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authorMatt Johnston <matt@ucc.asn.au>2006-03-21 16:20:59 +0000
committerMatt Johnston <matt@ucc.asn.au>2006-03-21 16:20:59 +0000
commitf7caf6f5c640cb1756c01184898f176438a3a0c2 (patch)
tree4d32de11b18d5f6296207961b5f25d0949af80c0 /libtommath/bn_mp_lcm.c
parente444f0cfe67c71d3f38854f27cefae9aea6c4cd9 (diff)
parent3f49fc5f2ca0ec4adb5cac081f502cbb86702efa (diff)
propagate from branch 'au.asn.ucc.matt.dropbear' (head 0501e6f661b5415eb76f3b312d183c3adfbfb712)
to branch 'au.asn.ucc.matt.dropbear.cli-agent' (head 01038174ec27245b51bd43a66c01ad930880f67b) --HG-- branch : agent-client extra : convert_revision : 12b2f59db65e7339d340e95ac67d6d9ddb193c2b
Diffstat (limited to 'libtommath/bn_mp_lcm.c')
-rw-r--r--libtommath/bn_mp_lcm.c56
1 files changed, 56 insertions, 0 deletions
diff --git a/libtommath/bn_mp_lcm.c b/libtommath/bn_mp_lcm.c
new file mode 100644
index 0000000..8e3a759
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+++ b/libtommath/bn_mp_lcm.c
@@ -0,0 +1,56 @@
+#include <tommath.h>
+#ifdef BN_MP_LCM_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, tomstdenis@iahu.ca, http://math.libtomcrypt.org
+ */
+
+/* computes least common multiple as |a*b|/(a, b) */
+int mp_lcm (mp_int * a, mp_int * b, mp_int * c)
+{
+ int res;
+ mp_int t1, t2;
+
+
+ if ((res = mp_init_multi (&t1, &t2, NULL)) != MP_OKAY) {
+ return res;
+ }
+
+ /* t1 = get the GCD of the two inputs */
+ if ((res = mp_gcd (a, b, &t1)) != MP_OKAY) {
+ goto LBL_T;
+ }
+
+ /* divide the smallest by the GCD */
+ if (mp_cmp_mag(a, b) == MP_LT) {
+ /* store quotient in t2 such that t2 * b is the LCM */
+ if ((res = mp_div(a, &t1, &t2, NULL)) != MP_OKAY) {
+ goto LBL_T;
+ }
+ res = mp_mul(b, &t2, c);
+ } else {
+ /* store quotient in t2 such that t2 * a is the LCM */
+ if ((res = mp_div(b, &t1, &t2, NULL)) != MP_OKAY) {
+ goto LBL_T;
+ }
+ res = mp_mul(a, &t2, c);
+ }
+
+ /* fix the sign to positive */
+ c->sign = MP_ZPOS;
+
+LBL_T:
+ mp_clear_multi (&t1, &t2, NULL);
+ return res;
+}
+#endif