1 files changed, 29 insertions, 0 deletions
diff --git a/util.c b/util.c
index 37bd9e8..5a55a05 100644
--- a/util.c
+++ b/util.c
@@ -198,3 +198,32 @@ bool hex2bin(unsigned char *p, const char *hexstr, size_t len)
 	return (len == 0 && *hexstr == 0) ? true : false;
 }
 
+/* Subtract the `struct timeval' values X and Y,
+   storing the result in RESULT.
+   Return 1 if the difference is negative, otherwise 0.  */
+
+int
+timeval_subtract (
+     struct timeval *result, struct timeval *x, struct timeval *y)
+{
+  /* Perform the carry for the later subtraction by updating Y. */
+  if (x->tv_usec < y->tv_usec) {
+    int nsec = (y->tv_usec - x->tv_usec) / 1000000 + 1;
+    y->tv_usec -= 1000000 * nsec;
+    y->tv_sec += nsec;
+  }
+  if (x->tv_usec - y->tv_usec > 1000000) {
+    int nsec = (x->tv_usec - y->tv_usec) / 1000000;
+    y->tv_usec += 1000000 * nsec;
+    y->tv_sec -= nsec;
+  }
+
+  /* Compute the time remaining to wait.
+     `tv_usec' is certainly positive. */
+  result->tv_sec = x->tv_sec - y->tv_sec;
+  result->tv_usec = x->tv_usec - y->tv_usec;
+
+  /* Return 1 if result is negative. */
+  return x->tv_sec < y->tv_sec;
+}
+