From b51965dddbed68f23c5e8c169c23c794313ce5f6 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Tue, 28 Jun 2011 17:17:23 +0200
Subject: Add boost subset as an implementation detail

---
 .../smart_ptr/detail/sp_counted_base_gcc_x86.hpp   | 173 +++++++++++++++++++++
 1 file changed, 173 insertions(+)
 create mode 100644 cutl/details/boost/smart_ptr/detail/sp_counted_base_gcc_x86.hpp

(limited to 'cutl/details/boost/smart_ptr/detail/sp_counted_base_gcc_x86.hpp')

diff --git a/cutl/details/boost/smart_ptr/detail/sp_counted_base_gcc_x86.hpp b/cutl/details/boost/smart_ptr/detail/sp_counted_base_gcc_x86.hpp
new file mode 100644
index 0000000..68f0646
--- /dev/null
+++ b/cutl/details/boost/smart_ptr/detail/sp_counted_base_gcc_x86.hpp
@@ -0,0 +1,173 @@
+#ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_X86_HPP_INCLUDED
+#define BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_X86_HPP_INCLUDED
+
+// MS compatible compilers support #pragma once
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1020)
+# pragma once
+#endif
+
+//
+//  detail/sp_counted_base_gcc_x86.hpp - g++ on 486+ or AMD64
+//
+//  Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
+//  Copyright 2004-2005 Peter Dimov
+//
+//  Distributed under the Boost Software License, Version 1.0. (See
+//  accompanying file LICENSE_1_0.txt or copy at
+//  http://www.boost.org/LICENSE_1_0.txt)
+//
+//
+//  Lock-free algorithm by Alexander Terekhov
+//
+//  Thanks to Ben Hitchings for the #weak + (#shared != 0)
+//  formulation
+//
+
+#include <cutl/details/boost/detail/sp_typeinfo.hpp>
+
+namespace cutl_details_boost
+{
+
+namespace detail
+{
+
+inline int atomic_exchange_and_add( int * pw, int dv )
+{
+    // int r = *pw;
+    // *pw += dv;
+    // return r;
+
+    int r;
+
+    __asm__ __volatile__
+    (
+        "lock\n\t"
+        "xadd %1, %0":
+        "=m"( *pw ), "=r"( r ): // outputs (%0, %1)
+        "m"( *pw ), "1"( dv ): // inputs (%2, %3 == %1)
+        "memory", "cc" // clobbers
+    );
+
+    return r;
+}
+
+inline void atomic_increment( int * pw )
+{
+    //atomic_exchange_and_add( pw, 1 );
+
+    __asm__
+    (
+        "lock\n\t"
+        "incl %0":
+        "=m"( *pw ): // output (%0)
+        "m"( *pw ): // input (%1)
+        "cc" // clobbers
+    );
+}
+
+inline int atomic_conditional_increment( int * pw )
+{
+    // int rv = *pw;
+    // if( rv != 0 ) ++*pw;
+    // return rv;
+
+    int rv, tmp;
+
+    __asm__
+    (
+        "movl %0, %%eax\n\t"
+        "0:\n\t"
+        "test %%eax, %%eax\n\t"
+        "je 1f\n\t"
+        "movl %%eax, %2\n\t"
+        "incl %2\n\t"
+        "lock\n\t"
+        "cmpxchgl %2, %0\n\t"
+        "jne 0b\n\t"
+        "1:":
+        "=m"( *pw ), "=&a"( rv ), "=&r"( tmp ): // outputs (%0, %1, %2)
+        "m"( *pw ): // input (%3)
+        "cc" // clobbers
+    );
+
+    return rv;
+}
+
+class sp_counted_base
+{
+private:
+
+    sp_counted_base( sp_counted_base const & );
+    sp_counted_base & operator= ( sp_counted_base const & );
+
+    int use_count_;        // #shared
+    int weak_count_;       // #weak + (#shared != 0)
+
+public:
+
+    sp_counted_base(): use_count_( 1 ), weak_count_( 1 )
+    {
+    }
+
+    virtual ~sp_counted_base() // nothrow
+    {
+    }
+
+    // dispose() is called when use_count_ drops to zero, to release
+    // the resources managed by *this.
+
+    virtual void dispose() = 0; // nothrow
+
+    // destroy() is called when weak_count_ drops to zero.
+
+    virtual void destroy() // nothrow
+    {
+        delete this;
+    }
+
+    virtual void * get_deleter( sp_typeinfo const & ti ) = 0;
+
+    void add_ref_copy()
+    {
+        atomic_increment( &use_count_ );
+    }
+
+    bool add_ref_lock() // true on success
+    {
+        return atomic_conditional_increment( &use_count_ ) != 0;
+    }
+
+    void release() // nothrow
+    {
+        if( atomic_exchange_and_add( &use_count_, -1 ) == 1 )
+        {
+            dispose();
+            weak_release();
+        }
+    }
+
+    void weak_add_ref() // nothrow
+    {
+        atomic_increment( &weak_count_ );
+    }
+
+    void weak_release() // nothrow
+    {
+        if( atomic_exchange_and_add( &weak_count_, -1 ) == 1 )
+        {
+            destroy();
+        }
+    }
+
+    long use_count() const // nothrow
+    {
+        return static_cast<int const volatile &>( use_count_ );
+    }
+};
+
+} // namespace detail
+
+} // namespace cutl_details_boost
+
+#endif  // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_X86_HPP_INCLUDED
-- 
cgit v1.1