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/////////////////////////////////////////////////////////////////////////////
// Name: dynarray.h
// Purpose: interface of wxArray<T>
// Author: wxWidgets team
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
/**
This section describes the so called @e "dynamic arrays". This is a C
array-like type safe data structure i.e. the member access time is constant
(and not linear according to the number of container elements as for linked
lists). However, these arrays are dynamic in the sense that they will
automatically allocate more memory if there is not enough of it for adding
a new element. They also perform range checking on the index values but in
debug mode only, so please be sure to compile your application in debug
mode to use it (see @ref overview_debugging for details). So, unlike the
arrays in some other languages, attempt to access an element beyond the
arrays bound doesn't automatically expand the array but provokes an
assertion failure instead in debug build and does nothing (except possibly
crashing your program) in the release build.
The array classes were designed to be reasonably efficient, both in terms
of run-time speed and memory consumption and the executable size. The speed
of array item access is, of course, constant (independent of the number of
elements) making them much more efficient than linked lists (wxList).
Adding items to the arrays is also implemented in more or less constant
time, but the price is preallocating the memory in advance. In the
"memory management" function section, you may find some useful hints about
optimizing wxArray memory usage. As for executable size, all wxArray
functions are inline, so they do not take @e any space at all.
wxWidgets has three different kinds of array. All of them derive from
wxBaseArray class which works with untyped data and cannot be used
directly. The standard macros WX_DEFINE_ARRAY(), WX_DEFINE_SORTED_ARRAY()
and WX_DEFINE_OBJARRAY() are used to define a new class deriving from it.
The classes declared will be called in this documentation wxArray,
wxSortedArray and wxObjArray but you should keep in mind that no classes
with such names actually exist, each time you use one of the
WX_DEFINE_XXXARRAY() macros, you define a class with a new name. In fact,
these names are "template" names and each usage of one of the macros
mentioned above creates a template specialization for the given element
type.
wxArray is suitable for storing integer types and pointers which it does
not treat as objects in any way, i.e. the element pointed to by the pointer
is not deleted when the element is removed from the array. It should be
noted that all of wxArray's functions are inline, so it costs strictly
nothing to define as many array types as you want (either in terms of the
executable size or the speed) as long as at least one of them is defined
and this is always the case because wxArrays are used by wxWidgets
internally. This class has one serious limitation: it can only be used for
storing integral types (bool, char, short, int, long and their unsigned
variants) or pointers (of any kind). An attempt to use with objects of
@c sizeof() greater than @c sizeof(long) will provoke a runtime assertion
failure, however declaring a wxArray of floats will not (on the machines
where @c "sizeof(float) <= sizeof(long)"), yet it will @b not work, please
use wxObjArray for storing floats and doubles.
wxSortedArray is a wxArray variant which should be used when searching in
the array is a frequently used operation. It requires you to define an
additional function for comparing two elements of the array element type
and always stores its items in the sorted order (according to this
function). Thus, its Index() function execution time is @c "O(log(N))"
instead of @c "O(N)" for the usual arrays but the Add() method is slower:
it is @c "O(log(N))" instead of constant time (neglecting time spent in
memory allocation routine). However, in a usual situation elements are
added to an array much less often than searched inside it, so wxSortedArray
may lead to huge performance improvements compared to wxArray. Finally, it
should be noticed that, as wxArray, wxSortedArray can be only used for
storing integral types or pointers.
wxObjArray class treats its elements like "objects". It may delete them
when they are removed from the array (invoking the correct destructor) and
copies them using the objects copy constructor. In order to implement this
behaviour the definition of the wxObjArray arrays is split in two parts:
first, you should declare the new wxObjArray class using the
WX_DECLARE_OBJARRAY() macro and then you must include the file defining the
implementation of template type: @<wx/arrimpl.cpp@> and define the array
class with the WX_DEFINE_OBJARRAY() macro from a point where the full (as
opposed to 'forward') declaration of the array elements class is in scope.
As it probably sounds very complicated here is an example:
@code
#include <wx/dynarray.h>
// We must forward declare the array because it is used
// inside the class declaration.
class MyDirectory;
class MyFile;
// This defines two new types: ArrayOfDirectories and ArrayOfFiles which
// can be now used as shown below.
