1 files changed, 94 insertions, 0 deletions
diff --git a/src/timeval_functions.c b/src/timeval_functions.c
index 84bfe7e..394b654 100644
--- a/src/timeval_functions.c
+++ b/src/timeval_functions.c
@@ -20,6 +20,9 @@
 
 #include <config.h>
 
+#include <stdlib.h>
+#include <assert.h>
+
 #include "timeval_functions.h"
 
 /*
@@ -38,3 +41,94 @@ timeval_create(long tv_sec, long tv_usec)
   tmp.tv_usec = tv_usec;
   return tmp;
 }
+
+/*
+ * Function name: timeval_compare
+ * Description: Compares two pointers to timeval structures.
+ * Arguments: first - the first timeval structure to compare
+ *            second - the second timeval structure to compare
+ * Returns: -1 - the second structure is bigger
+ *           0 - structures are equals
+ *           1 - the first structure is bigger
+ */
+
+int
+timeval_compare(struct timeval* first, struct timeval* second)
+{
+  if (first == NULL) {
+    if (second == NULL) {
+      return 0;
+    }
+    else {
+      return -1;
+    }
+  }
+  if (second == NULL) {
+    return 1;
+  }
+  if (first->tv_sec < second->tv_sec) {
+    return -1;
+  }
+  if (first->tv_sec > second->tv_sec) {
+    return 1;
+  }
+  if (first->tv_usec < second->tv_usec) {
+    return -1;
+  }
+  if (first->tv_usec > second->tv_usec) {
+    return 1;
+  }
+  return 0;
+}
+
+/*
+ * Function name: timeval_subtract
+ * Description: Substracts second timeval structure from the first, updating the latter one.
+ * Arguments: first - the first timeval structure to subtract operation
+ *            second - the second timeval structure to subtract operation
+ * Returns: 0 - success,
+ *          1 - failure.
+ */
+
+int
+timeval_subtract(struct timeval* first, struct timeval* second)
+{
+  assert(first != NULL);
+  assert(second != NULL);
+  if ((first == NULL) || (second == NULL)) {
+    return 1;
+  }
+  if (first->tv_usec < second->tv_usec) {
+    first->tv_sec -= 1;
+    first->tv_usec = 1000000 - second->tv_usec + first->tv_usec;
+  }
+  else {
+    first->tv_usec -= second->tv_usec;
+  }
+  first->tv_sec -= second->tv_sec;
+  return 0;
+}
+
+/*
+ * Function name: timeval_lq_zero
+ * Description: Checks if the timer is less or equiv zero.
+ * Arguments: timer - the timeval structure to check
+ * Returns: 1 - the timer is less or equiv zero,
+ *          0 - the timer is bigger than zero.
+ */
+
+int
+timeval_lq_zero(struct timeval* timer)
+{
+  assert(timer != NULL);
+  if (timer == NULL) {
+    return 0;
+  }
+  if (timer->tv_sec < 0) {
+    return 1;
+  }
+  if ((timer->tv_sec == 0) && (timer->tv_usec == 0)) {
+    return 1;
+  }
+  return 0;
+}