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
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
|
/****************************************************************************
**
** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:FDL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the Technology Preview License Agreement accompanying
** this package.
**
** GNU Free Documentation License
** Alternatively, this file may be used under the terms of the GNU Free
** Documentation License version 1.3 as published by the Free Software
** Foundation and appearing in the file included in the packaging of this
** file.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/
/*!
\class Q3PtrList
\brief The Q3PtrList class is a template class that provides a list.
\compat
Q3ValueList is an STL-compatible alternative to this class.
Define a template instance Q3PtrList\<X\> to create a list that
operates on pointers to X (X*).
The list class is indexable and has a \link at() current
index\endlink and a \link current() current item\endlink. The
first item corresponds to index position 0. The current index is
-1 if the current item is 0.
Items are inserted with prepend(), insert() or append(). Items are
removed with remove(), removeRef(), removeFirst() and
removeLast(). You can search for an item using find(), findNext(),
findRef() or findNextRef(). The list can be sorted with sort().
You can count the number of occurrences of an item with contains()
or containsRef(). You can get a pointer to the current item with
current(), to an item at a particular index position in the list
with at() or to the first or last item with getFirst() and
getLast(). You can also iterate over the list with first(),
last(), next() and prev() (which all update current()). The list's
deletion property is set with setAutoDelete().
\target example
Example:
\snippet doc/src/snippets/code/doc_src_q3ptrlist.cpp 0
The output is
\snippet doc/src/snippets/code/doc_src_q3ptrlist.cpp 1
Q3PtrList has several member functions for traversing the list, but
using a Q3PtrListIterator can be more practical. Multiple list
iterators may traverse the same list, independently of each other
and of the current list item.
In the example above we make the call setAutoDelete(true).
Enabling auto-deletion tells the list to delete items that are
removed. The default is to not delete items when they are removed
but this would cause a memory leak in the example because there
are no other references to the list items.
When inserting an item into a list only the pointer is copied, not
the item itself, i.e. a shallow copy. It is possible to make the
list copy all of the item's data (deep copy) when an item is
inserted. insert(), inSort() and append() call the virtual
function Q3PtrCollection::newItem() for the item to be inserted.
Inherit a list and reimplement newItem() to have deep copies.
When removing an item from a list, the virtual function
Q3PtrCollection::deleteItem() is called. Q3PtrList's default
implementation is to delete the item if auto-deletion is enabled.
The virtual function compareItems() can be reimplemented to
compare two list items. This function is called from all list
functions that need to compare list items, for instance
remove(const type*). If you only want to deal with pointers, there
are functions that compare pointers instead, for instance
removeRef(const type*). These functions are somewhat faster than
those that call compareItems().
List items are stored as \c void* in an internal Q3LNode, which
also holds pointers to the next and previous list items. The
functions currentNode(), removeNode(), and takeNode() operate
directly on the Q3LNode, but they should be used with care. The
data component of the node is available through Q3LNode's getData()
function.
The Q3StrList class is a list of \c char*.
It reimplements newItem(), deleteItem() and compareItems(). (But
see QStringList for a list of Unicode QStrings.)
\sa Q3PtrListIterator
*/
/*!
\fn Q3PtrList::Q3PtrList()
Constructs an empty list.
*/
/*!
\fn Q3PtrList::Q3PtrList( const Q3PtrList<type> &list )
Constructs a copy of \a list.
Each item in \a list is \link append() appended\endlink to this
list. Only the pointers are copied (shallow copy).
*/
/*!
\fn Q3PtrList::~Q3PtrList()
Removes all items from the list and destroys the list.
All list iterators that access this list will be reset.
\sa setAutoDelete()
*/
/*!
\fn Q3PtrList<type> &Q3PtrList::operator=(const Q3PtrList<type> &list)
Assigns \a list to this list and returns a reference to this list.
This list is first cleared and then each item in \a list is \link
append() appended\endlink to this list. Only the pointers are
copied (shallow copy) unless newItem() has been reimplemented.
*/
/*!
