use Exporter 'import';
-our $VERSION = '1.01';
+our $VERSION = '1.02';
our @EXPORT_OK = qw(rangematch);
sub new {
- my ($class, $values) = @_;
- bless [sort map { s/[^a-z]/./g; $_ } @$values], $class;
+ my ($class, $options) = @_;
+ $options ||= {};
+ bless $options, $class;
}
sub ranges {
my $self = shift;
+ my @rows = sort map { s/[^a-z]/./g; $_ } @{ shift() };
my $options = shift || {};
+ $options->{$_} //= $self->{$_} for keys %$self;
+
my $pagesize = $options->{pagesize} || 50;
my $context = $options->{context } // 1 + ($pagesize >> 4);
my $length = $options->{length } || 4;
- my $pages = $options->{pages } || 1 + int $#$self / $pagesize;
+ my $pages = $options->{pages } || 1 + int $#rows / $pagesize;
+
+ $pagesize = $pages >= $#rows ? 1 : @rows / $pages;
+ my $shrunk = 0;
+ my $enlarged = 0;
- $pagesize = @$self / $pages;
- my $offset = $pagesize + .5;
- my $lookbehind = -$context;
- my $lookahead = $context;
my @links = ('');
- while ($offset < @$self) {
- my $link = substr $self->[$offset], 0, $length;
+ 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
my $trim = 1;
- for my $match (split //, $self->[$before - 1]) {
+ for my $match (split //, $rows[$before - 1]) {
scalar $link =~ /\G\Q$match/g or last;
$trim++;
}
# truncate link upto where the earlier value starts to differ
if ($trim < length $link) {
substr($link, $trim) = '';
- for (reverse $before .. $offset) {
- $self->[$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) < $#$self) {
+ if ((my $after = $offset + $lookahead) < $#rows) {
# see how much of it matches the current link
my $trim = 1;
- for my $match (split //, $self->[$after]) {
+ 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 $self->[$after], 0, $trim;
- # advance lookbehind offset on the next page
- $penalty = 0;
- for ($offset .. $after) {
- last if $self->[$_] =~ /^\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;
- $offset += $pagesize;
+ push @links, $link unless $links[-1] eq $link;
}
- use List::MoreUtils 'uniq';
- @links = uniq @links;
+ # add range end to each link
for my $i (0 .. $#links - 1) {
- my ($link, $lastchar) = $links[$i + 1] =~ /(.*)(.)/;
- $link .= $lastchar le 'a' ? '.' : chr( ord($lastchar) - 1 );
- next if $link eq $links[$i] and $i;
- $links[$i] .= '-'.$link;
+ # end at start of next value with the last character decremented
+ my $next = $links[$i + 1];
+ $next =~ s{(.)$}{ $1 le 'a' ? '.' : chr( ord($1) - 1 ) }e;
+ # amend range if it's ahead
+ $links[$i] .= '-'.$next unless $next eq $links[$i];
}
+ # final value takes the rest
$links[-1] .= '-';
return \@links;
=head1 SYNOPSIS
use List::Index;
- my $index = List::Index->new(\@values);
- my @pages = $index->ranges({pagesize => 50});
+ my $index = List::Index->new({ pagesize => 50 });
+ my @pages = $index->ranges(\@values);
say "<a href='?q=$_'>$_</a>" for @pages;
use List::Index 'rangematch';