time_utils.h: difftime_timespec()

1 files changed, 40 insertions, 0 deletions

diff --git a/include/time_utils.h b/include/time_utils.h
new file mode 100644
index 0000000..f80e116
--- /dev/null
+++ b/include/time_utils.h
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: Apache-2.0 */
+
+/* Copyright 2025 Thorsten Töpper
+ * vim:ts=4:sw=4:expandtab
+ */
+#ifndef TIME_UTILS_H
+#define TIME_UTILS_H
+
+#include <time.h>
+
+#define TU_MEASURE_TIME(clck, ts1, ts2, code) \
+    clock_gettime(clck, ts1); \
+    code \
+    clock_gettime(clck, ts2);
+
+int difftime_timespec(struct timespec ts1, struct timespec ts2, struct timespec *result);
+
+
+inline int difftime_timespec(struct timespec ts1, struct timespec ts2, struct timespec *result) {
+    if (result == NULL)
+        return -1;
+    result->tv_sec = 0;
+    result->tv_nsec = 0;
+
+    if (ts1.tv_sec > ts2.tv_sec ||
+        ( (ts1.tv_sec == ts2.tv_sec) && ts1.tv_nsec > ts2.tv_nsec))
+        return -2;
+
+    result->tv_sec = ts2.tv_sec - ts1.tv_sec;
+
+    if (ts1.tv_nsec > ts2.tv_nsec) {
+        result->tv_nsec = (ts2.tv_nsec+1000000000) - ts1.tv_nsec;
+    } else {
+        result->tv_nsec = ts2.tv_nsec - ts1.tv_nsec;
+    }
+    return 0;
+}
+
+#endif
+