1 /*
2 * Copyright (c) 1997, 2020, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
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23 */
24
25 #ifndef SHARE_UTILITIES_GROWABLEARRAY_HPP
26 #define SHARE_UTILITIES_GROWABLEARRAY_HPP
27
28 #include "memory/allocation.hpp"
29 #include "oops/array.hpp"
30 #include "oops/oop.hpp"
31 #include "memory/iterator.hpp"
32 #include "utilities/debug.hpp"
33 #include "utilities/globalDefinitions.hpp"
34 #include "utilities/ostream.hpp"
35 #include "utilities/powerOfTwo.hpp"
36
37 // A growable array.
38
39 /*************************************************************************/
40 /* */
41 /* WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING */
42 /* */
43 /* Should you use GrowableArrays to contain handles you must be certain */
44 /* that the GrowableArray does not outlive the HandleMark that contains */
45 /* the handles. Since GrowableArrays are typically resource allocated */
46 /* the following is an example of INCORRECT CODE, */
47 /* */
48 /* ResourceMark rm; */
49 /* GrowableArray<Handle>* arr = new GrowableArray<Handle>(size); */
50 /* if (blah) { */
51 /* while (...) { */
52 /* HandleMark hm; */
53 /* ... */
54 /* Handle h(THREAD, some_oop); */
55 /* arr->append(h); */
56 /* } */
57 /* } */
58 /* if (arr->length() != 0 ) { */
59 /* oop bad_oop = arr->at(0)(); // Handle is BAD HERE. */
60 /* ... */
61 /* } */
62 /* */
63 /* If the GrowableArrays you are creating is C_Heap allocated then it */
64 /* should not hold handles since the handles could trivially try and */
65 /* outlive their HandleMark. In some situations you might need to do */
66 /* this and it would be legal but be very careful and see if you can do */
67 /* the code in some other manner. */
68 /* */
69 /*************************************************************************/
70
71 // Non-template base class responsible for handling the length and max.
72
73
74 class GrowableArrayBase : public ResourceObj {
75 friend class VMStructs;
76
77 protected:
78 // Current number of accessible elements
79 int _len;
80 // Current number of allocated elements
81 int _max;
82
83 GrowableArrayBase(int initial_max, int initial_len) :
84 _len(initial_len),
85 _max(initial_max) {
86 assert(_len >= 0 && _len <= _max, "initial_len too big");
87 }
88
89 ~GrowableArrayBase() {}
90
91 public:
92 int length() const { return _len; }
93 int max_length() const { return _max; }
94
95 bool is_empty() const { return _len == 0; }
96 bool is_nonempty() const { return _len != 0; }
97 bool is_full() const { return _len == _max; }
98
99 void clear() { _len = 0; }
100 void trunc_to(int length) {
101 assert(length <= _len,"cannot increase length");
102 _len = length;
103 }
104 };
105
106 template <typename E> class GrowableArrayIterator;
107 template <typename E, typename UnaryPredicate> class GrowableArrayFilterIterator;
108
109 // Extends GrowableArrayBase with a typed data array.
110 //
111 // E: Element type
112 //
113 // The "view" adds function that don't grow or deallocate
114 // the _data array, so there's no need for an allocator.
115 //
116 // The "view" can be used to type erase the allocator classes
117 // of GrowableArrayWithAllocator.
