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git.saurik.com Git - wxWidgets.git/blob - interface/wx/dynarray.h
1 /////////////////////////////////////////////////////////////////////////////
3 // Purpose: interface of wxArray<T>
4 // Author: wxWidgets team
5 // Licence: wxWindows licence
6 /////////////////////////////////////////////////////////////////////////////
10 This section describes the so called @e "dynamic arrays". This is a C
11 array-like type safe data structure i.e. the member access time is constant
12 (and not linear according to the number of container elements as for linked
13 lists). However, these arrays are dynamic in the sense that they will
14 automatically allocate more memory if there is not enough of it for adding
15 a new element. They also perform range checking on the index values but in
16 debug mode only, so please be sure to compile your application in debug
17 mode to use it (see @ref overview_debugging for details). So, unlike the
18 arrays in some other languages, attempt to access an element beyond the
19 arrays bound doesn't automatically expand the array but provokes an
20 assertion failure instead in debug build and does nothing (except possibly
21 crashing your program) in the release build.
23 The array classes were designed to be reasonably efficient, both in terms
24 of run-time speed and memory consumption and the executable size. The speed
25 of array item access is, of course, constant (independent of the number of
26 elements) making them much more efficient than linked lists (wxList).
27 Adding items to the arrays is also implemented in more or less constant
28 time, but the price is preallocating the memory in advance. In the
29 "memory management" function section, you may find some useful hints about
30 optimizing wxArray memory usage. As for executable size, all wxArray
31 functions are inline, so they do not take @e any space at all.
33 wxWidgets has three different kinds of array. All of them derive from
34 wxBaseArray class which works with untyped data and cannot be used
35 directly. The standard macros WX_DEFINE_ARRAY(), WX_DEFINE_SORTED_ARRAY()
36 and WX_DEFINE_OBJARRAY() are used to define a new class deriving from it.
37 The classes declared will be called in this documentation wxArray,
38 wxSortedArray and wxObjArray but you should keep in mind that no classes
39 with such names actually exist, each time you use one of the
40 WX_DEFINE_XXXARRAY() macros, you define a class with a new name. In fact,
41 these names are "template" names and each usage of one of the macros
42 mentioned above creates a template specialization for the given element
45 wxArray is suitable for storing integer types and pointers which it does
46 not treat as objects in any way, i.e. the element pointed to by the pointer
47 is not deleted when the element is removed from the array. It should be
48 noted that all of wxArray's functions are inline, so it costs strictly
49 nothing to define as many array types as you want (either in terms of the
50 executable size or the speed) as long as at least one of them is defined
51 and this is always the case because wxArrays are used by wxWidgets
52 internally. This class has one serious limitation: it can only be used for
53 storing integral types (bool, char, short, int, long and their unsigned
54 variants) or pointers (of any kind). An attempt to use with objects of
55 @c sizeof() greater than @c sizeof(long) will provoke a runtime assertion
56 failure, however declaring a wxArray of floats will not (on the machines
57 where @c "sizeof(float) <= sizeof(long)"), yet it will @b not work, please
58 use wxObjArray for storing floats and doubles.
60 wxSortedArray is a wxArray variant which should be used when searching in
61 the array is a frequently used operation. It requires you to define an
62 additional function for comparing two elements of the array element type
63 and always stores its items in the sorted order (according to this
64 function). Thus, its Index() function execution time is @c "O(log(N))"
65 instead of @c "O(N)" for the usual arrays but the Add() method is slower:
66 it is @c "O(log(N))" instead of constant time (neglecting time spent in
67 memory allocation routine). However, in a usual situation elements are
68 added to an array much less often than searched inside it, so wxSortedArray
69 may lead to huge performance improvements compared to wxArray. Finally, it
70 should be noticed that, as wxArray, wxSortedArray can be only used for
71 storing integral types or pointers.
73 wxObjArray class treats its elements like "objects". It may delete them
74 when they are removed from the array (invoking the correct destructor) and
75 copies them using the objects copy constructor. In order to implement this
76 behaviour the definition of the wxObjArray arrays is split in two parts:
77 first, you should declare the new wxObjArray class using the
78 WX_DECLARE_OBJARRAY() macro and then you must include the file defining the
79 implementation of template type: @<wx/arrimpl.cpp@> and define the array
80 class with the WX_DEFINE_OBJARRAY() macro from a point where the full (as
81 opposed to 'forward') declaration of the array elements class is in scope.
