Diff: prng.h

Revision:

0:04990d454f45

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/prng.h	Thu Oct 10 21:38:07 2013 +0000
@@ -0,0 +1,89 @@
+/* prng.h -- Pseudo Random Numbers
+ *
+ * Copyright (C) 2010--2012 Olaf Bergmann <bergmann@tzi.org>
+ *
+ * This file is part of the library tinydtls. Please see
+ * README for terms of use. 
+ */
+
+/** 
+ * @file prng.h
+ * @brief Pseudo Random Numbers
+ */
+
+#ifndef _DTLS_PRNG_H_
+#define _DTLS_PRNG_H_
+
+#include "config.h"
+
+/** 
+ * @defgroup prng Pseudo Random Numbers
+ * @{
+ */
+
+#ifndef WITH_CONTIKI
+#include <stdlib.h>
+
+/**
+ * Fills \p buf with \p len random bytes. This is the default
+ * implementation for prng().  You might want to change prng() to use
+ * a better PRNG on your specific platform.
+ */
+static inline int
+dtls_prng_impl(unsigned char *buf, size_t len) {
+  while (len--)
+    *buf++ = rand() & 0xFF;
+  return 1;
+}
+#else /* WITH_CONTIKI */
+#include <string.h>
+
+#ifdef HAVE_PRNG
+extern int contiki_prng_impl(unsigned char *buf, size_t len);
+#else
+/**
+ * Fills \p buf with \p len random bytes. This is the default
+ * implementation for prng().  You might want to change prng() to use
+ * a better PRNG on your specific platform.
+ */
+static inline int
+contiki_prng_impl(unsigned char *buf, size_t len) {
+  unsigned short v = random_rand();
+  while (len > sizeof(v)) {
+    memcpy(buf, &v, sizeof(v));
+    len -= sizeof(v);
+    buf += sizeof(v);
+    v = random_rand();
+  }
+
+  memcpy(buf, &v, len);
+  return 1;
+}
+#endif /* HAVE_PRNG */
+
+#define prng(Buf,Length) contiki_prng_impl((Buf), (Length))
+#define prng_init(Value) random_init((unsigned short)(Value))
+#endif /* WITH_CONTIKI */
+
+#ifndef prng
+/** 
+ * Fills \p Buf with \p Length bytes of random data. 
+ * 
+ * @hideinitializer
+ */
+#define prng(Buf,Length) dtls_prng_impl((Buf), (Length))
+#endif
+
+#ifndef prng_init
+/** 
+ * Called to set the PRNG seed. You may want to re-define this to
+ * allow for a better PRNG.
+ *
+ * @hideinitializer
+ */
+#define prng_init(Value) srand((unsigned long)(Value))
+#endif
+
+/** @} */
+
+#endif /* _DTLS_PRNG_H_ */