|
700 |
|
/** |
701 |
|
* Index of element returned by most recent call to next. |
710 |
|
} |
711 |
|
|
712 |
|
public E next() { |
713 |
< |
if (remaining == 0) |
713 |
> |
if (remaining <= 0) |
714 |
|
throw new NoSuchElementException(); |
715 |
< |
E e = checkedElementAt(elements, cursor); |
716 |
< |
lastRet = cursor; |
717 |
< |
cursor = inc(cursor, elements.length); |
715 |
> |
final Object[] es = elements; |
716 |
> |
E e = nonNullElementAt(es, cursor); |
717 |
> |
cursor = inc(lastRet = cursor, es.length); |
718 |
|
remaining--; |
719 |
|
return e; |
720 |
|
} |
721 |
|
|
722 |
|
void postDelete(boolean leftShifted) { |
723 |
|
if (leftShifted) |
724 |
< |
cursor = dec(cursor, elements.length); // undo inc in next |
724 |
> |
cursor = dec(cursor, elements.length); |
725 |
|
} |
726 |
|
|
727 |
|
public final void remove() { |
733 |
|
|
734 |
|
public void forEachRemaining(Consumer<? super E> action) { |
735 |
|
Objects.requireNonNull(action); |
736 |
< |
final Object[] elements = ArrayDeque.this.elements; |
737 |
< |
final int capacity = elements.length; |
738 |
< |
int k = remaining; |
736 |
> |
int r; |
737 |
> |
if ((r = remaining) <= 0) |
738 |
> |
return; |
739 |
|
remaining = 0; |
740 |
< |
for (int i = cursor; --k >= 0; i = inc(i, capacity)) |
741 |
< |
action.accept(checkedElementAt(elements, i)); |
740 |
> |
final Object[] es = elements; |
741 |
> |
if (es[cursor] == null || sub(tail, cursor, es.length) != r) |
742 |
> |
throw new ConcurrentModificationException(); |
743 |
> |
for (int i = cursor, end = tail, to = (i <= end) ? end : es.length; |
744 |
> |
; i = 0, to = end) { |
745 |
> |
for (; i < to; i++) |
746 |
> |
action.accept(elementAt(es, i)); |
747 |
> |
if (to == end) { |
748 |
> |
if (end != tail) |
749 |
> |
throw new ConcurrentModificationException(); |
750 |
> |
lastRet = dec(end, es.length); |
751 |
> |
break; |
752 |
> |
} |
753 |
> |
} |
754 |
|
} |
755 |
|
} |
756 |
|
|
757 |
|
private class DescendingIterator extends DeqIterator { |
758 |
< |
DescendingIterator() { cursor = tail(); } |
758 |
> |
DescendingIterator() { cursor = dec(tail, elements.length); } |
759 |
|
|
760 |
|
public final E next() { |
761 |
< |
if (remaining == 0) |
761 |
> |
if (remaining <= 0) |
762 |
|
throw new NoSuchElementException(); |
763 |
< |
E e = checkedElementAt(elements, cursor); |
764 |
< |
lastRet = cursor; |
765 |
< |
cursor = dec(cursor, elements.length); |
763 |
> |
final Object[] es = elements; |
764 |
> |
E e = nonNullElementAt(es, cursor); |
765 |
> |
cursor = dec(lastRet = cursor, es.length); |
766 |
|
remaining--; |
767 |
|
return e; |
768 |
|
} |
769 |
|
|
770 |
|
void postDelete(boolean leftShifted) { |
771 |
|
if (!leftShifted) |
772 |
< |
cursor = inc(cursor, elements.length); // undo dec in next |
772 |
> |
cursor = inc(cursor, elements.length); |
773 |
|
} |
774 |
|
|
775 |
|
public final void forEachRemaining(Consumer<? super E> action) { |
776 |
|
Objects.requireNonNull(action); |
777 |
< |
final Object[] elements = ArrayDeque.this.elements; |
778 |
< |
