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VS 中 __VA_ARGS__

VS 中 __VA_ARGS__

作者: 零度心脉 | 来源:发表于2019-07-19 09:55 被阅读0次

    //遍历不定参数,不定参数展开 <=9个
    //vs中这种方式定义宏过度也不能用

    define EXTAND_ARGS(args) args //VA_ARGS在vs中会被认为是一个实参,所以需要定义该宏过度

    define FOR_EACH_1(what,ParamType, ...) what(ParamType,1)

    define FOR_EACH_2(what,ParamType, ...) what(ParamType,2), EXTAND_ARGS(FOR_EACH_1(what, VA_ARGS))

    define FOR_EACH_3(what,ParamType, ...) what(ParamType,3), EXTAND_ARGS(FOR_EACH_2(what, VA_ARGS))

    define FOR_EACH_4(what,ParamType, ...) what(ParamType,4), EXTAND_ARGS(FOR_EACH_3(what, VA_ARGS))

    define FOR_EACH_5(what,ParamType, ...) what(ParamType,5), EXTAND_ARGS(FOR_EACH_4(what, VA_ARGS))

    define FOR_EACH_6(what,ParamType, ...) what(ParamType,6), EXTAND_ARGS(FOR_EACH_5(what, VA_ARGS))

    define FOR_EACH_7(what,ParamType, ...) what(ParamType,7), EXTAND_ARGS(FOR_EACH_6(what, VA_ARGS))

    define FOR_EACH_8(what,ParamType, ...) what(ParamType,8), EXTAND_ARGS(FOR_EACH_7(what, VA_ARGS))

    define FOR_EACH_9(what,ParamType, ...) what(ParamType,9), EXTAND_ARGS(FOR_EACH_8(what, VA_ARGS))

    define CONCATENATE(arg1, arg2) arg1##arg2

    //Parameters Table

    define PARAM_TABLE(ParamType,N) ParamType param##N

    define PARAM_TABLE_FOR_EACH_(N,...) EXTAND_ARGS(CONCATENATE(FOR_EACH_, N)(PARAM_TABLE,VA_ARGS))

    // Parameters Name

    define PARAM_NAME(ParamType,N) param##N

    define PARAM_NAME_FOR_EACH_(N,...) EXTAND_ARGS(CONCATENATE(FOR_EACH_, N)(PARAM_NAME,VA_ARGS))

    // 计算 VA_ARGS 参数个数,最大支持64个参数 //vs中无参数时会返回1

    define FL_ARG_COUNT(...) EXTAND_ARGS(FL_INTERNAL_ARG_COUNT_PRIVATE(0, VA_ARGS,\

    64, 63, 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 FL_INTERNAL_ARG_COUNT_PRIVATE(\

    _0,  _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, _64, N, ...) N
    

    define DeclarationAndDifinitionInterface(funcName,...) \

    virtual NPSDKError funcName(PARAM_TABLE_FOR_EACH_(EXTAND_ARGS(FL_ARG_COUNT(__VA_ARGS__)),__VA_ARGS__))      \
    

    {
    if (pImpl != NULL)
    {
    return pImpl->funcName(PARAM_NAME_FOR_EACH_(EXTAND_ARGS(FL_ARG_COUNT(VA_ARGS)),VA_ARGS));
    }
    return NPSDK_ERR_NOT_SUPPORT;
    }

    define CONCATSTR(...) fun(FL_ARG_COUNT(VA_ARGS),VA_ARGS)

    std::string fun(int d,const char* h,...)
    {
    va_list ap;
    va_start(ap,h);
    std::string sf =h;
    for (int i = 1; i < d; i++)
    {
    sf += va_arg(ap,const char*);
    }
    va_end(ap);
    return sf.data();
    }

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