Merge branch 'release/0.0.1'

[catta] / src / timeval.c

diff --git a/src/timeval.c b/src/timeval.c
new file mode 100644 (file)
index 0000000..5ed395f
--- /dev/null
+++ b/src/timeval.c
@@ -0,0 +1,123 @@
+/***
+  This file is part of catta.
+
+  catta is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as
+  published by the Free Software Foundation; either version 2.1 of the
+  License, or (at your option) any later version.
+
+  catta 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 Lesser General
+  Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with catta; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <pthread.h>
+#include <stdlib.h>
+#include <assert.h>
+
+#include <catta/timeval.h>
+
+int catta_timeval_compare(const struct timeval *a, const struct timeval *b) {
+    assert(a);
+    assert(b);
+
+    if (a->tv_sec < b->tv_sec)
+        return -1;
+
+    if (a->tv_sec > b->tv_sec)
+        return 1;
+
+    if (a->tv_usec < b->tv_usec)
+        return -1;
+
+    if (a->tv_usec > b->tv_usec)
+        return 1;
+
+    return 0;
+}
+
+CattaUsec catta_timeval_diff(const struct timeval *a, const struct timeval *b) {
+    assert(a);
+    assert(b);
+
+    if (catta_timeval_compare(a, b) < 0)
+        return - catta_timeval_diff(b, a);
+
+    return ((CattaUsec) a->tv_sec - b->tv_sec)*1000000 + a->tv_usec - b->tv_usec;
+}
+
+struct timeval* catta_timeval_add(struct timeval *a, CattaUsec usec) {
+    CattaUsec u;
+    assert(a);
+
+    u = usec + a->tv_usec;
+
+    if (u < 0) {
+        a->tv_usec = (long) (1000000 + (u % 1000000));
+        a->tv_sec += (long) (-1 + (u / 1000000));
+    } else {
+        a->tv_usec = (long) (u % 1000000);
+        a->tv_sec += (long) (u / 1000000);
+    }
+
+    return a;
+}
+
+CattaUsec catta_age(const struct timeval *a) {
+    struct timeval now;
+
+    assert(a);
+
+    gettimeofday(&now, NULL);
+
+    return catta_timeval_diff(&now, a);
+}
+
+struct timeval *catta_elapse_time(struct timeval *tv, unsigned msec, unsigned jitter) {
+    assert(tv);
+
+    gettimeofday(tv, NULL);
+
+    if (msec)
+        catta_timeval_add(tv, (CattaUsec) msec*1000);
+
+    if (jitter) {
+        static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
+        static int last_rand;
+        static time_t timestamp = 0;
+
+        time_t now;
+        int r;
+
+        now = time(NULL);
+
+        pthread_mutex_lock(&mutex);
+        if (now >= timestamp + 10) {
+            timestamp = now;
+            last_rand = rand();
+        }
+
+        r = last_rand;
+
+        pthread_mutex_unlock(&mutex);
+
+        /* We use the same jitter for 10 seconds. That way our
+         * time events elapse in bursts which has the advantage that
+         * packet data can be aggregated better */
+
+        catta_timeval_add(tv, (CattaUsec) (jitter*1000.0*r/(RAND_MAX+1.0)));
+    }
+
+    return tv;
+}
+