7 |
|
|
8 |
|
import java.io.Serializable; |
9 |
|
import java.util.function.Consumer; |
10 |
< |
import java.util.stream.Stream; |
10 |
> |
import java.util.function.Predicate; |
11 |
> |
import java.util.function.UnaryOperator; |
12 |
|
|
13 |
|
/** |
14 |
|
* Resizable-array implementation of the {@link Deque} interface. Array |
54 |
|
* Java Collections Framework</a>. |
55 |
|
* |
56 |
|
* @author Josh Bloch and Doug Lea |
56 |
– |
* @since 1.6 |
57 |
|
* @param <E> the type of elements held in this deque |
58 |
+ |
* @since 1.6 |
59 |
|
*/ |
60 |
|
public class ArrayDeque<E> extends AbstractCollection<E> |
61 |
|
implements Deque<E>, Cloneable, Serializable |
62 |
|
{ |
63 |
|
/** |
64 |
|
* The array in which the elements of the deque are stored. |
65 |
< |
* The capacity of the deque is the length of this array, which is |
66 |
< |
* always a power of two. The array is never allowed to become |
66 |
< |
* full, except transiently within an addX method where it is |
67 |
< |
* resized (see doubleCapacity) immediately upon becoming full, |
68 |
< |
* thus avoiding head and tail wrapping around to equal each |
69 |
< |
* other. We also guarantee that all array cells not holding |
70 |
< |
* deque elements are always null. |
65 |
> |
* We guarantee that all array cells not holding deque elements |
66 |
> |
* are always null. |
67 |
|
*/ |
68 |
< |
transient Object[] elements; // non-private to simplify nested class access |
68 |
> |
transient Object[] elements; |
69 |
|
|
70 |
|
/** |
71 |
|
* The index of the element at the head of the deque (which is the |
72 |
|
* element that would be removed by remove() or pop()); or an |
73 |
< |
* arbitrary number equal to tail if the deque is empty. |
73 |
> |
* arbitrary number 0 <= head < elements.length if the deque is empty. |
74 |
|
*/ |
75 |
|
transient int head; |
76 |
|
|
77 |
+ |
/** Number of elements in this collection. */ |
78 |
+ |
transient int size; |
79 |
+ |
|
80 |
|
/** |
81 |
< |
* The index at which the next element would be added to the tail |
82 |
< |
* of the deque (via addLast(E), add(E), or push(E)). |
81 |
> |
* The maximum size of array to allocate. |
82 |
> |
* Some VMs reserve some header words in an array. |
83 |
> |
* Attempts to allocate larger arrays may result in |
84 |
> |
* OutOfMemoryError: Requested array size exceeds VM limit |
85 |
|
*/ |
86 |
< |
transient int tail; |
86 |
> |
private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8; |
87 |
|
|
88 |
|
/** |
89 |
< |
* The minimum capacity that we'll use for a newly created deque. |
90 |
< |
* Must be a power of 2. |
89 |
> |
* Increases the capacity of this deque by at least the given amount. |
90 |
> |
* |
91 |
> |
* @param needed the required minimum extra capacity; must be positive |
92 |
|
*/ |
93 |
< |
private static final int MIN_INITIAL_CAPACITY = 8; |
93 |
> |
private void grow(int needed) { |
94 |
> |
// overflow-conscious code |
95 |
> |
// checkInvariants(); |
96 |
> |
final int oldCapacity = elements.length; |
97 |
> |
int newCapacity; |
98 |
> |
// Double size if small; else grow by 50% |
99 |
> |
int jump = (oldCapacity < 64) ? (oldCapacity + 2) : (oldCapacity >> 1); |
100 |
> |
if (jump < needed |
101 |
> |
|| (newCapacity = (oldCapacity + jump)) - MAX_ARRAY_SIZE > 0) |
102 |
> |
newCapacity = newCapacity(needed, jump); |
103 |
> |
elements = Arrays.copyOf(elements, newCapacity); |
104 |
> |
if (oldCapacity - head < size) { |
105 |
> |
// wrap around; slide first leg forward to end of array |
106 |
> |
int newSpace = newCapacity - oldCapacity; |
107 |
> |
System.arraycopy(elements, head, |
108 |
> |
elements, head + newSpace, |
109 |
> |
oldCapacity - head); |
110 |
> |
Arrays.fill(elements, head, head + newSpace, null); |
111 |
> |
head += newSpace; |
112 |
> |
} |
113 |
> |
// checkInvariants(); |
114 |
> |
} |
115 |
|
|
116 |
< |
// ****** Array allocation and resizing utilities ****** |
116 |
> |
/** Capacity calculation for edge conditions, especially overflow. */ |
117 |
> |
private int newCapacity(int needed, int jump) { |
118 |
> |
final int oldCapacity = elements.length, minCapacity; |
119 |
> |
if ((minCapacity = oldCapacity + needed) - MAX_ARRAY_SIZE > 0) { |
120 |
> |
if (minCapacity < 0) |
121 |
> |
throw new IllegalStateException("Sorry, deque too big"); |
122 |
> |
return Integer.MAX_VALUE; |
123 |
> |
} |
124 |
> |
if (needed > jump) |
125 |
> |
return minCapacity; |
126 |
> |
return (oldCapacity + jump - MAX_ARRAY_SIZE < 0) |
127 |
> |
? oldCapacity + jump |
128 |
> |
: MAX_ARRAY_SIZE; |
129 |
> |
} |
130 |
|
|
131 |
|
/** |
132 |
< |
* Allocates empty array to hold the given number of elements. |
132 |
> |
* Increases the internal storage of this collection, if necessary, |
133 |
> |
* to ensure that it can hold at least the given number of elements. |
134 |
|
* |
135 |
< |
* @param numElements the number of elements to hold |
135 |
> |
* @param minCapacity the desired minimum capacity |
136 |
> |
* @since TBD |
137 |
|
*/ |
138 |
< |
private void allocateElements(int numElements) { |
139 |
< |
int initialCapacity = MIN_INITIAL_CAPACITY; |
140 |
< |
// Find the best power of two to hold elements. |
141 |
< |
// Tests "<=" because arrays aren't kept full. |
104 |
< |
if (numElements >= initialCapacity) { |
105 |
< |
initialCapacity = numElements; |
106 |
< |
initialCapacity |= (initialCapacity >>> 1); |
107 |
< |
initialCapacity |= (initialCapacity >>> 2); |
108 |
< |
initialCapacity |= (initialCapacity >>> 4); |
109 |
< |
