initial files checked in

libraries/Misc/circular_buffer.h

@@ -0,0 +1,113 @@
+#ifndef circ_buffer_h
+#define circ_buffer_h
+
+#include <stdlib.h>
+
+/// <summary>
+/// This class allows a fixed size circular buffer.
+/// When push_back is called, oldest data is overwritten.
+/// Does not use any dynamic allocators.
+/// </summary>
+template <class ItemType, int elementCnt> class circular_buffer
+{
+private:
+  ItemType m_arr[elementCnt];
+  int m_writePos;
+  int m_size;
+
+  void advanceWritePos()
+  {
+    if(m_size < elementCnt)
+    {
+      m_size++;
+    }
+
+    m_writePos++;
+    if(m_writePos >= elementCnt)
+    {
+      m_writePos = 0;
+    }
+  }
+
+  circular_buffer(const circular_buffer<ItemType, elementCnt>& rhs);
+public:
+  circular_buffer()
+  {
+    clear();
+  }
+  
+  void operator=(const circular_buffer<ItemType, elementCnt>& rhs)
+  {
+    memcpy(m_arr, rhs.m_arr, sizeof(m_arr));
+    m_size = rhs.m_size;
+    m_writePos = rhs.m_writePos;
+  }
+
+  void push_back(const ItemType& item)
+  {
+    m_arr[m_writePos] = item;
+    advanceWritePos();
+  }
+  
+  void clear()
+  {
+    memset(m_arr,0,sizeof(m_arr));
+    m_size = m_writePos = 0;
+  }
+
+  void sort()
+  {
+    if (size() < 2)
+      return;
+    
+    bool swapped;
+    do
+    {
+      swapped = false;
+      for(int ix=0; ix<size()-1; ix++)
+      {
+        if(at(ix) > at(ix+1))
+        {
+          ItemType tmp = at(ix);
+          at(ix) = at(ix+1);
+          at(ix+1) = tmp;
+          swapped = true;
+        }
+      }
+
+    }while(swapped);
+  }
+
+  int size() const { return m_size; }
+  bool isFull() const { return size() == elementCnt; }
+  ItemType& operator[](int pos) {return at(pos);}
+
+  ItemType& at(int pos) 
+  {
+    if(m_size < elementCnt)
+    {
+      return m_arr[pos];
+    }
+
+    int readPos = m_writePos + pos;
+    if(readPos >= elementCnt)
+    {
+      readPos -= elementCnt;
+    }
+
+    return m_arr[readPos];
+  }
+
+#if _DEBUG_ENABLED
+  void print() 
+  {
+    printf("---\n");
+    for(int i=0; i<size(); i++)
+    {
+      printf("%d = %d\n", i, at(i));
+    }
+  }
+#endif
+};
+
+#endif //circ_buffer_h