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 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
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).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
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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 "memory/iterator.hpp"
30 #include "utilities/debug.hpp"
31 #include "utilities/globalDefinitions.hpp"
32 #include "utilities/ostream.hpp"
33 #include "utilities/powerOfTwo.hpp"
34
35 // A growable array.
36
37 /*************************************************************************/
38 /* */
39 /* WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING */
40 /* */
41 /* Should you use GrowableArrays to contain handles you must be certain */
42 /* that the GrowableArray does not outlive the HandleMark that contains */
43 /* the handles. Since GrowableArrays are typically resource allocated */
44 /* the following is an example of INCORRECT CODE, */
45 /* */
46 /* ResourceMark rm; */
47 /* GrowableArray<Handle>* arr = new GrowableArray<Handle>(size); */
48 /* if (blah) { */
49 /* while (...) { */
50 /* HandleMark hm; */
51 /* ... */
52 /* Handle h(THREAD, some_oop); */
53 /* arr->append(h); */
54 /* } */
55 /* } */
56 /* if (arr->length() != 0 ) { */
57 /* oop bad_oop = arr->at(0)(); // Handle is BAD HERE. */
58 /* ... */
59 /* } */
60 /* */
61 /* If the GrowableArrays you are creating is C_Heap allocated then it */
62 /* should not hold handles since the handles could trivially try and */
63 /* outlive their HandleMark. In some situations you might need to do */
64 /* this and it would be legal but be very careful and see if you can do */
65 /* the code in some other manner. */
66 /* */
67 /*************************************************************************/
68
69 // Non-template base class responsible for handling the length and max.
70
71
72 class GrowableArrayBase : public ResourceObj {
73 friend class VMStructs;
74
75 protected:
76 // Current number of accessible elements
77 int _len;
78 // Current number of allocated elements
79 int _max;
80
81 GrowableArrayBase(int initial_max, int initial_len) :
82 _len(initial_len),
83 _max(initial_max) {
84 assert(_len >= 0 && _len <= _max, "initial_len too big");
85 }
86
87 ~GrowableArrayBase() {}
88
89 public:
90 int length() const { return _len; }
91 int max_length() const { return _max; }
92
93 bool is_empty() const { return _len == 0; }
94 bool is_nonempty() const { return _len != 0; }
95 bool is_full() const { return _len == _max; }
96
97 void clear() { _len = 0; }
98 void trunc_to(int length) {
99 assert(length <= _len,"cannot increase length");
100 _len = length;
101 }
102 };
103
104 template <typename E> class GrowableArrayIterator;
105 template <typename E, typename UnaryPredicate> class GrowableArrayFilterIterator;
106
107 // Extends GrowableArrayBase with a typed data array.
108 //
109 // E: Element type
110 //
111 // The "view" adds function that don't grow or deallocate
112 // the _data array, so there's no need for an allocator.
113 //
114 // The "view" can be used to type erase the allocator classes
115 // of GrowableArrayWithAllocator.
