wxString docs are nearly complete (but don't compile :-( ), a brief threads

overview


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@1781 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
This commit is contained in:
Vadim Zeitlin 1999-02-24 23:53:40 +00:00
parent ec9f78844b
commit 99f09bc1b9
5 changed files with 783 additions and 54 deletions

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@ -4,3 +4,4 @@ wxCursorRefData
wxCursor::SetHCURSOR
wxCursor::GetHCURSOR
wxCursor::FreeResource
wxStringData

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@ -1,6 +1,265 @@
\section{wxString overview}\label{wxstringoverview}
Classes: \helpref{wxString}{wxstring}
Classes: \helpref{wxString}{wxstring}, \helpref{wxArrayString}{wxarray}, \helpref{wxStringTokenizer}{wxstringtokenizer}
TODO.
\subsection{Introduction}
wxString is a class which represents a character string of arbitrary (limited by
{\it MAX\_INT} which is usually 2147483647 on 32 bit machines) length and containing
arbitrary characters (i.e. ASCII NUL character is allowed, although care should be
taken when passing strings containing it to other functions).
wxString only works with ASCII (8 bit characters) strings as of this release,
however support for UNICODE (16 but characters) is planned for the next one.
This class has all standard operations you can expect to find in a string class:
dynamic memory management (string extends to accomodate new characters),
construction from other strings, C strings and characters, assignment operators,
access to separate characters, string concatenation and comparison, substring
extraction, case conversion, trimming and padding (with spaces), searching and
replacing and both C-like \helpref{Printf()}{wxstringprintf} and stream-like
insertion functions as well as much else - see \helpref{wxString}{wxstring}
for the list of all functions.
\subsection{Comparison of wxString to other string classes}
The advantages of using a special string class instead of working directly with
C strings are so obvious (the most imoprtant being, of course, the need to always
remember to allocate/free memory for C strings unless the programmer prefers
working with fixed size buffers which almost certainly leads to the dreaded
buffer overflows) that there is a huge number of such classes available and now,
finally, C++ even has one (std::string) in standard. Why use wxString then?
There are several advantages:
\begin{enumerate}\itemsep=0pt
\item {\bf Efficiency} {This class was made to be as efficient as possible: both
in terms of size (each wxString objects takes exactly the same place as {\it
char *} pointer, \helpref{reference counting}{wxstringrefcount}) and speed.
It also provides performance \helpref{statistics gathering code}{wxstringtuning}
which may be enabled to fine tune the memory allocation strategy for your
particular application - and the gain might be quite big.}
\item {\bf Compatibility} {This class tries to combine almost full compatibility
with the old wxWindows 1.xx wxString class, some reminiscence to MFC CString
class and 90\% of functionality of std::string class.}
\item {\bf Rich set of functions} {Some of the functions present in wxString are
very useful but don't exist in most of other string classes: for example,
\helpref{AfterFirst}{wxstringafterfirst},
\helpref{BeforLast}{wxstringbeforlast}, \helpref{operator<<}{wxstringoperator}
or \helpref{Printf}{wxstringprintf}. Of course, all the standard string
operations are supported as well.}
\item {\bf UNICODE} {In this release, wxString only supports construction from
an UNICODE string, but in the next one it will be capable of also storing its
internal data in either ASCII or UNICODE format.}
\item {\bf Used by wxWindows} {And, of course, this class is used everywhere
inside wxWindows so there is no performance loss which would result from
conversions of objects of any other string class (including std::string) to
wxString internally by wxWindows.}
\end{enumerate}
However, there are several problems as well. The most important one is probably
that there are often several functions to do exactly the same thing: for
example, to get the length of the string either one of
\helpref{length()}{wxstringlength}, \helpref{Len()}{wxstringlen} or
\helpref{Length()}{wxstringLength} may be used. The first function, as almost
all the other functions in lowercase, is std::string compatible. The second one
is "native" wxString version and the last one is wxWindows 1.xx way. So the
question is: which one is better to use? And the answer is that:
{\bf The usage of std::string compatible functions is strongly advised!} It will
both make your code more familiar to other C++ programmers (who are supposed to
have knowledge of std::string but not of wxString), let you reuse the same code
in both wxWindows and other programs (by just typedefing wxString as std::string
when used outside wxWindows) and by staying compatible with future versions of
wxWindows which will probably start using std::string sooner or later too.
In the situations when there is no correspondinw std::string function, please
try to use the new wxString methods and not the old wxWindows 1.xx variants
which are deprecated and risk to disappear in future versions.
\subsection{Some advices about using wxString}\label{wxstringadvices}
Probably main trap with using this class is the implicit conversion operator to
{\it const char *}. It is advised that you use \helpref{c\_str()}{wxstringcstr}
instead of it to clearly indicate when the conversion is done. Specifically, the
danger of this implicit conversion may be seen in the following code fragment:
\begin{verbatim}
// this function converts the input string to uppercase, output it to the screen
// and returns the result
const char *SayHELLO(const wxString& input)
{
wxString output = input.Upper();
printf("Hello, %s!\n", output);
return output;
}
\end{verbatim}
There are two nasty bugs in these three lines. First of them is in the call to
{\it printf()} function. Although the implicit conversion to C strings is applied
automatically by the compiler in case of
\begin{verbatim}
puts(output);
\end{verbatim}
because the argument of {\it puts()} is known to be of the type {\it const char
*}, this is {\bf not} done for {\it printf()} which is a function with variable
number of arguments (and whose arguments are of unknown types). So this call may
do anything at all (including displaying the correct string on screen), although
the most likely result is a program crash. The solution is to use
\helpref{c\_str()}{wxstringcstr}: just replace this line with
\begin{verbatim}
printf("Hello, %s!\n", output.c_str());
\end{verbatim}
The second bug is that returning {\it output} doesn't work. The implicit cast is
used again, so the code compiles, but as it returns a pointer to a buffer
belonging to a local variable which is deleted as soon as the function exits,
its contents is totally arbitrary. The solution to this problem is also easy:
just make the function return wxString instead of C string.