final int capacity = elements.length; |
779 |
< |
int k = remaining; |
777 |
> |
int r; |
778 |
> |
if ((r = remaining) <= 0) |
779 |
> |
return; |
780 |
|
remaining = 0; |
781 |
< |
for (int i = cursor; --k >= 0; i = dec(i, capacity)) |
782 |
< |
action.accept(checkedElementAt(elements, i)); |
781 |
> |
final Object[] es = elements; |
782 |
> |
if (es[cursor] == null || sub(cursor, head, es.length) + 1 != r) |
783 |
> |
throw new ConcurrentModificationException(); |
784 |
> |
for (int i = cursor, end = head, to = (i >= end) ? end : 0; |
785 |
> |
; i = es.length - 1, to = end) { |
786 |
> |
// hotspot generates faster code than for: i >= to ! |
787 |
> |
for (; i > to - 1; i--) |
788 |
> |
action.accept(elementAt(es, i)); |
789 |
> |
if (to == end) { |
790 |
> |
if (end != head) |
791 |
> |
throw new ConcurrentModificationException(); |
792 |
> |
lastRet = end; |
793 |
> |
break; |
794 |
> |
} |
795 |
> |
} |
796 |
|
} |
797 |
|
} |
798 |
|
|
810 |
|
* @since 1.8 |
811 |
|
*/ |
812 |
|
public Spliterator<E> spliterator() { |
813 |
< |
return new ArrayDequeSpliterator(); |
813 |
> |
return new DeqSpliterator(); |
814 |
|
} |
815 |
|
|
816 |
< |
final class ArrayDequeSpliterator implements Spliterator<E> { |
817 |
< |
private int cursor; |
818 |
< |
private int remaining; // -1 until late-binding first use |
816 |
> |
final class DeqSpliterator implements Spliterator<E> { |
817 |
> |
private int fence; // -1 until first use |
818 |
> |
private int cursor; // current index, modified on traverse/split |
819 |
|
|
820 |
|
/** Constructs late-binding spliterator over all elements. */ |
821 |
< |
ArrayDequeSpliterator() { |
822 |
< |
this.remaining = -1; |
788 |
< |
} |
789 |
< |
|
790 |
< |
/** Constructs spliterator over the given slice. */ |
791 |
< |
ArrayDequeSpliterator(int cursor, int count) { |
792 |
< |
this.cursor = cursor; |
793 |
< |
this.remaining = count; |
821 |
> |
DeqSpliterator() { |
822 |
> |
this.fence = -1; |
823 |
|
} |
824 |
|
|
825 |
< |
/** Ensures late-binding initialization; then returns remaining. */ |
826 |
< |
private int remaining() { |
827 |
< |
if (remaining < 0) { |
825 |
> |
/** Constructs spliterator over the given range. */ |
826 |
> |
DeqSpliterator(int origin, int fence) { |
827 |
> |
// assert 0 <= origin && origin < elements.length; |
828 |
> |
// assert 0 <= fence && fence < elements.length; |
829 |
> |
this.cursor = origin; |
830 |
> |
this.fence = fence; |
831 |
> |
} |
832 |
> |
|
833 |
> |
/** Ensures late-binding initialization; then returns fence. */ |
834 |
> |
private int getFence() { // force initialization |
835 |
> |
int t; |
836 |
> |
if ((t = fence) < 0) { |
837 |
> |
t = fence = tail; |
838 |
|
cursor = head; |
800 |
– |
remaining = size; |
839 |
|
} |
840 |
< |
return remaining; |
840 |
> |
return t; |
841 |
|
} |
842 |
|
|
843 |
< |
public ArrayDequeSpliterator trySplit() { |
844 |
< |
final int mid; |
845 |
< |
if ((mid = remaining() >> 1) > 0) { |
846 |
< |
int oldCursor = cursor; |
847 |
< |
cursor = add(cursor, mid, elements.length); |