116 template <typename E>
117 class GrowableArrayView : public GrowableArrayBase {
118 protected:
119 E* _data; // data array
120
121 GrowableArrayView<E>(E* data, int initial_max, int initial_len) :
122 GrowableArrayBase(initial_max, initial_len), _data(data) {}
123
124 ~GrowableArrayView() {}
125
126 public:
127 const static GrowableArrayView EMPTY;
128
129 bool operator==(const GrowableArrayView<E>& rhs) const {
130 if (_len != rhs._len)
131 return false;
132 for (int i = 0; i < _len; i++) {
133 if (at(i) != rhs.at(i)) {
134 return false;
135 }
136 }
137 return true;
138 }
139
140 bool operator!=(const GrowableArrayView<E>& rhs) const {
141 return !(*this == rhs);
142 }
143
144 E* data() {
145 return _data;
146 }
147
148 const E* data() const {
149 return _data;
150 }
151
152 E& at(int i) {
153 assert(0 <= i && i < _len, "illegal index");
154 return _data[i];
155 }
156
157 E const& at(int i) const {
158 assert(0 <= i && i < _len, "illegal index");
159 return _data[i];
160 }
161
162 E* adr_at(int i) const {
163 assert(0 <= i && i < _len, "illegal index");
164 return &_data[i];
165 }
166
167 E first() const {
168 assert(_len > 0, "empty list");
169 return _data[0];
170 }
171
172 E top() const {
173 assert(_len > 0, "empty list");
174 return _data[_len-1];
175 }
176
177 E last() const {
178 return top();
179 }
180
181 GrowableArrayIterator<E> begin() const {
182 return GrowableArrayIterator<E>(this, 0);
183 }
184
185 GrowableArrayIterator<E> end() const {
186 return GrowableArrayIterator<E>(this, length());
187 }
188
189 E pop() {
190 assert(_len > 0, "empty list");
191 return _data[--_len];
192 }
193
194 void at_put(int i, const E& elem) {
195 assert(0 <= i && i < _len, "illegal index");
196 _data[i] = elem;
197 }
198
199 bool contains(const E& elem) const {
200 for (int i = 0; i < _len; i++) {
201 if (_data[i] == elem) return true;
202 }
203 return false;
204 }
205
206 int find(const E& elem) const {
207 for (int i = 0; i < _len; i++) {
208 if (_data[i] == elem) return i;
209 }
210 return -1;
211 }
212
213 int find_from_end(const E& elem) const {
214 for (int i = _len-1; i >= 0; i--) {
215 if (_data[i] == elem) return i;
216 }
217 return -1;
218 }
219
220 int find(void* token, bool f(void*, E)) const {
221 for (int i = 0; i < _len; i++) {
222 if (f(token, _data[i])) return i;
223 }
224 return -1;
225 }
226
227 int find_from_end(void* token, bool f(void*, E)) const {
228 // start at the end of the array
229 for (int i = _len-1; i >= 0; i--) {
230 if (f(token, _data[i])) return i;
231 }
232 return -1;
233 }
234
235 // Order preserving remove operations.
236
237 void remove(const E& elem) {
238 // Assuming that element does exist.
239 bool removed = remove_if_existing(elem);
240 if (removed) return;
241 ShouldNotReachHere();
242 }
243
244 bool remove_if_existing(const E& elem) {
245 // Returns TRUE if elem is removed.
246 for (int i = 0; i < _len; i++) {
247 if (_data[i] == elem) {
248 remove_at(i);
249 return true;
250 }
251 }
252 return false;
253 }
254
255 void remove_at(int index) {
256 assert(0 <= index && index < _len, "illegal index");
257 for (int j = index + 1; j < _len; j++) {
258 _data[j-1] = _data[j];
259 }
260 _len--;
261 }
262
263 // Remove all elements up to the index (exclusive). The order is preserved.
264 void remove_till(int idx) {
265 for (int i = 0, j = idx; j < length(); i++, j++) {
266 at_put(i, at(j));
267 }
268 trunc_to(length() - idx);
269 }
270
271 // The order is changed.
272 void delete_at(int index) {
273 assert(0 <= index && index < _len, "illegal index");
274 if (index < --_len) {
275 // Replace removed element with last one.
