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1 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2 %% Name: array.tex
3 %% Purpose: wxArray
4 %% Author: wxWidgets Team
5 %% Modified by:
6 %% Created:
7 %% RCS-ID: $Id$
8 %% Copyright: (c) wxWidgets Team
9 %% License: wxWindows license
10 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
11
12 \section{\class{wxArray<T>}}\label{wxarray}
13
14 This section describes the so called {\it dynamic arrays}. This is a C
15 array-like type safe data structure i.e. the member access time is constant (and not
16 linear according to the number of container elements as for linked lists). However, these
17 arrays are dynamic in the sense that they will automatically allocate more
18 memory if there is not enough of it for adding a new element. They also perform
19 range checking on the index values but in debug mode only, so please be sure to
20 compile your application in debug mode to use it (see \helpref{debugging overview}{debuggingoverview} for
21 details). So, unlike the arrays in some other
22 languages, attempt to access an element beyond the arrays bound doesn't
23 automatically expand the array but provokes an assertion failure instead in
24 debug build and does nothing (except possibly crashing your program) in the
25 release build.
26
27 The array classes were designed to be reasonably efficient, both in terms of
28 run-time speed and memory consumption and the executable size. The speed of
29 array item access is, of course, constant (independent of the number of elements)
30 making them much more efficient than linked lists (\helpref{wxList}{wxlist}).
31 Adding items to the arrays is also implemented in more or less constant time -
32 but the price is preallocating the memory in advance. In the \helpref{memory management}{wxarraymemorymanagement} section
33 you may find some useful hints about optimizing wxArray memory usage. As for executable size, all
34 wxArray functions are inline, so they do not take {\it any space at all}.
35
36 wxWidgets has three different kinds of array. All of them derive from
37 wxBaseArray class which works with untyped data and can not be used directly.
38 The standard macros WX\_DEFINE\_ARRAY(), WX\_DEFINE\_SORTED\_ARRAY() and
39 WX\_DEFINE\_OBJARRAY() are used to define a new class deriving from it. The
40 classes declared will be called in this documentation wxArray, wxSortedArray and
41 wxObjArray but you should keep in mind that no classes with such names actually
42 exist, each time you use one of WX\_DEFINE\_XXXARRAY macro you define a class
43 with a new name. In fact, these names are "template" names and each usage of one
44 of the macros mentioned above creates a template specialization for the given
45 element type.
46
47 wxArray is suitable for storing integer types and pointers which it does not
48 treat as objects in any way, i.e. the element pointed to by the pointer is not
49 deleted when the element is removed from the array. It should be noted that
50 all of wxArray's functions are inline, so it costs strictly nothing to define as
51 many array types as you want (either in terms of the executable size or the
52 speed) as long as at least one of them is defined and this is always the case
53 because wxArrays are used by wxWidgets internally. This class has one serious
54 limitation: it can only be used for storing integral types (bool, char, short,
55 int, long and their unsigned variants) or pointers (of any kind). An attempt
56 to use with objects of sizeof() greater than sizeof(long) will provoke a
57 runtime assertion failure, however declaring a wxArray of floats will not (on
58 the machines where sizeof(float) <= sizeof(long)), yet it will {\bf not} work,
59 please use wxObjArray for storing floats and doubles.
60
61 wxSortedArray is a wxArray variant which should be used when searching in the
62 array is a frequently used operation. It requires you to define an additional
63 function for comparing two elements of the array element type and always stores
64 its items in the sorted order (according to this function). Thus, it is
65 \helpref{Index()}{wxarrayindex} function execution time is $O(log(N))$ instead of
66 $O(N)$ for the usual arrays but the \helpref{Add()}{wxarrayadd} method is
67 slower: it is $O(log(N))$ instead of constant time (neglecting time spent in
68 memory allocation routine). However, in a usual situation elements are added to
69 an array much less often than searched inside it, so wxSortedArray may lead to
70 huge performance improvements compared to wxArray. Finally, it should be
71 noticed that, as wxArray, wxSortedArray can be only used for storing integral
72 types or pointers.
