1 files changed, 75 insertions, 0 deletions
diff --git a/src/prime.c b/src/prime.c
new file mode 100644
index 0000000..2277019
--- /dev/null
+++ b/src/prime.c
@@ -0,0 +1,75 @@
+/******************************************************
+ *
+ * zexy - implementation file
+ *
+ * copyleft (c) IOhannes m zmölnig
+ *
+ *   1999:forum::für::umläute:2004
+ *
+ *   institute of electronic music and acoustics (iem)
+ *
+ ******************************************************
+ *
+ * license: GNU General Public License v.2
+ *
+ ******************************************************/
+
+/* get the n-th prime number */
+
+#include "zexy.h"
+#include <math.h>
+
+
+static t_class *prime_class;
+
+typedef struct _prime {
+  t_object  x_obj;
+} t_prime;
+
+
+void prime_float(t_prime *x, t_float f)
+{
+
+  unsigned int i=f;
+  unsigned int max_divisor;
+  unsigned int divisor=1;
+
+  if (f<2){
+    outlet_float(x->x_obj.ob_outlet, 0.0);
+    return;
+  }
+
+  if (!(i%2)){
+    outlet_float(x->x_obj.ob_outlet, (t_float)(i==2));
+    return;
+  }
+
+  max_divisor = sqrt(f)+1;
+
+  while ((divisor+=2)<max_divisor)
+    if (!(i%divisor)) {
+      outlet_float(x->x_obj.ob_outlet, 0.0);
+      return;
+    }
+
+  outlet_float(x->x_obj.ob_outlet, 1.0);
+}
+
+void *prime_new(void)
+{
+  t_prime *x = (t_prime *)pd_new(prime_class);
+
+  outlet_new(&x->x_obj, &s_float);
+
+  return (void *)x;
+}
+
+void prime_setup(void) {
+  prime_class = class_new(gensym("prime"),
+			  (t_newmethod)prime_new,
+			  0, sizeof(t_prime),
+			  CLASS_DEFAULT, 0);
+
+  class_addfloat(prime_class, prime_float);
+  zexy_register("prime");
+}