1 // Allocator that wraps "C" malloc -*- C++ -*- 2 3 // Copyright (C) 2001-2019 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 _GLIBCXX20_CONSTEXPR 79 malloc_allocator() _GLIBCXX_USE_NOEXCEPT { } 80 81 _GLIBCXX20_CONSTEXPR 82 malloc_allocator(const malloc_allocator&) _GLIBCXX_USE_NOEXCEPT { } 83 84 template<typename _Tp1> 85 _GLIBCXX20_CONSTEXPR 86 malloc_allocator(const malloc_allocator<_Tp1>&) 87 _GLIBCXX_USE_NOEXCEPT { } 88 89 ~malloc_allocator() _GLIBCXX_USE_NOEXCEPT { } 90 91 pointer 92 address(reference __x) const _GLIBCXX_NOEXCEPT 93 { return std::__addressof(__x); } 94 95 const_pointer 96 address(const_reference __x) const _GLIBCXX_NOEXCEPT 97 { return std::__addressof(__x); } 98 99 // NB: __n is permitted to be 0. The C++ standard says nothing 100 // about what the return value is when __n == 0. 101 pointer 102 allocate(size_type __n, const void* = 0) 103 { 104 if (__n > this->max_size()) 105 std::__throw_bad_alloc(); 106 107 pointer __ret = 0; 108 #if __cpp_aligned_new 109 #if __cplusplus > 201402L && _GLIBCXX_HAVE_ALIGNED_ALLOC 110 if (alignof(_Tp) > alignof(std::max_align_t)) 111 { 112 __ret = static_cast<_Tp*>(::aligned_alloc(alignof(_Tp), 113 __n * sizeof(_Tp))); 114 } 115 #else 116 # define _GLIBCXX_CHECK_MALLOC_RESULT 117 #endif 118 #endif 119 if (!__ret) 120 __ret = static_cast<_Tp*>(std::malloc(__n * sizeof(_Tp))); 121 if (!__ret) 122 std::__throw_bad_alloc(); 123 #ifdef _GLIBCXX_CHECK_MALLOC_RESULT 124 #undef _GLIBCXX_CHECK_MALLOC_RESULT 125 if (reinterpret_cast<std::size_t>(__ret) % alignof(_Tp)) 126 { 127 // Memory returned by malloc is not suitably aligned for _Tp. 128 deallocate(__ret, __n); 129 std::__throw_bad_alloc(); 130 } 131 #endif 132 return __ret; 133 } 134 135 // __p is not permitted to be a null pointer. 136 void 137 deallocate(pointer __p, size_type) 138 { std::free(static_cast<void*>(__p)); } 139 140 size_type 141 max_size() const _GLIBCXX_USE_NOEXCEPT 142 { 143 #if __PTRDIFF_MAX__ < __SIZE_MAX__ 144 return size_t(__PTRDIFF_MAX__) / sizeof(_Tp); 145 #else 146 return size_t(-1) / sizeof(_Tp); 147 #endif 148 } 149 150 #if __cplusplus >= 201103L 151 template<typename _Up, typename... _Args> 152 void 153 construct(_Up* __p, _Args&&... __args) 154 noexcept(noexcept(::new((void *)__p) 155 _Up(std::forward<_Args>(__args)...))) 156 { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); } 157 158 template<typename _Up> 159 void 160 destroy(_Up* __p) 161 noexcept(noexcept(__p->~_Up())) 162 { __p->~_Up(); } 163 #else 164 // _GLIBCXX_RESOLVE_LIB_DEFECTS 165 // 402. wrong new expression in [some_] allocator::construct 166 void 167 construct(pointer __p, const _Tp& __val) 168 { ::new((void *)__p) value_type(__val); } 169 170 void 171 destroy(pointer __p) { __p->~_Tp(); } 172 #endif 173 174 template<typename _Up> 175 friend bool 176 operator==(const malloc_allocator&, const malloc_allocator<_Up>&) 177 _GLIBCXX_NOTHROW 178 { return true; } 179 180 template<typename _Up> 181 friend bool 182 operator!=(const malloc_allocator&, const malloc_allocator<_Up>&) 183 _GLIBCXX_NOTHROW 184 { return false; } 185 }; 186 187 _GLIBCXX_END_NAMESPACE_VERSION 188 } // namespace 189 190 #endif 191