This repository has been archived by the owner on Apr 10, 2024. It is now read-only.
/
nsTArray.h
1450 lines (1260 loc) · 48.6 KB
/
nsTArray.h
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef nsTArray_h__
#define nsTArray_h__
#include "mozilla/Assertions.h"
#include "mozilla/Util.h"
#include <string.h>
#include "nsAlgorithm.h"
#include "nscore.h"
#include "nsQuickSort.h"
#include "nsDebug.h"
#include "nsTraceRefcnt.h"
#include NEW_H
//
// NB: nsTArray assumes that your "T" can be memmove()d. This is in
// contrast to STL containers, which follow C++
// construction/destruction rules.
//
// Don't use nsTArray if your "T" can't be memmove()d correctly.
//
//
// nsTArray*Allocators must all use the same |free()|, to allow
// swapping between fallible and infallible variants. (NS_Free() and
// moz_free() end up calling the same underlying free()).
//
#if defined(MOZALLOC_HAVE_XMALLOC)
#include "mozilla/mozalloc_abort.h"
struct nsTArrayFallibleAllocator
{
static void* Malloc(size_t size) {
return moz_malloc(size);
}
static void* Realloc(void* ptr, size_t size) {
return moz_realloc(ptr, size);
}
static void Free(void* ptr) {
moz_free(ptr);
}
static void SizeTooBig() {
}
};
struct nsTArrayInfallibleAllocator
{
static void* Malloc(size_t size) {
return moz_xmalloc(size);
}
static void* Realloc(void* ptr, size_t size) {
return moz_xrealloc(ptr, size);
}
static void Free(void* ptr) {
moz_free(ptr);
}
static void SizeTooBig() {
mozalloc_abort("Trying to allocate an infallible array that's too big");
}
};
#else
#include <stdlib.h>
struct nsTArrayFallibleAllocator
{
static void* Malloc(size_t size) {
return malloc(size);
}
static void* Realloc(void* ptr, size_t size) {
return realloc(ptr, size);
}
static void Free(void* ptr) {
free(ptr);
}
static void SizeTooBig() {
}
};
#endif
#if defined(MOZALLOC_HAVE_XMALLOC)
struct nsTArrayDefaultAllocator : public nsTArrayInfallibleAllocator { };
#else
struct nsTArrayDefaultAllocator : public nsTArrayFallibleAllocator { };
#endif
// nsTArray_base stores elements into the space allocated beyond
// sizeof(*this). This is done to minimize the size of the nsTArray
// object when it is empty.
struct NS_COM_GLUE nsTArrayHeader
{
static nsTArrayHeader sEmptyHdr;
uint32_t mLength;
uint32_t mCapacity : 31;
uint32_t mIsAutoArray : 1;
};
// This class provides a SafeElementAt method to nsTArray<T*> which does
// not take a second default value parameter.
template <class E, class Derived>
struct nsTArray_SafeElementAtHelper
{
typedef E* elem_type;
typedef uint32_t index_type;
// No implementation is provided for these two methods, and that is on
// purpose, since we don't support these functions on non-pointer type
// instantiations.
elem_type& SafeElementAt(index_type i);
const elem_type& SafeElementAt(index_type i) const;
};
template <class E, class Derived>
struct nsTArray_SafeElementAtHelper<E*, Derived>
{
typedef E* elem_type;
typedef uint32_t index_type;
elem_type SafeElementAt(index_type i) {
return static_cast<Derived*> (this)->SafeElementAt(i, nullptr);
}
const elem_type SafeElementAt(index_type i) const {
return static_cast<const Derived*> (this)->SafeElementAt(i, nullptr);
}
};
// E is the base type that the smart pointer is templated over; the
// smart pointer can act as E*.