118 template <typename E>
119 class GrowableArrayView : public GrowableArrayBase {
120 protected:
121 E* _data; // data array
122
123 GrowableArrayView<E>(E* data, int initial_max, int initial_len) :
124 GrowableArrayBase(initial_max, initial_len), _data(data) {}
125
126 ~GrowableArrayView() {}
127
128 public:
129 const static GrowableArrayView EMPTY;
130
131 bool operator==(const GrowableArrayView<E>& rhs) const {
132 if (_len != rhs._len)
133 return false;
134 for (int i = 0; i < _len; i++) {
135 if (at(i) != rhs.at(i)) {
136 return false;
137 }
138 }
139 return true;
140 }
141
142 bool operator!=(const GrowableArrayView<E>& rhs) const {
143 return !(*this == rhs);
144 }
145
146 E& at(int i) {
147 assert(0 <= i && i < _len, "illegal index");
148 return _data[i];
149 }
150
151 E const& at(int i) const {
152 assert(0 <= i && i < _len, "illegal index");
153 return _data[i];
154 }
155
156 E* adr_at(int i) const {
157 assert(0 <= i && i < _len, "illegal index");
158 return &_data[i];
159 }
160
161 E first() const {
162 assert(_len > 0, "empty list");
163 return _data[0];
164 }
165
166 E top() const {
167 assert(_len > 0, "empty list");
168 return _data[_len-1];
169 }
170
171 E last() const {
172 return top();
173 }
174
175 GrowableArrayIterator<E> begin() const {
176 return GrowableArrayIterator<E>(this, 0);
177 }
178
179 GrowableArrayIterator<E> end() const {
180 return GrowableArrayIterator<E>(this, length());
181 }
182
183 E pop() {
184 assert(_len > 0, "empty list");
185 return _data[--_len];
186 }
187
188 void at_put(int i, const E& elem) {
189 assert(0 <= i && i < _len, "illegal index");
190 _data[i] = elem;
191 }
192
193 bool contains(const E& elem) const {
194 for (int i = 0; i < _len; i++) {
195 if (_data[i] == elem) return true;
196 }
197 return false;
198 }
199
200 int find(const E& elem) const {
201 for (int i = 0; i < _len; i++) {
202 if (_data[i] == elem) return i;
203 }
204 return -1;
205 }
206
207 int find_from_end(const E& elem) const {
208 for (int i = _len-1; i >= 0; i--) {
209 if (_data[i] == elem) return i;
210 }
211 return -1;
212 }
213
214 int find(void* token, bool f(void*, E)) const {
215 for (int i = 0; i < _len; i++) {
216 if (f(token, _data[i])) return i;
217 }
218 return -1;
219 }
220
221 int find_from_end(void* token, bool f(void*, E)) const {
222 // start at the end of the array
223 for (int i = _len-1; i >= 0; i--) {
224 if (f(token, _data[i])) return i;
225 }
226 return -1;
227 }
228
229 // Order preserving remove operations.
230
231 void remove(const E& elem) {
232 // Assuming that element does exist.
233 bool removed = remove_if_existing(elem);
234 if (removed) return;
235 ShouldNotReachHere();
236 }
237
238 bool remove_if_existing(const E& elem) {
239 // Returns TRUE if elem is removed.
240 for (int i = 0; i < _len; i++) {
241 if (_data[i] == elem) {
242 remove_at(i);
243 return true;
244 }
245 }
246 return false;
247 }
248
249 void remove_at(int index) {
250 assert(0 <= index && index < _len, "illegal index");
251 for (int j = index + 1; j < _len; j++) {
252 _data[j-1] = _data[j];
253 }
254 _len--;
255 }
256
257 // Remove all elements up to the index (exclusive). The order is preserved.
258 void remove_till(int idx) {
259 for (int i = 0, j = idx; j < length(); i++, j++) {
260 at_put(i, at(j));
261 }
262 trunc_to(length() - idx);
263 }
264
265 // The order is changed.
266 void delete_at(int index) {
267 assert(0 <= index && index < _len, "illegal index");
268 if (index < --_len) {
269 // Replace removed element with last one.