276 _data[index] = _data[_len];
277 }
278 }
279
280 void sort(int f(E*, E*)) {
281 qsort(_data, length(), sizeof(E), (_sort_Fn)f);
282 }
283 // sort by fixed-stride sub arrays:
284 void sort(int f(E*, E*), int stride) {
285 qsort(_data, length() / stride, sizeof(E) * stride, (_sort_Fn)f);
286 }
287
288 template <typename K, int compare(const K&, const E&)> int find_sorted(const K& key, bool& found) {
289 found = false;
290 int min = 0;
291 int max = length() - 1;
292
293 while (max >= min) {
294 int mid = (int)(((uint)max + min) / 2);
295 E value = at(mid);
296 int diff = compare(key, value);
297 if (diff > 0) {
298 min = mid + 1;
299 } else if (diff < 0) {
300 max = mid - 1;
301 } else {
302 found = true;
303 return mid;
304 }
305 }
306 return min;
307 }
308
309 template <typename K>
310 int find_sorted(CompareClosure<E>* cc, const K& key, bool& found) {
311 found = false;
312 int min = 0;
313 int max = length() - 1;
314
315 while (max >= min) {
316 int mid = (int)(((uint)max + min) / 2);
317 E value = at(mid);
318 int diff = cc->do_compare(key, value);
319 if (diff > 0) {
320 min = mid + 1;
321 } else if (diff < 0) {
322 max = mid - 1;
323 } else {
324 found = true;
325 return mid;
326 }
327 }
328 return min;
329 }
330
331 void truncate_to(int idx) {
332 for (int i = 0, j = idx; j < length(); i++, j++) {
333 at_put(i, at(j));
334 }
335 trunc_to(length() - idx);
336 }
337
338 void truncate_from(int idx) {
339 trunc_to(idx);
340 }
341
342 size_t data_size_in_bytes() const {
343 return _len * sizeof(E);
344 }
345
346 void print() const {
347 tty->print("Growable Array " INTPTR_FORMAT, p2i(this));
348 tty->print(": length %d (_max %d) { ", _len, _max);
349 for (int i = 0; i < _len; i++) {
350 tty->print(INTPTR_FORMAT " ", *(intptr_t*)&(_data[i]));
351 }
352 tty->print("}\n");
353 }
354 };
355
356 template<typename E>
357 const GrowableArrayView<E> GrowableArrayView<E>::EMPTY(nullptr, 0, 0);
358
359 // GrowableArrayWithAllocator extends the "view" with
360 // the capability to grow and deallocate the data array.
361 //
362 // The allocator responsibility is delegated to the sub-class.
363 //
364 // Derived: The sub-class responsible for allocation / deallocation
365 // - E* Derived::allocate() - member function responsible for allocation
366 // - void Derived::deallocate(E*) - member function responsible for deallocation
367 template <typename E, typename Derived>
368 class GrowableArrayWithAllocator : public GrowableArrayView<E> {
369 friend class VMStructs;
370
371 void grow(int j);
372
373 protected:
374 GrowableArrayWithAllocator(E* data, int initial_max) :
375 GrowableArrayView<E>(data, initial_max, 0) {
376 for (int i = 0; i < initial_max; i++) {
377 ::new ((void*)&data[i]) E();
378 }
379 }
380
381 GrowableArrayWithAllocator(E* data, int initial_max, int initial_len, const E& filler) :
382 GrowableArrayView<E>(data, initial_max, initial_len) {
383 int i = 0;
384 for (; i < initial_len; i++) {
385 ::new ((void*)&data[i]) E(filler);
386 }
387 for (; i < initial_max; i++) {
388 ::new ((void*)&data[i]) E();
389 }
390 }
391
392 ~GrowableArrayWithAllocator() {}
393
394 public:
395 int append(const E& elem) {
396 if (this->_len == this->_max) grow(this->_len);
397 int idx = this->_len++;
398 this->_data[idx] = elem;
399 return idx;
400 }
401
402 bool append_if_missing(const E& elem) {
403 // Returns TRUE if elem is added.