template <class E, class Derived>
struct nsTArray_SafeElementAtSmartPtrHelper
{
typedef E* elem_type;
typedef uint32_t index_type;
elem_type SafeElementAt(index_type i) {
return static_cast<Derived*> (this)->SafeElementAt(i, nullptr);
}
const elem_type SafeElementAt(index_type i) const {
return static_cast<const Derived*> (this)->SafeElementAt(i, nullptr);
}
};
template <class T> class nsCOMPtr;
template <class E, class Derived>
struct nsTArray_SafeElementAtHelper<nsCOMPtr<E>, Derived> :
public nsTArray_SafeElementAtSmartPtrHelper<E, Derived>
{
};
template <class T> class nsRefPtr;
template <class E, class Derived>
struct nsTArray_SafeElementAtHelper<nsRefPtr<E>, Derived> :
public nsTArray_SafeElementAtSmartPtrHelper<E, Derived>
{
};
//
// This class serves as a base class for nsTArray. It shouldn't be used
// directly. It holds common implementation code that does not depend on the
// element type of the nsTArray.
//
template<class Alloc>
class nsTArray_base
{
// Allow swapping elements with |nsTArray_base|s created using a
// different allocator. This is kosher because all allocators use
// the same free().
template<class Allocator>
friend class nsTArray_base;
protected:
typedef nsTArrayHeader Header;
public:
typedef uint32_t size_type;
typedef uint32_t index_type;
// @return The number of elements in the array.
size_type Length() const {
return mHdr->mLength;
}
// @return True if the array is empty or false otherwise.
bool IsEmpty() const {
return Length() == 0;
}
// @return The number of elements that can fit in the array without forcing
// the array to be re-allocated. The length of an array is always less
// than or equal to its capacity.
size_type Capacity() const {
return mHdr->mCapacity;
}
#ifdef DEBUG
void* DebugGetHeader() const {
return mHdr;
}
#endif
protected:
nsTArray_base();
~nsTArray_base();
// Resize the storage if necessary to achieve the requested capacity.
// @param capacity The requested number of array elements.
// @param elemSize The size of an array element.
// @return False if insufficient memory is available; true otherwise.
bool EnsureCapacity(size_type capacity, size_type elemSize);
// Resize the storage to the minimum required amount.
// @param elemSize The size of an array element.
// @param elemAlign The alignment in bytes of an array element.
void ShrinkCapacity(size_type elemSize, size_t elemAlign);
// This method may be called to resize a "gap" in the array by shifting
// elements around. It updates mLength appropriately. If the resulting
// array has zero elements, then the array's memory is free'd.
// @param start The starting index of the gap.
// @param oldLen The current length of the gap.
// @param newLen The desired length of the gap.
// @param elemSize The size of an array element.
// @param elemAlign The alignment in bytes of an array element.
void ShiftData(index_type start, size_type oldLen, size_type newLen,
size_type elemSize, size_t elemAlign);
// This method increments the length member of the array's header.
// Note that mHdr may actually be sEmptyHdr in the case where a
// zero-length array is inserted into our array. But then n should
// always be 0.
void IncrementLength(uint32_t n) {
MOZ_ASSERT(mHdr != EmptyHdr() || n == 0, "bad data pointer");
mHdr->mLength += n;
}
// This method inserts blank slots into the array.
// @param index the place to insert the new elements. This must be no
// greater than the current length of the array.
// @param count the number of slots to insert
// @param elementSize the size of an array element.
// @param elemAlign the alignment in bytes of an array element.
bool InsertSlotsAt(index_type index, size_type count,
size_type elementSize, size_t elemAlign);
protected:
template<class Allocator>
bool SwapArrayElements(nsTArray_base<Allocator>& other,
size_type elemSize,
size_t elemAlign);
// This is an RAII class used in SwapArrayElements.
class IsAutoArrayRestorer {
public:
IsAutoArrayRestorer(nsTArray_base<Alloc> &array, size_t elemAlign);
~IsAutoArrayRestorer();
private:
nsTArray_base<Alloc> &mArray;
size_t mElemAlign;
bool mIsAuto;
};
// Helper function for SwapArrayElements. Ensures that if the array
// is an nsAutoTArray that it doesn't use the built-in buffer.
bool EnsureNotUsingAutoArrayBuffer(size_type elemSize);
// Returns true if this nsTArray is an nsAutoTArray with a built-in buffer.
bool IsAutoArray() const {
return mHdr->mIsAutoArray;
}
// Returns a Header for the built-in buffer of this nsAutoTArray.
