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-rw-r--r--sumtimespec.c50
1 files changed, 50 insertions, 0 deletions
diff --git a/sumtimespec.c b/sumtimespec.c
new file mode 100644
index 0000000..11c5903
--- /dev/null
+++ b/sumtimespec.c
@@ -0,0 +1,50 @@
+/* See LICENSE file for copyright and license details. */
+#include "libsimple.h"
+
+
+int
+libsimple_sumtimespec(struct timespec *sum, const struct timespec *augend, const struct timespec *addend)
+{
+ long int ns = augend->tv_nsec + addend->tv_nsec;
+ time_t s;
+ int ret = 0;
+
+ s = augend->tv_sec + addend->tv_sec;
+ if ((augend->tv_sec < 0) == (addend->tv_sec < 0)) {
+ if (augend->tv_sec >= 0 && augend->tv_sec > TIME_MAX - addend->tv_sec) {
+ s = TIME_MAX;
+ ns = 999999999L;
+ errno = ERANGE;
+ ret = -1;
+ } else if (augend->tv_sec < 0 && augend->tv_sec + addend->tv_sec < TIME_MIN) {
+ s = TIME_MIN;
+ ns = 0;
+ errno = ERANGE;
+ ret = -1;
+ }
+ }
+
+ if (ns < 0) {
+ if (s == TIME_MIN) {
+ ns = 0L;
+ errno = ERANGE;
+ ret = -1;
+ } else {
+ s -= 1;
+ ns += 1000000000L;
+ }
+ } else if (ns >= 1000000000L) {
+ if (s == TIME_MAX) {
+ ns = 999999999L;
+ errno = ERANGE;
+ ret = -1;
+ } else {
+ s += 1;
+ ns -= 1000000000L;
+ }
+ }
+
+ sum->tv_sec = s;
+ sum->tv_nsec = ns;
+ return ret;
+}