WX_DECLARE_OBJARRAY(MyDirectory, ArrayOfDirectories);
WX_DECLARE_OBJARRAY(MyFile, ArrayOfFiles);
class MyDirectory
{
// ...
ArrayOfDirectories m_subdirectories; // All subdirectories
ArrayOfFiles m_files; // All files in this directory
};
// ...
// Now that we have MyDirectory declaration in scope we may finish the
// definition of ArrayOfDirectories -- note that this expands into some C++
// code and so should only be compiled once (i.e., don't put this in the
// header, but into a source file or you will get linking errors)
#include <wx/arrimpl.cpp> // This is a magic incantation which must be done!
WX_DEFINE_OBJARRAY(ArrayOfDirectories);
// that's all!
@endcode
It is not as elegant as writing this:
@code
typedef std::vector<MyDirectory> ArrayOfDirectories;
@endcode
But is not that complicated and allows the code to be compiled with any,
however dumb, C++ compiler in the world.
Remember to include @<wx/arrimpl.cpp@> just before each
WX_DEFINE_OBJARRAY() occurrence in your code, even if you have several in
the same file.
Things are much simpler for wxArray and wxSortedArray however: it is enough
just to write:
@code
WX_DEFINE_ARRAY_INT(int, ArrayOfInts);
WX_DEFINE_SORTED_ARRAY_INT(int, ArrayOfSortedInts);
@endcode
There is only one @c DEFINE macro and no need for separate @c DECLARE one.
For the arrays of the primitive types, the macros
@c WX_DEFINE_ARRAY_CHAR/SHORT/INT/SIZE_T/LONG/DOUBLE should be used
depending on the sizeof of the values (notice that storing values of
smaller type, e.g. shorts, in an array of larger one, e.g. @c ARRAY_INT,
does not work on all architectures!).
@section array_macros Macros for Template Array Definition
To use an array you must first define the array class. This is done with
the help of the macros in this section. The class of array elements must be
(at least) forward declared for WX_DEFINE_ARRAY(), WX_DEFINE_SORTED_ARRAY()
and WX_DECLARE_OBJARRAY() macros and must be fully declared before you use
WX_DEFINE_OBJARRAY() macro.
- WX_DEFINE_ARRAY()
- WX_DEFINE_EXPORTED_ARRAY()
- WX_DEFINE_USER_EXPORTED_ARRAY()
- WX_DEFINE_SORTED_ARRAY()
- WX_DEFINE_SORTED_EXPORTED_ARRAY()
- WX_DEFINE_SORTED_USER_EXPORTED_ARRAY()
- WX_DECLARE_EXPORTED_OBJARRAY()
- WX_DECLARE_USER_EXPORTED_OBJARRAY()
- WX_DEFINE_OBJARRAY()
- WX_DEFINE_EXPORTED_OBJARRAY()
- WX_DEFINE_USER_EXPORTED_OBJARRAY()
To slightly complicate the matters even further, the operator "->" defined
by default for the array iterators by these macros only makes sense if the
array element type is not a pointer itself and, although it still works,
this provokes warnings from some compilers and to avoid them you should use
the @c _PTR versions of the macros above. For example, to define an array
of pointers to @c double you should use:
@code
WX_DEFINE_ARRAY_PTR(double *, MyArrayOfDoublePointers);
@endcode
Note that the above macros are generally only useful for wxObject types.
There are separate macros for declaring an array of a simple type, such as
an int.
The following simple types are supported:
- @c int
- @c long
- @c size_t
- @c double
To create an array of a simple type, simply append the type you want in
CAPS to the array definition.
For example, you'd use one of the following variants for an integer array:
- WX_DEFINE_ARRAY_INT()
- WX_DEFINE_EXPORTED_ARRAY_INT()
- WX_DEFINE_USER_EXPORTED_ARRAY_INT()
- WX_DEFINE_SORTED_ARRAY_INT()
- WX_DEFINE_SORTED_EXPORTED_ARRAY_INT()
- WX_DEFINE_SORTED_USER_EXPORTED_ARRAY_INT()
@section array_predef Predefined array types
wxWidgets defines the following dynamic array types:
- ::wxArrayShort
- ::wxArrayInt
- ::wxArrayDouble
- ::wxArrayLong
- ::wxArrayPtrVoid
To use them you don't need any macro; you just need to include @c dynarray.h.