848 |
< |
remaining -= mid; |
811 |
< |
return new ArrayDequeSpliterator(oldCursor, mid); |
812 |
< |
} |
813 |
< |
return null; |
843 |
> |
public DeqSpliterator trySplit() { |
844 |
> |
final Object[] es = elements; |
845 |
> |
final int i, n; |
846 |
> |
return ((n = sub(getFence(), i = cursor, es.length) >> 1) <= 0) |
847 |
> |
? null |
848 |
> |
: new DeqSpliterator(i, cursor = inc(i, n, es.length)); |
849 |
|
} |
850 |
|
|
851 |
|
public void forEachRemaining(Consumer<? super E> action) { |
852 |
< |
Objects.requireNonNull(action); |
853 |
< |
final Object[] elements = ArrayDeque.this.elements; |
854 |
< |
final int capacity = elements.length; |
855 |
< |
int k = remaining(); |
856 |
< |
remaining = 0; |
857 |
< |
for (int i = cursor; --k >= 0; i = inc(i, capacity)) |
858 |
< |
action.accept(checkedElementAt(elements, i)); |
852 |
> |
if (action == null) |
853 |
> |
throw new NullPointerException(); |
854 |
> |
final int end = getFence(), cursor = this.cursor; |
855 |
> |
final Object[] es = elements; |
856 |
> |
if (cursor != end) { |
857 |
> |
this.cursor = end; |
858 |
> |
// null check at both ends of range is sufficient |
859 |
> |
if (es[cursor] == null || es[dec(end, es.length)] == null) |
860 |
> |
throw new ConcurrentModificationException(); |
861 |
> |
for (int i = cursor, to = (i <= end) ? end : es.length; |
862 |
> |
; i = 0, to = end) { |
863 |
> |
for (; i < to; i++) |
864 |
> |
action.accept(elementAt(es, i)); |
865 |
> |
if (to == end) break; |
866 |
> |
} |
867 |
> |
} |
868 |
|
} |
869 |
|
|
870 |
|
public boolean tryAdvance(Consumer<? super E> action) { |
871 |
|
Objects.requireNonNull(action); |
872 |
< |
if (remaining() == 0) |
872 |
> |
final Object[] es = elements; |
873 |
> |
if (fence < 0) { fence = tail; cursor = head; } // late-binding |
874 |
> |
final int i; |
875 |
> |
if ((i = cursor) == fence) |
876 |
|
return false; |
877 |
< |
action.accept(checkedElementAt(elements, cursor)); |
878 |
< |
cursor = inc(cursor, elements.length); |
879 |
< |
remaining--; |
877 |
> |
E e = nonNullElementAt(es, i); |
878 |
> |
cursor = inc(i, es.length); |
879 |
> |
action.accept(e); |
880 |
|
return true; |
881 |
|
} |
882 |
|
|
883 |
|
public long estimateSize() { |
884 |
< |
return remaining(); |
884 |
> |
return sub(getFence(), cursor, elements.length); |
885 |
|
} |
886 |
|
|
887 |
|
public int characteristics() { |
892 |
|
} |
893 |
|
} |
894 |
|
|
895 |
+ |
/** |
896 |
+ |
* @throws NullPointerException {@inheritDoc} |
897 |
+ |
*/ |
898 |
|
public void forEach(Consumer<? super E> action) { |
849 |
– |
// checkInvariants(); |
899 |
|
Objects.requireNonNull(action); |
900 |
< |
final Object[] elements = this.elements; |
901 |
< |
final int capacity = elements.length; |
902 |
< |
for (int k = size, i = head; --k >= 0; i = inc(i, capacity)) |
903 |
< |
action.accept(elementAt(i)); |
900 |
> |
final Object[] es = elements; |
901 |
> |
for (int i = head, end = tail, to = (i <= end) ? end : es.length; |
902 |
> |
; i = 0, to = end) { |
903 |
> |
for (; i < to; i++) |
904 |