404 bool missed = !this->contains(elem);
405 if (missed) append(elem);
406 return missed;
407 }
408
409 void push(const E& elem) { append(elem); }
410
411 E at_grow(int i, const E& fill = E()) {
412 assert(0 <= i, "negative index");
413 if (i >= this->_len) {
414 if (i >= this->_max) grow(i);
415 for (int j = this->_len; j <= i; j++)
416 this->_data[j] = fill;
417 this->_len = i+1;
418 }
419 return this->_data[i];
420 }
421
422 void at_put_grow(int i, const E& elem, const E& fill = E()) {
423 assert(0 <= i, "negative index");
424 if (i >= this->_len) {
425 if (i >= this->_max) grow(i);
426 for (int j = this->_len; j < i; j++)
427 this->_data[j] = fill;
428 this->_len = i+1;
429 }
430 this->_data[i] = elem;
431 }
432
433 // inserts the given element before the element at index i
434 void insert_before(const int idx, const E& elem) {
435 assert(0 <= idx && idx <= this->_len, "illegal index");
436 if (this->_len == this->_max) grow(this->_len);
437 for (int j = this->_len - 1; j >= idx; j--) {
438 this->_data[j + 1] = this->_data[j];
439 }
440 this->_len++;
441 this->_data[idx] = elem;
442 }
443
444 void insert_before(const int idx, const GrowableArrayView<E>* array) {
445 assert(0 <= idx && idx <= this->_len, "illegal index");
446 int array_len = array->length();
447 int new_len = this->_len + array_len;
448 if (new_len >= this->_max) grow(new_len);
449
450 for (int j = this->_len - 1; j >= idx; j--) {
451 this->_data[j + array_len] = this->_data[j];
452 }
453
454 for (int j = 0; j < array_len; j++) {
455 this->_data[idx + j] = array->at(j);
456 }
457
458 this->_len += array_len;
459 }
460
461 void appendAll(const GrowableArrayView<E>* l) {
462 for (int i = 0; i < l->length(); i++) {
463 this->at_put_grow(this->_len, l->at(i), E());
464 }
465 }
466
467 // Binary search and insertion utility. Search array for element
468 // matching key according to the static compare function. Insert
469 // that element if not already in the list. Assumes the list is
470 // already sorted according to compare function.
471 template <int compare(const E&, const E&)> E insert_sorted(const E& key) {
472 bool found;
473 int location = GrowableArrayView<E>::template find_sorted<E, compare>(key, found);
474 if (!found) {
475 insert_before(location, key);
476 }
477 return this->at(location);
478 }
479
480 E insert_sorted(CompareClosure<E>* cc, const E& key) {
481 bool found;
482 int location = find_sorted(cc, key, found);
483 if (!found) {
484 insert_before(location, key);
485 }
486 return this->at(location);
487 }
488
489 void swap(GrowableArrayWithAllocator<E, Derived>* other) {
490 ::swap(this->_data, other->_data);
491 ::swap(this->_len, other->_len);
492 ::swap(this->_max, other->_max);
493 }
494
495 void clear_and_deallocate();
496 };
497
498 template <typename E, typename Derived>
499 void GrowableArrayWithAllocator<E, Derived>::grow(int j) {
500 int old_max = this->_max;
501 // grow the array by increasing _max to the first power of two larger than the size we need
502 this->_max = next_power_of_2((uint32_t)j);
503 // j < _max
504 E* newData = static_cast<Derived*>(this)->allocate();
505 int i = 0;
506 for ( ; i < this->_len; i++) ::new ((void*)&newData[i]) E(this->_data[i]);
507 for ( ; i < this->_max; i++) ::new ((void*)&newData[i]) E();
508 for (i = 0; i < old_max; i++) this->_data[i].~E();
509 if (this->_data != NULL) {
510 static_cast<Derived*>(this)->deallocate(this->_data);
511 }
512 this->_data = newData;
513 }
514
515 template <typename E, typename Derived>
516 void GrowableArrayWithAllocator<E, Derived>::clear_and_deallocate() {
517 if (this->_data != NULL) {
518 for (int i = 0; i < this->_max; i++) {
519 this->_data[i].~E();
520 }
521 static_cast<Derived*>(this)->deallocate(this->_data);
522 this->_data = NULL;
523 }
524 this->_len = 0;
525 this->_max = 0;
526 }
527
528 class GrowableArrayResourceAllocator {
529 public:
530 static void* allocate(int max, int element_size);
531 };
532
533 // Arena allocator
534 class GrowableArrayArenaAllocator {
535 public:
536 static void* allocate(int max, int element_size, Arena* arena);
537 };
538
539 // CHeap allocator
540 class GrowableArrayCHeapAllocator {
541 public:
542 static void* allocate(int max, int element_size, MEMFLAGS memflags);
543 static void deallocate(void* mem);
544 };
545
546 #ifdef ASSERT
547
548 // Checks resource allocation nesting
549 class GrowableArrayNestingCheck {
550 // resource area nesting at creation
551 int _nesting;
552
553 public:
554 GrowableArrayNestingCheck(bool on_stack);
555
556 void on_stack_alloc() const;
557 };
558
559 #endif // ASSERT
560
561 // Encodes where the backing array is allocated
562 // and performs necessary checks.