270 _data[index] = _data[_len];
271 }
272 }
273
274 void sort(int f(E*, E*)) {
275 qsort(_data, length(), sizeof(E), (_sort_Fn)f);
276 }
277 // sort by fixed-stride sub arrays:
278 void sort(int f(E*, E*), int stride) {
279 qsort(_data, length() / stride, sizeof(E) * stride, (_sort_Fn)f);
280 }
281
282 template <typename K, int compare(const K&, const E&)> int find_sorted(const K& key, bool& found) {
283 found = false;
284 int min = 0;
285 int max = length() - 1;
286
287 while (max >= min) {
288 int mid = (int)(((uint)max + min) / 2);
289 E value = at(mid);
290 int diff = compare(key, value);
291 if (diff > 0) {
292 min = mid + 1;
293 } else if (diff < 0) {
294 max = mid - 1;
295 } else {
296 found = true;
297 return mid;
298 }
299 }
300 return min;
301 }
302
303 template <typename K>
304 int find_sorted(CompareClosure<E>* cc, const K& key, bool& found) {
305 found = false;
306 int min = 0;
307 int max = length() - 1;
308
309 while (max >= min) {
310 int mid = (int)(((uint)max + min) / 2);
311 E value = at(mid);
312 int diff = cc->do_compare(key, value);
313 if (diff > 0) {
314 min = mid + 1;
315 } else if (diff < 0) {
316 max = mid - 1;
317 } else {
318 found = true;
319 return mid;
320 }
321 }
322 return min;
323 }
324
325 size_t data_size_in_bytes() const {
326 return _len * sizeof(E);
327 }
328
329 void print() const {
330 tty->print("Growable Array " INTPTR_FORMAT, p2i(this));
331 tty->print(": length %d (_max %d) { ", _len, _max);
332 for (int i = 0; i < _len; i++) {
333 tty->print(INTPTR_FORMAT " ", *(intptr_t*)&(_data[i]));
334 }
335 tty->print("}\n");
336 }
337 };
338
339 template<typename E>
340 const GrowableArrayView<E> GrowableArrayView<E>::EMPTY(nullptr, 0, 0);
341
342 // GrowableArrayWithAllocator extends the "view" with
343 // the capability to grow and deallocate the data array.
344 //
345 // The allocator responsibility is delegated to the sub-class.
346 //
347 // Derived: The sub-class responsible for allocation / deallocation
348 // - E* Derived::allocate() - member function responsible for allocation
349 // - void Derived::deallocate(E*) - member function responsible for deallocation
350 template <typename E, typename Derived>
351 class GrowableArrayWithAllocator : public GrowableArrayView<E> {
352 friend class VMStructs;
353
354 void grow(int j);
355
356 protected:
357 GrowableArrayWithAllocator(E* data, int initial_max) :
358 GrowableArrayView<E>(data, initial_max, 0) {
359 for (int i = 0; i < initial_max; i++) {
360 ::new ((void*)&data[i]) E();
361 }
362 }
363
364 GrowableArrayWithAllocator(E* data, int initial_max, int initial_len, const E& filler) :
365 GrowableArrayView<E>(data, initial_max, initial_len) {
366 int i = 0;
367 for (; i < initial_len; i++) {
368 ::new ((void*)&data[i]) E(filler);
369 }
370 for (; i < initial_max; i++) {
371 ::new ((void*)&data[i]) E();
372 }
373 }
374
375 ~GrowableArrayWithAllocator() {}
376
377 public:
378 int append(const E& elem) {
379 if (this->_len == this->_max) grow(this->_len);
380 int idx = this->_len++;
381 this->_data[idx] = elem;
382 return idx;
383 }
384
385 bool append_if_missing(const E& elem) {
386 // Returns TRUE if elem is added.
