interface/wx/encconv.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        encconv.h
   3 // Purpose:     interface of wxEncodingConverter
   4 // Author:      wxWidgets team
   5 // RCS-ID:      $Id$
   6 // Licence:     wxWindows licence
   7 /////////////////////////////////////////////////////////////////////////////
   8
   9 /**
  10     @class wxEncodingConverter
  11
  12     This class is capable of converting strings between two 8-bit encodings/charsets.
  13     It can also convert from/to Unicode.
  14
  15     Only a limited subset of encodings is supported by wxEncodingConverter:
  16     @c wxFONTENCODING_ISO8859_1..15, @c wxFONTENCODING_CP1250..1257 and
  17     @c wxFONTENCODING_KOI8.
  18
  19     @note
  20     Please use wxMBConv classes instead if possible. wxCSConv has much better
  21     support for various encodings than wxEncodingConverter.
  22     wxEncodingConverter is useful only if you rely on wxCONVERT_SUBSTITUTE mode
  23     of operation (see wxEncodingConverter::Init()).
  24
  25     @library{wxbase}
  26     @category{conv}
  27
  28     @see wxFontMapper, wxMBConv, @ref overview_nonenglish
  29 */
  30 class wxEncodingConverter : public wxObject
  31 {
  32 public:
  33     /**
  34         Constructor.
  35     */
  36     wxEncodingConverter();
  37
  38     /**
  39         Return @true if (any text in) multibyte encoding @a encIn can be converted to
  40         another one (@a encOut) losslessly.
  41
  42         Do not call this method with @c wxFONTENCODING_UNICODE as either parameter,
  43         it doesn't make sense (always works in one sense and always depends
  44         on the text to convert in the other).
  45     */
  46     static bool CanConvert(wxFontEncoding encIn,
  47                            wxFontEncoding encOut);
  48
  49     /**
  50         @name Conversion functions
  51
  52         @{
  53     */
  54     /**
  55         Convert input string according to settings passed to Init() and writes
  56         the result to output.
  57
  58         All the Convert() function overloads return @true if the conversion was
  59         lossless and @false if at least one of the characters couldn't be converted
  60         was and replaced with '?' in the output.
  61
  62         Note that if @c wxCONVERT_SUBSTITUTE was passed to Init(), substitution is
  63         considered a lossless operation.
  64
  65         @note You must call Init() before using this method!
  66     */
  67     bool Convert(const char* input, char* output) const;
  68     bool Convert(const wchar_t* input, wchar_t* output) const;
  69     bool Convert(const char* input, wchar_t* output) const;
  70     bool Convert(const wchar_t* input, char* output) const;
  71
  72     /**
  73         Convert input string according to settings passed to Init() in-place.
  74
  75         With this overload, the conversion result is written to the same memory
  76         area from which the input is read.
  77
  78         See the Convert(const char*,char*) const overload for more info.
  79     */
  80     bool Convert(char* str) const;
  81
  82     /**
  83         Convert input string according to settings passed to Init() in-place.
  84
  85         With this overload, the conversion result is written to the same memory
  86         area from which the input is read.
  87
  88         See the Convert(const wchar_t*,wchar_t*) const overload for more info.
  89     */
  90     bool Convert(wchar_t* str) const;
  91
  92     /**
  93         Convert a wxString and return a new wxString object.
  94
  95         See the Convert(const char*,char*) const overload for more info.
  96     */
  97     wxString Convert(const wxString& input) const;
  98     //@}
  99
 100
 101     /**
 102         Similar to GetPlatformEquivalents(), but this one will return ALL
 103         equivalent encodings, regardless of the platform, and including itself.
 104
 105         This platform's encodings are before others in the array.
 106         And again, if @a enc is in the array, it is the very first item in it.
 107     */
 108     static wxFontEncodingArray GetAllEquivalents(wxFontEncoding enc);
 109
 110     /**
 111         Return equivalents for given font that are used under given platform.
 112
 113         Supported platforms:
 114         @li wxPLATFORM_UNIX
 115         @li wxPLATFORM_WINDOWS
 116         @li wxPLATFORM_OS2
 117         @li wxPLATFORM_MAC
 118         @li wxPLATFORM_CURRENT
 119
 120         wxPLATFORM_CURRENT means the platform this binary was compiled for.
 121
 122         Examples:
 123
 124         @verbatim
 125         current platform   enc          returned value
 126         ----------------------------------------------
 127         unix            CP1250             {ISO8859_2}
 128         unix         ISO8859_2             {ISO8859_2}
 129         windows      ISO8859_2                {CP1250}
 130         unix            CP1252  {ISO8859_1,ISO8859_15}
 131         @endverbatim
 132
 133         Equivalence is defined in terms of convertibility: two encodings are
 134         equivalent if you can convert text between then without losing
 135         information (it may - and will - happen that you lose special chars
 136         like quotation marks or em-dashes but you shouldn't lose any diacritics
 137         and language-specific characters when converting between equivalent encodings).
 138
 139         Remember that this function does @b NOT check for presence of
 140         fonts in system. It only tells you what are most suitable
 141         encodings. (It usually returns only one encoding.)
 142
 143         @note Note that argument enc itself may be present in the returned array,
 144               so that you can, as a side-effect, detect whether the encoding is
 145               native for this platform or not.
 146
 147         @note Convert() is not limited to converting between equivalent encodings,
 148               it can convert between two arbitrary encodings.
 149
 150         @note If @a enc is present in the returned array, then it is always the first
 151               item of it.
 152
 153         @note Please note that the returned array may contain no items at all.
 154     */
 155     static wxFontEncodingArray GetPlatformEquivalents(wxFontEncoding enc,
 156                                                       int platform = wxPLATFORM_CURRENT);
 157
 158     /**
 159         Initialize the conversion.
 160
 161         Both output or input encoding may be wxFONTENCODING_UNICODE, but only
 162         if wxUSE_ENCODING is set to 1.
 163
 164         All subsequent calls to Convert() will interpret its argument
 165         as a string in @a input_enc encoding and will output string in
 166         @a output_enc encoding.
 167
 168         You must call this method before calling Convert. You may call
 169         it more than once in order to switch to another conversion.
 170
 171         @a method affects behaviour of Convert() in case input character
 172         cannot be converted because it does not exist in output encoding:
 173
 174         @li @b wxCONVERT_STRICT: follow behaviour of GNU Recode - just copy
 175             unconvertible  characters to output and don't change them
 176             (its integer value will stay the same)
 177         @li @b wxCONVERT_SUBSTITUTE:  try some (lossy) substitutions - e.g.
 178             replace unconvertible latin capitals with acute by ordinary
 179             capitals, replace en-dash or em-dash by '-' etc.
 180
 181         Both modes guarantee that output string will have same length
 182         as input string.
 183
 184         @return @false if given conversion is impossible, @true otherwise
 185                 (conversion may be impossible either if you try to convert
 186                 to Unicode with non-Unicode build of wxWidgets or if input
 187                 or output encoding is not supported).
 188     */
 189     bool Init(wxFontEncoding input_enc, wxFontEncoding output_enc,
 190               int method = wxCONVERT_STRICT);
 191 };
 192