/////////////////////////////////////////////////////////////////////////////
-// Name: mbconvclasses
+// Name: mbconvclasses.h
// Purpose: topic overview
// Author: wxWidgets team
// RCS-ID: $Id$
// Licence: wxWindows license
/////////////////////////////////////////////////////////////////////////////
-/*!
-
- @page mbconvclasses_overview wxMBConv classes overview
-
- Classes: #wxMBConv, wxMBConvLibc,
- #wxMBConvUTF7, #wxMBConvUTF8,
- #wxCSConv,
- #wxMBConvUTF16, #wxMBConvUTF32
- The wxMBConv classes in wxWidgets enable an Unicode-aware application to
- easily convert between Unicode and the variety of 8-bit encoding systems still
- in use.
- @ref needforconversion_overview
- @ref conversionandwxstring_overview
- @ref mbconvclasses_overview
- @ref mbconvobjects_overview
- #wxCSConv
- @ref convertingstrings_overview
- @ref convertingbuffers_overview
-
-
- @section needforconversion Background: The need for conversion
-
- As programs are becoming more and more globalized, and users exchange documents
- across country boundaries as never before, applications increasingly need to
- take into account all the different character sets in use around the world. It
- is no longer enough to just depend on the default byte-sized character set that
- computers have traditionally used.
- A few years ago, a solution was proposed: the Unicode standard. Able to contain
- the complete set of characters in use in one unified global coding system,
- it would resolve the character set problems once and for all.
- But it hasn't happened yet, and the migration towards Unicode has created new
- challenges, resulting in "compatibility encodings" such as UTF-8. A large
- number of systems out there still depends on the old 8-bit encodings, hampered
- by the huge amounts of legacy code still widely deployed. Even sending
- Unicode data from one Unicode-aware system to another may need encoding to an
- 8-bit multibyte encoding (UTF-7 or UTF-8 is typically used for this purpose), to
- pass unhindered through any traditional transport channels.
-
- @section conversionandwxstring Background: The wxString class
-
- If you have compiled wxWidgets in Unicode mode, the wxChar type will become
- identical to wchar_t rather than char, and a wxString stores wxChars. Hence,
- all wxString manipulation in your application will then operate on Unicode
- strings, and almost as easily as working with ordinary char strings (you
- just need to remember to use the wxT() macro to encapsulate any string
- literals).
- But often, your environment doesn't want Unicode strings. You could be sending
- data over a network, or processing a text file for some other application. You
- need a way to quickly convert your easily-handled Unicode data to and from a
- traditional 8-bit encoding. And this is what the wxMBConv classes do.
-
- @section wxmbconvclasses wxMBConv classes
-
- The base class for all these conversions is the wxMBConv class (which itself
- implements standard libc locale conversion). Derived classes include
- wxMBConvLibc, several different wxMBConvUTFxxx classes, and wxCSConv, which
- implement different kinds of conversions. You can also derive your own class
- for your own custom encoding and use it, should you need it. All you need to do
- is override the MB2WC and WC2MB methods.
-
- @section wxmbconvobjects wxMBConv objects
-
- Several of the wxWidgets-provided wxMBConv classes have predefined instances
- (wxConvLibc, wxConvFileName, wxConvUTF7, wxConvUTF8, wxConvLocal). You can use
- these predefined objects directly, or you can instantiate your own objects.
- A variable, wxConvCurrent, points to the conversion object that the user
- interface is supposed to use, in the case that the user interface is not
- Unicode-based (like with GTK+ 1.2). By default, it points to wxConvLibc or
- wxConvLocal, depending on which works best on the current platform.
-
- @section wxcsconvclass wxCSConv
-
- The wxCSConv class is special because when it is instantiated, you can tell it
- which character set it should use, which makes it meaningful to keep many
- instances of them around, each with a different character set (or you can
- create a wxCSConv instance on the fly).
- The predefined wxCSConv instance, wxConvLocal, is preset to use the
- default user character set, but you should rarely need to use it directly,
- it is better to go through wxConvCurrent.
-
- @section convertingstrings Converting strings
-
- Once you have chosen which object you want to use to convert your text,
- here is how you would use them with wxString. These examples all assume
- that you are using a Unicode build of wxWidgets, although they will still
- compile in a non-Unicode build (they just won't convert anything).
- Example 1: Constructing a wxString from input in current encoding.
-
- @code
- wxString str(input_data, *wxConvCurrent);
- @endcode
-
- Example 2: Input in UTF-8 encoding.
-
- @code
- wxString str(input_data, wxConvUTF8);
- @endcode
-
- Example 3: Input in KOI8-R. Construction of wxCSConv instance on the fly.
