llvm-project/libcxx/include/__ranges/view_interface.h

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// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___RANGES_VIEW_INTERFACE_H
#define _LIBCPP___RANGES_VIEW_INTERFACE_H
#include <__config>
#include <__iterator/concepts.h>
#include <__iterator/iterator_traits.h>
#include <__iterator/prev.h>
#include <__ranges/access.h>
#include <__ranges/empty.h>
#include <__ranges/view.h>
#include <type_traits>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
_LIBCPP_BEGIN_NAMESPACE_STD
#if !defined(_LIBCPP_HAS_NO_RANGES)
namespace ranges {
template<class _Tp>
concept __can_empty = requires(_Tp __t) { ranges::empty(__t); };
template<class _Tp>
void __implicitly_convert_to(type_identity_t<_Tp>) noexcept;
template<class _Derived>
requires is_class_v<_Derived> && same_as<_Derived, remove_cv_t<_Derived>>
class view_interface : public view_base {
constexpr _Derived& __derived() noexcept {
return static_cast<_Derived&>(*this);
}
constexpr _Derived const& __derived() const noexcept {
return static_cast<_Derived const&>(*this);
}
public:
template<class _D2 = _Derived>
[[nodiscard]] constexpr bool empty()
noexcept(noexcept(__implicitly_convert_to<bool>(ranges::begin(__derived()) == ranges::end(__derived()))))
requires forward_range<_D2>
{
return ranges::begin(__derived()) == ranges::end(__derived());
}
template<class _D2 = _Derived>
[[nodiscard]] constexpr bool empty() const
noexcept(noexcept(__implicitly_convert_to<bool>(ranges::begin(__derived()) == ranges::end(__derived()))))
requires forward_range<const _D2>
{
return ranges::begin(__derived()) == ranges::end(__derived());
}
template<class _D2 = _Derived>
constexpr explicit operator bool()
noexcept(noexcept(ranges::empty(declval<_D2>())))
requires __can_empty<_D2>
{
return !ranges::empty(__derived());
}
template<class _D2 = _Derived>
constexpr explicit operator bool() const
noexcept(noexcept(ranges::empty(declval<const _D2>())))
requires __can_empty<const _D2>
{
return !ranges::empty(__derived());
}
template<class _D2 = _Derived>
constexpr auto data()
noexcept(noexcept(_VSTD::to_address(ranges::begin(__derived()))))
requires contiguous_iterator<iterator_t<_D2>>
{
return _VSTD::to_address(ranges::begin(__derived()));
}
template<class _D2 = _Derived>
constexpr auto data() const
noexcept(noexcept(_VSTD::to_address(ranges::begin(__derived()))))
requires range<const _D2> && contiguous_iterator<iterator_t<const _D2>>
{
return _VSTD::to_address(ranges::begin(__derived()));
}
template<class _D2 = _Derived>
constexpr auto size()
noexcept(noexcept(ranges::end(__derived()) - ranges::begin(__derived())))
requires forward_range<_D2>
&& sized_sentinel_for<sentinel_t<_D2>, iterator_t<_D2>>
{
return ranges::end(__derived()) - ranges::begin(__derived());
}
template<class _D2 = _Derived>
constexpr auto size() const
noexcept(noexcept(ranges::end(__derived()) - ranges::begin(__derived())))
requires forward_range<const _D2>
&& sized_sentinel_for<sentinel_t<const _D2>, iterator_t<const _D2>>
{
return ranges::end(__derived()) - ranges::begin(__derived());
}
template<class _D2 = _Derived>
constexpr decltype(auto) front()
noexcept(noexcept(*ranges::begin(__derived())))
requires forward_range<_D2>
{
_LIBCPP_ASSERT(!empty(),
"Precondition `!empty()` not satisfied. `.front()` called on an empty view.");
return *ranges::begin(__derived());
}
template<class _D2 = _Derived>
constexpr decltype(auto) front() const
noexcept(noexcept(*ranges::begin(__derived())))
requires forward_range<const _D2>
{
_LIBCPP_ASSERT(!empty(),
"Precondition `!empty()` not satisfied. `.front()` called on an empty view.");
return *ranges::begin(__derived());
}
template<class _D2 = _Derived>
constexpr decltype(auto) back()
noexcept(noexcept(*ranges::prev(ranges::end(__derived()))))
requires bidirectional_range<_D2> && common_range<_D2>
{
_LIBCPP_ASSERT(!empty(),
"Precondition `!empty()` not satisfied. `.back()` called on an empty view.");
return *ranges::prev(ranges::end(__derived()));
}
template<class _D2 = _Derived>
constexpr decltype(auto) back() const
noexcept(noexcept(*ranges::prev(ranges::end(__derived()))))
requires bidirectional_range<const _D2> && common_range<const _D2>
{
_LIBCPP_ASSERT(!empty(),
"Precondition `!empty()` not satisfied. `.back()` called on an empty view.");
return *ranges::prev(ranges::end(__derived()));
}
template<random_access_range _RARange = _Derived>
constexpr decltype(auto) operator[](range_difference_t<_RARange> __index)
noexcept(noexcept(ranges::begin(__derived())[__index]))
{
return ranges::begin(__derived())[__index];
}
template<random_access_range _RARange = const _Derived>
constexpr decltype(auto) operator[](range_difference_t<_RARange> __index) const
noexcept(noexcept(ranges::begin(__derived())[__index]))
{
return ranges::begin(__derived())[__index];
}
};
}
#endif // !defined(_LIBCPP_HAS_NO_RANGES)
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_POP_MACROS
#endif // _LIBCPP___RANGES_VIEW_INTERFACE_H