+
+# expects either an array reference or two times (in the correct order [start, end])
+sub difft
+{
+ my $b = shift;
+ my $adds = shift;
+
+ my $t;
+ if (ref $b eq 'ARRAY') {
+ $t = $b->[1] - $b->[0];
+ } else {
+ if ($adds && $adds =~ /^\d+$/ && $adds >= $b) {
+ $t = $adds - $b;
+ $adds = shift;
+ } else {
+ $t = $main::systime - $b;
+ }
+ }
+ return '-(ve)' if $t < 0;
+ my ($y,$d,$h,$m,$s);
+ my $out = '';
+ $y = int $t / (86400*365);
+ $out .= sprintf ("%s${y}y", $adds?' ':'') if $y;
+ $t -= $y * 86400 * 365;
+ $d = int $t / 86400;
+ $out .= sprintf ("%s${d}d", $adds?' ':'') if $d;
+ $t -= $d * 86400;
+ $h = int $t / 3600;
+ $out .= sprintf ("%s${h}h", $adds?' ':'') if $h;
+ $t -= $h * 3600;
+ $m = int $t / 60;
+ $out .= sprintf ("%s${m}m", $adds?' ':'') if $m;
+ if ($d == 0 && $adds || $adds == 2) {
+ $s = int $t % 60;
+ $out .= sprintf ("%s${s}s", $adds?' ':'') if $s;
+ $out ||= sprintf ("%s0s", $adds?' ':'');
+ }
+ $out = '0s' unless length $out;
+ return $out;
+}
+
+# print an array ref of difft refs
+sub parraydifft
+{
+ my $r = shift;
+ my $out = '';
+ for (@$r) {
+ my $s = $_->[2] ? "($_->[2])" : '';
+ $out .= sprintf "%s=%s$s, ", atime($_->[0]), difft($_->[0], $_->[1]);
+ }
+ $out =~ s/,\s*$//;
+ return $out;
+}
+
+sub basecall
+{
+ my ($r) = $_[0] =~ m{^((?:[\w\d]+/)?[\w\d]+(?:/[\w\d]+)*)(?:-\d+)?(?:-\#)?$};
+ return $r;
+}
+
+sub normalise_call
+{
+ my ($c, $ssid) = $_[0] =~ m|^((?:[\w\d]+/)?[\d\w]+(?:/[\w\d]+)*)(?:-(\d+))?(?:-\#)?$|;
+ my $ncall = $c;
+ $ssid += 0;
+ $ncall .= "-$ssid" if $ssid;
+ return $ncall;
+}
+
+sub is_numeric
+{
+ return $_[0] =~ /^[\.\d]+$/;
+}