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
-compile your application in debug mode to use it (see \helpref{debugging
-overview}{debuggingoverview} for details). So, unlike the arrays in some other
+compile your application in debug mode to use it (see \helpref{debugging overview}{debuggingoverview} 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
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 you may find some
-useful hints about optimizing wxArray memory usage. As for executable size, all
+but the price is preallocating the memory in advance. In the \helpref{memory management}{wxarraymemorymanagement} 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 {\it any space at all}.
wxWindows has three different kinds of array. All of them derive from
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
-\helpref{Index()}{wxarrayindex} function execution time is $O(log(N))$ instead of
+ \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
...
// 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 linkin 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
\begin{verbatim}
typedef std::vector<MyDirectory> ArrayOfDirectories;
\end{verbatim}
+
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}
never use wxBaseArray anyhow it shouldn't be a problem) and that you should not
derive your own classes from the array classes.
-\helpref{wxArray default constructor}{wxarrayctordef}
-\helpref{wxArray copy constructors and assignment operators}{wxarrayctorcopy}
+\helpref{wxArray default constructor}{wxarrayctordef}\\
+\helpref{wxArray copy constructors and assignment operators}{wxarrayctorcopy}\\
\helpref{\destruct{wxArray}}{wxarraydtor}
\membersection{Memory management}\label{wxarraymemorymanagement}
amount, but no more than some maximal number which is defined by
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
+current implementation), so the \helpref{Shrink()}{wxarrayshrink} function is
provided to unallocate 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
\helpref{Last}{wxarraylast}
\membersection{Adding items}
+
\helpref{Add}{wxarrayadd}\\
\helpref{Insert}{wxarrayinsert}
\membersection{Removing items}
+
\helpref{WX\_CLEAR\_ARRAY}{wxcleararray}\\
\helpref{Empty}{wxarrayempty}\\
\helpref{Clear}{wxarrayclear}\\
\helpref{Remove}{wxarrayremove}
\membersection{Searching and sorting}
+
\helpref{Index}{wxarrayindex}\\
\helpref{Sort}{wxarraysort}
}}
\membersection{WX\_DEFINE\_ARRAY}\label{wxdefinearray}
-\func{}{WX\_DEFINE\_ARRAY}{\param{}{T}, \param{name}}
+
+\func{}{WX\_DEFINE\_ARRAY}{\param{}{T}, \param{}{name}}
This macro defines a new array class named {\it name} and containing the
elements of type {\it T}. Example:
+
\begin{verbatim}
WX_DEFINE_ARRAY(int, wxArrayInt);
wxArrayLong and wxArrayPtrVoid.
\membersection{WX\_DEFINE\_SORTED\_ARRAY}\label{wxdefinesortedarray}
-\func{}{WX\_DEFINE\_SORTED\_ARRAY}{\param{}{T}, \param{name}}
+
+\func{}{WX\_DEFINE\_SORTED\_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:
+
\begin{verbatim}
-WX_DEFINE_SORTED_ARRAY(int, wxArrayInt);
+WX_DEFINE_SORTED_ARRAY(int, wxSortedArrayInt);
class MyClass;
WX_DEFINE_SORTED_ARRAY(MyClass *, wxArrayOfMyClass);
return n1 - n2;
}
-wxArrayInt sorted(CompareInts);
+wxSortedArrayInt sorted(CompareInts);
int CompareMyClassObjects(MyClass *item1, MyClass *item2)
{
\end{verbatim}
\membersection{WX\_DECLARE\_OBJARRAY}\label{wxdeclareobjarray}
-\func{}{WX\_DECLARE\_OBJARRAY}{\param{}{T}, \param{name}}
+
+\func{}{WX\_DECLARE\_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:
+
\begin{verbatim}
class MyClass;
WX_DEFINE_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.
\membersection{WX\_DEFINE\_OBJARRAY}\label{wxdefineobjarray}
-\func{}{WX\_DEFINE\_OBJARRAY}{\param{name}}
+
+\func{}{WX\_DEFINE\_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
not be called.
Example of usage:
+
\begin{verbatim}
// first declare the class!
class MyClass
\end{verbatim}
\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}
-\func{}{wxArray}{}
-\func{}{wxObjArray}{}
+\membersection{Default constructors}\label{wxarrayctordef}
+
+\func{}{wxArray}{\void}
+
+\func{}{wxObjArray}{\void}
Default constructor initializes an empty array object.
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{}{wxSortedArray}{\param{const wxSortedArray\& }{array}}
+
\func{}{wxObjArray}{\param{const wxObjArray\& }{array}}
-\func{wxArray\&}{operator=}{\param{const wxArray\& }{array}}
-\func{wxSortedArray\&}{operator=}{\param{const wxSortedArray\& }{array}}
-\func{wxObjArray\&}{operator=}{\param{const wxObjArray\& }{array}}
+\func{wxArray\&}{operator$=$}{\param{const wxArray\& }{array}}
+
+\func{wxSortedArray\&}{operator$=$}{\param{const wxSortedArray\& }{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
the array element are copied too) for wxObjArray.
\membersection{wxArray::\destruct{wxArray}}\label{wxarraydtor}
-\func{}{\destruct{wxArray}}{}
-\func{}{\destruct{wxSortedArray}}{}
-\func{}{\destruct{wxObjArray}}{}
+
+\func{}{\destruct{wxArray}}{\void}
+
+\func{}{\destruct{wxSortedArray}}{\void}
+
+\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
\helpref{WX\_CLEAR\_ARRAY}{wxcleararray} macro for this.
\membersection{wxArray::Add}\label{wxarrayadd}
-\func{\void}{Add}{\param{T }{item}}
-\func{\void}{Add}{\param{T *}{item}}
-\func{\void}{Add}{\param{T \&}{item}}
+
+\func{void}{Add}{\param{T }{item}}
+
+\func{void}{Add}{\param{T *}{item}}
+
+\func{void}{Add}{\param{T \&}{item}}
Appends a new element to the array (where {\it T} is the type of the array
elements.)
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
because the other array types never take ownership of their elements.
\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
has enough memory for the given number of items, nothing happens.
\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.
\membersection{wxArray::Count}\label{wxarraycount}
+
\constfunc{size\_t}{Count}{\void}
Same as \helpref{GetCount()}{wxarraygetcount}. This function is deprecated -
it exists only for compatibility.
\membersection{wxObjArray::Detach}\label{wxobjarraydetach}
+
\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}
+
\constfunc{size\_t}{GetCount}{\void}
Return the number of items in the array.
\membersection{wxArray::Index}\label{wxarrayindex}
+
\func{int}{Index}{\param{T\& }{item}, \param{bool }{searchFromEnd = FALSE}}
+
\func{int}{Index}{\param{T\& }{item}}
The first version of the function is for wxArray and wxObjArray, the second is
parameter doesn't make sense for it).
\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}}
-\func{\void}{Insert}{\param{T \&}{item}, \param{size\_t }{n}}
-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
+\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}}
+
+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.
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.
\membersection{wxArray::Item}\label{wxarrayitem}
+
\constfunc{T\&}{Item}{\param{size\_t }{index}}
Returns the item at the given position in the array. If {\it index} is out of
the array classes.
\membersection{wxArray::Last}\label{wxarraylast}
+
\constfunc{T\&}{Last}{\void}
Returns the last element in the array, i.e. is the same as Item(GetCount() - 1).
the array classes.
\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
\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:
+
\begin{verbatim}
T *item = array[n];
delete item;
elements of a wxArray (supposed to contain pointers).
\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.
allocated again.
\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:
+
\begin{verbatim}
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.
+
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