axmol/thirdparty/range-v3/include/range/v3/iterator/unreachable_sentinel.hpp

71 lines
2.0 KiB
C++

/// \file
// Range v3 library
//
// Copyright Eric Niebler 2014-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_ITERATOR_UNREACHABLE_SENTINEL_HPP
#define RANGES_V3_ITERATOR_UNREACHABLE_SENTINEL_HPP
#include <range/v3/range_fwd.hpp>
#include <range/v3/iterator/concepts.hpp>
#include <range/v3/detail/prologue.hpp>
namespace ranges
{
/// \addtogroup group-iterator
/// @{
struct unreachable_sentinel_t
{
template<typename I>
friend constexpr auto operator==(I const &, unreachable_sentinel_t) noexcept
-> CPP_broken_friend_ret(bool)(
requires weakly_incrementable<I>)
{
return false;
}
template<typename I>
friend constexpr auto operator==(unreachable_sentinel_t, I const &) noexcept
-> CPP_broken_friend_ret(bool)(
requires weakly_incrementable<I>)
{
return false;
}
template<typename I>
friend constexpr auto operator!=(I const &, unreachable_sentinel_t) noexcept
-> CPP_broken_friend_ret(bool)(
requires weakly_incrementable<I>)
{
return true;
}
template<typename I>
friend constexpr auto operator!=(unreachable_sentinel_t, I const &) noexcept
-> CPP_broken_friend_ret(bool)(
requires weakly_incrementable<I>)
{
return true;
}
};
RANGES_INLINE_VARIABLE(unreachable_sentinel_t, unreachable)
namespace cpp20
{
using ranges::unreachable;
using ranges::unreachable_sentinel_t;
} // namespace cpp20
/// @}
} // namespace ranges
#include <range/v3/detail/epilogue.hpp>
#endif // RANGES_V3_ITERATOR_UNREACHABLE_SENTINEL_HPP