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/smart_ptr/detail/sp_typeinfo_.hpp>
  29 #include <boost/config.hpp>
  30
  31 namespace boost
  32 {
  33
  34 namespace detail
  35 {
  36
  37 inline int atomic_exchange_and_add( int * pw, int dv )
  38 {
  39     // int r = *pw;
  40     // *pw += dv;
  41     // return r;
  42
  43     asm
  44     {
  45         mov esi, [pw]
  46         mov eax, dv
  47         lock xadd dword ptr [esi], eax
  48     }
  49 }
  50
  51 inline void atomic_increment( int * pw )
  52 {
  53     //atomic_exchange_and_add( pw, 1 );
  54
  55     asm
  56     {
  57         mov esi, [pw]
  58         lock inc dword ptr [esi]
  59     }
  60 }
  61
  62 inline int atomic_conditional_increment( int * pw )
  63 {
  64     // int rv = *pw;
  65     // if( rv != 0 ) ++*pw;
  66     // return rv;
  67
  68     asm
  69     {
  70         mov esi, [pw]
  71         mov eax, dword ptr [esi]
  72     L0:
  73         test eax, eax
  74         je L1
  75         mov ebx, eax
  76         inc ebx
  77         lock cmpxchg dword ptr [esi], ebx
  78         jne L0
  79     L1:
  80     }
  81 }
  82
  83 class BOOST_SYMBOL_VISIBLE sp_counted_base
  84 {
  85 private:
  86
  87     sp_counted_base( sp_counted_base const & );
  88     sp_counted_base & operator= ( sp_counted_base const & );
  89
  90     int use_count_;        // #shared
  91     int weak_count_;       // #weak + (#shared != 0)
  92
  93 public:
  94
  95     sp_counted_base(): use_count_( 1 ), weak_count_( 1 )
  96     {
  97     }
  98
  99     virtual ~sp_counted_base() // nothrow
 100     {
 101     }
 102
 103     // dispose() is called when use_count_ drops to zero, to release
 104     // the resources managed by *this.
 105
 106     virtual void dispose() = 0; // nothrow
 107
 108     // destroy() is called when weak_count_ drops to zero.
 109
 110     virtual void destroy() // nothrow
 111     {
 112         delete this;
 113     }
 114
 115     virtual void * get_deleter( sp_typeinfo_ const & ti ) = 0;
 116     virtual void * get_local_deleter( sp_typeinfo_ const & ti ) = 0;
 117     virtual void * get_untyped_deleter() = 0;
 118
 119     void add_ref_copy()
 120     {
 121         atomic_increment( &use_count_ );
 122     }
 123
 124     bool add_ref_lock() // true on success
 125     {
 126         return atomic_conditional_increment( &use_count_ ) != 0;
 127     }
 128
 129     void release() // nothrow
 130     {
 131         if( atomic_exchange_and_add( &use_count_, -1 ) == 1 )
 132         {
 133             dispose();
 134             weak_release();
 135         }
 136     }
 137
 138     void weak_add_ref() // nothrow
 139     {
 140         atomic_increment( &weak_count_ );
 141     }
 142
 143     void weak_release() // nothrow
 144     {
 145         if( atomic_exchange_and_add( &weak_count_, -1 ) == 1 )
 146         {
 147             destroy();
 148         }
 149     }
 150
 151     long use_count() const // nothrow
 152     {
 153         return static_cast<int const volatile &>( use_count_ );
 154     }
 155 };
 156
 157 } // namespace detail
 158
 159 } // namespace boost
 160
 161 #endif  // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_CW_X86_HPP_INCLUDED