Header* GetAutoArrayBuffer(size_t elemAlign) {
MOZ_ASSERT(IsAutoArray(), "Should be an auto array to call this");
return GetAutoArrayBufferUnsafe(elemAlign);
}
const Header* GetAutoArrayBuffer(size_t elemAlign) const {
MOZ_ASSERT(IsAutoArray(), "Should be an auto array to call this");
return GetAutoArrayBufferUnsafe(elemAlign);
}
// Returns a Header for the built-in buffer of this nsAutoTArray, but doesn't
// assert that we are an nsAutoTArray.
Header* GetAutoArrayBufferUnsafe(size_t elemAlign) {
return const_cast<Header*>(static_cast<const nsTArray_base<Alloc>*>(this)->
GetAutoArrayBufferUnsafe(elemAlign));
}
const Header* GetAutoArrayBufferUnsafe(size_t elemAlign) const;
// Returns true if this is an nsAutoTArray and it currently uses the
// built-in buffer to store its elements.
bool UsesAutoArrayBuffer() const;
// The array's elements (prefixed with a Header). This pointer is never
// null. If the array is empty, then this will point to sEmptyHdr.
Header *mHdr;
Header* Hdr() const {
return mHdr;
}
Header** PtrToHdr() {
return &mHdr;
}
static Header* EmptyHdr() {
return &Header::sEmptyHdr;
}
};
//
// This class defines convenience functions for element specific operations.
// Specialize this template if necessary.
//
template<class E>
class nsTArrayElementTraits
{
public:
// Invoke the default constructor in place.
static inline void Construct(E *e) {
// Do NOT call "E()"! That triggers C++ "default initialization"
// which zeroes out POD ("plain old data") types such as regular
// ints. We don't want that because it can be a performance issue
// and people don't expect it; nsTArray should work like a regular
// C/C++ array in this respect.
new (static_cast<void *>(e)) E;
}
// Invoke the copy-constructor in place.
template<class A>
static inline void Construct(E *e, const A &arg) {
new (static_cast<void *>(e)) E(arg);
}
// Invoke the destructor in place.
static inline void Destruct(E *e) {
e->~E();
}
};
// The default comparator used by nsTArray
template<class A, class B>
class nsDefaultComparator
{
public:
bool Equals(const A& a, const B& b) const {
return a == b;
}
bool LessThan(const A& a, const B& b) const {
return a < b;
}
};
//
// The templatized array class that dynamically resizes its storage as
// elements are added. This class is designed to behave a bit like
// std::vector, though note that unlike std::vector, nsTArray doesn't
// follow C++ construction/destruction rules.
//
// The template parameter specifies the type of the elements (elem_type), and
// has the following requirements:
//
// elem_type MUST define a copy-constructor.
// elem_type MAY define operator< for sorting.
// elem_type MAY define operator== for searching.
//
// For methods taking a Comparator instance, the Comparator must be a class
// defining the following methods:
//
// class Comparator {
// public:
// /** @return True if the elements are equals; false otherwise. */
// bool Equals(const elem_type& a, const Item& b) const;
//
// /** @return True if (a < b); false otherwise. */
// bool LessThan(const elem_type& a, const Item& b) const;
// };
//
// The Equals method is used for searching, and the LessThan method is used
// for sorting. The |Item| type above can be arbitrary, but must match the
// Item type passed to the sort or search function.
