include/wx/strvararg.h

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        wx/strvararg.h
   3 // Purpose:     macros for implementing type-safe vararg passing of strings
   4 // Author:      Vaclav Slavik
   5 // Created:     2007-02-19
   6 // RCS-ID:      $Id$
   7 // Copyright:   (c) 2007 REA Elektronik GmbH
   8 // Licence:     wxWindows licence
   9 ///////////////////////////////////////////////////////////////////////////////
  10
  11 #ifndef _WX_STRVARARG_H_
  12 #define _WX_STRVARARG_H_
  13
  14 #include "wx/platform.h"
  15 #if wxONLY_WATCOM_EARLIER_THAN(1,4)
  16     #error "OpenWatcom version >= 1.4 is required to compile this code"
  17 #endif
  18
  19 #include "wx/chartype.h"
  20
  21 class WXDLLIMPEXP_BASE wxCStrData;
  22 class WXDLLIMPEXP_BASE wxString;
  23 class WXDLLIMPEXP_BASE wxCharBuffer;
  24 class WXDLLIMPEXP_BASE wxWCharBuffer;
  25
  26
  27 // ----------------------------------------------------------------------------
  28 // WX_DEFINE_VARARG_FUNC* macros
  29 // ----------------------------------------------------------------------------
  30
  31 // This macro is used to implement type-safe wrappers for variadic functions
  32 // that accept strings as arguments. This makes it possible to pass char*,
  33 // wchar_t* or even wxString (as opposed to having to use wxString::c_str())
  34 // to e.g. wxPrintf().
  35 //
  36 // This is done by defining a set of N template function taking 1..N arguments
  37 // (currently, N is set to 30 in this header). These functions are just thin
  38 // wrappers around another variadic function (@a impl) and the only thing
  39 // the wrapper does is that it normalizes the arguments passed in so that
  40 // they are of the type expected by variadic functions taking string
  41 // arguments, i.e., char* or wchar_t*, depending on the build:
  42 //   * char* in the current locale's charset in ANSI build
  43 //   * whchar_t* in the Unicode build
  44 //
  45 // Parameters:
  46 //        rettype   Functions' return type.
  47 //        name      Name of the function.
  48 //        impl      Name of the variadic function that implements 'name'.
  49 #define WX_DEFINE_VARARG_FUNC(rettype, name, impl)                        \
  50         _WX_VARARG_ITER(_WX_VARARG_MAX_ARGS,                              \
  51                         _WX_VARARG_DEFINE_FUNC,                           \
  52                         rettype, name, impl)
  53
  54 // Like WX_DEFINE_VARARG_FUNC, but for variadic functions that don't return
  55 // a value.
  56 #define WX_DEFINE_VARARG_FUNC_VOID(name, impl)                            \
  57         _WX_VARARG_ITER(_WX_VARARG_MAX_ARGS,                              \
  58                         _WX_VARARG_DEFINE_FUNC_VOID,                      \
  59                         void, name, impl)
  60
  61 // Like WX_DEFINE_VARARG_FUNC_VOID, but instead of wrapping an implementation
  62 // function, does nothing in defined functions' bodies.
  63 //
  64 // Used to implement wxLogXXX functions if wxUSE_LOG=0.
  65 #define WX_DEFINE_VARARG_FUNC_NOP(name)                                   \
  66         _WX_VARARG_ITER(_WX_VARARG_MAX_ARGS,                              \
  67                         _WX_VARARG_DEFINE_FUNC_NOP,                       \
  68                         void, name, dummy)
  69
  70 // ----------------------------------------------------------------------------
  71 // implementation
  72 // ----------------------------------------------------------------------------
  73
  74 // Converts an argument passed to wxPrint etc. into standard form expected,
  75 // by wxXXX functions, e.g. all strings (wxString, char*, wchar_t*) are
  76 // converted into wchar_t* or char* depending on the build.
  77 template<typename T>
  78 struct wxArgNormalizer
  79 {
  80     wxArgNormalizer(const T& value) : m_value(value) {}
  81
  82     // Returns the value in a form that can be safely passed to real vararg
  83     // functions. In case of strings, this is char* in ANSI build and wchar_t*
  84     // in Unicode build.
