utility

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// <utility> -*- C++ -*-
 
// Copyright (C) 2001-2021 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
 
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
 
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
 
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.
 
/*
 *
 * Copyright (c) 1994
 * Hewlett-Packard Company
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Hewlett-Packard Company makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 *
 *
 * Copyright (c) 1996,1997
 * Silicon Graphics Computer Systems, Inc.
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Silicon Graphics makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 */
 
/** @file include/utility
 *  This is a Standard C++ Library header.
 */
 
#ifndef _GLIBCXX_UTILITY
#define _GLIBCXX_UTILITY 1
 
#pragma GCC system_header
 
/**
 * @defgroup utilities Utilities
 *
 * Components deemed generally useful. Includes pair, tuple,
 * forward/move helpers, ratio, function object, metaprogramming and
 * type traits, time, date, and memory functions.
 */
 
#include <bits/c++config.h>
#include <bits/stl_relops.h>
#include <bits/stl_pair.h>
 
#if __cplusplus >= 201103L
 
#include <type_traits>
#include <bits/move.h>
#include <initializer_list>
 
#if __cplusplus > 201703L
#include <ext/numeric_traits.h>
#endif
 
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
 
  /// Finds the size of a given tuple type.
  template<typename _Tp>
    struct tuple_size;
 
  // _GLIBCXX_RESOLVE_LIB_DEFECTS
  // 2313. tuple_size should always derive from integral_constant<size_t, N>
  // 2770. tuple_size<const T> specialization is not SFINAE compatible
 
  template<typename _Tp,
           typename _Up = typename remove_cv<_Tp>::type,
           typename = typename enable_if<is_same<_Tp, _Up>::value>::type,
           size_t = tuple_size<_Tp>::value>
    using __enable_if_has_tuple_size = _Tp;
 
  template<typename _Tp>
    struct tuple_size<const __enable_if_has_tuple_size<_Tp>>
    : public tuple_size<_Tp> { };
 
  template<typename _Tp>
    struct tuple_size<volatile __enable_if_has_tuple_size<_Tp>>
    : public tuple_size<_Tp> { };
 
  template<typename _Tp>
    struct tuple_size<const volatile __enable_if_has_tuple_size<_Tp>>
    : public tuple_size<_Tp> { };
 
  /// Gives the type of the ith element of a given tuple type.
  template<size_t __i, typename _Tp>
    struct tuple_element;
 
  // Duplicate of C++14's tuple_element_t for internal use in C++11 mode
  template<size_t __i, typename _Tp>
    using __tuple_element_t = typename tuple_element<__i, _Tp>::type;
 
  template<size_t __i, typename _Tp>
    struct tuple_element<__i, const _Tp>
    {
      typedef typename add_const<__tuple_element_t<__i, _Tp>>::type type;
    };
 
  template<size_t __i, typename _Tp>
    struct tuple_element<__i, volatile _Tp>
    {
      typedef typename add_volatile<__tuple_element_t<__i, _Tp>>::type type;
    };
 
  template<size_t __i, typename _Tp>
    struct tuple_element<__i, const volatile _Tp>
    {
      typedef typename add_cv<__tuple_element_t<__i, _Tp>>::type type;
    };
 
#if __cplusplus >= 201402L
// The standard says this macro and alias template should be in <tuple>
// but we define them here, to be available when the partial specializations
// of tuple_element<pair<T,U>> and tuple_element<array<T,N>> are defined.
#define __cpp_lib_tuple_element_t 201402L
 
  template<size_t __i, typename _Tp>
    using tuple_element_t = typename tuple_element<__i, _Tp>::type;
#endif
 
  // Various functions which give std::pair a tuple-like interface.
 
