nspawn: make -U a tiny bit smarter

[elogind.git] / src / basic / time-util.h

diff --git a/src/basic/time-util.h b/src/basic/time-util.h
index 61f263baeaaeb666c1002e702766df7517335177..3c3fcca57f39edf253402cde58f3c5476aab0e6f 100644 (file)
--- a/src/basic/time-util.h
+++ b/src/basic/time-util.h
@@ -1,5 +1,3 @@
-/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
-
 #pragma once
 
 /***
@@ -96,8 +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);
@@ -143,3 +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;
+}