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The C and C++ Include Header Files

/usr/include/c++/11/bits/ranges_cmp.h

$ cat -n /usr/include/c++/11/bits/ranges_cmp.h

     1	// Concept-constrained comparison implementations -*- C++ -*-
     2	
     3	// Copyright (C) 2019-2021 Free Software Foundation, Inc.
     4	//
     5	// This file is part of the GNU ISO C++ Library.  This library is free
     6	// software; you can redistribute it and/or modify it under the
     7	// terms of the GNU General Public License as published by the
     8	// Free Software Foundation; either version 3, or (at your option)
     9	// any later version.
    10	
    11	// This library is distributed in the hope that it will be useful,
    12	// but WITHOUT ANY WARRANTY; without even the implied warranty of
    13	// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    14	// GNU General Public License for more details.
    15	
    16	// Under Section 7 of GPL version 3, you are granted additional
    17	// permissions described in the GCC Runtime Library Exception, version
    18	// 3.1, as published by the Free Software Foundation.
    19	
    20	// You should have received a copy of the GNU General Public License and
    21	// a copy of the GCC Runtime Library Exception along with this program;
    22	// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
    23	// <http://www.gnu.org/licenses/>.
    24	
    25	/** @file bits/ranges_cmp.h
    26	 *  This is an internal header file, included by other library headers.
    27	 *  Do not attempt to use it directly. @headername{functional}
    28	 */
    29	
    30	#ifndef _RANGES_CMP_H
    31	#define _RANGES_CMP_H 1
    32	
    33	#if __cplusplus > 201703L
    34	# include <bits/move.h>
    35	# include <concepts>
    36	
    37	namespace std _GLIBCXX_VISIBILITY(default)
    38	{
    39	_GLIBCXX_BEGIN_NAMESPACE_VERSION
    40	
    41	  struct __is_transparent; // not defined
    42	
    43	  // Define std::identity here so that <iterator> and <ranges>
    44	  // don't need to include <bits/stl_function.h> to get it.
    45	
    46	  /// [func.identity] The identity function.
    47	  struct identity
    48	  {
    49	    template<typename _Tp>
    50	      [[nodiscard]]
    51	      constexpr _Tp&&
    52	      operator()(_Tp&& __t) const noexcept
    53	      { return std::forward<_Tp>(__t); }
    54	
    55	    using is_transparent = __is_transparent;
    56	  };
    57	
    58	#ifdef __cpp_lib_concepts
    59	// Define this here, included by all the headers that need to define it.
    60	#define __cpp_lib_ranges 202106L
    61	
    62	namespace ranges
    63	{
    64	  namespace __detail
    65	  {
    66	    // BUILTIN-PTR-CMP(T, <, U)
    67	    // This determines whether t < u results in a call to a built-in operator<
    68	    // comparing pointers. It doesn't work for function pointers (PR 93628).
    69	    template<typename _Tp, typename _Up>
    70	      concept __less_builtin_ptr_cmp
    71		= requires (_Tp&& __t, _Up&& __u) { { __t < __u } -> same_as<bool>; }
    72		  && convertible_to<_Tp, const volatile void*>
    73		  && convertible_to<_Up, const volatile void*>
    74		  && (! requires(_Tp&& __t, _Up&& __u)
    75		      { operator<(std::forward<_Tp>(__t), std::forward<_Up>(__u)); }
    76		      && ! requires(_Tp&& __t, _Up&& __u)
    77		      { std::forward<_Tp>(__t).operator<(std::forward<_Up>(__u)); });
    78	  } // namespace __detail
    79	
    80	  // [range.cmp] Concept-constrained comparisons
    81	
    82	  // _GLIBCXX_RESOLVE_LIB_DEFECTS
    83	  // 3530 BUILTIN-PTR-MEOW should not opt the type out of syntactic checks
    84	
    85	  /// ranges::equal_to function object type.
    86	  struct equal_to
    87	  {