@library{wxbase}
@category{containers}
@see @ref overview_container, wxList<T>, wxVector<T>
*/
template <typename T>
class wxArray<T>
{
public:
/**
@name Constructors and Destructors
Array classes are 100% C++ objects and as such they have the
appropriate copy constructors and assignment operators. Copying wxArray
just copies the elements but copying wxObjArray copies the arrays
items. However, for memory-efficiency sake, neither of these classes
has virtual destructor. It is not very important for wxArray which has
trivial destructor anyhow, but it does mean that you should avoid
deleting wxObjArray through a wxBaseArray pointer (as you would never
use wxBaseArray anyhow it shouldn't be a problem) and that you should
not derive your own classes from the array classes.
*/
//@{
/**
Default constructor.
*/
wxArray();
/**
Default constructor initializes an empty array object.
*/
wxObjArray();
/**
There is no default constructor for wxSortedArray classes - you must
initialize it with a function to use for item comparison. It is a
function which is passed two arguments of type @c T where @c T is the
array element type and which should return a negative, zero or positive
value according to whether the first element passed to it is less than,
equal to or greater than the second one.
*/
wxSortedArray(int (*)(T first, T second)compareFunction);
/**
Performs a shallow array copy (i.e.\ doesn't copy the objects pointed to
even if the source array contains the items of pointer type).
*/
wxArray(const wxArray& array);
/**
Performs a shallow array copy (i.e.\ doesn't copy the objects pointed to
even if the source array contains the items of pointer type).
*/
wxSortedArray(const wxSortedArray& array);
/**
Performs a deep copy (i.e.\ the array element are copied too).
*/
wxObjArray(const wxObjArray& array);
/**
Performs a shallow array copy (i.e.\ doesn't copy the objects pointed to
even if the source array contains the items of pointer type).
*/
wxArray& operator=(const wxArray& array);
/**
Performs a shallow array copy (i.e.\ doesn't copy the objects pointed to
even if the source array contains the items of pointer type).
*/
wxSortedArray& operator=(const wxSortedArray& array);
/**
Performs a deep copy (i.e.\ the array element are copied too).
*/
wxObjArray& operator=(const wxObjArray& array);
/**
This destructor does not delete all the items owned by the array, you
may use the WX_CLEAR_ARRAY() macro for this.
*/
~wxArray();
/**
This destructor does not delete all the items owned by the array, you
may use the WX_CLEAR_ARRAY() macro for this.
*/
~wxSortedArray();
/**
This destructor deletes all the items owned by the array.
*/
~wxObjArray();
//@}
/**
@name Memory Management
Automatic array memory management is quite trivial: the array starts by
preallocating some minimal amount of memory (defined by
@c WX_ARRAY_DEFAULT_INITIAL_SIZE) and when further new items exhaust
already allocated memory it reallocates it adding 50% of the currently
allocated amount, but no more than some maximal number which is defined
by the @c ARRAY_MAXSIZE_INCREMENT constant. Of course, this may lead to
some memory being wasted (@c ARRAY_MAXSIZE_INCREMENT in the worst case,
i.e. 4Kb in the current implementation), so the Shrink() function is
provided to deallocate the extra memory. The Alloc() function can also
be quite useful if you know in advance how many items you are going to
put in the array and will prevent the array code from reallocating the
memory more times than needed.
*/
//@{
/**
Preallocates memory for a given number of array elements. It is worth
calling when the number of items which are going to be added to the
array is known in advance because it will save unneeded memory
reallocation. If the array already has enough memory for the given
number of items, nothing happens. In any case, the existing contents of
the array is not modified.
*/
void Alloc(size_t count);
/**
Frees all memory unused by the array. If the program knows that no new
items will be added to the array it may call Shrink() to reduce its
memory usage. However, if a new item is added to the array, some extra
memory will be allocated again.
*/
void Shrink();
//@}
/**
@name Number of Elements and Simple Item Access
Functions in this section return the total number of array elements and
allow to retrieve them - possibly using just the C array indexing []
operator which does exactly the same as the Item() method.
