1 files changed, 132 insertions, 0 deletions
diff --git a/tests/helpers/c/prng.c b/tests/helpers/c/prng.c
new file mode 100644
index 0000000000..bdcfb07af1
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+++ b/tests/helpers/c/prng.c
@@ -0,0 +1,132 @@
+/*
+ * 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")
+ *
+ * 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 <assert.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "prng.h"
+
+struct prng
+{
+  unsigned long long state1;
+  unsigned long long state2;
+};
+
+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 *rv = calloc(sizeof(*rv), 1);
+  assert(rv);
+
+  rv->state1 = rv->state2 = seed;
+
+  return rv;
+}
+
+unsigned 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;
+}
+
+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;
+}
+
+void
+prng_free(struct prng *prng)
+{
+  free(prng);
+}