82 As it probably sounds very complicated here is an example:
85 #include <wx/dynarray.h>
87 // We must forward declare the array because it is used
88 // inside the class declaration.
92 // This defines two new types: ArrayOfDirectories and ArrayOfFiles which
93 // can be now used as shown below.
94 WX_DECLARE_OBJARRAY(MyDirectory, ArrayOfDirectories);
95 WX_DECLARE_OBJARRAY(MyFile, ArrayOfFiles);
100 ArrayOfDirectories m_subdirectories; // All subdirectories
101 ArrayOfFiles m_files; // All files in this directory
106 // Now that we have MyDirectory declaration in scope we may finish the
107 // definition of ArrayOfDirectories -- note that this expands into some C++
108 // code and so should only be compiled once (i.e., don't put this in the
109 // header, but into a source file or you will get linking errors)
110 #include <wx/arrimpl.cpp> // This is a magic incantation which must be done!
111 WX_DEFINE_OBJARRAY(ArrayOfDirectories);
116 It is not as elegant as writing this:
119 typedef std::vector<MyDirectory> ArrayOfDirectories;
122 But is not that complicated and allows the code to be compiled with any,
123 however dumb, C++ compiler in the world.
125 Remember to include @<wx/arrimpl.cpp@> just before each
126 WX_DEFINE_OBJARRAY() occurrence in your code, even if you have several in
129 Things are much simpler for wxArray and wxSortedArray however: it is enough
133 WX_DEFINE_ARRAY_INT(int, ArrayOfInts);
134 WX_DEFINE_SORTED_ARRAY_INT(int, ArrayOfSortedInts);
137 There is only one @c DEFINE macro and no need for separate @c DECLARE one.
138 For the arrays of the primitive types, the macros
139 @c 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
141 smaller type, e.g. shorts, in an array of larger one, e.g. @c ARRAY_INT,
142 does not work on all architectures!).
145 @section array_macros Macros for Template Array Definition
147 To use an array you must first define the array class. This is done with
148 the help of the macros in this section. The class of array elements must be
149 (at least) forward declared for WX_DEFINE_ARRAY(), WX_DEFINE_SORTED_ARRAY()
150 and WX_DECLARE_OBJARRAY() macros and must be fully declared before you use
151 WX_DEFINE_OBJARRAY() macro.
154 - WX_DEFINE_EXPORTED_ARRAY()
155 - WX_DEFINE_USER_EXPORTED_ARRAY()
156 - WX_DEFINE_SORTED_ARRAY()
157 - WX_DEFINE_SORTED_EXPORTED_ARRAY()
158 - WX_DEFINE_SORTED_USER_EXPORTED_ARRAY()
159 - WX_DECLARE_EXPORTED_OBJARRAY()
160 - WX_DECLARE_USER_EXPORTED_OBJARRAY()
161 - WX_DEFINE_OBJARRAY()
162 - WX_DEFINE_EXPORTED_OBJARRAY()
163 - WX_DEFINE_USER_EXPORTED_OBJARRAY()
165 To slightly complicate the matters even further, the operator "->" defined
166 by default for the array iterators by these macros only makes sense if the
167 array element type is not a pointer itself and, although it still works,
168 this provokes warnings from some compilers and to avoid them you should use
169 the @c _PTR versions of the macros above. For example, to define an array
170 of pointers to @c double you should use:
