diff options
Diffstat (limited to 'zen/string_traits.h')
| -rw-r--r-- | zen/string_traits.h | 84 |
1 files changed, 37 insertions, 47 deletions
diff --git a/zen/string_traits.h b/zen/string_traits.h index c06aa6e3..cfcf78bb 100644 --- a/zen/string_traits.h +++ b/zen/string_traits.h @@ -9,7 +9,6 @@ #define STRING_TRAITS_HEADER_813274321443234 #include "type_tools.h" -#include "type_traits.h" #include "assert_static.h" @@ -17,13 +16,13 @@ namespace zen { /* -IsStringLike<>::result: - IsStringLike<const wchar_t*>::result; //equals "true" - IsStringLike<const int*> ::result; //equals "false" +IsStringLike<>::value: + IsStringLike<const wchar_t*>::value; //equals "true" + IsStringLike<const int*> ::value; //equals "false" -GetCharType<>::Result: - GetCharType<std::wstring>::Result //equals wchar_t - GetCharType<wchar_t[5]> ::Result //equals wchar_t +GetCharType<>::Type: + GetCharType<std::wstring>::Type //equals wchar_t + GetCharType<wchar_t[5]> ::Type //equals wchar_t strBegin(): std::wstring str(L"dummy"); @@ -67,21 +66,6 @@ private: //---------------------- implementation ---------------------- namespace implementation { -ZEN_INIT_DETECT_MEMBER(c_str) //we don't know the exact declaration of the member attribute and it may be in a base class! -ZEN_INIT_DETECT_MEMBER(length) // - -template<typename T, bool isClassType> -struct HasStringMembers { enum { result = false }; }; - -template<typename T> -struct HasStringMembers<T, true> //Note: we can apply non-typed member-check on class types only! -{ - enum { result = HasMember_c_str <T>::result && - HasMember_length<T>::result - }; -}; - - template<class S, class Char> //test if result of S::c_str() can convert to const Char* class HasConversion { @@ -91,63 +75,69 @@ class HasConversion static Yes& hasConversion(const Char*); static No& hasConversion(...); - static S createInstance(); + static S& createInstance(); public: - enum { result = sizeof(hasConversion(createInstance().c_str())) == sizeof(Yes) }; + enum { value = sizeof(hasConversion(createInstance().c_str())) == sizeof(Yes) }; }; -template <class S, bool isStringClass> struct GetCharTypeImpl { typedef EmptyType Result; }; -template <class S> struct GetCharTypeImpl<S, true > +template <class S, bool isStringClass> struct GetCharTypeImpl : ResultType<NullType> {}; +template <class S> +struct GetCharTypeImpl<S, true> : + ResultType< + typename SelectIf<HasConversion<S, wchar_t>::value, wchar_t, + typename SelectIf<HasConversion<S, char >::value, char, NullType>::Type + >::Type> { - //typedef typename S::value_type Result; + //typedef typename S::value_type Type; /*DON'T use S::value_type: 1. support Glib::ustring: value_type is "unsigned int" but c_str() returns "const char*" 2. wxString, wxWidgets v2.9, has some questionable string design: wxString::c_str() returns a proxy (wxCStrData) which is implicitly convertible to *both* "const char*" and "const wchar_t*" while wxString::value_type is a wrapper around an unsigned int */ - typedef typename SelectIf<HasConversion<S, wchar_t>::result, wchar_t, - typename SelectIf<HasConversion<S, char>::result, char, EmptyType>::Result - >::Result Result; }; - -template <> struct GetCharTypeImpl<char, false> { typedef char Result; }; -template <> struct GetCharTypeImpl<wchar_t, false> { typedef wchar_t Result; }; +template <> struct GetCharTypeImpl<char, false> : ResultType<char > {}; +template <> struct GetCharTypeImpl<wchar_t, false> : ResultType<wchar_t> {}; ZEN_INIT_DETECT_MEMBER_TYPE(value_type); +ZEN_INIT_DETECT_MEMBER(c_str); //we don't know the exact declaration of the member attribute and it may be in a base class! +ZEN_INIT_DETECT_MEMBER(length); // template <class S> class StringTraits { - typedef typename RemoveRef <S >::Result NonRefType; - typedef typename RemoveConst <NonRefType >::Result NonConstType; - typedef typename RemoveArray <NonConstType>::Result NonArrayType; - typedef typename RemovePointer<NonArrayType>::Result NonPtrType; - typedef typename RemoveConst <NonPtrType >::Result UndecoratedType; //handle "const char* const" + typedef typename RemoveRef <S >::Type NonRefType; + typedef typename RemoveConst <NonRefType >::Type NonConstType; + typedef typename RemoveArray <NonConstType>::Type NonArrayType; + typedef typename RemovePointer<NonArrayType>::Type NonPtrType; + typedef typename RemoveConst <NonPtrType >::Type UndecoratedType; //handle "const char* const" public: enum { - isStringClass = HasStringMembers<NonConstType, HasMemberType_value_type<NonConstType>::result>::result + isStringClass = HasMemberType_value_type<NonConstType>::value && + HasMember_c_str <NonConstType>::value && + HasMember_length <NonConstType>::value }; - typedef typename GetCharTypeImpl<UndecoratedType, isStringClass>::Result CharType; + typedef typename GetCharTypeImpl<UndecoratedType, isStringClass>::Type CharType; enum { - isStringLike = IsSameType<CharType, char>::result || - IsSameType<CharType, wchar_t>::result + isStringLike = + IsSameType<CharType, char >::value || + IsSameType<CharType, wchar_t>::value }; }; } template <class T> -struct IsStringLike { enum { result = implementation::StringTraits<T>::isStringLike }; }; +struct IsStringLike : StaticBool<implementation::StringTraits<T>::isStringLike> {}; template <class T> -struct GetCharType { typedef typename implementation::StringTraits<T>::CharType Result; }; +struct GetCharType : ResultType<typename implementation::StringTraits<T>::CharType> {}; namespace implementation @@ -155,7 +145,7 @@ namespace implementation template <class C> inline size_t cStringLength(const C* str) //strlen() { - assert_static((IsSameType<C, char>::result || IsSameType<C, wchar_t>::result)); + assert_static((IsSameType<C, char>::value || IsSameType<C, wchar_t>::value)); size_t len = 0; while (*str++ != 0) ++len; @@ -165,7 +155,7 @@ size_t cStringLength(const C* str) //strlen() template <class S> inline -const typename GetCharType<S>::Result* strBegin(const S& str, typename EnableIf<implementation::StringTraits<S>::isStringClass>::Result* = NULL) //SFINAE: T must be a "string" +const typename GetCharType<S>::Type* strBegin(const S& str, typename EnableIf<implementation::StringTraits<S>::isStringClass>::Type* = nullptr) //SFINAE: T must be a "string" { return str.c_str(); } @@ -177,7 +167,7 @@ inline const wchar_t* strBegin(const wchar_t& ch) { return &ch; } template <class S> inline -size_t strLength(const S& str, typename EnableIf<implementation::StringTraits<S>::isStringClass>::Result* = NULL) //SFINAE: T must be a "string" +size_t strLength(const S& str, typename EnableIf<implementation::StringTraits<S>::isStringClass>::Type* = nullptr) //SFINAE: T must be a "string" { return str.length(); } |