1 files changed, 110 insertions, 0 deletions
diff --git a/arts/modules/synth/synth_rc_impl.cc b/arts/modules/synth/synth_rc_impl.cc
new file mode 100644
index 00000000..0c62c4c6
--- /dev/null
+++ b/arts/modules/synth/synth_rc_impl.cc
@@ -0,0 +1,110 @@
+/*
+
+    Copyright (C) 2000 Jeff Tranter
+                       tranter@pobox.com
+
+              (C) 1999 Stefan Westerfeld
+                       stefan@space.twc.de
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+
+    */
+
+#include <math.h>
+#include "artsmodulessynth.h"
+#include "stdsynthmodule.h"
+
+using namespace Arts;
+
+class Synth_RC_impl : virtual public Synth_RC_skel,
+								 virtual public StdSynthModule
+{
+protected:
+	float _b, _f;
+	float B, dB;
+	float F, dF, oF, oU, U, Fsoll, Bsoll;
+	float oldvalue;
+
+public:
+	float b() { return _b; }
+	void b(float newB) { _b = newB; }
+
+	float f() { return _f; }
+	void f(float newF) { _f = newF; }
+
+	void streamInit()
+	{
+		oldvalue = 0;
+		B = 0;
+		F = 0; oF = 0;
+		U = 0; oU = 0;
+	}
+	
+	void calculateBlock(unsigned long samples)
+	{
+		unsigned long i, hits;
+		const float zero_lower = -0.00000001;
+		const float zero_upper =  0.00000001;
+
+		if (zero_lower < invalue[0] && invalue[0] < zero_upper)
+		{
+			/* for comments see equalizer.cc/Synth_STD_EQUALIZER implementation */
+			
+			/*
+			 * This implementation differs from the implementation there,
+			 * because it is done as a kind of powersafing. If no input is
+			 * found, then no output is generated.
+			 */
+			if (zero_lower < oldvalue && oldvalue < zero_upper)
+			{
+				oldvalue = 0.0;
+				B = 0.0;
+				F = 0.0; oF = 0.0;
+				U = 0.0; oU = 0.0;
+				hits = 0;
+				for (i=0; i<samples; i++)
+				{
+					if (zero_lower < invalue[i] && invalue[i] < zero_upper)
+					{
+						// try to zero out the whole block
+						outvalue[i] = 0.0;
+						hits++;
+					}
+				}
+				if (hits == samples) return;
+			}
+		}
+
+		for (i=0; i<samples; i++)
+		{
+			B = B + (invalue[i] - oldvalue); /* input into RC */
+			oldvalue = invalue[i];
+
+			Bsoll = U - oU;
+			oU = U;
+			dB = (Bsoll - B) / _b;
+			B += dB;
+			U -= dB;
+			Fsoll = U;
+			dF = (Fsoll - F) / _f;
+			F += dF;                 /* Energie dF wird ins Feld uebertragen */
+			U -= dF;
+			outvalue[i] = (F - oF) * (_b + _f);
+			oF = F;
+		}
+	}
+};
+
+REGISTER_IMPLEMENTATION(Synth_RC_impl);