xref: /openbsd/gnu/llvm/libcxx/include/__algorithm/ranges_lexicographical_compare.h (revision 4bdff4be)

//===----------------------------------------------------------------------===//
//
// 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___ALGORITHM_RANGES_LEXICOGRAPHICAL_COMPARE_H
#define _LIBCPP___ALGORITHM_RANGES_LEXICOGRAPHICAL_COMPARE_H

#include <__config>
#include <__functional/identity.h>
#include <__functional/invoke.h>
#include <__functional/ranges_operations.h>
#include <__iterator/concepts.h>
#include <__iterator/projected.h>
#include <__ranges/access.h>
#include <__ranges/concepts.h>
#include <__utility/move.h>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#  pragma GCC system_header
#endif

#if _LIBCPP_STD_VER > 17

_LIBCPP_BEGIN_NAMESPACE_STD

namespace ranges {
namespace __lexicographical_compare {
struct __fn {

  template <class _Iter1, class _Sent1, class _Iter2, class _Sent2, class _Proj1, class _Proj2, class _Comp>
  _LIBCPP_HIDE_FROM_ABI constexpr static
  bool __lexicographical_compare_impl(_Iter1 __first1, _Sent1 __last1,
                                      _Iter2 __first2, _Sent2 __last2,
                                      _Comp& __comp,
                                      _Proj1& __proj1,
                                      _Proj2& __proj2) {
    while (__first2 != __last2) {
      if (__first1 == __last1
       || std::invoke(__comp, std::invoke(__proj1, *__first1), std::invoke(__proj2, *__first2)))
        return true;
      if (std::invoke(__comp, std::invoke(__proj2, *__first2), std::invoke(__proj1, *__first1)))
        return false;
      ++__first1;
      ++__first2;
    }
    return false;
  }

  template <input_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
            input_iterator _Iter2, sentinel_for<_Iter2> _Sent2,
            class _Proj1 = identity,
            class _Proj2 = identity,
            indirect_strict_weak_order<projected<_Iter1, _Proj1>, projected<_Iter2, _Proj2>> _Comp = ranges::less>
  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr
  bool operator()(_Iter1 __first1, _Sent1 __last1,
                  _Iter2 __first2, _Sent2 __last2,
                  _Comp __comp = {},
                  _Proj1 __proj1 = {},
                  _Proj2 __proj2 = {}) const {
    return __lexicographical_compare_impl(std::move(__first1), std::move(__last1),
                                          std::move(__first2), std::move(__last2),
                                          __comp,
                                          __proj1,
                                          __proj2);
  }

  template <input_range _Range1,
            input_range _Range2,
            class _Proj1 = identity,
            class _Proj2 = identity,
            indirect_strict_weak_order<projected<iterator_t<_Range1>, _Proj1>,
                                       projected<iterator_t<_Range2>, _Proj2>> _Comp = ranges::less>
  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr
  bool operator()(_Range1&& __range1, _Range2&& __range2, _Comp __comp = {}, _Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const {
    return __lexicographical_compare_impl(ranges::begin(__range1), ranges::end(__range1),
                                          ranges::begin(__range2), ranges::end(__range2),
                                          __comp,
                                          __proj1,
                                          __proj2);
  }

};
} // namespace __lexicographical_compare

inline namespace __cpo {
  inline constexpr auto lexicographical_compare = __lexicographical_compare::__fn{};
} // namespace __cpo
} // namespace ranges

_LIBCPP_END_NAMESPACE_STD

#endif // _LIBCPP_STD_VER > 17

#endif // _LIBCPP___ALGORITHM_RANGES_LEXICOGRAPHICAL_COMPARE_H