Added lwm_linux.hpp

[SVN r12833]

include/boost/detail/lwm_linux.hpp

@@ -0,0 +1,78 @@
+#ifndef BOOST_DETAIL_LWM_LINUX_HPP_INCLUDED
+#define BOOST_DETAIL_LWM_LINUX_HPP_INCLUDED
+
+#if _MSC_VER >= 1020
+#pragma once
+#endif
+
+//
+//  boost/detail/lwm_linux.hpp
+//
+//  Copyright (c) 2002 Peter Dimov and Multi Media Ltd.
+//
+//  Permission to copy, use, modify, sell and distribute this software
+//  is granted provided this copyright notice appears in all copies.
+//  This software is provided "as is" without express or implied
+//  warranty, and with no claim as to its suitability for any purpose.
+//
+
+#include <asm/atomic.h>
+
+namespace boost
+{
+
+namespace detail
+{
+
+class lightweight_mutex
+{
+private:
+
+    atomic_t a_;
+
+    lightweight_mutex(lightweight_mutex const &);
+    lightweight_mutex & operator=(lightweight_mutex const &);
+
+public:
+
+    lightweight_mutex()
+    {
+        atomic_t a = ATOMIC_INIT(1);
+        a_ = a;
+    }
+
+    class scoped_lock;
+    friend class scoped_lock;
+
+    class scoped_lock
+    {
+    private:
+
+        lightweight_mutex & m_;
+
+        scoped_lock(scoped_lock const &);
+        scoped_lock & operator=(scoped_lock const &);
+
+    public:
+
+        explicit scoped_lock(lightweight_mutex & m): m_(m)
+        {
+            while( !atomic_dec_and_test(&m_.a_) )
+            {
+                atomic_inc(&m_.a_);
+                // sched_yield();
+            }
+        }
+
+        ~scoped_lock()
+        {
+            atomic_inc(&m_.a_);
+        }
+    };
+};
+
+} // namespace detail
+
+} // namespace boost
+
+#endif // #ifndef BOOST_DETAIL_LWM_WIN32_HPP_INCLUDED

include/boost/detail/lwm_win32.hpp

@@ -22,13 +22,10 @@ namespace boost
 namespace detail
 {
 
-// Avoid #including <windows.h>
+// avoid including <windows.h>
 
-namespace win32
-{
 extern "C" __declspec(dllimport) long __stdcall InterlockedExchange(long volatile *, long);
 extern "C" __declspec(dllimport) void __stdcall Sleep(unsigned long);
-}
 
 class lightweight_mutex
 {
@@ -61,14 +58,14 @@ public:
 
         explicit scoped_lock(lightweight_mutex & m): m_(m)
         {
-            while( win32::InterlockedExchange(&m_.l_, 1) ) win32::Sleep(0);
+            while( InterlockedExchange(&m_.l_, 1) ) Sleep(0);
         }
 
         ~scoped_lock()
         {
-            win32::InterlockedExchange(&m_.l_, 0);
+            InterlockedExchange(&m_.l_, 0);
 
-            // Note: adding a win32::Sleep(0) here will make
+            // Note: adding a Sleep(0) here will make
             // the mutex more fair and will increase the overall
             // performance of the application substantially in
             // high contention situations, but will penalize the