> |
action.accept(elementAt(es, i)); |
905 |
> |
if (to == end) { |
906 |
> |
if (end != tail) throw new ConcurrentModificationException(); |
907 |
> |
break; |
908 |
> |
} |
909 |
> |
} |
910 |
|
// checkInvariants(); |
911 |
|
} |
912 |
|
|
919 |
|
*/ |
920 |
|
/* public */ void replaceAll(UnaryOperator<E> operator) { |
921 |
|
Objects.requireNonNull(operator); |
922 |
< |
final Object[] elements = this.elements; |
923 |
< |
final int capacity = elements.length; |
924 |
< |
for (int k = size, i = head; --k >= 0; i = inc(i, capacity)) |
925 |
< |
elements[i] = operator.apply(elementAt(i)); |
922 |
> |
final Object[] es = elements; |
923 |
> |
for (int i = head, end = tail, to = (i <= end) ? end : es.length; |
924 |
> |
; i = 0, to = end) { |
925 |
> |
for (; i < to; i++) |
926 |
> |
es[i] = operator.apply(elementAt(es, i)); |
927 |
> |
if (to == end) { |
928 |
> |
if (end != tail) throw new ConcurrentModificationException(); |
929 |
> |
break; |
930 |
> |
} |
931 |
> |
} |
932 |
|
// checkInvariants(); |
933 |
|
} |
934 |
|
|
959 |
|
/** Implementation of bulk remove methods. */ |
960 |
|
private boolean bulkRemove(Predicate<? super E> filter) { |
961 |
|
// checkInvariants(); |
962 |
< |
final Object[] elements = this.elements; |
963 |
< |
final int capacity = elements.length; |
964 |
< |
int i = head, j = i, remaining = size, deleted = 0; |
965 |
< |
try { |
966 |
< |
for (; remaining > 0; remaining--, i = inc(i, capacity)) { |
967 |
< |
@SuppressWarnings("unchecked") E e = (E) elements[i]; |
968 |
< |
if (filter.test(e)) |
969 |
< |
deleted++; |
970 |
< |
else { |
971 |
< |
if (j != i) |
911 |
< |
elements[j] = e; |
912 |
< |
j = inc(j, capacity); |
913 |
< |
} |
962 |
> |
final Object[] es = elements; |
963 |
> |
// Optimize for initial run of survivors |
964 |
> |
for (int i = head, end = tail, to = (i <= end) ? end : es.length; |
965 |
> |
; i = 0, to = end) { |
966 |
> |
for (; i < to; i++) |
967 |
> |
if (filter.test(elementAt(es, i))) |
968 |
> |
return bulkRemoveModified(filter, i); |
969 |
> |
if (to == end) { |
970 |
> |
if (end != tail) throw new ConcurrentModificationException(); |
971 |
> |
break; |
972 |
|
} |
915 |
– |
return deleted > 0; |
916 |
– |
} catch (Throwable ex) { |
917 |
– |
if (deleted > 0) |
918 |
– |
for (; remaining > 0; |
919 |
– |
remaining--, i = inc(i, capacity), j = inc(j, capacity)) |
920 |
– |
elements[j] = elements[i]; |
921 |
– |
throw ex; |
922 |
– |
} finally { |
923 |
– |
size -= deleted; |
924 |
– |
for (; --deleted >= 0; j = inc(j, capacity)) |
925 |
– |
elements[j] = null; |
926 |
– |
// checkInvariants(); |
973 |
|
} |
974 |
+ |
return false; |
975 |
+ |
} |
976 |
+ |
|
977 |
+ |
// A tiny bit set implementation |
978 |
+ |
|
979 |
+ |
private static long[] nBits(int n) { |
980 |
+ |
return new long[((n - 1) >> 6) + 1]; |
981 |
+ |
} |
982 |
+ |
private static void setBit(long[] bits, int i) { |
983 |
+ |
bits[i >> 6] |= 1L << i; |
984 |
+ |
} |
985 |
+ |
private static boolean isClear(long[] bits, int i) { |
986 |
+ |
return (bits[i >> 6] & (1L << i)) == 0; |