387 bool missed = !this->contains(elem);
388 if (missed) append(elem);
389 return missed;
390 }
391
392 void push(const E& elem) { append(elem); }
393
394 E at_grow(int i, const E& fill = E()) {
395 assert(0 <= i, "negative index");
396 if (i >= this->_len) {
397 if (i >= this->_max) grow(i);
398 for (int j = this->_len; j <= i; j++)
399 this->_data[j] = fill;
400 this->_len = i+1;
401 }
402 return this->_data[i];
403 }
404
405 void at_put_grow(int i, const E& elem, const E& fill = E()) {
406 assert(0 <= i, "negative index");
407 if (i >= this->_len) {
408 if (i >= this->_max) grow(i);
409 for (int j = this->_len; j < i; j++)
410 this->_data[j] = fill;
411 this->_len = i+1;
412 }
413 this->_data[i] = elem;
414 }
415
416 // inserts the given element before the element at index i
417 void insert_before(const int idx, const E& elem) {
418 assert(0 <= idx && idx <= this->_len, "illegal index");
419 if (this->_len == this->_max) grow(this->_len);
420 for (int j = this->_len - 1; j >= idx; j--) {
421 this->_data[j + 1] = this->_data[j];
422 }
423 this->_len++;
424 this->_data[idx] = elem;
425 }
426
427 void insert_before(const int idx, const GrowableArrayView<E>* array) {
428 assert(0 <= idx && idx <= this->_len, "illegal index");
429 int array_len = array->length();
430 int new_len = this->_len + array_len;
431 if (new_len >= this->_max) grow(new_len);
432
433 for (int j = this->_len - 1; j >= idx; j--) {
434 this->_data[j + array_len] = this->_data[j];
435 }
436
437 for (int j = 0; j < array_len; j++) {
438 this->_data[idx + j] = array->at(j);
439 }
440
441 this->_len += array_len;
442 }
443
444 void appendAll(const GrowableArrayView<E>* l) {
445 for (int i = 0; i < l->length(); i++) {
446 this->at_put_grow(this->_len, l->at(i), E());
447 }
448 }
449
450 void appendAll(const Array<E>* l) {
451 for (int i = 0; i < l->length(); i++) {
452 this->at_put_grow(this->_len, l->at(i), E());
453 }
454 }
455
456 // Binary search and insertion utility. Search array for element
457 // matching key according to the static compare function. Insert
458 // that element if not already in the list. Assumes the list is
459 // already sorted according to compare function.
460 template <int compare(const E&, const E&)> E insert_sorted(const E& key) {
461 bool found;
462 int location = GrowableArrayView<E>::template find_sorted<E, compare>(key, found);
463 if (!found) {
464 insert_before(location, key);
465 }
466 return this->at(location);
467 }
468
469 E insert_sorted(CompareClosure<E>* cc, const E& key) {
470 bool found;
471 int location = find_sorted(cc, key, found);
472 if (!found) {
473 insert_before(location, key);
474 }
475 return this->at(location);
476 }
477
478 void swap(GrowableArrayWithAllocator<E, Derived>* other) {
479 ::swap(this->_data, other->_data);
480 ::swap(this->_len, other->_len);
481 ::swap(this->_max, other->_max);
482 }
483
484 void clear_and_deallocate();
485 };
486
487 template <typename E, typename Derived>
488 void GrowableArrayWithAllocator<E, Derived>::grow(int j) {
489 int old_max = this->_max;
490 // grow the array by increasing _max to the first power of two larger than the size we need
491 this->_max = next_power_of_2((uint32_t)j);
492 // j < _max
493 E* newData = static_cast<Derived*>(this)->allocate();
494 int i = 0;
495 for ( ; i < this->_len; i++) ::new ((void*)&newData[i]) E(this->_data[i]);
496 for ( ; i < this->_max; i++) ::new ((void*)&newData[i]) E();
497 for (i = 0; i < old_max; i++) this->_data[i].~E();
498 if (this->_data != NULL) {
499 static_cast<Derived*>(this)->deallocate(this->_data);
500 }
501 this->_data = newData;
502 }
503
504 template <typename E, typename Derived>
505 void GrowableArrayWithAllocator<E, Derived>::clear_and_deallocate() {
506 if (this->_data != NULL) {
507 for (int i = 0; i < this->_max; i++) {
508 this->_data[i].~E();
509 }
510 static_cast<Derived*>(this)->deallocate(this->_data);
511 this->_data = NULL;
512 }
513 this->_len = 0;
514 this->_max = 0;
515 }
516
517 class GrowableArrayResourceAllocator {
518 public:
519 static void* allocate(int max, int element_size);
520 };
521
522 // Arena allocator
523 class GrowableArrayArenaAllocator {
524 public:
525 static void* allocate(int max, int element_size, Arena* arena);
526 };
527
528 // CHeap allocator
529 class GrowableArrayCHeapAllocator {
530 public:
531 static void* allocate(int max, int element_size, MEMFLAGS memflags);
532 static void deallocate(void* mem);
533 };
534
535 #ifdef ASSERT
536
537 // Checks resource allocation nesting
538 class GrowableArrayNestingCheck {
539 // resource area nesting at creation
540 int _nesting;
541
542 public:
543 GrowableArrayNestingCheck(bool on_stack);
544
545 void on_stack_alloc() const;
546 };
547
548 #endif // ASSERT
549
550 // Encodes where the backing array is allocated
551 // and performs necessary checks.
