bugfix: hokey long interval calculation.

The intent is to have a clock which measures milliseconds and
wraps around from 1000000000 (billion) back to zero, fitting
into 32 bits. The now - lastttime calculation must be done
modulo a billion. The difference could be negative because
of the wrap; to ensure we get a positive residue, we add a
billion.

1 files changed, 3 insertions, 1 deletions

diff --git a/pw.c b/pw.c
index 7f98136..44d0faa 100644
--- a/pw.c
+++ b/pw.c
@@ -1571,7 +1571,9 @@ int main(int argc, char **argv)
 
         gettimeofday(&tv, NULL);
         now = tv.tv_sec % 1000000 * 1000 + tv.tv_usec / 1000;
-        if (lasttime == -1 || now - lasttime > long_interval) {
+        if (lasttime == -1 ||
+            (now + 1000000000 - lasttime) % 1000000000 > long_interval)
+        {
           if ((pw.stat & stat_dirty) && pw.nlines == pw.maxlines)
             force = 1;
           lasttime = now;