    88	    template<typename _Tp, typename _Up>
    89	      requires equality_comparable_with<_Tp, _Up>
    90	      constexpr bool
    91	      operator()(_Tp&& __t, _Up&& __u) const
    92	      noexcept(noexcept(std::declval<_Tp>() == std::declval<_Up>()))
    93	      { return std::forward<_Tp>(__t) == std::forward<_Up>(__u); }
    94	
    95	    using is_transparent = __is_transparent;
    96	  };
    97	
    98	  /// ranges::not_equal_to function object type.
    99	  struct not_equal_to
   100	  {
   101	    template<typename _Tp, typename _Up>
   102	      requires equality_comparable_with<_Tp, _Up>
   103	      constexpr bool
   104	      operator()(_Tp&& __t, _Up&& __u) const
   105	      noexcept(noexcept(std::declval<_Up>() == std::declval<_Tp>()))
   106	      { return !equal_to{}(std::forward<_Tp>(__t), std::forward<_Up>(__u)); }
   107	
   108	    using is_transparent = __is_transparent;
   109	  };
   110	
   111	  /// ranges::less function object type.
   112	  struct less
   113	  {
   114	    template<typename _Tp, typename _Up>
   115	      requires totally_ordered_with<_Tp, _Up>
   116	      constexpr bool
   117	      operator()(_Tp&& __t, _Up&& __u) const
   118	      noexcept(noexcept(std::declval<_Tp>() < std::declval<_Up>()))
   119	      {
   120		if constexpr (__detail::__less_builtin_ptr_cmp<_Tp, _Up>)
   121		  {
   122	#ifdef __cpp_lib_is_constant_evaluated
   123		    if (std::is_constant_evaluated())
   124		      return __t < __u;
   125	#endif
   126		    auto __x = reinterpret_cast<__UINTPTR_TYPE__>(
   127		      static_cast<const volatile void*>(std::forward<_Tp>(__t)));
   128		    auto __y = reinterpret_cast<__UINTPTR_TYPE__>(
   129		      static_cast<const volatile void*>(std::forward<_Up>(__u)));
   130		    return __x < __y;
   131		  }
   132		else
   133		  return std::forward<_Tp>(__t) < std::forward<_Up>(__u);
   134	      }
   135	
   136	    using is_transparent = __is_transparent;
   137	  };
   138	
   139	  /// ranges::greater function object type.
   140	  struct greater
   141	  {
   142	    template<typename _Tp, typename _Up>
   143	      requires totally_ordered_with<_Tp, _Up>
   144	      constexpr bool
   145	      operator()(_Tp&& __t, _Up&& __u) const
   146	      noexcept(noexcept(std::declval<_Up>() < std::declval<_Tp>()))
   147	      { return less{}(std::forward<_Up>(__u), std::forward<_Tp>(__t)); }
   148	
   149	    using is_transparent = __is_transparent;
   150	  };
   151	
   152	  /// ranges::greater_equal function object type.
   153	  struct greater_equal
   154	  {
   155	    template<typename _Tp, typename _Up>
   156	      requires totally_ordered_with<_Tp, _Up>
   157	      constexpr bool
   158	      operator()(_Tp&& __t, _Up&& __u) const
   159	      noexcept(noexcept(std::declval<_Tp>() < std::declval<_Up>()))
   160	      { return !less{}(std::forward<_Tp>(__t), std::forward<_Up>(__u)); }
   161	
   162	    using is_transparent = __is_transparent;
   163	  };
   164	
   165	  /// ranges::less_equal function object type.
   166	  struct less_equal
   167	  {
   168	    template<typename _Tp, typename _Up>
   169	      requires totally_ordered_with<_Tp, _Up>
   170	      constexpr bool
   171	      operator()(_Tp&& __t, _Up&& __u) const
   172	      noexcept(noexcept(std::declval<_Up>() < std::declval<_Tp>()))
   173	      { return !less{}(std::forward<_Up>(__u), std::forward<_Tp>(__t)); }
   174	
   175	    using is_transparent = __is_transparent;
   176	  };
   177	
   178	} // namespace ranges
   179	#endif // library concepts
   180	_GLIBCXX_END_NAMESPACE_VERSION
   181	} // namespace std
   182	#endif // C++20
   183	#endif // _RANGES_CMP_H
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