552 class GrowableArrayMetadata {
553 uintptr_t _bits;
554
555 // resource area nesting at creation
556 debug_only(GrowableArrayNestingCheck _nesting_check;)
557
558 uintptr_t bits(MEMFLAGS memflags) const {
559 if (memflags == mtNone) {
560 // Stack allocation
561 return 0;
562 }
563
564 // CHeap allocation
565 return (uintptr_t(memflags) << 1) | 1;
566 }
567
568 uintptr_t bits(Arena* arena) const {
569 return uintptr_t(arena);
570 }
571
572 public:
573 GrowableArrayMetadata(Arena* arena) :
574 _bits(bits(arena))
575 debug_only(COMMA _nesting_check(on_stack())) {
576 }
577
578 GrowableArrayMetadata(MEMFLAGS memflags) :
579 _bits(bits(memflags))
580 debug_only(COMMA _nesting_check(on_stack())) {
581 }
582
583 #ifdef ASSERT
584 GrowableArrayMetadata(const GrowableArrayMetadata& other) :
585 _bits(other._bits),
586 _nesting_check(other._nesting_check) {
587 assert(!on_C_heap(), "Copying of CHeap arrays not supported");
588 assert(!other.on_C_heap(), "Copying of CHeap arrays not supported");
589 }
590
591 GrowableArrayMetadata& operator=(const GrowableArrayMetadata& other) {
592 _bits = other._bits;
593 _nesting_check = other._nesting_check;
594 assert(!on_C_heap(), "Assignment of CHeap arrays not supported");
595 assert(!other.on_C_heap(), "Assignment of CHeap arrays not supported");
596 return *this;
597 }
598
599 void init_checks(const GrowableArrayBase* array) const;
600 void on_stack_alloc_check() const;
601 #endif // ASSERT
602
603 bool on_C_heap() const { return (_bits & 1) == 1; }
604 bool on_stack () const { return _bits == 0; }
605 bool on_arena () const { return (_bits & 1) == 0 && _bits != 0; }
606
607 Arena* arena() const { return (Arena*)_bits; }
608 MEMFLAGS memflags() const { return MEMFLAGS(_bits >> 1); }
609 };
610
611 // THE GrowableArray.
612 //
613 // Supports multiple allocation strategies:
614 // - Resource stack allocation: if memflags == mtNone
615 // - CHeap allocation: if memflags != mtNone
616 // - Arena allocation: if an arena is provided
617 //
618 // There are some drawbacks of using GrowableArray, that are removed in some
619 // of the other implementations of GrowableArrayWithAllocator sub-classes:
620 //
621 // Memory overhead: The multiple allocation strategies uses extra metadata
622 // embedded in the instance.
623 //
624 // Strict allocation locations: There are rules about where the GrowableArray
625 // instance is allocated, that depends on where the data array is allocated.
626 // See: init_checks.
627
628 template <typename E>
629 class GrowableArray : public GrowableArrayWithAllocator<E, GrowableArray<E> > {
630 friend class GrowableArrayWithAllocator<E, GrowableArray<E> >;
631 friend class GrowableArrayTest;
632
633 static E* allocate(int max) {
634 return (E*)GrowableArrayResourceAllocator::allocate(max, sizeof(E));
635 }
636
637 static E* allocate(int max, MEMFLAGS memflags) {
638 if (memflags != mtNone) {
639 return (E*)GrowableArrayCHeapAllocator::allocate(max, sizeof(E), memflags);
640 }
641
642 return (E*)GrowableArrayResourceAllocator::allocate(max, sizeof(E));
643 }
644
645 static E* allocate(int max, Arena* arena) {
646 return (E*)GrowableArrayArenaAllocator::allocate(max, sizeof(E), arena);
647 }
648
649 GrowableArrayMetadata _metadata;
650
651 void init_checks() const { debug_only(_metadata.init_checks(this);) }
652
653 // Where are we going to allocate memory?