\fn bool Q3PtrList::operator==(const Q3PtrList<type> &list ) const
Compares this list with \a list. Returns TRUE if the lists contain
the same data; otherwise returns FALSE.
*/
/*!
\fn uint Q3PtrList::count() const
Returns the number of items in the list.
\sa isEmpty()
*/
/*!
\fn bool Q3PtrList::operator!=(const Q3PtrList<type> &list ) const
Compares this list with \a list. Returns TRUE if the lists contain
different data; otherwise returns FALSE.
*/
/*!
\fn void Q3PtrList::sort()
Sorts the list by the result of the virtual compareItems()
function.
The heap sort algorithm is used for sorting. It sorts n items with
O(n*log n) comparisons. This is the asymptotic optimal solution of
the sorting problem.
If the items in your list support operator<() and operator==(),
you might be better off with Q3SortedList because it implements the
compareItems() function for you using these two operators.
\sa inSort()
*/
/*!
\fn bool Q3PtrList::isEmpty() const
Returns TRUE if the list is empty; otherwise returns FALSE.
\sa count()
*/
/*!
\fn bool Q3PtrList::insert( uint index, const type *item )
Inserts the \a item at position \a index in the list.
Returns TRUE if successful, i.e. if \a index is in range;
otherwise returns FALSE. The valid range is 0 to count()
(inclusively). The item is appended if \a index == count().
The inserted item becomes the current list item.
\a item must not be 0.
\sa append(), current(), replace()
*/
/*!
\fn bool Q3PtrList::replace( uint index, const type *item )
Replaces the item at position \a index with the new \a item.
Returns TRUE if successful, i.e. \a index is in the range 0 to
count()-1.
\sa append(), current(), insert()
*/
/*!
\fn void Q3PtrList::inSort( const type *item )
Inserts the \a item at its sorted position in the list.
The sort order depends on the virtual compareItems() function. All
items must be inserted with inSort() to maintain the sorting
order.
The inserted item becomes the current list item.
\a item must not be 0.
\warning Using inSort() is slow. An alternative, especially if you
have lots of items, is to simply append() or insert() them and
then use sort(). inSort() takes up to O(n) compares. That means
inserting n items in your list will need O(n^2) compares whereas
sort() only needs O(n*log n) for the same task. So use inSort()
only if you already have a presorted list and want to insert just
a few additional items.
\sa insert(), compareItems(), current(), sort()
*/
/*!
\fn void Q3PtrList::append( const type *item )
Inserts the \a item at the end of the list.
The inserted item becomes the current list item. This is
equivalent to \c{insert( count(), item )}.
\a item must not be 0.
\sa insert(), current(), prepend()
*/
/*!
\fn void Q3PtrList::prepend( const type *item )
Inserts the \a item at the start of the list.
The inserted item becomes the current list item. This is
equivalent to \c{insert( 0, item )}.
\a item must not be 0.
\sa append(), insert(), current()
*/
/*!
\fn bool Q3PtrList::remove( uint index )
Removes the item at position \a index in the list.
Returns TRUE if successful, i.e. if \a index is in range;
otherwise returns FALSE. The valid range is \c{0..(count() - 1)}
inclusive.
The removed item is deleted if \link setAutoDelete()
auto-deletion\endlink is enabled.
The item after the removed item becomes the new current list item
if the removed item is not the last item in the list. If the last
item is removed, the new last item becomes the current item.
All list iterators that refer to the removed item will be set to
point to the new current item.
\sa take(), clear(), setAutoDelete(), current() removeRef()
*/
/*!
\fn bool Q3PtrList::remove()
\overload
Removes the current list item.
Returns TRUE if successful, i.e. if the current item isn't 0;
otherwise returns FALSE.
The removed item is deleted if \link setAutoDelete()
auto-deletion\endlink is enabled.
The item after the removed item becomes the new current list item
if the removed item is not the last item in the list. If the last
item is removed, the new last item becomes the current item. The
current item is set to 0 if the list becomes empty.
All list iterators that refer to the removed item will be set to
point to the new current item.
\sa take(), clear(), setAutoDelete(), current() removeRef()
*/
/*!
