interface/wx/strconv.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        strconv.h
   3 // Purpose:     interface of wxMBConvUTF7
   4 // Author:      wxWidgets team
   5 // RCS-ID:      $Id$
   6 // Licence:     wxWindows license
   7 /////////////////////////////////////////////////////////////////////////////
   8
   9 /**
  10     @class wxMBConv
  11
  12     This class is the base class of a hierarchy of classes capable of
  13     converting text strings between multibyte (SBCS or DBCS) encodings and
  14     Unicode.
  15
  16     This is an abstract base class which defines the operations implemented by
  17     all different conversion classes. The derived classes don't add any new
  18     operations of their own (except, possibly, some non-default constructors)
  19     and so you should simply use this class ToWChar() and FromWChar() (or
  20     cMB2WC() and cWC2MB()) methods with the objects of the derived class.
  21
  22     In the documentation for this and related classes please notice that
  23     length of the string refers to the number of characters in the string
  24     not counting the terminating @c NUL, if any. While the size of the string
  25     is the total number of bytes in the string, including any trailing @c NUL.
  26     Thus, length of wide character string @c L"foo" is 3 while its size can
  27     be either 8 or 16 depending on whether @c wchar_t is 2 bytes (as
  28     under Windows) or 4 (Unix).
  29
  30     @library{wxbase}
  31     @category{conv}
  32
  33     @see wxCSConv, wxEncodingConverter, @ref overview_mbconv "wxMBConv classes overview"
  34 */
  35 class wxMBConv
  36 {
  37 public:
  38     /**
  39         Trivial default constructor.
  40     */
  41     wxMBConv();
  42
  43     /**
  44         This pure virtual function is overridden in each of the derived classes
  45         to return a new copy of the object it is called on.
  46
  47         It is used for copying the conversion objects while preserving their
  48         dynamic type.
  49     */
  50     virtual wxMBConv* Clone() const = 0;
  51
  52     /**
  53         This function returns 1 for most of the multibyte encodings in which the
  54         string is terminated by a single @c NUL, 2 for UTF-16 and 4 for UTF-32 for
  55         which the string is terminated with 2 and 4 @c NUL characters respectively.
  56         The other cases are not currently supported and @c wxCONV_FAILED
  57         (defined as -1) is returned for them.
  58     */
  59     size_t GetMBNulLen() const;
  60
  61     /**
  62         Returns the maximal value which can be returned by GetMBNulLen() for
  63         any conversion object.
  64
  65         Currently this value is 4.
  66
  67         This method can be used to allocate the buffer with enough space for the
  68         trailing @c NUL characters for any encoding.
  69     */
  70     const size_t GetMaxMBNulLen();
  71
  72     /**
  73         Convert multibyte string to a wide character one.
  74
  75         This is the most general function for converting a multibyte string to
  76         a wide string, cMB2WC() may be often more convenient, however this
  77         function is the most efficient one as it allows to avoid any
  78         unnecessary copying.
  79
  80         The main case is when @a dst is not @NULL and @a srcLen is not
  81         @c wxNO_LEN (which is defined as @c (size_t)-1): then the function
  82         converts exactly @a srcLen bytes starting at @a src into wide string
  83         which it output to @e dst. If the length of the resulting wide
  84         string is greater than @e dstLen, an error is returned. Note that if
  85         @a srcLen bytes don't include @c NUL characters, the resulting wide
  86         string is not @c NUL-terminated neither.
  87
  88         If @a srcLen is @c wxNO_LEN, the function supposes that the string is
  89         properly (i.e. as necessary for the encoding handled by this
  90         conversion) @c NUL-terminated and converts the entire string, including
  91         any trailing @c NUL bytes. In this case the wide string is also @c
  92         NUL-terminated.
  93
  94         Finally, if @a dst is @NULL, the function returns the length of the
  95         needed buffer.
  96
  97         Example of use of this function:
  98         @code
  99         size_t dstLen = conv.ToWChar(NULL, 0, src);
 100         if ( dstLen == wxCONV_FAILED )
 101             ... handle error ...
 102         wchar_t *dst = new wchar_t[dstLen];
 103         if ( conv.ToWChar(dst, dstLen, src) == wxCONV_FAILED )
 104             ... handle error ...
 105         @endcode
 106
 107         Notice that when passing the explicit source length the output will
 108         @e not be @c NUL terminated if you pass @c strlen(str) as parameter.
 109         Either leave @a srcLen as default @c wxNO_LEN or add one to @c strlen
 110         result if you want the output to be @c NUL terminated.
 111
 112         @param dst
 113             Pointer to output buffer of the size of at least @a dstLen or @NULL.
 114         @param dstLen
 115             Maximal number of characters to be written to the output buffer if
 116             @a dst is non-@NULL, unused otherwise.
