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 {\it any space at all}.
-wxWindows has three different kinds of array. All of them derive from
+wxWidgets has three different kinds of array. All of them derive from
wxBaseArray class which works with untyped data and can not 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
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 wxWindows internally.
+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 sizeof() greater than sizeof(long) will provoke a
+runtime assertion failure, however declaring a wxArray of floats will not (on
+the machines where sizeof(float) <= sizeof(long)), yet it will {\bf not} work,
+please use wxObjArray for storing floats and doubles (NB: a more efficient
+wxArrayDouble class is scheduled for the next release of wxWidgets).
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, it's
+its items in the sorted order (according to this function). Thus, it is
\helpref{Index()}{wxarrayindex} function execution time is $O(log(N))$ instead of
$O(N)$ for the usual arrays but the \helpref{Add()}{wxarrayadd} method is
slower: it is $O(log(N))$ 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 not be used to store anything of
-sizeof() larger than max(sizeof(long), sizeof(void *)) - an assertion failure
-will be raised from the constructor otherwise.
+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
\begin{verbatim}
#include <wx/dynarray.h>
-// we must forward declare the array because it's used inside the class
+// we must forward declare the array because it is used inside the class
// declaration
class MyDirectory;
class MyFile;
...
// now that we have MyDirectory declaration in scope we may finish the
-// definition of ArrayOfDirectories
+// 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);
just to write
\begin{verbatim}
-WX_DEFINE_ARRAY(MyDirectory *, ArrayOfDirectories);
-WX_DEFINE_SORTED_ARRAY(MyFile *, ArrayOfFiles);
+WX_DEFINE_ARRAY(int, ArrayOfDirectories);
+WX_DEFINE_SORTED_ARRAY(int, ArrayOfFiles);
\end{verbatim}
+i.e. there is only one {\tt DEFINE} macro and no need for separate
+{\tt DECLARE} one.
+
+
\wxheading{See also:}
\helpref{Container classes overview}{wxcontaineroverview}, \helpref{wxList}{wxlist}
-\wxheading{Required headers:}
+\wxheading{Include files}
<wx/dynarray.h> for wxArray and wxSortedArray and additionally <wx/arrimpl.cpp>
for wxObjArray.
\latexignore{\rtfignore{\wxheading{Function groups}}}
-\membersection{Macros for template array definition}
+\membersection{Macros for template array definition}\label{arraymacros}
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
WX\_DEFINE\_OBJARRAY macro.
\helpref{WX\_DEFINE\_ARRAY}{wxdefinearray}\\
+\helpref{WX\_DEFINE\_EXPORTED\_ARRAY}{wxdefinearray}\\
+\helpref{WX\_DEFINE\_USER\_EXPORTED\_ARRAY}{wxdefinearray}\\
\helpref{WX\_DEFINE\_SORTED\_ARRAY}{wxdefinesortedarray}\\
-\helpref{WX\_DECLARE\_OBJARRAY}{wxdeclareobjarray}\\
-\helpref{WX\_DEFINE\_OBJARRAY}{wxdefineobjarray}
+\helpref{WX\_DEFINE\_SORTED\_EXPORTED\_ARRAY}{wxdefinesortedarray}\\
+\helpref{WX\_DEFINE\_SORTED\_USER\_EXPORTED\_ARRAY}{wxdefinesortedarray}\\
+\helpref{WX\_DECLARE\_EXPORTED\_OBJARRAY}{wxdeclareobjarray}\\
+\helpref{WX\_DECLARE\_USER\_EXPORTED\_OBJARRAY}{wxdeclareobjarray}\\
+\helpref{WX\_DEFINE\_OBJARRAY}{wxdefineobjarray}\\
+\helpref{WX\_DEFINE\_EXPORTED\_OBJARRAY}{wxdefineobjarray}\\
+\helpref{WX\_DEFINE\_USER\_EXPORTED\_OBJARRAY}{wxdefineobjarray}
+
+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
+{\tt \_PTR} versions of the macros above. For example, to define an array of
+pointers to {\tt double} you should use.
+
+Note that the above macros are generally only useful for
+wxObject types. There are seperate macros for declaring an array of a simple type,
+such as an int.