  85     const T& get() const { return m_value; }
  86
  87     const T& m_value;
  88 };
  89
  90 // special cases for converting strings:
  91
  92 template<>
  93 struct WXDLLIMPEXP_BASE wxArgNormalizer<const wxCStrData&>
  94 {
  95     wxArgNormalizer(const wxCStrData& value) : m_value(value) {}
  96     const wxStringCharType *get() const;
  97
  98     const wxCStrData& m_value;
  99 };
 100
 101 template<>
 102 struct wxArgNormalizer<wxCStrData> : public wxArgNormalizer<const wxCStrData&>
 103 {
 104     wxArgNormalizer(const wxCStrData& value)
 105         : wxArgNormalizer<const wxCStrData&>(value) {}
 106 };
 107
 108 template<>
 109 struct WXDLLIMPEXP_BASE wxArgNormalizer<const wxString&>
 110 {
 111     wxArgNormalizer(const wxString& value) : m_value(value) {}
 112     const wxStringCharType *get() const;
 113
 114     const wxString& m_value;
 115 };
 116
 117 template<>
 118 struct wxArgNormalizer<wxString> : public wxArgNormalizer<const wxString&>
 119 {
 120     wxArgNormalizer(const wxString& value)
 121         : wxArgNormalizer<const wxString&>(value) {}
 122 };
 123
 124 #if wxUSE_UNICODE_WCHAR
 125
 126 template<>
 127 struct WXDLLIMPEXP_BASE wxArgNormalizer<const char*>
 128 {
 129     wxArgNormalizer(const char *value);
 130     ~wxArgNormalizer();
 131     const wchar_t *get() const;
 132
 133     wxWCharBuffer *m_value;
 134 };
 135
 136 template<>
 137 struct wxArgNormalizer<char*> : public wxArgNormalizer<const char*>
 138 {
 139     wxArgNormalizer(char *value)
 140         : wxArgNormalizer<const char*>(value) {}
 141 };
 142
 143 #elif wxUSE_WCHAR_T // !wxUSE_UNICODE_WCHAR && wxUSE_WCHAR_T
 144
 145 template<>
 146 struct WXDLLIMPEXP_BASE wxArgNormalizer<const wchar_t*>
 147 {
 148     wxArgNormalizer(const wchar_t *value);
 149     ~wxArgNormalizer();
 150     const char *get() const;
 151
 152     wxCharBuffer *m_value;
 153 };
 154
 155 template<>
 156 struct wxArgNormalizer<wchar_t*> : public wxArgNormalizer<const wchar_t*>
 157 {
 158     wxArgNormalizer(wchar_t *value)
 159         : wxArgNormalizer<const wchar_t*>(value) {}
 160 };
 161
 162 #endif // wxUSE_UNICODE_WCHAR / !wxUSE_UNICODE_WCHAR && wxUSE_WCHAR_T
 163
 164 // NB: The vararg emulation code is limited to 30 arguments at the moment.