987 |
+ |
} |
988 |
+ |
|
989 |
+ |
/** |
990 |
+ |
* Helper for bulkRemove, in case of at least one deletion. |
991 |
+ |
* Tolerate predicates that reentrantly access the collection for |
992 |
+ |
* read (but writers still get CME), so traverse once to find |
993 |
+ |
* elements to delete, a second pass to physically expunge. |
994 |
+ |
* |
995 |
+ |
* @param beg valid index of first element to be deleted |
996 |
+ |
*/ |
997 |
+ |
private boolean bulkRemoveModified( |
998 |
+ |
Predicate<? super E> filter, final int beg) { |
999 |
+ |
final Object[] es = elements; |
1000 |
+ |
final int capacity = es.length; |
1001 |
+ |
final int end = tail; |
1002 |
+ |
final long[] deathRow = nBits(sub(end, beg, capacity)); |
1003 |
+ |
deathRow[0] = 1L; // set bit 0 |
1004 |
+ |
for (int i = beg + 1, to = (i <= end) ? end : es.length, k = beg; |
1005 |
+ |
; i = 0, to = end, k -= capacity) { |
1006 |
+ |
for (; i < to; i++) |
1007 |
+ |
if (filter.test(elementAt(es, i))) |
1008 |
+ |
setBit(deathRow, i - k); |
1009 |
+ |
if (to == end) break; |
1010 |
+ |
} |
1011 |
+ |
// a two-finger traversal, with hare i reading, tortoise w writing |
1012 |
+ |
int w = beg; |
1013 |
+ |
for (int i = beg + 1, to = (i <= end) ? end : es.length, k = beg; |
1014 |
+ |
; w = 0) { // w rejoins i on second leg |
1015 |
+ |
// In this loop, i and w are on the same leg, with i > w |
1016 |
+ |
for (; i < to; i++) |
1017 |
+ |
if (isClear(deathRow, i - k)) |
1018 |
+ |
es[w++] = es[i]; |
1019 |
+ |
if (to == end) break; |
1020 |
+ |
// In this loop, w is on the first leg, i on the second |
1021 |
+ |
for (i = 0, to = end, k -= capacity; i < to && w < capacity; i++) |
1022 |
+ |
if (isClear(deathRow, i - k)) |
1023 |
+ |
es[w++] = es[i]; |
1024 |
+ |
if (i >= to) { |
1025 |
+ |
if (w == capacity) w = 0; // "corner" case |
1026 |
+ |
break; |
1027 |
+ |
} |
1028 |
+ |
} |
1029 |
+ |
if (end != tail) throw new ConcurrentModificationException(); |
1030 |
+ |
circularClear(es, tail = w, end); |
1031 |
+ |
// checkInvariants(); |
1032 |
+ |
return true; |
1033 |
|
} |
1034 |
|
|
1035 |
|
/** |
1042 |
|
*/ |
1043 |
|
public boolean contains(Object o) { |
1044 |
|
if (o != null) { |
1045 |
< |
final Object[] elements = this.elements; |
1046 |
< |
final int capacity = elements.length; |
1047 |
< |
for (int k = size, i = head; --k >= 0; i = inc(i, capacity)) |
1048 |
< |
if (o.equals(elements[i])) |
1049 |
< |
return true; |
1045 |
> |
final Object[] es = elements; |
1046 |
> |
for (int i = head, end = tail, to = (i <= end) ? end : es.length; |
1047 |
> |
; i = 0, to = end) { |
1048 |
> |
for (; i < to; i++) |
1049 |
> |
if (o.equals(es[i])) |
1050 |
> |
return true; |
1051 |
> |
if (to == end) break; |
1052 |
> |
} |
1053 |
|
} |
1054 |
|
return false; |
1055 |
|
} |
1076 |
|
* The deque will be empty after this call returns. |
1077 |
|
*/ |
1078 |
|
public void clear() { |
1079 |
< |
final Object[] elements = this.elements; |
1080 |
< |
final int capacity = elements.length, tail = head + size; |
973 |
< |