*/
//@{
/**
Return the number of items in the array.
*/
size_t GetCount() const;
/**
Returns @true if the array is empty, @false otherwise.
*/
bool IsEmpty() const;
/**
Returns the item at the given position in the array. If @a index is out
of bounds, an assert failure is raised in the debug builds but nothing
special is done in the release build.
The returned value is of type "reference to the array element type" for
all of the array classes.
*/
T& Item(size_t index) const;
/**
Returns the last element in the array, i.e.\ is the same as calling
"Item(GetCount() - 1)". An assert failure is raised in the debug mode
if the array is empty.
The returned value is of type "reference to the array element type" for
all of the array classes.
*/
T& Last() const;
//@}
/**
@name Adding Items
*/
//@{
/**
Appends the given number of @a copies of the @a item to the array
consisting of the elements of type @c T.
This version is used with wxArray.
You may also use WX_APPEND_ARRAY() macro to append all elements of one
array to another one but it is more efficient to use the @a copies
parameter and modify the elements in place later if you plan to append
a lot of items.
*/
void Add(T item, size_t copies = 1);
/**
Appends the @a item to the array consisting of the elements of type
@c T.
This version is used with wxSortedArray, returning the index where
@a item is stored.
*/
size_t Add(T item);
/**
Appends the @a item to the array consisting of the elements of type
@c T.
This version is used with wxObjArray. The array will take ownership of
the @a item, deleting it when the item is deleted from the array. Note
that you cannot append more than one pointer as reusing it would lead
to deleting it twice (or more) resulting in a crash.
You may also use WX_APPEND_ARRAY() macro to append all elements of one
array to another one but it is more efficient to use the @a copies
parameter and modify the elements in place later if you plan to append
a lot of items.
*/
void Add(T* item);
/**
Appends the given number of @a copies of the @a item to the array
consisting of the elements of type @c T.
This version is used with wxObjArray. The array will make a copy of the
item and will not take ownership of the original item.
You may also use WX_APPEND_ARRAY() macro to append all elements of one
array to another one but it is more efficient to use the @a copies
parameter and modify the elements in place later if you plan to append
a lot of items.
*/
void Add(T& item, size_t copies = 1);
/**
Inserts the given @a item into the array in the specified @e index
position.
Be aware that you will set out the order of the array if you give a
wrong position.
This function is useful in conjunction with IndexForInsert() for a
common operation of "insert only if not found".
*/
void AddAt(T item, size_t index);
/**
Insert the given number of @a copies of the @a item into the array
before the existing item @a n - thus, @e Insert(something, 0u) will
insert an item in such way that it will become the first array element.
wxSortedArray doesn't have this function because inserting in wrong
place would break its sorted condition.
Please see Add() for an explanation of the differences between the
overloaded versions of this function.
*/
void Insert(T item, size_t n, size_t copies = 1);
/**
Insert the @a item into the array before the existing item @a n - thus,
@e Insert(something, 0u) will insert an item in such way that it will
become the first array element.
wxSortedArray doesn't have this function because inserting in wrong
place would break its sorted condition.
Please see Add() for an explanation of the differences between the
overloaded versions of this function.
*/
void Insert(T* item, size_t n);
/**
Insert the given number of @a copies of the @a item into the array
before the existing item @a n - thus, @e Insert(something, 0u) will
insert an item in such way that it will become the first array element.
wxSortedArray doesn't have this function because inserting in wrong
place would break its sorted condition.
Please see Add() for an explanation of the differences between the
overloaded versions of this function.
*/
void Insert(T& item, size_t n, size_t copies = 1);
/**
This function ensures that the number of array elements is at least
@a count. If the array has already @a count or more items, nothing is
done. Otherwise, @a count - GetCount() elements are added and
initialized to the value @a defval.
@see GetCount()
*/
void SetCount(size_t count, T defval = T(0));
//@}
/**
@name Removing Items
*/
//@{
/**
This function does the same as Empty() and additionally frees the
memory allocated to the array.
*/
void Clear();
/**
Removes the element from the array, but unlike Remove(), it doesn't
delete it. The function returns the pointer to the removed element.