 117         @param src
 118             Point to the source string, must not be @NULL.
 119         @param
 120             The number of characters of the source string to convert or @c
 121             wxNO_LEN (default parameter) to convert everything up to and
 122             including the terminating @c NUL character(s).
 123         @return
 124             The number of character written (or which would have been written
 125             if it were non-@NULL) to @a dst or @c wxCONV_FAILED on error.
 126     */
 127     virtual size_t ToWChar(wchar_t* dst, size_t dstLen,
 128                            const char* src,
 129                            size_t srcLen = wxNO_LEN) const;
 130
 131     /**
 132         Converts wide character string to multibyte.
 133
 134         This function has the same semantics as ToWChar() except that it
 135         converts a wide string to multibyte one. As with ToWChar(), it may be
 136         more convenient to use cWC2MB() when working with @c NUL terminated
 137         strings.
 138
 139         @param dst
 140             Pointer to output buffer of the size of at least @a dstLen or @NULL.
 141         @param dstLen
 142             Maximal number of characters to be written to the output buffer if
 143             @a dst is non-@NULL, unused otherwise.
 144         @param src
 145             Point to the source string, must not be @NULL.
 146         @param
 147             The number of characters of the source string to convert or @c
 148             wxNO_LEN (default parameter) to convert everything up to and
 149             including the terminating @c NUL character.
 150         @return
 151             The number of character written (or which would have been written
 152             if it were non-@NULL) to @a dst or @c wxCONV_FAILED on error.
 153     */
 154     virtual size_t FromWChar(char* dst, size_t dstLen,
 155                              const wchar_t* src,
 156                              size_t srcLen = wxNO_LEN) const;
 157
 158     /**
 159         Converts from multibyte encoding to Unicode by calling ToWChar() and
 160         allocating a temporary wxWCharBuffer to hold the result.
 161
 162         This function is a convenient wrapper around ToWChar() as it takes care
 163         of allocating the buffer of the necessary size itself. Its parameters
 164         have the same meaning as for ToWChar(), in particular @a inLen can be
 165         specified explicitly in which case exactly that many characters are
 166         converted and @a outLen receives (if non-@NULL) exactly the
 167         corresponding number of wide characters, whether the last one of them
 168         is @c NUL or not. However if @c inLen is @c wxNO_LEN, then @c outLen
 169         doesn't count the trailing @c NUL even if it is always present in this
 170         case.
 171
 172         Finally notice that if the conversion fails, the returned buffer is
 173         invalid and @a outLen is set to 0 (and not @c wxCONV_FAILED for
 174         compatibility concerns).
 175     */
 176     const wxWCharBuffer cMB2WC(const char* in,
 177                                size_t inLen = wxNO_LEN,
 178                                size_t *outLen = NULL) const;
 179
 180     //@{
 181     /**
 182         Converts from multibyte encoding to the current wxChar type (which
 183         depends on whether wxUSE_UNICODE is set to 1).
 184
 185         If wxChar is char, it returns the parameter unaltered. If wxChar is
 186         wchar_t, it returns the result in a wxWCharBuffer. The macro wxMB2WXbuf
 187         is defined as the correct return type (without const).
 188     */
 189     const char* cMB2WX(const char* psz) const;
 190     const wxWCharBuffer cMB2WX(const char* psz) const;
 191     //@}
 192
 193     /**
 194         Converts from Unicode to multibyte encoding by calling FromWChar() and
 195         allocating a temporary wxCharBuffer to hold the result.
 196
 197         This function is a convenient wrapper around FromWChar() as it takes
 198         care of allocating the buffer of necessary size itself.
 199
 200         Its parameters have the same meaning as the corresponding parameters of
 201         FromWChar(), please see the description of cMB2WC() for more details.
 202     */
 203     const wxCharBuffer cWC2MB(const wchar_t* in,
 204                               size_t inLen = wxNO_LEN,
 205                               size_t *outLen = NULL) const;
 206
 207     //@{
 208     /**
 209         Converts from Unicode to the current wxChar type.
 210
 211         If wxChar is wchar_t, it returns the parameter unaltered. If wxChar is
 212         char, it returns the result in a wxCharBuffer. The macro wxWC2WXbuf is
 213         defined as the correct return type (without const).
 214     */
 215     const wchar_t* cWC2WX(const wchar_t* psz) const;
 216     const wxCharBuffer cWC2WX(const wchar_t* psz) const;
 217     //@}
 218
 219     //@{
 220     /**
 221         Converts from the current wxChar type to multibyte encoding.
 222
 223         If wxChar is char, it returns the parameter unaltered. If wxChar is
 224         wchar_t, it returns the result in a wxCharBuffer. The macro wxWX2MBbuf
 225         is defined as the correct return type (without const).
