libstdc++
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00001 // class template tuple -*- C++ -*- 00002 00003 // Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 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 /** @file tr1/tuple 00026 * This is a TR1 C++ Library header. 00027 */ 00028 00029 // Chris Jefferson <chris@bubblescope.net> 00030 // Variadic Templates support by Douglas Gregor <doug.gregor@gmail.com> 00031 00032 #ifndef _GLIBCXX_TR1_TUPLE 00033 #define _GLIBCXX_TR1_TUPLE 1 00034 00035 #pragma GCC system_header 00036 00037 #include <utility> 00038 00039 namespace std 00040 { 00041 namespace tr1 00042 { 00043 // Adds a const reference to a non-reference type. 00044 template<typename _Tp> 00045 struct __add_c_ref 00046 { typedef const _Tp& type; }; 00047 00048 template<typename _Tp> 00049 struct __add_c_ref<_Tp&> 00050 { typedef _Tp& type; }; 00051 00052 // Adds a reference to a non-reference type. 00053 template<typename _Tp> 00054 struct __add_ref 00055 { typedef _Tp& type; }; 00056 00057 template<typename _Tp> 00058 struct __add_ref<_Tp&> 00059 { typedef _Tp& type; }; 00060 00061 /** 00062 * Contains the actual implementation of the @c tuple template, stored 00063 * as a recursive inheritance hierarchy from the first element (most 00064 * derived class) to the last (least derived class). The @c Idx 00065 * parameter gives the 0-based index of the element stored at this 00066 * point in the hierarchy; we use it to implement a constant-time 00067 * get() operation. 00068 */ 00069 template<int _Idx, typename... _Elements> 00070 struct _Tuple_impl; 00071 00072 /** 00073 * Zero-element tuple implementation. This is the basis case for the 00074 * inheritance recursion. 00075 */ 00076 template<int _Idx> 00077 struct _Tuple_impl<_Idx> { }; 00078 00079 /** 00080 * Recursive tuple implementation. Here we store the @c Head element 00081 * and derive from a @c Tuple_impl containing the remaining elements 00082 * (which contains the @c Tail). 00083 */ 00084 template<int _Idx, typename _Head, typename... _Tail> 00085 struct _Tuple_impl<_Idx, _Head, _Tail...> 00086 : public _Tuple_impl<_Idx + 1, _Tail...> 00087 { 00088 typedef _Tuple_impl<_Idx + 1, _Tail...> _Inherited; 00089 00090 _Head _M_head; 00091 00092 _Inherited& _M_tail() { return *this; } 00093 const _Inherited& _M_tail() const { return *this; } 00094 00095 _Tuple_impl() : _Inherited(), _M_head() { } 00096 00097 explicit 00098 _Tuple_impl(typename __add_c_ref<_Head>::type __head, 00099 typename __add_c_ref<_Tail>::type... __tail) 00100 : _Inherited(__tail...), _M_head(__head) { } 00101 00102 template<typename... _UElements> 00103 _Tuple_impl(const _Tuple_impl<_Idx, _UElements...>& __in) 00104 : _Inherited(__in._M_tail()), _M_head(__in._M_head) { } 00105 00106 _Tuple_impl(const _Tuple_impl& __in) 00107 : _Inherited(__in._M_tail()), _M_head(__in._M_head) { } 00108 00109 template<typename... _UElements> 00110 _Tuple_impl& 00111 operator=(const _Tuple_impl<_Idx, _UElements...>& __in) 00112 { 00113 _M_head = __in._M_head; 00114 _M_tail() = __in._M_tail(); 00115 return *this; 00116 } 00117 00118 _Tuple_impl& 00119 operator=(const _Tuple_impl& __in) 00120 { 00121 _M_head = __in._M_head; 00122 _M_tail() = __in._M_tail(); 00123 return *this; 00124 } 00125 }; 00126 00127 template<typename... _Elements> 00128 class tuple : public _Tuple_impl<0, _Elements...> 00129 { 00130 typedef _Tuple_impl<0, _Elements...> _Inherited; 00131 00132 public: 00133 tuple() : _Inherited() { } 00134 00135 explicit 00136 tuple(typename __add_c_ref<_Elements>::type... __elements) 00137 : _Inherited(__elements...) { } 00138 00139 template<typename... _UElements> 00140 tuple(const tuple<_UElements...>& __in) 00141 : _Inherited(__in) { } 00142 00143 tuple(const tuple& __in) 00144 : _Inherited(__in) { } 00145 00146 template<typename... _UElements> 00147 tuple& 00148 operator=(const tuple<_UElements...