+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% Name: array.tex
+%% Purpose: wxArray
+%% Author: wxWidgets Team
+%% Modified by:
+%% Created:
+%% RCS-ID: $Id$
+%% Copyright: (c) wxWidgets Team
+%% License: wxWindows license
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
\section{\class{wxArray}}\label{wxarray}
This section describes the so called {\it dynamic arrays}. This is a C
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. This class has one serious
+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 wxWindows).
+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 is
+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
It is not as elegant as writing
-\begin{verbatim}
+\begin{verbatim}
typedef std::vector<MyDirectory> ArrayOfDirectories;
\end{verbatim}
Things are much simpler for wxArray and wxSortedArray however: it is enough
just to write
-\begin{verbatim}
-WX_DEFINE_ARRAY(MyDirectory *, ArrayOfDirectories);
-WX_DEFINE_SORTED_ARRAY(MyFile *, ArrayOfFiles);
+\begin{verbatim}
+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}
\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
\helpref{WX\_DEFINE\_EXPORTED\_OBJARRAY}{wxdefineobjarray}\\
\helpref{WX\_DEFINE\_USER\_EXPORTED\_OBJARRAY}{wxdefineobjarray}
-\membersection{Constructors and destructors}
+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:
+
+\begin{verbatim}
+WX_DEFINE_ARRAY_PTR(double *, MyArrayOfDoublePointers);
+\end{verbatim}
+
+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:\\
+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}\\
+
+\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 deallocate 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{SetCount}{wxarraysetcount}\\
\helpref{WX\_APPEND\_ARRAY}{wxappendarray}
-\membersection{Removing items}
+\membersection{Removing items}\label{arrayremoving}
\helpref{WX\_CLEAR\_ARRAY}{wxcleararray}\\
\helpref{Empty}{wxarrayempty}\\
\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\_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}. The second form is used when compiling wxWindows as
+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(int, MyArrayInt);
class MyClass;
-WX_DEFINE_ARRAY(MyClass *, wxArrayOfMyClass);
+WX_DEFINE_ARRAY(MyClass *, ArrayOfMyClass);
\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\_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}. The second form is used when compiling wxWindows as
+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, wxSortedArrayInt);
+WX_DEFINE_SORTED_ARRAY_INT(int, MySortedArrayInt);
class MyClass;
-WX_DEFINE_SORTED_ARRAY(MyClass *, wxArrayOfMyClass);
+WX_DEFINE_SORTED_ARRAY(MyClass *, ArrayOfMyClass);
\end{verbatim}
You will have to initialize the objects of this class by passing a comparison
\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}. The second form is used when compiling wxWindows as
+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.
\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\_USER\_EXPORTED\_OBJARRAY}{\param{}{name}}
-This macro defines the methods of the array class {\it name} not defined by the
+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
-declaration of the class of array elements in scope! If you forget to do the
+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
\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
+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{}{\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
+done by wxArray and wxSortedArray versions - you may use
\helpref{WX\_CLEAR\_ARRAY}{wxcleararray} macro for this.
\membersection{wxArray::Add}\label{wxarrayadd}
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
+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.
\func{T *}{Detach}{\param{size\_t }{index}}
-Removes the element from the array, but, unlike,
+Removes the element from the array, but, unlike,
\helpref{Remove()}{wxarrayremove} doesn't delete it. The function returns the
pointer to the removed element.
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}}
+\constfunc{int}{Index}{\param{T\& }{item}, \param{bool }{searchFromEnd = false}}
-\func{int}{Index}{\param{T\& }{item}}
+\constfunc{int}{Index}{\param{T\& }{item}}
The first version of the function is for wxArray and wxObjArray, the second is
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.
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
+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:
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}
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
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.
-
projects / wxWidgets.git / blobdiff