1 files changed, 84 insertions, 0 deletions
diff --git a/security/nss/lib/freebl/mpi/utils/fact.c b/security/nss/lib/freebl/mpi/utils/fact.c
new file mode 100644
index 000000000..da8e61a32
--- /dev/null
+++ b/security/nss/lib/freebl/mpi/utils/fact.c
@@ -0,0 +1,84 @@
+/*
+ * fact.c
+ *
+ * Compute factorial of input integer
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "mpi.h"
+
+mp_err mp_fact(mp_int *a, mp_int *b);
+
+int
+main(int argc, char *argv[])
+{
+    mp_int a;
+    mp_err res;
+
+    if (argc < 2) {
+        fprintf(stderr, "Usage: %s <number>\n", argv[0]);
+        return 1;
+    }
+
+    mp_init(&a);
+    mp_read_radix(&a, argv[1], 10);
+
+    if ((res = mp_fact(&a, &a)) != MP_OKAY) {
+        fprintf(stderr, "%s: error: %s\n", argv[0],
+                mp_strerror(res));
+        mp_clear(&a);
+        return 1;
+    }
+
+    {
+        char *buf;
+        int len;
+
+        len = mp_radix_size(&a, 10);
+        buf = malloc(len);
+        mp_todecimal(&a, buf);
+
+        puts(buf);
+
+        free(buf);
+    }
+
+    mp_clear(&a);
+    return 0;
+}
+
+mp_err
+mp_fact(mp_int *a, mp_int *b)
+{
+    mp_int ix, s;
+    mp_err res = MP_OKAY;
+
+    if (mp_cmp_z(a) < 0)
+        return MP_UNDEF;
+
+    mp_init(&s);
+    mp_add_d(&s, 1, &s); /* s = 1  */
+    mp_init(&ix);
+    mp_add_d(&ix, 1, &ix); /* ix = 1 */
+
+    for (/*  */; mp_cmp(&ix, a) <= 0; mp_add_d(&ix, 1, &ix)) {
+        if ((res = mp_mul(&s, &ix, &s)) != MP_OKAY)
+            break;
+    }
+
+    mp_clear(&ix);
+
+    /* Copy out results if we got them */
+    if (res == MP_OKAY)
+        mp_copy(&s, b);
+
+    mp_clear(&s);
+
+    return res;
+}