Danny Robson
f6056153e3
This places, at long last, the core library code into the same namespace as the extended library code.
455 lines
14 KiB
C++
455 lines
14 KiB
C++
/*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*
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* Copyright 2012-2017 Danny Robson <danny@nerdcruft.net>
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*/
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#ifndef CRUFT_UTIL_TYPES_TRAITS_HPP
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#define CRUFT_UTIL_TYPES_TRAITS_HPP
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#include <memory>
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#include <type_traits>
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///////////////////////////////////////////////////////////////////////////////
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/// applies a series of type-modifiers to a provided type.
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///
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/// modifiers are applied in the order they are provided.
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///
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/// use without any modifiers results in the identity modifier.
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namespace cruft::types {
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//-------------------------------------------------------------------------
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template <typename TypeT, template <typename> class ...ModifierT>
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struct compose;
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//-------------------------------------------------------------------------
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template <typename TypeT>
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struct compose<TypeT> { using type = TypeT; };
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//-------------------------------------------------------------------------
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template <
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typename TypeT,
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template <typename> class HeadT,
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template <typename> class ...TailT
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>
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struct compose<TypeT, HeadT, TailT...> : public compose<
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typename HeadT<TypeT>::type,
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TailT...
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> { };
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//-------------------------------------------------------------------------
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template <typename T, template <typename> class ...Args>
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using chain_t = typename compose<T, Args...>::type;
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}
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namespace cruft::types {
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///////////////////////////////////////////////////////////////////////////
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/// CXX20: An early implementation of std::identity_t and related
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/// structures; useful for disabling template argument deduction, and
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/// higher order template functions.
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template <typename T>
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struct identity { using type = T; };
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//-------------------------------------------------------------------------
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template <typename T>
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using identity_t = typename identity<T>::type;
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}
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///////////////////////////////////////////////////////////////////////////////
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template <typename T> struct is_dereferencable : std::false_type { };
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template <typename T> struct is_dereferencable<T*> : std::true_type { };
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template <typename T> struct is_dereferencable<std::unique_ptr<T>> : std::true_type { };
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template <typename T> struct is_dereferencable<std::shared_ptr<T>> : std::true_type { };
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template <typename T> struct is_dereferencable<std::weak_ptr<T>> : std::true_type { };
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///////////////////////////////////////////////////////////////////////////////
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template <typename T> struct dereferenced_type {
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typedef typename std::enable_if<
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std::is_pointer<T>::value,
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std::remove_pointer<T>
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>::type type;
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};
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//-----------------------------------------------------------------------------
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template <typename T> struct dereferenced_type<std::unique_ptr<T>> { typedef T type; };
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template <typename T> struct dereferenced_type<std::shared_ptr<T>> { typedef T type; };
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template <typename T> struct dereferenced_type<std::weak_ptr<T>> { typedef T type; };
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///////////////////////////////////////////////////////////////////////////////
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/// find the unsigned version of a type if one exists
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template <typename T>
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struct try_unsigned
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{
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typedef typename std::make_unsigned<T>::type type;
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};
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//-----------------------------------------------------------------------------
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template <> struct try_unsigned<double> { typedef double type; };
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template <> struct try_unsigned<float > { typedef float type; };
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///////////////////////////////////////////////////////////////////////////////
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/// find the signed version of a type if one exists
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template <typename T>
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struct try_signed
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{
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typedef typename std::make_signed<T>::type type;
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};
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//-----------------------------------------------------------------------------
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template <> struct try_signed<double> { typedef double type; };
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template <> struct try_signed<float > { typedef float type; };
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///////////////////////////////////////////////////////////////////////////////
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/// checks if a type can be converted in all cases without modification
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template <typename T, typename U> struct is_lossless_cast : std::enable_if<
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std::is_integral<T>::value &&
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std::is_integral<U>::value &&
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std::is_signed<T>::value == std::is_signed<U>::value &&
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sizeof (T) <= sizeof (U),
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std::true_type
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>::value { };
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///////////////////////////////////////////////////////////////////////////////
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template <typename T> struct remove_restrict { using type = T; };
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template <typename T> struct remove_restrict<T *restrict> { using type = T*; };
