wxWidgets/docs/latex/wx/mbconv.tex

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Name:        mbconv.tex
%% Purpose:     wxMBConv documentation
%% Author:      Ove Kaaven, Vadim Zeitlin
%% Created:     2000-03-25
%% RCS-ID:      $Id$
%% Copyright:   (c) 2000 Ove Kaaven
%%              (c) 2003-2006 Vadim Zeitlin
%% License:     wxWindows license
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


\section{\class{wxMBConv}}\label{wxmbconv}

This class is the base class of a hierarchy of classes capable of converting
text strings between multibyte (SBCS or DBCS) encodings and Unicode.

In the documentation for this and related classes please notice that 
\emph{length} of the string refers to the number of characters in the string
not counting the terminating \NUL, if any. While the \emph{size} of the string
is the total number of bytes in the string, including any trailing \NUL.
Thus, length of wide character string \texttt{L"foo"} is $3$ while its size can
be either $8$ or $16$ depending on whether \texttt{wchar\_t} is $2$ bytes (as
under Windows) or $4$ (Unix).

\wxheading{Global variables}

There are several predefined instances of this class:
\begin{twocollist}
\twocolitem{\textbf{wxConvLibc}}{Uses the standard ANSI C \texttt{mbstowcs()} and
\texttt{wcstombs()} functions to perform the conversions; thus depends on the
current locale.}
\twocolitem{\textbf{wxConvFile}}{The appropriate conversion for the file names,
depends on the system.}
\end{twocollist}

\wxheading{Derived from}

No base class

\wxheading{Include files}

<wx/strconv.h>

\wxheading{See also}

\helpref{wxCSConv}{wxcsconv}, 
\helpref{wxEncodingConverter}{wxencodingconverter}, 
\helpref{wxMBConv classes overview}{mbconvclasses}

\latexignore{\rtfignore{\wxheading{Members}}}


\membersection{wxMBConv::wxMBConv}\label{wxmbconvwxmbconv}

\func{}{wxMBConv}{\void}

Constructor.

\membersection{wxMBConv::MB2WC}\label{wxmbconvmb2wc}

\constfunc{virtual size\_t}{MB2WC}{\param{wchar\_t *}{out}, \param{const char *}{in}, \param{size\_t }{outLen}}

Converts from a string \arg{in} in multibyte encoding to Unicode putting up to 
\arg{outLen} characters into the buffer \arg{out}.

If \arg{out} is \NULL, only the length of the string which would result from
the conversion is calculated and returned. Note that this is the length and not
size, i.e. the returned value does \emph{not} include the trailing \NUL. But
when the function is called with a non-\NULL \arg{out} buffer, the \arg{outLen} 
parameter should be one more to allow to properly \NUL-terminate the string.

\wxheading{Parameters}

\docparam{out}{The output buffer, may be \NULL if the caller is only
interested in the length of the resulting string}

\docparam{in}{The \NUL-terminated input string, cannot be \NULL}

\docparam{outLen}{The length of the output buffer but \emph{including} 
\NUL, ignored if \arg{out} is \NULL}

\wxheading{Return value}

The length of the converted string \emph{excluding} the trailing \NUL.


\membersection{wxMBConv::WC2MB}\label{wxmbconvwc2mb}

\constfunc{virtual size\_t}{WC2MB}{\param{char* }{buf}, \param{const wchar\_t* }{psz}, \param{size\_t }{n}}

Converts from Unicode to multibyte encoding. The semantics of this function
(including the return value meaning) is the same as for 
\helpref{MB2WC}{wxmbconvmb2wc}.

Notice that when the function is called with a non-\NULL buffer, the 
{\it n} parameter should be the size of the buffer and so it \emph{should} take
into account the trailing \NUL, which might take two or four bytes for some
encodings (UTF-16 and UTF-32) and not one.


\membersection{wxMBConv::cMB2WC}\label{wxmbconvcmb2wc}

\constfunc{const wxWCharBuffer}{cMB2WC}{\param{const char *}{in}}

\constfunc{const wxWCharBuffer}{cMB2WC}{\param{const char *}{in}, \param{size\_t }{inLen}, \param{size\_t }{*outLen}}

Converts from multibyte encoding to Unicode by calling 
\helpref{MB2WC}{wxmbconvmb2wc}, allocating a temporary wxWCharBuffer to hold
the result.