+
+The following simple types are supported:\\
+int\\
+long\\
+size\_t\\
+double
+
+To create an array of a simple type, simply append the type you want in CAPS to
+the array definition.
+
+For example, for an integer array, you'd use one of the following variants:
+
+\helpref{WX\_DEFINE\_ARRAY\_INT}{wxdefinearray}\\
+\helpref{WX\_DEFINE\_EXPORTED\_ARRAY\_INT}{wxdefinearray}\\
+\helpref{WX\_DEFINE\_USER\_EXPORTED\_ARRAY\_INT}{wxdefinearray}\\
+\helpref{WX\_DEFINE\_SORTED\_ARRAY\_INT}{wxdefinesortedarray}\\
+\helpref{WX\_DEFINE\_SORTED\_EXPORTED\_ARRAY\_INT}{wxdefinesortedarray}\\
+\helpref{WX\_DEFINE\_SORTED\_USER\_EXPORTED\_ARRAY\_INT}{wxdefinesortedarray}\\
+
+\begin{verbatim}
+WX_DEFINE_ARRAY_PTR(double *, MyArrayOfDoublePointers);
+\end{verbatim}
-\membersection{Constructors and destructors}
+\membersection{Constructors and destructors}\label{arrayconstructorsdestructors}
Array classes are 100\% C++ objects and as such they have the appropriate copy
constructors and assignment operators. Copying wxArray just copies the elements
ARRAY\_MAXSIZE\_INCREMENT constant. Of course, this may lead to some memory
being wasted (ARRAY\_MAXSIZE\_INCREMENT in the worst case, i.e. 4Kb in the
current implementation), so the \helpref{Shrink()}{wxarrayshrink} function is
-provided to unallocate the extra memory. The \helpref{Alloc()}{wxarrayalloc}
+provided to deallocate the extra memory. The \helpref{Alloc()}{wxarrayalloc}
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.
\helpref{Alloc}{wxarrayalloc}\\
\helpref{Shrink}{wxarrayshrink}
-\membersection{Number of elements and simple item access}
+\membersection{Number of elements and simple item access}\label{arrayelementsaccess}
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
\helpref{Item}{wxarrayitem}\\
\helpref{Last}{wxarraylast}
-\membersection{Adding items}
+\membersection{Adding items}\label{arrayadding}
\helpref{Add}{wxarrayadd}\\
-\helpref{Insert}{wxarrayinsert}
+\helpref{Insert}{wxarrayinsert}\\
+\helpref{SetCount}{wxarraysetcount}\\
+\helpref{WX\_APPEND\_ARRAY}{wxappendarray}
-\membersection{Removing items}
+\membersection{Removing items}\label{arrayremoving}
\helpref{WX\_CLEAR\_ARRAY}{wxcleararray}\\
\helpref{Empty}{wxarrayempty}\\
\helpref{Clear}{wxarrayclear}\\
+\helpref{RemoveAt}{wxarrayremoveat}\\
\helpref{Remove}{wxarrayremove}
-\membersection{Searching and sorting}
+\membersection{Searching and sorting}\label{arraysearchingandsorting}
\helpref{Index}{wxarrayindex}\\
\helpref{Sort}{wxarraysort}
\func{}{WX\_DEFINE\_ARRAY}{\param{}{T}, \param{}{name}}
+\func{}{WX\_DEFINE\_EXPORTED\_ARRAY}{\param{}{T}, \param{}{name}}
+
+\func{}{WX\_DEFINE\_USER\_EXPORTED\_ARRAY}{\param{}{T}, \param{}{name}, \param{}{exportspec}}
+
This macro defines a new array class named {\it name} and containing the
-elements of type {\it T}. Example:
+elements of type {\it T}. The second form is used when compiling wxWidgets as
+a DLL under Windows and array needs to be visible outside the DLL. The third is
+needed for exporting an array from a user DLL.
+
+Example:
\begin{verbatim}
-WX_DEFINE_ARRAY(int, wxArrayInt);
+WX_DEFINE_ARRAY_INT(wxArrayInt);
class MyClass;
WX_DEFINE_ARRAY(MyClass *, wxArrayOfMyClass);
\end{verbatim}
-Note that wxWindows predefines the following standard array classes: wxArrayInt,
+Note that wxWidgets predefines the following standard array classes: wxArrayInt,
wxArrayLong and wxArrayPtrVoid.
