Diff: wolfcrypt/src/wolfmath.c

Revision:

6:fa3bd0ca5896

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/wolfcrypt/src/wolfmath.c	Tue May 02 08:44:26 2017 +0000
@@ -0,0 +1,108 @@
+/* wolfmath.c
+ *
+ * Copyright (C) 2006-2016 wolfSSL Inc.
+ *
+ * This file is part of wolfSSL.
+ *
+ * wolfSSL is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * wolfSSL is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
+ */
+
+
+/* common functions for either math library */
+
+#ifdef HAVE_CONFIG_H
+    #include <config.h>
+#endif
+
+/* in case user set USE_FAST_MATH there */
+#include <wolfssl/wolfcrypt/settings.h>
+
+#ifdef USE_FAST_MATH
+    #include <wolfssl/wolfcrypt/tfm.h>
+#else
+    #include <wolfssl/wolfcrypt/integer.h>
+#endif
+
+#include <wolfssl/wolfcrypt/error-crypt.h>
+#include <wolfssl/wolfcrypt/logging.h>
+
+#if defined(USE_FAST_MATH) || !defined(NO_BIG_INT)
+
+int get_digit_count(mp_int* a)
+{
+    if (a == NULL)
+        return 0;
+
+    return a->used;
+}
+
+mp_digit get_digit(mp_int* a, int n)
+{
+    if (a == NULL)
+        return 0;
+
+    return (n >= a->used || n < 0) ? 0 : a->dp[n];
+}
+
+int get_rand_digit(WC_RNG* rng, mp_digit* d)
+{
+    return wc_RNG_GenerateBlock(rng, (byte*)d, sizeof(mp_digit));
+}
+
+int mp_rand(mp_int* a, int digits, WC_RNG* rng)
+{
+    int ret;
+    mp_digit d;
+
+    if (rng == NULL)
+        return MISSING_RNG_E;
+
+    if (a == NULL)
+        return BAD_FUNC_ARG;
+
+    mp_zero(a);
+    if (digits <= 0) {
+        return MP_OKAY;
+    }
+
+    /* first place a random non-zero digit */
+    do {
+        ret = get_rand_digit(rng, &d);
+        if (ret != 0) {
+            return ret;
+        }
+    } while (d == 0);
+
+    if ((ret = mp_add_d(a, d, a)) != MP_OKAY) {
+        return ret;
+    }
+
+    while (--digits > 0) {
+        if ((ret = mp_lshd(a, 1)) != MP_OKAY) {
+            return ret;
+        }
+        if ((ret = get_rand_digit(rng, &d)) != 0) {
+            return ret;
+        }
+        if ((ret = mp_add_d(a, d, a)) != MP_OKAY) {
+            return ret;
+        }
+    }
+
+    return ret;
+}
+
+#endif
+