core: add portable rand() macros

- add kam_rand(), kam_srand(), and KAM_RAND_MAX macros
- provides consistency on platforms that define RAND_MAX as 32767

rand/kam_rand.h

@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2016 Spencer Thomason
+ *
+ * This file is part of Kamailio, a free SIP server.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef __KAM_RAND_H__
+#define __KAM_RAND_H__
+
+#include <limits.h>
+#include <stdlib.h>
+
+#if RAND_MAX < INT_MAX
+#define KAM_RAND_MAX ((int) (0x7FFFFFFF)) /* (1<<31) - 1 */
+#define kam_rand(x) ((int)random(x))
+#define kam_srand(x) srandom(x)
+#else
+#define KAM_RAND_MAX RAND_MAX
+#define kam_rand(x) rand(x)
+#define kam_srand(x) srand(x)
+#endif
+
+#endif