\membersection{WX\_DEFINE\_SORTED\_ARRAY}\label{wxdefinesortedarray}
\func{}{WX\_DEFINE\_SORTED\_ARRAY}{\param{}{T}, \param{}{name}}
+\func{}{WX\_DEFINE\_SORTED\_EXPORTED\_ARRAY}{\param{}{T}, \param{}{name}}
+
+\func{}{WX\_DEFINE\_SORTED\_USER\_EXPORTED\_ARRAY}{\param{}{T}, \param{}{name}}
+
This macro defines a new sorted array class named {\it name} and containing
-the elements of type {\it T}. Example:
+the elements of type {\it T}. The second form is used when compiling wxWidgets as
+a DLL under Windows and array needs to be visible outside the DLL. The third is
+needed for exporting an array from a user DLL.
+
+Example:
\begin{verbatim}
-WX_DEFINE_SORTED_ARRAY(int, wxArrayInt);
+WX_DEFINE_SORTED_ARRAY_INT(wxSortedArrayInt);
class MyClass;
WX_DEFINE_SORTED_ARRAY(MyClass *, wxArrayOfMyClass);
\end{verbatim}
-You will have to initialize the objects of this class by passing a comparaison
+You will have to initialize the objects of this class by passing a comparison
function to the array object constructor like this:
+
\begin{verbatim}
int CompareInts(int n1, int n2)
{
return n1 - n2;
}
-wxArrayInt sorted(CompareInts);
+wxSortedArrayInt sorted(CompareInts);
int CompareMyClassObjects(MyClass *item1, MyClass *item2)
{
\func{}{WX\_DECLARE\_OBJARRAY}{\param{}{T}, \param{}{name}}
+\func{}{WX\_DECLARE\_EXPORTED\_OBJARRAY}{\param{}{T}, \param{}{name}}
+
+\func{}{WX\_DECLARE\_USER\_EXPORTED\_OBJARRAY}{\param{}{T}, \param{}{name}}
+
This macro declares a new object array class named {\it name} and containing
-the elements of type {\it T}. Example:
+the elements of type {\it T}. The second form is used when compiling wxWidgets as
+a DLL under Windows and array needs to be visible outside the DLL. The third is
+needed for exporting an array from a user DLL.
+
+Example:
\begin{verbatim}
class MyClass;
-WX_DEFINE_OBJARRAY(MyClass, wxArrayOfMyClass); // note: not "MyClass *"!
+WX_DECLARE_OBJARRAY(MyClass, wxArrayOfMyClass); // note: not "MyClass *"!
\end{verbatim}
You must use \helpref{WX\_DEFINE\_OBJARRAY()}{wxdefineobjarray} macro to define
\func{}{WX\_DEFINE\_OBJARRAY}{\param{}{name}}
+\func{}{WX\_DEFINE\_EXPORTED\_OBJARRAY}{\param{}{name}}
+
+\func{}{WX\_DEFINE\_USER\_EXPORTED\_OBJARRAY}{\param{}{name}}
+
This macro defines the methods of the array class {\it name} not defined by the
\helpref{WX\_DECLARE\_OBJARRAY()}{wxdeclareobjarray} macro. You must include the
file <wx/arrimpl.cpp> before using this macro and you must have the full
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.
+not be called. The latter two forms are merely aliases of the first to satisfy
+some people's sense of symmetry when using the exported declarations.
Example of usage:
WX_DEFINE_OBJARRAY(wxArrayOfMyClass);
\end{verbatim}
+\membersection{WX\_APPEND\_ARRAY}\label{wxappendarray}
+
+\func{void}{WX\_APPEND\_ARRAY}{\param{wxArray\& }{array}, \param{wxArray\& }{other}}
+
+This macro may be used to append all elements of the {\it other} array to the
+{\it array}. The two arrays must be of the same type.
+
\membersection{WX\_CLEAR\_ARRAY}\label{wxcleararray}
-\func{\void}{WX\_CLEAR\_ARRAY}{\param{wxArray\& }{array}}
+\func{void}{WX\_CLEAR\_ARRAY}{\param{wxArray\& }{array}}
This macro may be used to delete all elements of the array before emptying it.