//
// The Alloc template parameter can be used to choose between
// "fallible" and "infallible" nsTArray (if available), defaulting to
// fallible. If the *fallible* allocator is used, the return value of
// methods that might allocate needs to be checked; Append() is
// one such method. These return values don't need to be checked if
// the *in*fallible allocator is chosen. When in doubt, choose the
// infallible allocator.
//
template<class E, class Alloc=nsTArrayDefaultAllocator>
class nsTArray : public nsTArray_base<Alloc>,
public nsTArray_SafeElementAtHelper<E, nsTArray<E, Alloc> >
{
public:
typedef nsTArray_base<Alloc> base_type;
typedef typename base_type::size_type size_type;
typedef typename base_type::index_type index_type;
typedef E elem_type;
typedef nsTArray<E, Alloc> self_type;
typedef nsTArrayElementTraits<E> elem_traits;
typedef nsTArray_SafeElementAtHelper<E, self_type> safeelementat_helper_type;
using safeelementat_helper_type::SafeElementAt;
using base_type::EmptyHdr;
// A special value that is used to indicate an invalid or unknown index
// into the array.
enum {
NoIndex = index_type(-1)
};
using base_type::Length;
//
// Finalization method
//
~nsTArray() { Clear(); }
//
// Initialization methods
//
nsTArray() {}
// Initialize this array and pre-allocate some number of elements.
explicit nsTArray(size_type capacity) {
SetCapacity(capacity);
}
// The array's copy-constructor performs a 'deep' copy of the given array.
// @param other The array object to copy.
nsTArray(const self_type& other) {
AppendElements(other);
}
template<typename Allocator>
nsTArray(const nsTArray<E, Allocator>& other) {
AppendElements(other);
}
// The array's assignment operator performs a 'deep' copy of the given
// array. It is optimized to reuse existing storage if possible.
// @param other The array object to copy.
nsTArray& operator=(const self_type& other) {
ReplaceElementsAt(0, Length(), other.Elements(), other.Length());
return *this;
}
// Return true if this array has the same length and the same
// elements as |other|.
bool operator==(const self_type& other) const {
size_type len = Length();
if (len != other.Length())
return false;
// XXX std::equal would be as fast or faster here
for (index_type i = 0; i < len; ++i)
if (!(operator[](i) == other[i]))
return false;
return true;
}
// Return true if this array does not have the same length and the same
// elements as |other|.
bool operator!=(const self_type& other) const {
return !operator==(other);
}
template<typename Allocator>
nsTArray& operator=(const nsTArray<E, Allocator>& other) {
ReplaceElementsAt(0, Length(), other.Elements(), other.Length());
return *this;
}
// @return The amount of memory used by this nsTArray, excluding
// sizeof(*this).
size_t SizeOfExcludingThis(nsMallocSizeOfFun mallocSizeOf) const {
if (this->UsesAutoArrayBuffer() || Hdr() == EmptyHdr())
return 0;
return mallocSizeOf(this->Hdr());
}
// @return The amount of memory used by this nsTArray, including
// sizeof(*this).
size_t SizeOfIncludingThis(nsMallocSizeOfFun mallocSizeOf) const {
return mallocSizeOf(this) + SizeOfExcludingThis(mallocSizeOf);
}
//
// Accessor methods
//
// This method provides direct access to the array elements.
// @return A pointer to the first element of the array. If the array is
// empty, then this pointer must not be dereferenced.
elem_type* Elements() {
return reinterpret_cast<elem_type *>(Hdr() + 1);
}
// This method provides direct, readonly access to the array elements.
// @return A pointer to the first element of the array. If the array is
// empty, then this pointer must not be dereferenced.
const elem_type* Elements() const {
return reinterpret_cast<const elem_type *>(Hdr() + 1);
}
// This method provides direct access to the i'th element of the array.
// The given index must be within the array bounds.
// @param i The index of an element in the array.
// @return A reference to the i'th element of the array.
elem_type& ElementAt(index_type i) {
MOZ_ASSERT(i < Length(), "invalid array index");
return Elements()[i];
}
// This method provides direct, readonly access to the i'th element of the
// array. The given index must be within the array bounds.