>& __in) 00149 { 00150 static_cast<_Inherited&>(*this) = __in; 00151 return *this; 00152 } 00153 00154 tuple& 00155 operator=(const tuple& __in) 00156 { 00157 static_cast<_Inherited&>(*this) = __in; 00158 return *this; 00159 } 00160 }; 00161 00162 template<> class tuple<> { }; 00163 00164 // 2-element tuple, with construction and assignment from a pair. 00165 template<typename _T1, typename _T2> 00166 class tuple<_T1, _T2> : public _Tuple_impl<0, _T1, _T2> 00167 { 00168 typedef _Tuple_impl<0, _T1, _T2> _Inherited; 00169 00170 public: 00171 tuple() : _Inherited() { } 00172 00173 explicit 00174 tuple(typename __add_c_ref<_T1>::type __a1, 00175 typename __add_c_ref<_T2>::type __a2) 00176 : _Inherited(__a1, __a2) { } 00177 00178 template<typename _U1, typename _U2> 00179 tuple(const tuple<_U1, _U2>& __in) 00180 : _Inherited(__in) { } 00181 00182 tuple(const tuple& __in) 00183 : _Inherited(__in) { } 00184 00185 template<typename _U1, typename _U2> 00186 tuple(const pair<_U1, _U2>& __in) 00187 : _Inherited(_Tuple_impl<0, 00188 typename __add_c_ref<_U1>::type, 00189 typename __add_c_ref<_U2>::type>(__in.first, 00190 __in.second)) 00191 { } 00192 00193 template<typename _U1, typename _U2> 00194 tuple& 00195 operator=(const tuple<_U1, _U2>& __in) 00196 { 00197 static_cast<_Inherited&>(*this) = __in; 00198 return *this; 00199 } 00200 00201 tuple& 00202 operator=(const tuple& __in) 00203 { 00204 static_cast<_Inherited&>(*this) = __in; 00205 return *this; 00206 } 00207 00208 template<typename _U1, typename _U2> 00209 tuple& 00210 operator=(const pair<_U1, _U2>& __in) 00211 { 00212 this->_M_head = __in.first; 00213 this->_M_tail()._M_head = __in.second; 00214 return *this; 00215 } 00216 }; 00217 00218 00219 /// Gives the type of the ith element of a given tuple type. 00220 template<int __i, typename _Tp> 00221 struct tuple_element; 00222 00223 /** 00224 * Recursive case for tuple_element: strip off the first element in 00225 * the tuple and retrieve the (i-1)th element of the remaining tuple. 00226 */ 00227 template<int __i, typename _Head, typename... _Tail> 00228 struct tuple_element<__i, tuple<_Head, _Tail...> > 00229 : tuple_element<__i - 1, tuple<_Tail...> > { }; 00230 00231 /** 00232 * Basis case for tuple_element: The first element is the one we're seeking. 00233 */ 00234 template<typename _Head, typename... _Tail> 00235 struct tuple_element<0, tuple<_Head, _Tail...> > 00236 { 00237 typedef _Head type; 00238 }; 00239 00240 /// Finds the size of a given tuple type. 00241 template<typename _Tp> 00242 struct tuple_size; 00243 00244 /// class tuple_size 00245 template<typename... _Elements> 00246 struct tuple_size<tuple<_Elements...> > 00247 { 00248 static const int value = sizeof...(_Elements); 00249 }; 00250 00251 template<typename... _Elements> 00252 const int tuple_size<tuple<_Elements...> >::value; 00253 00254 template<int __i, typename _Head, typename... _Tail> 00255 inline typename __add_ref<_Head>::type 00256 __get_helper(_Tuple_impl<__i, _Head, _Tail...>& __t) 00257 { 00258 return __t._M_head; 00259 } 00260 00261 template<int __i, typename _Head, typename... _Tail> 00262 inline typename __add_c_ref<_Head>::type 00263 __get_helper(const _Tuple_impl<__i, _Head, _Tail...>& __t) 00264 { 00265 return __t._M_head; 00266 } 00267 00268 // Return a reference (const reference) to the ith element of a tuple. 00269 // Any const or non-const ref elements are returned with their original type. 00270 template<int __i, typename... _Elements> 00271 inline typename __add_ref< 00272 typename tuple_element<__i, tuple<_Elements...> >::type 00273 >::type 00274 get(tuple<_Elements...>& __t) 00275 { 00276 return __get_helper<__i>(__t); 00277 } 00278 00279 template<int __i, typename... _Elements> 00280 inline typename __add_c_ref< 00281 typename tuple_element<__i, tuple<_Elements...> >::type 00282 >::type 00283 get(const tuple<_Elements...