Add a shift function

2 files changed, 17 insertions, 0 deletions

diff --git a/fft.c b/fft.c
index f903dd4..1897d7e 100644
--- a/fft.c
+++ b/fft.c
@@ -76,3 +76,16 @@ ifft (complex_t *buffer, int n)
 
     do_fft (buffer, n, p, TRUE);
 }
+
+void
+shift (complex_t *buffer, int n)
+{
+    int i;
+
+    for (i = 0; i < n / 2; ++i)
+    {
+	complex_t tmp = buffer[i];
+	buffer[i] = buffer[i + n/2];
+	buffer[i + n/2] = tmp;
+    }
+}
diff --git a/fft.h b/fft.h
index 8a4e20e..35a756d 100644
--- a/fft.h
+++ b/fft.h
@@ -67,3 +67,7 @@ fft (complex_t *buffer, int n);
 
 void
 ifft (complex_t *buffer, int n);
+
+/* Shifts the zero component to the center of the array */
+void
+shift (complex_t *buffer, int n);