my $length = $options->{length } || 4;
my $pages = $options->{pages } || 1 + int $#$self / $pagesize;
- $pagesize = @$self / $pages;
- my $offset = $pagesize + .5;
+ $pagesize = $pages >= $#$self ? 1 : @$self / $pages;
+ my $lookbehind = -$context;
+ my $lookahead = $context;
+
my @links = ('');
- while ($offset < @$self) {
+ for (my $offset = $pagesize + .5; $offset < @$self; $offset += $pagesize) {
my $link = substr $self->[$offset], 0, $length;
if ($context) {
- {
- # take a value slightly before the current offset
- my $before = $offset > $context ? $self->[$offset - $context] : '.';
+ my $penalty = 0;
+ # take a value slightly before the current offset
+ if ((my $before = $offset + $lookbehind) > 0) {
# see how much of it matches the current link
my $trim = 1;
- for my $match (split //, $before) {
+ for my $match (split //, $self->[$before - 1]) {
scalar $link =~ /\G\Q$match/g or last;
$trim++;
}
# truncate link upto where the earlier value starts to differ
- substr($link, $trim) = '' unless $trim > length $link;
+ if ($trim < length $link) {
+ substr($link, $trim) = '';
+ for (reverse $before .. $offset) {
+ $self->[$offset - $penalty] =~ /^\Q$link/ or last;
+ $penalty++;
+ }
+ }
}
- if ($offset + $context < $#$self) {
- # take a value after the current offset
- my $after = $self->[$offset + $context];
+ $lookbehind = -$context;
+
+ # take a value after the current offset
+ if ((my $after = $offset + $lookahead) < $#$self) {
# see how much of it matches the current link
my $trim = 1;
- for my $match (split //, $after) {
+ for my $match (split //, $self->[$after]) {
scalar $link =~ /\G\Q$match/g or last;
$trim++;
}
# use this link if it's shorter
if ($trim < length $link) {
- $link = substr $after, 0, $trim;
+ $link = substr $self->[$after], 0, $trim;
+ # advance lookbehind offset on the next page
+ $penalty = 0;
+ for ($offset .. $after) {
+ last if $self->[$_] =~ /^\Q$link/;
+ $lookbehind++;
+ }
}
}
+
+ $lookahead = $context - $penalty;
}
push @links, $link;
- $offset += $pagesize;
}
use List::MoreUtils 'uniq';