libstdc++
utility
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00001 // <utility> -*- C++ -*-
00002 
00003 // Copyright (C) 2001-2016 Free Software Foundation, Inc.
00004 //
00005 // This file is part of the GNU ISO C++ Library.  This library is free
00006 // software; you can redistribute it and/or modify it under the
00007 // terms of the GNU General Public License as published by the
00008 // Free Software Foundation; either version 3, or (at your option)
00009 // any later version.
00010 
00011 // This library is distributed in the hope that it will be useful,
00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00014 // GNU General Public License for more details.
00015 
00016 // Under Section 7 of GPL version 3, you are granted additional
00017 // permissions described in the GCC Runtime Library Exception, version
00018 // 3.1, as published by the Free Software Foundation.
00019 
00020 // You should have received a copy of the GNU General Public License and
00021 // a copy of the GCC Runtime Library Exception along with this program;
00022 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
00023 // <http://www.gnu.org/licenses/>.
00024 
00025 /*
00026  *
00027  * Copyright (c) 1994
00028  * Hewlett-Packard Company
00029  *
00030  * Permission to use, copy, modify, distribute and sell this software
00031  * and its documentation for any purpose is hereby granted without fee,
00032  * provided that the above copyright notice appear in all copies and
00033  * that both that copyright notice and this permission notice appear
00034  * in supporting documentation.  Hewlett-Packard Company makes no
00035  * representations about the suitability of this software for any
00036  * purpose.  It is provided "as is" without express or implied warranty.
00037  *
00038  *
00039  * Copyright (c) 1996,1997
00040  * Silicon Graphics Computer Systems, Inc.
00041  *
00042  * Permission to use, copy, modify, distribute and sell this software
00043  * and its documentation for any purpose is hereby granted without fee,
00044  * provided that the above copyright notice appear in all copies and
00045  * that both that copyright notice and this permission notice appear
00046  * in supporting documentation.  Silicon Graphics makes no
00047  * representations about the suitability of this software for any
00048  * purpose.  It is provided "as is" without express or implied warranty.
00049  */
00050 
00051 /** @file include/utility
00052  *  This is a Standard C++ Library header. 
00053  */
00054 
00055 #ifndef _GLIBCXX_UTILITY
00056 #define _GLIBCXX_UTILITY 1
00057 
00058 #pragma GCC system_header
00059 
00060 /**
00061  * @defgroup utilities Utilities
00062  *
00063  * Components deemed generally useful. Includes pair, tuple,
00064  * forward/move helpers, ratio, function object, metaprogramming and
00065  * type traits, time, date, and memory functions.
00066  */
00067 
00068 #include <bits/c++config.h>
00069 #include <bits/stl_relops.h>
00070 #include <bits/stl_pair.h>
00071 
00072 #if __cplusplus >= 201103L
00073 
00074 #include <type_traits>
00075 #include <bits/move.h>
00076 #include <initializer_list>
00077 
00078 namespace std _GLIBCXX_VISIBILITY(default)
00079 {
00080 _GLIBCXX_BEGIN_NAMESPACE_VERSION
00081 
00082   /// Finds the size of a given tuple type.
00083   template<typename _Tp>
00084     struct tuple_size;
00085 
00086   // _GLIBCXX_RESOLVE_LIB_DEFECTS
00087   // 2313. tuple_size should always derive from integral_constant<size_t, N>
00088   template<typename _Tp>
00089     struct tuple_size<const _Tp>
00090     : integral_constant<size_t, tuple_size<_Tp>::value> { };
00091 
00092   template<typename _Tp>
00093     struct tuple_size<volatile _Tp>
00094     : integral_constant<size_t, tuple_size<_Tp>::value> { };
00095 
00096   template<typename _Tp>
00097     struct tuple_size<const volatile _Tp>
00098     : integral_constant<size_t, tuple_size<_Tp>::value> { };
00099 
00100   /// Gives the type of the ith element of a given tuple type.