  /// Partial specialization for std::pair
  template<typename _T1, typename _T2>
    struct __is_tuple_like_impl<pair<_T1, _T2>> : true_type
    { };
 
  /// Partial specialization for std::pair
  template<class _Tp1, class _Tp2>
    struct tuple_size<pair<_Tp1, _Tp2>>
    : public integral_constant<size_t, 2> { };
 
  /// Partial specialization for std::pair
  template<class _Tp1, class _Tp2>
    struct tuple_element<0, pair<_Tp1, _Tp2>>
    { typedef _Tp1 type; };
 
  /// Partial specialization for std::pair
  template<class _Tp1, class _Tp2>
    struct tuple_element<1, pair<_Tp1, _Tp2>>
    { typedef _Tp2 type; };
 
  template<size_t _Int>
    struct __pair_get;
 
  template<>
    struct __pair_get<0>
    {
      template<typename _Tp1, typename _Tp2>
        static constexpr _Tp1&
        __get(pair<_Tp1, _Tp2>& __pair) noexcept
        { return __pair.first; }
 
      template<typename _Tp1, typename _Tp2>
        static constexpr _Tp1&&
        __move_get(pair<_Tp1, _Tp2>&& __pair) noexcept
        { return std::forward<_Tp1>(__pair.first); }
 
      template<typename _Tp1, typename _Tp2>
        static constexpr const _Tp1&
        __const_get(const pair<_Tp1, _Tp2>& __pair) noexcept
        { return __pair.first; }
 
      template<typename _Tp1, typename _Tp2>
        static constexpr const _Tp1&&
        __const_move_get(const pair<_Tp1, _Tp2>&& __pair) noexcept
        { return std::forward<const _Tp1>(__pair.first); }
    };
 
  template<>
    struct __pair_get<1>
    {
      template<typename _Tp1, typename _Tp2>
        static constexpr _Tp2&
        __get(pair<_Tp1, _Tp2>& __pair) noexcept
        { return __pair.second; }
 
      template<typename _Tp1, typename _Tp2>
        static constexpr _Tp2&&
        __move_get(pair<_Tp1, _Tp2>&& __pair) noexcept
        { return std::forward<_Tp2>(__pair.second); }
 
      template<typename _Tp1, typename _Tp2>
        static constexpr const _Tp2&
        __const_get(const pair<_Tp1, _Tp2>& __pair) noexcept
        { return __pair.second; }
 
      template<typename _Tp1, typename _Tp2>
        static constexpr const _Tp2&&
        __const_move_get(const pair<_Tp1, _Tp2>&& __pair) noexcept
        { return std::forward<const _Tp2>(__pair.second); }
    };
 
  template<size_t _Int, class _Tp1, class _Tp2>
    constexpr typename tuple_element<_Int, pair<_Tp1, _Tp2>>::type&
    get(pair<_Tp1, _Tp2>& __in) noexcept
    { return __pair_get<_Int>::__get(__in); }
 
  template<size_t _Int, class _Tp1, class _Tp2>
    constexpr typename tuple_element<_Int, pair<_Tp1, _Tp2>>::type&&
    get(pair<_Tp1, _Tp2>&& __in) noexcept
    { return __pair_get<_Int>::__move_get(std::move(__in)); }
 
  template<size_t _Int, class _Tp1, class _Tp2>
    constexpr const typename tuple_element<_Int, pair<_Tp1, _Tp2>>::type&
    get(const pair<_Tp1, _Tp2>& __in) noexcept
    { return __pair_get<_Int>::__const_get(__in); }
 
  template<size_t _Int, class _Tp1, class _Tp2>
    constexpr const typename tuple_element<_Int, pair<_Tp1, _Tp2>>::type&&
    get(const pair<_Tp1, _Tp2>&& __in) noexcept
    { return __pair_get<_Int>::__const_move_get(std::move(__in)); }
 
