79 lines
3.1 KiB
C++

// -*- 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___FLAT_SET_UTILS_H
#define _LIBCPP___FLAT_SET_UTILS_H
#include <__config>
#include <__ranges/access.h>
#include <__ranges/concepts.h>
#include <__type_traits/container_traits.h>
#include <__type_traits/decay.h>
#include <__utility/exception_guard.h>
#include <__utility/forward.h>
#include <__utility/move.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
#if _LIBCPP_STD_VER >= 23
_LIBCPP_BEGIN_NAMESPACE_STD
// These utilities are defined in a class instead of a namespace so that this class can be befriended more easily.
struct __flat_set_utils {
// Emplace a key into a flat_{multi}set, at the exact position that
// __it point to, assuming that the key is not already present in the set.
// When an exception is thrown during the emplacement, the function will clear the set if the container does not
// have strong exception safety guarantee on emplacement.
template <class _Set, class _Iter, class _KeyArg>
_LIBCPP_HIDE_FROM_ABI static auto __emplace_exact_pos(_Set& __set, _Iter&& __iter, _KeyArg&& __key) {
using _KeyContainer = typename decay_t<_Set>::container_type;
auto __on_failure = std::__make_exception_guard([&]() noexcept {
if constexpr (!__container_traits<_KeyContainer>::__emplacement_has_strong_exception_safety_guarantee) {
__set.clear() /* noexcept */;
}
});
auto __key_it = __set.__keys_.emplace(__iter.__base(), std::forward<_KeyArg>(__key));
__on_failure.__complete();
return typename decay_t<_Set>::iterator(std::move(__key_it));
}
template <class _Set, class _InputIterator>
_LIBCPP_HIDE_FROM_ABI static void __append(_Set& __set, _InputIterator __first, _InputIterator __last) {
__set.__keys_.insert(__set.__keys_.end(), std::move(__first), std::move(__last));
}
template <class _Set, class _Range>
_LIBCPP_HIDE_FROM_ABI static void __append(_Set& __set, _Range&& __rng) {
if constexpr (requires { __set.__keys_.insert_range(__set.__keys_.end(), std::forward<_Range>(__rng)); }) {
// C++23 Sequence Container should have insert_range member function
// Note that not all Sequence Containers provide append_range.
__set.__keys_.insert_range(__set.__keys_.end(), std::forward<_Range>(__rng));
} else if constexpr (ranges::common_range<_Range>) {
__set.__keys_.insert(__set.__keys_.end(), ranges::begin(__rng), ranges::end(__rng));
} else {
for (auto&& __x : __rng) {
__set.__keys_.insert(__set.__keys_.end(), std::forward<decltype(__x)>(__x));
}
}
}
};
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP_STD_VER >= 23
_LIBCPP_POP_MACROS
#endif // #define _LIBCPP___FLAT_SET_UTILS_H