【Macro definition】——judging whether the value of the macro is a specific value

Function Description

Used to determine whether the value of the macro is a specific value

old way

#define CFG_MCU      10

#if (CFG_MCU == 10)
xxx
#endif

new method

#define _TU_CHECK_MCU(_m)   (CFG_MCU == _m)
#define TU_CHECK_MCU(...)   (TU_ARGS_APPLY(_TU_CHECK_MCU, ||, 1))

#if TU_CHECK_MCU(100)
xxx
#endif

accomplish

#define _GET_NTH_ARG( \
          _1, _2, _3, _4, _5, _6, _7, _8, _9,_10, \
         _11,_12,_13,_14,_15,_16,_17,_18,_19,_20, \
         _21,_22,_23,_24,_25,_26,_27,_28,_29,_30, \
         _31,_32,_33,_34,_35,_36,_37,_38,_39,_40, \
         _41,_42,_43,_44,_45,_46,_47,_48,_49,_50, \
         _51,_52,_53,_54,_55,_56,_57,_58,_59,_60, \
         _61,_62,_63,N,...) N
#define _RSEQ_N() \
         62,61,60,                      \
         59,58,57,56,55,54,53,52,51,50, \
         49,48,47,46,45,44,43,42,41,40, \
         39,38,37,36,35,34,33,32,31,30, \
         29,28,27,26,25,24,23,22,21,20, \
         19,18,17,16,15,14,13,12,11,10, \
         9,8,7,6,5,4,3,2,1,0

#define _TU_NARG(...)      _GET_NTH_ARG(__VA_ARGS__)

#define TU_ARGS_NUM(...)   _TU_NARG(_0, __VA_ARGS__, _RSEQ_N()) /* 该宏用于获取宏有几个参数 */

// Apply an macro X to each of the arguments with an separated of choice
#define TU_ARGS_APPLY(_X, _s, ...)   TU_XSTRCAT(_TU_ARGS_APPLY_, TU_ARGS_NUM(__VA_ARGS__))(_X, _s, __VA_ARGS__)

#define _TU_ARGS_APPLY_1(_X, _s, _a1)                                    _X(_a1)
#define _TU_ARGS_APPLY_2(_X, _s, _a1, _a2)                               _X(_a1) _s _X(_a2)
#define _TU_ARGS_APPLY_3(_X, _s, _a1, _a2, _a3)                          _X(_a1) _s _TU_ARGS_APPLY_2(_X, _s, _a2, _a3)
#define _TU_ARGS_APPLY_4(_X, _s, _a1, _a2, _a3, _a4)                     _X(_a1) _s _TU_ARGS_APPLY_3(_X, _s, _a2, _a3, _a4)
#define _TU_ARGS_APPLY_5(_X, _s, _a1, _a2, _a3, _a4, _a5)                _X(_a1) _s _TU_ARGS_APPLY_4(_X, _s, _a2, _a3, _a4, _a5)
#define _TU_ARGS_APPLY_6(_X, _s, _a1, _a2, _a3, _a4, _a5, _a6)           _X(_a1) _s _TU_ARGS_APPLY_5(_X, _s, _a2, _a3, _a4, _a5, _a6)
#define _TU_ARGS_APPLY_7(_X, _s, _a1, _a2, _a3, _a4, _a5, _a6, _a7)      _X(_a1) _s _TU_ARGS_APPLY_6(_X, _s, _a2, _a3, _a4, _a5, _a6, _a7)
#define _TU_ARGS_APPLY_8(_X, _s, _a1, _a2, _a3, _a4, _a5, _a6, _a7, _a8) _X(_a1) _s _TU_ARGS_APPLY_7(_X, _s, _a2, _a3, _a4, _a5, _a6, _a7, _a8)


// Helper to check if configured MCU is one of listed
// Apply _TU_CHECK_MCU with || as separator to list of input
#define _TU_CHECK_MCU(_m)   (CFG_MCU == _m)
#define TU_CHECK_MCU(...)   (TU_ARGS_APPLY(_TU_CHECK_MCU, ||, OPT_MCU_NRF5X))

analyze

• TU_ARGS_APPLYIt is used to choose which one to use TU_ARGS_APPLYx, where TU_XSTRCAT(_TU_ARGS_APPLY_, TU_ARGS_NUM(__VA_ARGS__))is to connect with _TU_ARGS_APPLY_and after the connection is etc. 宏参数个数 1 2 3_TU_ARGS_APPLY_1 _TU_ARGS_APPLY_2
• After the macro connection is _TU_ARGS_APPLY_1(_X, _s, __VA_ARGS__)the macro, the macro expansion is _TU_CHECK_MCU(OPT_MCU_NRF5X), and the macro expansion isCFG_MCU == OPT_MCU_NRF5X
• If there are _TU_ARGS_APPLY_2(_X, _s, a1, a2)macros with multiple parameters that are or more parameters, the macro expansion is _TU_CHECK_MCU(a1) -s _TU_CHECK_MCU(a2)that _TU_CHECK_MCU(a1) || _TU_CHECK_MCU(a2)the expansion isCFG_MCU == a1 || CFG_MCU == a2