 165 //     If you need more, you need to
 166 //        1) increase the value of _WX_VARARG_MAX_ARGS
 167 //        2) add _WX_VARARG_JOIN_* and _WX_VARARG_ITER_* up to the new
 168 //           _WX_VARARG_MAX_ARGS value to the lists below
 169 #define _WX_VARARG_MAX_ARGS        30
 170
 171 #define _WX_VARARG_JOIN_1(m)                                 m(1)
 172 #define _WX_VARARG_JOIN_2(m)       _WX_VARARG_JOIN_1(m),     m(2)
 173 #define _WX_VARARG_JOIN_3(m)       _WX_VARARG_JOIN_2(m),     m(3)
 174 #define _WX_VARARG_JOIN_4(m)       _WX_VARARG_JOIN_3(m),     m(4)
 175 #define _WX_VARARG_JOIN_5(m)       _WX_VARARG_JOIN_4(m),     m(5)
 176 #define _WX_VARARG_JOIN_6(m)       _WX_VARARG_JOIN_5(m),     m(6)
 177 #define _WX_VARARG_JOIN_7(m)       _WX_VARARG_JOIN_6(m),     m(7)
 178 #define _WX_VARARG_JOIN_8(m)       _WX_VARARG_JOIN_7(m),     m(8)
 179 #define _WX_VARARG_JOIN_9(m)       _WX_VARARG_JOIN_8(m),     m(9)
 180 #define _WX_VARARG_JOIN_10(m)      _WX_VARARG_JOIN_9(m),     m(10)
 181 #define _WX_VARARG_JOIN_11(m)      _WX_VARARG_JOIN_10(m),    m(11)
 182 #define _WX_VARARG_JOIN_12(m)      _WX_VARARG_JOIN_11(m),    m(12)
 183 #define _WX_VARARG_JOIN_13(m)      _WX_VARARG_JOIN_12(m),    m(13)
 184 #define _WX_VARARG_JOIN_14(m)      _WX_VARARG_JOIN_13(m),    m(14)
 185 #define _WX_VARARG_JOIN_15(m)      _WX_VARARG_JOIN_14(m),    m(15)
 186 #define _WX_VARARG_JOIN_16(m)      _WX_VARARG_JOIN_15(m),    m(16)
 187 #define _WX_VARARG_JOIN_17(m)      _WX_VARARG_JOIN_16(m),    m(17)
 188 #define _WX_VARARG_JOIN_18(m)      _WX_VARARG_JOIN_17(m),    m(18)
 189 #define _WX_VARARG_JOIN_19(m)      _WX_VARARG_JOIN_18(m),    m(19)
 190 #define _WX_VARARG_JOIN_20(m)      _WX_VARARG_JOIN_19(m),    m(20)
 191 #define _WX_VARARG_JOIN_21(m)      _WX_VARARG_JOIN_20(m),    m(21)
 192 #define _WX_VARARG_JOIN_22(m)      _WX_VARARG_JOIN_21(m),    m(22)
 193 #define _WX_VARARG_JOIN_23(m)      _WX_VARARG_JOIN_22(m),    m(23)
 194 #define _WX_VARARG_JOIN_24(m)      _WX_VARARG_JOIN_23(m),    m(24)
 195 #define _WX_VARARG_JOIN_25(m)      _WX_VARARG_JOIN_24(m),    m(25)
 196 #define _WX_VARARG_JOIN_26(m)      _WX_VARARG_JOIN_25(m),    m(26)
 197 #define _WX_VARARG_JOIN_27(m)      _WX_VARARG_JOIN_26(m),    m(27)
 198 #define _WX_VARARG_JOIN_28(m)      _WX_VARARG_JOIN_27(m),    m(28)
 199 #define _WX_VARARG_JOIN_29(m)      _WX_VARARG_JOIN_28(m),    m(29)
 200 #define _WX_VARARG_JOIN_30(m)      _WX_VARARG_JOIN_29(m),    m(30)
 201
 202 #define _WX_VARARG_ITER_1(m,a,b,c)                               m(1,a,b,c)
 203 #define _WX_VARARG_ITER_2(m,a,b,c)   _WX_VARARG_ITER_1(m,a,b,c)  m(2,a,b,c)
 204 #define _WX_VARARG_ITER_3(m,a,b,c)   _WX_VARARG_ITER_2(m,a,b,c)  m(3,a,b,c)
