ceph/src/boost/libs/smart_ptr/include/boost/smart_ptr/detail/sp_counted_base_cw_ppc.hpp

   1 #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_CW_PPC_HPP_INCLUDED
   2 #define BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_CW_PPC_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_ppc.hpp - CodeWarrior on PowerPC
  12 //
  13 //  Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
  14 //  Copyright 2004-2005 Peter Dimov
  15 //
  16 //  Distributed under the Boost Software License, Version 1.0. (See
  17 //  accompanying file LICENSE_1_0.txt or copy at
  18 //  http://www.boost.org/LICENSE_1_0.txt)
  19 //
  20 //
  21 //  Lock-free algorithm by Alexander Terekhov
  22 //
  23 //  Thanks to Ben Hitchings for the #weak + (#shared != 0)
  24 //  formulation
  25 //
  26
  27 #include <boost/detail/sp_typeinfo.hpp>
  28
  29 namespace boost
  30 {
  31
  32 namespace detail
  33 {
  34
  35 inline void atomic_increment( register long * pw )
  36 {
  37     register int a;
  38
  39     asm
  40     {
  41 loop:
  42
  43     lwarx   a, 0, pw
  44     addi    a, a, 1
  45     stwcx.  a, 0, pw
  46     bne-    loop
  47     }
  48 }
  49
  50 inline long atomic_decrement( register long * pw )
  51 {
  52     register int a;
  53
  54     asm
  55     {
  56     sync
  57
  58 loop:
  59
  60     lwarx   a, 0, pw
  61     addi    a, a, -1
  62     stwcx.  a, 0, pw
  63     bne-    loop
  64
  65     isync
  66     }
  67
  68     return a;
  69 }
  70
  71 inline long atomic_conditional_increment( register long * pw )
  72 {
  73     register int a;
  74
  75     asm
  76     {
  77 loop:
  78
  79     lwarx   a, 0, pw
  80     cmpwi   a, 0
  81     beq     store
  82
  83     addi    a, a, 1
  84
  85 store:
  86
  87     stwcx.  a, 0, pw
  88     bne-    loop
  89     }
  90
  91     return a;
  92 }
  93
  94 class sp_counted_base
  95 {
  96 private:
  97
  98     sp_counted_base( sp_counted_base const & );
  99     sp_counted_base & operator= ( sp_counted_base const & );
 100
 101     long use_count_;        // #shared
 102     long weak_count_;       // #weak + (#shared != 0)
 103
 104 public:
 105
 106     sp_counted_base(): use_count_( 1 ), weak_count_( 1 )
 107     {
 108     }
 109
 110     virtual ~sp_counted_base() // nothrow
 111     {
 112     }
 113
 114     // dispose() is called when use_count_ drops to zero, to release
 115     // the resources managed by *this.
 116
 117     virtual void dispose() = 0; // nothrow
 118
 119     // destroy() is called when weak_count_ drops to zero.
 120
 121     virtual void destroy() // nothrow
 122     {
 123         delete this;
 124     }
 125
 126     virtual void * get_deleter( sp_typeinfo const & ti ) = 0;
 127     virtual void * get_untyped_deleter() = 0;
 128
 129     void add_ref_copy()
 130     {
 131         atomic_increment( &use_count_ );
 132     }
 133
 134     bool add_ref_lock() // true on success
 135     {
 136         return atomic_conditional_increment( &use_count_ ) != 0;
 137     }
 138
 139     void release() // nothrow
 140     {
 141         if( atomic_decrement( &use_count_ ) == 0 )
 142         {
 143             dispose();
 144             weak_release();
 145         }
 146     }
 147
 148     void weak_add_ref() // nothrow
 149     {
 150         atomic_increment( &weak_count_ );
 151     }
 152
 153     void weak_release() // nothrow
 154     {
 155         if( atomic_decrement( &weak_count_ ) == 0 )
 156         {
 157             destroy();
 158         }
 159     }
 160
 161     long use_count() const // nothrow
 162     {
 163         return static_cast<long const volatile &>( use_count_ );
 164     }
 165 };
 166
 167 } // namespace detail
 168
 169 } // namespace boost
 170
 171 #endif  // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_CW_PPC_HPP_INCLUDED