654 bool on_C_heap() const { return _metadata.on_C_heap(); }
655 bool on_stack () const { return _metadata.on_stack(); }
656 bool on_arena () const { return _metadata.on_arena(); }
657
658 E* allocate() {
659 if (on_stack()) {
660 debug_only(_metadata.on_stack_alloc_check());
661 return allocate(this->_max);
662 }
663
664 if (on_C_heap()) {
665 return allocate(this->_max, _metadata.memflags());
666 }
667
668 assert(on_arena(), "Sanity");
669 return allocate(this->_max, _metadata.arena());
670 }
671
672 void deallocate(E* mem) {
673 if (on_C_heap()) {
674 GrowableArrayCHeapAllocator::deallocate(mem);
675 }
676 }
677
678 public:
679 GrowableArray(int initial_max = 2, MEMFLAGS memflags = mtNone) :
680 GrowableArrayWithAllocator<E, GrowableArray<E> >(
681 allocate(initial_max, memflags),
682 initial_max),
683 _metadata(memflags) {
684 init_checks();
685 }
686
687 GrowableArray(int initial_max, int initial_len, const E& filler, MEMFLAGS memflags = mtNone) :
688 GrowableArrayWithAllocator<E, GrowableArray<E> >(
689 allocate(initial_max, memflags),
690 initial_max, initial_len, filler),
691 _metadata(memflags) {
692 init_checks();
693 }
694
695 GrowableArray(Arena* arena, int initial_max, int initial_len, const E& filler) :
696 GrowableArrayWithAllocator<E, GrowableArray<E> >(
697 allocate(initial_max, arena),
698 initial_max, initial_len, filler),
699 _metadata(arena) {
700 init_checks();
701 }
702
703 ~GrowableArray() {
704 if (on_C_heap()) {
705 this->clear_and_deallocate();
706 }
707 }
708 };
709
710 // Leaner GrowableArray for CHeap backed data arrays, with compile-time decided MEMFLAGS.
711 template <typename E, MEMFLAGS F>
712 class GrowableArrayCHeap : public GrowableArrayWithAllocator<E, GrowableArrayCHeap<E, F> > {
713 friend class GrowableArrayWithAllocator<E, GrowableArrayCHeap<E, F> >;
714
715 STATIC_ASSERT(F != mtNone);
716
717 static E* allocate(int max, MEMFLAGS flags) {
718 if (max == 0) {
719 return NULL;
720 }
721
722 return (E*)GrowableArrayCHeapAllocator::allocate(max, sizeof(E), flags);
723 }
724
725 NONCOPYABLE(GrowableArrayCHeap);
726
727 E* allocate() {
728 return allocate(this->_max, F);
729 }
730
731 void deallocate(E* mem) {
732 GrowableArrayCHeapAllocator::deallocate(mem);
733 }
734
735 public:
736 GrowableArrayCHeap(int initial_max = 0) :
737 GrowableArrayWithAllocator<E, GrowableArrayCHeap<E, F> >(
738 allocate(initial_max, F),
739 initial_max) {}
740
741 GrowableArrayCHeap(int initial_max, int initial_len, const E& filler) :
742 GrowableArrayWithAllocator<E, GrowableArrayCHeap<E, F> >(
743 allocate(initial_max, F),
744 initial_max, initial_len, filler) {}
745
746 ~GrowableArrayCHeap() {
747 this->clear_and_deallocate();
748 }
749
750 void* operator new(size_t size) throw() {
751 return ResourceObj::operator new(size, ResourceObj::C_HEAP, F);
752 }
753
754 void* operator new(size_t size, const std::nothrow_t& nothrow_constant) throw() {
755 return ResourceObj::operator new(size, nothrow_constant, ResourceObj::C_HEAP, F);
756 }
757 };
758
759 // Custom STL-style iterator to iterate over GrowableArrays
760 // It is constructed by invoking GrowableArray::begin() and GrowableArray::end()
761 template <typename E>
762 class GrowableArrayIterator : public StackObj {
763 friend class GrowableArrayView<E>;
