ceph/src/boost/boost/smart_ptr/detail/sp_counted_base_snc_ps3.hpp

   1 #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_SNC_PS3_HPP_INCLUDED
   2 #define BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_SNC_PS3_HPP_INCLUDED
   3
   4 // MS compatible compilers support #pragma once
   5 #if defined(_MSC_VER) && (_MSC_VER >= 1020)
   6 # pragma once
   7 #endif
   8
   9 //  detail/sp_counted_base_gcc_sparc.hpp - g++ on Sparc V8+
  10 //
  11 //  Copyright (c) 2006 Piotr Wyderski
  12 //  Copyright (c) 2006 Tomas Puverle
  13 //  Copyright (c) 2006 Peter Dimov
  14 //  Copyright (c) 2011 Emil Dotchevski
  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/detail/sp_typeinfo.hpp>
  23 #include <inttypes.h> // uint32_t
  24
  25 namespace boost
  26 {
  27
  28 namespace detail
  29 {
  30
  31 inline uint32_t compare_and_swap( uint32_t * dest_, uint32_t compare_, uint32_t swap_ )
  32 {
  33     return __builtin_cellAtomicCompareAndSwap32(dest_,compare_,swap_);
  34 }
  35
  36 inline uint32_t atomic_fetch_and_add( uint32_t * pw, uint32_t dv )
  37 {
  38     // long r = *pw;
  39     // *pw += dv;
  40     // return r;
  41
  42     for( ;; )
  43     {
  44         uint32_t r = *pw;
  45
  46         if( __builtin_expect((compare_and_swap(pw, r, r + dv) == r), 1) )
  47         {
  48             return r;
  49         }
  50     }
  51 }
  52
  53 inline void atomic_increment( uint32_t * pw )
  54 {
  55     (void) __builtin_cellAtomicIncr32( pw );
  56 }
  57
  58 inline uint32_t atomic_decrement( uint32_t * pw )
  59 {
  60     return __builtin_cellAtomicDecr32( pw );
  61 }
  62
  63 inline uint32_t atomic_conditional_increment( uint32_t * pw )
  64 {
  65     // long r = *pw;
  66     // if( r != 0 ) ++*pw;
  67     // return r;
  68
  69     for( ;; )
  70     {
  71         uint32_t r = *pw;
  72
  73         if( r == 0 )
  74         {
  75             return r;
  76         }
  77
  78         if( __builtin_expect( ( compare_and_swap( pw, r, r + 1 ) == r ), 1 ) )
  79         {
  80             return r;
  81         }
  82     }
  83 }
  84
  85 class sp_counted_base
  86 {
  87 private:
  88
  89     sp_counted_base( sp_counted_base const & );
  90     sp_counted_base & operator= ( sp_counted_base const & );
  91
  92     uint32_t use_count_;        // #shared
  93     uint32_t weak_count_;       // #weak + (#shared != 0)
  94
  95 public:
  96
  97     sp_counted_base(): use_count_( 1 ), weak_count_( 1 )
  98     {
  99     }
 100
 101     virtual ~sp_counted_base() // nothrow
 102     {
 103     }
 104
 105     // dispose() is called when use_count_ drops to zero, to release
 106     // the resources managed by *this.
 107
 108     virtual void dispose() = 0; // nothrow
 109
 110     // destroy() is called when weak_count_ drops to zero.
 111
 112     virtual void destroy() // nothrow
 113     {
 114         delete this;
 115     }
 116
 117     virtual void * get_deleter( sp_typeinfo const & ti ) = 0;
 118     virtual void * get_local_deleter( sp_typeinfo const & ti ) = 0;
 119     virtual void * get_untyped_deleter() = 0;
 120
 121     void add_ref_copy()
 122     {
 123         atomic_increment( &use_count_ );
 124     }
 125
 126     bool add_ref_lock() // true on success
 127     {
 128         return atomic_conditional_increment( &use_count_ ) != 0;
 129     }
 130
 131     void release() // nothrow
 132     {
 133         if( atomic_decrement( &use_count_ ) == 1 )
 134         {
 135             dispose();
 136             weak_release();
 137         }
 138     }
 139
 140     void weak_add_ref() // nothrow
 141     {
 142         atomic_increment( &weak_count_ );
 143     }
 144
 145     void weak_release() // nothrow
 146     {
 147         if( atomic_decrement( &weak_count_ ) == 1 )
 148         {
 149             destroy();
 150         }
 151     }
 152
 153     long use_count() const // nothrow
 154     {
 155         return const_cast< uint32_t const volatile & >( use_count_ );
 156     }
 157 };
 158
 159 } // namespace detail
 160
 161 } // namespace boost
 162
 163 #endif  // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_SNC_PS3_HPP_INCLUDED