libstdc++
malloc_allocator.h
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00001 // Allocator that wraps "C" malloc -*- C++ -*-
00002 
00003 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009,
00004 // 2010, 2011
00005 // Free Software Foundation, Inc.
00006 //
00007 // This file is part of the GNU ISO C++ Library.  This library is free
00008 // software; you can redistribute it and/or modify it under the
00009 // terms of the GNU General Public License as published by the
00010 // Free Software Foundation; either version 3, or (at your option)
00011 // any later version.
00012 
00013 // This library is distributed in the hope that it will be useful,
00014 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00015 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00016 // GNU General Public License for more details.
00017 
00018 // Under Section 7 of GPL version 3, you are granted additional
00019 // permissions described in the GCC Runtime Library Exception, version
00020 // 3.1, as published by the Free Software Foundation.
00021 
00022 // You should have received a copy of the GNU General Public License and
00023 // a copy of the GCC Runtime Library Exception along with this program;
00024 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
00025 // <http://www.gnu.org/licenses/>.
00026 
00027 /** @file ext/malloc_allocator.h
00028  *  This file is a GNU extension to the Standard C++ Library.
00029  */
00030 
00031 #ifndef _MALLOC_ALLOCATOR_H
00032 #define _MALLOC_ALLOCATOR_H 1
00033 
00034 #include <cstdlib>
00035 #include <new>
00036 #include <bits/functexcept.h>
00037 #include <bits/move.h>
00038 
00039 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
00040 {
00041 _GLIBCXX_BEGIN_NAMESPACE_VERSION
00042 
00043   using std::size_t;
00044   using std::ptrdiff_t;
00045 
00046   /**
00047    *  @brief  An allocator that uses malloc.
00048    *  @ingroup allocators
00049    *
00050    *  This is precisely the allocator defined in the C++ Standard. 
00051    *    - all allocation calls malloc
00052    *    - all deallocation calls free
00053    */
00054   template<typename _Tp>
00055     class malloc_allocator
00056     {
00057     public:
00058       typedef size_t     size_type;
00059       typedef ptrdiff_t  difference_type;
00060       typedef _Tp*       pointer;
00061       typedef const _Tp* const_pointer;
00062       typedef _Tp&       reference;
00063       typedef const _Tp& const_reference;
00064       typedef _Tp        value_type;
00065 
00066       template<typename _Tp1>
00067         struct rebind
00068         { typedef malloc_allocator<_Tp1> other; };
00069 
00070       malloc_allocator() _GLIBCXX_USE_NOEXCEPT { }
00071 
00072       malloc_allocator(const malloc_allocator&) _GLIBCXX_USE_NOEXCEPT { }
00073 
00074       template<typename _Tp1>
00075         malloc_allocator(const malloc_allocator<_Tp1>&)
00076     _GLIBCXX_USE_NOEXCEPT { }
00077 
00078       ~malloc_allocator() _GLIBCXX_USE_NOEXCEPT { }
00079 
00080       pointer
00081       address(reference __x) const _GLIBCXX_NOEXCEPT
00082       { return std::__addressof(__x); }
00083 
00084       const_pointer
00085       address(const_reference __x) const _GLIBCXX_NOEXCEPT
00086       { return std::__addressof(__x); }
00087 
00088       // NB: __n is permitted to be 0.  The C++ standard says nothing
00089       // about what the return value is when __n == 0.
00090       pointer
00091       allocate(size_type __n, const void* = 0)
00092       {
00093     if (__n > this->max_size())
00094       std::__throw_bad_alloc();
00095 
00096     pointer __ret = static_cast<_Tp*>(std::malloc(__n * sizeof(_Tp)));
00097     if (!__ret)
00098       std::__throw_bad_alloc();
00099     return __ret;
00100       }
00101 
00102       // __p is not permitted to be a null pointer.
00103       void
00104       deallocate(pointer __p, size_type)
00105       { std::free(static_cast<void*>(__p)); }
00106 
00107       size_type
00108       max_size() const _GLIBCXX_USE_NOEXCEPT 
00109       { return size_t(-1) / sizeof(_Tp); }
00110 
00111 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00112       template<typename _Up, typename... _Args>
00113         void
00114         construct(_Up* __p, _Args&&... __args)
00115     { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
00116 
00117       template<typename _Up>
00118         void 
00119         destroy(_Up* __p) { __p->~_Up(); }
00120 #else
00121       // _GLIBCXX_RESOLVE_LIB_DEFECTS
00122       // 402. wrong new expression in [some_] allocator::construct
00123       void 
00124       construct(pointer __p, const _Tp& __val) 
00125       { ::new((void *)__p) value_type(__val); }
00126 
00127       void 
00128       destroy(pointer __p) { __p->~_Tp(); }
00129 #endif
00130     };
00131 
00132   template<typename _Tp>
00133     inline bool
00134     operator==(const malloc_allocator<_Tp>&, const malloc_allocator<_Tp>&)
00135     { return true; }
00136   
00137   template<typename _Tp>
00138     inline bool
00139     operator!=(const malloc_allocator<_Tp>&, const malloc_allocator<_Tp>&)
00140     { return false; }
00141 
00142 _GLIBCXX_END_NAMESPACE_VERSION
00143 } // namespace
00144 
00145 #endif