libstdc++
bits/alloc_traits.h
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00001 // Allocator traits -*- C++ -*-
00002 
00003 // Copyright (C) 2011, 2012 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 bits/alloc_traits.h
00026  *  This is an internal header file, included by other library headers.
00027  *  Do not attempt to use it directly. @headername{memory}
00028  */
00029 
00030 #ifndef _ALLOC_TRAITS_H
00031 #define _ALLOC_TRAITS_H 1
00032 
00033 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00034 
00035 #include <bits/ptr_traits.h>
00036 #include <ext/numeric_traits.h>
00037 
00038 namespace std _GLIBCXX_VISIBILITY(default)
00039 {
00040 _GLIBCXX_BEGIN_NAMESPACE_VERSION
00041 
00042   template<typename _Alloc, typename _Tp>
00043     class __alloctr_rebind_helper
00044     {
00045       template<typename _Alloc2, typename _Tp2>
00046     static constexpr bool
00047         _S_chk(typename _Alloc2::template rebind<_Tp2>::other*)
00048     { return true; }
00049 
00050       template<typename, typename>
00051         static constexpr bool
00052         _S_chk(...)
00053         { return false; }
00054 
00055     public:
00056       static const bool __value = _S_chk<_Alloc, _Tp>(nullptr);
00057     };
00058 
00059   template<typename _Alloc, typename _Tp>
00060     const bool __alloctr_rebind_helper<_Alloc, _Tp>::__value;
00061 
00062   template<typename _Alloc, typename _Tp,
00063            bool = __alloctr_rebind_helper<_Alloc, _Tp>::__value>
00064     struct __alloctr_rebind;
00065 
00066   template<typename _Alloc, typename _Tp>
00067     struct __alloctr_rebind<_Alloc, _Tp, true>
00068     {
00069       typedef typename _Alloc::template rebind<_Tp>::other __type;
00070     };
00071 
00072   template<template<typename, typename...> class _Alloc, typename _Tp,
00073             typename _Up, typename... _Args>
00074     struct __alloctr_rebind<_Alloc<_Up, _Args...>, _Tp, false>
00075     {
00076       typedef _Alloc<_Tp, _Args...> __type;
00077     };
00078 
00079   /**
00080    * @brief  Uniform interface to all allocator types.
00081    * @ingroup allocators
00082   */
00083   template<typename _Alloc>
00084     struct allocator_traits
00085     {
00086       /// The allocator type
00087       typedef _Alloc allocator_type;
00088       /// The allocated type
00089       typedef typename _Alloc::value_type value_type;
00090 
00091 #define _GLIBCXX_ALLOC_TR_NESTED_TYPE(_NTYPE, _ALT) \
00092   private: \
00093   template<typename _Tp> \
00094     static typename _Tp::_NTYPE _S_##_NTYPE##_helper(_Tp*); \
00095   static _ALT _S_##_NTYPE##_helper(...); \
00096     typedef decltype(_S_##_NTYPE##_helper((_Alloc*)0)) __##_NTYPE; \
00097   public:
00098 
00099 _GLIBCXX_ALLOC_TR_NESTED_TYPE(pointer, value_type*)
00100 
00101       /**
00102        * @brief   The allocator's pointer type.
00103        *
00104        * @c Alloc::pointer if that type exists, otherwise @c value_type*
00105       */
00106       typedef __pointer pointer;
00107 
00108 _GLIBCXX_ALLOC_TR_NESTED_TYPE(const_pointer,
00109   typename pointer_traits<pointer>::template rebind<const value_type>)
00110 
00111       /**
00112        * @brief   The allocator's const pointer type.
00113        *
00114        * @c Alloc::const_pointer if that type exists, otherwise
00115        * <tt> pointer_traits<pointer>::rebind<const value_type> </tt>
00116       */
00117       typedef __const_pointer const_pointer;
00118 
00119 _GLIBCXX_ALLOC_TR_NESTED_TYPE(void_pointer,
00120   typename pointer_traits<pointer>::template rebind<void>)
00121 
00122       /**
00123        * @brief   The allocator's void pointer type.
