From b53db4c792444b4b3acea377a1fe2381b8eec4d9 Mon Sep 17 00:00:00 2001
From: miha_vitorovic <unknown>
Date: Thu, 11 Nov 2010 14:03:53 +0100
Subject: [PATCH] GrowingCircularBuffer added and tested.

---
 configure/RELEASE                             |   2 +-
 pvAccessApp/testUtils/Makefile                |   3 +
 .../testUtils/growingCircularBufferTest.cpp   |  50 ++++++
 pvAccessApp/utils/Makefile                    |   3 +-
 pvAccessApp/utils/growingCircularBuffer.h     | 152 ++++++++++++++++++
 5 files changed, 208 insertions(+), 2 deletions(-)
 create mode 100644 pvAccessApp/testUtils/growingCircularBufferTest.cpp
 create mode 100644 pvAccessApp/utils/growingCircularBuffer.h

diff --git a/configure/RELEASE b/configure/RELEASE
index 4a040e9..119108e 100644
--- a/configure/RELEASE
+++ b/configure/RELEASE
@@ -25,7 +25,7 @@ TEMPLATE_TOP=$(EPICS_BASE)/templates/makeBaseApp/top
 #SNCSEQ=$(EPICS_BASE)/../modules/soft/seq
 
 # EPICS_BASE usually appears last so other apps can override stuff:
-EPICS_BASE=/Users/msekoranja/Work/EPICS/base-3.14.11
+EPICS_BASE=/opt/epics/base
 
 # Set RULES here if you want to take build rules from somewhere
 # other than EPICS_BASE:
diff --git a/pvAccessApp/testUtils/Makefile b/pvAccessApp/testUtils/Makefile
index 58d8f96..0a5f1d9 100644
--- a/pvAccessApp/testUtils/Makefile
+++ b/pvAccessApp/testUtils/Makefile
@@ -14,6 +14,9 @@ PROD_HOST += arrayFIFOTest
 arrayFIFOTest_SRCS += arrayFIFOTest.cpp
 arrayFIFOTest_LIBS += pvAccUtils Com
 
+PROD_HOST += growingCircularBufferTest
+growingCircularBufferTest_SRCS += growingCircularBufferTest.cpp
+growingCircularBufferTest_LIBS += pvAccUtils Com
 
 include $(TOP)/configure/RULES
 #----------------------------------------
diff --git a/pvAccessApp/testUtils/growingCircularBufferTest.cpp b/pvAccessApp/testUtils/growingCircularBufferTest.cpp
new file mode 100644
index 0000000..933a006
--- /dev/null
+++ b/pvAccessApp/testUtils/growingCircularBufferTest.cpp
@@ -0,0 +1,50 @@
+/*
+ * growingCircularBufferTest.cpp
+ *
+ *  Created on: Nov 11, 2010
+ *      Author: Miha Vitorovic
+ */
+
+#include "growingCircularBuffer.h"
+
+#include <iostream>
+#include <epicsAssert.h>
+
+using namespace epics::pvAccess;
+using std::cout;
+using std::endl;
+
+const int CAPACITY = 10;
+
+int main(int argc, char *argv[]) {
+    GrowingCircularBuffer<int> cb(CAPACITY);
+
+    cout<<"Testing circular buffer."<<endl;
+
+    assert(cb.capacity()==CAPACITY);
+    assert(cb.size()==0);
+
+    // insert, get test
+    bool first = cb.insert(1);
+    assert(cb.size()==1);
+    assert(cb.extract()==1);
+    assert(first);
+    assert(cb.size()==0);
+
+    for(int i = 0; i<2*CAPACITY; i++) {
+        first = cb.insert(i);
+        assert(cb.size()==i+1);
+        assert((cb.size() == 1)==first);
+    }
+    assert(cb.size()==2*CAPACITY);
+
+    for(int i = 0; i<2*CAPACITY; i++) {
+        assert(cb.extract()==i);
+        assert(cb.size()==2*CAPACITY-i-1);
+    }
+    assert(cb.size()==0);
+
+    cout<<"\nPASSED!\n";
+    return 0;
+
+}
diff --git a/pvAccessApp/utils/Makefile b/pvAccessApp/utils/Makefile
index 363fa30..21dbeef 100644
--- a/pvAccessApp/utils/Makefile
+++ b/pvAccessApp/utils/Makefile
@@ -5,13 +5,14 @@ include $(TOP)/configure/CONFIG
 INC += hexDump.h
 INC += wildcharMatcher.h
 INC += arrayFIFO.h
+INC += growingCircularBuffer.h
 