 226     */
 227     const char* cWX2MB(const wxChar* psz) const;
 228     const wxCharBuffer cWX2MB(const wxChar* psz) const;
 229     //@}
 230
 231     //@{
 232     /**
 233         Converts from the current wxChar type to Unicode.
 234
 235         If wxChar is wchar_t, it returns the parameter unaltered. If wxChar is
 236         char, it returns the result in a wxWCharBuffer. The macro wxWX2WCbuf is
 237         defined as the correct return type (without const).
 238     */
 239     const wchar_t* cWX2WC(const wxChar* psz) const;
 240     const wxWCharBuffer cWX2WC(const wxChar* psz) const;
 241     //@}
 242
 243     /**
 244         @deprecated This function is deprecated, please use ToWChar() instead.
 245
 246         Converts from a string @a in in multibyte encoding to Unicode putting up to
 247         @a outLen characters into the buffer @e out.
 248
 249         If @a out is @NULL, only the length of the string which would result
 250         from the conversion is calculated and returned. Note that this is the
 251         length and not size, i.e. the returned value does not include the
 252         trailing @c NUL. But when the function is called with a non-@NULL @a
 253         out buffer, the @a outLen parameter should be one more to allow to
 254         properly @c NUL-terminate the string.
 255
 256         @param out
 257             The output buffer, may be @NULL if the caller is only
 258             interested in the length of the resulting string
 259         @param in
 260             The NUL-terminated input string, cannot be @NULL
 261         @param outLen
 262             The length of the output buffer but including
 263             NUL, ignored if out is @NULL
 264
 265         @return The length of the converted string excluding the trailing NUL.
 266     */
 267     virtual size_t MB2WC(wchar_t* out, const char* in, size_t outLen) const;
 268
 269     /**
 270         @deprecated This function is deprecated, please use FromWChar() instead.
 271
 272         Converts from Unicode to multibyte encoding.
 273         The semantics of this function (including the return value meaning) is
 274         the same as for wxMBConv::MB2WC. Notice that when the function is
 275         called with a non-@NULL buffer, the @a n parameter should be the size
 276         of the buffer and so it should take into account the trailing @c NUL,
 277         which might take two or four bytes for some encodings (UTF-16 and
 278         UTF-32) and not one.
 279     */
 280     virtual size_t WC2MB(char* buf, const wchar_t* psz, size_t n) const;
 281 };
 282
 283
 284 /**
 285     @class wxMBConvUTF7
 286
 287     This class converts between the UTF-7 encoding and Unicode.
 288     It has one predefined instance, @b wxConvUTF7.
 289
 290     Notice that, unlike all the other conversion objects, this converter is
 291     stateful, i.e. it remembers its state from the last call to its ToWChar()
 292     or FromWChar() and assumes it is called on the continuation of the same
 293     string when the same method is called again. This assumption is only made
 294     if an explicit length is specified as parameter to these functions as if an
 295     entire @c NUL terminated string is processed the state doesn't need to be
 296     remembered.
 297
 298     This also means that, unlike the other predefined conversion objects,
 299     @b wxConvUTF7 is @em not thread-safe.
 300
 301     @library{wxbase}
 302     @category{conv}
 303
 304     @see wxMBConvUTF8, @ref overview_mbconv "wxMBConv classes overview"
 305 */
 306 class wxMBConvUTF7 : public wxMBConv
 307 {
 308 };
 309
 310
 311
 312 /**
 313     @class wxMBConvUTF8
 314
 315     This class converts between the UTF-8 encoding and Unicode.
 316     It has one predefined instance, @b wxConvUTF8.
 317
 318     @library{wxbase}
 319     @category{conv}
 320
 321     @see wxMBConvUTF7, @ref overview_mbconv "wxMBConv classes overview"
 322 */
 323 class wxMBConvUTF8 : public wxMBConv
 324 {
 325 };
 326
 327
 328
 329 /**
 330     @class wxMBConvUTF16
 331
 332     This class is used to convert between multibyte encodings and UTF-16 Unicode
 333     encoding (also known as UCS-2).
 334
 335     Unlike UTF-8 encoding, UTF-16 uses words and not bytes and hence depends
 336     on the byte ordering: big or little endian. Hence this class is provided in
 337     two versions: wxMBConvUTF16LE and wxMBConvUTF16BE and wxMBConvUTF16 itself
 338     is just a typedef for one of them (native for the given platform, e.g. LE
 339     under Windows and BE under Mac).