\fn bool Q3PtrList::remove( const type *item )
\overload
Removes the first occurrence of \a item from the list.
Returns TRUE if successful, i.e. if \a item is in the list;
otherwise returns FALSE.
The removed item is deleted if \link setAutoDelete()
auto-deletion\endlink is enabled.
The compareItems() function is called when searching for the item
in the list. If compareItems() is not reimplemented, it is more
efficient to call removeRef().
If \a item is NULL then the current item is removed from the list.
The item after the removed item becomes the new current list item
if the removed item is not the last item in the list. If the last
item is removed, the new last item becomes the current item. The
current item is set to 0 if the list becomes empty.
All list iterators that refer to the removed item will be set to
point to the new current item.
\sa removeRef(), take(), clear(), setAutoDelete(), compareItems(),
current()
*/
/*!
\fn bool Q3PtrList::removeRef( const type *item )
Removes the first occurrence of \a item from the list.
Returns TRUE if successful, i.e. if \a item is in the list;
otherwise returns FALSE.
The removed item is deleted if \link setAutoDelete()
auto-deletion\endlink is enabled.
Equivalent to:
\snippet doc/src/snippets/code/doc_src_q3ptrlist.cpp 2
The item after the removed item becomes the new current list item
if the removed item is not the last item in the list. If the last
item is removed, the new last item becomes the current item. The
current item is set to 0 if the list becomes empty.
All list iterators that refer to the removed item will be set to
point to the new current item.
\sa remove(), clear(), setAutoDelete(), current()
*/
/*!
\fn void Q3PtrList::removeNode( Q3LNode *node )
Removes the \a node from the list.
This node must exist in the list, otherwise the program may crash.
The removed item is deleted if \link setAutoDelete()
auto-deletion\endlink is enabled.
The first item in the list will become the new current list item.
The current item is set to 0 if the list becomes empty.
All list iterators that refer to the removed item will be set to
point to the item succeeding this item or to the preceding item if
the removed item was the last item.
\warning Do not call this function unless you are an expert.
\sa takeNode(), currentNode() remove() removeRef()
*/
/*!
\fn bool Q3PtrList::removeFirst()
Removes the first item from the list. Returns TRUE if successful,
i.e. if the list isn't empty; otherwise returns FALSE.
The removed item is deleted if \link setAutoDelete()
auto-deletion\endlink is enabled.
The first item in the list becomes the new current list item. The
current item is set to 0 if the list becomes empty.
All list iterators that refer to the removed item will be set to
point to the new current item.
\sa removeLast(), setAutoDelete(), current() remove()
*/
/*!
\fn bool Q3PtrList::removeLast()
Removes the last item from the list. Returns TRUE if successful,
i.e. if the list isn't empty; otherwise returns FALSE.
The removed item is deleted if \link setAutoDelete()
auto-deletion\endlink is enabled.
The last item in the list becomes the new current list item. The
current item is set to 0 if the list becomes empty.
All list iterators that refer to the removed item will be set to
point to the new current item.
\sa removeFirst(), setAutoDelete(), current()
*/
/*!
\fn type *Q3PtrList::take( uint index )
Takes the item at position \a index out of the list without
deleting it (even if \link setAutoDelete() auto-deletion\endlink
is enabled).
Returns a pointer to the item taken out of the list, or 0 if the
index is out of range. The valid range is \c{0..(count() - 1)}
inclusive.
The item after the removed item becomes the new current list item
if the removed item is not the last item in the list. If the last
item is removed, the new last item becomes the current item. The
current item is set to 0 if the list becomes empty.
All list iterators that refer to the taken item will be set to
point to the new current item.
\sa remove(), clear(), current()
*/
/*!
\fn type *Q3PtrList::take()
\overload
Takes the current item out of the list without deleting it (even
if \link setAutoDelete() auto-deletion\endlink is enabled).
Returns a pointer to the item taken out of the list, or 0 if
the current item is 0.
The item after the removed item becomes the new current list item
if the removed item is not the last item in the list. If the last
item is removed, the new last item becomes the current item. The
current item is set to 0 if the list becomes empty.
