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

   1 // Allocator that wraps "C" malloc -*- C++ -*-
   2
   3 // Copyright (C) 2001, 2002, 2003, 2004 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 2, 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 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING.  If not, write to the Free
  18 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  19 // USA.
  20
  21 // As a special exception, you may use this file as part of a free software
  22 // library without restriction.  Specifically, if other files instantiate
  23 // templates or use macros or inline functions from this file, or you compile
  24 // this file and link it with other files to produce an executable, this
  25 // file does not by itself cause the resulting executable to be covered by
  26 // the GNU General Public License.  This exception does not however
  27 // invalidate any other reasons why the executable file might be covered by
  28 // the GNU General Public License.
  29
  30 #ifndef _MALLOC_ALLOCATOR_H
  31 #define _MALLOC_ALLOCATOR_H 1
  32
  33 #include <new>
  34
  35 namespace __gnu_cxx
  36 {
  37   /**
  38    *  @brief  An allocator that uses malloc
  39    *
  40    *  This is precisely the allocator defined in the C++ Standard.
  41    *    - all allocation calls malloc
  42    *    - all deallocation calls free
  43    *
  44    *  (See @link Allocators allocators info @endlink for more.)
  45    */
  46   template<typename _Tp>
  47     class malloc_allocator
  48     {
  49     public:
  50       typedef size_t     size_type;
  51       typedef ptrdiff_t  difference_type;
  52       typedef _Tp*       pointer;
  53       typedef const _Tp* const_pointer;
  54       typedef _Tp&       reference;
  55       typedef const _Tp& const_reference;
  56       typedef _Tp        value_type;
  57
  58       template<typename _Tp1>
  59         struct rebind
  60         { typedef malloc_allocator<_Tp1> other; };
  61
  62       malloc_allocator() throw() { }
  63
  64       malloc_allocator(const malloc_allocator&) throw() { }
  65
  66       template<typename _Tp1>
  67         malloc_allocator(const malloc_allocator<_Tp1>&) throw() { }
  68
  69       ~malloc_allocator() throw() { }
  70
  71       pointer
  72       address(reference __x) const { return &__x; }
  73
  74       const_pointer
  75       address(const_reference __x) const { return &__x; }
  76
  77       // NB: __n is permitted to be 0.  The C++ standard says nothing
  78       // about what the return value is when __n == 0.
  79       pointer
  80       allocate(size_type __n, const void* = 0)
  81       {
  82         pointer __ret = static_cast<_Tp*>(malloc(__n * sizeof(_Tp)));
  83         if (!__ret)
  84           throw std::bad_alloc();
  85         return __ret;
  86       }
  87
  88       // __p is not permitted to be a null pointer.
  89       void
  90       deallocate(pointer __p, size_type)
  91       { free(static_cast<void*>(__p)); }
  92
  93       size_type
  94       max_size() const throw()
  95       { return size_t(-1) / sizeof(_Tp); }
  96
  97       // _GLIBCXX_RESOLVE_LIB_DEFECTS
  98       // 402. wrong new expression in [some_] allocator::construct
  99       void
 100       construct(pointer __p, const _Tp& __val)
 101       { ::new(__p) value_type(__val); }
 102
 103       void
 104       destroy(pointer __p) { __p->~_Tp(); }
 105     };
 106
 107   template<typename _Tp>
 108     inline bool
 109     operator==(const malloc_allocator<_Tp>&, const malloc_allocator<_Tp>&)
 110     { return true; }
 111
 112   template<typename _Tp>
 113     inline bool
 114     operator!=(const malloc_allocator<_Tp>&, const malloc_allocator<_Tp>&)
 115     { return false; }
 116 } // namespace __gnu_cxx
 117
 118 #endif