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

   1 // array allocator -*- C++ -*-
   2
   3 // Copyright (C) 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 _ARRAY_ALLOCATOR_H
  31 #define _ARRAY_ALLOCATOR_H 1
  32
  33 #include <cstddef>
  34 #include <new>
  35 #include <bits/functexcept.h>
  36 #include <tr1/array>
  37
  38 namespace __gnu_cxx
  39 {
  40   /// @brief  Base class.
  41  template<typename _Tp>
  42     class array_allocator_base
  43     {
  44     public:
  45       typedef size_t     size_type;
  46       typedef ptrdiff_t  difference_type;
  47       typedef _Tp*       pointer;
  48       typedef const _Tp* const_pointer;
  49       typedef _Tp&       reference;
  50       typedef const _Tp& const_reference;
  51       typedef _Tp        value_type;
  52
  53       pointer
  54       address(reference __x) const { return &__x; }
  55
  56       const_pointer
  57       address(const_reference __x) const { return &__x; }
  58
  59       void
  60       deallocate(pointer, size_type)
  61       {
  62         // Does nothing.
  63       }
  64
  65       size_type
  66       max_size() const throw()
  67       { return size_t(-1) / sizeof(_Tp); }
  68
  69       // _GLIBCXX_RESOLVE_LIB_DEFECTS
  70       // 402. wrong new expression in [some_] allocator::construct
  71       void
  72       construct(pointer __p, const _Tp& __val)
  73       { ::new(__p) value_type(__val); }
  74
  75       void
  76       destroy(pointer __p) { __p->~_Tp(); }
  77     };
  78
  79   /**
  80    *  @brief  An allocator that uses previously allocated memory.
  81    *  This memory can be externally, globally, or otherwise allocated.
  82    */
  83   template<typename _Tp, typename _Array = std::tr1::array<_Tp> >
  84     class array_allocator : public array_allocator_base<_Tp>
  85     {
  86     public:
  87       typedef size_t     size_type;
  88       typedef ptrdiff_t  difference_type;
  89       typedef _Tp*       pointer;
  90       typedef const _Tp* const_pointer;
  91       typedef _Tp&       reference;
  92       typedef const _Tp& const_reference;
  93       typedef _Tp        value_type;
  94
  95       typedef _Array    array_type;
  96
  97       array_type* _M_array;
  98
  99      template<typename _Tp1, typename _Array1 = _Array>
 100         struct rebind
 101         { typedef array_allocator<_Tp1, _Array1> other; };
 102
 103       array_allocator(array_type* __array = NULL) throw()
 104       : _M_array(__array)
 105       { }
 106
 107       array_allocator(const array_allocator& __o)  throw()
 108       : _M_array(__o._M_array) { }
 109
 110       template<typename _Tp1, typename _Array1>
 111         array_allocator(const array_allocator<_Tp1, _Array1>&) throw()
 112         : _M_array(NULL) { }
 113
 114       ~array_allocator() throw() { }
 115
 116       pointer
 117       allocate(size_type __n, const void* = 0)
 118       {
 119         static size_type __used;
 120         if (_M_array == 0 || __used + __n > _M_array->size())
 121           std::__throw_bad_alloc();
 122         pointer __ret = _M_array->begin() + __used;
 123         __used += __n;
 124         return __ret;
 125       }
 126     };
 127
 128   template<typename _Tp, typename _Array>
 129     inline bool
 130     operator==(const array_allocator<_Tp, _Array>&,
 131                const array_allocator<_Tp, _Array>&)
 132     { return true; }
 133
 134   template<typename _Tp, typename _Array>
 135     inline bool
 136     operator!=(const array_allocator<_Tp, _Array>&,
 137                const array_allocator<_Tp, _Array>&)
 138     { return false; }
 139 } // namespace __gnu_cxx
 140
 141 #endif