173 WX_DEFINE_ARRAY_PTR(double *, MyArrayOfDoublePointers);
176 Note that the above macros are generally only useful for wxObject types.
177 There are separate macros for declaring an array of a simple type, such as
180 The following simple types are supported:
186 To create an array of a simple type, simply append the type you want in
187 CAPS to the array definition.
189 For example, you'd use one of the following variants for an integer array:
191 - WX_DEFINE_ARRAY_INT()
192 - WX_DEFINE_EXPORTED_ARRAY_INT()
193 - WX_DEFINE_USER_EXPORTED_ARRAY_INT()
194 - WX_DEFINE_SORTED_ARRAY_INT()
195 - WX_DEFINE_SORTED_EXPORTED_ARRAY_INT()
196 - WX_DEFINE_SORTED_USER_EXPORTED_ARRAY_INT()
199 @section array_predef Predefined array types
201 wxWidgets defines the following dynamic array types:
208 To use them you don't need any macro; you just need to include @c dynarray.h.
212 @category{containers}
214 @see @ref overview_container, wxList<T>, wxVector<T>
216 template <typename T
>
221 @name Constructors and Destructors
223 Array classes are 100% C++ objects and as such they have the
224 appropriate copy constructors and assignment operators. Copying wxArray
225 just copies the elements but copying wxObjArray copies the arrays
226 items. However, for memory-efficiency sake, neither of these classes
227 has virtual destructor. It is not very important for wxArray which has
228 trivial destructor anyhow, but it does mean that you should avoid
229 deleting wxObjArray through a wxBaseArray pointer (as you would never
230 use wxBaseArray anyhow it shouldn't be a problem) and that you should
231 not derive your own classes from the array classes.
241 Default constructor initializes an empty array object.
246 There is no default constructor for wxSortedArray classes - you must
247 initialize it with a function to use for item comparison. It is a
248 function which is passed two arguments of type @c T where @c T is the
249 array element type and which should return a negative, zero or positive
250 value according to whether the first element passed to it is less than,
251 equal to or greater than the second one.
253 wxSortedArray(int (*)(T first
, T second
)compareFunction
);
256 Performs a shallow array copy (i.e.\ doesn't copy the objects pointed to
257 even if the source array contains the items of pointer type).
259 wxArray(const wxArray
& array
);
262 Performs a shallow array copy (i.e.\ doesn't copy the objects pointed to
263 even if the source array contains the items of pointer type).
265 wxSortedArray(const wxSortedArray
& array
);
268 Performs a deep copy (i.e.\ the array element are copied too).
270 wxObjArray(const wxObjArray
& array
);
273 Performs a shallow array copy (i.e.\ doesn't copy the objects pointed to
274 even if the source array contains the items of pointer type).
276 wxArray
& operator=(const wxArray
& array
);
279 Performs a shallow array copy (i.e.\ doesn't copy the objects pointed to
280 even if the source array contains the items of pointer type).
282 wxSortedArray
& operator=(const wxSortedArray
& array
);
285 Performs a deep copy (i.e.\ the array element are copied too).
287 wxObjArray
& operator=(const wxObjArray
& array
);
290 This destructor does not delete all the items owned by the array, you
291 may use the WX_CLEAR_ARRAY() macro for this.
296 This destructor does not delete all the items owned by the array, you
297 may use the WX_CLEAR_ARRAY() macro for this.
302 This destructor deletes all the items owned by the array.
310 @name Memory Management
312 Automatic array memory management is quite trivial: the array starts by
313 preallocating some minimal amount of memory (defined by
314 @c WX_ARRAY_DEFAULT_INITIAL_SIZE) and when further new items exhaust
315 already allocated memory it reallocates it adding 50% of the currently
316 allocated amount, but no more than some maximal number which is defined
317 by the @c ARRAY_MAXSIZE_INCREMENT constant. Of course, this may lead to
318 some memory being wasted (@c ARRAY_MAXSIZE_INCREMENT in the worst case,
319 i.e. 4Kb in the current implementation), so the Shrink() function is
320 provided to deallocate the extra memory. The Alloc() function can also
321 be quite useful if you know in advance how many items you are going to
322 put in the array and will prevent the array code from reallocating the
323 memory more times than needed.
328 Preallocates memory for a given number of array elements. It is worth
329 calling when the number of items which are going to be added to the
330 array is known in advance because it will save unneeded memory
331 reallocation. If the array already has enough memory for the given
332 number of items, nothing happens. In any case, the existing contents of
333 the array is not modified.
