[6452] | 1 | /* |
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| 2 | * ORXONOX - the hottest 3D action shooter ever to exist |
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| 3 | * > www.orxonox.net < |
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| 4 | * |
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| 5 | * |
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| 6 | * License notice: |
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| 7 | * |
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| 8 | * This program is free software; you can redistribute it and/or |
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| 9 | * modify it under the terms of the GNU General Public License |
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| 10 | * as published by the Free Software Foundation; either version 2 |
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| 11 | * of the License, or (at your option) any later version. |
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| 12 | * |
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| 13 | * This program is distributed in the hope that it will be useful, |
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| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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| 16 | * GNU General Public License for more details. |
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| 17 | * |
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| 18 | * You should have received a copy of the GNU General Public License |
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| 19 | * along with this program; if not, write to the Free Software |
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| 20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. |
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| 21 | * |
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| 22 | * Author: |
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| 23 | * Fabian 'x3n' Landau |
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| 24 | * Co-authors: |
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| 25 | * ... |
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| 26 | * |
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| 27 | */ |
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| 28 | |
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| 29 | /** |
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| 30 | @file |
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[7401] | 31 | @ingroup Util |
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[6452] | 32 | @brief Declaration of the ORXONOX_VA_NARGS macro which returns the number of arguments passed to a variadic macro. |
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[7401] | 33 | |
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| 34 | With this utility you can overload a macro for different numbers of arguments |
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| 35 | (of course overloading is not possible for different types, as macros are not |
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| 36 | type aware, but for different numbers of arguments is still very powerful). |
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| 37 | |
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[9550] | 38 | Important: The macro can not be overloaded for 0 arguments: ORXONOX_VA_NARGS() returns 1! |
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| 39 | |
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[7401] | 40 | Example: A macro to call functions |
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| 41 | @code |
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| 42 | myfunction(); // A static function |
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| 43 | MyClass::myStaticFunction(); // A static class function |
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| 44 | MyClass::myFunction(); // A member function |
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| 45 | |
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| 46 | #define CallFunction(...) \ // Define a variadic macro that passes the arguments to the overloaded implementations |
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| 47 | BOOST_PP_EXPAND(BOOST_PP_CAT(CallFunction, ORXONOX_VA_NARGS(__VA_ARGS__))(__VA_ARGS__)) |
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| 48 | |
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| 49 | #define CallFunction1(function) \ // Overloaded macro for 1 argument |
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| 50 | function() // Calls the static function |
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| 51 | |
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| 52 | #define CallFunction2(class, function) \ // Overloaded macro for 2 arguments |
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| 53 | class::function() // Calls the static class function |
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| 54 | |
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| 55 | #define CallFunction3(class, function, object) \ // Overloaded macro for 3 arguments |
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| 56 | object->class::function() // Calls the function on the object |
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| 57 | |
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| 58 | |
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| 59 | CallFunction(myFunction); // Call the macro with 1 argument |
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| 60 | CallFunction(MyClass, myStaticFunction); // Call the macro with 2 arguments |
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| 61 | CallFunction(MyClass, myFunction, new MyClass()); // Call the macro with 3 arguments |
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| 62 | @endcode |
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| 63 | |
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| 64 | Note that the first (variadic) macro concatenates the name "CallFunction" with |
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| 65 | the number of arguments ("1" - "N"). Then all arguments are passed to the right macro. |
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[6452] | 66 | */ |
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| 67 | |
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[9550] | 68 | #include <boost/preprocessor/cat.hpp> |
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[6454] | 69 | #include <boost/preprocessor/facilities/expand.hpp> |
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| 70 | |
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[6452] | 71 | /** |
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| 72 | @brief Returns the number of arguments passed to a variadic macro. Important: The number of arguments must be greater than zero (ORXONOX_VA_NARGS() returns 1). |
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| 73 | */ |
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| 74 | #define ORXONOX_VA_NARGS(...) \ |
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| 75 | ORXONOX_VA_NARGS_CONCAT(__VA_ARGS__, ORXONOX_VA_NARGS_NUMBERS) |
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| 76 | |
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| 77 | |
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| 78 | // some helper macros // |
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| 79 | |
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| 80 | #define ORXONOX_VA_NARGS_CONCAT(...) \ |
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[6454] | 81 | BOOST_PP_EXPAND(ORXONOX_VA_NARGS_INTERN(__VA_ARGS__)) |
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[6452] | 82 | |
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| 83 | #define ORXONOX_VA_NARGS_INTERN( \ |
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| 84 | arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, \ |
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| 85 | arg11, arg12, arg13, arg14, arg15, arg16, arg17, arg18, arg19, arg20, \ |
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| 86 | arg21, arg22, arg23, arg24, arg25, arg26, arg27, arg28, arg29, arg30, \ |
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| 87 | arg31, arg32, arg33, arg34, arg35, arg36, arg37, arg38, arg39, arg40, \ |
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| 88 | arg41, arg42, arg43, arg44, arg45, arg46, arg47, arg48, arg49, arg50, \ |
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| 89 | arg51, arg52, arg53, arg54, arg55, arg56, arg57, arg58, arg59, arg60, \ |
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| 90 | arg61, arg62, arg63, argn, ...) argn |
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| 91 | |
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| 92 | #define ORXONOX_VA_NARGS_NUMBERS \ |
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| 93 | 63, 62, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, \ |
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| 94 | 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, \ |
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| 95 | 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, \ |
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| 96 | 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 |
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