This leads us to the following general advice: all functions taking string
arguments should take {\it const wxString\&} (this makes assignment to the
strings inside the function faster because of
\helpref{reference counting}{wxstringrefcount}) and all functions returning
strings should return {\it wxString} - this makes it safe to return local
variables.
\subsection{Other string related functions and classes}
As any program operates with character strings, the standard C library provides quite a
few of functions to work with them. Unfortunately, some of them have rather non
intuitive behaviour (like strncpy() which doesn't always terminate the resulting
string with a NUL) and are in general not very safe (passing NULL to them will
probably lead to program crash). Moreover, some of very useful functions are not
standard at all. This is why in addition to all wxString functions, there are
also a few of global string functions which try to correct these problems:
\helpref{IsEmpty()}{isempty} verifies whether the string is empty (returning
TRUE for NULL pointers), \helpref{Strlen()}{strlen} also handles NULLs correctly
and returns 0 for them and \helpref{Stricmp()}{stricmp} is just a
platform-independent version of case-insensitive string comparison function
known either as stricmp() or strcasecmp() on different platforms.
There is another class which might be useful when working with wxString:
\helpref{wxStringTokenizer}{wxstringtokenizer}. It is helpful when a string must
be broken into tokens and replaces advatageously the standard C library {\it
strtok()} function.
And the very last string related class is \helpref{wxArrayString}{wxarray}: it
is just a version of "template" dynamic array class which is specialized to work
with strings. Please note that this class is specially optimized (it uses its
knowledge of internal structure of wxString) for storing strigns and so it is
vastly better from performance point of view than wxObjectArray of wxString.
\subsection{Reference counting and why you shouldn't care about it}\label{wxstringrefcount}
wxString objects use a technique known as {\it copy on write} (COW). This means
that when a string is assigned to another, no copying really takes place: only
the reference count on the shared string data is increased and both strings
share the same data.
But as soon as one of the two (or more) strings is modified, the data has to be
copied because the changes to one of the strings shouldn't be seen in the
otheres. As data copying only happens when the string is written to, this is
known as COW.
What is important to understand is that all this happens absolutely
transparently to the class users and that whether a string is shared or not is
not seen from the outside of the class - in any case, the result of any
operation on it is the same.
Probably the unique case when you might want to think about reference
counting is when a string character is taken from a string which is not a
constant (or a constant reference). In this case, due to C++ rules, the
"read-only" {\it operator[]} (which is the same as
\helpref{GetChar()}{wxstringgetchar}) cannot be chosen and the "read/write"
{\it operator[]} (the same as
\helpref{GetWritableChar()}{wxstringgetwritablechar}) is used instead. As the
call to this operator may modify the string, its data is unshared (COW is done)
and so if the string was really shared there is some performance loss (both in
terms of speed and memory consumption). In the rare cases when this may be
important, you might prefer using \helpref{GetChar()}{wxstringgetchar} instead
of array subscript operator for this reasons. Please note that
\helpref{at()}{wxstringat} method has the same problem as subscript operator in
this situation and so using it is not really better. Also note that if all
string arguments to your functions are passed as {\it const wxString\&} (see the
section \helpref{Some advices}{wxstringadvices}) this situation will almost
never arise because for constant references the correct operator is called automatically.
\subsection{Tuning wxString for your application}\label{wxstringtuning}
\normalbox{{\bf Note:} this section is strictly about performance issues and is
absolutely not necessary to read for using wxString class. Please skip it unless
you feel familiar with profilers and relative tools. If you do read it, please
also read the preceding section about
\helpref{reference counting}{wxstringrefcounting}.}
For the performance reasons wxString doesn't allocate exactly the amount of
memory needed for each string. Instead, it adds a small amount of space to each
allocated block which allows it to not reallocate memory (this is a relatively
expensive operation) too often as when, for example, a string is constructed by
subsequently adding one character at a time to it, as for example in:
\begin{verbatim}
// delete all vowels from the string
wxString DeleteAllVowels(const wxString& original)
{
wxString result;
size_t len = original.length();
for ( size_t n = 0; n < len; n++ )
{
if ( strchr("aeuio", tolower(original[n])) == NULL )
result += original[n];
}
return result;
}
\end{verbatim}
This is a quite common situation and not allocating extra memory at all would
lead to very bad performance in this case because there would be as many memory
(re)allocations as there are consonants in the original string. Allocating too
much extra memory would help to improve the speed in this situation, but due to
a great number of wxString objects typically used in a program would also
increase the memory consumption too much.
The very best solution in precisely this case would be to use
\helpref{Alloc()}{wxstringalloc} function to preallocate, for example, len bytes
from the beginning - this will lead to exactly one memory allocation being
performed (because the result is at most as long as the original string).
However, using Alloc() is tedious and so wxString tries to do its best. The
default algorithm assumes that memory allocation is done in granularity of at
least 16 bytes (which is the case on almost all of wide-spread platforms) and so
nothing is lost if the amount of memory to allocate is rounded up to the next
multiple of 16. Like this, no memory is lost and 15 iterations from 16 in the
example above won't allocate memory but use the already allocated pool.
