boost/serialization/detail/shared_ptr_nmt_132.hpp

   1 #ifndef BOOST_DETAIL_SHARED_PTR_NMT_132_HPP_INCLUDED
   2 #define BOOST_DETAIL_SHARED_PTR_NMT_132_HPP_INCLUDED
   3
   4 //
   5 //  detail/shared_ptr_nmt.hpp - shared_ptr.hpp without member templates
   6 //
   7 //  (C) Copyright Greg Colvin and Beman Dawes 1998, 1999.
   8 //  Copyright (c) 2001, 2002 Peter Dimov
   9 //
  10 //  Distributed under the Boost Software License, Version 1.0. (See
  11 //  accompanying file LICENSE_1_0.txt or copy at
  12 //  http://www.boost.org/LICENSE_1_0.txt)
  13 //
  14 //  See http://www.boost.org/libs/smart_ptr/shared_ptr.htm for documentation.
  15 //
  16
  17 #include <boost/assert.hpp>
  18 #include <boost/checked_delete.hpp>
  19 #include <boost/serialization/throw_exception.hpp>
  20 #include <boost/detail/atomic_count.hpp>
  21
  22 #ifndef BOOST_NO_AUTO_PTR
  23 # include <memory>          // for std::auto_ptr
  24 #endif
  25
  26 #include <algorithm>        // for std::swap
  27 #include <functional>       // for std::less
  28 #include <new>              // for std::bad_alloc
  29
  30 namespace boost
  31 {
  32
  33 template<class T> class shared_ptr
  34 {
  35 private:
  36
  37     typedef detail::atomic_count count_type;
  38
  39 public:
  40
  41     typedef T element_type;
  42     typedef T value_type;
  43
  44     explicit shared_ptr(T * p = 0): px(p)
  45     {
  46 #ifndef BOOST_NO_EXCEPTIONS
  47
  48         try  // prevent leak if new throws
  49         {
  50             pn = new count_type(1);
  51         }
  52         catch(...)
  53         {
  54             boost::checked_delete(p);
  55             throw;
  56         }
  57
  58 #else
  59
  60         pn = new count_type(1);
  61
  62         if(pn == 0)
  63         {
  64             boost::checked_delete(p);
  65             boost::serialization::throw_exception(std::bad_alloc());
  66         }
  67
  68 #endif
  69     }
  70
  71     ~shared_ptr()
  72     {
  73         if(--*pn == 0)
  74         {
  75             boost::checked_delete(px);
  76             delete pn;
  77         }
  78     }
  79
  80     shared_ptr(shared_ptr const & r): px(r.px)  // never throws
  81     {
  82         pn = r.pn;
  83         ++*pn;
  84     }
  85
  86     shared_ptr & operator=(shared_ptr const & r)
  87     {
  88         shared_ptr(r).swap(*this);
  89         return *this;
  90     }
  91
  92 #ifndef BOOST_NO_AUTO_PTR
  93
  94     explicit shared_ptr(std::auto_ptr<T> & r)
  95     {
  96         pn = new count_type(1); // may throw
  97         px = r.release(); // fix: moved here to stop leak if new throws
  98     }
  99
 100     shared_ptr & operator=(std::auto_ptr<T> & r)
 101     {
 102         shared_ptr(r).swap(*this);
 103         return *this;
 104     }
 105
 106 #endif
 107
 108     void reset(T * p = 0)
 109     {
 110         BOOST_ASSERT(p == 0 || p != px);
 111         shared_ptr(p).swap(*this);
 112     }
 113
 114     T & operator*() const  // never throws
 115     {
 116         BOOST_ASSERT(px != 0);
 117         return *px;
 118     }
 119
 120     T * operator->() const  // never throws
 121     {
 122         BOOST_ASSERT(px != 0);
 123         return px;
 124     }
 125
 126     T * get() const  // never throws
 127     {
 128         return px;
 129     }
 130
 131     long use_count() const  // never throws
 132     {
 133         return *pn;
 134     }
 135
 136     bool unique() const  // never throws
 137     {
 138         return *pn == 1;
 139     }
 140
 141     void swap(shared_ptr<T> & other)  // never throws
 142     {
 143         std::swap(px, other.px);
 144         std::swap(pn, other.pn);
 145     }
 146
 147 private:
 148
 149     T * px;            // contained pointer
 150     count_type * pn;   // ptr to reference counter
 151 };
 152
 153 template<class T, class U> inline bool operator==(shared_ptr<T> const & a, shared_ptr<U> const & b)
 154 {
 155     return a.get() == b.get();
 156 }
 157
 158 template<class T, class U> inline bool operator!=(shared_ptr<T> const & a, shared_ptr<U> const & b)
 159 {
 160     return a.get() != b.get();
 161 }
 162
 163 template<class T> inline bool operator<(shared_ptr<T> const & a, shared_ptr<T> const & b)
 164 {
 165     return std::less<T*>()(a.get(), b.get());
 166 }
 167
 168 template<class T> void swap(shared_ptr<T> & a, shared_ptr<T> & b)
 169 {
 170     a.swap(b);
 171 }
 172
 173 // get_pointer() enables boost::mem_fn to recognize shared_ptr
 174
 175 template<class T> inline T * get_pointer(shared_ptr<T> const & p)
 176 {
 177     return p.get();
 178 }
 179
 180 } // namespace boost
 181
 182 #endif  // #ifndef BOOST_DETAIL_SHARED_PTR_NMT_132_HPP_INCLUDED