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
  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     virtual 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     static 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 srcLen
 120             The number of characters of the source string to convert or
 121             @c wxNO_LEN (default parameter) to convert everything up to and
 122             including the terminating @c NUL character(s).
 123
 124         @return
 125             The number of character written (or which would have been written
 126             if it were non-@NULL) to @a dst or @c wxCONV_FAILED on error.
 127     */
 128     virtual size_t ToWChar(wchar_t* dst, size_t dstLen, 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 srcLen
 147             The number of characters of the source string to convert or
 148             @c wxNO_LEN (default parameter) to convert everything up to and
 149             including the terminating @c NUL character.
 150
 151         @return
 152             The number of character written (or which would have been written
 153             if it were non-@NULL) to @a dst or @c wxCONV_FAILED on error.
 154     */
 155     virtual size_t FromWChar(char* dst, size_t dstLen, 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         So to properly use this function you need to write:
 257         @code
 258             size_t lenConv = conv.MB2WC(NULL, in, 0);
 259             if ( lenConv == wxCONV_FAILED )
 260                 ... handle error ...
 261             // allocate 1 more character for the trailing NUL and also pass
 262             // the size of the buffer to the function now
 263             wchar_t *out = new wchar_t[lenConv + 1];
 264             if ( conv.MB2WC(out, in, lenConv + 1) == wxCONV_FAILED )
 265                 ... handle error ...
 266         @endcode
 267         For this and other reasons, ToWChar() is strongly recommended as a
 268         replacement.
 269
 270         @param out
 271             The output buffer, may be @NULL if the caller is only
 272             interested in the length of the resulting string
 273         @param in
 274             The NUL-terminated input string, cannot be @NULL
 275         @param outLen
 276             The length of the output buffer but including
 277             NUL, ignored if out is @NULL
 278
 279         @return The length of the converted string excluding the trailing NUL.
 280     */
 281     virtual size_t MB2WC(wchar_t* out, const char* in, size_t outLen) const;
 282
 283     /**
 284         @deprecated This function is deprecated, please use FromWChar() instead.
 285
 286         Converts from Unicode to multibyte encoding.
 287         The semantics of this function (including the return value meaning) is
 288         the same as for wxMBConv::MB2WC. Notice that when the function is
 289         called with a non-@NULL buffer, the @a n parameter should be the size
 290         of the buffer and so it should take into account the trailing @c NUL,
 291         which might take two or four bytes for some encodings (UTF-16 and
 292         UTF-32) and not one, i.e. GetMBNulLen().
 293     */
 294     virtual size_t WC2MB(char* buf, const wchar_t* psz, size_t n) const;
 295 };
 296
 297
 298 /**
 299     @class wxMBConvUTF7
 300
 301     This class converts between the UTF-7 encoding and Unicode.
 302     It has one predefined instance, @b wxConvUTF7.
 303
 304     Notice that, unlike all the other conversion objects, this converter is
 305     stateful, i.e. it remembers its state from the last call to its ToWChar()
 306     or FromWChar() and assumes it is called on the continuation of the same
 307     string when the same method is called again. This assumption is only made
 308     if an explicit length is specified as parameter to these functions as if an
 309     entire @c NUL terminated string is processed the state doesn't need to be
 310     remembered.
 311
 312     This also means that, unlike the other predefined conversion objects,
 313     @b wxConvUTF7 is @em not thread-safe.
 314
 315     @library{wxbase}
 316     @category{conv}
 317
 318     @see wxMBConvUTF8, @ref overview_mbconv
 319 */
 320 class wxMBConvUTF7 : public wxMBConv
 321 {
 322 };
 323
 324
 325
 326 /**
 327     @class wxMBConvUTF8
 328
 329     This class converts between the UTF-8 encoding and Unicode.
 330     It has one predefined instance, @b wxConvUTF8.
 331
 332     @library{wxbase}
 333     @category{conv}
 334
 335     @see wxMBConvUTF7, @ref overview_mbconv
 336 */
 337 class wxMBConvUTF8 : public wxMBConv
 338 {
 339 };
 340
 341
 342
 343 /**
 344     @class wxMBConvUTF16
 345
 346     This class is used to convert between multibyte encodings and UTF-16 Unicode
 347     encoding (also known as UCS-2).
 348
 349     Unlike UTF-8 encoding, UTF-16 uses words and not bytes and hence depends
 350     on the byte ordering: big or little endian. Hence this class is provided in
 351     two versions: wxMBConvUTF16LE and wxMBConvUTF16BE and wxMBConvUTF16 itself
 352     is just a typedef for one of them (native for the given platform, e.g. LE
 353     under Windows and BE under Mac).