>& __t) 00284 { 00285 return __get_helper<__i>(__t); 00286 } 00287 00288 // This class helps construct the various comparison operations on tuples 00289 template<int __check_equal_size, int __i, int __j, 00290 typename _Tp, typename _Up> 00291 struct __tuple_compare; 00292 00293 template<int __i, int __j, typename _Tp, typename _Up> 00294 struct __tuple_compare<0, __i, __j, _Tp, _Up> 00295 { 00296 static bool __eq(const _Tp& __t, const _Up& __u) 00297 { 00298 return (get<__i>(__t) == get<__i>(__u) && 00299 __tuple_compare<0, __i+1, __j, _Tp, _Up>::__eq(__t, __u)); 00300 } 00301 00302 static bool __less(const _Tp& __t, const _Up& __u) 00303 { 00304 return ((get<__i>(__t) < get<__i>(__u)) 00305 || !(get<__i>(__u) < get<__i>(__t)) && 00306 __tuple_compare<0, __i+1, __j, _Tp, _Up>::__less(__t, __u)); 00307 } 00308 }; 00309 00310 template<int __i, typename _Tp, typename _Up> 00311 struct __tuple_compare<0, __i, __i, _Tp, _Up> 00312 { 00313 static bool __eq(const _Tp&, const _Up&) 00314 { return true; } 00315 00316 static bool __less(const _Tp&, const _Up&) 00317 { return false; } 00318 }; 00319 00320 template<typename... _TElements, typename... _UElements> 00321 bool 00322 operator==(const tuple<_TElements...>& __t, 00323 const tuple<_UElements...>& __u) 00324 { 00325 typedef tuple<_TElements...> _Tp; 00326 typedef tuple<_UElements...> _Up; 00327 return (__tuple_compare<tuple_size<_Tp>::value - tuple_size<_Up>::value, 00328 0, tuple_size<_Tp>::value, _Tp, _Up>::__eq(__t, __u)); 00329 } 00330 00331 template<typename... _TElements, typename... _UElements> 00332 bool 00333 operator<(const tuple<_TElements...>& __t, 00334 const tuple<_UElements...>& __u) 00335 { 00336 typedef tuple<_TElements...> _Tp; 00337 typedef tuple<_UElements...> _Up; 00338 return (__tuple_compare<tuple_size<_Tp>::value - tuple_size<_Up>::value, 00339 0, tuple_size<_Tp>::value, _Tp, _Up>::__less(__t, __u)); 00340 } 00341 00342 template<typename... _TElements, typename... _UElements> 00343 inline bool 00344 operator!=(const tuple<_TElements...>& __t, 00345 const tuple<_UElements...>& __u) 00346 { return !(__t == __u); } 00347 00348 template<typename... _TElements, typename... _UElements> 00349 inline bool 00350 operator>(const tuple<_TElements...>& __t, 00351 const tuple<_UElements...>& __u) 00352 { return __u < __t; } 00353 00354 template<typename... _TElements, typename... _UElements> 00355 inline bool 00356 operator<=(const tuple<_TElements...>& __t, 00357 const tuple<_UElements...>& __u) 00358 { return !(__u < __t); } 00359 00360 template<typename... _TElements, typename... _UElements> 00361 inline bool 00362 operator>=(const tuple<_TElements...>& __t, 00363 const tuple<_UElements...>& __u) 00364 { return !(__t < __u); } 00365 00366 template<typename _Tp> 00367 class reference_wrapper; 00368 00369 // Helper which adds a reference to a type when given a reference_wrapper 00370 template<typename _Tp> 00371 struct __strip_reference_wrapper 00372 { 00373 typedef _Tp __type; 00374 }; 00375 00376 template<typename _Tp> 00377 struct __strip_reference_wrapper<reference_wrapper<_Tp> > 00378 { 00379 typedef _Tp& __type; 00380 }; 00381 00382 template<typename _Tp> 00383 struct __strip_reference_wrapper<const reference_wrapper<_Tp> > 00384 { 00385 typedef _Tp& __type; 00386 }; 00387 00388 template<typename... _Elements> 00389 inline tuple<typename __strip_reference_wrapper<_Elements>::__type...> 00390 make_tuple(_Elements... __args) 00391 { 00392 typedef tuple<typename __strip_reference_wrapper<_Elements>::__type...> 00393 __result_type; 00394 return __result_type(__args...); 00395 } 00396 00397 template<typename... _Elements> 00398 inline tuple<_Elements&...> 00399 tie(_Elements&... __args) 00400 { 00401 return tuple<_Elements&...>(__args...); 00402 } 00403 00404 // A class (and instance) which can be used in 'tie' when an element 00405 // of a tuple is not required 00406 struct _Swallow_assign 00407 { 00408 template<class _Tp> 00409 _Swallow_assign& 00410 operator=(const _Tp&) 00411 { return *this; } 00412 }; 00413 00414 // TODO: Put this in some kind of shared file. 00415 namespace 00416 { 00417 _Swallow_assign ignore; 00418 }; // anonymous namespace 00419 } 00420 } 00421 00422 #endif // _GLIBCXX_TR1_TUPLE