 LIBSRCS += hexDump.cpp
 LIBSRCS += wildcharMatcher.cpp
 
 LIBRARY = pvAccUtils
 
-#pvAccess_LIBS += Com
+#pvAccUtils_LIBS += Com
 
 include $(TOP)/configure/RULES
 #----------------------------------------
diff --git a/pvAccessApp/utils/growingCircularBuffer.h b/pvAccessApp/utils/growingCircularBuffer.h
new file mode 100644
index 0000000..82f2a1c
--- /dev/null
+++ b/pvAccessApp/utils/growingCircularBuffer.h
@@ -0,0 +1,152 @@
+/*
+ * growingCircularBuffer.h
+ *
+ *  Created on: Nov 11, 2010
+ *      Author: Miha Vitorovic
+ */
+
+#ifndef GROWINGCIRCULARBUFFER_H_
+#define GROWINGCIRCULARBUFFER_H_
+
+#include <epicsException.h>
+
+using epics::pvData::BaseException;
+
+namespace epics {
+    namespace pvAccess {
+
+        /**
+         * Implementation of circular FIFO unbouded buffer.
+         * Instance is not thread safe.
+         * @author Miha Vitorovic
+         */
+        template<class T>
+        class GrowingCircularBuffer {
+        public:
+
+            /**
+             * Create a GrowingCircularBuffer with the given capacity.
+             **/
+            GrowingCircularBuffer(size_t capacity = 16) :
+                _takePointer(0), _putPointer(0), _count(0), _size(capacity),
+                        _elements(new T[capacity]) {
+            }
+
+            ~GrowingCircularBuffer() {
+                delete _elements;
+            }
+
+            /**
+             * Get number of elements in the buffer.
+             * @return number of elements in the buffer.
+             */
+            inline size_t size() {
+                return _count;
+            }
+
+            /**
+             * Get current buffer capacity.
+             * @return buffer current capacity.
+             */
+            inline size_t capacity() {
+                return _size;
+            }
+
+            /**
+             * Insert a new element in to the buffer.
+             * If buffer full the buffer is doubled.
+             *
+             * @param x element to insert.
+             * @return <code>true</code> if first element.
+             */
+            bool insert(const T x);
+
+            /**
+             * Extract the oldest element from the buffer.
+             * @return the oldest element from the buffer.
+             */
+            T extract();
+
+        private:
+            /**
+             * Array (circular buffer) of elements.
+             */
+            T* _elements;
+
+            /**
+             * Take (read) pointer.
+             */
+            size_t _takePointer;
+
+            /**
+             * Put (write) pointer.
+             */
+            size_t _putPointer;
+
+            /**
+             * Number of elements in the buffer.
+             */
+            size_t _count;
+
+            size_t _size;
+
+            void arraycopy(T* src, size_t srcPos, T* dest, size_t destPos,
+                    size_t length);
+        };
+
+        /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+         * g++ requires template definition inside a header file.
+         * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+        template<class T>
+        void GrowingCircularBuffer<T>::arraycopy(T* src, size_t srcPos, T* dest,
+                size_t destPos, size_t length) {
+            if(srcPos<destPos) // this takes care of same-buffer copy
+                for(int i = length-1; i>=0; i--)
+                    dest[destPos+i] = src[srcPos+i];
+            else
+                for(size_t i = 0; i<length; i++)
+                    dest[destPos++] = src[srcPos++];
+        }
+
+        template<class T>
+        bool GrowingCircularBuffer<T>::insert(const T x) {
+            if (_count == _size)
+            {
+                // we are full, grow by factor 2
+                T* newElements = new T[_size * 2];
+
+                // invariant: _takePointer < _size
+                size_t split = _size - _takePointer;
+                if (split > 0)
+                    arraycopy(_elements, _takePointer, newElements, 0, split);
+                if (_takePointer != 0)
+                    arraycopy(_elements, 0, newElements, split, _putPointer);
+
+                _takePointer = 0;
+                _putPointer = _size;
+                _size *= 2;
+                delete _elements;
+                _elements = newElements;
+            }
+            _count++;
+
+            _elements[_putPointer] = x;
+            if (++_putPointer >= _size) _putPointer = 0;
+            return _count == 1;
+
+        }
+
+        template<class T>
+        T GrowingCircularBuffer<T>::extract() {
+            if(_count==0) THROW_BASE_EXCEPTION("Buffer empty.");
+
+            _count--;
+            T old = _elements[_takePointer];
+            if(++_takePointer>=_size) _takePointer = 0;
+            return old;
+        }
+
+    }
+}
+#endif /* GROWINGCIRCULARBUFFER_H_ */