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// Copyright 2017 Elias Kosunen
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// This file is a part of scnlib:
// https://github.com/eliaskosunen/scnlib
//
// The contents of this file are adapted from NanoRange.
// https://github.com/tcbrindle/NanoRange
// Copyright (c) 2018 Tristan Brindle
// Distributed under the Boost Software License, Version 1.0
#ifndef SCN_RANGES_UTIL_H
#define SCN_RANGES_UTIL_H
#include "../util/meta.h"
namespace scn {
SCN_BEGIN_NAMESPACE
namespace custom_ranges {
namespace detail {
template <size_t N>
using priority_tag = ::scn::detail::priority_tag<N>;
template <typename... Ts>
using void_t = ::scn::detail::void_t<Ts...>;
template <typename T>
using static_const = ::scn::detail::static_const<T>;
template <typename T>
using remove_cvref_t = ::scn::detail::remove_cvref_t<T>;
template <typename T>
constexpr typename std::decay<T>::type decay_copy(T&& t) noexcept(
noexcept(static_cast<typename std::decay<T>::type>(SCN_FWD(t))))
{
return SCN_FWD(t);
}
struct nonesuch {
nonesuch() = delete;
nonesuch(nonesuch const&) = delete;
nonesuch& operator=(const nonesuch&) = delete;
~nonesuch() = delete;
};
template <typename Void,
template <class...>
class Trait,
typename... Args>
struct test {
using type = nonesuch;
};
template <template <class...> class Trait, typename... Args>
struct test<void_t<Trait<Args...>>, Trait, Args...> {
using type = Trait<Args...>;
};
template <template <class...> class Trait, typename... Args>
using test_t = typename test<void, Trait, Args...>::type;
template <typename Void,
template <class...>
class AliasT,
typename... Args>
struct exists_helper : std::false_type {
};
template <template <class...> class AliasT, typename... Args>
struct exists_helper<void_t<AliasT<Args...>>, AliasT, Args...>
: std::true_type {
};
template <template <class...> class AliasT, typename... Args>
struct exists : exists_helper<void, AliasT, Args...> {
};
template <typename R,
typename... Args,
typename = decltype(&R::template _test_requires<Args...>)>
auto test_requires(R&) -> void;
template <typename R, typename... Args>
using test_requires_t =
decltype(test_requires<R, Args...>(SCN_DECLVAL(R&)));
template <typename R, typename... Args>
struct _requires : exists<test_requires_t, R, Args...> {
};
template <bool Expr>
using requires_expr = typename std::enable_if<Expr, int>::type;
template <typename...>
struct get_common_type;
template <typename T, typename U>
struct copy_cv {
using type = U;
};
template <typename T, typename U>
struct copy_cv<const T, U> {
using type = typename std::add_const<U>::type;
};
template <typename T, typename U>
struct copy_cv<volatile T, U> {
using type = typename std::add_volatile<U>::type;
};
template <typename T, typename U>
struct copy_cv<const volatile T, U> {
using type = typename std::add_cv<U>::type;
};
template <typename T, typename U>
using copy_cv_t = typename copy_cv<T, U>::type;
template <typename T>
using cref_t = typename std::add_lvalue_reference<
const typename std::remove_reference<T>::type>::type;
template <typename T>
struct rref_res {
using type = T;
};
template <typename T>
struct rref_res<T&> {
using type = typename std::remove_reference<T>::type&&;
};
template <typename T>
using rref_res_t = typename rref_res<T>::type;
template <typename T, typename U>
using cond_res_t =
decltype(SCN_DECLVAL(bool) ? std::declval<T (&)()>()()
: std::declval<U (&)()>()());
template <typename T, typename U>
struct simple_common_reference {
};
template <
typename T,
typename U,
typename C =
test_t<cond_res_t, copy_cv_t<T, U>&, copy_cv_t<U, T>&>>
struct lvalue_simple_common_reference
: std::enable_if<std::is_reference<C>::value, C> {
};
template <typename T, typename U>
using lvalue_scr_t =
typename lvalue_simple_common_reference<T, U>::type;
template <typename T, typename U>
struct simple_common_reference<T&, U&>
: lvalue_simple_common_reference<T, U> {
};
template <typename T,
typename U,
typename LCR = test_t<lvalue_scr_t, T, U>,
typename C = rref_res_t<LCR>>
struct rvalue_simple_common_reference
: std::enable_if<std::is_convertible<T&&, C>::value &&
std::is_convertible<U&&, C>::value>::type {
};
template <typename T, typename U>
struct simple_common_reference<T&&, U&&>
: rvalue_simple_common_reference<T, U> {
};
template <typename A,
typename B,
typename C = test_t<lvalue_scr_t, A, const B>>
struct mixed_simple_common_reference
: std::enable_if<std::is_convertible<B&&, C>::value, C>::type {
};
template <typename A, typename B>
struct simple_common_reference<A&, B&&>
: mixed_simple_common_reference<A, B> {
};
template <typename A, typename B>
struct simple_common_reference<A&&, B&>
: simple_common_reference<B&&, A&> {
};
template <typename T, typename U>
using simple_common_reference_t =
typename simple_common_reference<T, U>::type;
template <typename>
struct xref {
template <typename U>
using type = U;
};
template <typename A>
