diff libtommath/bn_mp_prime_is_divisible.c @ 297:79bf1023cf11 agent-client

propagate from branch 'au.asn.ucc.matt.dropbear' (head 0501e6f661b5415eb76f3b312d183c3adfbfb712) to branch 'au.asn.ucc.matt.dropbear.cli-agent' (head 01038174ec27245b51bd43a66c01ad930880f67b)
author Matt Johnston <matt@ucc.asn.au>
date Tue, 21 Mar 2006 16:20:59 +0000
parents eed26cff980b
children 5ff8218bcee9
line wrap: on
line diff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtommath/bn_mp_prime_is_divisible.c	Tue Mar 21 16:20:59 2006 +0000
@@ -0,0 +1,46 @@
+#include <tommath.h>
+#ifdef BN_MP_PRIME_IS_DIVISIBLE_C
+/* LibTomMath, multiple-precision integer library -- Tom St Denis
+ *
+ * LibTomMath is a library that provides multiple-precision
+ * integer arithmetic as well as number theoretic functionality.
+ *
+ * The library was designed directly after the MPI library by
+ * Michael Fromberger but has been written from scratch with
+ * additional optimizations in place.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ *
+ * Tom St Denis, [email protected], http://math.libtomcrypt.org
+ */
+
+/* determines if an integers is divisible by one 
+ * of the first PRIME_SIZE primes or not
+ *
+ * sets result to 0 if not, 1 if yes
+ */
+int mp_prime_is_divisible (mp_int * a, int *result)
+{
+  int     err, ix;
+  mp_digit res;
+
+  /* default to not */
+  *result = MP_NO;
+
+  for (ix = 0; ix < PRIME_SIZE; ix++) {
+    /* what is a mod LBL_prime_tab[ix] */
+    if ((err = mp_mod_d (a, ltm_prime_tab[ix], &res)) != MP_OKAY) {
+      return err;
+    }
+
+    /* is the residue zero? */
+    if (res == 0) {
+      *result = MP_YES;
+      return MP_OKAY;
+    }
+  }
+
+  return MP_OKAY;
+}
+#endif