initialCapacity |= (initialCapacity >>> 8); |
110 |
< |
initialCapacity |= (initialCapacity >>> 16); |
111 |
< |
initialCapacity++; |
112 |
< |
|
113 |
< |
if (initialCapacity < 0) // Too many elements, must back off |
114 |
< |
initialCapacity >>>= 1;// Good luck allocating 2 ^ 30 elements |
115 |
< |
} |
116 |
< |
elements = new Object[initialCapacity]; |
138 |
> |
/* public */ void ensureCapacity(int minCapacity) { |
139 |
> |
if (minCapacity > elements.length) |
140 |
> |
grow(minCapacity - elements.length); |
141 |
> |
// checkInvariants(); |
142 |
|
} |
143 |
|
|
144 |
|
/** |
145 |
< |
* Doubles the capacity of this deque. Call only when full, i.e., |
146 |
< |
* when head and tail have wrapped around to become equal. |
145 |
> |
* Minimizes the internal storage of this collection. |
146 |
> |
* |
147 |
> |
* @since TBD |
148 |
|
*/ |
149 |
< |
private void doubleCapacity() { |
150 |
< |
assert head == tail; |
151 |
< |
int p = head; |
152 |
< |
int n = elements.length; |
153 |
< |
int r = n - p; // number of elements to the right of p |
154 |
< |
int newCapacity = n << 1; |
129 |
< |
if (newCapacity < 0) |
130 |
< |
throw new IllegalStateException("Sorry, deque too big"); |
131 |
< |
Object[] a = new Object[newCapacity]; |
132 |
< |
System.arraycopy(elements, p, a, 0, r); |
133 |
< |
System.arraycopy(elements, 0, a, r, p); |
134 |
< |
elements = a; |
135 |
< |
head = 0; |
136 |
< |
tail = n; |
149 |
> |
/* public */ void trimToSize() { |
150 |
> |
if (size < elements.length) { |
151 |
> |
elements = toArray(); |
152 |
> |
head = 0; |
153 |
> |
} |
154 |
> |
// checkInvariants(); |
155 |
|
} |
156 |
|
|
157 |
|
/** |
166 |
|
* Constructs an empty array deque with an initial capacity |
167 |
|
* sufficient to hold the specified number of elements. |
168 |
|
* |
169 |
< |
* @param numElements lower bound on initial capacity of the deque |
169 |
> |
* @param numElements lower bound on initial capacity of the deque |
170 |
|
*/ |
171 |
|
public ArrayDeque(int numElements) { |
172 |
< |
allocateElements(numElements); |
172 |
> |
elements = new Object[numElements]; |
173 |
|
} |
174 |
|
|
175 |
|
/** |
183 |
|
* @throws NullPointerException if the specified collection is null |
184 |
|
*/ |
185 |
|
public ArrayDeque(Collection<? extends E> c) { |
186 |
< |
allocateElements(c.size()); |
187 |
< |
addAll(c); |
186 |
> |
Object[] es = c.toArray(); |
187 |
> |
// defend against c.toArray (incorrectly) not returning Object[] |
188 |
> |
// (see e.g. https://bugs.openjdk.java.net/browse/JDK-6260652) |
189 |
> |
if (es.getClass() != Object[].class) |
190 |
> |
es = Arrays.copyOf(es, es.length, Object[].class); |
191 |
> |
for (Object obj : es) |
192 |
> |
Objects.requireNonNull(obj); |
193 |
> |
this.elements = es; |
194 |
> |
this.size = es.length; |
195 |
> |
} |
196 |
> |
|
197 |
> |
/** |
198 |
> |
* Increments i, mod modulus. |
199 |
> |
* Precondition and postcondition: 0 <= i < modulus. |
200 |
> |
*/ |
201 |
> |
static final int inc(int i, int modulus) { |
202 |
> |
if (++i >= modulus) i = 0; |
203 |
> |
return i; |
204 |
> |
} |
205 |
> |
|
206 |
> |
/** |
207 |
> |
* Decrements i, mod modulus. |
208 |
> |
* Precondition and postcondition: 0 <= i < modulus. |
209 |
> |
*/ |
210 |
> |
static final int dec(int i, int modulus) { |
211 |
> |
if (--i < 0) i = modulus - 1; |
212 |
> |
return i; |
213 |
> |
} |
214 |
> |
|
215 |
> |
/** |
216 |
> |
* Adds i and j, mod modulus. |
217 |
> |
* Precondition and postcondition: 0 <= i < modulus, 0 <= j <= modulus. |
218 |
> |
*/ |
219 |
> |
static final int add(int i, int j, int modulus) { |
220 |
> |
if ((i += j) - modulus >= 0) i -= modulus; |
221 |
> |
return i; |
222 |
> |
} |
223 |
> |
|
224 |
> |
/** |
225 |
> |
* Returns the array index of the last element. |
226 |
> |
* May return invalid index -1 if there are no elements. |
227 |
> |
*/ |
228 |
> |
final int tail() { |
229 |
> |
return add(head, size - 1, elements.length); |
230 |
> |
} |
231 |
> |
|
232 |
> |
/** |
233 |
> |
* Returns element at array index i. |
234 |
> |
*/ |
235 |
> |
@SuppressWarnings("unchecked") |
236 |
> |
private E elementAt(int i) { |
237 |
> |
return (E) elements[i]; |
238 |
> |
} |
239 |
> |
|
240 |
> |
/** |
241 |
> |
* A version of elementAt that checks for null elements. |
242 |
> |
* This check doesn't catch all possible comodifications, |
243 |
> |
* but does catch ones that corrupt traversal. It's a little |
244 |
> |
* surprising that javac allows this abuse of generics. |
245 |
> |
*/ |
246 |
> |
static final <E> E nonNullElementAt(Object[] es, int i) { |
247 |
> |
@SuppressWarnings("unchecked") E e = (E) es[i]; |
248 |
> |
if (e == null) |
249 |
> |
throw new ConcurrentModificationException(); |
250 |
> |
return e; |
251 |
|
} |
252 |
|
|
253 |
|
// The main insertion and extraction methods are addFirst, |
261 |
|
* @throws NullPointerException if the specified element is null |
262 |
|
*/ |
263 |
|
public void addFirst(E e) { |
264 |
< |
if (e == null) |
265 |
< |
throw new NullPointerException(); |
266 |
< |
elements[head = (head - 1) & (elements.length - 1)] = e; |
267 |
< |
if (head == tail) |
268 |
< |
doubleCapacity(); |
264 |
> |
// checkInvariants(); |
265 |
> |
Objects.requireNonNull(e); |
266 |
> |
Object[] es; |
267 |
> |
int capacity, h; |
268 |
> |
final int s; |
269 |
> |
if ((s = size) == (capacity = (es = elements).length)) { |
270 |
> |
grow(1); |
271 |
> |
capacity = (es = elements).length; |
272 |
> |
} |
273 |
> |
if ((h = head - 1) < 0) h = capacity - 1; |
274 |
> |
