libcxx/include/__algorithm/ranges_generate.h

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef _LIBCPP___ALGORITHM_RANGES_GENERATE_H
  10 #define _LIBCPP___ALGORITHM_RANGES_GENERATE_H
  11
  12 #include <__concepts/constructible.h>
  13 #include <__concepts/invocable.h>
  14 #include <__config>
  15 #include <__iterator/concepts.h>
  16 #include <__iterator/iterator_traits.h>
  17 #include <__ranges/access.h>
  18 #include <__ranges/concepts.h>
  19 #include <__ranges/dangling.h>
  20 #include <__type_traits/invoke.h>
  21 #include <__utility/move.h>
  22
  23 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  24 #  pragma GCC system_header
  25 #endif
  26
  27 _LIBCPP_PUSH_MACROS
  28 #include <__undef_macros>
  29
  30 #if _LIBCPP_STD_VER >= 20
  31
  32 _LIBCPP_BEGIN_NAMESPACE_STD
  33
  34 namespace ranges {
  35 struct __generate {
  36   template <class _OutIter, class _Sent, class _Func>
  37   _LIBCPP_HIDE_FROM_ABI constexpr static _OutIter __generate_fn_impl(_OutIter __first, _Sent __last, _Func& __gen) {
  38     for (; __first != __last; ++__first) {
  39       *__first = __gen();
  40     }
  41
  42     return __first;
  43   }
  44
  45   template <input_or_output_iterator _OutIter, sentinel_for<_OutIter> _Sent, copy_constructible _Func>
  46     requires invocable<_Func&> && indirectly_writable<_OutIter, invoke_result_t<_Func&>>
  47   _LIBCPP_HIDE_FROM_ABI constexpr _OutIter operator()(_OutIter __first, _Sent __last, _Func __gen) const {
  48     return __generate_fn_impl(std::move(__first), std::move(__last), __gen);
  49   }
  50
  51   template <class _Range, copy_constructible _Func>
  52     requires invocable<_Func&> && output_range<_Range, invoke_result_t<_Func&>>
  53   _LIBCPP_HIDE_FROM_ABI constexpr borrowed_iterator_t<_Range> operator()(_Range&& __range, _Func __gen) const {
  54     return __generate_fn_impl(ranges::begin(__range), ranges::end(__range), __gen);
  55   }
  56 };
  57
  58 inline namespace __cpo {
  59 inline constexpr auto generate = __generate{};
  60 } // namespace __cpo
  61 } // namespace ranges
  62
  63 _LIBCPP_END_NAMESPACE_STD
  64
  65 #endif // _LIBCPP_STD_VER >= 20
  66
  67 _LIBCPP_POP_MACROS
  68
  69 #endif // _LIBCPP___ALGORITHM_RANGES_GENERATE_H