gnu/dist/gcc4/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, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  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 /** @file ext/malloc_allocator.h
  31  *  This file is a GNU extension to the Standard C++ Library.
  32  */
  33
  34 #ifndef _MALLOC_ALLOCATOR_H
  35 #define _MALLOC_ALLOCATOR_H 1
  36
  37 #include <cstdlib>
  38 #include <new>
  39 #include <bits/functexcept.h>
  40
  41 namespace __gnu_cxx
  42 {
  43   /**
  44    *  @brief  An allocator that uses malloc.
  45    *
  46    *  This is precisely the allocator defined in the C++ Standard.
  47    *    - all allocation calls malloc
  48    *    - all deallocation calls free
  49    */
  50   template<typename _Tp>
  51     class malloc_allocator
  52     {
  53     public:
  54       typedef size_t     size_type;
  55       typedef ptrdiff_t  difference_type;
  56       typedef _Tp*       pointer;
  57       typedef const _Tp* const_pointer;
  58       typedef _Tp&       reference;
  59       typedef const _Tp& const_reference;
  60       typedef _Tp        value_type;
  61
  62       template<typename _Tp1>
  63         struct rebind
  64         { typedef malloc_allocator<_Tp1> other; };
  65
  66       malloc_allocator() throw() { }
  67
  68       malloc_allocator(const malloc_allocator&) throw() { }
  69
  70       template<typename _Tp1>
  71         malloc_allocator(const malloc_allocator<_Tp1>&) throw() { }
  72
  73       ~malloc_allocator() throw() { }
  74
  75       pointer
  76       address(reference __x) const { return &__x; }
  77
  78       const_pointer
  79       address(const_reference __x) const { return &__x; }
  80
  81       // NB: __n is permitted to be 0.  The C++ standard says nothing
  82       // about what the return value is when __n == 0.
  83       pointer
  84       allocate(size_type __n, const void* = 0)
  85       {
  86         if (__builtin_expect(__n > this->max_size(), false))
  87           std::__throw_bad_alloc();
  88
  89         pointer __ret = static_cast<_Tp*>(malloc(__n * sizeof(_Tp)));
  90         if (!__ret)
  91           std::__throw_bad_alloc();
  92         return __ret;
  93       }
  94
  95       // __p is not permitted to be a null pointer.
  96       void
  97       deallocate(pointer __p, size_type)
  98       { free(static_cast<void*>(__p)); }
  99
 100       size_type
 101       max_size() const throw()
 102       { return size_t(-1) / sizeof(_Tp); }
 103
 104       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 105       // 402. wrong new expression in [some_] allocator::construct
 106       void
 107       construct(pointer __p, const _Tp& __val)
 108       { ::new(__p) value_type(__val); }
 109
 110       void
 111       destroy(pointer __p) { __p->~_Tp(); }
 112     };
 113
 114   template<typename _Tp>
 115     inline bool
 116     operator==(const malloc_allocator<_Tp>&, const malloc_allocator<_Tp>&)
 117     { return true; }
 118
 119   template<typename _Tp>
 120     inline bool
 121     operator!=(const malloc_allocator<_Tp>&, const malloc_allocator<_Tp>&)
 122     { return false; }
 123 } // namespace __gnu_cxx
 124
 125 #endif