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

   1 #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_SPARC_HPP_INCLUDED
   2 #define BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_SPARC_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 //  detail/sp_counted_base_gcc_sparc.hpp - g++ on Sparc V8+
  11 //
  12 //  Copyright (c) 2006 Piotr Wyderski
  13 //  Copyright (c) 2006 Tomas Puverle
  14 //  Copyright (c) 2006 Peter Dimov
  15 //
  16 //  Distributed under the Boost Software License, Version 1.0.
  17 //  See accompanying file LICENSE_1_0.txt or copy at
  18 //  http://www.boost.org/LICENSE_1_0.txt
  19 //
  20 //  Thanks to Michael van der Westhuizen
  21
  22 #include <boost/smart_ptr/detail/sp_typeinfo_.hpp>
  23 #include <boost/config.hpp>
  24 #include <inttypes.h> // int32_t
  25
  26 namespace boost
  27 {
  28
  29 namespace detail
  30 {
  31
  32 inline int32_t compare_and_swap( int32_t * dest_, int32_t compare_, int32_t swap_ )
  33 {
  34     __asm__ __volatile__( "cas [%1], %2, %0"
  35                         : "+r" (swap_)
  36                         : "r" (dest_), "r" (compare_)
  37                         : "memory" );
  38
  39     return swap_;
  40 }
  41
  42 inline int32_t atomic_fetch_and_add( int32_t * pw, int32_t dv )
  43 {
  44     // long r = *pw;
  45     // *pw += dv;
  46     // return r;
  47
  48     for( ;; )
  49     {
  50         int32_t r = *pw;
  51
  52         if( __builtin_expect((compare_and_swap(pw, r, r + dv) == r), 1) )
  53         {
  54             return r;
  55         }
  56     }
  57 }
  58
  59 inline void atomic_increment( int32_t * pw )
  60 {
  61     atomic_fetch_and_add( pw, 1 );
  62 }
  63
  64 inline int32_t atomic_decrement( int32_t * pw )
  65 {
  66     return atomic_fetch_and_add( pw, -1 );
  67 }
  68
  69 inline int32_t atomic_conditional_increment( int32_t * pw )
  70 {
  71     // long r = *pw;
  72     // if( r != 0 ) ++*pw;
  73     // return r;
  74
  75     for( ;; )
  76     {
  77         int32_t r = *pw;
  78
  79         if( r == 0 )
  80         {
  81             return r;
  82         }
  83
  84         if( __builtin_expect( ( compare_and_swap( pw, r, r + 1 ) == r ), 1 ) )
  85         {
  86             return r;
  87         }
  88     }
  89 }
  90
  91 class BOOST_SYMBOL_VISIBLE sp_counted_base
  92 {
  93 private:
  94
  95     sp_counted_base( sp_counted_base const & );
  96     sp_counted_base & operator= ( sp_counted_base const & );
  97
  98     int32_t use_count_;        // #shared
  99     int32_t weak_count_;       // #weak + (#shared != 0)
 100
 101 public:
 102
 103     sp_counted_base(): use_count_( 1 ), weak_count_( 1 )
 104     {
 105     }
 106
 107     virtual ~sp_counted_base() // nothrow
 108     {
 109     }
 110
 111     // dispose() is called when use_count_ drops to zero, to release
 112     // the resources managed by *this.
 113
 114     virtual void dispose() = 0; // nothrow
 115
 116     // destroy() is called when weak_count_ drops to zero.
 117
 118     virtual void destroy() // nothrow
 119     {
 120         delete this;
 121     }
 122
 123     virtual void * get_deleter( sp_typeinfo_ const & ti ) = 0;
 124     virtual void * get_local_deleter( sp_typeinfo_ const & ti ) = 0;
 125     virtual void * get_untyped_deleter() = 0;
 126
 127     void add_ref_copy()
 128     {
 129         atomic_increment( &use_count_ );
 130     }
 131
 132     bool add_ref_lock() // true on success
 133     {
 134         return atomic_conditional_increment( &use_count_ ) != 0;
 135     }
 136
 137     void release() // nothrow
 138     {
 139         if( atomic_decrement( &use_count_ ) == 1 )
 140         {
 141             dispose();
 142             weak_release();
 143         }
 144     }
 145
 146     void weak_add_ref() // nothrow
 147     {
 148         atomic_increment( &weak_count_ );
 149     }
 150
 151     void weak_release() // nothrow
 152     {
 153         if( atomic_decrement( &weak_count_ ) == 1 )
 154         {
 155             destroy();
 156         }
 157     }
 158
 159     long use_count() const // nothrow
 160     {
 161         return const_cast< int32_t const volatile & >( use_count_ );
 162     }
 163 };
 164
 165 } // namespace detail
 166
 167 } // namespace boost
 168
 169 #endif  // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_SPARC_HPP_INCLUDED