// @param i The index of an element in the array.
// @return A const reference to the i'th element of the array.
const elem_type& ElementAt(index_type i) const {
MOZ_ASSERT(i < Length(), "invalid array index");
return Elements()[i];
}
// This method provides direct access to the i'th element of the array in
// a bounds safe manner. If the requested index is out of bounds the
// provided default value is returned.
// @param i The index of an element in the array.
// @param def The value to return if the index is out of bounds.
elem_type& SafeElementAt(index_type i, elem_type& def) {
return i < Length() ? Elements()[i] : def;
}
// This method provides direct access to the i'th element of the array in
// a bounds safe manner. If the requested index is out of bounds the
// provided default value is returned.
// @param i The index of an element in the array.
// @param def The value to return if the index is out of bounds.
const elem_type& SafeElementAt(index_type i, const elem_type& def) const {
return i < Length() ? Elements()[i] : def;
}
// Shorthand for ElementAt(i)
elem_type& operator[](index_type i) {
return ElementAt(i);
}
// Shorthand for ElementAt(i)
const elem_type& operator[](index_type i) const {
return ElementAt(i);
}
// Shorthand for ElementAt(length - 1)
elem_type& LastElement() {
return ElementAt(Length() - 1);
}
// Shorthand for ElementAt(length - 1)
const elem_type& LastElement() const {
return ElementAt(Length() - 1);
}
// Shorthand for SafeElementAt(length - 1, def)
elem_type& SafeLastElement(elem_type& def) {
return SafeElementAt(Length() - 1, def);
}
// Shorthand for SafeElementAt(length - 1, def)
const elem_type& SafeLastElement(const elem_type& def) const {
return SafeElementAt(Length() - 1, def);
}
//
// Search methods
//
// This method searches for the first element in this array that is equal
// to the given element.
// @param item The item to search for.
// @param comp The Comparator used to determine element equality.
// @return true if the element was found.
template<class Item, class Comparator>
bool Contains(const Item& item, const Comparator& comp) const {
return IndexOf(item, 0, comp) != NoIndex;
}
// This method searches for the first element in this array that is equal
// to the given element. This method assumes that 'operator==' is defined
// for elem_type.
// @param item The item to search for.
// @return true if the element was found.
template<class Item>
bool Contains(const Item& item) const {
return IndexOf(item) != NoIndex;
}
// This method searches for the offset of the first element in this
// array that is equal to the given element.
// @param item The item to search for.
// @param start The index to start from.
// @param comp The Comparator used to determine element equality.
// @return The index of the found element or NoIndex if not found.
template<class Item, class Comparator>
index_type IndexOf(const Item& item, index_type start,
const Comparator& comp) const {
const elem_type* iter = Elements() + start, *end = Elements() + Length();
for (; iter != end; ++iter) {
if (comp.Equals(*iter, item))
return index_type(iter - Elements());
}
return NoIndex;
}
// This method searches for the offset of the first element in this
// array that is equal to the given element. This method assumes
// that 'operator==' is defined for elem_type.
// @param item The item to search for.
// @param start The index to start from.
// @return The index of the found element or NoIndex if not found.
template<class Item>
index_type IndexOf(const Item& item, index_type start = 0) const {
return IndexOf(item, start, nsDefaultComparator<elem_type, Item>());
}
// This method searches for the offset of the last element in this
// array that is equal to the given element.
// @param item The item to search for.
// @param start The index to start from. If greater than or equal to the
// length of the array, then the entire array is searched.
// @param comp The Comparator used to determine element equality.