es[head = h] = e; |
275 |
> |
size = s + 1; |
276 |
> |
// checkInvariants(); |
277 |
|
} |
278 |
|
|
279 |
|
/** |
285 |
|
* @throws NullPointerException if the specified element is null |
286 |
|
*/ |
287 |
|
public void addLast(E e) { |
288 |
< |
if (e == null) |
289 |
< |
throw new NullPointerException(); |
290 |
< |
elements[tail] = e; |
291 |
< |
if ( (tail = (tail + 1) & (elements.length - 1)) == head) |
292 |
< |
doubleCapacity(); |
288 |
> |
// checkInvariants(); |
289 |
> |
Objects.requireNonNull(e); |
290 |
> |
Object[] es; |
291 |
> |
int capacity; |
292 |
> |
final int s; |
293 |
> |
if ((s = size) == (capacity = (es = elements).length)) { |
294 |
> |
grow(1); |
295 |
> |
capacity = (es = elements).length; |
296 |
> |
} |
297 |
> |
es[add(head, s, capacity)] = e; |
298 |
> |
size = s + 1; |
299 |
> |
// checkInvariants(); |
300 |
> |
} |
301 |
> |
|
302 |
> |
/** |
303 |
> |
* Adds all of the elements in the specified collection at the end |
304 |
> |
* of this deque, as if by calling {@link #addLast} on each one, |
305 |
> |
* in the order that they are returned by the collection's |
306 |
> |
* iterator. |
307 |
> |
* |
308 |
> |
* @param c the elements to be inserted into this deque |
309 |
> |
* @return {@code true} if this deque changed as a result of the call |
310 |
> |
* @throws NullPointerException if the specified collection or any |
311 |
> |
* of its elements are null |
312 |
> |
*/ |
313 |
> |
public boolean addAll(Collection<? extends E> c) { |
314 |
> |
final int s = size, needed = c.size() - (elements.length - s); |
315 |
> |
if (needed > 0) |
316 |
> |
grow(needed); |
317 |
> |
c.forEach((e) -> addLast(e)); |
318 |
> |
// checkInvariants(); |
319 |
> |
return size > s; |
320 |
|
} |
321 |
|
|
322 |
|
/** |
347 |
|
* @throws NoSuchElementException {@inheritDoc} |
348 |
|
*/ |
349 |
|
public E removeFirst() { |
350 |
< |
E x = pollFirst(); |
351 |
< |
if (x == null) |
350 |
> |
// checkInvariants(); |
351 |
> |
E e = pollFirst(); |
352 |
> |
if (e == null) |
353 |
|
throw new NoSuchElementException(); |
354 |
< |
return x; |
354 |
> |
return e; |
355 |
|
} |
356 |
|
|
357 |
|
/** |
358 |
|
* @throws NoSuchElementException {@inheritDoc} |
359 |
|
*/ |
360 |
|
public E removeLast() { |
361 |
< |
E x = pollLast(); |
362 |
< |
if (x == null) |
361 |
> |
// checkInvariants(); |
362 |
> |
E e = pollLast(); |
363 |
> |
if (e == null) |
364 |
|
throw new NoSuchElementException(); |
365 |
< |
return x; |
365 |
> |
return e; |
366 |
|
} |
367 |
|
|
368 |
|
public E pollFirst() { |
369 |
< |
int h = head; |
370 |
< |
@SuppressWarnings("unchecked") |
371 |
< |
E result = (E) elements[h]; |
254 |
< |
// Element is null if deque empty |
255 |
< |
if (result == null) |
369 |
> |
// checkInvariants(); |
370 |
> |
int s, h; |
371 |
> |
if ((s = size) <= 0) |
372 |
|
return null; |
373 |
< |
elements[h] = null; // Must null out slot |
374 |
< |
head = (h + 1) & (elements.length - 1); |
375 |
< |
return result; |
373 |
> |
final Object[] es = elements; |
374 |
> |
@SuppressWarnings("unchecked") E e = (E) es[h = head]; |
375 |
> |
es[h] = null; |
376 |
> |
if (++h >= es.length) h = 0; |
377 |
> |
head = h; |
378 |
> |
size = s - 1; |
379 |
> |
return e; |
380 |
|
} |
381 |
|
|
382 |
|
public E pollLast() { |
383 |
< |
int t = (tail - 1) & (elements.length - 1); |
384 |
< |
@SuppressWarnings("unchecked") |
385 |
< |
E result = (E) elements[t]; |
266 |
< |
if (result == null) |
383 |
> |
// checkInvariants(); |
384 |
> |
final int s, tail; |
385 |
> |
if ((s = size) <= 0) |
386 |
|
return null; |
387 |
< |
elements[t] = null; |
388 |
< |
tail = t; |
389 |
< |
return result; |
387 |
> |
final Object[] es = elements; |
388 |
> |
@SuppressWarnings("unchecked") |
389 |
> |
E e = (E) es[tail = add(head, s - 1, es.length)]; |
390 |
> |
es[tail] = null; |
391 |
> |
size = s - 1; |
392 |
> |
return e; |
393 |
|
} |
394 |
|
|
395 |
|
/** |
396 |
|
* @throws NoSuchElementException {@inheritDoc} |
397 |
|
*/ |
398 |
|
public E getFirst() { |
399 |
< |
@SuppressWarnings("unchecked") |
400 |
< |
E result = (E) elements[head]; |
401 |
< |
if (result == null) |
280 |
< |
throw new NoSuchElementException(); |
281 |
< |
return result; |
399 |
> |
// checkInvariants(); |
400 |
> |
if (size <= 0) throw new NoSuchElementException(); |
401 |
> |
return elementAt(head); |
402 |
|
} |
403 |
|
|
404 |
|
/** |
405 |
|
* @throws NoSuchElementException {@inheritDoc} |
406 |
|
*/ |
407 |
+ |
@SuppressWarnings("unchecked") |
408 |
|
public E getLast() { |
409 |
< |
@SuppressWarnings("unchecked") |
410 |
< |
E result = (E) elements[(tail - 1) & (elements.length - 1)]; |
411 |
< |
if (result == null) |
412 |
< |
throw new NoSuchElementException(); |
413 |
< |
return result; |
409 |
> |
// checkInvariants(); |
410 |
> |
final int s; |
411 |
> |
if ((s = size) <= 0) throw new NoSuchElementException(); |
412 |
> |
final Object[] es = elements; |
413 |
> |
return (E) es[add(head, s - 1, es.length)]; |
414 |
|
} |
415 |
|
|
295 |
– |
@SuppressWarnings("unchecked") |
416 |
|
public E peekFirst() { |
417 |
< |
// elements[head] is null if deque empty |
418 |
< |
return (E) elements[head]; |
417 |
> |
// checkInvariants(); |
418 |
> |
return (size <= 0) ? null : elementAt(head); |
419 |
|
} |
420 |
|
|
421 |
|
@SuppressWarnings("unchecked") |
422 |
|
public E peekLast() { |
423 |
< |
return (E) elements[(tail - 1) & (elements.length - 1)]; |
423 |
> |
// checkInvariants(); |
424 |
> |
final int s; |
425 |
> |
if ((s = size) <= 0) return null; |