The default approach is quite conservative. Allocating more memory may bring
important performance benefits for programs using (relatively) few very long
strings. The amount of memory allocated is configured by the setting of {\it
EXTRA\_ALLOC} in the file string.cpp during compilation (be sure to understand
why its default value is what it is before modifying it!). You may try setting
it to greater amount (say twice nLen) or to 0 (to see performance degradation
which will follow) and analyse the impact of it on your program. If you do it,
you will probably find it helpful to also define WXSTRING\_STATISTICS symbol
which tells the wxString class to collect performance statistics and to show
them on stderr on program termination. This will show you the average length of
strings your program manipulates, their average initial length and also the
percent of times when memory wasn't reallocated when string concatenation was
done but the alread preallocated memory was used (this value should be about
98\% for the default allocation policy, if it is less than 90\% you should
really consider fine tuning wxString for your application).
It goes without saying that a profiler should be used to measure the precise
difference the change to EXTRA\_ALLOC makes to your program.

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@ -4,5 +4,39 @@ Classes: \helpref{wxThread}{wxthread}, \helpref{wxMutex}{wxmutex},
\helpref{wxCriticalSection}{wxcriticalsection},
\helpref{wxCondition}{wxcondition}
TODO
wxWindows provides a complete set of classes encapsulating objects necessary in
multithreaded (MT) programs: the \helpref{thread}{wxthread} class itself and different
synchronization objects: \helpref{mutexes}{wxmutex} and
\helpref{critical sections}{wxcriticalsection} with
\helpref{conditions}{wxcondition}.
These classes will hopefully make writing MT programs easier and they also
provide some extra error checking (compared to the native (be it Win32 or Posix)
thread API), however it is still an untrivial undertaking especially for large
projects. Before starting an MT application (or starting to add MT features to
an existing one) it is worth asking oneself if there is no easier and safer way
to implement the same functionality. Of course, in some situations threads
really make sense (classical example is a server application which launches a
new thread for each new client), but in others it might be a very poor choice
(example: launching a separate thread when doing a long computation to show a
progress dialog). Other implementation choices are available: for the progress
dialog example it is far better to do the calculations in the
\helpref{idle handler}{wxidleevent} or call \helpref{wxYield()}{wxyield}
periodically to update the screen.
If you do decide to use threads in your application, it is strongly recommended
that no more than one thread calls GUI functions. The thread sample shows that
it {\it is} possible for many different threads to call GUI functions at once
(all the threads created in the sample access GUI), but it is a very poor design
choice for anything except an example. The design which uses one GUI thread and
several worker threads which communicate with the main one using events is much
more robust and will undoubtedly save you countless problems (example: under
Win32 a thread can only access GDI objects such as pens, brushes, \&c created by
itself and not by the other threads).
Final note: in the current release of wxWindows, there are no specific
facilities for communicating between the threads. However, the usual
\helpref{ProcessEvent()}{wxevthandlerprocessevent} function may be used for
thread communication too - but you should provide your own synchronisation
mechanism if you use it (e.g. just use a critical section before sending a
message) because there is no built-in synchronisation.

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@ -1,5 +1,13 @@
\section{\class{wxString}}\label{wxstring}
wxString is a class representing a character string. Please see wxString
\helpref{overview}{wxstringoverview} for more information about it. As explained
there, wxStrign implements about 90\% of methods of std::string class (iterators
are not supported and so all methods which use them are not supported neither),
but they are not documented here - please see any source of STL documentation.
The behaviour of all these functions is identical to the behaviour described
there.
\wxheading{Derived from}
None
@ -12,7 +20,332 @@ None
\overview{Overview}{wxstringoverview}
\latexignore{\rtfignore{\wxheading{Members}}}
\latexignore{\rtfignore{\wxheading{Function groups}}}
\membersection{Constructors and assignment operators}
A strign may be constructed either from a C string, (some number of copies of)
a single character or a wide (UNICODE) string. For all constructors (except the
default which creates an empty string) there is also a corresponding assignment
operator.
\helpref{wxString}{wxstringconstruct}\\
\helpref{operator $=$}{wxstringoperatorassign}\\
\helpref{\destruct{wxString}}{wxstringdestruct}
\membersection{String length}
These functions return the string length and check whether the string is empty
or empty it.
\helpref{Len}{wxstringlen}\\
\helpref{IsEmpty}{wxstringisempty}\\
\helpref{operator!}{wxstringoperatornot}\\
\helpref{Empty}{wxstringempty}\\
\helpref{Clear}{wxstringclear}
\membersection{Character access}
Many functions in this section take a character index in the string. As with C
strings and/or arrays, the indices start from $0$, so the first character of a
string is string[$0$]. Attempt to access a character beyond the end of the
string (which may be even $0$ if the string is empty) will provocate an assert
failure in \helpref{debug build}{debuggingoverview}, but no checks are done in
release builds.
This section also contains both implicit and explicit conversions to C style
strings. Although implicit conversion is quite convenient, it is advised to use
explicit \helpref{c\_str()}{wxstringcstr} method for the sake of clarity. Also
see \helpref{overiview}{wxstringadvices} for the cases where it is necessary to
use it.