It can not be used with wxObjArrays - but they will delete their elements anyhow
\membersection{Default constructors}\label{wxarrayctordef}
-\func{}{wxArray}{}
+\func{}{wxArray}{\void}
-\func{}{wxObjArray}{}
+\func{}{wxObjArray}{\void}
Default constructor initializes an empty array object.
\func{}{wxSortedArray}{\param{int (*)(T first, T second)}{compareFunction}}
There is no default constructor for wxSortedArray classes - you must initialize it
-with a function to use for item comparaison. It is a function which is passed
+with a function to use for item comparison. It is a function which is passed
two arguments of type {\it T} where {\it 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.
\membersection{wxArray::Add}\label{wxarrayadd}
-\func{\void}{Add}{\param{T }{item}}
+\func{void}{Add}{\param{T }{item}, \param{size\_t}{ copies = $1$}}
-\func{\void}{Add}{\param{T *}{item}}
+\func{void}{Add}{\param{T *}{item}}
-\func{\void}{Add}{\param{T \&}{item}}
+\func{void}{Add}{\param{T \&}{item}, \param{size\_t}{ copies = $1$}}
-Appends a new element to the array (where {\it T} is the type of the array
-elements.)
+Appends the given number of {\it copies} of the {\it item} to the array
+consisting of the elements of type {\it T}.
The first version is used with wxArray and wxSortedArray. The second and the
-third are used with wxObjArray. There is an {\bf important difference} between
+third are used with wxObjArray. There is an important difference between
them: if you give a pointer to the array, it will take ownership of it, i.e.
will delete it when the item is deleted from the array. If you give a reference
to the array, however, the array will make a copy of the item and will not take
ownership of the original item. Once again, it only makes sense for wxObjArrays
-because the other array types never take ownership of their elements.
+because the other array types never take ownership of their elements. Also note
+that you cannot append more than one pointer as reusing it would lead to
+deleting it twice (or more) and hence to a crash.
+
+You may also use \helpref{WX\_APPEND\_ARRAY}{wxappendarray} macro to append all
+elements of one array to another one but it is more efficient to use
+{\it copies} parameter and modify the elements in place later if you plan to
+append a lot of items.
\membersection{wxArray::Alloc}\label{wxarrayalloc}
-\func{\void}{Alloc}{\param{size\_t }{count}}
+\func{void}{Alloc}{\param{size\_t }{count}}
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
\membersection{wxArray::Clear}\label{wxarrayclear}
-\func{\void}{Clear}{\void}
+\func{void}{Clear}{\void}
This function does the same as \helpref{Empty()}{wxarrayempty} and additionally
frees the memory allocated to the array.
\func{T *}{Detach}{\param{size\_t }{index}}
Removes the element from the array, but, unlike,
-
\helpref{Remove()}{wxarrayremove} doesn't delete it. The function returns the
pointer to the removed element.
\membersection{wxArray::Empty}\label{wxarrayempty}
-\func{\void}{Empty}{\void}
+\func{void}{Empty}{\void}
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
+array of being empty - this function does not free the allocated memory, use
\helpref{Clear()}{wxarrayclear} for this.
\membersection{wxArray::GetCount}\label{wxarraygetcount}
\membersection{wxArray::Index}\label{wxarrayindex}
-\func{int}{Index}{\param{T\& }{item}, \param{bool }{searchFromEnd = FALSE}}
+\func{int}{Index}{\param{T\& }{item}, \param{bool }{searchFromEnd = false}}
\func{int}{Index}{\param{T\& }{item}}
for wxSortedArray only.
Searches the element in the array, starting from either beginning or the end
-depending on the value of {\it searchFromEnd} parameter. wxNOT\_FOUND is
+depending on the value of {\it searchFromEnd} parameter. {\tt wxNOT\_FOUND} is
returned if the element is not found, otherwise the index of the element is
returned.
in the sorted array is used for wxSortedArray (this is why searchFromEnd
parameter doesn't make sense for it).
+{\bf NB:} even for wxObjArray classes, the operator==() of the elements in the
+array is {\bf 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.