426 |
> |
final Object[] es = elements; |
427 |
> |
return (E) es[add(head, s - 1, es.length)]; |
428 |
|
} |
429 |
|
|
430 |
|
/** |
441 |
|
*/ |
442 |
|
public boolean removeFirstOccurrence(Object o) { |
443 |
|
if (o != null) { |
444 |
< |
int mask = elements.length - 1; |
445 |
< |
int i = head; |
446 |
< |
for (Object x; (x = elements[i]) != null; i = (i + 1) & mask) { |
447 |
< |
if (o.equals(x)) { |
448 |
< |
delete(i); |
449 |
< |
return true; |
450 |
< |
} |
444 |
> |
final Object[] es = elements; |
445 |
> |
int i, end, to, todo; |
446 |
> |
todo = (end = (i = head) + size) |
447 |
> |
- (to = (es.length - end >= 0) ? end : es.length); |
448 |
> |
for (;; to = todo, i = 0, todo = 0) { |
449 |
> |
for (; i < to; i++) |
450 |
> |
if (o.equals(es[i])) { |
451 |
> |
delete(i); |
452 |
> |
return true; |
453 |
> |
} |
454 |
> |
if (todo == 0) break; |
455 |
|
} |
456 |
|
} |
457 |
|
return false; |
471 |
|
*/ |
472 |
|
public boolean removeLastOccurrence(Object o) { |
473 |
|
if (o != null) { |
474 |
< |
int mask = elements.length - 1; |
475 |
< |
int i = (tail - 1) & mask; |
476 |
< |
for (Object x; (x = elements[i]) != null; i = (i - 1) & mask) { |
477 |
< |
if (o.equals(x)) { |
478 |
< |
delete(i); |
479 |
< |
return true; |
480 |
< |
} |
474 |
> |
final Object[] es = elements; |
475 |
> |
int i, to, end, todo; |
476 |
> |
todo = (to = ((end = (i = tail()) - size) >= -1) ? end : -1) - end; |
477 |
> |
for (;; to = (i = es.length - 1) - todo, todo = 0) { |
478 |
> |
for (; i > to; i--) |
479 |
> |
if (o.equals(es[i])) { |
480 |
> |
delete(i); |
481 |
> |
return true; |
482 |
> |
} |
483 |
> |
if (todo == 0) break; |
484 |
|
} |
485 |
|
} |
486 |
|
return false; |
600 |
|
return removeFirst(); |
601 |
|
} |
602 |
|
|
472 |
– |
private void checkInvariants() { |
473 |
– |
assert elements[tail] == null; |
474 |
– |
assert head == tail ? elements[head] == null : |
475 |
– |
(elements[head] != null && |
476 |
– |
elements[(tail - 1) & (elements.length - 1)] != null); |
477 |
– |
assert elements[(head - 1) & (elements.length - 1)] == null; |
478 |
– |
} |
479 |
– |
|
603 |
|
/** |
604 |
< |
* Removes the element at the specified position in the elements array, |
605 |
< |
* adjusting head and tail as necessary. This can result in motion of |
606 |
< |
* elements backwards or forwards in the array. |
604 |
> |
* Removes the element at the specified position in the elements array. |
605 |
> |
* This can result in forward or backwards motion of array elements. |
606 |
> |
* We optimize for least element motion. |
607 |
|
* |
608 |
|
* <p>This method is called delete rather than remove to emphasize |
609 |
|
* that its semantics differ from those of {@link List#remove(int)}. |
610 |
|
* |
611 |
|
* @return true if elements moved backwards |
612 |
|
*/ |
613 |
< |
private boolean delete(int i) { |
614 |
< |
checkInvariants(); |
615 |
< |
final Object[] elements = this.elements; |
616 |
< |
final int mask = elements.length - 1; |
613 |
> |
boolean delete(int i) { |
614 |
> |
// checkInvariants(); |
615 |
> |
final Object[] es = elements; |
616 |
> |
final int capacity = es.length; |
617 |
|
final int h = head; |
618 |
< |
final int t = tail; |
619 |
< |
final int front = (i - h) & mask; |
620 |
< |
final int back = (t - i) & mask; |
498 |
< |
|
499 |
< |
// Invariant: head <= i < tail mod circularity |
500 |
< |
if (front >= ((t - h) & mask)) |
501 |
< |
throw new ConcurrentModificationException(); |
502 |
< |
|
503 |
< |
// Optimize for least element motion |
618 |
> |
int front; // number of elements before to-be-deleted elt |
619 |
> |
if ((front = i - h) < 0) front += capacity; |
620 |
> |
final int back = size - front - 1; // number of elements after |
621 |
|
if (front < back) { |
622 |
+ |
// move front elements forwards |
623 |
|
if (h <= i) { |
624 |
< |
System.arraycopy(elements, h, elements, h + 1, front); |
624 |
> |
System.arraycopy(es, h, es, h + 1, front); |
625 |
|
} else { // Wrap around |
626 |
< |
System.arraycopy(elements, 0, elements, 1, i); |
627 |
< |
elements[0] = elements[mask]; |
628 |
< |
System.arraycopy(elements, h, elements, h + 1, mask - h); |
626 |
> |
System.arraycopy(es, 0, es, 1, i); |
627 |
> |
es[0] = es[capacity - 1]; |
628 |
> |
System.arraycopy(es, h, es, h + 1, front - (i + 1)); |
629 |
|
} |
630 |
< |
elements[h] = null; |
631 |
< |
head = (h + 1) & mask; |
630 |
> |
es[h] = null; |
631 |
> |
if ((head = (h + 1)) >= capacity) head = 0; |
632 |
> |
size--; |
633 |
> |
// checkInvariants(); |
634 |
|
return false; |
635 |
|
} else { |
636 |
< |
if (i < t) { // Copy the null tail as well |
637 |
< |
System.arraycopy(elements, i + 1, elements, i, back); |
638 |
< |
tail = t - 1; |
636 |
> |
// move back elements backwards |
637 |
> |
int tail = tail(); |
638 |
> |
if (i <= tail) { |
639 |
> |
System.arraycopy(es, i + 1, es, i, back); |
640 |
|
} else { // Wrap around |
641 |
< |
System.arraycopy(elements, i + 1, elements, i, mask - i); |
642 |
< |
elements[mask] = elements[0]; |
643 |
< |
System.arraycopy(elements, 1, elements, 0, t); |
644 |
< |
tail = (t - 1) & mask; |
641 |
> |
int firstLeg = capacity - (i + 1); |
642 |
> |
System.arraycopy(es, i + 1, es, i, firstLeg); |
643 |
> |
es[capacity - 1] = es[0]; |
644 |
> |
System.arraycopy(es, 1, es, 0, back - firstLeg - 1); |
645 |
|
} |
646 |
+ |
es[tail] = null; |
647 |
+ |
size--; |
648 |
+ |
// checkInvariants(); |
649 |
|
return true; |
650 |
|
} |
651 |
|
} |
658 |
|
* @return the number of elements in this deque |
659 |
|