00124        *
00125        * @c Alloc::void_pointer if that type exists, otherwise
00126        * <tt> pointer_traits<pointer>::rebind<void> </tt>
00127       */
00128       typedef __void_pointer void_pointer;
00129 
00130 _GLIBCXX_ALLOC_TR_NESTED_TYPE(const_void_pointer,
00131   typename pointer_traits<pointer>::template rebind<const void>)
00132 
00133       /**
00134        * @brief   The allocator's const void pointer type.
00135        *
00136        * @c Alloc::const_void_pointer if that type exists, otherwise
00137        * <tt> pointer_traits<pointer>::rebind<const void> </tt>
00138       */
00139       typedef __const_void_pointer const_void_pointer;
00140 
00141 _GLIBCXX_ALLOC_TR_NESTED_TYPE(difference_type,
00142                               typename pointer_traits<pointer>::difference_type)
00143 
00144       /**
00145        * @brief   The allocator's difference type
00146        *
00147        * @c Alloc::difference_type if that type exists, otherwise
00148        * <tt> pointer_traits<pointer>::difference_type </tt>
00149       */
00150       typedef __difference_type difference_type;
00151 
00152 _GLIBCXX_ALLOC_TR_NESTED_TYPE(size_type,
00153                               typename make_unsigned<difference_type>::type)
00154 
00155       /**
00156        * @brief   The allocator's size type
00157        *
00158        * @c Alloc::size_type if that type exists, otherwise
00159        * <tt> make_unsigned<difference_type>::type </tt>
00160       */
00161       typedef __size_type size_type;
00162 
00163 _GLIBCXX_ALLOC_TR_NESTED_TYPE(propagate_on_container_copy_assignment,
00164                               false_type)
00165 
00166       /**
00167        * @brief   How the allocator is propagated on copy assignment
00168        *
00169        * @c Alloc::propagate_on_container_copy_assignment if that type exists,
00170        * otherwise @c false_type
00171       */
00172       typedef __propagate_on_container_copy_assignment
00173         propagate_on_container_copy_assignment;
00174 
00175 _GLIBCXX_ALLOC_TR_NESTED_TYPE(propagate_on_container_move_assignment,
00176                               false_type)
00177 
00178       /**
00179        * @brief   How the allocator is propagated on move assignment
00180        *
00181        * @c Alloc::propagate_on_container_move_assignment if that type exists,
00182        * otherwise @c false_type
00183       */
00184       typedef __propagate_on_container_move_assignment
00185         propagate_on_container_move_assignment;
00186 
00187 _GLIBCXX_ALLOC_TR_NESTED_TYPE(propagate_on_container_swap,
00188                               false_type)
00189 
00190       /**
00191        * @brief   How the allocator is propagated on swap
00192        *
00193        * @c Alloc::propagate_on_container_swap if that type exists,
00194        * otherwise @c false_type
00195       */
00196       typedef __propagate_on_container_swap propagate_on_container_swap;
00197 
00198 #undef _GLIBCXX_ALLOC_TR_NESTED_TYPE
00199 
00200       template<typename _Tp>
00201         using rebind_alloc = typename __alloctr_rebind<_Alloc, _Tp>::__type;
00202       template<typename _Tp>
00203         using rebind_traits = allocator_traits<rebind_alloc<_Tp>>;
00204 
00205     private:
00206       template<typename _Alloc2>
00207     struct __allocate_helper
00208     {
00209       template<typename _Alloc3,
00210         typename = decltype(std::declval<_Alloc3*>()->allocate(
00211           std::declval<size_type>(),
00212           std::declval<const_void_pointer>()))>
00213         static true_type __test(int);
00214 
00215       template<typename>
00216         static false_type __test(...);
00217 
00218       typedef decltype(__test<_Alloc>(0)) type;
00219       static const bool value = type::value;
00220     };
00221 
00222       template<typename _Alloc2>
00223     static typename
00224         enable_if<__allocate_helper<_Alloc2>::value, pointer>::type
00225         _S_allocate(_Alloc2& __a, size_type __n, const_void_pointer __hint)
00226     { return __a.allocate(__n, __hint); }
00227 
00228       template<typename _Alloc2>
00229     static typename
00230         enable_if<!__allocate_helper<_Alloc2>::value, pointer>::type
00231         _S_allocate(_Alloc2& __a, size_type __n, ...)