764 template <typename F, typename UnaryPredicate> friend class GrowableArrayFilterIterator;
765
766 private:
767 const GrowableArrayView<E>* _array; // GrowableArray we iterate over
768 int _position; // The current position in the GrowableArray
769
770 // Private constructor used in GrowableArray::begin() and GrowableArray::end()
771 GrowableArrayIterator(const GrowableArrayView<E>* array, int position) : _array(array), _position(position) {
772 assert(0 <= position && position <= _array->length(), "illegal position");
773 }
774
775 public:
776 GrowableArrayIterator() : _array(NULL), _position(0) { }
777 GrowableArrayIterator<E>& operator++() { ++_position; return *this; }
778 E operator*() { return _array->at(_position); }
779
780 bool operator==(const GrowableArrayIterator<E>& rhs) {
781 assert(_array == rhs._array, "iterator belongs to different array");
782 return _position == rhs._position;
783 }
784
785 bool operator!=(const GrowableArrayIterator<E>& rhs) {
786 assert(_array == rhs._array, "iterator belongs to different array");
787 return _position != rhs._position;
788 }
789 };
790
791 // Custom STL-style iterator to iterate over elements of a GrowableArray that satisfy a given predicate
792 template <typename E, class UnaryPredicate>
793 class GrowableArrayFilterIterator : public StackObj {
794 friend class GrowableArrayView<E>;
795
796 private:
797 const GrowableArrayView<E>* _array; // GrowableArray we iterate over
798 int _position; // Current position in the GrowableArray
799 UnaryPredicate _predicate; // Unary predicate the elements of the GrowableArray should satisfy
800
801 public:
802 GrowableArrayFilterIterator(const GrowableArray<E>* array, UnaryPredicate filter_predicate) :
803 _array(array), _position(0), _predicate(filter_predicate) {
804 // Advance to first element satisfying the predicate
805 while(!at_end() && !_predicate(_array->at(_position))) {
806 ++_position;
807 }
808 }
809
810 GrowableArrayFilterIterator<E, UnaryPredicate>& operator++() {
811 do {
812 // Advance to next element satisfying the predicate
813 ++_position;
814 } while(!at_end() && !_predicate(_array->at(_position)));
815 return *this;
816 }
817
818 E operator*() { return _array->at(_position); }
819
820 bool operator==(const GrowableArrayIterator<E>& rhs) {
821 assert(_array == rhs._array, "iterator belongs to different array");
822 return _position == rhs._position;
823 }
824
825 bool operator!=(const GrowableArrayIterator<E>& rhs) {
826 assert(_array == rhs._array, "iterator belongs to different array");
827 return _position != rhs._position;
828 }
829
830 bool operator==(const GrowableArrayFilterIterator<E, UnaryPredicate>& rhs) {
831 assert(_array == rhs._array, "iterator belongs to different array");
832 return _position == rhs._position;
833 }
834
835 bool operator!=(const GrowableArrayFilterIterator<E, UnaryPredicate>& rhs) {
836 assert(_array == rhs._array, "iterator belongs to different array");
837 return _position != rhs._position;
838 }
839
840 bool at_end() const {
841 return _array == NULL || _position == _array->end()._position;
842 }
843 };
844
845 // Arrays for basic types
846 typedef GrowableArray<int> intArray;
847 typedef GrowableArray<int> intStack;
848 typedef GrowableArray<bool> boolArray;
849
850 #endif // SHARE_UTILITIES_GROWABLEARRAY_HPP