*/ |
660 |
|
public int size() { |
661 |
< |
return (tail - head) & (elements.length - 1); |
661 |
> |
return size; |
662 |
|
} |
663 |
|
|
664 |
|
/** |
667 |
|
* @return {@code true} if this deque contains no elements |
668 |
|
*/ |
669 |
|
public boolean isEmpty() { |
670 |
< |
return head == tail; |
670 |
> |
return size == 0; |
671 |
|
} |
672 |
|
|
673 |
|
/** |
687 |
|
} |
688 |
|
|
689 |
|
private class DeqIterator implements Iterator<E> { |
690 |
< |
/** |
691 |
< |
* Index of element to be returned by subsequent call to next. |
568 |
< |
*/ |
569 |
< |
private int cursor = head; |
690 |
> |
/** Index of element to be returned by subsequent call to next. */ |
691 |
> |
int cursor; |
692 |
|
|
693 |
< |
/** |
694 |
< |
* Tail recorded at construction (also in remove), to stop |
573 |
< |
* iterator and also to check for comodification. |
574 |
< |
*/ |
575 |
< |
private int fence = tail; |
693 |
> |
/** Number of elements yet to be returned. */ |
694 |
> |
int remaining = size; |
695 |
|
|
696 |
|
/** |
697 |
|
* Index of element returned by most recent call to next. |
698 |
|
* Reset to -1 if element is deleted by a call to remove. |
699 |
|
*/ |
700 |
< |
private int lastRet = -1; |
700 |
> |
int lastRet = -1; |
701 |
> |
|
702 |
> |
DeqIterator() { cursor = head; } |
703 |
|
|
704 |
< |
public boolean hasNext() { |
705 |
< |
return cursor != fence; |
704 |
> |
public final boolean hasNext() { |
705 |
> |
return remaining > 0; |
706 |
|
} |
707 |
|
|
708 |
|
public E next() { |
709 |
< |
if (cursor == fence) |
709 |
> |
if (remaining <= 0) |
710 |
|
throw new NoSuchElementException(); |
711 |
< |
@SuppressWarnings("unchecked") |
712 |
< |
E result = (E) elements[cursor]; |
592 |
< |
// This check doesn't catch all possible comodifications, |
593 |
< |
// but does catch the ones that corrupt traversal |
594 |
< |
if (tail != fence || result == null) |
595 |
< |
throw new ConcurrentModificationException(); |
711 |
> |
final Object[] es = elements; |
712 |
> |
E e = nonNullElementAt(es, cursor); |
713 |
|
lastRet = cursor; |
714 |
< |
cursor = (cursor + 1) & (elements.length - 1); |
715 |
< |
return result; |
714 |
> |
if (++cursor >= es.length) cursor = 0; |
715 |
> |
remaining--; |
716 |
> |
return e; |
717 |
> |
} |
718 |
> |
|
719 |
> |
void postDelete(boolean leftShifted) { |
720 |
> |
if (leftShifted) |
721 |
> |
if (--cursor < 0) cursor = elements.length - 1; |
722 |
|
} |
723 |
|
|
724 |
< |
public void remove() { |
724 |
> |
public final void remove() { |
725 |
|
if (lastRet < 0) |
726 |
|
throw new IllegalStateException(); |
727 |
< |
if (delete(lastRet)) { // if left-shifted, undo increment in next() |
605 |
< |
cursor = (cursor - 1) & (elements.length - 1); |
606 |
< |
fence = tail; |
607 |
< |
} |
727 |
> |
postDelete(delete(lastRet)); |
728 |
|
lastRet = -1; |
729 |
|
} |
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; |
739 |
+ |
} |
740 |
+ |
} |
741 |
+ |
} |
742 |
+ |
|
743 |
+ |
private class DescendingIterator extends DeqIterator { |
744 |
+ |
DescendingIterator() { cursor = tail(); } |
745 |
+ |
|
746 |
+ |
public final E next() { |
747 |
+ |
if (remaining <= 0) |
748 |
+ |
throw new NoSuchElementException(); |
749 |
+ |
final Object[] es = elements; |
750 |
+ |
E e = nonNullElementAt(es, cursor); |
751 |
+ |
lastRet = cursor; |
752 |
+ |
if (--cursor < 0) cursor = es.length - 1; |
753 |
+ |
remaining--; |
754 |
+ |
return e; |
755 |
+ |
} |
756 |
+ |
|
757 |
+ |
void postDelete(boolean leftShifted) { |
758 |
+ |
if (!leftShifted) |
759 |
+ |
if (++cursor >= elements.length) cursor = 0; |
760 |
+ |
} |
761 |
+ |
|
762 |
+ |
public final void forEachRemaining(Consumer<? super E> action) { |
763 |
+ |
Objects.requireNonNull(action); |
764 |
+ |
final int k; |
765 |
+ |
if ((k = remaining) > 0) { |
766 |
+ |
remaining = 0; |
767 |
+ |
final Object[] es = elements; |
768 |
+ |
int i, end, to, todo; |
769 |
+ |
todo = (to = ((end = (i = cursor) - k) >= -1) ? end : -1) - end; |
770 |
+ |
for (;; to = (i = es.length - 1) - todo, todo = 0) { |
771 |
+ |
for (; i > to; i--) |
772 |
+ |
action.accept(nonNullElementAt(es, i)); |
773 |
+ |
if (todo == 0) break; |
774 |
+ |
} |
775 |
+ |
if ((lastRet = cursor - (k - 1)) < 0) |
776 |
+ |
lastRet += es.length; |
777 |
+ |
} |
778 |
+ |
} |
779 |
|
} |
780 |
|
|
781 |
|
/** |
782 |
< |
* This class is nearly a mirror-image of DeqIterator, using tail |
783 |
< |
* instead of head for initial cursor, and head instead of tail |
784 |
< |
* for fence. |
785 |
< |
*/ |
786 |
< |
private class DescendingIterator implements Iterator<E> { |
787 |
< |
private int cursor = tail; |
788 |
< |
private int fence = head; |
789 |
< |
private int lastRet = -1; |
782 |
> |
* Creates a <em><a href="Spliterator.html#binding">late-binding</a></em> |
783 |
> |
* and <em>fail-fast</em> {@link Spliterator} over the elements in this |
784 |
> |
* deque. |
785 |
> |
* |
786 |
> |
* <p>The {@code Spliterator} reports {@link Spliterator#SIZED}, |
787 |
> |
* {@link Spliterator#SUBSIZED}, {@link Spliterator#ORDERED}, and |
788 |
> |
* {@link Spliterator#NONNULL}. Overriding implementations should document |
789 |
> |
* the reporting of additional characteristic values. |
790 |
> |
* |
791 |
> |
* @return a {@code Spliterator} over the elements in this deque |
792 |
> |
* @since 1.8 |
793 |
> |
*/ |
794 |
> |
public Spliterator<E> spliterator() { |
795 |
> |
return new ArrayDequeSpliterator(); |
796 |
> |
} |
797 |
|
|
798 |
< |
public boolean hasNext() { |
799 |
< |
