+sub valid_isodate
+{
+ my $date = shift;
+ my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime(time);
+
+ return sprintf('%04d-%02d-%02d', $year+1900, $mon+1, $mday) unless defined $date;
+
+ if ($date =~ /^(\d+)\.(\d+)\.?$/) {
+ if ($mon == 0 && $2 > 9) {
+ $date = sprintf('%04d-%02d-%02d', $year+1900-1, $2, $1);
+ } else {
+ $date = sprintf('%04d-%02d-%02d', $year+1900, $2, $1);
+ }
+ } elsif ($date =~ /^(\d+)\.(\d+)\.(\d+)?$/) {
+ if (length $3 == 2) {
+ $date = sprintf('20%02d-%02d-%02d', $3, $2, $1);
+ } else {
+ $date = sprintf('%04d-%02d-%02d', $3, $2, $1);
+ }
+ } elsif ($date !~ /^(\d+)-(\d+)-(\d+)$/) {
+ return undef;
+ }
+ return $date;
+}
+