#if __cplusplus >= 201402L
 
#define __cpp_lib_tuples_by_type 201304
 
  template <typename _Tp, typename _Up>
    constexpr _Tp&
    get(pair<_Tp, _Up>& __p) noexcept
    { return __p.first; }
 
  template <typename _Tp, typename _Up>
    constexpr const _Tp&
    get(const pair<_Tp, _Up>& __p) noexcept
    { return __p.first; }
 
  template <typename _Tp, typename _Up>
    constexpr _Tp&&
    get(pair<_Tp, _Up>&& __p) noexcept
    { return std::move(__p.first); }
 
  template <typename _Tp, typename _Up>
    constexpr const _Tp&&
    get(const pair<_Tp, _Up>&& __p) noexcept
    { return std::move(__p.first); }
 
  template <typename _Tp, typename _Up>
    constexpr _Tp&
    get(pair<_Up, _Tp>& __p) noexcept
    { return __p.second; }
 
  template <typename _Tp, typename _Up>
    constexpr const _Tp&
    get(const pair<_Up, _Tp>& __p) noexcept
    { return __p.second; }
 
  template <typename _Tp, typename _Up>
    constexpr _Tp&&
    get(pair<_Up, _Tp>&& __p) noexcept
    { return std::move(__p.second); }
 
  template <typename _Tp, typename _Up>
    constexpr const _Tp&&
    get(const pair<_Up, _Tp>&& __p) noexcept
    { return std::move(__p.second); }
 
#define __cpp_lib_exchange_function 201304
 
  /// Assign @p __new_val to @p __obj and return its previous value.
  template <typename _Tp, typename _Up = _Tp>
    _GLIBCXX20_CONSTEXPR
    inline _Tp
    exchange(_Tp& __obj, _Up&& __new_val)
    { return std::__exchange(__obj, std::forward<_Up>(__new_val)); }
 
#endif // C++14
 
  // Stores a tuple of indices.  Used by tuple and pair, and by bind() to
  // extract the elements in a tuple.
  template<size_t... _Indexes> struct _Index_tuple { };
 
  // Builds an _Index_tuple<0, 1, 2, ..., _Num-1>.
  template<size_t _Num>
    struct _Build_index_tuple
    {
#if __has_builtin(__make_integer_seq)
      template<typename, size_t... _Indices>
        using _IdxTuple = _Index_tuple<_Indices...>;
 
      // Clang defines __make_integer_seq for this purpose.
      using __type = __make_integer_seq<_IdxTuple, size_t, _Num>;
#else
      // For GCC and other compilers, use __integer_pack instead.
      using __type = _Index_tuple<__integer_pack(_Num)...>;
#endif
    };
 
#if __cplusplus >= 201402L
 
#define __cpp_lib_integer_sequence 201304
 
  /// Class template integer_sequence
  template<typename _Tp, _Tp... _Idx>
    struct integer_sequence
    {
      typedef _Tp value_type;
      static constexpr size_t size() noexcept { return sizeof...(_Idx); }
    };
 
  /// Alias template make_integer_sequence
  template<typename _Tp, _Tp _Num>
    using make_integer_sequence
#if __has_builtin(__make_integer_seq)
      = __make_integer_seq<integer_sequence, _Tp, _Num>;
#else
      = integer_sequence<_Tp, __integer_pack(_Num)...>;
#endif
 
  /// Alias template index_sequence
  template<size_t... _Idx>
    using index_sequence = integer_sequence<size_t, _Idx...>;
 
  /// Alias template make_index_sequence
  template<size_t _Num>
    using make_index_sequence = make_integer_sequence<size_t, _Num>;
 
  /// Alias template index_sequence_for
  template<typename... _Types>
    using index_sequence_for = make_index_sequence<sizeof...(_Types)>;
#endif
 
