1 files changed, 91 insertions, 0 deletions
diff --git a/externals/grill/idelay/delay.h b/externals/grill/idelay/delay.h
new file mode 100644
index 00000000..eaf1117a
--- /dev/null
+++ b/externals/grill/idelay/delay.h
@@ -0,0 +1,91 @@
+/* 
+
+idelay~ - interpolating delay using flext layer
+
+Copyright (c) 2002 Thomas Grill (xovo@gmx.net)
+For information on usage and redistribution, and for a DISCLAIMER OF ALL
+WARRANTIES, see the file, "license.txt," in this distribution.  
+
+*/
+
+#ifndef _IDELAY_DELAY_H
+#define _IDELAY_DELAY_H
+
+#include <math.h>
+#include <string.h>
+
+#define F float
+#define S t_sample
+#define I int
+#define V void
+
+template <class T>
+class DelayLine
+{ 
+public:
+	DelayLine(): buf(NULL),len(0),wpos(0) {}
+	DelayLine(I smps): buf(NULL),len(0),wpos(0) { SetLen(smps); }
+	~DelayLine() { if(buf) delete[] buf; }
+
+	V SetLen(I smps); 
+
+	V Put(T s);
+	T Get(F delsmps);
+
+	T *buf; I dim;
+	I wpos,len;
+};
+
+template <class T>
+V DelayLine<T>::SetLen(I smps)
+{
+	if(len != smps) {
+		if(buf) delete[] buf;
+		len = smps;
+		buf = new T[dim = (len+4)]; // some more samples for interpolation
+		memset(buf,0,dim*sizeof(T)); 
+		wpos = 4; 
+	}
+}
+
+template <class T>
+V DelayLine<T>::Put(T s)
+{
+	if(!len) return;
+	buf[wpos] = s;
+	if(wpos >= len) buf[wpos-len] = s; // initialize interpolation security zone
+	if(++wpos == dim) wpos -= len;
+}
+
+template <class T>
+T DelayLine<T>::Get(F delsmps)
+{
+	if(!len) return 0;
+	if(delsmps < 0) 
+		return buf[wpos-1];
+	else {
+    	if(delsmps > len-1) delsmps = (F)len-1;
+    	I idelsmps = (I)delsmps;
+
+		if(idelsmps == 0) {
+			const T *bp = buf+wpos;
+			const F r = 1.f-delsmps;
+			return (F)(r*(r-1)*bp[-3]/2.+(1-r*r)*bp[-2]+r*(r+1)*bp[-1]/2.);
+		}
+		else {
+			const T *bp = buf+wpos-idelsmps;
+			if(bp < (const T *)buf+4) bp += len;
+	    	const F r = 1.f-(delsmps - (F)idelsmps);
+			return (F)(
+				((2-r)*(r-1)*r*bp[-3])/6. + 
+				((r-2)*(r*r-1)*bp[-2])/2. + 
+				((2-r)*r*(r+1)*bp[-1])/2. + 
+				((r*r-1)*r*bp[0])/6.
+			);
+		}
+	}
+}
+
+
+#endif
+