forked from jbagg/QtZeroConf
124 lines
2.9 KiB
C
124 lines
2.9 KiB
C
/***
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This file is part of avahi.
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avahi is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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avahi is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
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Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with avahi; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
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USA.
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***/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#include <pthread.h>
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#include <stdlib.h>
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#include <assert.h>
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#include "timeval.h"
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int avahi_timeval_compare(const struct timeval *a, const struct timeval *b) {
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assert(a);
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assert(b);
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if (a->tv_sec < b->tv_sec)
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return -1;
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if (a->tv_sec > b->tv_sec)
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return 1;
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if (a->tv_usec < b->tv_usec)
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return -1;
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if (a->tv_usec > b->tv_usec)
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return 1;
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return 0;
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}
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AvahiUsec avahi_timeval_diff(const struct timeval *a, const struct timeval *b) {
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assert(a);
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assert(b);
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if (avahi_timeval_compare(a, b) < 0)
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return - avahi_timeval_diff(b, a);
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return ((AvahiUsec) a->tv_sec - b->tv_sec)*1000000 + a->tv_usec - b->tv_usec;
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}
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struct timeval* avahi_timeval_add(struct timeval *a, AvahiUsec usec) {
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AvahiUsec u;
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assert(a);
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u = usec + a->tv_usec;
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if (u < 0) {
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a->tv_usec = (long) (1000000 + (u % 1000000));
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a->tv_sec += (long) (-1 + (u / 1000000));
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} else {
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a->tv_usec = (long) (u % 1000000);
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a->tv_sec += (long) (u / 1000000);
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}
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return a;
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}
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AvahiUsec avahi_age(const struct timeval *a) {
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struct timeval now;
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assert(a);
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gettimeofday(&now, NULL);
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return avahi_timeval_diff(&now, a);
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}
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struct timeval *avahi_elapse_time(struct timeval *tv, unsigned msec, unsigned jitter) {
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assert(tv);
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gettimeofday(tv, NULL);
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if (msec)
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avahi_timeval_add(tv, (AvahiUsec) msec*1000);
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if (jitter) {
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static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
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static int last_rand;
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static time_t timestamp = 0;
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time_t now;
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int r;
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now = time(NULL);
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pthread_mutex_lock(&mutex);
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if (now >= timestamp + 10) {
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timestamp = now;
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last_rand = rand();
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}
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r = last_rand;
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pthread_mutex_unlock(&mutex);
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/* We use the same jitter for 10 seconds. That way our
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* time events elapse in bursts which has the advantage that
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* packet data can be aggregated better */
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avahi_timeval_add(tv, (AvahiUsec) (jitter*1000.0*r/(RAND_MAX+1.0)));
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}
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return tv;
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}
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