struct xref<A&> {
template <typename U>
using type = typename std::add_lvalue_reference<
typename xref<A>::template type<U>>::type;
};
template <typename A>
struct xref<A&&> {
template <typename U>
using type = typename std::add_rvalue_reference<
typename xref<A>::template type<U>>::type;
};
template <typename A>
struct xref<const A> {
template <typename U>
using type = typename std::add_const<
typename xref<A>::template type<U>>::type;
};
template <typename A>
struct xref<volatile A> {
template <typename U>
using type = typename std::add_volatile<
typename xref<A>::template type<U>>::type;
};
template <typename A>
struct xref<const volatile A> {
template <typename U>
using type = typename std::add_cv<
typename xref<A>::template type<U>>::type;
};
template <typename T,
typename U,
template <class>
class TQual,
template <class>
class UQual>
struct basic_common_reference {
};
template <typename...>
struct get_common_reference;
template <typename... Ts>
using get_common_reference_t =
typename get_common_reference<Ts...>::type;
template <>
struct get_common_reference<> {
};
template <typename T0>
struct get_common_reference<T0> {
using type = T0;
};
template <typename T, typename U>
struct has_simple_common_ref
: exists<simple_common_reference_t, T, U> {
};
template <typename T, typename U>
using basic_common_ref_t = typename basic_common_reference<
::scn::detail::remove_cvref_t<T>,
::scn::detail::remove_cvref_t<U>,
xref<T>::template type,
xref<U>::template type>::type;
template <typename T, typename U>
struct has_basic_common_ref : exists<basic_common_ref_t, T, U> {
};
template <typename T, typename U>
struct has_cond_res : exists<cond_res_t, T, U> {
};
template <typename T, typename U, typename = void>
struct binary_common_ref : get_common_type<T, U> {
};
template <typename T, typename U>
struct binary_common_ref<
T,
U,
typename std::enable_if<
has_simple_common_ref<T, U>::value>::type>
: simple_common_reference<T, U> {
};
template <typename T, typename U>
struct binary_common_ref<
T,
U,
typename std::enable_if<
has_basic_common_ref<T, U>::value &&
!has_simple_common_ref<T, U>::value>::type> {
using type = basic_common_ref_t<T, U>;
};
template <typename T, typename U>
struct binary_common_ref<
T,
U,
typename std::enable_if<
has_cond_res<T, U>::value &&
!has_basic_common_ref<T, U>::value &&
!has_simple_common_ref<T, U>::value>::type> {
using type = cond_res_t<T, U>;
};
template <typename T1, typename T2>
struct get_common_reference<T1, T2> : binary_common_ref<T1, T2> {
};
template <typename Void, typename T1, typename T2, typename... Rest>
struct multiple_common_reference {
};
template <typename T1, typename T2, typename... Rest>
struct multiple_common_reference<
void_t<get_common_reference_t<T1, T2>>,
T1,
T2,
Rest...> : get_common_reference<get_common_reference_t<T1, T2>,
Rest...> {
};
template <typename T1, typename T2, typename... Rest>
struct get_common_reference<T1, T2, Rest...>
: multiple_common_reference<void, T1, T2, Rest...> {
};
template <typename... Ts>
using get_common_type_t = typename get_common_type<Ts...>::type;
template <typename T, typename U>
struct _same_decayed
: std::integral_constant<
bool,
std::is_same<T, typename std::decay<T>::type>::value &&
std::is_same<U,
typename std::decay<U>::type>::value> {
};
template <typename T, typename U>
using ternary_return_t =
typename std::decay<decltype(false ? SCN_DECLVAL(T)
: SCN_DECLVAL(U))>::type;
template <typename, typename, typename = void>
struct binary_common_type {
};
template <typename T, typename U>
struct binary_common_type<
T,
U,
typename std::enable_if<!_same_decayed<T, U>::value>::type>
: get_common_type<typename std::decay<T>::type,
typename std::decay<U>::type> {
};
template <typename T, typename U>
struct binary_common_type<
T,
U,
typename std::enable_if<
_same_decayed<T, U>::value &&
exists<ternary_return_t, T, U>::value>::type> {
using type = ternary_return_t<T, U>;
};
template <typename T, typename U>
struct binary_common_type<
T,
U,
typename std::enable_if<
_same_decayed<T, U>::value &&
!exists<ternary_return_t, T, U>::value &&
exists<cond_res_t, cref_t<T>, cref_t<U>>::value>::type> {
using type =
typename std::decay<cond_res_t<cref_t<T>, cref_t<U>>>::type;
};
template <>
struct get_common_type<> {
};
template <typename T>
struct get_common_type<T> : get_common_type<T, T> {
};
template <typename T, typename U>
struct get_common_type<T, U> : binary_common_type<T, U> {
};
template <typename Void, typename...>
struct multiple_common_type {
};
template <typename T1, typename T2, typename... R>
struct multiple_common_type<void_t<get_common_type_t<T1, T2>>,
T1,
T2,
R...>
: get_common_type<get_common_type_t<T1, T2>, R...> {
};
template <typename T1, typename T2, typename... R>
struct get_common_type<T1, T2, R...>
: multiple_common_type<void, T1, T2, R...> {
};
} // namespace detail
} // namespace custom_ranges
SCN_END_NAMESPACE
} // namespace scn
#endif // SCN_RANGES_UTIL_H
|
