1 files changed, 141 insertions, 0 deletions
diff --git a/src/lib/time_utils.c b/src/lib/time_utils.c
new file mode 100644
index 00000000..2521f217
--- /dev/null
+++ b/src/lib/time_utils.c
@@ -0,0 +1,141 @@
+/*
+ * Ouroboros - Copyright (C) 2016
+ *
+ * Time utilities
+ *
+ *    Dimitri Staessens <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <ouroboros/time_utils.h>
+#include <stddef.h>
+
+/* functions for timespecs */
+
+/* add intv to t and store it in res*/
+int ts_add(const struct timespec * t,
+           const struct timespec * intv,
+           struct timespec *       res)
+{
+        long nanos = 0;
+
+        if (t == NULL || intv == NULL || res == NULL)
+                return -1;
+
+        nanos = t->tv_nsec + intv->tv_nsec;
+
+        res->tv_sec = t->tv_sec + intv->tv_sec;
+        while (nanos > BILLION) {
+                nanos -= BILLION;
+                ++(res->tv_sec);
+        }
+        res->tv_nsec = nanos;
+
+        return 0;
+}
+
+/* subtract intv from t and stores it in res */
+int ts_diff(const struct timespec * t,
+            const struct timespec * intv,
+            struct timespec *       res)
+{
+        long nanos = 0;
+
+        if (t == NULL || intv == NULL || res == NULL)
+                return -1;
+
+        nanos = t->tv_nsec - intv->tv_nsec;
+
+        res->tv_sec = t->tv_sec - intv->tv_sec;
+        while (nanos < 0) {
+                nanos += BILLION;
+                --(res->tv_sec);
+        }
+        res->tv_nsec = nanos;
+
+        return 0;
+}
+
+/* functions for timevals */
+
+/* add intv to t and store it in res*/
+int tv_add(const struct timeval * t,
+           const struct timeval * intv,
+           struct timeval *       res)
+{
+        long micros = 0;
+
+        if (t == NULL || intv == NULL || res == NULL)
+                return -1;
+
+        micros = t->tv_usec + intv->tv_usec;
+
+        res->tv_sec = t->tv_sec + intv->tv_sec;
+        while (micros > MILLION) {
+                micros -= MILLION;
+                --(res->tv_sec);
+        }
+        res->tv_usec = micros;
+
+        return 0;
+}
+
+/* subtract intv from t and stores it in res */
+int tv_diff(const struct timeval * t,
+            const struct timeval * intv,
+            struct timeval       * res)
+{
+        long micros = 0;
+
+        if (t == NULL || intv == NULL || res == NULL)
+                return -1;
+
+        micros = t->tv_usec - intv->tv_usec;
+
+        res->tv_sec = t->tv_sec - intv->tv_sec;
+        while (micros < 0) {
+                micros += MILLION;
+                --(res->tv_sec);
+        }
+        res->tv_usec = micros;
+
+        return 0;
+}
+
+int tv_to_ts(const struct timeval * src,
+             struct timespec *      dst)
+{
+        if (src == NULL || dst == NULL)
+                return -1;
+
+        dst->tv_sec  = src->tv_sec;
+        dst->tv_nsec = src->tv_usec * 1000L;
+
+        return 0;
+}
+
+/* copying a timespec into a timeval (loss of resolution) */
+int ts_to_tv(const struct timespec * src,
+             struct timeval *        dst)
+{
+        if (src == NULL || dst == NULL)
+                return -1;
+
+        dst->tv_sec  = src->tv_sec;
+        dst->tv_usec = src->tv_nsec / 1000L;
+
+        return 0;
+}