Move Source/WTF/wtf to Source/wtf

Source/WTF/wtf/TypeTraits.h

- /*
- * Copyright (C) 2006, 2007, 2008 Apple Inc. All rights reserved.
- * Copyright (C) 2009, 2010 Google Inc. All rights reserved.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Library General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public License
- * along with this library; see the file COPYING.LIB.  If not, write to
- * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
- * Boston, MA 02110-1301, USA.
- *
- */
-
-#ifndef TypeTraits_h
-#define TypeTraits_h
-
-#include <wtf/Platform.h>
-
-#if (defined(__GLIBCXX__) && (__GLIBCXX__ >= 20070724) && defined(__GXX_EXPERIMENTAL_CXX0X__)) || (defined(_MSC_VER) && (_MSC_VER >= 1600))
-#include <type_traits>
-#if defined(__GLIBCXX__) && (__GLIBCXX__ >= 20070724) && defined(__GXX_EXPERIMENTAL_CXX0X__)
-#include <tr1/memory>
-#endif
-#endif
-
-namespace WTF {
-
-    // The following are provided in this file:
-    //
-    //   Conditional<Predicate, If, Then>::Type
-    //
-    //   IsInteger<T>::value
-    //   IsPod<T>::value, see the definition for a note about its limitations
-    //   IsConvertibleToInteger<T>::value
-    //
-    //   IsArray<T>::value
-    //
-    //   IsSameType<T, U>::value
-    //
-    //   RemovePointer<T>::Type
-    //   RemoveReference<T>::Type
-    //   RemoveConst<T>::Type
-    //   RemoveVolatile<T>::Type
-    //   RemoveConstVolatile<T>::Type
-    //   RemoveExtent<T>::Type
-    //
-    //   DecayArray<T>::Type
-    //
-    //   COMPILE_ASSERT's in TypeTraits.cpp illustrate their usage and what they do.
-
-    template <bool Predicate, class If, class Then> struct Conditional  { typedef If Type; };
-    template <class If, class Then> struct Conditional<false, If, Then> { typedef Then Type; };
-
-    template<typename T> struct IsInteger           { static const bool value = false; };
-    template<> struct IsInteger<bool>               { static const bool value = true; };
-    template<> struct IsInteger<char>               { static const bool value = true; };
-    template<> struct IsInteger<signed char>        { static const bool value = true; };
-    template<> struct IsInteger<unsigned char>      { static const bool value = true; };
-    template<> struct IsInteger<short>              { static const bool value = true; };
-    template<> struct IsInteger<unsigned short>     { static const bool value = true; };
-    template<> struct IsInteger<int>                { static const bool value = true; };
-    template<> struct IsInteger<unsigned int>       { static const bool value = true; };
-    template<> struct IsInteger<long>               { static const bool value = true; };
-    template<> struct IsInteger<unsigned long>      { static const bool value = true; };
-    template<> struct IsInteger<long long>          { static const bool value = true; };
-    template<> struct IsInteger<unsigned long long> { static const bool value = true; };
-#if !COMPILER(MSVC) || defined(_NATIVE_WCHAR_T_DEFINED)
-    template<> struct IsInteger<wchar_t>            { static const bool value = true; };
-#endif
-
-    template<typename T> struct IsFloatingPoint     { static const bool value = false; };
-    template<> struct IsFloatingPoint<float>        { static const bool value = true; };
-    template<> struct IsFloatingPoint<double>       { static const bool value = true; };
-    template<> struct IsFloatingPoint<long double>  { static const bool value = true; };
-
-    template<typename T> struct IsArithmetic     { static const bool value = IsInteger<T>::value || IsFloatingPoint<T>::value; };
-
-    // IsPod is misnamed as it doesn't cover all plain old data (pod) types.
-    // Specifically, it doesn't allow for enums or for structs.
-    template <typename T> struct IsPod           { static const bool value = IsArithmetic<T>::value; };
-    template <typename P> struct IsPod<P*>       { static const bool value = true; };
-
-    template<typename T> class IsConvertibleToInteger {
-        // Avoid "possible loss of data" warning when using Microsoft's C++ compiler
-        // by not converting int's to doubles.
