my $pagesize = $options->{pagesize} || 50;
my $context = $options->{context } // 1 + ($pagesize >> 4);
my $length = $options->{length } || 4;
- my $pages = $options->{pages } || 1 + int $#rows / $pagesize;
+ my $pages = $options->{pages } || 1 + int($#rows / $pagesize);
- $pagesize = $pages >= $#rows ? 1 : @rows / $pages;
- my $lookbehind = -$context;
- my $lookahead = $context;
+ $pagesize = $pages >= @rows ? 1 : @rows / $pages;
+ my $shrunk = 0;
+ my $enlarged = 0;
my @links = ('');
for (my $offset = $pagesize + .5; $offset < @rows; $offset += $pagesize) {
my $link = substr $rows[$offset], 0, $length;
if ($context) {
- my $penalty = 0;
+ my $lookbehind = -$context + $shrunk;
+ my $lookahead = $context - $enlarged;
+ $shrunk = $enlarged = 0;
+
# take a value slightly before the current offset
if ((my $before = $offset + $lookbehind) > 0) {
# see how much of it matches the current link
# truncate link upto where the earlier value starts to differ
if ($trim < length $link) {
substr($link, $trim) = '';
- for (reverse $before .. $offset) {
- $rows[$offset - $penalty] =~ /^\Q$link/ or last;
- $penalty++;
+ for (reverse $before .. $offset - 1) {
+ $rows[$_] =~ /^\Q$link/ or last;
+ $enlarged++;
}
}
}
- $lookbehind = -$context;
-
# take a value after the current offset
if ((my $after = $offset + $lookahead) < $#rows) {
# see how much of it matches the current link
my $trim = 1;
+ pos $link = 0;
for my $match (split //, $rows[$after]) {
scalar $link =~ /\G\Q$match/g or last;
$trim++;
}
# use this link if it's shorter
if ($trim < length $link) {
- $link = substr $rows[$after], 0, $trim;
- # advance lookbehind offset on the next page
- $penalty = 0;
- for ($offset .. $after) {
- last if $rows[$_] =~ /^\Q$link/;
- $lookbehind++;
+ $enlarged = 0;
+ for ($offset + 1 .. $after) {
+ my $prefix = substr $rows[$_], 0, $trim;
+ # advance lookbehind offset on the next page
+ $shrunk++;
+ next if $link =~ /^\Q$prefix/;
+ $link = $prefix;
+ last;
}
}
}
-
- $lookahead = $context - $penalty;
}
push @links, $link unless $links[-1] eq $link;