 205 #define _WX_VARARG_ITER_4(m,a,b,c)   _WX_VARARG_ITER_3(m,a,b,c)  m(4,a,b,c)
 206 #define _WX_VARARG_ITER_5(m,a,b,c)   _WX_VARARG_ITER_4(m,a,b,c)  m(5,a,b,c)
 207 #define _WX_VARARG_ITER_6(m,a,b,c)   _WX_VARARG_ITER_5(m,a,b,c)  m(6,a,b,c)
 208 #define _WX_VARARG_ITER_7(m,a,b,c)   _WX_VARARG_ITER_6(m,a,b,c)  m(7,a,b,c)
 209 #define _WX_VARARG_ITER_8(m,a,b,c)   _WX_VARARG_ITER_7(m,a,b,c)  m(8,a,b,c)
 210 #define _WX_VARARG_ITER_9(m,a,b,c)   _WX_VARARG_ITER_8(m,a,b,c)  m(9,a,b,c)
 211 #define _WX_VARARG_ITER_10(m,a,b,c)  _WX_VARARG_ITER_9(m,a,b,c)  m(10,a,b,c)
 212 #define _WX_VARARG_ITER_11(m,a,b,c)  _WX_VARARG_ITER_10(m,a,b,c) m(11,a,b,c)
 213 #define _WX_VARARG_ITER_12(m,a,b,c)  _WX_VARARG_ITER_11(m,a,b,c) m(12,a,b,c)
 214 #define _WX_VARARG_ITER_13(m,a,b,c)  _WX_VARARG_ITER_12(m,a,b,c) m(13,a,b,c)
 215 #define _WX_VARARG_ITER_14(m,a,b,c)  _WX_VARARG_ITER_13(m,a,b,c) m(14,a,b,c)
 216 #define _WX_VARARG_ITER_15(m,a,b,c)  _WX_VARARG_ITER_14(m,a,b,c) m(15,a,b,c)
 217 #define _WX_VARARG_ITER_16(m,a,b,c)  _WX_VARARG_ITER_15(m,a,b,c) m(16,a,b,c)
 218 #define _WX_VARARG_ITER_17(m,a,b,c)  _WX_VARARG_ITER_16(m,a,b,c) m(17,a,b,c)
 219 #define _WX_VARARG_ITER_18(m,a,b,c)  _WX_VARARG_ITER_17(m,a,b,c) m(18,a,b,c)
 220 #define _WX_VARARG_ITER_19(m,a,b,c)  _WX_VARARG_ITER_18(m,a,b,c) m(19,a,b,c)
 221 #define _WX_VARARG_ITER_20(m,a,b,c)  _WX_VARARG_ITER_19(m,a,b,c) m(20,a,b,c)
 222 #define _WX_VARARG_ITER_21(m,a,b,c)  _WX_VARARG_ITER_20(m,a,b,c) m(21,a,b,c)
 223 #define _WX_VARARG_ITER_22(m,a,b,c)  _WX_VARARG_ITER_21(m,a,b,c) m(22,a,b,c)
 224 #define _WX_VARARG_ITER_23(m,a,b,c)  _WX_VARARG_ITER_22(m,a,b,c) m(23,a,b,c)
 225 #define _WX_VARARG_ITER_24(m,a,b,c)  _WX_VARARG_ITER_23(m,a,b,c) m(24,a,b,c)
 226 #define _WX_VARARG_ITER_25(m,a,b,c)  _WX_VARARG_ITER_24(m,a,b,c) m(25,a,b,c)
 227 #define _WX_VARARG_ITER_26(m,a,b,c)  _WX_VARARG_ITER_25(m,a,b,c) m(26,a,b,c)
 228 #define _WX_VARARG_ITER_27(m,a,b,c)  _WX_VARARG_ITER_26(m,a,b,c) m(27,a,b,c)
 229 #define _WX_VARARG_ITER_28(m,a,b,c)  _WX_VARARG_ITER_27(m,a,b,c) m(28,a,b,c)
 230 #define _WX_VARARG_ITER_29(m,a,b,c)  _WX_VARARG_ITER_28(m,a,b,c) m(29,a,b,c)
 231 #define _WX_VARARG_ITER_30(m,a,b,c)  _WX_VARARG_ITER_29(m,a,b,c) m(30,a,b,c)
 232
 233 // This macro calls another macro 'm' passed as second argument 'N' times,
 234 // with its only argument set to 1..N, and concatenates the results using
 235 // comma as separator.
 236 //
 237 // An example:
 238 //     #define foo(i)  x##i
 239 //     // this expands to "x1,x2,x3,x4"
 240 //     _WX_VARARG_JOIN(4, foo)
 241 //
 242 //
 243 // N must not be greater than _WX_VARARG_MAX_ARGS (=30).