All list iterators that refer to the taken item will be set to
point to the new current item.
\sa remove(), clear(), current()
*/
/*!
\fn type *Q3PtrList::takeNode( Q3LNode *node )
Takes the \a node out of the list without deleting its item (even
if \link setAutoDelete() auto-deletion\endlink is enabled).
Returns a pointer to the item taken out of the list.
This node must exist in the list, otherwise the program may crash.
The first item in the list becomes the new current list item.
All list iterators that refer to the taken item will be set to
point to the item succeeding this item or to the preceding item if
the taken item was the last item.
\warning Do not call this function unless you are an expert.
\sa removeNode(), currentNode()
*/
/*!
\fn void Q3PtrList::clear()
Removes all items from the list.
The removed items are deleted if \link setAutoDelete()
auto-deletion\endlink is enabled.
All list iterators that access this list will be reset.
\sa remove(), take(), setAutoDelete()
*/
/*!
\fn int Q3PtrList::find( const type *item )
Finds the first occurrence of \a item in the list.
If the item is found, the list sets the current item to point to
the found item and returns the index of this item. If the item is
not found, the list sets the current item to 0, the current
index to -1, and returns -1.
The compareItems() function is called when searching for the item
in the list. If compareItems() is not reimplemented, it is more
efficient to call findRef().
\sa findNext(), findRef(), compareItems(), current()
*/
/*!
\fn int Q3PtrList::findNext( const type *item )
Finds the next occurrence of \a item in the list, starting from
the current list item.
If the item is found, the list sets the current item to point to
the found item and returns the index of this item. If the item is
not found, the list sets the current item to 0, the current
index to -1, and returns -1.
The compareItems() function is called when searching for the item
in the list. If compareItems() is not reimplemented, it is more
efficient to call findNextRef().
\sa find(), findNextRef(), compareItems(), current()
*/
/*!
\fn int Q3PtrList::findRef( const type *item )
Finds the first occurrence of \a item in the list.
If the item is found, the list sets the current item to point to
the found item and returns the index of this item. If the item is
not found, the list sets the current item to 0, the current
index to -1, and returns -1.
Calling this function is much faster than find() because find()
compares \a item with each list item using compareItems(), whereas
this function only compares the pointers.
\sa findNextRef(), find(), current()
*/
/*!
\fn int Q3PtrList::findNextRef( const type *item )
Finds the next occurrence of \a item in the list, starting from
the current list item.
If the item is found, the list sets the current item to point to
the found item and returns the index of this item. If the item is
not found, the list sets the current item to 0, the current
index to -1, and returns -1.
Calling this function is much faster than findNext() because
findNext() compares \a item with each list item using
compareItems(), whereas this function only compares the pointers.
\sa findRef(), findNext(), current()
*/
/*!
\fn uint Q3PtrList::contains( const type *item ) const
Returns the number of occurrences of \a item in the list.
The compareItems() function is called when looking for the \a item
in the list. If compareItems() is not reimplemented, it is more
efficient to call containsRef().
This function does not affect the current list item.
\sa containsRef(), compareItems()
*/
/*!
\fn uint Q3PtrList::containsRef( const type *item ) const
Returns the number of occurrences of \a item in the list.
Calling this function is much faster than contains() because
contains() compares \a item with each list item using
compareItems(), whereas his function only compares the pointers.
This function does not affect the current list item.
\sa contains()
*/
/*!
\fn type *Q3PtrList::at( uint index )
Returns a pointer to the item at position \a index in the list, or
0 if the index is out of range.
Sets the current list item to this item if \a index is valid. The
valid range is \c{0..(count() - 1)} inclusive.
This function is very efficient. It starts scanning from the first
item, last item, or current item, whichever is closest to \a
index.
\sa current()
*/
/*!
\fn int Q3PtrList::at() const
\overload
Returns the index of the current list item. The returned value is
-1 if the current item is 0.
\sa current()
*/
/*!
\fn type *Q3PtrList::current() const
Returns a pointer to the current list item. The current item may
be 0 (implies that the current index is -1).
