libcxx/include/__algorithm/for_each_n.h

   1 // -*- C++ -*-
   2 //===----------------------------------------------------------------------===//
   3 //
   4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   5 // See https://llvm.org/LICENSE.txt for license information.
   6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #ifndef _LIBCPP___ALGORITHM_FOR_EACH_N_H
  11 #define _LIBCPP___ALGORITHM_FOR_EACH_N_H
  12
  13 #include <__config>
  14 #include <__utility/convert_to_integral.h>
  15
  16 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  17 #  pragma GCC system_header
  18 #endif
  19
  20 _LIBCPP_BEGIN_NAMESPACE_STD
  21
  22 #if _LIBCPP_STD_VER >= 17
  23
  24 template <class _InputIterator, class _Size, class _Function>
  25 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 _InputIterator for_each_n(_InputIterator __first,
  26                                                                                          _Size __orig_n,
  27                                                                                          _Function __f) {
  28   typedef decltype(_VSTD::__convert_to_integral(__orig_n)) _IntegralSize;
  29   _IntegralSize __n = __orig_n;
  30   while (__n > 0) {
  31     __f(*__first);
  32     ++__first;
  33     --__n;
  34   }
  35   return __first;
  36 }
  37
  38 #endif
  39
  40 _LIBCPP_END_NAMESPACE_STD
  41
  42 #endif // _LIBCPP___ALGORITHM_FOR_EACH_N_H