73
74 wxObjArray class treats its elements like "objects". It may delete them when
75 they are removed from the array (invoking the correct destructor) and copies
76 them using the objects copy constructor. In order to implement this behaviour
77 the definition of the wxObjArray arrays is split in two parts: first, you should
78 declare the new wxObjArray class using WX\_DECLARE\_OBJARRAY() macro and then
79 you must include the file defining the implementation of template type:
80 <wx/arrimpl.cpp> and define the array class with WX\_DEFINE\_OBJARRAY() macro
81 from a point where the full (as opposed to `forward') declaration of the array
82 elements class is in scope. As it probably sounds very complicated here is an
83 example:
84
85 \begin{verbatim}
86 #include <wx/dynarray.h>
87
88 // we must forward declare the array because it is used inside the class
89 // declaration
90 class MyDirectory;
91 class MyFile;
92
93 // this defines two new types: ArrayOfDirectories and ArrayOfFiles which can be
94 // now used as shown below
95 WX_DECLARE_OBJARRAY(MyDirectory, ArrayOfDirectories);
96 WX_DECLARE_OBJARRAY(MyFile, ArrayOfFiles);
97
98 class MyDirectory
99 {
100 ...
101 ArrayOfDirectories m_subdirectories; // all subdirectories
102 ArrayOfFiles m_files; // all files in this directory
103 };
104
105 ...
106
107 // now that we have MyDirectory declaration in scope we may finish the
108 // definition of ArrayOfDirectories -- note that this expands into some C++
109 // code and so should only be compiled once (i.e., don't put this in the
110 // header, but into a source file or you will get linking errors)
111 #include <wx/arrimpl.cpp> // this is a magic incantation which must be done!
112 WX_DEFINE_OBJARRAY(ArrayOfDirectories);
113
114 // that's all!
115 \end{verbatim}
116
117 It is not as elegant as writing
118
119 \begin{verbatim}
120 typedef std::vector<MyDirectory> ArrayOfDirectories;
121 \end{verbatim}
122
123 but is not that complicated and allows the code to be compiled with any, however
124 dumb, C++ compiler in the world.
125
126 Remember to #include <wx/arrimpl.cpp> just before each WX\_DEFINE\_OBJARRAY
127 ocurrence in your code, even if you have several in the same file.
128
129 Things are much simpler for wxArray and wxSortedArray however: it is enough
130 just to write
131
132 \begin{verbatim}
133 WX_DEFINE_ARRAY_INT(int, ArrayOfInts);
134 WX_DEFINE_SORTED_ARRAY_INT(int, ArrayOfSortedInts);
135 \end{verbatim}
136
137 i.e. there is only one {\tt DEFINE} macro and no need for separate
138 {\tt DECLARE} one. For the arrays of the primitive types, the macros
139 {\tt WX\_DEFINE\_ARRAY\_CHAR/SHORT/INT/SIZE\_T/LONG/DOUBLE} should be used
140 depending on the sizeof of the values (notice that storing values of smaller
141 type, e.g. shorts, in an array of larger one, e.g. {\tt ARRAY\_INT}, does
142 \emph{not} work on all architectures!).
143
144
145 \wxheading{See also}
146
147 \helpref{Container classes overview}{wxcontaineroverview},
148 \helpref{wxList<T>}{wxlist},
149 \helpref{wxVector<T>}{wxvector}
150
151 \wxheading{Include files}
152
153 <wx/dynarray.h> for wxArray and wxSortedArray and additionally <wx/arrimpl.cpp>
154 for wxObjArray.
