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+/* 
+ * Copyright (c) 2008 MUSIC TECHNOLOGY GROUP (MTG)
+ *                         UNIVERSITAT POMPEU FABRA 
+ * 
+ * 
+ * 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
+ * 
+ */
+/*! \file tables.c
+ * \brief sin and sinc tables.
+ * 
+ * contains functions for creating and indexing the tables
+ */
+#include "sms.h"
+
+/*! \brief value to scale the sine-table-lookup phase */
+static sfloat fSineScale;
+/*! \brief inverse of fSineScale - turns a division into multiplication */
+static sfloat fSineIncr;
+/*! \brief value to scale the sinc-table-lookup phase */
+static sfloat fSincScale;
+/*! \brief global pointer to the sine table */
+static sfloat *sms_tab_sine;
+/*! \brief global pointer to the sinc table */
+static sfloat *sms_tab_sinc;
+
+/*! \brief prepares the sine table
+ * \param  nTableSize    size of table
+ * \return error code \see SMS_MALLOC in SMS_ERRORS
+ */
+int sms_prepSine (int nTableSize)
+{
+        register int i;
+        sfloat fTheta;
+  
+        if((sms_tab_sine = (sfloat *)malloc(nTableSize*sizeof(float))) == 0)
+                return (SMS_MALLOC);
+        fSineScale =  (sfloat)(TWO_PI) / (sfloat)(nTableSize - 1);
+        fSineIncr = 1.0 / fSineScale;
+        fTheta = 0.0;
+        for(i = 0; i < nTableSize; i++) 
+        {
+                fTheta = fSineScale * (sfloat)i;
+                sms_tab_sine[i] = sin(fTheta);
+        }
+        return (SMS_OK);
+}
+/*! \brief clear sine table */
+void sms_clearSine()
+{
+        if(sms_tab_sine)
+                free(sms_tab_sine);
+        sms_tab_sine = 0;
+}
+
+/*! \brief table-lookup sine method
+ * \param fTheta    angle in radians
+ * \return approximately sin(fTheta)
+ */
+sfloat sms_sine (sfloat fTheta)
+{
+        int i;
+        fTheta = fTheta - floor(fTheta * INV_TWO_PI) * TWO_PI;
+  
+        if(fTheta < 0)
+        {
+                i =  .5 - (fTheta * fSineIncr);
+                return(-(sms_tab_sine[i]));
+        }
+        else
+        {
+                i = fTheta * fSineIncr + .5;
+                return(sms_tab_sine[i]);
+        }
+}
+
+/*! \brief Sinc method to generate the lookup table
+ */
+static sfloat Sinc (sfloat x, sfloat N)	
+{
+	return (sinf ((N/2) * x) / sinf (x/2));
+}
+
+/*! \brief prepare the Sinc table
+ *
+ * used for the main lobe of a frequency domain 
+ * BlackmanHarris92 window
+ *
+ * \param  nTableSize    size of table
+ * \return error code \see SMS_MALLOC in SMS_ERRORS
+ */
+int sms_prepSinc (int nTableSize)
+{
+        int i, m;
+	sfloat N = 512.0;
+	sfloat fA[4] = {.35875, .48829, .14128, .01168};
+        sfloat fMax = 0;
+        sfloat fTheta = -4.0 * TWO_PI / N;
+        sfloat fThetaIncr = (8.0 * TWO_PI / N) / (nTableSize);
+
+        if((sms_tab_sinc = (sfloat *) calloc (nTableSize, sizeof(float))) == 0)
+                return (SMS_MALLOC);
+        
+        for(i = 0; i < nTableSize; i++) 
+        {
+                for (m = 0; m < 4; m++)
+                        sms_tab_sinc[i] +=  -1 * (fA[m]/2) * 
+                                (Sinc (fTheta - m * TWO_PI/N, N) + 
+                                 Sinc (fTheta + m * TWO_PI/N, N));
+                fTheta += fThetaIncr;
+        }
+        fMax = sms_tab_sinc[(int) nTableSize / 2];
+        for (i = 0; i < nTableSize; i++) 
+                sms_tab_sinc[i] = sms_tab_sinc[i] / fMax;
+        
+        fSincScale = (sfloat) nTableSize / 8.0;
+        
+        return (SMS_OK);
+}
+
+/*! \brief clear sine table */
+void sms_clearSinc()
+{
+        if(sms_tab_sinc)
+                free(sms_tab_sinc);
+        sms_tab_sinc = 0;
+}
+
+/*! \brief global sinc table-lookup method
+ * 
+ * fTheta has to be from 0 to 8
+ *
+ * \param fTheta    angle in radians
+ * \return approximately sinc(fTheta)
+ */
+sfloat sms_sinc (sfloat fTheta)
+{
+	int index = (int) (.5 + fSincScale * fTheta);
+
+	return (sms_tab_sinc[index]);
+}