\sa at()
*/
/*!
\fn Q3LNode *Q3PtrList::currentNode() const
Returns a pointer to the current list node.
The node can be kept and removed later using removeNode(). The
advantage is that the item can be removed directly without
searching the list.
\warning Do not call this function unless you are an expert.
\sa removeNode(), takeNode(), current()
*/
/*!
\fn type *Q3PtrList::getFirst() const
Returns a pointer to the first item in the list, or 0 if the list
is empty.
This function does not affect the current list item.
\sa first(), getLast()
*/
/*!
\fn type *Q3PtrList::getLast() const
Returns a pointer to the last item in the list, or 0 if the list
is empty.
This function does not affect the current list item.
\sa last(), getFirst()
*/
/*!
\fn type *Q3PtrList::first()
Returns a pointer to the first item in the list and makes this the
current list item; returns 0 if the list is empty.
\sa getFirst(), last(), next(), prev(), current()
*/
/*!
\fn type *Q3PtrList::last()
Returns a pointer to the last item in the list and makes this the
current list item; returns 0 if the list is empty.
\sa getLast(), first(), next(), prev(), current()
*/
/*!
\fn type *Q3PtrList::next()
Returns a pointer to the item succeeding the current item. Returns
0 if the current item is 0 or equal to the last item.
Makes the succeeding item current. If the current item before this
function call was the last item, the current item will be set to
0. If the current item was 0, this function does nothing.
\sa first(), last(), prev(), current()
*/
/*!
\fn type *Q3PtrList::prev()
Returns a pointer to the item preceding the current item. Returns
0 if the current item is 0 or equal to the first item.
Makes the preceding item current. If the current item before this
function call was the first item, the current item will be set to
0. If the current item was 0, this function does nothing.
\sa first(), last(), next(), current()
*/
/*!
\fn void Q3PtrList::toVector( Q3GVector *vec ) const
Stores all list items in the vector \a vec.
The vector must be of the same item type, otherwise the result
will be undefined.
*/
/*!
\typedef Q3PtrList::iterator
\internal
*/
/*!
\typedef Q3PtrList::Iterator
\internal
*/
/*!
\typedef Q3PtrList::ConstIterator
\internal
*/
/*!
\typedef Q3PtrList::const_iterator
\internal
*/
/*!
\fn Q3PtrList::constBegin() const
\internal
*/
/*!
\fn Q3PtrList::constEnd() const
\internal
*/
/*!
\fn Q3PtrList::erase(Iterator)
\internal
*/
/*****************************************************************************
Q3PtrListIterator documentation
*****************************************************************************/
/*!
\class Q3PtrListIterator
\brief The Q3PtrListIterator class provides an iterator for
Q3PtrList collections.
\compat
Define a template instance Q3PtrListIterator\<X\> to create a list
iterator that operates on Q3PtrList\<X\> (list of X*).
The following example is similar to the
example in the Q3PtrList class documentation,
but it uses Q3PtrListIterator. The class Employee is
defined there.
\snippet doc/src/snippets/code/doc_src_q3ptrlist.cpp 3
The output is
\snippet doc/src/snippets/code/doc_src_q3ptrlist.cpp 4
Using a list iterator is a more robust way of traversing the list
than using the Q3PtrList member functions \link Q3PtrList::first()
first\endlink(), \link Q3PtrList::next() next\endlink(), \link
Q3PtrList::current() current\endlink(), etc., as many iterators can
traverse the same list independently.
An iterator has its own current list item and can get the next and
previous list items. It doesn't modify the list in any way.
When an item is removed from the list, all iterators that point to
that item are updated to point to Q3PtrList::current() instead to
avoid dangling references.
\sa Q3PtrList
*/
/*!
\fn Q3PtrListIterator::Q3PtrListIterator( const Q3PtrList<type> &list )
Constructs an iterator for \a list. The current iterator item is
set to point on the first item in the \a list.
*/
/*!
\fn Q3PtrListIterator::~Q3PtrListIterator()
Destroys the iterator.
*/
/*!