00232     { return __a.allocate(__n); }
00233 
00234       template<typename _Tp, typename... _Args>
00235     struct __construct_helper
00236     {
00237       template<typename _Alloc2,
00238         typename = decltype(std::declval<_Alloc2*>()->construct(
00239           std::declval<_Tp*>(), std::declval<_Args>()...))>
00240         static true_type __test(int);
00241 
00242       template<typename>
00243         static false_type __test(...);
00244 
00245       typedef decltype(__test<_Alloc>(0)) type;
00246       static const bool value = type::value;
00247     };
00248 
00249       template<typename _Tp, typename... _Args>
00250     static typename
00251         enable_if<__construct_helper<_Tp, _Args...>::value, void>::type
00252         _S_construct(_Alloc& __a, _Tp* __p, _Args&&... __args)
00253     { __a.construct(__p, std::forward<_Args>(__args)...); }
00254 
00255       template<typename _Tp, typename... _Args>
00256     static typename
00257         enable_if<!__construct_helper<_Tp, _Args...>::value, void>::type
00258         _S_construct(_Alloc&, _Tp* __p, _Args&&... __args)
00259     { ::new((void*)__p) _Tp(std::forward<_Args>(__args)...); }
00260 
00261       template<typename _Tp>
00262     struct __destroy_helper
00263     {
00264       template<typename _Alloc2,
00265         typename = decltype(std::declval<_Alloc2*>()->destroy(
00266           std::declval<_Tp*>()))>
00267         static true_type __test(int);
00268 
00269       template<typename>
00270         static false_type __test(...);
00271 
00272       typedef decltype(__test<_Alloc>(0)) type;
00273       static const bool value = type::value;
00274     };
00275 
00276       template<typename _Tp>
00277     static typename enable_if<__destroy_helper<_Tp>::value, void>::type
00278         _S_destroy(_Alloc& __a, _Tp* __p)
00279     { __a.destroy(__p); }
00280 
00281       template<typename _Tp>
00282     static typename enable_if<!__destroy_helper<_Tp>::value, void>::type
00283         _S_destroy(_Alloc&, _Tp* __p)
00284     { __p->~_Tp(); }
00285 
00286       template<typename _Alloc2>
00287     struct __maxsize_helper
00288     {
00289       template<typename _Alloc3,
00290         typename = decltype(std::declval<_Alloc3*>()->max_size())>
00291         static true_type __test(int);
00292 
00293       template<typename>
00294         static false_type __test(...);
00295 
00296       typedef decltype(__test<_Alloc2>(0)) type;
00297       static const bool value = type::value;
00298     };
00299 
00300       template<typename _Alloc2>
00301     static typename
00302         enable_if<__maxsize_helper<_Alloc2>::value, size_type>::type
00303         _S_max_size(_Alloc2& __a)
00304     { return __a.max_size(); }
00305 
00306       template<typename _Alloc2>
00307     static typename
00308         enable_if<!__maxsize_helper<_Alloc2>::value, size_type>::type
00309     _S_max_size(_Alloc2&)
00310     { return __gnu_cxx::__numeric_traits<size_type>::__max; }
00311 
00312       template<typename _Alloc2>
00313     struct __select_helper
00314     {
00315       template<typename _Alloc3, typename
00316         = decltype(std::declval<_Alloc3*>()
00317         ->select_on_container_copy_construction())>
00318         static true_type __test(int);
00319 
00320       template<typename>
00321         static false_type __test(...);
00322 
00323       typedef decltype(__test<_Alloc2>(0)) type;
00324       static const bool value = type::value;
00325     };
00326       template<typename _Alloc2>
00327     static typename
00328         enable_if<__select_helper<_Alloc2>::value, _Alloc2>::type
00329         _S_select(_Alloc2& __a)
00330     { return __a.select_on_container_copy_construction(); }
00331 
00332       template<typename _Alloc2>
00333     static typename
00334         enable_if<!__select_helper<_Alloc2>::value, _Alloc2>::type
00335         _S_select(_Alloc2& __a)
00336     { return __a; }
00337 
00338     public:
00339 
00340       /**
00341        *  @brief  Allocate memory.
