1 // Allocator that wraps "C" malloc -*- C++ -*- 2 3 // Copyright (C) 2001-2018 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 ext/malloc_allocator.h 26 * This file is a GNU extension to the Standard C++ Library. 27 */ 28 29 #ifndef _MALLOC_ALLOCATOR_H 30 #define _MALLOC_ALLOCATOR_H 1 31 32 #include <cstdlib> 33 #include <cstddef> 34 #include <new> 35 #include <bits/functexcept.h> 36 #include <bits/move.h> 37 #if __cplusplus >= 201103L 38 #include <type_traits> 39 #endif 40 41 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) 42 { 43 _GLIBCXX_BEGIN_NAMESPACE_VERSION 44 45 using std::size_t; 46 using std::ptrdiff_t; 47 48 /** 49 * @brief An allocator that uses malloc. 50 * @ingroup allocators 51 * 52 * This is precisely the allocator defined in the C++ Standard. 53 * - all allocation calls malloc 54 * - all deallocation calls free 55 */ 56 template<typename _Tp> 57 class malloc_allocator 58 { 59 public: 60 typedef size_t size_type; 61 typedef ptrdiff_t difference_type; 62 typedef _Tp* pointer; 63 typedef const _Tp* const_pointer; 64 typedef _Tp& reference; 65 typedef const _Tp& const_reference; 66 typedef _Tp value_type; 67 68 template<typename _Tp1> 69 struct rebind 70 { typedef malloc_allocator<_Tp1> other; }; 71 72 #if __cplusplus >= 201103L 73 // _GLIBCXX_RESOLVE_LIB_DEFECTS 74 // 2103. propagate_on_container_move_assignment 75 typedef std::true_type propagate_on_container_move_assignment; 76 #endif 77 78 malloc_allocator() _GLIBCXX_USE_NOEXCEPT { } 79 80 malloc_allocator(const malloc_allocator&) _GLIBCXX_USE_NOEXCEPT { } 81 82 template<typename _Tp1> 83 malloc_allocator(const malloc_allocator<_Tp1>&) 84 _GLIBCXX_USE_NOEXCEPT { } 85 86 ~malloc_allocator() _GLIBCXX_USE_NOEXCEPT { } 87 88 pointer 89 address(reference __x) const _GLIBCXX_NOEXCEPT 90 { return std::__addressof(__x); } 91 92 const_pointer 93 address(const_reference __x) const _GLIBCXX_NOEXCEPT 94 { return std::__addressof(__x); } 95 96 // NB: __n is permitted to be 0. The C++ standard says nothing 97 // about what the return value is when __n == 0. 98 pointer 99 allocate(size_type __n, const void* = 0) 100 { 101 if (__n > this->max_size()) 102 std::__throw_bad_alloc(); 103 104 pointer __ret = 0; 105 #if __cpp_aligned_new 106 #if __cplusplus > 201402L && _GLIBCXX_HAVE_ALIGNED_ALLOC 107 if (alignof(_Tp) > alignof(std::max_align_t)) 108 { 109 __ret = static_cast<_Tp*>(::aligned_alloc(alignof(_Tp), 110 __n * sizeof(_Tp))); 111 } 112 #else 113 # define _GLIBCXX_CHECK_MALLOC_RESULT 114 #endif 115 #endif 116 if (!__ret) 117 __ret = static_cast<_Tp*>(std::malloc(__n * sizeof(_Tp))); 118 if (!__ret) 119 std::__throw_bad_alloc(); 120 #ifdef _GLIBCXX_CHECK_MALLOC_RESULT 121 #undef _GLIBCXX_CHECK_MALLOC_RESULT 122 if (reinterpret_cast<std::size_t>(__ret) % alignof(_Tp)) 123 { 124 // Memory returned by malloc is not suitably aligned for _Tp. 125 deallocate(__ret, __n); 126 std::__throw_bad_alloc(); 127 } 128 #endif 129 return __ret; 130 } 131 132 // __p is not permitted to be a null pointer. 133 void 134 deallocate(pointer __p, size_type) 135 { std::free(static_cast<void*>(__p)); } 136 137 size_type 138 max_size() const _GLIBCXX_USE_NOEXCEPT 139 { return size_t(-1) / sizeof(_Tp); } 140 141 #if __cplusplus >= 201103L 142 template<typename _Up, typename... _Args> 143 void 144 construct(_Up* __p, _Args&&... __args) 145 { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); } 146 147 template<typename _Up> 148 void 149 destroy(_Up* __p) { __p->~_Up(); } 150 #else 151 // _GLIBCXX_RESOLVE_LIB_DEFECTS 152 // 402. wrong new expression in [some_] allocator::construct 153 void 154 construct(pointer __p, const _Tp& __val) 155 { ::new((void *)__p) value_type(__val); } 156 157 void 158 destroy(pointer __p) { __p->~_Tp(); } 159 #endif 160 }; 161 162 template<typename _Tp> 163 inline bool 164 operator==(const malloc_allocator<_Tp>&, const malloc_allocator<_Tp>&) 165 { return true; } 166 167 template<typename _Tp> 168 inline bool 169 operator!=(const malloc_allocator<_Tp>&, const malloc_allocator<_Tp>&) 170 { return false; } 171 172 _GLIBCXX_END_NAMESPACE_VERSION 173 } // namespace 174 175 #endif 176