\fn uint Q3PtrListIterator::count() const
Returns the number of items in the list this iterator operates on.
\sa isEmpty()
*/
/*!
\fn bool Q3PtrListIterator::isEmpty() const
Returns TRUE if the list is empty; otherwise returns FALSE.
\sa count()
*/
/*!
\fn bool Q3PtrListIterator::atFirst() const
Returns TRUE if the current iterator item is the first list item;
otherwise returns FALSE.
\sa toFirst(), atLast()
*/
/*!
\fn bool Q3PtrListIterator::atLast() const
Returns TRUE if the current iterator item is the last list item;
otherwise returns FALSE.
\sa toLast(), atFirst()
*/
/*!
\fn type *Q3PtrListIterator::toFirst()
Sets the current iterator item to point to the first list item and
returns a pointer to the item. Sets the current item to 0 and
returns 0 if the list is empty.
\sa toLast(), atFirst()
*/
/*!
\fn type *Q3PtrListIterator::toLast()
Sets the current iterator item to point to the last list item and
returns a pointer to the item. Sets the current item to 0 and
returns 0 if the list is empty.
\sa toFirst(), atLast()
*/
/*!
\fn Q3PtrListIterator::operator type *() const
Cast operator. Returns a pointer to the current iterator item.
Same as current().
*/
/*!
\fn type *Q3PtrListIterator::operator*()
Asterisk operator. Returns a pointer to the current iterator item.
Same as current().
*/
/*!
\fn type *Q3PtrListIterator::current() const
Returns a pointer to the current iterator item. If the iterator is
positioned before the first item in the list or after the last
item in the list, 0 is returned.
*/
/*!
\fn type *Q3PtrListIterator::operator()()
Makes the succeeding item current and returns the original current
item.
If the current iterator item was the last item in the list or if
it was 0, 0 is returned.
*/
/*!
\fn type *Q3PtrListIterator::operator++()
Prefix ++ makes the succeeding item current and returns the new
current item.
If the current iterator item was the last item in the list or if
it was 0, 0 is returned.
*/
/*!
\fn type *Q3PtrListIterator::operator+=( uint jump )
Sets the current item to the item \a jump positions after the
current item and returns a pointer to that item.
If that item is beyond the last item or if the list is empty, it
sets the current item to 0 and returns 0
*/
/*!
\fn type *Q3PtrListIterator::operator--()
Prefix - makes the preceding item current and returns the new
current item.
If the current iterator item was the first item in the list or if
it was 0, 0 is returned.
*/
/*!
\fn type *Q3PtrListIterator::operator-=( uint jump )
Returns the item \a jump positions before the current item or 0
if it is beyond the first item. Makes this the current item.
*/
/*!
\fn Q3PtrListIterator<type>& Q3PtrListIterator::operator=( const Q3PtrListIterator<type> &it )
Assignment. Makes a copy of the iterator \a it and returns a
reference to this iterator.
*/
/*!
\class Q3StrList
\brief The Q3StrList class provides a doubly-linked list of char*.
\compat
If you want a string list of \l{QString}s use QStringList.
This class is a Q3PtrList\<char\> instance (a list of char*).
Q3StrList can make deep or shallow copies of the strings that are
inserted.
A deep copy means that memory is allocated for the string and then
the string data is copied into that memory. A shallow copy is just
a copy of the pointer value and not of the string data itself.
The disadvantage of shallow copies is that because a pointer can
be deleted only once, the program must put all strings in a
central place and know when it is safe to delete them (i.e. when
the strings are no longer referenced by other parts of the
program). This can make the program more complex. The advantage of
shallow copies is that they consume far less memory than deep
copies. It is also much faster to copy a pointer (typically 4 or 8
bytes) than to copy string data.
A Q3StrList that operates on deep copies will, by default, turn on
auto-deletion (see setAutoDelete()). Thus, by default Q3StrList
will deallocate any string copies it allocates.
The virtual compareItems() function is reimplemented and does a
case-sensitive string comparison. The inSort() function will
insert strings in sorted order. In general it is fastest to insert
the strings as they come and sort() at the end; inSort() is useful
when you just have to add a few extra strings to an already sorted
list.