00342        *  @param  __a  An allocator.
00343        *  @param  __n  The number of objects to allocate space for.
00344        *
00345        *  Calls @c a.allocate(n)
00346       */
00347       static pointer
00348       allocate(_Alloc& __a, size_type __n)
00349       { return __a.allocate(__n); }
00350 
00351       /**
00352        *  @brief  Allocate memory.
00353        *  @param  __a  An allocator.
00354        *  @param  __n  The number of objects to allocate space for.
00355        *  @param  __hint Aid to locality.
00356        *  @return Memory of suitable size and alignment for @a n objects
00357        *          of type @c value_type
00358        *
00359        *  Returns <tt> a.allocate(n, hint) </tt> if that expression is
00360        *  well-formed, otherwise returns @c a.allocate(n)
00361       */
00362       static pointer
00363       allocate(_Alloc& __a, size_type __n, const_void_pointer __hint)
00364       { return _S_allocate(__a, __n, __hint); }
00365 
00366       /**
00367        *  @brief  Deallocate memory.
00368        *  @param  __a  An allocator.
00369        *  @param  __p  Pointer to the memory to deallocate.
00370        *  @param  __n  The number of objects space was allocated for.
00371        *
00372        *  Calls <tt> a.deallocate(p, n) </tt>
00373       */
00374       static void deallocate(_Alloc& __a, pointer __p, size_type __n)
00375       { __a.deallocate(__p, __n); }
00376 
00377       /**
00378        *  @brief  Construct an object of type @a _Tp
00379        *  @param  __a  An allocator.
00380        *  @param  __p  Pointer to memory of suitable size and alignment for Tp
00381        *  @param  __args Constructor arguments.
00382        *
00383        *  Calls <tt> __a.construct(__p, std::forward<Args>(__args)...) </tt>
00384        *  if that expression is well-formed, otherwise uses placement-new
00385        *  to construct an object of type @a _Tp at location @a __p from the
00386        *  arguments @a __args...
00387       */
00388       template<typename _Tp, typename... _Args>
00389     static void construct(_Alloc& __a, _Tp* __p, _Args&&... __args)
00390     { _S_construct(__a, __p, std::forward<_Args>(__args)...); }
00391 
00392       /**
00393        *  @brief  Destroy an object of type @a _Tp
00394        *  @param  __a  An allocator.
00395        *  @param  __p  Pointer to the object to destroy
00396        *
00397        *  Calls @c __a.destroy(__p) if that expression is well-formed,
00398        *  otherwise calls @c __p->~_Tp()
00399       */
00400       template <class _Tp>
00401     static void destroy(_Alloc& __a, _Tp* __p)
00402     { _S_destroy(__a, __p); }
00403 
00404       /**
00405        *  @brief  The maximum supported allocation size
00406        *  @param  __a  An allocator.
00407        *  @return @c __a.max_size() or @c numeric_limits<size_type>::max()
00408        *
00409        *  Returns @c __a.max_size() if that expression is well-formed,
00410        *  otherwise returns @c numeric_limits<size_type>::max()
00411       */
00412       static size_type max_size(const _Alloc& __a)
00413       { return _S_max_size(__a); }
00414 
00415       /**
00416        *  @brief  Obtain an allocator to use when copying a container.
