1 files changed, 26 insertions, 2 deletions
diff --git a/src/basic/time-util.h b/src/basic/time-util.h
index 7d2d5fa10..3c3fcca57 100644
--- a/src/basic/time-util.h
+++ b/src/basic/time-util.h
@@ -94,8 +94,6 @@ struct timespec *timespec_store(struct timespec *ts, usec_t u);
 usec_t timeval_load(const struct timeval *tv) _pure_;
 struct timeval *timeval_store(struct timeval *tv, usec_t u);
 
-nsec_t timespec_load_nsec(const struct timespec *ts) _pure_;
-
 char *format_timestamp(char *buf, size_t l, usec_t t);
 #if 0 /// UNNEEDED by elogind
 char *format_timestamp_utc(char *buf, size_t l, usec_t t);
@@ -141,3 +139,29 @@ struct tm *localtime_or_gmtime_r(const time_t *t, struct tm *tm, bool utc);
 #if 0 /// UNNEEDED by elogind
 unsigned long usec_to_jiffies(usec_t usec);
 #endif // 0
+
+static inline usec_t usec_add(usec_t a, usec_t b) {
+        usec_t c;
+
+        /* Adds two time values, and makes sure USEC_INFINITY as input results as USEC_INFINITY in output, and doesn't
+         * overflow. */
+
+        c = a + b;
+        if (c < a || c < b) /* overflow check */
+                return USEC_INFINITY;
+
+        return c;
+}
+
+static inline usec_t usec_sub(usec_t timestamp, int64_t delta) {
+        if (delta < 0)
+                return usec_add(timestamp, (usec_t) (-delta));
+
+        if (timestamp == USEC_INFINITY) /* Make sure infinity doesn't degrade */
+                return USEC_INFINITY;
+
+        if (timestamp < (usec_t) delta)
+                return 0;
+
+        return timestamp - delta;
+}