Version 0.99

DLineL.cpp

@@ -0,0 +1,90 @@
+/*******************************************/
+/*  Linearly Interpolating Delay Line      */
+/*  Object by Perry R. Cook 1995-96        */
+/*  This one uses a delay line of maximum  */
+/*  length specified on creation, and      */ 
+/*  linearly interpolates fractional       */
+/*  length.  It is designed to be more     */
+/*  efficient if the delay length is not   */
+/*  changed very often.                    */
+/*******************************************/
+
+#include "DLineL.h"
+
+DLineL :: DLineL(long max_length)
+{
+    length = max_length;
+    inputs = (MY_FLOAT *) malloc(length * MY_FLOAT_SIZE);
+    this->clear();
+    outPoint = 0;
+    inPoint = length >> 1;
+}
+
+DLineL :: ~DLineL()
+{
+    free(inputs);
+}
+
+void DLineL :: clear()
+{
+    long i;
+    for (i=0;i<length;i++) inputs[i] = 0.0;
+    lastOutput = 0;
+}
+
+void DLineL :: setDelay(MY_FLOAT lag)
+{
+    MY_FLOAT outputPointer;
+    outputPointer = inPoint - lag;       /* read chases write, add 1 for interp.   */
+    while (outputPointer<0)
+	outputPointer += length;         /* modulo maximum length                  */
+    outPoint = (long) outputPointer;     /* integer part                           */
+    alpha = outputPointer - outPoint;    /* fractional part                        */
+    omAlpha = 1.0 - alpha;               /* 1.0 - fractional part (more efficient) */
+}
+
+MY_FLOAT DLineL :: tick(MY_FLOAT sample)        /*   Take one, yield one           */
+{
+    inputs[inPoint++] = sample;                 /*  Input next sample              */
+    if (inPoint == length)                      /*  Check for end condition        */
+	inPoint -= length;
+    lastOutput = inputs[outPoint++] * omAlpha;  /*  first 1/2 of interpolation     */
+    if (outPoint<length)        {               /*  Check for end condition        */
+	lastOutput += inputs[outPoint] * alpha; /*  second 1/2 of interpolation    */
+    }                                          
+    else        {                               /*  if at end . . .                */
+	lastOutput += inputs[0] * alpha;        /*  second 1/2 of interpolation    */
+	outPoint -= length;                             
+    }
+    return lastOutput;
+}
+
+/************   Test Main Program   *****************/
+/*
+
+void main()
+{
+    DLineL delay(140);
+    FILE *fd;
+    MY_FLOAT temp;
+    short data;
+    long i;
+    
+    fd = fopen("test.raw","wb");
+    
+    delay.setDelay(128);
+    for (i=0;i<4096;i++) {
+	if (i%256 != 0) temp = 0.0; else temp = 1.0;
+	data = (temp + delay.tick(temp)) * 16000.0;
+	fwrite(&data,2,1,fd);
+    }
+    delay.setDelay(64.5);
+    for (i=0;i<4096;i++) {
+	if (i%256 != 0) temp = 0.0; else temp = 1.0;
+	data = (temp + delay.tick(temp)) * 16000.0;
+	fwrite(&data,2,1,fd);
+    }
+    
+    fclose(fd);
+}
+*/