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// Range v3 library
//
// Copyright Eric Niebler 2018-present
//
// Use, modification and distribution is subject to the
// Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
// Project home: https://github.com/ericniebler/range-v3
//
#ifndef RANGES_V3_STD_ITERATOR
#define RANGES_V3_STD_ITERATOR
#if defined(__GNUC__)
#include_next <iterator>
#elif defined(_MSC_VER)
#include <../include/iterator> // HACKHACK
#else
#error "Cannot use range-v3 STL deep integration on this platform."
#endif
#if RANGES_DEEP_STL_INTEGRATION
#include <range/v3/detail/config.hpp>
#include <std/detail/associated_types.hpp>
#include <range/v3/detail/prologue.hpp>
namespace ranges
{
template<typename I>
struct incrementable_traits;
template<typename I>
struct indirectly_readable_traits;
/// \cond
namespace detail
{
template<typename I>
typename incrementable_traits<I>::difference_type cpp17_difference_type_(int);
template<typename I>
void cpp17_difference_type_(long);
template<typename I>
typename I::pointer cpp17_pointer_type_(int);
template<typename I>
auto cpp17_pointer_type_(long, I *pi = nullptr) -> decltype(pi->operator->());
template<typename I>
void cpp17_pointer_type_(...);
template<typename I>
typename I::reference cpp17_reference_type_(int);
template<typename I>
auto cpp17_reference_type_(long, I *pi = nullptr) -> decltype(**pi);
template<typename I>
auto cpp17_iterator_category_4_(long)
{
return std::bidirectional_iterator_tag{};
}
// Satisfies Cpp17RandomAccessIterator?
template<typename I>
auto cpp17_iterator_category_4_(
int,
I *pi = nullptr,
typename incrementable_traits<I>::difference_type d = 0,
always_<
void,
int[RANGES_IS_SAME(decltype(*pi += d), I &)],
int[RANGES_IS_SAME(decltype(*pi -= d), I &)],
int[RANGES_IS_SAME(decltype(*pi + d), I)],
int[RANGES_IS_SAME(decltype(*pi - d), I)],
int[RANGES_IS_SAME(decltype(d + *pi), I)],
int[RANGES_IS_SAME(decltype(*pi - *pi), decltype(d))],
int[RANGES_IS_SAME(decltype((*pi)[d]), decltype(**pi))],
decltype(*pi < *pi ? true : false),
decltype(*pi > *pi ? true : false),
decltype(*pi <= *pi ? true : false),
decltype(*pi >= *pi ? true : false)
> * = nullptr)
{
return std::random_access_iterator_tag{};
}
template<typename I>
auto cpp17_iterator_category_3_(long)
{
return std::forward_iterator_tag{};
}
// Satisfies Cpp17BidirectionalIterator?
template<typename I>
auto cpp17_iterator_category_3_(
int,
I *pi = nullptr,
void (*fn)(I const &) = nullptr,
always_<
void,
decltype(fn((*pi)--)), // i-- convertible to I const &
int[RANGES_IS_SAME(decltype(--*pi), I &)], // --i has type I &
// *i has the same type as *i--
int[RANGES_IS_SAME(decltype(**pi), decltype(*(*pi)--))]
> * = nullptr)
{
return cpp17_iterator_category_4_<I>(0);
}
template<typename I>
auto cpp17_iterator_category_2_(long)
{
return std::input_iterator_tag{};
}
// Satisfies Cpp17ForwardIterator?
template<typename I>
auto cpp17_iterator_category_2_(
int,
I *pi = nullptr,
void (*fn)(I const &) = nullptr,
typename indirectly_readable_traits<I>::value_type *pv = nullptr,
typename indirectly_readable_traits<I>::value_type const *pcv = nullptr,
always_<
void,
decltype(I{}), // Default constructible
decltype(fn((*pi)++)), // i++ convertible to I const &
// *i has the same type as *i++
int[RANGES_IS_SAME(decltype(**pi), decltype(*(*pi)++))],
// *i is a real reference to value_type
#ifdef RANGES_WORKAROUND_MSVC_793042
enable_if_t<RANGES_IS_SAME(decltype(**pi), decltype(*pv)) ||
RANGES_IS_SAME(decltype(**pi), decltype(*pcv)) ||
RANGES_IS_SAME(decltype(**pi), typename indirectly_readable_traits<I>::value_type &&) ||
RANGES_IS_SAME(decltype(**pi), typename indirectly_readable_traits<I>::value_type const &&)>
#else // ^^^ workaround / no workaround vvv
int[RANGES_IS_SAME(decltype(**pi), decltype(*pv)) ||
RANGES_IS_SAME(decltype(**pi), decltype(*pcv)) ||
RANGES_IS_SAME(decltype(**pi), typename indirectly_readable_traits<I>::value_type &&) ||
RANGES_IS_SAME(decltype(**pi), typename indirectly_readable_traits<I>::value_type const &&)]
#endif // RANGES_WORKAROUND_MSVC_793042
> * = nullptr)
{
return cpp17_iterator_category_3_<I>(0);
}
template<typename I>
using cpp17_readable_iterator_category_t =
decltype(detail::cpp17_iterator_category_2_<I>(0));
template<typename I>
auto cpp17_iterator_category_(long)
{
return cpp17_iterator_category_2_<I>(0);
}
// Explicitly declares its category?