if (capacity - tail >= 0) |
974 |
< |
Arrays.fill(elements, head, tail, null); |
975 |
< |
else { |
976 |
< |
Arrays.fill(elements, head, capacity, null); |
977 |
< |
Arrays.fill(elements, 0, tail - capacity, null); |
978 |
< |
} |
979 |
< |
size = head = 0; |
1079 |
> |
circularClear(elements, head, tail); |
1080 |
> |
head = tail = 0; |
1081 |
|
// checkInvariants(); |
1082 |
|
} |
1083 |
|
|
1084 |
|
/** |
1085 |
+ |
* Nulls out slots starting at array index i, upto index end. |
1086 |
+ |
* Condition i == end means "empty" - nothing to do. |
1087 |
+ |
*/ |
1088 |
+ |
private static void circularClear(Object[] es, int i, int end) { |
1089 |
+ |
// assert 0 <= i && i < es.length; |
1090 |
+ |
// assert 0 <= end && end < es.length; |
1091 |
+ |
for (int to = (i <= end) ? end : es.length; |
1092 |
+ |
; i = 0, to = end) { |
1093 |
+ |
for (; i < to; i++) es[i] = null; |
1094 |
+ |
if (to == end) break; |
1095 |
+ |
} |
1096 |
+ |
} |
1097 |
+ |
|
1098 |
+ |
/** |
1099 |
|
* Returns an array containing all of the elements in this deque |
1100 |
|
* in proper sequence (from first to last element). |
1101 |
|
* |
1113 |
|
} |
1114 |
|
|
1115 |
|
private <T> T[] toArray(Class<T[]> klazz) { |
1116 |
< |
final Object[] elements = this.elements; |
1002 |
< |
final int capacity = elements.length; |
1003 |
< |
final int head = this.head, tail = head + size; |
1116 |
> |
final Object[] es = elements; |
1117 |
|
final T[] a; |
1118 |
< |
if (tail >= 0) { |
1119 |
< |
a = Arrays.copyOfRange(elements, head, tail, klazz); |
1118 |
> |
final int head = this.head, tail = this.tail, end; |
1119 |
> |
if ((end = tail + ((head <= tail) ? 0 : es.length)) >= 0) { |
1120 |
> |
// Uses null extension feature of copyOfRange |
1121 |
> |
a = Arrays.copyOfRange(es, head, end, klazz); |
1122 |
|
} else { |
1123 |
|
// integer overflow! |
1124 |
< |
a = Arrays.copyOfRange(elements, 0, size, klazz); |
1125 |
< |
System.arraycopy(elements, head, a, 0, capacity - head); |
1124 |
> |
a = Arrays.copyOfRange(es, 0, end - head, klazz); |
1125 |
> |
System.arraycopy(es, head, a, 0, es.length - head); |
1126 |
|
} |
1127 |
< |
if (tail - capacity > 0) |
1128 |
< |
System.arraycopy(elements, 0, a, capacity - head, tail - capacity); |
1127 |
> |
if (end != tail) |
1128 |
> |
System.arraycopy(es, 0, a, es.length - head, tail); |
1129 |
|
return a; |
1130 |
|
} |
1131 |
|
|
1167 |
|
*/ |
1168 |
|
@SuppressWarnings("unchecked") |
1169 |
|
public <T> T[] toArray(T[] a) { |
1170 |
< |
final int size = this.size; |
1171 |
< |
if (size > a.length) |
1170 |
> |
final int size; |
1171 |
> |
if ((size = size()) > a.length) |
1172 |
|
return toArray((Class<T[]>) a.getClass()); |
1173 |
< |
final Object[] elements = this.elements; |
1174 |
< |
final int capacity = elements.length; |
1175 |
< |
final int head = this.head, tail = head + size; |
1176 |
< |
if (capacity - tail >= 0) |
1177 |
< |
System.arraycopy(elements, head, a, 0, size); |
1063 |
< |
else { |
1064 |
< |
System.arraycopy(elements, head, a, 0, capacity - head); |
1065 |
< |