155
156 \wxheading{Library}
157
158 \helpref{wxBase}{librarieslist}
159
160
161
162
163 \latexignore{\rtfignore{\wxheading{Function groups}}}
164
165 \membersection{Macros for template array definition}\label{arraymacros}
166
167 To use an array you must first define the array class. This is done with the
168 help of the macros in this section. The class of array elements must be (at
169 least) forward declared for WX\_DEFINE\_ARRAY, WX\_DEFINE\_SORTED\_ARRAY and
170 WX\_DECLARE\_OBJARRAY macros and must be fully declared before you use
171 WX\_DEFINE\_OBJARRAY macro.
172
173 \helpref{WX\_DEFINE\_ARRAY}{wxdefinearray}\\
174 \helpref{WX\_DEFINE\_EXPORTED\_ARRAY}{wxdefinearray}\\
175 \helpref{WX\_DEFINE\_USER\_EXPORTED\_ARRAY}{wxdefinearray}\\
176 \helpref{WX\_DEFINE\_SORTED\_ARRAY}{wxdefinesortedarray}\\
177 \helpref{WX\_DEFINE\_SORTED\_EXPORTED\_ARRAY}{wxdefinesortedarray}\\
178 \helpref{WX\_DEFINE\_SORTED\_USER\_EXPORTED\_ARRAY}{wxdefinesortedarray}\\
179 \helpref{WX\_DECLARE\_EXPORTED\_OBJARRAY}{wxdeclareobjarray}\\
180 \helpref{WX\_DECLARE\_USER\_EXPORTED\_OBJARRAY}{wxdeclareobjarray}\\
181 \helpref{WX\_DEFINE\_OBJARRAY}{wxdefineobjarray}\\
182 \helpref{WX\_DEFINE\_EXPORTED\_OBJARRAY}{wxdefineobjarray}\\
183 \helpref{WX\_DEFINE\_USER\_EXPORTED\_OBJARRAY}{wxdefineobjarray}
184
185 To slightly complicate the matters even further, the operator $->$ defined by
186 default for the array iterators by these macros only makes sense if the array
187 element type is not a pointer itself and, although it still works, this
188 provokes warnings from some compilers and to avoid them you should use the
189 {\tt \_PTR} versions of the macros above. For example, to define an array of
190 pointers to {\tt double} you should use:
191
192 \begin{verbatim}
193 WX_DEFINE_ARRAY_PTR(double *, MyArrayOfDoublePointers);
194 \end{verbatim}
195
196 Note that the above macros are generally only useful for
197 wxObject types. There are separate macros for declaring an array of a simple type,
198 such as an int.
199
200 The following simple types are supported:\\
201 int\\
202 long\\
203 size\_t\\
204 double
205
206 To create an array of a simple type, simply append the type you want in CAPS to
207 the array definition.
208
209 For example, for an integer array, you'd use one of the following variants:
210
211 \helpref{WX\_DEFINE\_ARRAY\_INT}{wxdefinearray}\\
212 \helpref{WX\_DEFINE\_EXPORTED\_ARRAY\_INT}{wxdefinearray}\\
213 \helpref{WX\_DEFINE\_USER\_EXPORTED\_ARRAY\_INT}{wxdefinearray}\\
214 \helpref{WX\_DEFINE\_SORTED\_ARRAY\_INT}{wxdefinesortedarray}\\
215 \helpref{WX\_DEFINE\_SORTED\_EXPORTED\_ARRAY\_INT}{wxdefinesortedarray}\\
216 \helpref{WX\_DEFINE\_SORTED\_USER\_EXPORTED\_ARRAY\_INT}{wxdefinesortedarray}\\
217
218 \membersection{Constructors and destructors}\label{arrayconstructorsdestructors}
219
220 Array classes are 100\% C++ objects and as such they have the appropriate copy
221 constructors and assignment operators. Copying wxArray just copies the elements
222 but copying wxObjArray copies the arrays items. However, for memory-efficiency
223 sake, neither of these classes has virtual destructor. It is not very important
224 for wxArray which has trivial destructor anyhow, but it does mean that you
225 should avoid deleting wxObjArray through a wxBaseArray pointer (as you would
226 never use wxBaseArray anyhow it shouldn't be a problem) and that you should not
227 derive your own classes from the array classes.
228
229 \helpref{wxArray default constructor}{wxarrayctordef}\\
230 \helpref{wxArray copy constructors and assignment operators}{wxarrayctorcopy}\\
231 \helpref{\destruct{wxArray}}{wxarraydtor}
232
233 \membersection{Memory management}\label{wxarraymemorymanagement}
234
235 Automatic array memory management is quite trivial: the array starts by
236 preallocating some minimal amount of memory (defined by
237 WX\_ARRAY\_DEFAULT\_INITIAL\_SIZE) and when further new items exhaust already
238 allocated memory it reallocates it adding 50\% of the currently allocated
239 amount, but no more than some maximal number which is defined by
240 ARRAY\_MAXSIZE\_INCREMENT constant. Of course, this may lead to some memory
241 being wasted (ARRAY\_MAXSIZE\_INCREMENT in the worst case, i.e. 4Kb in the
242 current implementation), so the \helpref{Shrink()}{wxarrayshrink} function is
243 provided to deallocate the extra memory. The \helpref{Alloc()}{wxarrayalloc}
244 function can also be quite useful if you know in advance how many items you are
245 going to put in the array and will prevent the array code from reallocating the
246 memory more times than needed.