// @return The index of the found element or NoIndex if not found.
template<class Item, class Comparator>
index_type LastIndexOf(const Item& item, index_type start,
const Comparator& comp) const {
if (start >= Length())
start = Length() - 1;
const elem_type* end = Elements() - 1, *iter = end + start + 1;
for (; iter != end; --iter) {
if (comp.Equals(*iter, item))
return index_type(iter - Elements());
}
return NoIndex;
}
// This method searches for the offset of the last element in this
// array that is equal to the given element. This method assumes
// that 'operator==' is defined for elem_type.
// @param item The item to search for.
// @param start The index to start from. If greater than or equal to the
// length of the array, then the entire array is searched.
// @return The index of the found element or NoIndex if not found.
template<class Item>
index_type LastIndexOf(const Item& item,
index_type start = NoIndex) const {
return LastIndexOf(item, start, nsDefaultComparator<elem_type, Item>());
}
// This method searches for the offset for the element in this array
// that is equal to the given element. The array is assumed to be sorted.
// @param item The item to search for.
// @param comp The Comparator used.
// @return The index of the found element or NoIndex if not found.
template<class Item, class Comparator>
index_type BinaryIndexOf(const Item& item, const Comparator& comp) const {
index_type low = 0, high = Length();
while (high > low) {
index_type mid = (high + low) >> 1;
if (comp.Equals(ElementAt(mid), item))
return mid;
if (comp.LessThan(ElementAt(mid), item))
low = mid + 1;
else
high = mid;
}
return NoIndex;
}
// This method searches for the offset for the element in this array
// that is equal to the given element. The array is assumed to be sorted.
// This method assumes that 'operator==' and 'operator<' are defined.
// @param item The item to search for.
// @return The index of the found element or NoIndex if not found.
template<class Item>
index_type BinaryIndexOf(const Item& item) const {
return BinaryIndexOf(item, nsDefaultComparator<elem_type, Item>());
}
//
// Mutation methods
//
// This method replaces a range of elements in this array.
// @param start The starting index of the elements to replace.
// @param count The number of elements to replace. This may be zero to
// insert elements without removing any existing elements.
// @param array The values to copy into this array. Must be non-null,
// and these elements must not already exist in the array
// being modified.
// @param arrayLen The number of values to copy into this array.
// @return A pointer to the new elements in the array, or null if
// the operation failed due to insufficient memory.
template<class Item>
elem_type *ReplaceElementsAt(index_type start, size_type count,
const Item* array, size_type arrayLen) {
// Adjust memory allocation up-front to catch errors.
if (!this->EnsureCapacity(Length() + arrayLen - count, sizeof(elem_type)))
return nullptr;
DestructRange(start, count);
this->ShiftData(start, count, arrayLen, sizeof(elem_type), MOZ_ALIGNOF(elem_type));
AssignRange(start, arrayLen, array);
return Elements() + start;
}
// A variation on the ReplaceElementsAt method defined above.
template<class Item>
elem_type *ReplaceElementsAt(index_type start, size_type count,
const nsTArray<Item>& array) {
return ReplaceElementsAt(start, count, array.Elements(), array.Length());
}
// A variation on the ReplaceElementsAt method defined above.
template<class Item>
elem_type *ReplaceElementsAt(index_type start, size_type count,
const Item& item) {
return ReplaceElementsAt(start, count, &item, 1);
}
// A variation on the ReplaceElementsAt method defined above.
template<class Item>
elem_type *ReplaceElementAt(index_type index, const Item& item) {
return ReplaceElementsAt(index, 1, &item, 1);
}
// A variation on the ReplaceElementsAt method defined above.
template<class Item>
elem_type *InsertElementsAt(index_type index, const Item* array,
size_type arrayLen) {
return ReplaceElementsAt(index, 0, array, arrayLen);
}
// A variation on the ReplaceElementsAt method defined above.
template<class Item>
elem_type *InsertElementsAt(index_type index, const nsTArray<Item>& array) {
return ReplaceElementsAt(index, 0, array.Elements(), array.Length());
}
// A variation on the ReplaceElementsAt method defined above.
template<class Item>
elem_type *InsertElementAt(index_type index, const Item& item) {
return ReplaceElementsAt(index, 0, &item, 1);
}
// Insert a new element without copy-constructing. This is useful to avoid
// temporaries.
