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authorMattias Andrée <maandree@kth.se>2017-11-12 14:44:35 +0100
committerMattias Andrée <maandree@kth.se>2017-11-12 14:54:29 +0100
commit67a395794b678d7da053c3daf61eb12d3f9437f2 (patch)
tree26be121e2738954a648d4032e8798723034960d7 /difftimespec.c
parentMore functions and add makefile (diff)
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Split into multiple units
Signed-off-by: Mattias Andrée <maandree@kth.se>
Diffstat (limited to 'difftimespec.c')
-rw-r--r--difftimespec.c50
1 files changed, 50 insertions, 0 deletions
diff --git a/difftimespec.c b/difftimespec.c
new file mode 100644
index 0000000..4ea74a8
--- /dev/null
+++ b/difftimespec.c
@@ -0,0 +1,50 @@
+/* See LICENSE file for copyright and license details. */
+#include "libsimple.h"
+
+
+int
+libsimple_difftimespec(struct timespec *diff, const struct timespec *minuend, const struct timespec *subtrahend)
+{
+ long int ns = minuend->tv_nsec - subtrahend->tv_nsec;
+ time_t s;
+ int ret = 0;
+
+ s = minuend->tv_sec - subtrahend->tv_sec;
+ if ((minuend->tv_sec <= 0) != (subtrahend->tv_sec <= 0)) {
+ if (minuend->tv_sec < 0 && minuend->tv_sec < TIME_MIN + subtrahend->tv_sec) {
+ s = TIME_MIN;
+ ns = 0;
+ errno = ERANGE;
+ ret = -1;
+ } else if (minuend->tv_sec >= 0 && minuend->tv_sec > TIME_MAX + subtrahend->tv_sec) {
+ s = TIME_MAX;
+ ns = 999999999L;
+ 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;
+ }
+ }
+
+ diff->tv_sec = s;
+ diff->tv_nsec = ns;
+ return ret;
+}