libstdc++-v3/include/ext/malloc_allocator.h

   1 // Allocator that wraps "C" malloc -*- C++ -*-
   2
   3 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
   4 // Free Software Foundation, Inc.
   5 //
   6 // This file is part of the GNU ISO C++ Library.  This library is free
   7 // software; you can redistribute it and/or modify it under the
   8 // terms of the GNU General Public License as published by the
   9 // Free Software Foundation; either version 2, or (at your option)
  10 // any later version.
  11
  12 // This library is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16
  17 // You should have received a copy of the GNU General Public License along
  18 // with this library; see the file COPYING.  If not, write to the Free
  19 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  20 // USA.
  21
  22 // As a special exception, you may use this file as part of a free software
  23 // library without restriction.  Specifically, if other files instantiate
  24 // templates or use macros or inline functions from this file, or you compile
  25 // this file and link it with other files to produce an executable, this
  26 // file does not by itself cause the resulting executable to be covered by
  27 // the GNU General Public License.  This exception does not however
  28 // invalidate any other reasons why the executable file might be covered by
  29 // the GNU General Public License.
  30
  31 /** @file ext/malloc_allocator.h
  32  *  This file is a GNU extension to the Standard C++ Library.
  33  */
  34
  35 #ifndef _MALLOC_ALLOCATOR_H
  36 #define _MALLOC_ALLOCATOR_H 1
  37
  38 #include <cstdlib>
  39 #include <new>
  40 #include <bits/functexcept.h>
  41 #include <bits/move.h>
  42
  43 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
  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       malloc_allocator() throw() { }
  73
  74       malloc_allocator(const malloc_allocator&) throw() { }
  75
  76       template<typename _Tp1>
  77         malloc_allocator(const malloc_allocator<_Tp1>&) throw() { }
  78
  79       ~malloc_allocator() throw() { }
  80
  81       pointer
  82       address(reference __x) const { return &__x; }
  83
  84       const_pointer
  85       address(const_reference __x) const { return &__x; }
  86
  87       // NB: __n is permitted to be 0.  The C++ standard says nothing
  88       // about what the return value is when __n == 0.
  89       pointer
  90       allocate(size_type __n, const void* = 0)
  91       {
  92         if (__builtin_expect(__n > this->max_size(), false))
  93           std::__throw_bad_alloc();
  94
  95         pointer __ret = static_cast<_Tp*>(std::malloc(__n * sizeof(_Tp)));
  96         if (!__ret)
  97           std::__throw_bad_alloc();
  98         return __ret;
  99       }
 100
 101       // __p is not permitted to be a null pointer.
 102       void
 103       deallocate(pointer __p, size_type)
 104       { std::free(static_cast<void*>(__p)); }
 105
 106       size_type
 107       max_size() const throw()
 108       { return size_t(-1) / sizeof(_Tp); }
 109
 110       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 111       // 402. wrong new expression in [some_] allocator::construct
 112       void
 113       construct(pointer __p, const _Tp& __val)
 114       { ::new((void *)__p) value_type(__val); }
 115
 116 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 117       template<typename... _Args>
 118         void
 119         construct(pointer __p, _Args&&... __args)
 120         { ::new((void *)__p) _Tp(std::forward<_Args>(__args)...); }
 121 #endif
 122
 123       void
 124       destroy(pointer __p) { __p->~_Tp(); }
 125     };
 126
 127   template<typename _Tp>
 128     inline bool
 129     operator==(const malloc_allocator<_Tp>&, const malloc_allocator<_Tp>&)
 130     { return true; }
 131
 132   template<typename _Tp>
 133     inline bool
 134     operator!=(const malloc_allocator<_Tp>&, const malloc_allocator<_Tp>&)
 135     { return false; }
 136
 137 _GLIBCXX_END_NAMESPACE
 138
 139 #endif