// -*- C++ -*- // Copyright (C) 2005, 2006, 2007, 2009 Free Software Foundation, Inc. // // This file is part of the GNU ISO C++ Library. This library is free // software; you can redistribute it and/or modify it under the terms // of the GNU General Public License as published by the Free Software // Foundation; either version 3, 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 // General Public License for more details. // Under Section 7 of GPL version 3, you are granted additional // permissions described in the GCC Runtime Library Exception, version // 3.1, as published by the Free Software Foundation. // You should have received a copy of the GNU General Public License and // a copy of the GCC Runtime Library Exception along with this program; // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see // <http://www.gnu.org/licenses/>. /** @file ext/type_traits.h * This file is a GNU extension to the Standard C++ Library. */ #ifndef _EXT_TYPE_TRAITS #define _EXT_TYPE_TRAITS 1 #pragma GCC system_header #include <bits/c++config.h> #include <bits/cpp_type_traits.h> _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx) // Define a nested type if some predicate holds. template<bool, typename> struct __enable_if { }; template<typename _Tp> struct __enable_if<true, _Tp> { typedef _Tp __type; }; // Conditional expression for types. If true, first, if false, second. template<bool _Cond, typename _Iftrue, typename _Iffalse> struct __conditional_type { typedef _Iftrue __type; }; template<typename _Iftrue, typename _Iffalse> struct __conditional_type<false, _Iftrue, _Iffalse> { typedef _Iffalse __type; }; // Given an integral builtin type, return the corresponding unsigned type. template<typename _Tp> struct __add_unsigned { private: typedef __enable_if<std::__is_integer<_Tp>::__value, _Tp> __if_type; public: typedef typename __if_type::__type __type; }; template<> struct __add_unsigned<char> { typedef unsigned char __type; }; template<> struct __add_unsigned<signed char> { typedef unsigned char __type; }; template<> struct __add_unsigned<short> { typedef unsigned short __type; }; template<> struct __add_unsigned<int> { typedef unsigned int __type; }; template<> struct __add_unsigned<long> { typedef unsigned long __type; }; template<> struct __add_unsigned<long long> { typedef unsigned long long __type; }; // Declare but don't define. template<> struct __add_unsigned<bool>; template<> struct __add_unsigned<wchar_t>; // Given an integral builtin type, return the corresponding signed type. template<typename _Tp> struct __remove_unsigned { private: typedef __enable_if<std::__is_integer<_Tp>::__value, _Tp> __if_type; public: typedef typename __if_type::__type __type; }; template<> struct __remove_unsigned<char> { typedef signed char __type; }; template<> struct __remove_unsigned<unsigned char> { typedef signed char __type; }; template<> struct __remove_unsigned<unsigned short> { typedef short __type; }; template<> struct __remove_unsigned<unsigned int> { typedef int __type; }; template<> struct __remove_unsigned<unsigned long> { typedef long __type; }; template<> struct __remove_unsigned<unsigned long long> { typedef long long __type; }; // Declare but don't define. template<> struct __remove_unsigned<bool>; template<> struct __remove_unsigned<wchar_t>; // For use in string and vstring. template<typename _Type> inline bool __is_null_pointer(_Type* __ptr) { return __ptr == 0; } template<typename _Type> inline bool __is_null_pointer(_Type) { return false; } // For complex and cmath template<typename _Tp, bool = std::__is_integer<_Tp>::__value> struct __promote { typedef double __type; }; template<typename _Tp> struct __promote<_Tp, false> { typedef _Tp __type; }; template<typename _Tp, typename _Up> struct __promote_2 { private: typedef typename __promote<_Tp>::__type __type1; typedef typename __promote<_Up>::__type __type2; public: typedef __typeof__(__type1() + __type2()) __type; }; template<typename _Tp, typename _Up, typename _Vp> struct __promote_3 { private: typedef typename __promote<_Tp>::__type __type1; typedef typename __promote<_Up>::__type __type2; typedef typename __promote<_Vp>::__type __type3; public: typedef __typeof__(__type1() + __type2() + __type3()) __type; }; template<typename _Tp, typename _Up, typename _Vp, typename _Wp> struct __promote_4 { private: typedef typename __promote<_Tp>::__type __type1; typedef typename __promote<_Up>::__type __type2; typedef typename __promote<_Vp>::__type __type3; typedef typename __promote<_Wp>::__type __type4; public: typedef __typeof__(__type1() + __type2() + __type3() + __type4()) __type; }; _GLIBCXX_END_NAMESPACE #endif