+// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Very simple prng to allow for randomized tests with reproducable
* results.
*
* Copyright (C) 2012 by Open Source Routing.
* Copyright (C) 2012 by Internet Systems Consortium, Inc. ("ISC")
+ * Copyright (C) 2017 Christian Franke
*
* This file is part of Quagga
- *
- * Quagga 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, or (at your option) any
- * later version.
- *
- * Quagga 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 Quagga; see the file COPYING. If not, write to the Free
- * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
- * 02111-1307, USA.
*/
#include <zebra.h>
#include "prng.h"
-struct prng
-{
- unsigned long long state1;
- unsigned long long state2;
+struct prng {
+ uint64_t state;
};
-static char
-prng_bit(struct prng *prng)
-{
- prng->state1 *= 2416;
- prng->state1 += 374441;
- prng->state1 %= 1771875;
-
- if (prng->state1 % 2)
- {
- prng->state2 *= 84589;
- prng->state2 += 45989;
- prng->state2 %= 217728;
- }
-
- return prng->state2 % 2;
-}
-
-struct prng*
-prng_new(unsigned long long seed)
+struct prng *prng_new(unsigned long long seed)
{
- struct prng *rv = calloc(sizeof(*rv), 1);
- assert(rv);
+ struct prng *rv = calloc(sizeof(*rv), 1);
+ assert(rv);
- rv->state1 = rv->state2 = seed;
+ rv->state = seed;
- return rv;
+ return rv;
}
-unsigned int
-prng_rand(struct prng *prng)
+/*
+ * This implementation has originally been provided to musl libc by
+ * Szabolcs Nagy <nsz at port70 dot net> in 2013 under the terms of
+ * the MIT license.
+ * It is a simple LCG which D.E. Knuth attributes to C.E. Haynes in
+ * TAOCP Vol2 3.3.4
+ */
+int prng_rand(struct prng *prng)
{
- unsigned int i, rv = 0;
-
- for (i = 0; i < 32; i++)
- {
- rv |= prng_bit(prng);
- rv <<= 1;
- }
- return rv;
+ prng->state = 6364136223846793005ULL * prng->state + 1;
+ return prng->state >> 33;
}
-const char *
-prng_fuzz(struct prng *prng,
- const char *string,
- const char *charset,
- unsigned int operations)
+const char *prng_fuzz(struct prng *prng, const char *string,
+ const char *charset, unsigned int operations)
{
- static char buf[256];
- unsigned int charset_len;
- unsigned int i;
- unsigned int offset;
- unsigned int op;
- unsigned int character;
-
- assert(strlen(string) < sizeof(buf));
-
- strncpy(buf, string, sizeof(buf));
- charset_len = strlen(charset);
-
- for (i = 0; i < operations; i++)
- {
- offset = prng_rand(prng) % strlen(buf);
- op = prng_rand(prng) % 3;
-
- switch (op)
- {
- case 0:
- /* replace */
- character = prng_rand(prng) % charset_len;
- buf[offset] = charset[character];
- break;
- case 1:
- /* remove */
- memmove(buf + offset, buf + offset + 1, strlen(buf) - offset);
- break;
- case 2:
- /* insert */
- assert(strlen(buf) + 1 < sizeof(buf));
-
- memmove(buf + offset + 1, buf + offset, strlen(buf) + 1 - offset);
- character = prng_rand(prng) % charset_len;
- buf[offset] = charset[character];
- break;
- }
- }
- return buf;
+ static char buf[256];
+ unsigned int charset_len;
+ unsigned int i;
+ unsigned int offset;
+ unsigned int op;
+ unsigned int character;
+
+ assert(strlen(string) < sizeof(buf));
+
+ strncpy(buf, string, sizeof(buf));
+ charset_len = strlen(charset);
+
+ for (i = 0; i < operations; i++) {
+ offset = prng_rand(prng) % strlen(buf);
+ op = prng_rand(prng) % 3;
+
+ switch (op) {
+ case 0:
+ /* replace */
+ character = prng_rand(prng) % charset_len;
+ buf[offset] = charset[character];
+ break;
+ case 1:
+ /* remove */
+ memmove(buf + offset, buf + offset + 1,
+ strlen(buf) - offset);
+ break;
+ case 2:
+ /* insert */
+ assert(strlen(buf) + 1 < sizeof(buf));
+
+ memmove(buf + offset + 1, buf + offset,
+ strlen(buf) + 1 - offset);
+ character = prng_rand(prng) % charset_len;
+ buf[offset] = charset[character];
+ break;
+ }
+ }
+ return buf;
}
-void
-prng_free(struct prng *prng)
+void prng_free(struct prng *prng)
{
- free(prng);
+ free(prng);
}