// @return A pointer to the newly inserted element, or null on OOM.
elem_type* InsertElementAt(index_type index) {
if (!this->EnsureCapacity(Length() + 1, sizeof(elem_type)))
return nullptr;
this->ShiftData(index, 0, 1, sizeof(elem_type), MOZ_ALIGNOF(elem_type));
elem_type *elem = Elements() + index;
elem_traits::Construct(elem);
return elem;
}
// This method searches for the least index of the greatest
// element less than or equal to |item|. If |item| is inserted at
// this index, the array will remain sorted. True is returned iff
// this index is also equal to |item|. In this case, the returned
// index may point to the start of multiple copies of |item|.
// @param item The item to search for.
// @param comp The Comparator used.
// @outparam idx The index of greatest element <= to |item|
// @return True iff |item == array[*idx]|.
// @precondition The array is sorted
template<class Item, class Comparator>
bool
GreatestIndexLtEq(const Item& item,
const Comparator& comp,
index_type* idx) const {
// Nb: we could replace all the uses of "BinaryIndexOf" with this
// function, but BinaryIndexOf will be oh-so-slightly faster so
// it's not strictly desired to do.
// invariant: low <= [idx] < high
index_type low = 0, high = Length();
while (high > low) {
index_type mid = (high + low) >> 1;
if (comp.Equals(ElementAt(mid), item)) {
// we might have the array [..., 2, 4, 4, 4, 4, 4, 5, ...]
// and be searching for "4". it's arbitrary where mid ends
// up here, so we back it up to the first instance to maintain
// the "least index ..." we promised above.
do {
--mid;
} while (NoIndex != mid && comp.Equals(ElementAt(mid), item));
*idx = ++mid;
return true;
}
if (comp.LessThan(ElementAt(mid), item))
// invariant: low <= idx < high
low = mid + 1;
else
// invariant: low <= idx < high
high = mid;
}
// low <= idx < high, so insert at high ("shifting" high up by
// 1) to maintain invariant.
// (or insert at low, since low==high; just a matter of taste here.)
*idx = high;
return false;
}
// A variation on the GreatestIndexLtEq method defined above.
template<class Item, class Comparator>
bool
GreatestIndexLtEq(const Item& item,
index_type& idx,
const Comparator& comp) const {
return GreatestIndexLtEq(item, comp, &idx);
}
// A variation on the GreatestIndexLtEq method defined above.
template<class Item>
bool
GreatestIndexLtEq(const Item& item,
index_type& idx) const {
return GreatestIndexLtEq(item, nsDefaultComparator<elem_type, Item>(), &idx);
}
// Inserts |item| at such an index to guarantee that if the array
// was previously sorted, it will remain sorted after this
// insertion.
template<class Item, class Comparator>
elem_type *InsertElementSorted(const Item& item, const Comparator& comp) {
index_type index;
GreatestIndexLtEq(item, comp, &index);
return InsertElementAt(index, item);
}
// A variation on the InsertElementSorted method defined above.
template<class Item>
elem_type *InsertElementSorted(const Item& item) {
return InsertElementSorted(item, nsDefaultComparator<elem_type, Item>());
}
// This method appends elements to the end of this array.
// @param array The elements to append to this array.
// @param arrayLen The number of elements to append to this array.
// @return A pointer to the new elements in the array, or null if
// the operation failed due to insufficient memory.
template<class Item>
elem_type *AppendElements(const Item* array, size_type arrayLen) {
if (!this->EnsureCapacity(Length() + arrayLen, sizeof(elem_type)))
return nullptr;
index_type len = Length();
AssignRange(len, arrayLen, array);
this->IncrementLength(arrayLen);
return Elements() + len;
}
// A variation on the AppendElements method defined above.
template<class Item, class Allocator>
elem_type *AppendElements(const nsTArray<Item, Allocator>& array) {
return AppendElements(array.Elements(), array.Length());
}
// A variation on the AppendElements method defined above.
template<class Item>
elem_type *AppendElement(const Item& item) {
return AppendElements(&item, 1);
}
// Append new elements without copy-constructing. This is useful to avoid
// temporaries.