*/
T* Detach(size_t index);
/**
Empties the array. For wxObjArray classes, this destroys all of the
array elements. For wxArray and wxSortedArray this does nothing except
marking the array of being empty - this function does not free the
allocated memory, use Clear() for this.
*/
void Empty();
/**
Removes an element from the array by value: the first item of the array
equal to @a item is removed, an assert failure will result from an
attempt to remove an item which doesn't exist in the array.
When an element is removed from wxObjArray it is deleted by the array -
use Detach() if you don't want this to happen. On the other hand, when
an object is removed from a wxArray nothing happens - you should delete
it manually if required:
@code
T *item = array[n];
array.Remove(item);
delete item;
@endcode
See also WX_CLEAR_ARRAY() macro which deletes all elements of a wxArray
(supposed to contain pointers).
Notice that for sorted arrays this method uses binary search to find
the item so it doesn't necessarily remove the first matching item, but
the first one found by the binary search.
@see RemoveAt()
*/
void Remove(T item);
/**
Removes @a count elements starting at @a index from the array. When an
element is removed from wxObjArray it is deleted by the array - use
Detach() if you don't want this to happen. On the other hand, when an
object is removed from a wxArray nothing happens - you should delete it
manually if required:
@code
T *item = array[n];
delete item;
array.RemoveAt(n);
@endcode
See also WX_CLEAR_ARRAY() macro which deletes all elements of a wxArray
(supposed to contain pointers).
*/
void RemoveAt(size_t index, size_t count = 1);
//@}
/**
@name Searching and Sorting
*/
//@{
/**
This version of Index() is for wxArray and wxObjArray only.
Searches the element in the array, starting from either beginning or
the end depending on the value of @a searchFromEnd parameter.
@c wxNOT_FOUND is returned if the element is not found, otherwise the
index of the element is returned.
@note Even for wxObjArray classes, the operator "==" of the elements in
the array is @b not used by this function. It searches exactly
the given element in the array and so will only succeed if this
element had been previously added to the array, but fail even if
another, identical, element is in the array.
*/
int Index(T& item, bool searchFromEnd = false) const;
/**
This version of Index() is for wxSortedArray only.
Searches for the element in the array, using binary search.
@c wxNOT_FOUND is returned if the element is not found, otherwise the
index of the element is returned.
*/
int Index(T& item) const;
/**
Search for a place to insert @a item into the sorted array (binary
search). The index returned is just before the first existing item that
is greater or equal (according to the compare function) to the given
@a item.
You have to do extra work to know if the @a item already exists in
array.
This function is useful in conjunction with AddAt() for a common
operation of "insert only if not found".
*/
size_t IndexForInsert(T item) const;
/**
The notation @c "CMPFUNCT<T>" should be read as if we had the following
declaration:
@code
template int CMPFUNC(T *first, T *second);
@endcode
Where @e T is the type of the array elements. I.e. it is a function
returning @e int which is passed two arguments of type @e T*.
Sorts the array using the specified compare function: this function
should return a negative, zero or positive value according to whether
the first element passed to it is less than, equal to or greater than
the second one.
wxSortedArray doesn't have this function because it is always sorted.
*/
void Sort(CMPFUNC<T> compareFunction);
//@}
};
/**
This macro may be used to append all elements of the @a wxArray_arrayToBeAppended
array to the @a wxArray_arrayToModify. The two arrays must be of the same type.
*/
#define WX_APPEND_ARRAY(wxArray_arrayToModify, wxArray_arrayToBeAppended)
/**
This macro may be used to delete all elements of the array before emptying
it. It cannot be used with wxObjArrays - but they will delete their
elements anyway when you call Empty().
*/
#define WX_CLEAR_ARRAY(wxArray_arrayToBeCleared)
//@{
/**
This macro declares a new object array class named @a name and containing
the elements of type @e T.
An exported array is used when compiling wxWidgets as a DLL under Windows
and the array needs to be visible outside the DLL. An user exported array
needed for exporting an array from a user DLL.
Example:
@code
class MyClass;
WX_DECLARE_OBJARRAY(MyClass, wxArrayOfMyClass); // note: not "MyClass *"!