return cursor != fence; |
798 |
> |
final class ArrayDequeSpliterator implements Spliterator<E> { |
799 |
> |
private int cursor; |
800 |
> |
private int remaining; // -1 until late-binding first use |
801 |
> |
|
802 |
> |
/** Constructs late-binding spliterator over all elements. */ |
803 |
> |
ArrayDequeSpliterator() { |
804 |
> |
this.remaining = -1; |
805 |
|
} |
806 |
|
|
807 |
< |
public E next() { |
808 |
< |
if (cursor == fence) |
809 |
< |
throw new NoSuchElementException(); |
810 |
< |
cursor = (cursor - 1) & (elements.length - 1); |
630 |
< |
@SuppressWarnings("unchecked") |
631 |
< |
E result = (E) elements[cursor]; |
632 |
< |
if (head != fence || result == null) |
633 |
< |
throw new ConcurrentModificationException(); |
634 |
< |
lastRet = cursor; |
635 |
< |
return result; |
807 |
> |
/** Constructs spliterator over the given slice. */ |
808 |
> |
ArrayDequeSpliterator(int cursor, int count) { |
809 |
> |
this.cursor = cursor; |
810 |
> |
this.remaining = count; |
811 |
|
} |
812 |
|
|
813 |
< |
public void remove() { |
814 |
< |
if (lastRet < 0) |
815 |
< |
throw new IllegalStateException(); |
816 |
< |
if (!delete(lastRet)) { |
817 |
< |
cursor = (cursor + 1) & (elements.length - 1); |
643 |
< |
fence = head; |
813 |
> |
/** Ensures late-binding initialization; then returns remaining. */ |
814 |
> |
private int remaining() { |
815 |
> |
if (remaining < 0) { |
816 |
> |
cursor = head; |
817 |
> |
remaining = size; |
818 |
|
} |
819 |
< |
lastRet = -1; |
819 |
> |
return remaining; |
820 |
> |
} |
821 |
> |
|
822 |
> |
public ArrayDequeSpliterator trySplit() { |
823 |
> |
final int mid; |
824 |
> |
if ((mid = remaining() >> 1) > 0) { |
825 |
> |
int oldCursor = cursor; |
826 |
> |
cursor = add(cursor, mid, elements.length); |
827 |
> |
remaining -= mid; |
828 |
> |
return new ArrayDequeSpliterator(oldCursor, mid); |
829 |
> |
} |
830 |
> |
return null; |
831 |
> |
} |
832 |
> |
|
833 |
> |
public void forEachRemaining(Consumer<? super E> action) { |
834 |
> |
Objects.requireNonNull(action); |
835 |
> |
final int k = remaining(); // side effect! |
836 |
> |
remaining = 0; |
837 |
> |
ArrayDeque.forEachRemaining(action, elements, cursor, k); |
838 |
> |
} |
839 |
> |
|
840 |
> |
public boolean tryAdvance(Consumer<? super E> action) { |
841 |
> |
Objects.requireNonNull(action); |
842 |
> |
final int k; |
843 |
> |
if ((k = remaining()) <= 0) |
844 |
> |
return false; |
845 |
> |
action.accept(nonNullElementAt(elements, cursor)); |
846 |
> |
if (++cursor >= elements.length) cursor = 0; |
847 |
> |
remaining = k - 1; |
848 |
> |
return true; |
849 |
> |
} |
850 |
> |
|
851 |
> |
public long estimateSize() { |
852 |
> |
return remaining(); |
853 |
> |
} |
854 |
> |
|
855 |
> |
public int characteristics() { |
856 |
> |
return Spliterator.NONNULL |
857 |
> |
| Spliterator.ORDERED |
858 |
> |
| Spliterator.SIZED |
859 |
> |
| Spliterator.SUBSIZED; |
860 |
> |
} |
861 |
> |
} |
862 |
> |
|
863 |
> |
@SuppressWarnings("unchecked") |
864 |
> |
public void forEach(Consumer<? super E> action) { |
865 |
> |
Objects.requireNonNull(action); |
866 |
> |
final Object[] es = elements; |
867 |
> |
int i, end, to, todo; |
868 |
> |
todo = (end = (i = head) + size) |
869 |
> |
- (to = (es.length - end >= 0) ? end : es.length); |
870 |
> |
for (;; to = todo, i = 0, todo = 0) { |
871 |
> |
for (; i < to; i++) |
872 |
> |
action.accept((E) es[i]); |
873 |
> |
if (todo == 0) break; |
874 |
> |
} |
875 |
> |
// checkInvariants(); |
876 |
> |
} |
877 |
> |
|
878 |
> |
/** |
879 |
> |
* Calls action on remaining elements, starting at index i and |
880 |
> |
* traversing in ascending order. A variant of forEach that also |
881 |
> |
* checks for concurrent modification, for use in iterators. |
882 |
> |
*/ |
883 |
> |
static <E> void forEachRemaining( |
884 |
> |
Consumer<? super E> action, Object[] es, int i, int remaining) { |
885 |
> |
int end, to, todo; |
886 |
> |
todo = (end = i + remaining) |
887 |
> |
- (to = (es.length - end >= 0) ? end : es.length); |
888 |
> |
for (;; to = todo, i = 0, todo = 0) { |
889 |
> |
for (; i < to; i++) |
890 |
> |
action.accept(nonNullElementAt(es, i)); |
891 |
> |
if (todo == 0) break; |
892 |
> |
} |
893 |
> |
} |
894 |
> |
|
895 |
> |
/** |
896 |
> |
* Replaces each element of this deque with the result of applying the |
897 |
> |
* operator to that element, as specified by {@link List#replaceAll}. |
898 |
> |
* |
899 |
> |
* @param operator the operator to apply to each element |
900 |
> |
* @since TBD |
901 |
> |
*/ |
902 |
> |
@SuppressWarnings("unchecked") |
903 |
> |
/* public */ void replaceAll(UnaryOperator<E> operator) { |
904 |
> |
Objects.requireNonNull(operator); |
905 |
> |
final Object[] es = elements; |
906 |
> |
int i, end, to, todo; |
907 |
> |
todo = (end = (i = head) + size) |
908 |
> |
- (to = (es.length - end >= 0) ? end : es.length); |
909 |
> |
for (;; to = todo, i = 0, todo = 0) { |
910 |
> |
for (; i < to; i++) |
911 |
> |
es[i] = operator.apply((E) es[i]); |
912 |
> |
if (todo == 0) break; |
913 |
> |
} |
914 |
> |
// checkInvariants(); |
915 |
> |
} |
916 |
> |
|
917 |
> |
/** |
918 |
> |
* @throws NullPointerException {@inheritDoc} |
919 |
> |
*/ |
920 |
> |
public boolean removeIf(Predicate<? super E> filter) { |
921 |
> |
Objects.requireNonNull(filter); |
922 |
> |
return bulkRemove(filter); |
923 |
> |
} |
924 |
> |
|
925 |
> |
/** |
926 |
> |
* @throws NullPointerException {@inheritDoc} |
927 |
> |
*/ |
928 |
> |
public boolean removeAll(Collection<?> c) { |
