Tx ph.2: restored ancient interpolator

sdrbase/dsp/interpolator.h

@@ -35,7 +35,7 @@ public:
 		return true;
 	}
 
-	// interpolation works nearly the same way
+	// interpolation works nearly the same way // TODO: remove when original is used
 	bool interpolate(Real *distance, const Complex& next, Complex* result)
 	{
         *distance -= 1.0;
@@ -54,6 +54,28 @@ public:
         }
 	}
 
+	// original interpolator
+	bool interpolate(Real* distance, const Complex& next, bool* consumed, Complex* result)
+	{
+		while(*distance >= 1.0)
+		{
+			if(!(*consumed))
+			{
+				advanceFilter(next);
+				*distance -= 1.0;
+				*consumed = true;
+			}
+			else
+			{
+				return false;
+			}
+		}
+
+		doInterpolate((int)floor(*distance * (Real)m_phaseSteps), result);
+
+		return true;
+	}
+
 private:
 	float* m_taps;
 	float* m_alignedTaps;