trying to get atomic circular fifo

git-svn-id: file:///afs/psi.ch/project/sls_det_software/svn/slsDetectorSoftware@663 951219d9-93cf-4727-9268-0efd64621fa3

slsDetectorSoftware/commonFiles/sls_detector_defs.h

@@ -154,6 +154,7 @@ typedef struct {
   int ymax;   /**< is the roi ymax  (in channel number)*/
 } ROI ;
 
+
 /* /\*  */
 /*     @short structure for a generic integer array */
 /* *\/ */

slsDetectorSoftware/slsDetectorServer/slsDetectorFunctionList.h

@@ -10,6 +10,8 @@
 
 
 
+
+
 /*
 #include <stdio.h>
 #include <stdlib.h>

slsDetectorSoftware/slsReceiver/circularFifo.h

@@ -131,3 +131,111 @@ unsigned int CircularFifo<Element>::increment(unsigned int idx_) const
 }
 
 #endif /* CIRCULARFIFO_H_ */
+
+
+
+
+
+/*
+#ifndef CIRCULARFIFO_H_
+#define CIRCULARFIFO_H_
+
+#include "sls_detector_defs.h"
+
+#include "/usr/include/alsa/atomic.h"
+#include <vector>
+using namespace std;
+
+template<typename Element>
+class CircularFifo {
+public:
+
+	CircularFifo(unsigned int Size) : tail(0), head(0){
+		Capacity = Size + 1;
+		array.resize(Capacity);
+	}
+	virtual ~CircularFifo() {}
+
+	bool push(Element*& item_);
+	bool pop(Element*& item_);
+
+	bool wasEmpty() const;
+	bool wasFull() const;
+	bool isLockFree() const;
+
+private:
+	vector <Element*> array;
+	unsigned int Capacity;
+
+	std::atomic<unsigned int> tail; // input index
+	std::atomic<unsigned int> head; // output index
+
+	unsigned int increment(unsigned int idx_) const;
+};
+
+
+template<typename Element>
+bool CircularFifo<Element>::push(Element*& item_)
+{
+	auto currentTail = tail.load();
+	auto nextTail = increment(currentTail);
+	if(nextTail != head.load())
+	{
+		array[currentTail] = item_;
+		tail.store(nextTail);
+		return true;
+	}
+
+	// queue was full
+	return false;
+}
+
+
+template<typename Element>
+bool CircularFifo<Element>::pop(Element*& item_)
+{
+	const auto currentHead = head.load();
+	if(currentHead == tail.load())
+		return false;  // empty queue
+
+	item_ = array[currentHead];
+	head.store(increment(currentHead));
+	return true;
+}
+
+
+template<typename Element>
+bool CircularFifo<Element>::wasEmpty() const
+{
+	return (head.load() == tail.load());
+}
+
+
+template<typename Element>
+bool CircularFifo<Element>::wasFull() const
+{
+	const auto nextTail = increment(tail.load());
+	return (nextTail == head.load());
+}
+
+template<typename Element>
+bool CircularFifo<Element>::isLockFree() const
+{
+  return (tail.is_lock_free() && head.is_lock_free());
+}
+
+
+template<typename Element>
+unsigned int CircularFifo<Element>::increment(unsigned int idx_) const
+{
+	// increment or wrap
+	// =================
+	//    index++;
+	//    if(index == array.lenght) -> index = 0;
+	//
+	//or as written below:
+	//    index = (index+1) % array.length
+	return (idx_ + 1) % Capacity;
+}
+
+#endif */