\helpref{GetChar}{wxstringgetchar}\\
\helpref{GetWritableChar}{wxstringgetwritablechar}\\
\helpref{SetChar}{wxstringsetchar}\\
\helpref{Last}{wxstringlast}\\
\helpref{operator []}{wxstringoperatorbracket}\\
\helpref{c\_str}{wxstringcstr}\\
\helpref{operator const char*}{wxstringoperatorconstcharpt}
\membersection{Concatenation}
Anything may be concatenated (appended to) with a string. However, you can't
append something to a C string (including literal constants), so to do this it
should be converted to a wxString first.
\helpref{operator \cinsert}{wxstringoperatorout}\\
\helpref{operator $+=$}{wxstringplusequal}\\
\helpref{operator $+$}{wxstringoperatorplus}\\
\helpref{Append}{wxstringappend}\\
\helpref{Prepend}{wxstringprepend}
\membersection{Comparison}
The default comparison function \helpref{Cmp}{wxstringcmp} is case-sensitive and
so is the default version of \helpref{IsSameAs}{wxstringissameas}. For case
insensitive comparisons you should use \helpref{CmpNoCase}{wxstringcmpnocase} or
give a second parameter to IsSameAs. This last function is may be more
convenient if only equality of the strings matters because it returns a boolean
true value if the strings are the same and not 0 (which is usually FALSE in C)
as Cmp does.
\helpref{Matches}{wxstringmatches} is a poor man's regular expression matcher:
it only understands '*' and '?' metacharacters in the sense of DOS command line
interpreter.
\helpref{Cmp}{wxstringcmp}\\
\helpref{CmpNoCase}{wxstringcmpnocase}\\
\helpref{IsSameAs}{wxstringissameas}\\
\helpref{Matches}{wxstringmatches}
\membersection{Substring extraction}
These functions allow to extract substring from this string. All of them don't
modify the original string and return a new string containing the extracted
substring.
\helpref{Mid}{wxstringmid}\\
\helpref{operator()}{wxstringoperatorparenth}\\
\helpref{Left}{wxstringleft}\\
\helpref{Right}{wxstringright}\\
\helpref{BeforeFirst}{wxstringbeforefirst}\\
\helpref{BeforeLast}{wxstringbeforelast}\\
\helpref{AfterFirst}{wxstringafterfirst}\\
\helpref{AfterLast}{wxstringafterlast}
\membersection{Case conversion}
The MakeXXX() variants modify the string in place, while the other functions
return a new string which containts the original text converted to the upper or
lower case and leave the original string unchanged.
\helpref{MakeUpper}{wxstringmakeupper}\\
\helpref{Upper}{wxstringupper}\\
\helpref{MakeLower}{wxstringmakelower}\\
\helpref{Lower}{wxstringlower}
\membersection{Searching and replacing}
These functions replace the standard {\it strchr()} and {\it strstr()}
functions.
\helpref{Find}{wxstringfind}\\
\helpref{Replace}{wxstringreplace}
\membersection{Writing values into the string}
Both formatted versions (\helpref{Printf}{wxstringprintf}) and stream-like
insertion operators exist (for basic types only).
\helpref{Printf}{wxstringprintf}\\
\helpref{PrintfV}{wxstringprintfv}\\
\helpref{operator \cinsert}{wxstringoperatorout)
\membersection{Memory management}
These are "advanced" functions and they will be needed quite rarily.
\helpref{Alloc}{wxstringalloc} and \helpref{Shrink}{wxstringshrink} are only
interesting for optimization purposes.
\helpref{GetWriteBuf}{wxstringgetwritebuf} may be very useful when working with
some external API which requires the caller to provide a writable buffer, but
extreme care should be taken when using it: before performing any other
operation on the string \helpref{UngetWriteBuf}{wxstringungetwritebuf} {\bf
must} be called!
\helpref{Alloc}{wxstringalloc}\\
\helpref{Shrink}{wxstringshrink}\\
\helpref{GetWriteBuf}{wxstringgetwritebuf}\\
\helpref{UngetWriteBuf}{wxstringungetwritebuf}
\membersection{Miscellaneous}
Other string functions.
\helpref{Trim}{wxstringtrim}\\
\helpref{Pad}{wxstringpad}\\
\helpref{Truncate}{wxstringtruncate}
\membersection{wxWindows 1.xx compatiblity functions}
These functiosn are deprecated, please consider using new wxWindows 2.0
functions instead of them (or, even better, std::string compatible variants).
\helpref{SubString}{wxstringsubstring}\\
\helpref{sprintf}{wxstringsprintf}\\
\helpref{CompareTo}{wxstringcompareto}\\
\helpref{Length}{wxstringlength}\\
\helpref{Freq}{wxstringfreq}\\
\helpref{LowerCase}{wxstringlowercase}\\
\helpref{UpperCase}{wxstringuppercase}\\
\helpref{Strip}{wxstringstrip}\\
\helpref{Index}{wxstringindex}\\
\helpref{Remove}{wxstringremove}\\
\helpref{First}{wxstringfirst}\\
\helpref{Last}{wxstringlast}\\
\helpref{Contains}{wxstringcontains}\\
\helpref{IsNull}{wxstringisnull}\\
\helpref{IsAscii}{wxstringisascii}\\
\helpref{IsNumber}{wxstringisnumber}\\
\helpref{IsWord}{wxstringisword}
\membersection{std::string compatibility functions}
The supported functions are only listed here, please see any STL reference for
their documentation.