template<typename I>
typename I::iterator_category cpp17_iterator_category_(int)
{
return {};
}
template<typename I>
auto std_iterator_traits_impl_2_(long)
{
return std_output_iterator_traits<
decltype(detail::cpp17_difference_type_<I>(0))>{};
}
// Satisfies Cpp17InputIterator?
template<typename I>
auto std_iterator_traits_impl_2_(
int,
I *pi = nullptr,
typename incrementable_traits<I>::difference_type d = 0,
typename indirectly_readable_traits<I>::value_type const *pcv = nullptr,
always_<
void,
int[decltype(d)(-1) < decltype(d)(0)], // signed difference type
decltype(decltype(*pcv)(**pi)), // sensible reference/value type
decltype(decltype(*pcv)(*(*pi)++)), // sensible post-increment result
decltype(*pi == *pi ? true : false), // equality comparable
decltype(*pi != *pi ? true : false) // " "
> * = nullptr)
{
using D = typename incrementable_traits<I>::difference_type;
struct yes_traits
{
using difference_type = D;
using value_type = typename indirectly_readable_traits<I>::value_type;
using reference = decltype(cpp17_reference_type_<I>(0));
using pointer = decltype(cpp17_pointer_type_<I>(0));
using iterator_category = decltype(cpp17_iterator_category_<I>(0));
};
struct no_traits
{};
return conditional_t<is_integral_<D>(0), yes_traits, no_traits>{};
}
template<typename I>
nil_ std_iterator_traits_impl_(long)
{
return {};
}
// Satisfies Cpp17Iterator?
template<typename I>
auto std_iterator_traits_impl_(
int,
I *pi = nullptr,
void (*nv)(...) = nullptr,
always_<
void,
decltype(nv(**pi)),
int[RANGES_IS_SAME(decltype(++*pi), I &)],
decltype(nv(*(*pi)++))
> * = nullptr)
{
return std_iterator_traits_impl_2_<I>(0);
}
template<typename T>
constexpr bool has_iterator_typedefs_impl_(
int,
always_<
void,
typename T::difference_type,
typename T::value_type,
typename T::pointer,
typename T::reference,
typename T::iterator_category
> * = nullptr)
{
return true;
}
template<typename T>
constexpr bool has_iterator_typedefs_impl_(long)
{
return false;
}
}
/// \endcond
} // namespace ranges
// Hijack the primary std::iterator_traits template from each of the 3 major
// standard library implementations
RANGES_BEGIN_NAMESPACE_STD
RANGES_BEGIN_NAMESPACE_VERSION
#if defined(__GLIBCXX__)
template<typename I>
struct __iterator_traits<
I,
::ranges::detail::enable_if_t<!::ranges::detail::has_iterator_typedefs_impl_<I>(0)>>
: decltype(::ranges::detail::std_iterator_traits_impl_<I>(0))
{};
#elif defined(_LIBCPP_VERSION)
template<typename I>
struct __iterator_traits<I, false> // doesn't have I::iterator_category
: decltype(::ranges::detail::std_iterator_traits_impl_<I>(0))
{};
#elif defined(_MSVC_STL_VERSION)
template<typename I>
struct _Iterator_traits_base<
I,
#ifdef RANGES_WORKAROUND_MSVC_792338
::ranges::detail::enable_if_t<decltype(bool_constant<
!::ranges::detail::has_iterator_typedefs_impl_<I>(0)>{})::value>>
#else // ^^^ workaround / no workaround vvv
::ranges::detail::enable_if_t<!::ranges::detail::has_iterator_typedefs_impl_<I>(0)>>
#endif // RANGES_WORKAROUND_MSVC_792338
: decltype(::ranges::detail::std_iterator_traits_impl_<I>(0))
{};
#endif
RANGES_END_NAMESPACE_VERSION
RANGES_END_NAMESPACE_STD
#include <range/v3/detail/epilogue.hpp>
#endif // RANGES_DEEP_STL_INTEGRATION
#endif // RANGES_V3_STD_ITERATOR
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