247
248 \helpref{Alloc}{wxarrayalloc}\\
249 \helpref{Shrink}{wxarrayshrink}
250
251 \membersection{Number of elements and simple item access}\label{arrayelementsaccess}
252
253 Functions in this section return the total number of array elements and allow to
254 retrieve them - possibly using just the C array indexing $[]$ operator which
255 does exactly the same as \helpref{Item()}{wxarrayitem} method.
256
257 \helpref{GetCount}{wxarraygetcount}\\
258 \helpref{IsEmpty}{wxarrayisempty}\\
259 \helpref{Item}{wxarrayitem}\\
260 \helpref{Last}{wxarraylast}
261
262 \membersection{Adding items}\label{arrayadding}
263
264 \helpref{Add}{wxarrayadd}\\
265 \helpref{AddAt}{wxarrayaddat}\\
266 \helpref{Insert}{wxarrayinsert}\\
267 \helpref{SetCount}{wxarraysetcount}\\
268 \helpref{WX\_APPEND\_ARRAY}{wxappendarray}\\
269 \helpref{WX\_PREPEND\_ARRAY}{wxprependarray}
270
271 \membersection{Removing items}\label{arrayremoving}
272
273 \helpref{WX\_CLEAR\_ARRAY}{wxcleararray}\\
274 \helpref{Empty}{wxarrayempty}\\
275 \helpref{Clear}{wxarrayclear}\\
276 \helpref{RemoveAt}{wxarrayremoveat}\\
277 \helpref{Remove}{wxarrayremove}
278
279 \membersection{Searching and sorting}\label{arraysearchingandsorting}
280
281 \helpref{Index}{wxarrayindex}\\
282 \helpref{IndexForInsert}{wxarrayindexforinsert}\\
283 \helpref{Sort}{wxarraysort}
284
285 %%%%% MEMBERS HERE %%%%%
286 \helponly{\insertatlevel{2}{
287
288 \wxheading{Members}
289
290 }}
291
292 \membersection{WX\_DEFINE\_ARRAY}\label{wxdefinearray}
293
294 \func{}{WX\_DEFINE\_ARRAY}{\param{}{T}, \param{}{name}}
295
296 \func{}{WX\_DEFINE\_EXPORTED\_ARRAY}{\param{}{T}, \param{}{name}}
297
298 \func{}{WX\_DEFINE\_USER\_EXPORTED\_ARRAY}{\param{}{T}, \param{}{name}, \param{}{exportspec}}
299
300 This macro defines a new array class named {\it name} and containing the
301 elements of type {\it T}. The second form is used when compiling wxWidgets as
302 a DLL under Windows and array needs to be visible outside the DLL. The third is
303 needed for exporting an array from a user DLL.
304
305 Example:
306
307 \begin{verbatim}
308 WX_DEFINE_ARRAY_INT(int, MyArrayInt);
309
310 class MyClass;
311 WX_DEFINE_ARRAY(MyClass *, ArrayOfMyClass);
312 \end{verbatim}
313
314 Note that wxWidgets predefines the following standard array classes: {\bf wxArrayInt},
315 {\bf wxArrayLong}, {\bf wxArrayShort}, {\bf wxArrayDouble}, {\bf wxArrayPtrVoid}.
316
317
318 \membersection{WX\_DEFINE\_SORTED\_ARRAY}\label{wxdefinesortedarray}
319
320 \func{}{WX\_DEFINE\_SORTED\_ARRAY}{\param{}{T}, \param{}{name}}
321
322 \func{}{WX\_DEFINE\_SORTED\_EXPORTED\_ARRAY}{\param{}{T}, \param{}{name}}
323
324 \func{}{WX\_DEFINE\_SORTED\_USER\_EXPORTED\_ARRAY}{\param{}{T}, \param{}{name}}
325
326 This macro defines a new sorted array class named {\it name} and containing
327 the elements of type {\it T}. The second form is used when compiling wxWidgets as
328 a DLL under Windows and array needs to be visible outside the DLL. The third is
329 needed for exporting an array from a user DLL.