\begin{verbatim}
// take nLen chars starting at nPos
wxString(const wxString& str, size_t nPos, size_t nLen);
// take all characters from pStart to pEnd (poor man's iterators)
wxString(const void *pStart, const void *pEnd);
// lib.string.capacity
// return the length of the string
size_t size() const;
// return the length of the string
size_t length() const;
// return the maximum size of the string
size_t max_size() const;
// resize the string, filling the space with c if c != 0
void resize(size_t nSize, char ch = '\0');
// delete the contents of the string
void clear();
// returns true if the string is empty
bool empty() const;
// lib.string.access
// return the character at position n
char at(size_t n) const;
// returns the writable character at position n
char& at(size_t n);
// lib.string.modifiers
// append a string
wxString& append(const wxString& str);
// append elements str[pos], ..., str[pos+n]
wxString& append(const wxString& str, size_t pos, size_t n);
// append first n (or all if n == npos) characters of sz
wxString& append(const char *sz, size_t n = npos);
// append n copies of ch
wxString& append(size_t n, char ch);
// same as `this_string = str'
wxString& assign(const wxString& str);
// same as ` = str[pos..pos + n]
wxString& assign(const wxString& str, size_t pos, size_t n);
// same as `= first n (or all if n == npos) characters of sz'
wxString& assign(const char *sz, size_t n = npos);
// same as `= n copies of ch'
wxString& assign(size_t n, char ch);
// insert another string
wxString& insert(size_t nPos, const wxString& str);
// insert n chars of str starting at nStart (in str)
wxString& insert(size_t nPos, const wxString& str, size_t nStart, size_t n);
// insert first n (or all if n == npos) characters of sz
wxString& insert(size_t nPos, const char *sz, size_t n = npos);
// insert n copies of ch
wxString& insert(size_t nPos, size_t n, char ch);
// delete characters from nStart to nStart + nLen
wxString& erase(size_t nStart = 0, size_t nLen = npos);
// replaces the substring of length nLen starting at nStart
wxString& replace(size_t nStart, size_t nLen, const char* sz);
// replaces the substring with nCount copies of ch
wxString& replace(size_t nStart, size_t nLen, size_t nCount, char ch);
// replaces a substring with another substring
wxString& replace(size_t nStart, size_t nLen,
const wxString& str, size_t nStart2, size_t nLen2);
// replaces the substring with first nCount chars of sz
wxString& replace(size_t nStart, size_t nLen,
const char* sz, size_t nCount);
// swap two strings
void swap(wxString& str);
// All find() functions take the nStart argument which specifies the
// position to start the search on, the default value is 0. All functions
// return npos if there were no match.
// find a substring
size_t find(const wxString& str, size_t nStart = 0) const;
// find first n characters of sz
size_t find(const char* sz, size_t nStart = 0, size_t n = npos) const;
// find the first occurence of character ch after nStart
size_t find(char ch, size_t nStart = 0) const;
// rfind() family is exactly like find() but works right to left
// as find, but from the end
size_t rfind(const wxString& str, size_t nStart = npos) const;
// as find, but from the end
size_t rfind(const char* sz, size_t nStart = npos,
size_t n = npos) const;
// as find, but from the end
size_t rfind(char ch, size_t nStart = npos) const;
// find first/last occurence of any character in the set
//
size_t find_first_of(const wxString& str, size_t nStart = 0) const;
//
size_t find_first_of(const char* sz, size_t nStart = 0) const;
// same as find(char, size_t)
size_t find_first_of(char c, size_t nStart = 0) const;
//
size_t find_last_of (const wxString& str, size_t nStart = npos) const;
//
size_t find_last_of (const char* s, size_t nStart = npos) const;
// same as rfind(char, size_t)
size_t find_last_of (char c, size_t nStart = npos) const;
// find first/last occurence of any character not in the set
//
size_t find_first_not_of(const wxString& str, size_t nStart = 0) const;
//
size_t find_first_not_of(const char* s, size_t nStart = 0) const;
//
size_t find_first_not_of(char ch, size_t nStart = 0) const;
//
size_t find_last_not_of(const wxString& str, size_t nStart=npos) const;
//
size_t find_last_not_of(const char* s, size_t nStart = npos) const;
//
size_t find_last_not_of(char ch, size_t nStart = npos) const;
// All compare functions return a negative, zero or positive value
// if the [sub]string is less, equal or greater than the compare() argument.
// just like strcmp()
int compare(const wxString& str) const;
// comparison with a substring
int compare(size_t nStart, size_t nLen, const wxString& str) const;
// comparison of 2 substrings
int compare(size_t nStart, size_t nLen,
const wxString& str, size_t nStart2, size_t nLen2) const;
// just like strcmp()
int compare(const char* sz) const;
// substring comparison with first nCount characters of sz
int compare(size_t nStart, size_t nLen,
const char* sz, size_t nCount = npos) const;
// substring extraction
wxString substr(size_t nStart = 0, size_t nLen = npos) const;
\end{verbatim}
%%%%% MEMBERS HERE %%%%%
\helponly{\insertatlevel{2}{
\wxheading{Members}
}}
\membersection{wxString::wxString}\label{wxstringconstruct}
@ -28,15 +361,15 @@ Copy constructor.
Constructs a string of {\it n} copies of character {\it ch}.
\func{}{wxString}{\param{const char*}{ psz}, \param{size\_t}{ nLength = STRING\_MAXLEN}}
\func{}{wxString}{\param{const char*}{ psz}, \param{size\_t}{ nLength = wxSTRING\_MAXLEN}}
Takes first {\it nLength} characters from the C string {\it psz}.
The default value of STRING\_MAXLEN means take all the string.
The default value of wxSTRING\_MAXLEN means take all the string.
