smart_ptr/detail/sp_counted_base_gcc_sparc.hpp

0001 #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_SPARC_HPP_INCLUDED
0002 #define BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_SPARC_HPP_INCLUDED
0003
0004 // MS compatible compilers support #pragma once
0005
0006 #if defined(_MSC_VER) && (_MSC_VER >= 1020)
0007 # pragma once
0008 #endif
0009
0010 //  detail/sp_counted_base_gcc_sparc.hpp - g++ on Sparc V8+
0011 //
0012 //  Copyright (c) 2006 Piotr Wyderski
0013 //  Copyright (c) 2006 Tomas Puverle
0014 //  Copyright (c) 2006 Peter Dimov
0015 //
0016 //  Distributed under the Boost Software License, Version 1.0.
0017 //  See accompanying file LICENSE_1_0.txt or copy at
0018 //  http://www.boost.org/LICENSE_1_0.txt
0019 //
0020 //  Thanks to Michael van der Westhuizen
0021
0022 #include <boost/smart_ptr/detail/sp_typeinfo_.hpp>
0023 #include <boost/smart_ptr/detail/sp_obsolete.hpp>
0024 #include <boost/config.hpp>
0025 #include <inttypes.h> // int32_t
0026
0027 #if defined(BOOST_SP_REPORT_IMPLEMENTATION)
0028
0029 #include <boost/config/pragma_message.hpp>
0030 BOOST_PRAGMA_MESSAGE("Using g++/Sparc sp_counted_base")
0031
0032 #endif
0033
0034 BOOST_SP_OBSOLETE()
0035
0036 namespace boost
0037 {
0038
0039 namespace detail
0040 {
0041
0042 inline int32_t compare_and_swap( int32_t * dest_, int32_t compare_, int32_t swap_ )
0043 {
0044     __asm__ __volatile__( "cas [%1], %2, %0"
0045                         : "+r" (swap_)
0046                         : "r" (dest_), "r" (compare_)
0047                         : "memory" );
0048
0049     return swap_;
0050 }
0051
0052 inline int32_t atomic_fetch_and_add( int32_t * pw, int32_t dv )
0053 {
0054     // long r = *pw;
0055     // *pw += dv;
0056     // return r;
0057
0058     for( ;; )
0059     {
0060         int32_t r = *pw;
0061
0062         if( __builtin_expect((compare_and_swap(pw, r, r + dv) == r), 1) )
0063         {
0064             return r;
0065         }
0066     }
0067 }
0068
0069 inline void atomic_increment( int32_t * pw )
0070 {
0071     atomic_fetch_and_add( pw, 1 );
0072 }
0073
0074 inline int32_t atomic_decrement( int32_t * pw )
0075 {
0076     return atomic_fetch_and_add( pw, -1 );
0077 }
0078
0079 inline int32_t atomic_conditional_increment( int32_t * pw )
0080 {
0081     // long r = *pw;
0082     // if( r != 0 ) ++*pw;
0083     // return r;
0084
0085     for( ;; )
0086     {
0087         int32_t r = *pw;
0088
0089         if( r == 0 )
0090         {
0091             return r;
0092         }
0093
0094         if( __builtin_expect( ( compare_and_swap( pw, r, r + 1 ) == r ), 1 ) )
0095         {
0096             return r;
0097         }
0098     }
0099 }
0100
0101 class BOOST_SYMBOL_VISIBLE sp_counted_base
0102 {
0103 private:
0104
0105     sp_counted_base( sp_counted_base const & );
0106     sp_counted_base & operator= ( sp_counted_base const & );
0107
0108     int32_t use_count_;        // #shared
0109     int32_t weak_count_;       // #weak + (#shared != 0)
0110
0111 public:
0112
0113     sp_counted_base(): use_count_( 1 ), weak_count_( 1 )
0114     {
0115     }
0116
0117     virtual ~sp_counted_base() // nothrow
0118     {
0119     }
0120
0121     // dispose() is called when use_count_ drops to zero, to release
0122     // the resources managed by *this.
0123
0124     virtual void dispose() = 0; // nothrow
0125
0126     // destroy() is called when weak_count_ drops to zero.
0127
0128     virtual void destroy() // nothrow
0129     {
0130         delete this;
0131     }
0132
0133     virtual void * get_deleter( sp_typeinfo_ const & ti ) = 0;
0134     virtual void * get_local_deleter( sp_typeinfo_ const & ti ) = 0;
0135     virtual void * get_untyped_deleter() = 0;
0136
0137     void add_ref_copy()
0138     {
0139         atomic_increment( &use_count_ );
0140     }
0141
0142     bool add_ref_lock() // true on success
0143     {
0144         return atomic_conditional_increment( &use_count_ ) != 0;
0145     }
0146
0147     void release() // nothrow
0148     {
0149         if( atomic_decrement( &use_count_ ) == 1 )
0150         {
0151             dispose();
0152             weak_release();
0153         }
0154     }
0155
0156     void weak_add_ref() // nothrow
0157     {
0158         atomic_increment( &weak_count_ );
0159     }
0160
0161     void weak_release() // nothrow
0162     {
0163         if( atomic_decrement( &weak_count_ ) == 1 )
0164         {
0165             destroy();
0166         }
0167     }
0168
0169     long use_count() const // nothrow
0170     {
0171         return const_cast< int32_t const volatile & >( use_count_ );
0172     }
0173 };
0174
0175 } // namespace detail
0176
0177 } // namespace boost
0178
0179 #endif  // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_SPARC_HPP_INCLUDED