System.arraycopy(elements, 0, a, capacity - head, tail - capacity); |
1173 |
> |
final Object[] es = elements; |
1174 |
> |
for (int i = head, j = 0, len = Math.min(size, es.length - i); |
1175 |
> |
; i = 0, len = tail) { |
1176 |
> |
System.arraycopy(es, i, a, j, len); |
1177 |
> |
if ((j += len) == size) break; |
1178 |
|
} |
1179 |
|
if (size < a.length) |
1180 |
|
a[size] = null; |
1215 |
|
s.defaultWriteObject(); |
1216 |
|
|
1217 |
|
// Write out size |
1218 |
< |
s.writeInt(size); |
1218 |
> |
s.writeInt(size()); |
1219 |
|
|
1220 |
|
// Write out elements in order. |
1221 |
< |
final Object[] elements = this.elements; |
1222 |
< |
final int capacity = elements.length; |
1223 |
< |
for (int k = size, i = head; --k >= 0; i = inc(i, capacity)) |
1224 |
< |
s.writeObject(elements[i]); |
1221 |
> |
final Object[] es = elements; |
1222 |
> |
for (int i = head, end = tail, to = (i <= end) ? end : es.length; |
1223 |
> |
; i = 0, to = end) { |
1224 |
> |
for (; i < to; i++) |
1225 |
> |
s.writeObject(es[i]); |
1226 |
> |
if (to == end) break; |
1227 |
> |
} |
1228 |
|
} |
1229 |
|
|
1230 |
|
/** |
1239 |
|
s.defaultReadObject(); |
1240 |
|
|
1241 |
|
// Read in size and allocate array |
1242 |
< |
elements = new Object[size = s.readInt()]; |
1242 |
> |
int size = s.readInt(); |
1243 |
> |
SharedSecrets.getJavaObjectInputStreamAccess().checkArray(s, Object[].class, size + 1); |
1244 |
> |
elements = new Object[size + 1]; |
1245 |
> |
this.tail = size; |
1246 |
|
|
1247 |
|
// Read in all elements in the proper order. |
1248 |
|
for (int i = 0; i < size; i++) |
1250 |
|
} |
1251 |
|
|
1252 |
|
/** debugging */ |
1253 |
< |
private void checkInvariants() { |
1253 |
> |
void checkInvariants() { |
1254 |
> |
// Use head and tail fields with empty slot at tail strategy. |
1255 |
> |
// head == tail disambiguates to "empty". |
1256 |
|
try { |
1257 |
|
int capacity = elements.length; |
1258 |
< |
assert size >= 0 && size <= capacity; |
1259 |
< |
assert head >= 0 && ((capacity == 0 && head == 0 && size == 0) |
1260 |
< |
|| head < capacity); |
1261 |
< |
assert size == 0 |
1262 |
< |
|| (elements[head] != null && elements[tail()] != null); |
1263 |
< |
assert size == capacity |
1264 |
< |
|| (elements[dec(head, capacity)] == null |
1145 |
< |
&& elements[inc(tail(), capacity)] == null); |
1258 |
> |
// assert 0 <= head && head < capacity; |
1259 |
> |
// assert 0 <= tail && tail < capacity; |
1260 |
> |
// assert capacity > 0; |
1261 |
> |
// assert size() < capacity; |
1262 |
> |
// assert head == tail || elements[head] != null; |
1263 |
> |
// assert elements[tail] == null; |
1264 |
> |
// assert head == tail || elements[dec(tail, capacity)] != null; |
1265 |
|
} catch (Throwable t) { |
1266 |
< |
System.err.printf("head=%d size=%d capacity=%d%n", |
1267 |
< |
head, size, elements.length); |
1266 |
> |
System.err.printf("head=%d tail=%d capacity=%d%n", |
1267 |
> |
head, tail, elements.length); |
1268 |
|
System.err.printf("elements=%s%n", |
1269 |
|
Arrays.toString(elements)); |
1270 |
|
throw t; |