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template <typename T>
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using remove_restrict_t = typename remove_restrict<T>::type;
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///////////////////////////////////////////////////////////////////////////////
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/// removes the noexcept type specifier from invokable types
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namespace detail {
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template <typename T>
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struct remove_noexcept
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{ using type = T; };
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//-------------------------------------------------------------------------
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template <typename ResultT, typename ...Args>
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struct remove_noexcept<ResultT(&)(Args...) noexcept> {
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using type = ResultT(&)(Args...);
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};
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//-------------------------------------------------------------------------
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template <typename ResultT, typename ...Args>
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struct remove_noexcept<ResultT(*const)(Args...) noexcept> {
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using type = ResultT(*const)(Args...);
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};
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//-------------------------------------------------------------------------
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template <typename ResultT, typename ...Args>
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struct remove_noexcept<ResultT(*)(Args...) noexcept> {
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using type = ResultT(*)(Args...);
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};
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//-------------------------------------------------------------------------
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template <typename ClassT, typename ResultT, typename ...Args>
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struct remove_noexcept<ResultT(ClassT::*)(Args...) noexcept> {
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using type = ResultT(ClassT::*)(Args...);
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};
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//-------------------------------------------------------------------------
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template <typename ClassT, typename ResultT, typename ...Args>
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struct remove_noexcept<ResultT(ClassT::*)(Args...) const noexcept> {
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using type = ResultT(ClassT::*)(Args...) const;
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};
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};
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//-----------------------------------------------------------------------------
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template <typename T>
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struct remove_noexcept : public detail::remove_noexcept<T> { };
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//-----------------------------------------------------------------------------
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template <typename T>
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using remove_noexcept_t = typename remove_noexcept<T>::type;
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///////////////////////////////////////////////////////////////////////////////
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/// removes any `const' qualifier from the supplied member function
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template <typename FuncT>
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struct remove_member_const {
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using type = FuncT;
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};
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//-----------------------------------------------------------------------------
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template <typename ClassT, typename ReturnT, typename ...Args>
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struct remove_member_const<ReturnT(ClassT::*const)(Args...) const> {
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using type = ReturnT(ClassT::*const)(Args...);
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};
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//-----------------------------------------------------------------------------
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template <typename ClassT, typename ReturnT, typename ...Args>
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struct remove_member_const<ReturnT(ClassT::*)(Args...) const> {
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using type = ReturnT(ClassT::*)(Args...);
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};
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///////////////////////////////////////////////////////////////////////////////
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/// type traits class for querying invokable type return values and argument
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/// types.
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///
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/// if the type is invokable the alias `return_type' will be defined for the
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/// return type, and the alias tuple `argument_types' will be defined for the
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/// arguments;
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namespace detail {
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template <typename T>
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struct func_traits { };
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//-------------------------------------------------------------------------
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template <typename ClassT, typename ResultT, typename ...Args>
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struct func_traits<ResultT(ClassT::*)(Args...)> {
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using return_type = ResultT;
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using argument_types = std::tuple<Args...>;
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};
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//-------------------------------------------------------------------------
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template <typename ResultT, typename ...Args>
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struct func_traits<ResultT(*)(Args...)> {
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using return_type = ResultT;
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using argument_types = std::tuple<Args...>;
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};
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//-------------------------------------------------------------------------
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template <typename ResultT, typename ...Args>
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struct func_traits<ResultT(&)(Args...)> {
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using return_type = ResultT;
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using argument_types = std::tuple<Args...>;
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};
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};
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//-----------------------------------------------------------------------------
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template <typename T>
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struct func_traits : public ::detail::func_traits<
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// we apply as many transforms as possible before palming it off to the
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// detail class so that we don't have to write as many distinct cases.
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::cruft::types::chain_t<T,
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std::remove_cv,
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std::decay,
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remove_member_const,
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remove_noexcept
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>
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> {
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// we may as well record the underlying type here. it might prove useful
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// to someone.