330
331 Example:
332
333 \begin{verbatim}
334 WX_DEFINE_SORTED_ARRAY_INT(int, MySortedArrayInt);
335
336 class MyClass;
337 WX_DEFINE_SORTED_ARRAY(MyClass *, ArrayOfMyClass);
338 \end{verbatim}
339
340 You will have to initialize the objects of this class by passing a comparison
341 function to the array object constructor like this:
342
343 \begin{verbatim}
344 int CompareInts(int n1, int n2)
345 {
346 return n1 - n2;
347 }
348
349 MySortedArrayInt sorted(CompareInts);
350
351 int CompareMyClassObjects(MyClass *item1, MyClass *item2)
352 {
353 // sort the items by their address...
354 return Stricmp(item1->GetAddress(), item2->GetAddress());
355 }
356
357 ArrayOfMyClass another(CompareMyClassObjects);
358 \end{verbatim}
359
360 \membersection{WX\_DECLARE\_OBJARRAY}\label{wxdeclareobjarray}
361
362 \func{}{WX\_DECLARE\_OBJARRAY}{\param{}{T}, \param{}{name}}
363
364 \func{}{WX\_DECLARE\_EXPORTED\_OBJARRAY}{\param{}{T}, \param{}{name}}
365
366 \func{}{WX\_DECLARE\_USER\_EXPORTED\_OBJARRAY}{\param{}{T}, \param{}{name}}
367
368 This macro declares a new object array class named {\it name} and containing
369 the elements of type {\it T}. The second form is used when compiling wxWidgets as
370 a DLL under Windows and array needs to be visible outside the DLL. The third is
371 needed for exporting an array from a user DLL.
372
373 Example:
374
375 \begin{verbatim}
376 class MyClass;
377 WX_DECLARE_OBJARRAY(MyClass, wxArrayOfMyClass); // note: not "MyClass *"!
378 \end{verbatim}
379
380 You must use \helpref{WX\_DEFINE\_OBJARRAY()}{wxdefineobjarray} macro to define
381 the array class - otherwise you would get link errors.
382
383 \membersection{WX\_DEFINE\_OBJARRAY}\label{wxdefineobjarray}
384
385 \func{}{WX\_DEFINE\_OBJARRAY}{\param{}{name}}
386
387 \func{}{WX\_DEFINE\_EXPORTED\_OBJARRAY}{\param{}{name}}
388
389 \func{}{WX\_DEFINE\_USER\_EXPORTED\_OBJARRAY}{\param{}{name}}
390
391 This macro defines the methods of the array class {\it name} not defined by the
392 \helpref{WX\_DECLARE\_OBJARRAY()}{wxdeclareobjarray} macro. You must include the
393 file <wx/arrimpl.cpp> before using this macro and you must have the full
394 declaration of the class of array elements in scope! If you forget to do the
395 first, the error will be caught by the compiler, but, unfortunately, many
396 compilers will not give any warnings if you forget to do the second - but the
397 objects of the class will not be copied correctly and their real destructor will
398 not be called. The latter two forms are merely aliases of the first to satisfy
399 some people's sense of symmetry when using the exported declarations.
400
401 Example of usage:
402
403 \begin{verbatim}
404 // first declare the class!
405 class MyClass
406 {
407 public:
408 MyClass(const MyClass&);
409
410 ...
411
412 virtual ~MyClass();
413 };
414
415 #include <wx/arrimpl.cpp>
416 WX_DEFINE_OBJARRAY(wxArrayOfMyClass);
417 \end{verbatim}
418
419 \membersection{WX\_APPEND\_ARRAY}\label{wxappendarray}
420
421 \func{void}{WX\_APPEND\_ARRAY}{\param{wxArray\& }{array}, \param{wxArray\& }{other}}
422
423 This macro may be used to append all elements of the {\it other} array to the
424 {\it array}. The two arrays must be of the same type.
425
426 \membersection{WX\_PREPEND\_ARRAY}\label{wxprependarray}
427
428 \func{void}{WX\_PREPEND\_ARRAY}{\param{wxArray\& }{array}, \param{wxArray\& }{other}}
429
430 This macro may be used to prepend all elements of the {\it other} array to the
431 {\it array}. The two arrays must be of the same type.