563 class GrowableArrayMetadata {
564 uintptr_t _bits;
565
566 // resource area nesting at creation
567 debug_only(GrowableArrayNestingCheck _nesting_check;)
568
569 uintptr_t bits(MEMFLAGS memflags) const {
570 if (memflags == mtNone) {
571 // Stack allocation
572 return 0;
573 }
574
575 // CHeap allocation
576 return (uintptr_t(memflags) << 1) | 1;
577 }
578
579 uintptr_t bits(Arena* arena) const {
580 return uintptr_t(arena);
581 }
582
583 public:
584 GrowableArrayMetadata(Arena* arena) :
585 _bits(bits(arena))
586 debug_only(COMMA _nesting_check(on_stack())) {
587 }
588
589 GrowableArrayMetadata(MEMFLAGS memflags) :
590 _bits(bits(memflags))
591 debug_only(COMMA _nesting_check(on_stack())) {
592 }
593
594 #ifdef ASSERT
595 GrowableArrayMetadata(const GrowableArrayMetadata& other) :
596 _bits(other._bits),
597 _nesting_check(other._nesting_check) {
598 assert(!on_C_heap(), "Copying of CHeap arrays not supported");
599 assert(!other.on_C_heap(), "Copying of CHeap arrays not supported");
600 }
601
602 GrowableArrayMetadata& operator=(const GrowableArrayMetadata& other) {
603 _bits = other._bits;
604 _nesting_check = other._nesting_check;
605 assert(!on_C_heap(), "Assignment of CHeap arrays not supported");
606 assert(!other.on_C_heap(), "Assignment of CHeap arrays not supported");
607 return *this;
608 }
609
610 void init_checks(const GrowableArrayBase* array) const;
611 void on_stack_alloc_check() const;
612 #endif // ASSERT
613
614 bool on_C_heap() const { return (_bits & 1) == 1; }
615 bool on_stack () const { return _bits == 0; }
616 bool on_arena () const { return (_bits & 1) == 0 && _bits != 0; }
617
618 Arena* arena() const { return (Arena*)_bits; }
619 MEMFLAGS memflags() const { return MEMFLAGS(_bits >> 1); }
620 };
621
622 // THE GrowableArray.
623 //
624 // Supports multiple allocation strategies:
625 // - Resource stack allocation: if memflags == mtNone
626 // - CHeap allocation: if memflags != mtNone
627 // - Arena allocation: if an arena is provided
628 //
629 // There are some drawbacks of using GrowableArray, that are removed in some
630 // of the other implementations of GrowableArrayWithAllocator sub-classes:
631 //
632 // Memory overhead: The multiple allocation strategies uses extra metadata
633 // embedded in the instance.
634 //
635 // Strict allocation locations: There are rules about where the GrowableArray
636 // instance is allocated, that depends on where the data array is allocated.
637 // See: init_checks.
638
639 template <typename E>
640 class GrowableArray : public GrowableArrayWithAllocator<E, GrowableArray<E> > {
641 friend class GrowableArrayWithAllocator<E, GrowableArray<E> >;
642 friend class GrowableArrayTest;
643
644 static E* allocate(int max) {
645 return (E*)GrowableArrayResourceAllocator::allocate(max, sizeof(E));
646 }
647
648 static E* allocate(int max, MEMFLAGS memflags) {
649 if (memflags != mtNone) {
650 return (E*)GrowableArrayCHeapAllocator::allocate(max, sizeof(E), memflags);
651 }
652
653 return (E*)GrowableArrayResourceAllocator::allocate(max, sizeof(E));
654 }
655
656 static E* allocate(int max, Arena* arena) {
657 return (E*)GrowableArrayArenaAllocator::allocate(max, sizeof(E), arena);
658 }
659
660 GrowableArrayMetadata _metadata;
661
662 void init_checks() const { debug_only(_metadata.init_checks(this);) }
663
664 // Where are we going to allocate memory?