335 void Alloc(size_t count
);
338 Frees all memory unused by the array. If the program knows that no new
339 items will be added to the array it may call Shrink() to reduce its
340 memory usage. However, if a new item is added to the array, some extra
341 memory will be allocated again.
349 @name Number of Elements and Simple Item Access
351 Functions in this section return the total number of array elements and
352 allow to retrieve them - possibly using just the C array indexing []
353 operator which does exactly the same as the Item() method.
358 Return the number of items in the array.
360 size_t GetCount() const;
363 Returns @true if the array is empty, @false otherwise.
365 bool IsEmpty() const;
368 Returns the item at the given position in the array. If @a index is out
369 of bounds, an assert failure is raised in the debug builds but nothing
370 special is done in the release build.
372 The returned value is of type "reference to the array element type" for
373 all of the array classes.
375 T
& Item(size_t index
) const;
378 Returns the last element in the array, i.e.\ is the same as calling
379 "Item(GetCount() - 1)". An assert failure is raised in the debug mode
380 if the array is empty.
382 The returned value is of type "reference to the array element type" for
383 all of the array classes.
396 Appends the given number of @a copies of the @a item to the array
397 consisting of the elements of type @c T.
399 This version is used with wxArray.
401 You may also use WX_APPEND_ARRAY() macro to append all elements of one
402 array to another one but it is more efficient to use the @a copies
403 parameter and modify the elements in place later if you plan to append
406 void Add(T item
, size_t copies
= 1);
409 Appends the @a item to the array consisting of the elements of type
412 This version is used with wxSortedArray, returning the index where
418 Appends the @a item to the array consisting of the elements of type
421 This version is used with wxObjArray. The array will take ownership of
422 the @a item, deleting it when the item is deleted from the array. Note
423 that you cannot append more than one pointer as reusing it would lead
424 to deleting it twice (or more) resulting in a crash.
426 You may also use WX_APPEND_ARRAY() macro to append all elements of one
427 array to another one but it is more efficient to use the @a copies
428 parameter and modify the elements in place later if you plan to append
434 Appends the given number of @a copies of the @a item to the array
435 consisting of the elements of type @c T.
437 This version is used with wxObjArray. The array will make a copy of the
438 item and will not take ownership of the original item.
440 You may also use WX_APPEND_ARRAY() macro to append all elements of one
441 array to another one but it is more efficient to use the @a copies
442 parameter and modify the elements in place later if you plan to append
445 void Add(T
& item
, size_t copies
= 1);
448 Inserts the given @a item into the array in the specified @e index
451 Be aware that you will set out the order of the array if you give a
454 This function is useful in conjunction with IndexForInsert() for a
455 common operation of "insert only if not found".
457 void AddAt(T item
, size_t index
);
460 Insert the given number of @a copies of the @a item into the array
461 before the existing item @a n - thus, @e Insert(something, 0u) will
462 insert an item in such way that it will become the first array element.
464 wxSortedArray doesn't have this function because inserting in wrong
465 place would break its sorted condition.
467 Please see Add() for an explanation of the differences between the
468 overloaded versions of this function.
470 void Insert(T item
, size_t n
, size_t copies
= 1);
473 Insert the @a item into the array before the existing item @a n - thus,
474 @e Insert(something, 0u) will insert an item in such way that it will
475 become the first array element.
477 wxSortedArray doesn't have this function because inserting in wrong
478 place would break its sorted condition.
480 Please see Add() for an explanation of the differences between the
481 overloaded versions of this function.
483 void Insert(T
* item
, size_t n
);
486 Insert the given number of @a copies of the @a item into the array
487 before the existing item @a n - thus, @e Insert(something, 0u) will
488 insert an item in such way that it will become the first array element.
490 wxSortedArray doesn't have this function because inserting in wrong
491 place would break its sorted condition.
493 Please see Add() for an explanation of the differences between the
494 overloaded versions of this function.
496 void Insert(T
& item
, size_t n
, size_t copies
= 1);
499 This function ensures that the number of array elements is at least
500 @a count. If the array has already @a count or more items, nothing is
501 done. Otherwise, @a count - GetCount() elements are added and
502 initialized to the value @a defval.
