wxWidgets/interface/convauto.h
2008-04-12 23:27:36 +00:00

98 lines
4.5 KiB
Objective-C

/////////////////////////////////////////////////////////////////////////////
// Name: convauto.h
// Purpose: interface of wxConvAuto
// Author: wxWidgets team
// RCS-ID: $Id$
// Licence: wxWindows license
/////////////////////////////////////////////////////////////////////////////
/**
@class wxConvAuto
@wxheader{convauto.h}
This class implements a Unicode to/from multibyte converter capable of
automatically recognizing the encoding of the multibyte text on input. The
logic used is very simple: the class uses the BOM (byte order mark) if it's
present and tries to interpret the input as UTF-8 otherwise. If this fails,
the input is interpreted as being in the default multibyte encoding which
can be specified in the constructor of a wxConvAuto instance and, in turn,
defaults to the value of GetFallbackEncoding() if not explicitly given.
For the conversion from Unicode to multibyte, the same encoding as was
previously used for multibyte to Unicode conversion is reused. If there had
been no previous multibyte to Unicode conversion, UTF-8 is used by default.
Notice that once the multibyte encoding is automatically detected, it
doesn't change any more, i.e. it is entirely determined by the first use of
wxConvAuto object in the multibyte-to-Unicode direction. However creating a
copy of wxConvAuto object, either via the usual copy constructor or
assignment operator, or using wxMBConv::Clone(), resets the automatically
detected encoding so that the new copy will try to detect the encoding of
the input on first use.
This class is used by default in wxWidgets classes and functions reading
text from files such as wxFile, wxFFile, wxTextFile, wxFileConfig and
various stream classes so the encoding set with its SetFallbackEncoding()
method will affect how these classes treat input files. In particular, use
this method to change the fall-back multibyte encoding used to interpret
the contents of the files whose contents isn't valid UTF-8 or to disallow
it completely.
@library{wxbase}
@category{data}
@see @ref overview_mbconv
*/
class wxConvAuto : public wxMBConv
{
public:
/**
Constructs a new wxConvAuto instance. The object will try to detect the
input of the multibyte text given to its wxMBConv::ToWChar() method
automatically but if the automatic detection of Unicode encodings
fails, the fall-back encoding @a enc will be used to interpret it as
multibyte text.
The default value of @a enc, @c wxFONTENCODING_DEFAULT, means that the
global default value (which can be set using SetFallbackEncoding())
should be used. As with that method, passing @c wxFONTENCODING_MAX
inhibits using this encoding completely so the input multibyte text
will always be interpreted as UTF-8 in the absence of BOM and the
conversion will fail if the input doesn't form valid UTF-8 sequence.
Another special value is @c wxFONTENCODING_SYSTEM which means to use
the encoding currently used on the user system, i.e. the encoding
returned by wxLocale::GetSystemEncoding(). Any other encoding will be
used as is, e.g. passing @c wxFONTENCODING_ISO8859_1 ensures that
non-UTF-8 input will be treated as latin1.
*/
wxConvAuto(wxFontEncoding enc = wxFONTENCODING_DEFAULT);
/**
Disable the use of the fall back encoding: if the input doesn't have a
BOM and is not valid UTF-8, the conversion will fail.
*/
static void DisableFallbackEncoding();
/**
Returns the encoding used by default by wxConvAuto if no other encoding
is explicitly specified in constructor. By default, returns
@c wxFONTENCODING_ISO8859_1 but can be changed using
SetFallbackEncoding().
*/
static wxFontEncoding GetFallbackEncoding();
/**
Changes the encoding used by default by wxConvAuto if no other encoding
is explicitly specified in constructor. The default value, which can be
retrieved using GetFallbackEncoding(), is @c wxFONTENCODING_ISO8859_1.
Special values of @c wxFONTENCODING_SYSTEM or @c wxFONTENCODING_MAX can
be used for the @a enc parameter to use the encoding of the current
user locale as fall back or not use any encoding for fall back at all,
respectively (just as with the similar constructor parameter). However,
@c wxFONTENCODING_DEFAULT can't be used here.
*/
static void SetFallbackEncoding(wxFontEncoding enc);
};