time: Add TIMEVAL_EARLIER and TIMEVAL_DIFF_SEC macros.

Make it easy to compare 'struct timeval's and get their difference.

src/util-time.h

@@ -33,6 +33,17 @@ void TimeGet(struct timeval *);
 /** \brief intialize a 'struct timespec' from a 'struct timeval'. */
 #define FROM_TIMEVAL(timev) { .tv_sec = (timev).tv_sec, .tv_nsec = (timev).tv_usec * 1000 }
 
+/** \brief compare two 'struct timeval' and return the difference in seconds */
+#define TIMEVAL_DIFF_SEC(tv_new, tv_old) \
+    (uint64_t)((((uint64_t)(tv_new).tv_sec * 1000000 + (tv_new).tv_usec) - \
+                ((uint64_t)(tv_old).tv_sec * 1000000 + (tv_old).tv_usec)) / \
+               1000000)
+
+/** \brief compare two 'struct timeval' and return if the first is earlier than the second */
+#define TIMEVAL_EARLIER(tv_first, tv_second) \
+    (((tv_first).tv_sec < (tv_second).tv_sec) || \
+     ((tv_first).tv_sec == (tv_second).tv_sec && (tv_first).tv_usec < (tv_second).tv_usec))
+
 #ifdef UNITTESTS
 void TimeSet(struct timeval *);
 void TimeSetToCurrentTime(void);