@endcode
You must use WX_DEFINE_OBJARRAY() macro to define the array class,
otherwise you would get link errors.
*/
#define WX_DECLARE_OBJARRAY(T, name)
#define WX_DECLARE_EXPORTED_OBJARRAY(T, name)
#define WX_DECLARE_USER_EXPORTED_OBJARRAY(T, name, expmode)
//@}
//@{
/**
This macro defines a new array class named @a name and containing the
elements of type @a T.
An exported array is used when compiling wxWidgets as a DLL under Windows
and the array needs to be visible outside the DLL. An user exported array
needed for exporting an array from a user DLL.
Example:
@code
WX_DEFINE_ARRAY_INT(int, MyArrayInt);
class MyClass;
WX_DEFINE_ARRAY(MyClass *, ArrayOfMyClass);
@endcode
Note that wxWidgets predefines the following standard array classes:
@b wxArrayInt, @b wxArrayLong, @b wxArrayShort, @b wxArrayDouble,
@b wxArrayPtrVoid.
*/
#define WX_DEFINE_ARRAY(T, name)
#define WX_DEFINE_EXPORTED_ARRAY(T, name)
#define WX_DEFINE_USER_EXPORTED_ARRAY(T, name, exportspec)
//@}
//@{
/**
This macro defines the methods of the array class @a name not defined by
the WX_DECLARE_OBJARRAY() macro. You must include the file
@<wx/arrimpl.cpp@> before using this macro and you must have the full
declaration of the class of array elements in scope! If you forget to do
the first, the error will be caught by the compiler, but, unfortunately,
many compilers will not give any warnings if you forget to do the second -
but the objects of the class will not be copied correctly and their real
destructor will not be called.
An exported array is used when compiling wxWidgets as a DLL under Windows
and the array needs to be visible outside the DLL. An user exported array
needed for exporting an array from a user DLL.
Example of usage:
@code
// first declare the class!
class MyClass
{
public:
MyClass(const MyClass&);
// ...
virtual ~MyClass();
};
#include <wx/arrimpl.cpp>
WX_DEFINE_OBJARRAY(wxArrayOfMyClass);
@endcode
*/
#define WX_DEFINE_OBJARRAY(name)
#define WX_DEFINE_EXPORTED_OBJARRAY(name)
#define WX_DEFINE_USER_EXPORTED_OBJARRAY(name)
//@}
//@{
/**
This macro defines a new sorted array class named @a name and containing
the elements of type @e T.
An exported array is used when compiling wxWidgets as a DLL under Windows
and the array needs to be visible outside the DLL. An user exported array
needed for exporting an array from a user DLL.
Example:
@code
WX_DEFINE_SORTED_ARRAY_INT(int, MySortedArrayInt);
class MyClass;
WX_DEFINE_SORTED_ARRAY(MyClass *, ArrayOfMyClass);
@endcode
You will have to initialize the objects of this class by passing a
comparison function to the array object constructor like this:
@code
int CompareInts(int n1, int n2)
{
return n1 - n2;
}
MySortedArrayInt sorted(CompareInts);
int CompareMyClassObjects(MyClass *item1, MyClass *item2)
{
// sort the items by their address...
return Stricmp(item1->GetAddress(), item2->GetAddress());
}
ArrayOfMyClass another(CompareMyClassObjects);
@endcode
*/
#define WX_DEFINE_SORTED_ARRAY(T, name)
#define WX_DEFINE_SORTED_EXPORTED_ARRAY(T, name)
#define WX_DEFINE_SORTED_USER_EXPORTED_ARRAY(T, name, expmode)
//@}
/**
This macro may be used to prepend all elements of the @a wxArray_arrayToBePrepended
array to the @a wxArray_arrayToModify. The two arrays must be of the same type.
*/
#define WX_PREPEND_ARRAY(wxArray_arrayToModify, wxArray_arrayToBePrepended)
//@{
/**
Predefined specialization of wxArray<T> for standard types.
*/
typedef wxArray<int> wxArrayInt;
typedef wxArray<long> wxArrayLong;
typedef wxArray<short> wxArrayShort;
typedef wxArray<double> wxArrayDouble;
typedef wxArray<void*> wxArrayPtrVoid;
//@}