diff options
| -rw-r--r-- | src/basic/time-util.h | 14 | ||||
| -rw-r--r-- | src/test/test-time.c | 13 |
2 files changed, 21 insertions, 6 deletions
diff --git a/src/basic/time-util.h b/src/basic/time-util.h index 87440faeee..080c1110f5 100644 --- a/src/basic/time-util.h +++ b/src/basic/time-util.h @@ -143,11 +143,13 @@ static inline usec_t usec_add(usec_t a, usec_t b) { static inline usec_t usec_sub(usec_t timestamp, int64_t delta) { if (delta < 0) - timestamp = usec_add(timestamp, (usec_t) (-delta)); - else if (timestamp > (usec_t) delta) - timestamp -= delta; - else - timestamp = 0; + return usec_add(timestamp, (usec_t) (-delta)); - return timestamp; + if (timestamp == USEC_INFINITY) /* Make sure infinity doesn't degrade */ + return USEC_INFINITY; + + if (timestamp < (usec_t) delta) + return 0; + + return timestamp - delta; } diff --git a/src/test/test-time.c b/src/test/test-time.c index 254a8d0e52..fdbf9fa881 100644 --- a/src/test/test-time.c +++ b/src/test/test-time.c @@ -191,6 +191,18 @@ static void test_usec_add(void) { assert_se(usec_add(USEC_INFINITY, 2) == USEC_INFINITY); } +static void test_usec_sub(void) { + assert_se(usec_sub(0, 0) == 0); + assert_se(usec_sub(4, 1) == 3); + assert_se(usec_sub(4, 4) == 0); + assert_se(usec_sub(4, 5) == 0); + assert_se(usec_sub(USEC_INFINITY-3, -3) == USEC_INFINITY); + assert_se(usec_sub(USEC_INFINITY-3, -3) == USEC_INFINITY); + assert_se(usec_sub(USEC_INFINITY-3, -4) == USEC_INFINITY); + assert_se(usec_sub(USEC_INFINITY-3, -5) == USEC_INFINITY); + assert_se(usec_sub(USEC_INFINITY, 5) == USEC_INFINITY); +} + int main(int argc, char *argv[]) { uintmax_t x; @@ -203,6 +215,7 @@ int main(int argc, char *argv[]) { test_timezone_is_valid(); test_get_timezones(); test_usec_add(); + test_usec_sub(); /* Ensure time_t is signed */ assert_cc((time_t) -1 < (time_t) 1); |