This section describes the so called {\it dynamic arrays}. This is a C
array-like data structure i.e. the member access time is constant (and not
-linear in number of container elements as for linked lists). However, these
+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
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 if, of course, constant (independent of number of elements)
+array item access is, of course, constant (independent of the number of elements)
making them much more efficient than linked lists (\helpref{wxList}{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 \helpref{memory management}{wxarraymemorymanagement} section
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 \&c. It should be noted that
-all of wxArray functions are inline, so it costs strictly nothing to define as
+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 wxWindows internally.
+because wxArrays are used by wxWindows 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 wxWindows).
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. As wxArray this array can not
-be used
+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
\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);
// that's all!
-
\end{verbatim}
It is not as elegant as writing
but is not that complicated and allows the code to be compiled with any, however
dumb, C++ compiler in the world.
-The things are much simpler for wxArray and wxSortedArray however: it is enough
+Things are much simpler for wxArray and wxSortedArray however: it is enough
just to write
\begin{verbatim}
\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.
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}
\membersection{Constructors and destructors}
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.
\membersection{Adding items}
\helpref{Add}{wxarrayadd}\\
-\helpref{Insert}{wxarrayinsert}
+\helpref{Insert}{wxarrayinsert}\\
+\helpref{SetCount}{wxarraysetcount}\\
+\helpref{WX\_APPEND\_ARRAY}{wxappendarray}
\membersection{Removing items}
\helpref{WX\_CLEAR\_ARRAY}{wxcleararray}\\
\helpref{Empty}{wxarrayempty}\\
\helpref{Clear}{wxarrayclear}\\
+\helpref{RemoveAt}{wxarrayremoveat}\\
\helpref{Remove}{wxarrayremove}
\membersection{Searching and sorting}
\membersection{WX\_DEFINE\_ARRAY}\label{wxdefinearray}
-\func{}{WX\_DEFINE\_ARRAY}{\param{}{T}, \param{name}}
+\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 wxWindows 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);
\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 wxWindows 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 wxWindows 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
the array class - otherwise you would get link errors.
\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
when you call Empty().
-\membersection{Default constructors}\label{wxarrayctor}
+\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 copy constructor and assignemnt operator}\label{wxarrayctorcopy}
+\membersection{wxArray copy constructor and assignment operator}\label{wxarrayctorcopy}
\func{}{wxArray}{\param{const wxArray\& }{array}}
\func{}{wxObjArray}{\param{const wxObjArray\& }{array}}
-\func{wxArray\&}{operator=}{\param{const wxArray\& }{array}}
+\func{wxArray\&}{operator$=$}{\param{const wxArray\& }{array}}
-\func{wxSortedArray\&}{operator=}{\param{const wxSortedArray\& }{array}}
+\func{wxSortedArray\&}{operator$=$}{\param{const wxSortedArray\& }{array}}
-\func{wxObjArray\&}{operator=}{\param{const wxObjArray\& }{array}}
+\func{wxObjArray\&}{operator$=$}{\param{const wxObjArray\& }{array}}
The copy constructors and assignment operators perform a shallow array copy
(i.e. they don't copy the objects pointed to even if the source array contains
\membersection{wxArray::\destruct{wxArray}}\label{wxarraydtor}
-\func{}{\destruct{wxArray}}{}
+\func{}{\destruct{wxArray}}{\void}
-\func{}{\destruct{wxSortedArray}}{}
+\func{}{\destruct{wxSortedArray}}{\void}
-\func{}{\destruct{wxObjArray}}{}
+\func{}{\destruct{wxObjArray}}{\void}
The wxObjArray destructor deletes all the items owned by the array. This is not
done by wxArray and wxSortedArray versions - you may use
\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}}
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 mroe 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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