506 void SetCount(size_t count
, T defval
= T(0));
517 This function does the same as Empty() and additionally frees the
518 memory allocated to the array.
523 Removes the element from the array, but unlike Remove(), it doesn't
524 delete it. The function returns the pointer to the removed element.
526 T
* Detach(size_t index
);
529 Empties the array. For wxObjArray classes, this destroys all of the
530 array elements. For wxArray and wxSortedArray this does nothing except
531 marking the array of being empty - this function does not free the
532 allocated memory, use Clear() for this.
537 Removes an element from the array by value: the first item of the array
538 equal to @a item is removed, an assert failure will result from an
539 attempt to remove an item which doesn't exist in the array.
541 When an element is removed from wxObjArray it is deleted by the array -
542 use Detach() if you don't want this to happen. On the other hand, when
543 an object is removed from a wxArray nothing happens - you should delete
544 it manually if required:
552 See also WX_CLEAR_ARRAY() macro which deletes all elements of a wxArray
553 (supposed to contain pointers).
555 Notice that for sorted arrays this method uses binary search to find
556 the item so it doesn't necessarily remove the first matching item, but
557 the first one found by the binary search.
564 Removes @a count elements starting at @a index from the array. When an
565 element is removed from wxObjArray it is deleted by the array - use
566 Detach() if you don't want this to happen. On the other hand, when an
567 object is removed from a wxArray nothing happens - you should delete it
568 manually if required:
576 See also WX_CLEAR_ARRAY() macro which deletes all elements of a wxArray
577 (supposed to contain pointers).
579 void RemoveAt(size_t index
, size_t count
= 1);
585 @name Searching and Sorting
590 This version of Index() is for wxArray and wxObjArray only.
592 Searches the element in the array, starting from either beginning or
593 the end depending on the value of @a searchFromEnd parameter.
594 @c wxNOT_FOUND is returned if the element is not found, otherwise the
595 index of the element is returned.
597 @note Even for wxObjArray classes, the operator "==" of the elements in
598 the array is @b not used by this function. It searches exactly
599 the given element in the array and so will only succeed if this
600 element had been previously added to the array, but fail even if
601 another, identical, element is in the array.
603 int Index(T
& item
, bool searchFromEnd
= false) const;
606 This version of Index() is for wxSortedArray only.
608 Searches for the element in the array, using binary search.
610 @c wxNOT_FOUND is returned if the element is not found, otherwise the
611 index of the element is returned.
613 int Index(T
& item
) const;
616 Search for a place to insert @a item into the sorted array (binary
617 search). The index returned is just before the first existing item that
618 is greater or equal (according to the compare function) to the given
621 You have to do extra work to know if the @a item already exists in
624 This function is useful in conjunction with AddAt() for a common
625 operation of "insert only if not found".
627 size_t IndexForInsert(T item
) const;
630 The notation @c "CMPFUNCT<T>" should be read as if we had the following
634 template int CMPFUNC(T *first, T *second);
637 Where @e T is the type of the array elements. I.e. it is a function
638 returning @e int which is passed two arguments of type @e T*.
640 Sorts the array using the specified compare function: this function
641 should return a negative, zero or positive value according to whether
642 the first element passed to it is less than, equal to or greater than
645 wxSortedArray doesn't have this function because it is always sorted.
647 void Sort(CMPFUNC
<T
> compareFunction
);
654 This macro may be used to append all elements of the @a wxArray_arrayToBeAppended
655 array to the @a wxArray_arrayToModify. The two arrays must be of the same type.
657 #define WX_APPEND_ARRAY(wxArray_arrayToModify, wxArray_arrayToBeAppended)
660 This macro may be used to delete all elements of the array before emptying
661 it. It cannot be used with wxObjArrays - but they will delete their
662 elements anyway when you call Empty().
664 #define WX_CLEAR_ARRAY(wxArray_arrayToBeCleared)
668 This macro declares a new object array class named @a name and containing
669 the elements of type @e T.
671 An exported array is used when compiling wxWidgets as a DLL under Windows
672 and the array needs to be visible outside the DLL. An user exported array
673 needed for exporting an array from a user DLL.
