add fftshift functions,header and interface

1 files changed, 48 insertions, 0 deletions

diff --git a/src/signalProcessing/fftshift/crowfftshifta.c b/src/signalProcessing/fftshift/crowfftshifta.c
new file mode 100644
index 00000000..99b807ec
--- /dev/null
+++ b/src/signalProcessing/fftshift/crowfftshifta.c
@@ -0,0 +1,48 @@
+/*
+ *  Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
+ *  Copyright (C) 2008 - INRIA - Arnaud TORSET
+ *
+ *  This file must be used under the terms of the CeCILL.
+ *  This source file is licensed as described in the file COPYING, which
+ *  you should have received as part of this distribution.  The terms
+ *  are also available at
+ *  http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt
+ *
+ */
+
+
+#include "fftshift.h"
+
+static void Pair(floatComplex* in,int rows,int columns,floatComplex* out){
+	int i=0,j=0;
+
+	for (i=0;i<rows;i++)
+		for(j=0;j<columns;j++)
+			out[i+j*rows]=in[j*rows+((rows/2)+i)%rows];
+}
+
+
+static void Odd(floatComplex* in,int rows,int columns,floatComplex* out){
+	int i=0,j=0;
+
+	/*
+		same as Pair with some change in the indice
+	*/
+	for (i=0;i<rows;i++)
+		for(j=0;j<columns;j++)
+			out[i+j*rows]=in[j*rows+(((rows+1)/2)+i)%rows];
+}
+
+
+
+
+
+
+void crowfftshifta(floatComplex* in,int rows,int columns,floatComplex* out){	
+	switch(rows%2){
+		case 0 : Pair(in,rows,columns,out); break; 
+		case 1 : Odd(in,rows,columns,out); break; 
+		default : break;
+	}
+}
+