From 6a51e31a30055d3bb11d38c5cffb1de99396e8d8 Mon Sep 17 00:00:00 2001
From: Matej Sekoranja <unknown>
Date: Thu, 6 Oct 2011 15:47:14 +0200
Subject: [PATCH] fixed AtomicBoolen

---
 pvAccessApp/remote/blockingTCP.h | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/pvAccessApp/remote/blockingTCP.h b/pvAccessApp/remote/blockingTCP.h
index 69d2bfd..60a66ea 100644
--- a/pvAccessApp/remote/blockingTCP.h
+++ b/pvAccessApp/remote/blockingTCP.h
@@ -44,18 +44,21 @@ struct null_deleter
     void operator()(void const *) const {}
 };
 
+// standard performance on set/clear, use of tr1::shared_ptr lock-free counter for get
+// alternative is to use boost::atomic
 class AtomicBoolean
 {
     public:
-        AtomicBoolean() {};
-        
-        void set() { counter.reset(static_cast<void*>(0), null_deleter()); }
-        void clear() { counter.reset(); }
+        AtomicBoolean() : counter(static_cast<void*>(0), null_deleter()) {};
 
-        bool get() { return counter.use_count(); }
-        
+        void set() { mutex.lock(); setp = counter; mutex.unlock(); }
+        void clear() { mutex.lock(); setp.reset(); mutex.unlock(); }
+
+        bool get() const { return counter.use_count() == 2; }
     private:
         std::tr1::shared_ptr<void> counter;
+        std::tr1::shared_ptr<void> setp;
+        epics::pvData::Mutex mutex;
 };