432
433 \membersection{WX\_CLEAR\_ARRAY}\label{wxcleararray}
434
435 \func{void}{WX\_CLEAR\_ARRAY}{\param{wxArray\& }{array}}
436
437 This macro may be used to delete all elements of the array before emptying it.
438 It can not be used with wxObjArrays - but they will delete their elements anyhow
439 when you call Empty().
440
441 \membersection{Default constructors}\label{wxarrayctordef}
442
443 \func{}{wxArray}{\void}
444
445 \func{}{wxObjArray}{\void}
446
447 Default constructor initializes an empty array object.
448
449 \func{}{wxSortedArray}{\param{int (*)(T first, T second)}{compareFunction}}
450
451 There is no default constructor for wxSortedArray classes - you must initialize it
452 with a function to use for item comparison. It is a function which is passed
453 two arguments of type {\it T} where {\it T} is the array element type and which
454 should return a negative, zero or positive value according to whether the first
455 element passed to it is less than, equal to or greater than the second one.
456
457 \membersection{wxArray copy constructor and assignment operator}\label{wxarrayctorcopy}
458
459 \func{}{wxArray}{\param{const wxArray\& }{array}}
460
461 \func{}{wxSortedArray}{\param{const wxSortedArray\& }{array}}
462
463 \func{}{wxObjArray}{\param{const wxObjArray\& }{array}}
464
465 \func{wxArray\&}{operator$=$}{\param{const wxArray\& }{array}}
466
467 \func{wxSortedArray\&}{operator$=$}{\param{const wxSortedArray\& }{array}}
468
469 \func{wxObjArray\&}{operator$=$}{\param{const wxObjArray\& }{array}}
470
471 The copy constructors and assignment operators perform a shallow array copy
472 (i.e. they don't copy the objects pointed to even if the source array contains
473 the items of pointer type) for wxArray and wxSortedArray and a deep copy (i.e.
474 the array element are copied too) for wxObjArray.
475
476 \membersection{wxArray::\destruct{wxArray}}\label{wxarraydtor}
477
478 \func{}{\destruct{wxArray}}{\void}
479
480 \func{}{\destruct{wxSortedArray}}{\void}
481
482 \func{}{\destruct{wxObjArray}}{\void}
483
484 The wxObjArray destructor deletes all the items owned by the array. This is not
485 done by wxArray and wxSortedArray versions - you may use
486 \helpref{WX\_CLEAR\_ARRAY}{wxcleararray} macro for this.
487
488 \membersection{wxArray::Add}\label{wxarrayadd}
489
490 \func{void}{Add}{\param{T }{item}, \param{size\_t}{ copies = $1$}}
491
492 \func{size\_t}{Add}{\param{T }{item}}
493
494 \func{void}{Add}{\param{T *}{item}}
495
496 \func{void}{Add}{\param{T \&}{item}, \param{size\_t}{ copies = $1$}}
497
498 Appends the given number of {\it copies} of the {\it item} to the array
499 consisting of the elements of type {\it T}.
500
501 The first version is used with wxArray. The second is used with wxSortedArray,
502 returning the index where {\it item} is stored. The third and the
503 fourth ones are used with wxObjArray. There is an important difference between
504 them: if you give a pointer to the array, it will take ownership of it, i.e.
505 will delete it when the item is deleted from the array. If you give a reference
506 to the array, however, the array will make a copy of the item and will not take
507 ownership of the original item. Once again, it only makes sense for wxObjArrays
508 because the other array types never take ownership of their elements. Also note
509 that you cannot append more than one pointer as reusing it would lead to
510 deleting it twice (or more) and hence to a crash.
511
512 You may also use \helpref{WX\_APPEND\_ARRAY}{wxappendarray} macro to append all
513 elements of one array to another one but it is more efficient to use
514 {\it copies} parameter and modify the elements in place later if you plan to
515 append a lot of items.
516
517 \membersection{wxSortedArray::AddAt}\label{wxarrayaddat}
518
519 \func{void}{AddAt}{\param{T }{item}, \param{size\_t}{ index}}
520
521 Inserts the given {\it item} into the array in the specified {\it index}
522 position.
523
524 Be aware that you will set out the order of the array if you give a wrong
525 position.
