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[v4,5/8] tst_timer: Add tst_timespec_sub_us()

Message ID 20190129173659.27901-5-rafael.tinoco@linaro.org
State New
Headers show
Series [v4,1/8] lib: add tst_clock_settime() to tst_clocks.h | expand

Commit Message

Rafael David Tinoco Jan. 29, 2019, 5:36 p.m. UTC 
This commit adds a tst_timespec_sub_us() function that subtracts
microseconds from a given timespec struct.

Signed-off-by: Rafael David Tinoco <rafael.tinoco@linaro.org>
---
 include/tst_timer.h | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
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Patch

diff --git a/include/tst_timer.h b/include/tst_timer.h
index b57adf7aa..043b71460 100644
--- a/include/tst_timer.h
+++ b/include/tst_timer.h
@@ -170,6 +170,23 @@  static inline struct timespec tst_timespec_add(struct timespec t1,
 	return res;
 }
 
+/*
+ * Subtracts us microseconds from t.
+ */
+static inline struct timespec tst_timespec_sub_us(struct timespec t,
+                                                  long long us)
+{
+	t.tv_sec -= us / 1000000;
+	t.tv_nsec -= (us % 1000000) * 1000;
+
+	if (t.tv_nsec < 0) {
+		t.tv_sec--;
+		t.tv_nsec += 1000000000;
+	}
+
+	return t;
+}
+
 /*
  * Returns difference between two timespec structures.
  */