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Diffstat (limited to 'src/libstrongswan/utils/utils.h')
| -rw-r--r-- | src/libstrongswan/utils/utils.h | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/src/libstrongswan/utils/utils.h b/src/libstrongswan/utils/utils.h index 3c1a203a1..66d91a595 100644 --- a/src/libstrongswan/utils/utils.h +++ b/src/libstrongswan/utils/utils.h @@ -278,6 +278,32 @@ static inline void *memset_noop(void *s, int c, size_t n) static ret _cb_##name(param1, ##__VA_ARGS__) /** + * This macro allows counting the number of arguments passed to a macro. + * Combined with the VA_ARGS_DISPATCH() macro this can be used to implement + * macro overloading based on the number of arguments. + * 0 to 10 arguments are currently supported. + */ +#define VA_ARGS_NUM(...) _VA_ARGS_NUM(0,##__VA_ARGS__,10,9,8,7,6,5,4,3,2,1,0) +#define _VA_ARGS_NUM(_0,_1,_2,_3,_4,_5,_6,_7,_8,_9,_10,NUM,...) NUM + +/** + * This macro can be used to dispatch a macro call based on the number of given + * arguments, for instance: + * + * @code + * #define MY_MACRO(...) VA_ARGS_DISPATCH(MY_MACRO, __VA_ARGS__)(__VA_ARGS__) + * #define MY_MACRO1(arg) one_arg(arg) + * #define MY_MACRO2(arg1,arg2) two_args(arg1,arg2) + * @endcode + * + * MY_MACRO() can now be called with either one or two arguments, which will + * resolve to one_arg(arg) or two_args(arg1,arg2), respectively. + */ +#define VA_ARGS_DISPATCH(func, ...) _VA_ARGS_DISPATCH(func, VA_ARGS_NUM(__VA_ARGS__)) +#define _VA_ARGS_DISPATCH(func, num) __VA_ARGS_DISPATCH(func, num) +#define __VA_ARGS_DISPATCH(func, num) func ## num + +/** * Architecture independent bitfield definition helpers (at least with GCC). * * Defines a bitfield with a type t and a fixed size of bitfield members, e.g.: |