\func{}{wxString}{\param{const unsigned char*}{ psz}, \param{size\_t}{ nLength = STRING\_MAXLEN}}
\func{}{wxString}{\param{const unsigned char*}{ psz}, \param{size\_t}{ nLength = wxSTRING\_MAXLEN}}
For compilers using unsigned char: takes first {\it nLength} characters from the C string {\it psz}.
The default value of STRING\_MAXLEN means take all the string.
The default value of wxSTRING\_MAXLEN means take all the string.
\func{}{wxString}{\param{const wchar\_t*}{ psz}}
@ -48,13 +381,44 @@ Constructs a string from the wide (UNICODE) string.
String destructor. Note that this is not virtual, so wxString must not be inherited from.
\membersection{wxString::Alloc}\label{wxstringAlloc}
\membersection{wxString::Alloc}\label{wxstringalloc}
\func{void}{Alloc}{\param{uint}{ newsize}}
\func{void}{Alloc}{\param{size\_t}{ nLen}}
Preallocate some space for wxString. Only works if the data of this string is not shared.
Preallocate enough space for wxString to store {\it nLen} characters. This function
may be used to increase speed when the string is constructed by repeated
concatenation as in
\membersection{wxString::Append}\label{wxstringAppend}
\begin{verbatim}
// delete all vowels from the string
wxString DeleteAllVowels(const wxString& original)
{
wxString result;
size_t len = original.length();
result.Alloc(len);
for ( size_t n = 0; n < len; n++ )
{
if ( strchr("aeuio", tolower(original[n])) == NULL )
result += original[n];
}
return result;
}
\end{verbatim}
because it will avoid the need of reallocating string memory many times (in case
of long strings). Note that it does not set the maximal length of a string - it
will still expand if more than {\it nLen} characters are stored in it. Also, it
does not truncate the existing string (use
\helpref{Truncate()}{wxstringtruncate} for this) even if its current length is
greater than {\it nLen}
\membersection{wxString::Append}\label{wxstringappend}
\func{wxString\&}{Append}{\param{const char*}{ psz}}
@ -65,19 +429,33 @@ Concatenates {\it psz} to this string, returning a reference to it.
Concatenates character {\it ch} to this string, {\it count} times, returning a reference
to it.
\membersection{wxString::After}\label{wxstringAfter}
\membersection{wxString::AfterFirst}\label{wxstringafterfirst}
\constfunc{wxString}{After}{\param{char}{ ch}}
\constfunc{wxString}{AfterFirst}{\param{char}{ ch}}
Gets all the characters after the first occurence of {\it ch}.
Returns the empty string if {\it ch} is not found.
\membersection{wxString::Before}\label{wxstringBefore}
\membersection{wxString::AfterLast}\label{wxstringafterlast}
\constfunc{wxString}{Before}{\param{char}{ ch}}
\constfunc{wxString}{AfterLast}{\param{char}{ ch}}
Gets all the characters after the last occurence of {\it ch}.
Returns the whole string if {\it ch} is not found.
\membersection{wxString::BeforeFirst}\label{wxstringbeforefirst}
\constfunc{wxString}{BeforeFirst}{\param{char}{ ch}}
Gets all characters before the first occurence of {\it ch}.
Returns the whole string if {\it ch} is not found.
\membersection{wxString::BeforeLast}\label{wxstringbeforelast}
\constfunc{wxString}{BeforeLast}{\param{char}{ ch}}
Gets all characters before the last occurence of {\it ch}.
Returns empty string if {\it ch} is not found.
Returns the empty string if {\it ch} is not found.
\membersection{wxString::Cmp}\label{wxstringcmp}
@ -85,9 +463,11 @@ Returns empty string if {\it ch} is not found.
Case-sensitive comparison.
Returns 0 if equal, +1 if greater or -1 if less.
Returns a positive value if the string is greater than the argument, zero if
it si equal to it or negative value if it is less than argument (same semantics
as the standard {\it strcmp()} function).
See also CmpNoCase, IsSameAs.
See also \helpref{CmpNoCase}{wxstringcmpnocase}, \helpref{IsSameAs}{wxstringissameas}.
\membersection{wxString::CmpNoCase}\label{wxstringcmpnocase}
@ -95,11 +475,13 @@ See also CmpNoCase, IsSameAs.
Case-insensitive comparison.
Returns 0 if equal, +1 if greater or -1 if less.
Returns a positive value if the string is greater than the argument, zero if
it si equal to it or negative value if it is less than argument (same semantics
as the standard {\it strcmp()} function).
See also Cmp, IsSameAs.
See also \helpref{Cmp}{wxstringcmp}, \helpref{IsSameAs}{wxstringissameas}.
\membersection{wxString::CompareTo}\label{wxstringCompareTo}
\membersection{wxString::CompareTo}\label{wxstringcompareto}
\begin{verbatim}
#define NO_POS ((int)(-1)) // undefined position
@ -110,9 +492,9 @@ enum caseCompare {exact, ignoreCase};
Case-sensitive comparison. Returns 0 if equal, 1 if greater or -1 if less.
\membersection{wxString::Contains}\label{wxstringContains}
\membersection{wxString::Contains}\label{wxstringcontains}
\func{bool}{Contains}{\param{const wxString\&}{ str}}
\constfunc{bool}{Contains}{\param{const wxString\&}{ str}}
Returns 1 if target appears anyhere in wxString; else 0.
@ -144,13 +526,19 @@ Searches for the given string. Returns the starting index, or -1 if not found.
Returns the first occurrence of the item.
