Make RingBuffer class template-based

This commit prepares to enlarge the ringbuffer for specific needs (at compile time).
Also, it fixes a spurious include in delay.h

Author: facchinm

Diff for: cores/arduino/RingBuffer.cpp

@@ -16,6 +16,8 @@
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
 
+#ifdef __cplusplus
+
 #ifndef _RING_BUFFER_
 #define _RING_BUFFER_
 
@@ -27,25 +29,114 @@
 // location from which to read.
 #define SERIAL_BUFFER_SIZE 64
 
-class RingBuffer
+template <int N>
+class RingBufferN
 {
   public:
-    uint8_t _aucBuffer[SERIAL_BUFFER_SIZE] ;
+    uint8_t _aucBuffer[N] ;
     int _iHead ;
     int _iTail ;
 
   public:
-    RingBuffer( void ) ;
+    RingBufferN( void ) ;
     void store_char( uint8_t c ) ;
-	void clear();
-	int read_char();
-	int available();
-	int availableForStore();
-	int peek();
-	bool isFull();
+    void clear();
+    int read_char();
+    int available();
+    int availableForStore();
+    int peek();
+    bool isFull();
 
   private:
-	int nextIndex(int index);
-} ;
+    int nextIndex(int index);
+};
+
+typedef RingBufferN<SERIAL_BUFFER_SIZE> RingBuffer;
+
+
+template <int N>
+RingBufferN<N>::RingBufferN( void )
+{
+    memset( _aucBuffer, 0, N ) ;
+    clear();
+}
+
+template <int N>
+void RingBufferN<N>::store_char( uint8_t c )
+{
+  int i = nextIndex(_iHead);
+
+  // if we should be storing the received character into the location
+  // just before the tail (meaning that the head would advance to the
+  // current location of the tail), we're about to overflow the buffer
+  // and so we don't write the character or advance the head.
+  if ( i != _iTail )
+  {
+    _aucBuffer[_iHead] = c ;
+    _iHead = i ;
+  }
+}
+
+template <int N>
+void RingBufferN<N>::clear()
+{
+  _iHead = 0;
+  _iTail = 0;
+}
+
+template <int N>
+int RingBufferN<N>::read_char()
+{
+  if(_iTail == _iHead)
+    return -1;
+
+  uint8_t value = _aucBuffer[_iTail];
+  _iTail = nextIndex(_iTail);
+
+  return value;
+}
+
+template <int N>
+int RingBufferN<N>::available()
+{
+  int delta = _iHead - _iTail;
+
+  if(delta < 0)
+    return N + delta;
+  else
+    return delta;
+}
+
+template <int N>
+int RingBufferN<N>::availableForStore()
+{
+  if (_iHead >= _iTail)
+    return N - 1 - _iHead + _iTail;
+  else
+    return _iTail - _iHead - 1;
+}
+
+template <int N>
+int RingBufferN<N>::peek()
+{
+  if(_iTail == _iHead)
+    return -1;
+
+  return _aucBuffer[_iTail];
+}
+
+template <int N>
+int RingBufferN<N>::nextIndex(int index)
+{
+  return (uint32_t)(index + 1) % N;
+}
+
+template <int N>
+bool RingBufferN<N>::isFull()
+{
+  return (nextIndex(_iHead) == _iTail);
+}
 
 #endif /* _RING_BUFFER_ */
+
+#endif /* __cplusplus */

Diff for: cores/arduino/RingBuffer.h

@@ -19,13 +19,13 @@
 #ifndef _DELAY_
 #define _DELAY_
 
+#include <stdint.h>
+#include "variant.h"
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-#include <stdint.h>
-#include "variant.h"
-
 /**
  * \brief Returns the number of milliseconds since the Arduino board began running the current program.
  *