00101   template<std::size_t __i, typename _Tp>
00102     struct tuple_element;
00103 
00104   // Duplicate of C++14's tuple_element_t for internal use in C++11 mode
00105   template<std::size_t __i, typename _Tp>
00106     using __tuple_element_t = typename tuple_element<__i, _Tp>::type;
00107 
00108   template<std::size_t __i, typename _Tp>
00109     struct tuple_element<__i, const _Tp>
00110     {
00111       typedef typename add_const<__tuple_element_t<__i, _Tp>>::type type;
00112     };
00113 
00114   template<std::size_t __i, typename _Tp>
00115     struct tuple_element<__i, volatile _Tp>
00116     {
00117       typedef typename add_volatile<__tuple_element_t<__i, _Tp>>::type type;
00118     };
00119 
00120   template<std::size_t __i, typename _Tp>
00121     struct tuple_element<__i, const volatile _Tp>
00122     {
00123       typedef typename add_cv<__tuple_element_t<__i, _Tp>>::type type;
00124     };
00125 
00126 #if __cplusplus > 201103L
00127 #define __cpp_lib_tuple_element_t 201402
00128 
00129   template<std::size_t __i, typename _Tp>
00130     using tuple_element_t = typename tuple_element<__i, _Tp>::type;
00131 #endif
00132 
00133   template<typename>
00134     struct __is_tuple_like_impl : false_type
00135     { };
00136 
00137   // Various functions which give std::pair a tuple-like interface.
00138 
00139   /// Partial specialization for std::pair
00140   template<typename _T1, typename _T2>
00141     struct __is_tuple_like_impl<std::pair<_T1, _T2>> : true_type
00142     { };
00143 
00144   /// Partial specialization for std::pair
00145   template<class _Tp1, class _Tp2>
00146     struct tuple_size<std::pair<_Tp1, _Tp2>>
00147     : public integral_constant<std::size_t, 2> { };
00148 
00149   /// Partial specialization for std::pair
00150   template<class _Tp1, class _Tp2>
00151     struct tuple_element<0, std::pair<_Tp1, _Tp2>>
00152     { typedef _Tp1 type; };
00153  
00154   /// Partial specialization for std::pair
00155   template<class _Tp1, class _Tp2>
00156     struct tuple_element<1, std::pair<_Tp1, _Tp2>>
00157     { typedef _Tp2 type; };
00158 
00159   template<std::size_t _Int>
00160     struct __pair_get;
00161 
00162   template<>
00163     struct __pair_get<0>
00164     {
00165       template<typename _Tp1, typename _Tp2>
00166         static constexpr _Tp1&
00167         __get(std::pair<_Tp1, _Tp2>& __pair) noexcept
00168         { return __pair.first; }
00169 
00170       template<typename _Tp1, typename _Tp2>
00171         static constexpr _Tp1&&
00172         __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
00173         { return std::forward<_Tp1>(__pair.first); }
00174 
00175       template<typename _Tp1, typename _Tp2>
00176         static constexpr const _Tp1&
00177         __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept
00178         { return __pair.first; }
00179     };
00180 
00181   template<>
00182     struct __pair_get<1>
00183     {
00184       template<typename _Tp1, typename _Tp2>
00185         static constexpr _Tp2&
00186         __get(std::pair<_Tp1, _Tp2>& __pair) noexcept
00187         { return __pair.second; }
00188 
00189       template<typename _Tp1, typename _Tp2>
00190         static constexpr _Tp2&&
00191         __move_get(std::pair<_Tp1, _Tp2>&& __pair) noexcept
00192         { return std::forward<_Tp2>(__pair.second); }
00193 
00194       template<typename _Tp1, typename _Tp2>
00195         static constexpr const _Tp2&
00196         __const_get(const std::pair<_Tp1, _Tp2>& __pair) noexcept
00197         { return __pair.second; }
00198     };
00199 
00200   template<std::size_t _Int, class _Tp1, class _Tp2>
00201     constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&
00202     get(std::pair<_Tp1, _Tp2>& __in) noexcept
00203     { return __pair_get<_Int>::__get(__in); }
00204 
00205   template<std::size_t _Int, class _Tp1, class _Tp2>
00206     constexpr typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&&
00207     get(std::pair<_Tp1, _Tp2>&& __in) noexcept
00208     { return __pair_get<_Int>::__move_get(std::move(__in)); }
00209 
00210   template<std::size_t _Int, class _Tp1, class _Tp2>
00211     constexpr const typename tuple_element<_Int, std::pair<_Tp1, _Tp2>>::type&
00212     get(const std::pair<_Tp1, _Tp2>& __in) noexcept
00213     { return __pair_get<_Int>::__const_get(__in); }
00214 
00215 #if __cplusplus > 201103L
00216 
00217 #define __cpp_lib_tuples_by_type 201304
00218 
00219   template <typename _Tp, typename _Up>
00220     constexpr _Tp&
00221     get(pair<_Tp, _Up>& __p) noexcept
00222     { return __p.first; }
00223 
00224   template <typename _Tp, typename _Up>
00225     constexpr const _Tp&
00226     get(const pair<_Tp, _Up>& __p) noexcept
00227     { return __p.first; }
00228 
00229   template <typename _Tp, typename _Up>
00230     constexpr _Tp&&
00231     get(pair<_Tp, _Up>&& __p) noexcept
00232     { return std::move(__p.first); }
00233 
00234   template <typename _Tp, typename _Up>
00235     constexpr _Tp&
00236     get(pair<_Up, _Tp>& __p) noexcept
00237     { return __p.second; }
00238 
00239   template <typename _Tp, typename _Up>
00240     constexpr const _Tp&
00241     get(const pair<_Up, _Tp>& __p) noexcept
00242     { return __p.second; }
00243 
00244   template <typename _Tp, typename _Up>
00245     constexpr _Tp&&
00246     get(pair<_Up, _Tp>&& __p) noexcept
00247     { return std::move(__p.second); }
00248 
00249 #define __cpp_lib_exchange_function 201304
00250 
00251   /// Assign @p __new_val to @p __obj and return its previous value.