526
527 This function is useful in conjunction with
528 \helpref{IndexForInsert}{wxarrayindexforinsert} for a common operation
529 of "insert only if not found".
530
531 \membersection{wxArray::Alloc}\label{wxarrayalloc}
532
533 \func{void}{Alloc}{\param{size\_t }{count}}
534
535 Preallocates memory for a given number of array elements. It is worth calling
536 when the number of items which are going to be added to the array is known in
537 advance because it will save unneeded memory reallocation. If the array already
538 has enough memory for the given number of items, nothing happens. In any case,
539 the existing contents of the array is not modified.
540
541 \membersection{wxArray::Clear}\label{wxarrayclear}
542
543 \func{void}{Clear}{\void}
544
545 This function does the same as \helpref{Empty()}{wxarrayempty} and additionally
546 frees the memory allocated to the array.
547
548 \membersection{wxObjArray::Detach}\label{wxobjarraydetach}
549
550 \func{T *}{Detach}{\param{size\_t }{index}}
551
552 Removes the element from the array, but, unlike,
553 \helpref{Remove()}{wxarrayremove} doesn't delete it. The function returns the
554 pointer to the removed element.
555
556 \membersection{wxArray::Empty}\label{wxarrayempty}
557
558 \func{void}{Empty}{\void}
559
560 Empties the array. For wxObjArray classes, this destroys all of the array
561 elements. For wxArray and wxSortedArray this does nothing except marking the
562 array of being empty - this function does not free the allocated memory, use
563 \helpref{Clear()}{wxarrayclear} for this.
564
565 \membersection{wxArray::GetCount}\label{wxarraygetcount}
566
567 \constfunc{size\_t}{GetCount}{\void}
568
569 Return the number of items in the array.
570
571 \membersection{wxArray::Index}\label{wxarrayindex}
572
573 \constfunc{int}{Index}{\param{T\& }{item}, \param{bool }{searchFromEnd = false}}
574
575 \constfunc{int}{Index}{\param{T\& }{item}}
576
577 The first version of the function is for wxArray and wxObjArray, the second is
578 for wxSortedArray only.
579
580 Searches the element in the array, starting from either beginning or the end
581 depending on the value of {\it searchFromEnd} parameter. {\tt wxNOT\_FOUND} is
582 returned if the element is not found, otherwise the index of the element is
583 returned.
584
585 Linear search is used for the wxArray and wxObjArray classes but binary search
586 in the sorted array is used for wxSortedArray (this is why searchFromEnd
587 parameter doesn't make sense for it).
588
589 {\bf NB:} even for wxObjArray classes, the operator==() of the elements in the
590 array is {\bf not} used by this function. It searches exactly the given
591 element in the array and so will only succeed if this element had been
592 previously added to the array, but fail even if another, identical, element is
593 in the array.
594
595 \membersection{wxSortedArray::IndexForInsert}\label{wxarrayindexforinsert}
596
597 \constfunc{size\_t}{IndexForInsert}{\param{T }{item}}
598
599 Search for a place to insert {\it item} into the sorted array (binary search).
600 The index returned is just before the first existing item that is greater or equal
601 (according to the compare function) to the given {\it item}.
602
603 You have to do extra work to know if the {\it item} already exists in array.
604
605 This function is useful in conjunction with
606 \helpref{AddAt}{wxarrayaddat} for a common operation
607 of "insert only if not found".
608
609 \membersection{wxArray::Insert}\label{wxarrayinsert}
610
611 \func{void}{Insert}{\param{T }{item}, \param{size\_t }{n}, \param{size\_t }{copies = $1$}}
612
613 \func{void}{Insert}{\param{T *}{item}, \param{size\_t }{n}}
614
615 \func{void}{Insert}{\param{T \&}{item}, \param{size\_t }{n}, \param{size\_t }{copies = $1$}}
616
617 Insert the given number of {\it copies} of the {\it item} into the array before
618 the existing item {\it n} - thus, {\it Insert(something, 0u)} will insert an
619 item in such way that it will become the first array element.
620
621 wxSortedArray doesn't have this function because inserting in wrong place
622 would break its sorted condition.
623
624 Please see \helpref{Add()}{wxarrayadd} for explanation of the differences
625 between the overloaded versions of this function.