The Q3StrListIterator class is an iterator for Q3StrList.
*/
/*!
\fn Q3StrList::operator QList<QByteArray>() const
Automatically converts a Q3StrList into a QList<QByteArray>.
*/
/*!
\fn Q3StrList::Q3StrList( bool deepCopies )
Constructs an empty list of strings. Will make deep copies of all
inserted strings if \a deepCopies is TRUE, or use shallow copies
if \a deepCopies is FALSE.
*/
/*!
\fn Q3StrList::Q3StrList(const Q3StrList &list)
\fn Q3StrList::Q3StrList(const QList<QByteArray> &list)
Constructs a copy of \a list.
*/
/*!
\fn Q3StrList::~Q3StrList()
Destroys the list. All strings are removed.
*/
/*!
\fn Q3StrList& Q3StrList::operator=(const Q3StrList& list)
\fn Q3StrList &Q3StrList::operator=(const QList<QByteArray> &list)
Assigns \a list to this list and returns a reference to this list.
*/
/*!
\class Q3StrIList
\brief The Q3StrIList class provides a doubly-linked list of char*
with case-insensitive comparison.
\compat
This class is a Q3PtrList\<char\> instance (a list of char*).
Q3StrIList is identical to Q3StrList except that the virtual
compareItems() function is reimplemented to compare strings
case-insensitively. The inSort() function inserts strings in a
sorted order. In general it is fastest to insert the strings as
they come and sort() at the end; inSort() is useful when you just
have to add a few extra strings to an already sorted list.
The Q3StrListIterator class works for Q3StrIList.
\sa QStringList
*/
/*!
\fn Q3StrIList::Q3StrIList( bool deepCopies )
Constructs a list of strings. Will make deep copies of all
inserted strings if \a deepCopies is TRUE, or use shallow copies
if \a deepCopies is FALSE.
*/
/*!
\fn Q3StrIList::~Q3StrIList()
Destroys the list. All strings are removed.
*/
/*!
\fn int Q3PtrList::compareItems( Q3PtrCollection::Item item1,
Q3PtrCollection::Item item2 )
This virtual function compares two list items.
Returns:
\list
\i zero if \a item1 == \a item2
\i nonzero if \a item1 != \a item2
\endlist
This function returns \e int rather than \e bool so that
reimplementations can return three values and use it to sort by:
\list
\i 0 if \a item1 == \a item2
\i \> 0 (positive integer) if \a item1 \> \a item2
\i \< 0 (negative integer) if \a item1 \< \a item2
\endlist
inSort() requires that compareItems() is implemented as described
here.
This function should not modify the list because some const
functions call compareItems().
The default implementation compares the pointers.
*/
/*!
\fn QDataStream& Q3PtrList::read( QDataStream& s,
Q3PtrCollection::Item& item )
Reads a list item from the stream \a s and returns a reference to
the stream.
The default implementation sets \a item to 0.
\sa write()
*/
/*!
\fn QDataStream& Q3PtrList::write( QDataStream& s,
Q3PtrCollection::Item item ) const
Writes a list item, \a item to the stream \a s and returns a
reference to the stream.
The default implementation does nothing.
\sa read()
*/
/*! \fn iterator Q3PtrList::begin()
\internal
*/
/*! \fn const_iterator Q3PtrList::begin() const
\internal
*/
/*! \fn iterator Q3PtrList::end()
\internal
*/
/*! \fn const_iterator Q3PtrList::end() const
\internal
*/
/*!
\class Q3StrListIterator
\brief The Q3StrListIterator class is an iterator for the Q3StrList
and Q3StrIList classes.
\compat
This class is a Q3PtrListIterator\<char\> instance. It can traverse
the strings in the Q3StrList and Q3StrIList classes.
*/
/*
\class Q3PtrListAutoDelete
\brief The Q3PtrListAutoDelete class is a template class that provides a list that auto-deletes its data.
\compat
A Q3PtrListAutoDelete is identical to a Q3PtrList with
setAutoDelete(TRUE).
*/
|