665 bool on_C_heap() const { return _metadata.on_C_heap(); }
666 bool on_stack () const { return _metadata.on_stack(); }
667 bool on_arena () const { return _metadata.on_arena(); }
668
669 E* allocate() {
670 if (on_stack()) {
671 debug_only(_metadata.on_stack_alloc_check());
672 return allocate(this->_max);
673 }
674
675 if (on_C_heap()) {
676 return allocate(this->_max, _metadata.memflags());
677 }
678
679 assert(on_arena(), "Sanity");
680 return allocate(this->_max, _metadata.arena());
681 }
682
683 void deallocate(E* mem) {
684 if (on_C_heap()) {
685 GrowableArrayCHeapAllocator::deallocate(mem);
686 }
687 }
688
689 public:
690 GrowableArray(int initial_max = 2, MEMFLAGS memflags = mtNone) :
691 GrowableArrayWithAllocator<E, GrowableArray<E> >(
692 allocate(initial_max, memflags),
693 initial_max),
694 _metadata(memflags) {
695 init_checks();
696 }
697
698 GrowableArray(int initial_max, int initial_len, const E& filler, MEMFLAGS memflags = mtNone) :
699 GrowableArrayWithAllocator<E, GrowableArray<E> >(
700 allocate(initial_max, memflags),
701 initial_max, initial_len, filler),
702 _metadata(memflags) {
703 init_checks();
704 }
705
706 GrowableArray(Arena* arena, int initial_max, int initial_len, const E& filler) :
707 GrowableArrayWithAllocator<E, GrowableArray<E> >(
708 allocate(initial_max, arena),
709 initial_max, initial_len, filler),
710 _metadata(arena) {
711 init_checks();
712 }
713
714 ~GrowableArray() {
715 if (on_C_heap()) {
716 this->clear_and_deallocate();
717 }
718 }
719 };
720
721 // Leaner GrowableArray for CHeap backed data arrays, with compile-time decided MEMFLAGS.
722 template <typename E, MEMFLAGS F>
723 class GrowableArrayCHeap : public GrowableArrayWithAllocator<E, GrowableArrayCHeap<E, F> > {
724 friend class GrowableArrayWithAllocator<E, GrowableArrayCHeap<E, F> >;
725
726 STATIC_ASSERT(F != mtNone);
727
728 static E* allocate(int max, MEMFLAGS flags) {
729 if (max == 0) {
730 return NULL;
731 }
732
733 return (E*)GrowableArrayCHeapAllocator::allocate(max, sizeof(E), flags);
734 }
735
736 NONCOPYABLE(GrowableArrayCHeap);
737
738 E* allocate() {
739 return allocate(this->_max, F);
740 }
741
742 void deallocate(E* mem) {
743 GrowableArrayCHeapAllocator::deallocate(mem);
744 }
745
746 public:
747 GrowableArrayCHeap(int initial_max = 0) :
748 GrowableArrayWithAllocator<E, GrowableArrayCHeap<E, F> >(
749 allocate(initial_max, F),
750 initial_max) {}
751
752 GrowableArrayCHeap(int initial_max, int initial_len, const E& filler) :
753 GrowableArrayWithAllocator<E, GrowableArrayCHeap<E, F> >(
754 allocate(initial_max, F),
755 initial_max, initial_len, filler) {}
756
757 ~GrowableArrayCHeap() {
758 this->clear_and_deallocate();
759 }
760
761 void* operator new(size_t size) throw() {
762 return ResourceObj::operator new(size, ResourceObj::C_HEAP, F);
763 }
764
765 void* operator new(size_t size, const std::nothrow_t& nothrow_constant) throw() {
766 return ResourceObj::operator new(size, nothrow_constant, ResourceObj::C_HEAP, F);
767 }
768 };
769
770 // Custom STL-style iterator to iterate over GrowableArrays
771 // It is constructed by invoking GrowableArray::begin() and GrowableArray::end()
772 template <typename E>
773 class GrowableArrayIterator : public StackObj {
774 friend class GrowableArrayView<E>;
