mirror of https://github.com/axmolengine/axmol.git
305 lines
11 KiB
C++
305 lines
11 KiB
C++
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/// \file
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// Range v3 library
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//
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// Copyright Eric Niebler 2013-present
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// Copyright Casey Carter 2016
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//
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// Use, modification and distribution is subject to the
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// Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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//
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// Project home: https://github.com/ericniebler/range-v3
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//
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#ifndef RANGES_V3_ITERATOR_ACCESS_HPP
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#define RANGES_V3_ITERATOR_ACCESS_HPP
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#include <iterator>
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#include <type_traits>
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#include <utility>
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#include <std/detail/associated_types.hpp>
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#include <meta/meta.hpp>
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#include <concepts/concepts.hpp>
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#include <range/v3/range_fwd.hpp>
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#include <range/v3/utility/move.hpp>
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#include <range/v3/utility/static_const.hpp>
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#include <range/v3/utility/swap.hpp>
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#include <range/v3/detail/prologue.hpp>
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namespace ranges
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{
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/// \addtogroup group-iterator
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/// @{
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/// \cond
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namespace detail
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{
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template<typename I,
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#ifdef RANGES_WORKAROUND_MSVC_683388
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typename R = meta::conditional_t<
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std::is_pointer<uncvref_t<I>>::value &&
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std::is_array<std::remove_pointer_t<uncvref_t<I>>>::value,
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std::add_lvalue_reference_t<std::remove_pointer_t<uncvref_t<I>>>,
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decltype(*std::declval<I &>())>,
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#else
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typename R = decltype(*std::declval<I &>()),
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#endif
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typename = R &>
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using iter_reference_t_ = R;
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#if defined(RANGES_DEEP_STL_INTEGRATION) && RANGES_DEEP_STL_INTEGRATION && \
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!defined(RANGES_DOXYGEN_INVOKED)
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template<typename T>
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using iter_value_t_ =
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typename meta::conditional_t<
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is_std_iterator_traits_specialized_v<T>,
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std::iterator_traits<T>,
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indirectly_readable_traits<T>>::value_type;
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#else
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template<typename T>
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using iter_value_t_ = typename indirectly_readable_traits<T>::value_type;
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#endif
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} // namespace detail
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/// \endcond
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template<typename R>
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using iter_reference_t = detail::iter_reference_t_<R>;
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template<typename R>
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using iter_value_t = detail::iter_value_t_<uncvref_t<R>>;
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/// \cond
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namespace _iter_move_
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{
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#if RANGES_BROKEN_CPO_LOOKUP
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void iter_move(); // unqualified name lookup block
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#endif
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template<typename T>
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decltype(iter_move(std::declval<T>())) try_adl_iter_move_(int);
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template<typename T>
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void try_adl_iter_move_(long);
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template<typename T>
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RANGES_INLINE_VAR constexpr bool is_adl_indirectly_movable_v =
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!RANGES_IS_SAME(void, decltype(_iter_move_::try_adl_iter_move_<T>(42)));
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struct fn
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{
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// clang-format off
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template<typename I,
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typename = detail::enable_if_t<is_adl_indirectly_movable_v<I &>>>
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#ifndef RANGES_WORKAROUND_CLANG_23135
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constexpr
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#endif // RANGES_WORKAROUND_CLANG_23135
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auto CPP_auto_fun(operator())(I &&i)(const)
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(
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return iter_move(i)
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)
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template<
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typename I,
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typename = detail::enable_if_t<!is_adl_indirectly_movable_v<I &>>,
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typename R = iter_reference_t<I>>
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#ifndef RANGES_WORKAROUND_CLANG_23135
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constexpr
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#endif // RANGES_WORKAROUND_CLANG_23135
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auto CPP_auto_fun(operator())(I &&i)(const)
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(
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return static_cast<aux::move_t<R>>(aux::move(*i))
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)
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// clang-format on
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};
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} // namespace _iter_move_
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/// \endcond
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RANGES_DEFINE_CPO(_iter_move_::fn, iter_move)
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/// \cond
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namespace detail
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{
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template<typename I, typename O>
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auto is_indirectly_movable_(I & (*i)(), O & (*o)(), iter_value_t<I> * v = nullptr)
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-> always_<std::true_type,
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decltype(iter_value_t<I>(iter_move(i()))),
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decltype(*v = iter_move(i())),
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decltype(*o() = (iter_value_t<I> &&) * v),
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decltype(*o() = iter_move(i()))>;
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template<typename I, typename O>
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auto is_indirectly_movable_(...) -> std::false_type;
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template<typename I, typename O>
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auto is_nothrow_indirectly_movable_(iter_value_t<I> * v) -> meta::bool_<
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noexcept(iter_value_t<I>(iter_move(std::declval<I &>()))) &&
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noexcept(*v = iter_move(std::declval<I &>())) &&
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noexcept(*std::declval<O &>() = (iter_value_t<I> &&) * v) &&
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noexcept(*std::declval<O &>() = iter_move(std::declval<I &>()))>;
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template<typename I, typename O>
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auto is_nothrow_indirectly_movable_(...) -> std::false_type;
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} // namespace detail
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/// \endcond
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template<typename I, typename O>
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RANGES_INLINE_VAR constexpr bool is_indirectly_movable_v =
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decltype(detail::is_indirectly_movable_<I, O>(nullptr, nullptr))::value;
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template<typename I, typename O>
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RANGES_INLINE_VAR constexpr bool is_nothrow_indirectly_movable_v =
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decltype(detail::is_nothrow_indirectly_movable_<I, O>(nullptr))::value;
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template<typename I, typename O>
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struct is_indirectly_movable : meta::bool_<is_indirectly_movable_v<I, O>>
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{};
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template<typename I, typename O>
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struct is_nothrow_indirectly_movable
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: meta::bool_<is_nothrow_indirectly_movable_v<I, O>>
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{};
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/// \cond
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namespace _iter_swap_
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{
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struct nope
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{};
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// Q: Should std::reference_wrapper be considered a proxy wrt swapping rvalues?