\membersection{wxString::Freq}\label{wxstringfreq}
\constfunc{int}{Frec}{\param{char }{ch}}
Returns the number of occurences of {it ch} in the string.
\membersection{wxString::GetChar}\label{wxstringgetchar}
\constfunc{char}{GetChar}{\param{size\_t}{ n}}
Returns the character at position {\it n} (read-only).
\membersection{wxString::GetData}\label{wxstringGetData}
\membersection{wxString::GetData}\label{wxstringgetdata}
\constfunc{const char*}{GetData}{\void}
@ -164,14 +552,14 @@ Returns a reference to the character at position {\it n}.
\membersection{wxString::GetWriteBuf}\label{wxstringgetwritebuf}
\func{char*}{GetWriteBuf}{\param{uint}{ len}}
\func{char*}{GetWriteBuf}{\param{size\_t}{ len}}
Returns a writable buffer of at least {\it len} bytes.
Call \helpref{wxString::UngetWriteBuf}{wxstringungetwritebuf} as soon as possible
to put the string back into a reasonable state.
\membersection{wxString::Index}\label{wxstringIndex}
\membersection{wxString::Index}\label{wxstringindex}
\constfunc{size\_t}{Index}{\param{char}{ ch}, \param{int}{ startpos = 0}}
@ -194,11 +582,11 @@ Returns the index of the first item matched, or NOT\_FOUND.
% TODO
%\membersection{wxString::insert}\label{wxstringinsert}
% Wrong!
%\func{void}{insert}{\param{const wxString\&}{ str}, \param{uint}{ index}}
%\func{void}{insert}{\param{const wxString\&}{ str}, \param{size\_t}{ index}}
%
%Add new element at the given position.
%
\membersection{wxString::IsAscii}\label{wxstringIsAscii}
\membersection{wxString::IsAscii}\label{wxstringisascii}
\constfunc{bool}{IsAscii}{\void}
@ -210,13 +598,13 @@ Returns TRUE if the string is ASCII.
Returns TRUE if the string is NULL.
\membersection{wxString::IsNull}\label{wxstringIsNull}
\membersection{wxString::IsNull}\label{wxstringisnull}
\constfunc{bool}{IsNull}{\void}
Returns TRUE if the string is NULL (same as IsEmpty).
\membersection{wxString::IsNumber}\label{wxstringIsNumber}
\membersection{wxString::IsNumber}\label{wxstringisnumber}
\constfunc{bool}{IsNumber}{\void}
@ -232,15 +620,15 @@ caseSensitive is TRUE by default (case matters).
Returns TRUE if strings are equal, FALSE otherwise.
See also Cmp, CmpNoCase.
See also \helpref{Cmp}{wxstringcmp}, \helpref{CmpNoCase}{wxstringcmpnocase}.
\membersection{wxString::IsWord}\label{wxstringIsWord}
\membersection{wxString::IsWord}\label{wxstringisword}
\constfunc{bool}{IsWord}{\void}
Returns TRUE if the string is a word. TODO: what's the definition of a word?
\membersection{wxString::Last}\label{wxstringLast}
\membersection{wxString::Last}\label{wxstringlast}
\constfunc{char}{Last}{\void}
@ -273,7 +661,13 @@ Returns the length of the string.
Returns the length of the string (same as Len).
\membersection{wxString::LowerCase}\label{wxstringLowerCase}
\membersection{wxString::Lower}\label{wxstringlower}
\constfunc{wxString}{Lower}{\void}
Returns this string converted to the lower case.
\membersection{wxString::LowerCase}\label{wxstringlowercase}
\func{void}{LowerCase}{\void}
@ -291,7 +685,7 @@ Converts all characters to lower case.
Converts all characters to upper case.
\membersection{wxString::Matches}\label{wxstringMatches}
\membersection{wxString::Matches}\label{wxstringmatches}
\constfunc{bool}{Matches}{\param{const char*}{ szMask}}
@ -299,7 +693,7 @@ Returns TRUE if the string contents matches a mask containing '*' and '?'.
\membersection{wxString::Mid}\label{wxstringmid}
\constfunc{wxString}{Mid}{\param{size\_t}{ first}, \param{size\_t}{ count = STRING\_MAXLEN}}
\constfunc{wxString}{Mid}{\param{size\_t}{ first}, \param{size\_t}{ count = wxSTRING\_MAXLEN}}
Returns a substring starting at {\it first}, with length {\it count}, or the rest of
the string if {\it count} is the default value.
@ -312,7 +706,7 @@ Adds {\it count} copies of {\it pad} to the beginning, or to the end of the stri
Removes spaces from the left or from the right (default).
\membersection{wxString::Prepend}\label{wxstringPrepend}
\membersection{wxString::Prepend}\label{wxstringprepend}
\func{wxString\&}{Prepend}{\param{const wxString\&}{ str}}
@ -322,8 +716,13 @@ Prepends {\it str} to this string, returning a reference to this string.
\func{int}{Printf}{\param{const char* }{pszFormat}, \param{}{...}}
Similar to sprintf. Returns the number of characters written, or an integer less than zero
on error.
Similar to the standard function {\it sprintf()}. Returns the number of
characters written, or an integer less than zero on error.
{\bf NB:} This function will use a safe version of {\it vsprintf()} (usually called
{\it vsnprintf()}) whenever available to always allocate the buffer of correct
size. Unfortunately, this function is not available on all platforms and the
dangerous {\it vsprintf()} will be used then which may lead to buffer overflows.
\membersection{wxString::PrintfV}\label{wxstringprintfv}
@ -332,7 +731,7 @@ on error.
