- $str =~ m/^(.{0,$len}[^ \/\-_:\.@]{0,$add_len})(.*)/;
- my $body = $1;
- my $tail = $2;
- if (length($tail) > 4) {
- $tail = " ...";
- $body =~ s/&[^;]*$//; # remove chopped character entities
+ # remove chopped character entities entirely
+
+ # when chopping in the middle, distribute $len into left and right part
+ # return early if chopping wouldn't make string shorter
+ if ($where eq 'center') {
+ return $str if ($len + 5 >= length($str)); # filler is length 5
+ $len = int($len/2);
+ } else {
+ return $str if ($len + 4 >= length($str)); # filler is length 4
+ }
+
+ # regexps: ending and beginning with word part up to $add_len
+ my $endre = qr/.{$len}\w{0,$add_len}/;
+ my $begre = qr/\w{0,$add_len}.{$len}/;
+
+ if ($where eq 'left') {
+ $str =~ m/^(.*?)($begre)$/;
+ my ($lead, $body) = ($1, $2);
+ if (length($lead) > 4) {
+ $body =~ s/^[^;]*;// if ($lead =~ m/&[^;]*$/);
+ $lead = " ...";
+ }
+ return "$lead$body";
+
+ } elsif ($where eq 'center') {
+ $str =~ m/^($endre)(.*)$/;
+ my ($left, $str) = ($1, $2);
+ $str =~ m/^(.*?)($begre)$/;
+ my ($mid, $right) = ($1, $2);
+ if (length($mid) > 5) {
+ $left =~ s/&[^;]*$//;
+ $right =~ s/^[^;]*;// if ($mid =~ m/&[^;]*$/);
+ $mid = " ... ";
+ }
+ return "$left$mid$right";
+
+ } else {
+ $str =~ m/^($endre)(.*)$/;
+ my $body = $1;
+ my $tail = $2;
+ if (length($tail) > 4) {
+ $body =~ s/&[^;]*$//;
+ $tail = "... ";
+ }
+ return "$body$tail";