ceph/src/boost/boost/smart_ptr/detail/sp_counted_base_cw_x86.hpp

   1 #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_CW_X86_HPP_INCLUDED
   2 #define BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_CW_X86_HPP_INCLUDED
   3
   4 // MS compatible compilers support #pragma once
   5
   6 #if defined(_MSC_VER) && (_MSC_VER >= 1020)
   7 # pragma once
   8 #endif
   9
  10 //
  11 //  detail/sp_counted_base_cw_x86.hpp - CodeWarrion on 486+
  12 //
  13 //  Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
  14 //  Copyright 2004-2005 Peter Dimov
  15 //  Copyright 2005 Rene Rivera
  16 //
  17 //  Distributed under the Boost Software License, Version 1.0. (See
  18 //  accompanying file LICENSE_1_0.txt or copy at
  19 //  http://www.boost.org/LICENSE_1_0.txt)
  20 //
  21 //
  22 //  Lock-free algorithm by Alexander Terekhov
  23 //
  24 //  Thanks to Ben Hitchings for the #weak + (#shared != 0)
  25 //  formulation
  26 //
  27
  28 #include <boost/detail/sp_typeinfo.hpp>
  29
  30 namespace boost
  31 {
  32
  33 namespace detail
  34 {
  35
  36 inline int atomic_exchange_and_add( int * pw, int dv )
  37 {
  38     // int r = *pw;
  39     // *pw += dv;
  40     // return r;
  41
  42     asm
  43     {
  44         mov esi, [pw]
  45         mov eax, dv
  46         lock xadd dword ptr [esi], eax
  47     }
  48 }
  49
  50 inline void atomic_increment( int * pw )
  51 {
  52     //atomic_exchange_and_add( pw, 1 );
  53
  54     asm
  55     {
  56         mov esi, [pw]
  57         lock inc dword ptr [esi]
  58     }
  59 }
  60
  61 inline int atomic_conditional_increment( int * pw )
  62 {
  63     // int rv = *pw;
  64     // if( rv != 0 ) ++*pw;
  65     // return rv;
  66
  67     asm
  68     {
  69         mov esi, [pw]
  70         mov eax, dword ptr [esi]
  71     L0:
  72         test eax, eax
  73         je L1
  74         mov ebx, eax
  75         inc ebx
  76         lock cmpxchg dword ptr [esi], ebx
  77         jne L0
  78     L1:
  79     }
  80 }
  81
  82 class sp_counted_base
  83 {
  84 private:
  85
  86     sp_counted_base( sp_counted_base const & );
  87     sp_counted_base & operator= ( sp_counted_base const & );
  88
  89     int use_count_;        // #shared
  90     int weak_count_;       // #weak + (#shared != 0)
  91
  92 public:
  93
  94     sp_counted_base(): use_count_( 1 ), weak_count_( 1 )
  95     {
  96     }
  97
  98     virtual ~sp_counted_base() // nothrow
  99     {
 100     }
 101
 102     // dispose() is called when use_count_ drops to zero, to release
 103     // the resources managed by *this.
 104
 105     virtual void dispose() = 0; // nothrow
 106
 107     // destroy() is called when weak_count_ drops to zero.
 108
 109     virtual void destroy() // nothrow
 110     {
 111         delete this;
 112     }
 113
 114     virtual void * get_deleter( sp_typeinfo const & ti ) = 0;
 115     virtual void * get_local_deleter( sp_typeinfo const & ti ) = 0;
 116     virtual void * get_untyped_deleter() = 0;
 117
 118     void add_ref_copy()
 119     {
 120         atomic_increment( &use_count_ );
 121     }
 122
 123     bool add_ref_lock() // true on success
 124     {
 125         return atomic_conditional_increment( &use_count_ ) != 0;
 126     }
 127
 128     void release() // nothrow
 129     {
 130         if( atomic_exchange_and_add( &use_count_, -1 ) == 1 )
 131         {
 132             dispose();
 133             weak_release();
 134         }
 135     }
 136
 137     void weak_add_ref() // nothrow
 138     {
 139         atomic_increment( &weak_count_ );
 140     }
 141
 142     void weak_release() // nothrow
 143     {
 144         if( atomic_exchange_and_add( &weak_count_, -1 ) == 1 )
 145         {
 146             destroy();
 147         }
 148     }
 149
 150     long use_count() const // nothrow
 151     {
 152         return static_cast<int const volatile &>( use_count_ );
 153     }
 154 };
 155
 156 } // namespace detail
 157
 158 } // namespace boost
 159
 160 #endif  // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_CW_X86_HPP_INCLUDED