 354
 355     @library{wxbase}
 356     @category{conv}
 357
 358     @see wxMBConvUTF8, wxMBConvUTF32, @ref overview_mbconv
 359 */
 360 class wxMBConvUTF16 : public wxMBConv
 361 {
 362 };
 363
 364
 365 /**
 366     @class wxMBConvUTF32
 367
 368     This class is used to convert between multibyte encodings and UTF-32
 369     Unicode encoding (also known as UCS-4).
 370     Unlike UTF-8 encoding, UTF-32 uses (double) words and not bytes and hence
 371     depends on the byte ordering: big or little endian. Hence this class is
 372     provided in two versions: wxMBConvUTF32LE and wxMBConvUTF32BE and
 373     wxMBConvUTF32 itself is just a typedef for one of them (native for the
 374     given platform, e.g. LE under Windows and BE under Mac).
 375
 376     @library{wxbase}
 377     @category{conv}
 378
 379     @see wxMBConvUTF8, wxMBConvUTF16, @ref overview_mbconv
 380 */
 381 class wxMBConvUTF32 : public wxMBConv
 382 {
 383 };
 384
 385
 386
 387
 388 /**
 389     @class wxCSConv
 390
 391     This class converts between any character set supported by the system and
 392     Unicode.
 393
 394     Please notice that this class uses system-provided conversion functions,
 395     e.g. @c MultiByteToWideChar() and @c WideCharToMultiByte() under MSW and @c
 396     iconv(3) under Unix systems and as such may support different encodings and
 397     different encoding names on different platforms (although all relatively
 398     common encodings are supported should be supported everywhere).
 399
 400     It has one predefined instance, @b wxConvLocal, for the default user
 401     character set.
 402
 403     @library{wxbase}
 404     @category{conv}
 405
 406     @see wxMBConv, wxEncodingConverter, @ref overview_mbconv
 407 */
 408 class wxCSConv : public wxMBConv
 409 {
 410 public:
 411     /**
 412         Constructor.
 413
 414         You can specify the name of the character set you want to convert
 415         from/to. If the character set name is not recognized, ISO 8859-1 is
 416         used as fall back, use IsOk() to test for this.
 417
 418         @param charset The name of the encoding, shouldn't be empty.
 419     */
 420     wxCSConv(const wxString& charset);
 421
 422     /**
 423         Constructor.
 424
 425         You can specify an encoding constant for the character set you want to
 426         convert from/to. Use IsOk() after construction to check whether the
 427         encoding is supported by the current system.
 428
 429         @param encoding Any valid (i.e. not wxFONTENCODING_MAX) font encoding.
 430     */
 431     wxCSConv(wxFontEncoding encoding);
 432
 433     /**
 434         Returns @true if the charset (or the encoding) given at constructor is
 435         really available to use.
 436
 437         Returns @false if ISO 8859-1 will be used instead.
 438
 439         Note this does not mean that a given string will be correctly
 440         converted. A malformed string may still make conversion functions
 441         return @c wxCONV_FAILED.
 442
 443         @since 2.8.2
 444     */
 445     bool IsOk() const;
 446 };
 447
 448
 449
 450 /**
 451     @class wxMBConvFile
 452
 453     This class used to define the class instance @b wxConvFileName, but
 454     nowadays @b wxConvFileName is either of type wxConvLibc (on most platforms)
 455     or wxConvUTF8 (on MacOS X).
 456
 457     @b wxConvFileName converts filenames between filesystem multibyte encoding
 458     and Unicode. @b wxConvFileName can also be set to a something else at
 459     run-time which is used e.g. by wxGTK to use a class which checks the
 460     environment variable @b G_FILESYSTEM_ENCODING indicating that filenames
 461     should not be interpreted as UTF8 and also for converting invalid UTF8
 462     characters (e.g. if there is a filename in iso8859_1) to strings with octal
 463     values.
 464
 465     Since some platforms (such as Win32) use Unicode in the filenames,
 466     and others (such as Unix) use multibyte encodings, this class should only
 467     be used directly if wxMBFILES is defined to 1. A convenience macro,
 468     @c wxFNCONV, is defined to @c wxConvFileName->cWX2MB in this case. You
 469     could use it like this:
 470
 471     @code
 472     wxChar *name = wxT("rawfile.doc");
 473     FILE *fil = fopen(wxFNCONV(name), "r");
 474     @endcode
 475
 476     (although it would be better to just use wxFopen(name, "r") in this
 477     particular case, you only need to use this class for functions taking file
 478     names not wrapped by wxWidgets.)
 479
 480     @library{wxbase}
 481     @category{conv}
 482
 483     @see @ref overview_mbconv
 484 */
 485 class wxMBConvFile : public wxMBConv
 486 {
 487 public:
 488 };