679 WX_DECLARE_OBJARRAY(MyClass, wxArrayOfMyClass); // note: not "MyClass *"!
682 You must use WX_DEFINE_OBJARRAY() macro to define the array class,
683 otherwise you would get link errors.
685 #define WX_DECLARE_OBJARRAY(T, name)
686 #define WX_DECLARE_EXPORTED_OBJARRAY(T, name)
687 #define WX_DECLARE_USER_EXPORTED_OBJARRAY(T, name)
692 This macro defines a new array class named @a name and containing the
693 elements of type @a T.
695 An exported array is used when compiling wxWidgets as a DLL under Windows
696 and the array needs to be visible outside the DLL. An user exported array
697 needed for exporting an array from a user DLL.
702 WX_DEFINE_ARRAY_INT(int, MyArrayInt);
705 WX_DEFINE_ARRAY(MyClass *, ArrayOfMyClass);
708 Note that wxWidgets predefines the following standard array classes:
709 @b wxArrayInt, @b wxArrayLong, @b wxArrayShort, @b wxArrayDouble,
712 #define WX_DEFINE_ARRAY(T, name)
713 #define WX_DEFINE_EXPORTED_ARRAY(T, name)
714 #define WX_DEFINE_USER_EXPORTED_ARRAY(T, name, exportspec)
719 This macro defines the methods of the array class @a name not defined by
720 the WX_DECLARE_OBJARRAY() macro. You must include the file
721 @<wx/arrimpl.cpp@> before using this macro and you must have the full
722 declaration of the class of array elements in scope! If you forget to do
723 the first, the error will be caught by the compiler, but, unfortunately,
724 many compilers will not give any warnings if you forget to do the second -
725 but the objects of the class will not be copied correctly and their real
726 destructor will not be called.
728 An exported array is used when compiling wxWidgets as a DLL under Windows
729 and the array needs to be visible outside the DLL. An user exported array
730 needed for exporting an array from a user DLL.
735 // first declare the class!
739 MyClass(const MyClass&);
746 #include <wx/arrimpl.cpp>
747 WX_DEFINE_OBJARRAY(wxArrayOfMyClass);
750 #define WX_DEFINE_OBJARRAY(name)
751 #define WX_DEFINE_EXPORTED_OBJARRAY(name)
752 #define WX_DEFINE_USER_EXPORTED_OBJARRAY(name)
757 This macro defines a new sorted array class named @a name and containing
758 the elements of type @e T.
760 An exported array is used when compiling wxWidgets as a DLL under Windows
761 and the array needs to be visible outside the DLL. An user exported array
762 needed for exporting an array from a user DLL.
767 WX_DEFINE_SORTED_ARRAY_INT(int, MySortedArrayInt);
770 WX_DEFINE_SORTED_ARRAY(MyClass *, ArrayOfMyClass);
773 You will have to initialize the objects of this class by passing a
774 comparison function to the array object constructor like this:
777 int CompareInts(int n1, int n2)
782 MySortedArrayInt sorted(CompareInts);
784 int CompareMyClassObjects(MyClass *item1, MyClass *item2)
786 // sort the items by their address...
787 return Stricmp(item1->GetAddress(), item2->GetAddress());
790 ArrayOfMyClass another(CompareMyClassObjects);
793 #define WX_DEFINE_SORTED_ARRAY(T, name)
794 #define WX_DEFINE_SORTED_EXPORTED_ARRAY(T, name)
795 #define WX_DEFINE_SORTED_USER_EXPORTED_ARRAY(T, name)
799 This macro may be used to prepend all elements of the @a wxArray_arrayToBePrepended
800 array to the @a wxArray_arrayToModify. The two arrays must be of the same type.
802 #define WX_PREPEND_ARRAY(wxArray_arrayToModify, wxArray_arrayToBePrepended)
806 Predefined specialization of wxArray<T> for standard types.
808 typedef wxArray
<int> wxArrayInt
;
809 typedef wxArray
<long> wxArrayLong
;
810 typedef wxArray
<short> wxArrayShort
;
811 typedef wxArray
<double> wxArrayDouble
;
812 typedef wxArray
<void*> wxArrayPtrVoid
;