00252   template <typename _Tp, typename _Up = _Tp>
00253     inline _Tp
00254     exchange(_Tp& __obj, _Up&& __new_val)
00255     { return std::__exchange(__obj, std::forward<_Up>(__new_val)); }
00256 #endif
00257 
00258   // Stores a tuple of indices.  Used by tuple and pair, and by bind() to
00259   // extract the elements in a tuple.
00260   template<size_t... _Indexes> struct _Index_tuple { };
00261 
00262   // Concatenates two _Index_tuples.
00263   template<typename _Itup1, typename _Itup2> struct _Itup_cat;
00264 
00265   template<size_t... _Ind1, size_t... _Ind2>
00266     struct _Itup_cat<_Index_tuple<_Ind1...>, _Index_tuple<_Ind2...>>
00267     {
00268       using __type = _Index_tuple<_Ind1..., (_Ind2 + sizeof...(_Ind1))...>;
00269     };
00270 
00271   // Builds an _Index_tuple<0, 1, 2, ..., _Num-1>.
00272   template<size_t _Num>
00273     struct _Build_index_tuple
00274     : _Itup_cat<typename _Build_index_tuple<_Num / 2>::__type,
00275                 typename _Build_index_tuple<_Num - _Num / 2>::__type>
00276     { };
00277 
00278   template<>
00279     struct _Build_index_tuple<1>
00280     {
00281       typedef _Index_tuple<0> __type;
00282     };
00283 
00284   template<>
00285     struct _Build_index_tuple<0>
00286     {
00287       typedef _Index_tuple<> __type;
00288     };
00289 
00290 #if __cplusplus > 201103L
00291 
00292 #define __cpp_lib_integer_sequence 201304
00293 
00294   /// Class template integer_sequence
00295   template<typename _Tp, _Tp... _Idx>
00296     struct integer_sequence
00297     {
00298       typedef _Tp value_type;
00299       static constexpr size_t size() { return sizeof...(_Idx); }
00300     };
00301 
00302   template<typename _Tp, _Tp _Num,
00303            typename _ISeq = typename _Build_index_tuple<_Num>::__type>
00304     struct _Make_integer_sequence;
00305 
00306   template<typename _Tp, _Tp _Num,  size_t... _Idx>
00307     struct _Make_integer_sequence<_Tp, _Num, _Index_tuple<_Idx...>>
00308     {
00309       static_assert( _Num >= 0,
00310                      "Cannot make integer sequence of negative length" );
00311 
00312       typedef integer_sequence<_Tp, static_cast<_Tp>(_Idx)...> __type;
00313     };
00314 
00315   /// Alias template make_integer_sequence
00316   template<typename _Tp, _Tp _Num>
00317     using make_integer_sequence
00318       = typename _Make_integer_sequence<_Tp, _Num>::__type;
00319 
00320   /// Alias template index_sequence
00321   template<size_t... _Idx>
00322     using index_sequence = integer_sequence<size_t, _Idx...>;
00323 
00324   /// Alias template make_index_sequence
00325   template<size_t _Num>
00326     using make_index_sequence = make_integer_sequence<size_t, _Num>;
00327 
00328   /// Alias template index_sequence_for
00329   template<typename... _Types>
00330     using index_sequence_for = make_index_sequence<sizeof...(_Types)>;
00331 #endif
00332 
00333 _GLIBCXX_END_NAMESPACE_VERSION
00334 } // namespace
00335 
00336 #endif
00337 
00338 #endif /* _GLIBCXX_UTILITY */