00417        *  @param  __rhs  An allocator.
00418        *  @return @c __rhs.select_on_container_copy_construction() or @a __rhs
00419        *
00420        *  Returns @c __rhs.select_on_container_copy_construction() if that
00421        *  expression is well-formed, otherwise returns @a __rhs
00422       */
00423       static _Alloc
00424       select_on_container_copy_construction(const _Alloc& __rhs)
00425       { return _S_select(__rhs); }
00426     };
00427 
00428   template<typename _Alloc>
00429   template<typename _Alloc2>
00430     const bool allocator_traits<_Alloc>::__allocate_helper<_Alloc2>::value;
00431 
00432   template<typename _Alloc>
00433   template<typename _Tp, typename... _Args>
00434     const bool
00435     allocator_traits<_Alloc>::__construct_helper<_Tp, _Args...>::value;
00436 
00437   template<typename _Alloc>
00438   template<typename _Tp>
00439     const bool allocator_traits<_Alloc>::__destroy_helper<_Tp>::value;
00440 
00441   template<typename _Alloc>
00442   template<typename _Alloc2>
00443     const bool allocator_traits<_Alloc>::__maxsize_helper<_Alloc2>::value;
00444 
00445   template<typename _Alloc>
00446   template<typename _Alloc2>
00447     const bool allocator_traits<_Alloc>::__select_helper<_Alloc2>::value;
00448 
00449   template<typename _Alloc>
00450     inline void
00451     __do_alloc_on_copy(_Alloc& __one, const _Alloc& __two, true_type)
00452     { __one = __two; }
00453 
00454   template<typename _Alloc>
00455     inline void
00456     __do_alloc_on_copy(_Alloc&, const _Alloc&, false_type)
00457     { }
00458 
00459   template<typename _Alloc>
00460     inline void __alloc_on_copy(_Alloc& __one, const _Alloc& __two)
00461     {
00462       typedef allocator_traits<_Alloc> __traits;
00463       typedef typename __traits::propagate_on_container_copy_assignment __pocca;
00464       __do_alloc_on_copy(__one, __two, __pocca());
00465     }
00466 
00467   template<typename _Alloc>
00468     inline _Alloc __alloc_on_copy(const _Alloc& __a)
00469     {
00470       typedef allocator_traits<_Alloc> __traits;
00471       return __traits::select_on_container_copy_construction(__a);
00472     }
00473 
00474   template<typename _Alloc>
00475     inline void __do_alloc_on_move(_Alloc& __one, _Alloc& __two, true_type)
00476     { __one = std::move(__two); }
00477 
00478   template<typename _Alloc>
00479     inline void __do_alloc_on_move(_Alloc&, _Alloc&, false_type)
00480     { }
00481 
00482   template<typename _Alloc>
00483     inline void __alloc_on_move(_Alloc& __one, _Alloc& __two)
00484     {
00485       typedef allocator_traits<_Alloc> __traits;
00486       typedef typename __traits::propagate_on_container_move_assignment __pocma;
00487       __do_alloc_on_move(__one, __two, __pocma());
00488     }
00489 
00490   template<typename _Alloc>
00491     inline void __do_alloc_on_swap(_Alloc& __one, _Alloc& __two, true_type)
00492     {
00493       using std::swap;
00494       swap(__one, __two);
00495     }
00496 
00497   template<typename _Alloc>
00498     inline void __do_alloc_on_swap(_Alloc&, _Alloc&, false_type)
00499     { }
00500 
00501   template<typename _Alloc>
00502     inline void __alloc_on_swap(_Alloc& __one, _Alloc& __two)
00503     {
00504       typedef allocator_traits<_Alloc> __traits;
00505       typedef typename __traits::propagate_on_container_swap __pocs;
00506       __do_alloc_on_swap(__one, __two, __pocs());
00507     }
00508 
00509 _GLIBCXX_END_NAMESPACE_VERSION
00510 } // namespace std
00511 
00512 #endif
00513 #endif