 244 #define _WX_VARARG_JOIN(N, m)             _WX_VARARG_JOIN_IMPL(N, m)
 245 #define _WX_VARARG_JOIN_IMPL(N, m)        _WX_VARARG_JOIN_##N(m)
 246
 247 // This macro calls another macro 'm' passed as second argument 'N' times, with
 248 // its first argument set to 1..N and the remaining arguments set to 'a', 'b'
 249 // and 'c'. The results are separated with whitespace in the expansion.
 250 //
 251 // An example:
 252 //     // this macro expands to:
 253 //     //     foo(1,a,b,c)
 254 //     //     foo(2,a,b,c)
 255 //     //     foo(3,a,b,c)
 256 //     _WX_VARARG_ITER(3, foo, a, b, c)
 257 //
 258 // N must not be greater than _WX_VARARG_MAX_ARGS (=30).
 259 #define _WX_VARARG_ITER(N, m,a,b,c)       _WX_VARARG_ITER_IMPL(N, m, a, b, c)
 260 #define _WX_VARARG_ITER_IMPL(N, m,a,b,c)  _WX_VARARG_ITER_##N(m, a, b, c)
 261
 262 // Generates code snippet for i-th argument in vararg function's prototype.
 263 #define _WX_VARARG_ARG(i)          T##i a##i
 264
 265 // Like _WX_VARARG_ARG_UNUSED, but outputs argument's type with WXUNUSED.
 266 #define _WX_VARARG_ARG_UNUSED(i)   T##i WXUNUSED(a##i)
 267
 268 // Generates code snippet for i-th type in vararg function's template<...>.
 269 #define _WX_VARARG_TEMPL(i)        typename T##i
 270
 271 // Generates code snippet for passing i-th argument of vararg function
 272 // wrapper to its implementation, normalizing it in the process
 273 #define _WX_VARARG_PASS(i)         wxArgNormalizer<T##i>(a##i).get()
 274
 275
 276 // Macro to be used with _WX_VARARG_ITER in the implementation of
 277 // WX_DEFINE_VARARG_FUNC (see its documentation for the meaning of arguments)
 278 #define _WX_VARARG_DEFINE_FUNC(N, rettype, name, impl)                      \
 279     template<_WX_VARARG_JOIN(N, _WX_VARARG_TEMPL)>                          \
 280     rettype name(_WX_VARARG_JOIN(N, _WX_VARARG_ARG))                        \
 281     {                                                                       \
 282         return impl(_WX_VARARG_JOIN(N, _WX_VARARG_PASS));                   \
 283     }
 284
 285 // Macro to be used with _WX_VARARG_ITER in the implementation of
 286 // WX_DEFINE_VARARG_FUNC_VOID (see its documentation for the meaning of
 287 // arguments; rettype is ignored and is used only to satisfy _WX_VARARG_ITER's
 288 // requirements).
 289 #define _WX_VARARG_DEFINE_FUNC_VOID(N, rettype, name, impl)                 \
 290     template<_WX_VARARG_JOIN(N, _WX_VARARG_TEMPL)>                          \
 291     void name(_WX_VARARG_JOIN(N, _WX_VARARG_ARG))                           \
 292     {                                                                       \
 293         impl(_WX_VARARG_JOIN(N, _WX_VARARG_PASS));                          \
 294     }
 295
 296 // Macro to be used with _WX_VARARG_ITER in the implementation of
 297 // WX_DEFINE_VARARG_FUNC_NOP, i.e. empty stub for a disabled vararg function.
 298 // The rettype and impl arguments are ignored.
 299 #define _WX_VARARG_DEFINE_FUNC_NOP(N, rettype, name, impl)                  \
 300     template<_WX_VARARG_JOIN(N, _WX_VARARG_TEMPL)>                          \
 301     void name(_WX_VARARG_JOIN(N, _WX_VARARG_ARG_UNUSED)) {}
 302
 303
 304 #endif // _WX_STRVARARG_H_