+
+# find the correct local_data directory
+# basically, if there is a local_data directory with this filename and it is younger than the
+# equivalent one in the (system) data directory then return that name rather than the system one
+sub localdata
+{
+ my $ifn = shift;
+ my $ofn = "$root/local_data/$ifn";
+ my $tfn;
+
+ if (-e "$root/local_data") {
+ $tfn = "$main::data/$ifn";
+ if ((-e $tfn) && (-e $ofn)) {
+ $ofn = $tfn if -M $ofn < -M $tfn;
+ }
+ else {
+ $ofn = $tfn if -e $tfn;
+ }
+ }
+
+ return $ofn;
+}
+# measure the time taken for something to happen; use Time::HiRes qw(gettimeofday tv_interval);
+sub _diffms
+{
+ my $ta = shift;
+ my $tb = shift || [gettimeofday];
+ my $a = int($ta->[0] * 1000) + int($ta->[1] / 1000);
+ my $b = int($tb->[0] * 1000) + int($tb->[1] / 1000);
+ return $b - $a;
+}
+