c++编程中处理char和wchar_t的好工具

/*
 ttype.h
 sdragonx 2015-02-18 18:32:43
 这个几个模版函数是为了处理ansi或unicode，使字符串值或者字符串函数能够在模版中使用
 2018/7/26 23:20
 ttype<char, char, wchar_t>::type        //type is char
 ttype<wchar_t, char, wchar_t>::type    //type is wchar_t
 char* str = tvalue<char>("ansi", "wide");            //return "ansi"
 wchar_t* str = tvalue<wchar_t>("ansi", "wide");    //return "wide"
 template<typename T>
 size_t cslen(const T* str)//有了这个函数，模板编程会方便很多
 {
    return tvalue<TCHAR>(strlen, wcslen)("abc");
 }
 TCHAR* s = T_TEXT(TCHAR, "abc");    //if TCHAR is char, s is "abc"; else s is L"abc"
*/
#ifndef STL_TTYPE_H_20150218183243
#define STL_TTYPE_H_20150218183243

namespace cgl{

//
// ttype
//

template<typename _char_t, typename TA, typename TW>
struct ttype;

template<typename TA, typename TW>
struct ttype<char, TA, TW>
{
    typedef TA type;
};

template<typename TA, typename TW>
struct ttype<wchar_t, TA, TW>
{
    typedef TW type;
};

//
//tvalue
//

template<typename TA,typename TW>
inline typename ttype<char, TA, TW>::type tvalue(char*, TA a, TW w)
{
    return a;
}

template<typename TA,typename TW>
inline typename ttype<wchar_t, TA, TW>::type tvalue(wchar_t*, TA a, TW w)
{
    return w;
}

template<typename _char_t, typename TA,typename TW>
inline typename ttype<_char_t, TA, TW>::type tvalue(TA a, TW w)
{
    return tvalue<TA, TW>(static_cast<_char_t*>(), a, w);
}

#define T_TEXT(T, S) tvalue<T>(S, L##S)

}//end namespace cgl

#endif//STL_TTYPE_H_20150218183243