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- /*!
- * \file integralconstant.h
- * \brief Template meta-programming integral constant
- *
- * Copyright (C) 2018-2019 Christos Choutouridis
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Lesser General Public License as
- * published by the Free Software Foundation, either version 3
- * of the License, or (at your option) any later version.
- *
- * This program 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 Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
- #ifndef __utl_meta_integralconstant_h__
- #define __utl_meta_integralconstant_h__
-
- #include <utl/core/impl.h>
-
-
- /*!
- * \ingroup meta
- * \defgroup integral
- * integral constant support header
- */
- //! @{
-
- namespace utl {
- namespace meta {
-
- /*!
- * Empty type
- * utl::meta's nil type is not pure nil. It's a recursive "de-referencable nil.
- * Each time someone applies ::type to it, he gets back nil_. This way we can prevent
- * a lot of compilation errors in a wrong meta:: handling.
- */
- struct nil_ {
- using type = nil_;
- };
-
- //! Type alias for \p _Tp::type. Used to evaluate/extract return type of metafunctions
- template <typename _Tp>
- using eval = typename _Tp::type;
-
- //! integral_
- //! Integral Constant is a holder class for a compile-time value of an integral type.
- //! Every Integral Constant is also a null-ary Metafunction, returning itself.
- //! An integral constant object is implicitly convertible to the corresponding
- //! run-time value of the wrapped integral type
- //! @{
- template <typename _Tp, _Tp _v>
- struct integral_ {
- using value_type = _Tp;
- using type = integral_<_Tp, _v>;
-
- constexpr operator value_type() const noexcept {
- return value;
- }
- constexpr value_type operator()() const noexcept {
- return value;
- }
- static constexpr _Tp value = _v;
- };
-
- template<typename _Tp, _Tp _v>
- constexpr _Tp integral_<_Tp, _v>::value;
- //! @}
-
- //! Wrappers for basic types
- //! @{
-
- //! bool_ type: integral constant wrapper for bool
- template<bool _v>
- using bool_ = integral_<bool, _v>;
-
- using true_ = bool_<true>; //!< The type used as a compile-time boolean with true value.
- using false_ = bool_<false>; //!< The type used as a compile-time boolean with false value.
-
- //! int8_ type: integral constant wrapper for \c int8_t
- template<int8_t _v>
- using int8_ = integral_<int8_t, _v>;
- //! uint8_ type: integral constant wrapper for \c uint8_t
- template<uint8_t _v>
- using uint8_ = integral_<uint8_t, _v>;
-
- //! int16_ type: integral constant wrapper for \c int16_t
- template<int16_t _v>
- using int16_ = integral_<int16_t, _v>;
- //! uint16_ type: integral constant wrapper for \c uint16_t
- template<uint16_t _v>
- using uint16_ = integral_<uint16_t, _v>;
-
- //! int32_ type: integral constant wrapper for \c int32_t
- template<int32_t _v>
- using int32_ = integral_<int32_t, _v>;
- //! uint32_ type: integral constant wrapper for \c uint32_t
- template<uint32_t _v>
- using uint32_ = integral_<uint32_t, _v>;
-
- //! char_ type: integral constant wrapper for \c char
- template<char _v>
- using char_ = integral_<char, _v>;
-
- //! int_ type: integral constant wrapper for \c int
- template<int _v>
- using int_ = integral_<int, _v>;
-
- //! long_ type: integral constant wrapper for \c long
- template<long _v>
- using long_ = integral_<long, _v>;
-
- //! index_ type: integral constant wrapper for \c index_t a.k.a std::size_t
- template<index_t _v>
- using index_ = integral_<index_t, _v>;
-
- //! size_ type: integral constant wrapper for \c size_t a.k.a std::size_t
- template<size_t _v>
- using size_ = integral_<size_t, _v>;
-
- //! Computes the size of the type \p _Tp.
- //! Complexity \f$ O(1) \f$.
- template <typename _Tp>
- using sizeof_ = size_<sizeof(_Tp)>;
-
- //! Computes the alignment required for any instance of the type \p _Tp.
- //! Complexity \f$ O(1) \f$.
- template <typename _Tp>
- using alignof_ = size_<alignof(_Tp)>;
- //! @}
-
- //! The last position we can express for indexing
- using Npos = size_<index_t(-1)>;
-
- }}
- //!@}
-
- #endif /* __utl_meta_integralconstant_h__ */
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