929 |
> |
Objects.requireNonNull(c); |
930 |
> |
return bulkRemove(e -> c.contains(e)); |
931 |
> |
} |
932 |
> |
|
933 |
> |
/** |
934 |
> |
* @throws NullPointerException {@inheritDoc} |
935 |
> |
*/ |
936 |
> |
public boolean retainAll(Collection<?> c) { |
937 |
> |
Objects.requireNonNull(c); |
938 |
> |
return bulkRemove(e -> !c.contains(e)); |
939 |
> |
} |
940 |
> |
|
941 |
> |
/** Implementation of bulk remove methods. */ |
942 |
> |
private boolean bulkRemove(Predicate<? super E> filter) { |
943 |
> |
// checkInvariants(); |
944 |
> |
final Object[] es = elements; |
945 |
> |
final int capacity = es.length; |
946 |
> |
int i = head, j = i, remaining = size, deleted = 0; |
947 |
> |
try { |
948 |
> |
for (; remaining > 0; remaining--) { |
949 |
> |
@SuppressWarnings("unchecked") E e = (E) es[i]; |
950 |
> |
if (filter.test(e)) |
951 |
> |
deleted++; |
952 |
> |
else { |
953 |
> |
if (j != i) |
954 |
> |
es[j] = e; |
955 |
> |
if (++j >= capacity) j = 0; |
956 |
> |
} |
957 |
> |
if (++i >= capacity) i = 0; |
958 |
> |
} |
959 |
> |
return deleted > 0; |
960 |
> |
} catch (Throwable ex) { |
961 |
> |
if (deleted > 0) |
962 |
> |
for (; remaining > 0; remaining--) { |
963 |
> |
es[j] = es[i]; |
964 |
> |
if (++i >= capacity) i = 0; |
965 |
> |
if (++j >= capacity) j = 0; |
966 |
> |
} |
967 |
> |
throw ex; |
968 |
> |
} finally { |
969 |
> |
size -= deleted; |
970 |
> |
circularClear(es, j, deleted); |
971 |
> |
// checkInvariants(); |
972 |
|
} |
973 |
|
} |
974 |
|
|
982 |
|
*/ |
983 |
|
public boolean contains(Object o) { |
984 |
|
if (o != null) { |
985 |
< |
int mask = elements.length - 1; |
986 |
< |
int i = head; |
987 |
< |
for (Object x; (x = elements[i]) != null; i = (i + 1) & mask) { |
988 |
< |
if (o.equals(x)) |
989 |
< |
return true; |
985 |
> |
final Object[] es = elements; |
986 |
> |
int i, end, to, todo; |
987 |
> |
todo = (end = (i = head) + size) |
988 |
> |
- (to = (es.length - end >= 0) ? end : es.length); |
989 |
> |
for (;; to = todo, i = 0, todo = 0) { |
990 |
> |
for (; i < to; i++) |
991 |
> |
if (o.equals(es[i])) |
992 |
> |
return true; |
993 |
> |
if (todo == 0) break; |
994 |
|
} |
995 |
|
} |
996 |
|
return false; |
1018 |
|
* The deque will be empty after this call returns. |
1019 |
|
*/ |
1020 |
|
public void clear() { |
1021 |
< |
int h = head; |
1022 |
< |
int t = tail; |
1023 |
< |
if (h != t) { // clear all cells |
1024 |
< |
head = tail = 0; |
1025 |
< |
int i = h; |
1026 |
< |
int mask = elements.length - 1; |
1027 |
< |
do { |
1028 |
< |
elements[i] = null; |
1029 |
< |
i = (i + 1) & mask; |
1030 |
< |
} while (i != t); |
1021 |
> |
circularClear(elements, head, size); |
1022 |
> |
size = head = 0; |
1023 |
> |
// checkInvariants(); |
1024 |
> |
} |
1025 |
> |
|
1026 |
> |
/** |
1027 |
> |
* Nulls out count elements, starting at array index from. |
1028 |
> |
*/ |
1029 |
> |
private static void circularClear(Object[] es, int from, int count) { |
1030 |
> |
int end, to, todo; |
1031 |
> |
todo = (end = from + count) |
1032 |
> |
- (to = (es.length - end >= 0) ? end : es.length); |
1033 |
> |
for (;; to = todo, from = 0, todo = 0) { |
1034 |
> |
Arrays.fill(es, from, to, null); |
1035 |
> |
if (todo == 0) break; |
1036 |
|
} |
1037 |
|
} |
1038 |
|
|
1050 |
|
* @return an array containing all of the elements in this deque |
1051 |
|
*/ |
1052 |
|
public Object[] toArray() { |
1053 |
< |
final int head = this.head; |
1054 |
< |
final int tail = this.tail; |
1055 |
< |
boolean wrap = (tail < head); |
1056 |
< |
int end = wrap ? tail + elements.length : tail; |
1057 |
< |
Object[] a = Arrays.copyOfRange(elements, head, end); |
1058 |
< |
if (wrap) |
1059 |
< |
System.arraycopy(elements, 0, a, elements.length - head, tail); |
1053 |
> |
return toArray(Object[].class); |
1054 |
> |
} |
1055 |
> |
|
1056 |
> |
private <T> T[] toArray(Class<T[]> klazz) { |
1057 |
> |
final Object[] es = elements; |
1058 |
> |
final int capacity = es.length; |
1059 |
> |
final int head = this.head, end = head + size; |
1060 |
> |
final T[] a; |
1061 |
> |
if (end >= 0) { |
1062 |
> |
a = Arrays.copyOfRange(es, head, end, klazz); |
1063 |
> |
} else { |
1064 |
> |
// integer overflow! |
1065 |
> |
a = Arrays.copyOfRange(es, 0, size, klazz); |
1066 |
> |
System.arraycopy(es, head, a, 0, capacity - head); |
1067 |
> |
} |
1068 |
> |
if (end - capacity > 0) |
1069 |
> |
System.arraycopy(es, 0, a, capacity - head, end - capacity); |
1070 |
|
return a; |
1071 |
|
} |
1072 |
|
|
1092 |
|
* The following code can be used to dump the deque into a newly |
1093 |
|
* allocated array of {@code String}: |
1094 |
|
* |
1095 |
< |
* <pre> {@code String[] y = x.toArray(new String[0]);}</pre> |
1095 |
> |
* <pre> {@code String[] y = x.toArray(new String[0]);}</pre> |
1096 |
|
* |
1097 |
|
* Note that {@code toArray(new Object[0])} is identical in function to |
1098 |
|
* {@code toArray()}. |
1108 |
|
*/ |
1109 |
|
@SuppressWarnings("unchecked") |
1110 |
|
public <T> T[] toArray(T[] a) { |
1111 |
< |
final int head = this.head; |
1112 |
< |
final int tail = this.tail; |
1113 |
< |
boolean wrap = (tail < head); |
1114 |
< |
int size = (tail - head) + (wrap ? elements.length : 0); |
1115 |
< |
int firstLeg = size - (wrap ? tail : 0); |
1116 |
< |
int len = a.length; |
1117 |
< |
if (size > len) { |
1118 |
< |
a = (T[]) Arrays.copyOfRange(elements, head, head + size, |
1119 |
< |
a.getClass()); |
775 |
< |
} else { |
776 |
< |
System.arraycopy(elements, head, a, 0, firstLeg); |
777 |
< |
if (size < len) |