#if __cplusplus > 201402L
 
  struct in_place_t {
    explicit in_place_t() = default;
  };
 
  inline constexpr in_place_t in_place{};
 
  template<typename _Tp> struct in_place_type_t
  {
    explicit in_place_type_t() = default;
  };
 
  template<typename _Tp>
    inline constexpr in_place_type_t<_Tp> in_place_type{};
 
  template<size_t _Idx> struct in_place_index_t
  {
    explicit in_place_index_t() = default;
  };
 
  template<size_t _Idx>
    inline constexpr in_place_index_t<_Idx> in_place_index{};
 
  template<typename>
    inline constexpr bool __is_in_place_type_v = false;
 
  template<typename _Tp>
    inline constexpr bool __is_in_place_type_v<in_place_type_t<_Tp>> = true;
 
  template<typename _Tp>
    using __is_in_place_type = bool_constant<__is_in_place_type_v<_Tp>>;
 
#define  __cpp_lib_as_const 201510
  template<typename _Tp>
    [[nodiscard]]
    constexpr add_const_t<_Tp>&
    as_const(_Tp& __t) noexcept
    { return __t; }
 
  template<typename _Tp>
    void as_const(const _Tp&&) = delete;
 
#if __cplusplus > 201703L
#define __cpp_lib_integer_comparison_functions 202002L
 
  template<typename _Tp, typename _Up>
    constexpr bool
    cmp_equal(_Tp __t, _Up __u) noexcept
    {
      static_assert(__is_standard_integer<_Tp>::value);
      static_assert(__is_standard_integer<_Up>::value);
 
      if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>)
        return __t == __u;
      else if constexpr (is_signed_v<_Tp>)
        return __t >= 0 && make_unsigned_t<_Tp>(__t) == __u;
      else
        return __u >= 0 && __t == make_unsigned_t<_Up>(__u);
    }
 
  template<typename _Tp, typename _Up>
    constexpr bool
    cmp_not_equal(_Tp __t, _Up __u) noexcept
    { return !std::cmp_equal(__t, __u); }
 
  template<typename _Tp, typename _Up>
    constexpr bool
    cmp_less(_Tp __t, _Up __u) noexcept
    {
      static_assert(__is_standard_integer<_Tp>::value);
      static_assert(__is_standard_integer<_Up>::value);
 
      if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>)
        return __t < __u;
      else if constexpr (is_signed_v<_Tp>)
        return __t < 0 || make_unsigned_t<_Tp>(__t) < __u;
      else
        return __u >= 0 && __t < make_unsigned_t<_Up>(__u);
    }
 
  template<typename _Tp, typename _Up>
    constexpr bool
    cmp_greater(_Tp __t, _Up __u) noexcept
    { return std::cmp_less(__u, __t); }
 
  template<typename _Tp, typename _Up>
    constexpr bool
    cmp_less_equal(_Tp __t, _Up __u) noexcept
    { return !std::cmp_less(__u, __t); }
 
  template<typename _Tp, typename _Up>
    constexpr bool
    cmp_greater_equal(_Tp __t, _Up __u) noexcept
    { return !std::cmp_less(__t, __u); }
 
  template<typename _Up, typename _Tp>
    constexpr bool
    in_range(_Tp __t) noexcept
    {
      static_assert(__is_standard_integer<_Up>::value);
      static_assert(__is_standard_integer<_Tp>::value);
      using __gnu_cxx::__int_traits;
 
      if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>)
        return __int_traits<_Up>::__min <= __t
          && __t <= __int_traits<_Up>::__max;
      else if constexpr (is_signed_v<_Tp>)
        return __t >= 0
          && make_unsigned_t<_Tp>(__t) <= __int_traits<_Up>::__max;
      else
        return __t <= make_unsigned_t<_Up>(__int_traits<_Up>::__max);
    }
 
#if __cplusplus > 202002L
#define __cpp_lib_to_underlying 202102L
  /// Convert an object of enumeration type to its underlying type.
  template<typename _Tp>
    [[nodiscard]]
    constexpr underlying_type_t<_Tp>
    to_underlying(_Tp __value) noexcept
    { return static_cast<underlying_type_t<_Tp>>(__value); }
#endif // C++23
#endif // C++20
#endif // C++17
 
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
 
#endif
 
#endif /* _GLIBCXX_UTILITY */