// @return A pointer to the newly appended elements, or null on OOM.
elem_type *AppendElements(size_type count) {
if (!this->EnsureCapacity(Length() + count, sizeof(elem_type)))
return nullptr;
elem_type *elems = Elements() + Length();
size_type i;
for (i = 0; i < count; ++i) {
elem_traits::Construct(elems + i);
}
this->IncrementLength(count);
return elems;
}
// Append a new element without copy-constructing. This is useful to avoid
// temporaries.
// @return A pointer to the newly appended element, or null on OOM.
elem_type *AppendElement() {
return AppendElements(1);
}
// Move all elements from another array to the end of this array without
// calling copy constructors or destructors.
// @return A pointer to the newly appended elements, or null on OOM.
template<class Item, class Allocator>
elem_type *MoveElementsFrom(nsTArray<Item, Allocator>& array) {
MOZ_ASSERT(&array != this, "argument must be different array");
index_type len = Length();
index_type otherLen = array.Length();
if (!this->EnsureCapacity(len + otherLen, sizeof(elem_type)))
return nullptr;
memcpy(Elements() + len, array.Elements(), otherLen * sizeof(elem_type));
this->IncrementLength(otherLen);
array.ShiftData(0, otherLen, 0, sizeof(elem_type), MOZ_ALIGNOF(elem_type));
return Elements() + len;
}
// This method removes a range of elements from this array.
// @param start The starting index of the elements to remove.
// @param count The number of elements to remove.
void RemoveElementsAt(index_type start, size_type count) {
MOZ_ASSERT(count == 0 || start < Length(), "Invalid start index");
MOZ_ASSERT(start + count <= Length(), "Invalid length");
// Check that the previous assert didn't overflow
MOZ_ASSERT(start <= start + count, "Start index plus length overflows");
DestructRange(start, count);
this->ShiftData(start, count, 0, sizeof(elem_type), MOZ_ALIGNOF(elem_type));
}
// A variation on the RemoveElementsAt method defined above.
void RemoveElementAt(index_type index) {
RemoveElementsAt(index, 1);
}
// A variation on the RemoveElementsAt method defined above.
void Clear() {
RemoveElementsAt(0, Length());
}
// This helper function combines IndexOf with RemoveElementAt to "search
// and destroy" the first element that is equal to the given element.
// @param item The item to search for.
// @param comp The Comparator used to determine element equality.
// @return true if the element was found
template<class Item, class Comparator>
bool RemoveElement(const Item& item, const Comparator& comp) {
index_type i = IndexOf(item, 0, comp);
if (i == NoIndex)
return false;
RemoveElementAt(i);
return true;
}
// A variation on the RemoveElement method defined above that assumes
// that 'operator==' is defined for elem_type.
template<class Item>
bool RemoveElement(const Item& item) {
return RemoveElement(item, nsDefaultComparator<elem_type, Item>());
}
// This helper function combines GreatestIndexLtEq with
// RemoveElementAt to "search and destroy" the first element that
// is equal to the given element.
// @param item The item to search for.
// @param comp The Comparator used to determine element equality.
// @return true if the element was found
template<class Item, class Comparator>
bool RemoveElementSorted(const Item& item, const Comparator& comp) {
index_type index;
bool found = GreatestIndexLtEq(item, comp, &index);
if (found)
RemoveElementAt(index);
return found;
}
// A variation on the RemoveElementSorted method defined above.
template<class Item>
bool RemoveElementSorted(const Item& item) {
return RemoveElementSorted(item, nsDefaultComparator<elem_type, Item>());
}