778 |
< |
a[size] = null; |
1111 |
> |
final int size; |
1112 |
> |
if ((size = this.size) > a.length) |
1113 |
> |
return toArray((Class<T[]>) a.getClass()); |
1114 |
> |
final Object[] es = elements; |
1115 |
> |
int i, j, len, todo; |
1116 |
> |
todo = size - (len = Math.min(size, es.length - (i = head))); |
1117 |
> |
for (j = 0;; j += len, len = todo, todo = 0, i = 0) { |
1118 |
> |
System.arraycopy(es, i, a, j, len); |
1119 |
> |
if (todo == 0) break; |
1120 |
|
} |
1121 |
< |
if (wrap) |
1122 |
< |
System.arraycopy(elements, 0, a, firstLeg, tail); |
1121 |
> |
if (size < a.length) |
1122 |
> |
a[size] = null; |
1123 |
|
return a; |
1124 |
|
} |
1125 |
|
|
1157 |
|
s.defaultWriteObject(); |
1158 |
|
|
1159 |
|
// Write out size |
1160 |
< |
s.writeInt(size()); |
1160 |
> |
s.writeInt(size); |
1161 |
|
|
1162 |
|
// Write out elements in order. |
1163 |
< |
int mask = elements.length - 1; |
1164 |
< |
for (int i = head; i != tail; i = (i + 1) & mask) |
1165 |
< |
s.writeObject(elements[i]); |
1163 |
> |
final Object[] es = elements; |
1164 |
> |
int i, end, to, todo; |
1165 |
> |
todo = (end = (i = head) + size) |
1166 |
> |
- (to = (es.length - end >= 0) ? end : es.length); |
1167 |
> |
for (;; to = todo, i = 0, todo = 0) { |
1168 |
> |
for (; i < to; i++) |
1169 |
> |
s.writeObject(es[i]); |
1170 |
> |
if (todo == 0) break; |
1171 |
> |
} |
1172 |
|
} |
1173 |
|
|
1174 |
|
/** |
1183 |
|
s.defaultReadObject(); |
1184 |
|
|
1185 |
|
// Read in size and allocate array |
1186 |
< |
int size = s.readInt(); |
840 |
< |
allocateElements(size); |
841 |
< |
head = 0; |
842 |
< |
tail = size; |
1186 |
> |
elements = new Object[size = s.readInt()]; |
1187 |
|
|
1188 |
|
// Read in all elements in the proper order. |
1189 |
|
for (int i = 0; i < size; i++) |
1190 |
|
elements[i] = s.readObject(); |
1191 |
|
} |
1192 |
|
|
1193 |
< |
public Spliterator<E> spliterator() { |
1194 |
< |
return new DeqSpliterator<E>(this, -1, -1); |
1195 |
< |
} |
1196 |
< |
|
1197 |
< |
static final class DeqSpliterator<E> implements Spliterator<E> { |
1198 |
< |
private final ArrayDeque<E> deq; |
1199 |
< |
private int fence; // -1 until first use |
1200 |
< |
private int index; // current index, modified on traverse/split |
1201 |
< |
|
1202 |
< |
/** Creates new spliterator covering the given array and range */ |
1203 |
< |
DeqSpliterator(ArrayDeque<E> deq, int origin, int fence) { |
1204 |
< |
this.deq = deq; |
1205 |
< |
this.index = origin; |
1206 |
< |
this.fence = fence; |
1207 |
< |
} |
1208 |
< |
|
1209 |
< |
private int getFence() { // force initialization |
866 |
< |
int t; |
867 |
< |
if ((t = fence) < 0) { |
868 |
< |
t = fence = deq.tail; |
869 |
< |
index = deq.head; |
870 |
< |
} |
871 |
< |
return t; |
872 |
< |
} |
873 |
< |
|
874 |
< |
public Spliterator<E> trySplit() { |
875 |
< |
int t = getFence(), h = index, n = deq.elements.length; |
876 |
< |
if (h != t && ((h + 1) & (n - 1)) != t) { |
877 |
< |
if (h > t) |
878 |
< |
t += n; |
879 |
< |
int m = ((h + t) >>> 1) & (n - 1); |
880 |
< |
return new DeqSpliterator<>(deq, h, index = m); |
881 |
< |
} |
882 |
< |
return null; |
883 |
< |
} |
884 |
< |
|
885 |
< |
public void forEachRemaining(Consumer<? super E> consumer) { |
886 |
< |
if (consumer == null) |
887 |
< |
throw new NullPointerException(); |
888 |
< |
Object[] a = deq.elements; |
889 |
< |
int m = a.length - 1, f = getFence(), i = index; |
890 |
< |
index = f; |
891 |
< |
while (i != f) { |
892 |
< |
@SuppressWarnings("unchecked") E e = (E)a[i]; |
893 |
< |
i = (i + 1) & m; |
894 |
< |
if (e == null) |
895 |
< |
throw new ConcurrentModificationException(); |
896 |
< |
consumer.accept(e); |
897 |
< |
} |
898 |
< |
} |
899 |
< |
|
900 |
< |
public boolean tryAdvance(Consumer<? super E> consumer) { |
901 |
< |
if (consumer == null) |
902 |
< |
throw new NullPointerException(); |
903 |
< |
Object[] a = deq.elements; |
904 |
< |
int m = a.length - 1, f = getFence(), i = index; |
905 |
< |
if (i != fence) { |
906 |
< |
@SuppressWarnings("unchecked") E e = (E)a[i]; |
907 |
< |
index = (i + 1) & m; |
908 |
< |
if (e == null) |
909 |
< |
throw new ConcurrentModificationException(); |
910 |
< |
consumer.accept(e); |
911 |
< |
return true; |
912 |
< |
} |
913 |
< |
return false; |
914 |
< |
} |
915 |
< |
|
916 |
< |
public long estimateSize() { |
917 |
< |
int n = getFence() - index; |
918 |
< |
if (n < 0) |
919 |
< |
n += deq.elements.length; |
920 |
< |
return (long) n; |
921 |
< |
} |
922 |
< |
|
923 |
< |
@Override |
924 |
< |
public int characteristics() { |
925 |
< |
return Spliterator.ORDERED | Spliterator.SIZED | |
926 |
< |
Spliterator.NONNULL | Spliterator.SUBSIZED; |
1193 |
> |
/** debugging */ |
1194 |
> |
void checkInvariants() { |
1195 |
> |
try { |
1196 |
> |
int capacity = elements.length; |
1197 |
> |
// assert size >= 0 && size <= capacity; |
1198 |
> |
// assert head >= 0; |
1199 |
> |
// assert capacity == 0 || head < capacity; |
1200 |
> |
// assert size == 0 || elements[head] != null; |
1201 |
> |
// assert size == 0 || elements[tail()] != null; |
1202 |
> |
// assert size == capacity || elements[dec(head, capacity)] == null; |
1203 |
> |
// assert size == capacity || elements[inc(tail(), capacity)] == null; |
1204 |
> |
} catch (Throwable t) { |
1205 |
> |
System.err.printf("head=%d size=%d capacity=%d%n", |
1206 |
> |
head, size, elements.length); |
1207 |
> |
System.err.printf("elements=%s%n", |
1208 |
> |
Arrays.toString(elements)); |
1209 |
> |
throw t; |
1210 |
|
} |
1211 |
|
} |
1212 |
|
|