-
- @code
- wxString str(input_data, wxCSConv(wxT("koi8-r")));
- @endcode
-
- Example 4: Printing a wxString to stdout in UTF-8 encoding.
-
- @code
- puts(str.mb_str(wxConvUTF8));
- @endcode
-
- Example 5: Printing a wxString to stdout in custom encoding.
- Using preconstructed wxCSConv instance.
-
- @code
- wxCSConv cust(user_encoding);
- printf("Data: %s\n", (const char*) str.mb_str(cust));
- @endcode
-
- Note: Since mb_str() returns a temporary wxCharBuffer to hold the result
- of the conversion, you need to explicitly cast it to const char* if you use
- it in a vararg context (like with printf).
-
- @section convertingbuffers Converting buffers
-
- If you have specialized needs, or just don't want to use wxString, you
- can also use the conversion methods of the conversion objects directly.
- This can even be useful if you need to do conversion in a non-Unicode
- build of wxWidgets; converting a string from UTF-8 to the current
- encoding should be possible by doing this:
-
- @code
- wxString str(wxConvUTF8.cMB2WC(input_data), *wxConvCurrent);
- @endcode
-
- Here, cMB2WC of the UTF8 object returns a wxWCharBuffer containing a Unicode
- string. The wxString constructor then converts it back to an 8-bit character
- set using the passed conversion object, *wxConvCurrent. (In a Unicode build
- of wxWidgets, the constructor ignores the passed conversion object and
- retains the Unicode data.)
- This could also be done by first making a wxString of the original data:
-
- @code
- wxString input_str(input_data);
- wxString str(input_str.wc_str(wxConvUTF8), *wxConvCurrent);
- @endcode
-
- To print a wxChar buffer to a non-Unicode stdout:
+/**
- @code
- printf("Data: %s\n", (const char*) wxConvCurrent-cWX2MB(unicode_data));
- @endcode
+@page overview_mbconv wxMBConv Overview
- If you need to do more complex processing on the converted data, you
- may want to store the temporary buffer in a local variable:
+Classes: wxMBConv, wxMBConvLibc, wxMBConvUTF7, wxMBConvUTF8, wxCSConv,
+ wxMBConvUTF16, wxMBConvUTF32
- @code
- const wxWX2MBbuf tmp_buf = wxConvCurrent-cWX2MB(unicode_data);
- const char *tmp_str = (const char*) tmp_buf;
- printf("Data: %s\n", tmp_str);
- process_data(tmp_str);
- @endcode
+The wxMBConv classes in wxWidgets enable an Unicode-aware application to easily
+convert between Unicode and the variety of 8-bit encoding systems still in use.
- If a conversion had taken place in cWX2MB (i.e. in a Unicode build),
- the buffer will be deallocated as soon as tmp_buf goes out of scope.
- (The macro wxWX2MBbuf reflects the correct return value of cWX2MB
- (either char* or wxCharBuffer), except for the const.)
+@li @ref overview_mbconv_need
+@li @ref overview_mbconv_string
+@li @ref overview_mbconv_classes
+@li @ref overview_mbconv_objects
+@li @ref overview_mbconv_csconv
+@li @ref overview_mbconv_converting
+@li @ref overview_mbconv_buffers
- */
+<hr>
+
+
+@section overview_mbconv_need Background: The Need for Conversion
+
+As programs are becoming more and more globalized, and users exchange documents
+across country boundaries as never before, applications increasingly need to
+take into account all the different character sets in use around the world. It
+is no longer enough to just depend on the default byte-sized character set that
+computers have traditionally used.
+
+A few years ago, a solution was proposed: the Unicode standard. Able to contain
+the complete set of characters in use in one unified global coding system, it
+would resolve the character set problems once and for all.
+
+But it hasn't happened yet, and the migration towards Unicode has created new
+challenges, resulting in "compatibility encodings" such as UTF-8. A large
+number of systems out there still depends on the old 8-bit encodings, hampered
+by the huge amounts of legacy code still widely deployed. Even sending Unicode
+data from one Unicode-aware system to another may need encoding to an 8-bit
+multibyte encoding (UTF-7 or UTF-8 is typically used for this purpose), to pass
+unhindered through any traditional transport channels.
+
+
+@section overview_mbconv_string Background: The wxString Class
+
+If you have compiled wxWidgets in Unicode mode, the wxChar type will become
+identical to wchar_t rather than char, and a wxString stores wxChars. Hence,
+all wxString manipulation in your application will then operate on Unicode
+strings, and almost as easily as working with ordinary char strings (you just
+need to remember to use the wxT() macro to encapsulate any string literals).
+
+But often, your environment doesn't want Unicode strings. You could be sending
+data over a network, or processing a text file for some other application. You
+need a way to quickly convert your easily-handled Unicode data to and from a
+traditional 8-bit encoding. And this is what the wxMBConv classes do.