Similar to vprintf. Returns the number of characters written, or an integer less than zero
on error.
\membersection{wxString::Remove}\label{wxstringRemove}
\membersection{wxString::Remove}\label{wxstringremove}
\func{wxString\&}{Remove}{\param{size\_t}{ pos}}
@ -348,9 +747,9 @@ Removes the last {\it len} characters from the string, starting at {\it pos}.
Removes the last character.
\membersection{wxString::Replace}\label{wxstringReplace}
\membersection{wxString::Replace}\label{wxstringreplace}
\func{uint}{Replace}{\param{const char*}{ szOld}, \param{const char*}{ szNew}, \param{bool}{ replaceAll}}
\func{size\_t}{Replace}{\param{const char*}{ szOld}, \param{const char*}{ szNew}, \param{bool}{ replaceAll = TRUE}}
Replace first (or all) occurences of substring with another one.
@ -379,7 +778,8 @@ Sets the character at position {\it n}.
\func{void}{Shrink}{\void}
Minimizes the string's memory. Only works if the data of this string is not shared.
Minimizes the string's memory. This can be useful after a call to
\helpref{Alloc()}{wxstringalloc} if too much memory were preallocated.
\membersection{wxString::sprintf}\label{wxstringsprintf}
@ -387,7 +787,7 @@ Minimizes the string's memory. Only works if the data of this string is not shar
The same as Printf.
\membersection{wxString::Strip}\label{wxstringStrip}
\membersection{wxString::Strip}\label{wxstringstrip}
\begin{verbatim}
enum stripType {leading = 0x1, trailing = 0x2, both = 0x3};
@ -398,6 +798,12 @@ enum stripType {leading = 0x1, trailing = 0x2, both = 0x3};
Strip characters at the front and/or end. The same as Trim except that it
doesn't change this string.
\membersection{wxString::SubString}\label{wxstringsubstring}
\constfunc{wxString}{SubString}{\param{size\_t}{ to}, \param{size\_t}{ from}}
Same as \helpref{Mid}{wxstringmid}.
\membersection{wxString::Trim}\label{wxstringtrim}
\func{wxString\&}{Trim}{\param{bool}{ fromRight = TRUE}}
@ -417,12 +823,29 @@ Truncate the string to the given length.
Puts the string back into a reasonable state, after
\rtfsp\helpref{wxString::GetWriteBuf}{wxstringgetwritebuf} was called.
\membersection{wxString::UpperCase}\label{wxstringUpperCase}
\membersection{wxString::Upper}\label{wxstringupper}
\constfunc{wxString}{Upper}{\void}
Returns this string converted to upper case.
\membersection{wxString::UpperCase}\label{wxstringuppercase}
\func{void}{UpperCase}{\void}
The same as MakeUpper.
\membersection{wxString::operator!}\label{wxstringoperatornot}
\constfunc{bool}{operator!}{\void}
Empty string is FALSE, so !string will only return TRUE if the string is empty.
This allows the tests for NULLness of a {\it const char *} pointer and emptyness
of the string to look the same in the code and makes it easier to port old code
to wxString.
See also \helpref{IsEmpty()}{wxstringisempty}.
\membersection{wxString::operator $=$}\label{wxstringoperatorassign}
\func{wxString\&}{operator $=$}{\param{const wxString\&}{ str}}
@ -435,11 +858,13 @@ The same as MakeUpper.
\func{wxString\&}{operator $=$}{\param{const wchar\_t*}{ pwz}}
Assignment.
Assignment: the effect of each operation is the same as for the corresponding
constructor (see \helpref{wxString constructors}{wxstringconstruct}).
\membersection{operator wxString::$+$}\label{wxstringoperatorplus}
Concatenation.
Concatenation: all these operators return a new strign equal to the sum of the
operands.
\func{wxString}{operator $+$}{\param{const wxString\&}{ x}, \param{const wxString\&}{ y}}
@ -449,7 +874,7 @@ Concatenation.
\func{wxString}{operator $+$}{\param{const char*}{ x}, \param{const wxString\&}{ y}}
\membersection{wxString::operator $+=$}\label{wxstringPlusEqual}
\membersection{wxString::operator $+=$}\label{wxstringplusequal}
\func{void}{operator $+=$}{\param{const wxString\&}{ str}}
@ -457,7 +882,7 @@ Concatenation.
\func{void}{operator $+=$}{\param{char}{ c}}
Concatenation.
Concatenation in place: the argument is appended to the string.
\membersection{wxString::operator []}\label{wxstringoperatorbracket}
@ -485,6 +910,16 @@ Same as Mid (substring extraction).
Same as $+=$.
\func{wxString\&}{operator \cinsert}{\param{int}{ i}}
\func{wxString\&}{operator \cinsert}{\param{float}{ f}}
\func{wxString\&}{operator \cinsert}{\param{double}{ d}}
These functions work as C++ stream insertion operators: they insert the given
value into the string. Precision or format cannot be set using them, you can use
\helpref{Printf}{wxstringprintf} for this.
\membersection{wxString::operator \cextract}\label{wxstringoperatorin}
\func{friend istream\&}{operator \cextract}{\param{istream\&}{ is}, \param{wxString\&}{ str}}
@ -497,7 +932,7 @@ Extraction from a stream.
Implicit conversion to a C string.
\membersection{Comparison operators}\label{wxstringComparison}
\membersection{Comparison operators}\label{wxstringcomparison}
\func{bool}{operator $==$}{\param{const wxString\&}{ x}, \param{const wxString\&}{ y}}