 340
 341     @library{wxbase}
 342     @category{conv}
 343
 344     @see wxMBConvUTF8, wxMBConvUTF32, @ref overview_mbconv "wxMBConv classes overview"
 345 */
 346 class wxMBConvUTF16 : public wxMBConv
 347 {
 348 };
 349
 350
 351 /**
 352     @class wxMBConvUTF32
 353
 354     This class is used to convert between multibyte encodings and UTF-32
 355     Unicode encoding (also known as UCS-4).
 356     Unlike UTF-8 encoding, UTF-32 uses (double) words and not bytes and hence
 357     depends on the byte ordering: big or little endian. Hence this class is
 358     provided in two versions: wxMBConvUTF32LE and wxMBConvUTF32BE and
 359     wxMBConvUTF32 itself is just a typedef for one of them (native for the
 360     given platform, e.g. LE under Windows and BE under Mac).
 361
 362     @library{wxbase}
 363     @category{conv}
 364
 365     @see wxMBConvUTF8, wxMBConvUTF16, @ref overview_mbconv "wxMBConv classes overview"
 366 */
 367 class wxMBConvUTF32 : public wxMBConv
 368 {
 369 };
 370
 371
 372
 373
 374 /**
 375     @class wxCSConv
 376
 377     This class converts between any character set supported by the system and
 378     Unicode.
 379
 380     Please notice that this class uses system-provided conversion functions,
 381     e.g. @c MultiByteToWideChar() and @c WideCharToMultiByte() under MSW and @c
 382     iconv(3) under Unix systems and as such may support different encodings and
 383     different encoding names on different platforms (although all relatively
 384     common encodings are supported should be supported everywhere).
 385
 386     It has one predefined instance, @b wxConvLocal, for the default user
 387     character set.
 388
 389     @library{wxbase}
 390     @category{conv}
 391
 392     @see wxMBConv, wxEncodingConverter, @ref overview_mbconv "wxMBConv classes overview"
 393 */
 394 class wxCSConv : public wxMBConv
 395 {
 396 public:
 397     /**
 398         Constructor.
 399
 400         You can specify the name of the character set you want to convert
 401         from/to. If the character set name is not recognized, ISO 8859-1 is
 402         used as fall back, use IsOk() to test for this.
 403
 404         @param charset The name of the encoding, shouldn't be empty.
 405     */
 406     wxCSConv(const wxString& charset);
 407
 408     /**
 409         Constructor.
 410
 411         You can specify an encoding constant for the character set you want to
 412         convert from/to. Use IsOk() after construction to check whether the
 413         encoding is supported by the current system.
 414
 415         @param encoding Any valid (i.e. not wxFONTENCODING_MAX) font encoding.
 416     */
 417     wxCSConv(wxFontEncoding encoding);
 418
 419     /**
 420         Returns @true if the charset (or the encoding) given at constructor is
 421         really available to use.
 422
 423         Returns @false if ISO 8859-1 will be used instead.
 424
 425         Note this does not mean that a given string will be correctly
 426         converted. A malformed string may still make conversion functions
 427         return @c wxCONV_FAILED.
 428
 429         @since 2.8.2
 430     */
 431     bool IsOk() const;
 432 };
 433
 434
 435
 436 /**
 437     @class wxMBConvFile
 438
 439     This class used to define the class instance @b wxConvFileName, but
 440     nowadays @b wxConvFileName is either of type wxConvLibc (on most platforms)
 441     or wxConvUTF8 (on MacOS X).
 442
 443     @b wxConvFileName converts filenames between filesystem multibyte encoding
 444     and Unicode. @b wxConvFileName can also be set to a something else at
 445     run-time which is used e.g. by wxGTK to use a class which checks the
 446     environment variable @b G_FILESYSTEM_ENCODING indicating that filenames
 447     should not be interpreted as UTF8 and also for converting invalid UTF8
 448     characters (e.g. if there is a filename in iso8859_1) to strings with octal
 449     values.
 450
 451     Since some platforms (such as Win32) use Unicode in the filenames,
 452     and others (such as Unix) use multibyte encodings, this class should only
 453     be used directly if wxMBFILES is defined to 1. A convenience macro,
 454     @c wxFNCONV, is defined to @c wxConvFileName->cWX2MB in this case. You
 455     could use it like this:
 456
 457     @code
 458     wxChar *name = wxT("rawfile.doc");
 459     FILE *fil = fopen(wxFNCONV(name), "r");
 460     @endcode
 461
 462     (although it would be better to just use wxFopen(name, "r") in this
 463     particular case, you only need to use this class for functions taking file
 464     names not wrapped by wxWidgets.)
 465
 466     @library{wxbase}
 467     @category{conv}
 468
 469     @see @ref overview_mbconv "wxMBConv classes overview"
 470 */
 471 class wxMBConvFile : public wxMBConv
 472 {
 473 public:
 474 };