775 template <typename F, typename UnaryPredicate> friend class GrowableArrayFilterIterator;
776
777 private:
778 const GrowableArrayView<E>* _array; // GrowableArray we iterate over
779 int _position; // The current position in the GrowableArray
780
781 // Private constructor used in GrowableArray::begin() and GrowableArray::end()
782 GrowableArrayIterator(const GrowableArrayView<E>* array, int position) : _array(array), _position(position) {
783 assert(0 <= position && position <= _array->length(), "illegal position");
784 }
785
786 public:
787 GrowableArrayIterator() : _array(NULL), _position(0) { }
788 GrowableArrayIterator<E>& operator++() { ++_position; return *this; }
789 E operator*() { return _array->at(_position); }
790
791 bool operator==(const GrowableArrayIterator<E>& rhs) {
792 assert(_array == rhs._array, "iterator belongs to different array");
793 return _position == rhs._position;
794 }
795
796 bool operator!=(const GrowableArrayIterator<E>& rhs) {
797 assert(_array == rhs._array, "iterator belongs to different array");
798 return _position != rhs._position;
799 }
800 };
801
802 // Custom STL-style iterator to iterate over elements of a GrowableArray that satisfy a given predicate
803 template <typename E, class UnaryPredicate>
804 class GrowableArrayFilterIterator : public StackObj {
805 friend class GrowableArrayView<E>;
806
807 private:
808 const GrowableArrayView<E>* _array; // GrowableArray we iterate over
809 int _position; // Current position in the GrowableArray
810 UnaryPredicate _predicate; // Unary predicate the elements of the GrowableArray should satisfy
811
812 public:
813 GrowableArrayFilterIterator(const GrowableArrayIterator<E>& begin, UnaryPredicate filter_predicate) :
814 _array(begin._array), _position(begin._position), _predicate(filter_predicate) {
815 // Advance to first element satisfying the predicate
816 while(_position != _array->length() && !_predicate(_array->at(_position))) {
817 ++_position;
818 }
819 }
820
821 GrowableArrayFilterIterator<E, UnaryPredicate>& operator++() {
822 do {
823 // Advance to next element satisfying the predicate
824 ++_position;
825 } while(_position != _array->length() && !_predicate(_array->at(_position)));
826 return *this;
827 }
828
829 E operator*() { return _array->at(_position); }
830
831 bool operator==(const GrowableArrayIterator<E>& rhs) {
832 assert(_array == rhs._array, "iterator belongs to different array");
833 return _position == rhs._position;
834 }
835
836 bool operator!=(const GrowableArrayIterator<E>& rhs) {
837 assert(_array == rhs._array, "iterator belongs to different array");
838 return _position != rhs._position;
839 }
840
841 bool operator==(const GrowableArrayFilterIterator<E, UnaryPredicate>& rhs) {
842 assert(_array == rhs._array, "iterator belongs to different array");
843 return _position == rhs._position;
844 }
845
846 bool operator!=(const GrowableArrayFilterIterator<E, UnaryPredicate>& rhs) {
847 assert(_array == rhs._array, "iterator belongs to different array");
848 return _position != rhs._position;
849 }
850 };
851
852 // Arrays for basic types
853 typedef GrowableArray<int> intArray;
854 typedef GrowableArray<int> intStack;
855 typedef GrowableArray<bool> boolArray;
856
857 #endif // SHARE_UTILITIES_GROWABLEARRAY_HPP