626
627 \membersection{wxArray::IsEmpty}\label{wxarrayisempty}
628
629 \constfunc{bool}{IsEmpty}{\void}
630
631 Returns true if the array is empty, false otherwise.
632
633 \membersection{wxArray::Item}\label{wxarrayitem}
634
635 \constfunc{T\&}{Item}{\param{size\_t }{index}}
636
637 Returns the item at the given position in the array. If {\it index} is out of
638 bounds, an assert failure is raised in the debug builds but nothing special is
639 done in the release build.
640
641 The returned value is of type "reference to the array element type" for all of
642 the array classes.
643
644 \membersection{wxArray::Last}\label{wxarraylast}
645
646 \constfunc{T\&}{Last}{\void}
647
648 Returns the last element in the array, i.e. is the same as Item(GetCount() - 1).
649 An assert failure is raised in the debug mode if the array is empty.
650
651 The returned value is of type "reference to the array element type" for all of
652 the array classes.
653
654 \membersection{wxArray::Remove}\label{wxarrayremove}
655
656 \func{\void}{Remove}{\param{T }{item}}
657
658 Removes an element from the array by value: the first item of the
659 array equal to {\it item} is removed, an assert failure will result from an
660 attempt to remove an item which doesn't exist in the array.
661
662 When an element is removed from wxObjArray it is deleted by the array - use
663 \helpref{Detach()}{wxobjarraydetach} if you don't want this to happen. On the
664 other hand, when an object is removed from a wxArray nothing happens - you
665 should delete it manually if required:
666
667 \begin{verbatim}
668 T *item = array[n];
669 delete item;
670 array.Remove(n)
671 \end{verbatim}
672
673 See also \helpref{WX\_CLEAR\_ARRAY}{wxcleararray} macro which deletes all
674 elements of a wxArray (supposed to contain pointers).
675
676 \membersection{wxArray::RemoveAt}\label{wxarrayremoveat}
677
678 \func{\void}{RemoveAt}{\param{size\_t }{index}, \param{size\_t }{count = $1$}}
679
680 Removes {\it count} elements starting at {\it index} from the array. When an
681 element is removed from wxObjArray it is deleted by the array - use
682 \helpref{Detach()}{wxobjarraydetach} if you don't want this to happen. On
683 the other hand, when an object is removed from a wxArray nothing happens -
684 you should delete it manually if required:
685
686 \begin{verbatim}
687 T *item = array[n];
688 delete item;
689 array.RemoveAt(n)
690 \end{verbatim}
691
692 See also \helpref{WX\_CLEAR\_ARRAY}{wxcleararray} macro which deletes all
693 elements of a wxArray (supposed to contain pointers).
694
695 \membersection{wxArray::SetCount}\label{wxarraysetcount}
696
697 \func{void}{SetCount}{\param{size\_t }{count}, \param{T }{defval = T($0$)}}
698
699 This function ensures that the number of array elements is at least
700 {\it count}. If the array has already {\it count} or more items, nothing is
701 done. Otherwise, {\tt count - GetCount()} elements are added and initialized to
702 the value {\it defval}.
703
704 \wxheading{See also}
705
706 \helpref{GetCount}{wxarraygetcount}
707
708 \membersection{wxArray::Shrink}\label{wxarrayshrink}
709
710 \func{void}{Shrink}{\void}
711
712 Frees all memory unused by the array. If the program knows that no new items
713 will be added to the array it may call Shrink() to reduce its memory usage.
714 However, if a new item is added to the array, some extra memory will be
715 allocated again.
716
717 \membersection{wxArray::Sort}\label{wxarraysort}
718
719 \func{void}{Sort}{\param{CMPFUNC<T> }{compareFunction}}
720
721 The notation CMPFUNC<T> should be read as if we had the following declaration:
722
723 \begin{verbatim}
724 template int CMPFUNC(T *first, T *second);
725 \end{verbatim}
726
727 where {\it T} is the type of the array elements. I.e. it is a function returning
728 {\it int} which is passed two arguments of type {\it T *}.
729
730 Sorts the array using the specified compare function: this function should
731 return a negative, zero or positive value according to whether the first element
732 passed to it is less than, equal to or greater than the second one.
733
734 wxSortedArray doesn't have this function because it is always sorted.
735