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