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// A: No. Its operator= is currently defined to reseat the references, so
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// std::swap(ra, rb) already means something when ra and rb are (lvalue)
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// reference_wrappers. That reseats the reference wrappers but leaves the
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// referents unmodified. Treating rvalue reference_wrappers differently would
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// be confusing.
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// Q: Then why is it OK to "re"-define swap for pairs and tuples of references?
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// A: Because as defined above, swapping an rvalue tuple of references has the
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// same semantics as swapping an lvalue tuple of references. Rather than
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// reseat the references, assignment happens *through* the references.
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// Q: But I have an iterator whose operator* returns an rvalue
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// std::reference_wrapper<T>. How do I make it model indirectly_swappable?
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// A: With an overload of iter_swap.
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// Intentionally create an ambiguity with std::iter_swap, which is
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// unconstrained.
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template<typename T, typename U>
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nope iter_swap(T, U) = delete;
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#ifdef RANGES_WORKAROUND_MSVC_895622
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nope iter_swap();
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#endif
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template<typename T, typename U>
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decltype(iter_swap(std::declval<T>(), std::declval<U>())) try_adl_iter_swap_(int);
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template<typename T, typename U>
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nope try_adl_iter_swap_(long);
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// Test whether an overload of iter_swap for a T and a U can be found
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// via ADL with the iter_swap overload above participating in the
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// overload set. This depends on user-defined iter_swap overloads
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// being a better match than the overload in namespace std.
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template<typename T, typename U>
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RANGES_INLINE_VAR constexpr bool is_adl_indirectly_swappable_v =
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!RANGES_IS_SAME(nope, decltype(_iter_swap_::try_adl_iter_swap_<T, U>(42)));
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struct fn
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{
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// *If* a user-defined iter_swap is found via ADL, call that:
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template<typename T, typename U>
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constexpr detail::enable_if_t<is_adl_indirectly_swappable_v<T, U>> operator()(
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T && t, U && u) const noexcept(noexcept(iter_swap((T &&) t, (U &&) u)))
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{
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(void)iter_swap((T &&) t, (U &&) u);
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}
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// *Otherwise*, for readable types with swappable reference
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// types, call ranges::swap(*a, *b)
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template<typename I0, typename I1>
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constexpr detail::enable_if_t<
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!is_adl_indirectly_swappable_v<I0, I1> &&
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is_swappable_with<iter_reference_t<I0>, iter_reference_t<I1>>::value>
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operator()(I0 && a, I1 && b) const noexcept(noexcept(ranges::swap(*a, *b)))
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{
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ranges::swap(*a, *b);
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}
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// *Otherwise*, for readable types that are mutually
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// indirectly_movable_storable, implement as:
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// iter_value_t<T0> tmp = iter_move(a);
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// *a = iter_move(b);
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// *b = std::move(tmp);
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template<typename I0, typename I1>
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constexpr detail::enable_if_t<
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!is_adl_indirectly_swappable_v<I0, I1> &&
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!is_swappable_with<iter_reference_t<I0>, iter_reference_t<I1>>::value &&
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is_indirectly_movable_v<I0, I1> && is_indirectly_movable_v<I1, I0>>
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operator()(I0 && a, I1 && b) const
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noexcept(is_nothrow_indirectly_movable_v<I0, I1> &&
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is_nothrow_indirectly_movable_v<I1, I0>)
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{
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iter_value_t<I0> v0 = iter_move(a);
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*a = iter_move(b);
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*b = detail::move(v0);
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}
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};
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} // namespace _iter_swap_
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/// \endcond
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/// \relates _iter_swap_::fn
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RANGES_DEFINE_CPO(_iter_swap_::fn, iter_swap)
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/// \cond
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namespace detail
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{
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template<typename T, typename U>
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auto is_indirectly_swappable_(T & (*t)(), U & (*u)())
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-> detail::always_<std::true_type, decltype(iter_swap(t(), u()))>;
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template<typename T, typename U>
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auto is_indirectly_swappable_(...) -> std::false_type;
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template<typename T, typename U>
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auto is_nothrow_indirectly_swappable_(int)
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-> meta::bool_<noexcept(iter_swap(std::declval<T &>(), std::declval<U &>()))>;
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template<typename T, typename U>
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auto is_nothrow_indirectly_swappable_(long) -> std::false_type;
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} // namespace detail
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/// \endcond
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template<typename T, typename U>
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RANGES_INLINE_VAR constexpr bool is_indirectly_swappable_v =
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decltype(detail::is_indirectly_swappable_<T, U>(nullptr, nullptr))::value;
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template<typename T, typename U>
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RANGES_INLINE_VAR constexpr bool is_nothrow_indirectly_swappable_v =
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decltype(detail::is_nothrow_indirectly_swappable_<T, U>(0))::value;
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template<typename T, typename U>
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struct is_indirectly_swappable : meta::bool_<is_indirectly_swappable_v<T, U>>
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{};
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template<typename T, typename U>
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struct is_nothrow_indirectly_swappable
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: meta::bool_<is_nothrow_indirectly_swappable_v<T, U>>
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{};
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namespace cpp20
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{
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using ranges::iter_move;
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using ranges::iter_reference_t;
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using ranges::iter_swap;
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using ranges::iter_value_t;
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} // namespace cpp20
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/// @}
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} // namespace ranges
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#include <range/v3/detail/epilogue.hpp>
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#endif // RANGES_V3_ITERATOR_ACCESS_HPP
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