-        template<bool performCheck, typename U> class IsConvertibleToDouble;
-        template<typename U> class IsConvertibleToDouble<false, U> {
-        public:
-            static const bool value = false;
-        };
-
-        template<typename U> class IsConvertibleToDouble<true, U> {
-            typedef char YesType;
-            struct NoType {
-                char padding[8];
-            };
-
-            static YesType floatCheck(long double);
-            static NoType floatCheck(...);
-            static T& t;
-        public:
-            static const bool value = sizeof(floatCheck(t)) == sizeof(YesType);
-        };
-
-    public:
-        static const bool value = IsInteger<T>::value || IsConvertibleToDouble<!IsInteger<T>::value, T>::value;
-    };
-
-
-    template <class T> struct IsArray {
-        static const bool value = false;
-    };
-
-    template <class T> struct IsArray<T[]> {
-        static const bool value = true;
-    };
-
-    template <class T, size_t N> struct IsArray<T[N]> {
-        static const bool value = true;
-    };
-
-
-    template <typename T, typename U> struct IsSameType {
-        static const bool value = false;
-    };
-
-    template <typename T> struct IsSameType<T, T> {
-        static const bool value = true;
-    };
-
-    template <typename T, typename U> class IsSubclass {
-        typedef char YesType;
-        struct NoType {
-            char padding[8];
-        };
-
-        static YesType subclassCheck(U*);
-        static NoType subclassCheck(...);
-        static T* t;
-    public:
-        static const bool value = sizeof(subclassCheck(t)) == sizeof(YesType);
-    };
-
-    template <typename T, template<class V> class U> class IsSubclassOfTemplate {
-        typedef char YesType;
-        struct NoType {
-            char padding[8];
-        };
-
-        template<typename W> static YesType subclassCheck(U<W>*);
-        static NoType subclassCheck(...);
-        static T* t;
-    public:
-        static const bool value = sizeof(subclassCheck(t)) == sizeof(YesType);
-    };
-
-    template <typename T, template <class V> class OuterTemplate> struct RemoveTemplate {
-        typedef T Type;
-    };
-
-    template <typename T, template <class V> class OuterTemplate> struct RemoveTemplate<OuterTemplate<T>, OuterTemplate> {
-        typedef T Type;
-    };
-
-    template <typename T> struct RemoveConst {
-        typedef T Type;
-    };
-
-    template <typename T> struct RemoveConst<const T> {
-        typedef T Type;
-    };
-
-    template <typename T> struct RemoveVolatile {
-        typedef T Type;
-    };
-
-    template <typename T> struct RemoveVolatile<volatile T> {
-        typedef T Type;
-    };
-
-    template <typename T> struct RemoveConstVolatile {
-        typedef typename RemoveVolatile<typename RemoveConst<T>::Type>::Type Type;
-    };
-
-    template <typename T> struct RemovePointer {
-        typedef T Type;
-    };
-
-    template <typename T> struct RemovePointer<T*> {
-        typedef T Type;
-    };
-
-    template <typename T> struct RemoveReference {
-        typedef T Type;
-    };
-
-    template <typename T> struct RemoveReference<T&> {
-        typedef T Type;
-    };
-
-    template <typename T> struct RemoveExtent {
-        typedef T Type;
-    };
-
-    template <typename T> struct RemoveExtent<T[]> {
-        typedef T Type;
-    };
-
-    template <typename T, size_t N> struct RemoveExtent<T[N]> {
-        typedef T Type;
-    };
-
-    template <class T> struct DecayArray {
-        typedef typename RemoveReference<T>::Type U;
-    public:
-        typedef typename Conditional<
-            IsArray<U>::value,
-            typename RemoveExtent<U>::Type*,
-            typename RemoveConstVolatile<U>::Type
-        >::Type Type;
-    };
-
-#if COMPILER(CLANG) || GCC_VERSION_AT_LEAST(4, 6, 0) || (defined(_MSC_VER) && (_MSC_VER >= 1400) && (_MSC_VER < 1600) && !defined(__INTEL_COMPILER))
-    // VC8 (VS2005) and later has __has_trivial_constructor and __has_trivial_destructor,
-    // but the implementation returns false for built-in types. We add the extra IsPod condition to 
-    // work around this.
-    template <typename T> struct HasTrivialConstructor {
-        static const bool value = __has_trivial_constructor(T) || IsPod<RemoveConstVolatile<T> >::value;
-    };
-    template <typename T> struct HasTrivialDestructor {
-        static const bool value = __has_trivial_destructor(T) || IsPod<RemoveConstVolatile<T> >::value;
-    };
-#elif (defined(__GLIBCXX__) && (__GLIBCXX__ >= 20070724) && defined(__GXX_EXPERIMENTAL_CXX0X__)) || (defined(_MSC_VER) && (_MSC_VER >= 1600))
-    // GCC's libstdc++ 20070724 and later supports C++ TR1 type_traits in the std namespace.
-    // VC10 (VS2010) and later support C++ TR1 type_traits in the std::tr1 namespace.
-    template<typename T> struct HasTrivialConstructor : public std::tr1::has_trivial_constructor<T> { };
-    template<typename T> struct HasTrivialDestructor : public std::tr1::has_trivial_destructor<T> { };
-#else
-    // For compilers that don't support detection of trivial constructors and destructors in classes, 
-    // we use a template that returns true for any POD type that IsPod can detect (see IsPod caveats above), 
-    // but false for all other types (which includes all classes). This will give false negatives, which can hurt 
-    // performance, but avoids false positives, which would result in incorrect behavior.
-    template <typename T> struct HasTrivialConstructor {
-        static const bool value = IsPod<RemoveConstVolatile<T> >::value;
-    };
-    template <typename T> struct HasTrivialDestructor {
-        static const bool value = IsPod<RemoveConstVolatile<T> >::value;
-    };
-#endif
-
-} // namespace WTF
-
-#endif // TypeTraits_h