+
\membersection{wxArray::Insert}\label{wxarrayinsert}
-\func{\void}{Insert}{\param{T }{item}, \param{size\_t }{n}}
+\func{void}{Insert}{\param{T }{item}, \param{size\_t }{n}, \param{size\_t }{copies = $1$}}
-\func{\void}{Insert}{\param{T *}{item}, \param{size\_t }{n}}
+\func{void}{Insert}{\param{T *}{item}, \param{size\_t }{n}}
-\func{\void}{Insert}{\param{T \&}{item}, \param{size\_t }{n}}
+\func{void}{Insert}{\param{T \&}{item}, \param{size\_t }{n}, \param{size\_t }{copies = $1$}}
-Insert a new item into the array before the item {\it n} - thus, {\it
-Insert(something, 0u}} will insert an item in such way that it will become the
-first array element.
+Insert the given number of {\it copies} of the {\it item} into the array before
+the existing item {\it n} - thus, {\it Insert(something, 0u)} will insert an
+item in such way that it will become the first array element.
Please see \helpref{Add()}{wxarrayadd} for explanation of the differences
between the overloaded versions of this function.
\membersection{wxArray::IsEmpty}\label{wxarrayisempty}
-\constfunc{bool}{IsEmpty}{}
+\constfunc{bool}{IsEmpty}{\void}
-Returns TRUE if the array is empty, FALSE otherwise.
+Returns true if the array is empty, false otherwise.
\membersection{wxArray::Item}\label{wxarrayitem}
\membersection{wxArray::Remove}\label{wxarrayremove}
-\func{\void}{Remove}{\param{size\_t }{index}}
-
\func{\void}{Remove}{\param{T }{item}}
-Removes the element from the array either by index or by value. When an element
-is removed from wxObjArray it is deleted by the array - use
+Removes an element from the array by value: the first item of the
+array equal to {\it 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
\helpref{Detach()}{wxobjarraydetach} 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 the it manually if required:
+should delete it manually if required:
\begin{verbatim}
T *item = array[n];
See also \helpref{WX\_CLEAR\_ARRAY}{wxcleararray} macro which deletes all
elements of a wxArray (supposed to contain pointers).
+\membersection{wxArray::RemoveAt}\label{wxarrayremoveat}
+
+\func{\void}{RemoveAt}{\param{size\_t }{index}, \param{size\_t }{count = $1$}}
+
+Removes {\it count} elements starting at {\it index} from the array. When an
+element is removed from wxObjArray it is deleted by the array - use
+\helpref{Detach()}{wxobjarraydetach} 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:
+
+\begin{verbatim}
+T *item = array[n];
+delete item;
+array.RemoveAt(n)
+\end{verbatim}
+
+See also \helpref{WX\_CLEAR\_ARRAY}{wxcleararray} macro which deletes all
+elements of a wxArray (supposed to contain pointers).
+
+\membersection{wxArray::SetCount}\label{wxarraysetcount}
+
+\func{void}{SetCount}{\param{size\_t }{count}, \param{T }{defval = T($0$)}}
+
+This function ensures that the number of array elements is at least
+{\it count}. If the array has already {\it count} or more items, nothing is
+done. Otherwise, {\tt count - GetCount()} elements are added and initialized to
+the value {\it defval}.
+
+\wxheading{See also}
+
+\helpref{GetCount}{wxarraygetcount}
+
\membersection{wxArray::Shrink}\label{wxarrayshrink}
-\func{\void}{Shrink}{\void}
+\func{void}{Shrink}{\void}
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.
\membersection{wxArray::Sort}\label{wxarraysort}
-\func{\void}{Sort}{\param{CMPFUNC<T> }{compareFunction}}
+\func{void}{Sort}{\param{CMPFUNC<T> }{compareFunction}}
The notation CMPFUNC<T> should be read as if we had the following declaration:
template int CMPFUNC(T *first, T *second);
\end{verbatim}
-where {\it T} is the type of the array elements. I.e. it is a function returning
+where {\it T} is the type of the array elements. I.e. it is a function returning
{\it int} which is passed two arguments of type {\it T *}.
Sorts the array using the specified compare function: this function should
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