add a bunch of files

filter.c

@@ -0,0 +1,57 @@
+#include "filter.h"
+#include <math.h>
+#include <string.h>
+
+
+void FilterFoldedBinsIIRTWOPASS( float * folded, int bins, float iir )
+{
+	int i;
+	float inv = 1.0 - iir;
+	float v = 0.0;
+
+	//Go through the data once, forward.
+	for( i = 0; i < bins; i++ )
+	{
+		v = v * iir + folded[i] * inv;
+	}
+
+	//Start applying filter on second pass.
+	for( i = 0; i < bins; i++ )
+	{
+		folded[i] = v * iir + folded[i] * inv;
+	}
+
+	//Go backwards.
+	v = 0;
+	for( i = bins-1; i >= 0; i-- )
+	{
+		v = v * iir + folded[i] * inv;
+	}
+
+	//Start applying filter on second pass.
+	for( i = bins-1; i >= 0; i-- )
+	{
+		folded[i] = v * iir + folded[i] * inv;
+	}
+
+}
+
+
+void FilterFoldedBinsBlob( float * folded, int bins, float strength, int iter )
+{
+	float tmp[bins];
+	int i;
+	int j;
+	for( j = 0; j < iter; j++ )
+	{
+		memcpy( tmp, folded, sizeof( tmp ) );
+		for( i = 0; i < bins; i++ )
+		{
+			float left = tmp[(i-1+bins)%bins];
+			float right = tmp[(i-1+bins)%bins];
+			folded[i] = folded[i] * (1.-strength) + (left + right) * strength * 0.5;
+		}
+	}
+
+}
+