Transceiver52M: Set resampling option automatically based on device

Remove the built time resampling selection and link both options.
Move the normal push/pullBuffer() calls back to the base class and
overload them in the inherited resampling class.

USRP2/N2xx devices are the only devices that require resampling so
return that resampling is necessary on the device open(), which is
the point at which the device type will be known.

The GSM transceiver only operates at a whole number multiple of
the GSM rate and doesn't care about the actual device rate and
if resampling is used. Therefore GSM specific portion of the
transceiver should only need to submit the samples-per-symbol
value to the device interface.

Then, the device should be able to determine the appropriate
sample rate (400 ksps or 270.833 ksps) and if resampling is
appropriate.

Signed-off-by: Thomas Tsou <tom@tsou.cc>
diff --git a/Transceiver52M/radioInterface.h b/Transceiver52M/radioInterface.h
index 216cf3e..94d8917 100644
--- a/Transceiver52M/radioInterface.h
+++ b/Transceiver52M/radioInterface.h
@@ -31,7 +31,7 @@
 /** class to interface the transceiver with the USRP */
 class RadioInterface {
 
-private:
+protected:
 
   Thread mAlignRadioServiceLoopThread;	      ///< thread that synchronizes transmit and receive sections
 
@@ -63,6 +63,8 @@
   int mNumARFCNs;
   signalVector *finalVec, *finalVec9;
 
+private:
+
   /** format samples to USRP */ 
   int radioifyVector(signalVector &wVector,
                      float *floatVector,
@@ -73,10 +75,10 @@
   int unRadioifyVector(float *floatVector, signalVector &wVector);
 
   /** push GSM bursts into the transmit buffer */
-  void pushBuffer(void);
+  virtual void pushBuffer(void);
 
   /** pull GSM bursts from the receive buffer */
-  void pullBuffer(void);
+  virtual void pullBuffer(void);
 
 public:
 
@@ -154,3 +156,18 @@
 /** synchronization thread loop */
 void *AlignRadioServiceLoopAdapter(RadioInterface*);
 #endif
+
+class RadioInterfaceResamp : public RadioInterface {
+
+private:
+
+  void pushBuffer();
+  void pullBuffer();
+
+public:
+
+  RadioInterfaceResamp(RadioDevice* wRadio = NULL,
+		       int receiveOffset = 3,
+		       int wSPS = SAMPSPERSYM,
+		       GSM::Time wStartTime = GSM::Time(0));
+};