+
+
+@section overview_mbconv_classes wxMBConv Classes
+
+The base class for all these conversions is the wxMBConv class (which itself
+implements standard libc locale conversion). Derived classes include
+wxMBConvLibc, several different wxMBConvUTFxxx classes, and wxCSConv, which
+implement different kinds of conversions. You can also derive your own class
+for your own custom encoding and use it, should you need it. All you need to do
+is override the MB2WC and WC2MB methods.
+
+
+@section overview_mbconv_objects wxMBConv Objects
+
+Several of the wxWidgets-provided wxMBConv classes have predefined instances
+(wxConvLibc, wxConvFileName, wxConvUTF7, wxConvUTF8, wxConvLocal). You can use
+these predefined objects directly, or you can instantiate your own objects.
+
+A variable, wxConvCurrent, points to the conversion object that the user
+interface is supposed to use, in the case that the user interface is not
+Unicode-based (like with GTK+ 1.2). By default, it points to wxConvLibc or
+wxConvLocal, depending on which works best on the current platform.
+
+
+@section overview_mbconv_csconv wxCSConv
+
+The wxCSConv class is special because when it is instantiated, you can tell it
+which character set it should use, which makes it meaningful to keep many
+instances of them around, each with a different character set (or you can
+create a wxCSConv instance on the fly).
+
+The predefined wxCSConv instance, wxConvLocal, is preset to use the default
+user character set, but you should rarely need to use it directly, it is better
+to go through wxConvCurrent.
+
+
+@section overview_mbconv_converting Converting Strings
+
+Once you have chosen which object you want to use to convert your text, here is
+how you would use them with wxString. These examples all assume that you are
+using a Unicode build of wxWidgets, although they will still compile in a
+non-Unicode build (they just won't convert anything).
+
+Example 1: Constructing a wxString from input in current encoding.
+
+@code
+wxString str(input_data, *wxConvCurrent);
+@endcode
+
+Example 2: Input in UTF-8 encoding.
+
+@code
+wxString str(input_data, wxConvUTF8);
+@endcode
+
+Example 3: Input in KOI8-R. Construction of wxCSConv instance on the fly.
+
+@code
+wxString str(input_data, wxCSConv(wxT("koi8-r")));
+@endcode
+
+Example 4: Printing a wxString to stdout in UTF-8 encoding.
+
+@code
+puts(str.mb_str(wxConvUTF8));
+@endcode
+
+Example 5: Printing a wxString to stdout in custom encoding. Using
+preconstructed wxCSConv instance.
+
+@code
+wxCSConv cust(user_encoding);
+printf("Data: %s\n", (const char*) str.mb_str(cust));
+@endcode
+
+@note Since mb_str() returns a temporary wxCharBuffer to hold the result of the
+conversion, you need to explicitly cast it to const char* if you use it in a
+vararg context (like with printf).
+
+
+@section overview_mbconv_buffers Converting Buffers
+
+If you have specialized needs, or just don't want to use wxString, you can also
+use the conversion methods of the conversion objects directly. This can even be
+useful if you need to do conversion in a non-Unicode build of wxWidgets;
+converting a string from UTF-8 to the current encoding should be possible by
+doing this:
+
+@code
+wxString str(wxConvUTF8.cMB2WC(input_data), *wxConvCurrent);
+@endcode
+
+Here, cMB2WC of the UTF8 object returns a wxWCharBuffer containing a Unicode
+string. The wxString constructor then converts it back to an 8-bit character
+set using the passed conversion object, *wxConvCurrent. (In a Unicode build of
+wxWidgets, the constructor ignores the passed conversion object and retains the
+Unicode data.)
+
+This could also be done by first making a wxString of the original data:
+
+@code
+wxString input_str(input_data);
+wxString str(input_str.wc_str(wxConvUTF8), *wxConvCurrent);
+@endcode
+
+To print a wxChar buffer to a non-Unicode stdout:
+
+@code
+printf("Data: %s\n", (const char*) wxConvCurrent->cWX2MB(unicode_data));
+@endcode
+
+If you need to do more complex processing on the converted data, you may want
+to store the temporary buffer in a local variable:
+
+@code
+const wxWX2MBbuf tmp_buf = wxConvCurrent->cWX2MB(unicode_data);
+const char *tmp_str = (const char*) tmp_buf;
+printf("Data: %s\n", tmp_str);
+process_data(tmp_str);
+@endcode
+
+If a conversion had taken place in cWX2MB (i.e. in a Unicode build), the buffer
+will be deallocated as soon as tmp_buf goes out of scope. The macro wxWX2MBbuf
+reflects the correct return value of cWX2MB (either char* or wxCharBuffer),
+except for the const.
+
+*/
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