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using type = T;
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};
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///////////////////////////////////////////////////////////////////////////////
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template <typename FunctionT>
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struct function_argument_count : public std::integral_constant<
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size_t,
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std::tuple_size_v<
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typename func_traits<FunctionT>::argument_types
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>
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> { };
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//-----------------------------------------------------------------------------
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template <typename FunctionT>
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constexpr auto function_argument_count_v = function_argument_count<FunctionT>::value;
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///////////////////////////////////////////////////////////////////////////////
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template <std::size_t N, typename FuncT>
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struct nth_argument : std::tuple_element<
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N,
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typename func_traits<FuncT>::argument_types
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> { };
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template <std::size_t N, typename FuncT>
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using nth_argument_t = typename nth_argument<N, FuncT>::type;
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///////////////////////////////////////////////////////////////////////////////
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template <typename T, typename = std::void_t<>>
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struct is_container : public std::false_type {};
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template <typename T>
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struct is_container<
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T,
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std::void_t<
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typename T::value_type,
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typename T::reference,
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typename T::const_reference,
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typename T::iterator,
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typename T::const_iterator,
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typename T::difference_type,
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typename T::size_type
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>
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> : public std::true_type {};
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template <size_t N, typename ValueT>
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struct is_container<std::array<ValueT,N>> : public std::true_type {};
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template <typename T>
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constexpr auto is_container_v = is_container<T>::value;
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///////////////////////////////////////////////////////////////////////////////
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#include <string>
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#include <array>
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#include <vector>
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template <typename T>
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struct is_contiguous : public std::false_type {};
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template <typename CharT, typename Traits, typename Allocator>
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struct is_contiguous<std::basic_string<CharT, Traits, Allocator>> : public std::true_type {};
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template <typename T, std::size_t N>
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struct is_contiguous<std::array<T,N>>: public std::true_type {};
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template <typename T, typename Allocator>
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struct is_contiguous<std::vector<T,Allocator>>: public std::true_type {};
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template <typename T>
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constexpr auto is_contiguous_v = is_contiguous<T>::value;
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namespace cruft {
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///////////////////////////////////////////////////////////////////////////////
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/// stores the type of '::value_type' for a given type, or the type itself if
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/// it does not have such a type.
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template <typename ValueT, typename = std::void_t<>>
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struct inner_type {
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using type = ValueT;
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};
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//-----------------------------------------------------------------------------
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template <typename ValueT>
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struct inner_type<
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ValueT,
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std::void_t<typename ValueT::value_type>
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> {
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using type = typename ValueT::value_type;
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};
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//-----------------------------------------------------------------------------
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template <typename ValueT>
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using inner_type_t = typename inner_type<ValueT>::type;
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}
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///////////////////////////////////////////////////////////////////////////////
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template <
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template <typename...> class TemplateT,
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typename QueryT
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>
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struct is_same_template_template : public std::false_type {};
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//-----------------------------------------------------------------------------
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template <
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template <typename...> class TemplateT,
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template <typename...> class QueryT,
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typename ...Args
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> struct is_same_template_template<
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TemplateT,
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QueryT<Args...>
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> : public std::conditional_t<
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std::is_same_v<
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TemplateT<Args...>,
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QueryT<Args...>
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>,
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std::true_type,
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std::false_type
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> { };
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//-----------------------------------------------------------------------------
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template <template <typename...> class TemplateT, typename QueryT>
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constexpr auto is_same_template_template_v = is_same_template_template<TemplateT,QueryT>::value;
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namespace cruft::traits {
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/// combines an abitrary sequence of type traits into one result
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template <
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typename ValueT,
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template <typename> class ...Traits
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> struct all : public std::integral_constant<
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bool,
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(Traits<ValueT>::value && ...)
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> { };
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};
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///////////////////////////////////////////////////////////////////////////////
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namespace cruft {
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/// tests if the type is a signed integer type
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template <typename ValueT>
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struct is_signed_integral : public traits::all<
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ValueT, std::is_signed, std::is_integral
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> { };
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template <typename ValueT>
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constexpr auto is_signed_integral_v = is_signed_integral<ValueT>::value;
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/// tests if the type is an unsigned integer type
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template <typename ValueT>
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struct is_unsigned_integral : public traits::all<
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ValueT, std::is_unsigned, std::is_integral
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> { };
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template <typename ValueT>
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constexpr auto is_unsigned_integral_v = is_unsigned_integral<ValueT>::value;
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/// tests if the type has the same basic fundamental type.
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///
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/// ie, both float, signed, unsigned, or char.
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template <typename ValueA, typename ValueB>
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struct is_same_basic_type {
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static constexpr bool value =
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(std::is_floating_point_v<ValueA> && std::is_floating_point_v<ValueB>) ||
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(is_unsigned_integral_v<ValueA> && is_unsigned_integral_v<ValueB>) ||
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(is_signed_integral_v<ValueA> && is_signed_integral_v<ValueB>) ||
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(std::is_same_v<char,ValueA> && std::is_same_v<char,ValueB>);
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};
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template <typename ValueA, typename ValueB>
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constexpr auto is_same_basic_type_v = is_same_basic_type<ValueA,ValueB>::value;
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}
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#endif
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