The first overload takes a \NUL-terminated input string. The second one takes a
string of exactly the specified length and the string may include or not the
trailing \NUL character(s). If the string is not \NUL-terminated, a temporary 
\NUL-terminated copy of it suitable for passing to \helpref{MB2WC}{wxmbconvmb2wc} 
is made, so it is more efficient to ensure that the string is does have the
appropriate number of \NUL bytes (which is usually $1$ but may be $2$ or $4$
for UTF-16 or UTF-32, see \helpref{GetMBNulLen}{wxmbconvgetmbnullen}),
especially for long strings.

If \arg{outLen} is not-\NULL, it receives the length of the converted
string.


\membersection{wxMBConv::cWC2MB}\label{wxmbconvcwc2mb}

\constfunc{const wxCharBuffer}{cWC2MB}{\param{const wchar\_t* }{in}}

\constfunc{const wxCharBuffer}{cWC2MB}{\param{const wchar\_t* }{in}, \param{size\_t }{inLen}, \param{size\_t }{*outLen}}

Converts from Unicode to multibyte encoding by calling WC2MB,
allocating a temporary wxCharBuffer to hold the result.

The second overload of this function allows to convert a string of the given
length \arg{inLen}, whether it is \NUL-terminated or not (for wide character
strings, unlike for the multibyte ones, a single \NUL is always enough).
But notice that just as with \helpref{cMB2WC}{wxmbconvmb2wc}, it is more
efficient to pass an already terminated string to this function as otherwise a
copy is made internally.

If \arg{outLen} is not-\NULL, it receives the length of the converted
string.


\membersection{wxMBConv::cMB2WX}\label{wxmbconvcmb2wx}

\constfunc{const char*}{cMB2WX}{\param{const char* }{psz}}

\constfunc{const wxWCharBuffer}{cMB2WX}{\param{const char* }{psz}}

Converts from multibyte encoding to the current wxChar type
(which depends on whether wxUSE\_UNICODE is set to 1). If wxChar is char,
it returns the parameter unaltered. If wxChar is wchar\_t, it returns the
result in a wxWCharBuffer. The macro wxMB2WXbuf is defined as the correct
return type (without const).


\membersection{wxMBConv::cWX2MB}\label{wxmbconvcwx2mb}

\constfunc{const char*}{cWX2MB}{\param{const wxChar* }{psz}}

\constfunc{const wxCharBuffer}{cWX2MB}{\param{const wxChar* }{psz}}

Converts from the current wxChar type to multibyte encoding. If wxChar is char,
it returns the parameter unaltered. If wxChar is wchar\_t, it returns the
result in a wxCharBuffer. The macro wxWX2MBbuf is defined as the correct
return type (without const).


\membersection{wxMBConv::cWC2WX}\label{wxmbconvcwc2wx}

\constfunc{const wchar\_t*}{cWC2WX}{\param{const wchar\_t* }{psz}}

\constfunc{const wxCharBuffer}{cWC2WX}{\param{const wchar\_t* }{psz}}

Converts from Unicode to the current wxChar type. If wxChar is wchar\_t,
it returns the parameter unaltered. If wxChar is char, it returns the
result in a wxCharBuffer. The macro wxWC2WXbuf is defined as the correct
return type (without const).


\membersection{wxMBConv::cWX2WC}\label{wxmbconvcwx2wc}

\constfunc{const wchar\_t*}{cWX2WC}{\param{const wxChar* }{psz}}

\constfunc{const wxWCharBuffer}{cWX2WC}{\param{const wxChar* }{psz}}

Converts from the current wxChar type to Unicode. If wxChar is wchar\_t,
it returns the parameter unaltered. If wxChar is char, it returns the
result in a wxWCharBuffer. The macro wxWX2WCbuf is defined as the correct
return type (without const).


\membersection{wxMBConv::GetMBNulLen}\label{wxmbconvgetmbnullen}

\constfunc{size\_t}{GetMBNulLen}{\void}

This function returns $1$ for most of the multibyte encodings in which the
string is terminated by a single \NUL, $2$ for UTF-16 and $4$ for UTF-32 for
which the string is terminated with $2$ and $4$ \NUL characters respectively.
The other cases are not currently supported and $-1$ is returned for them.