X-Git-Url: http://git.shiar.net/gitweb.cgi/perl/list-index.git/blobdiff_plain/d61e8685992586de85f6b7b58fee20f15c8111b0..356b069f60818a6ef5f0f8cf97a78924675c2c5b:/lib/List/Index.pm?ds=inline
diff --git a/lib/List/Index.pm b/lib/List/Index.pm
index 6a818bb..bf4e04d 100644
--- a/lib/List/Index.pm
+++ b/lib/List/Index.pm
@@ -6,7 +6,7 @@ use warnings;
use Exporter 'import';
-our $VERSION = '1.00';
+our $VERSION = '1.01';
our @EXPORT_OK = qw(rangematch);
sub new {
@@ -23,18 +23,38 @@ sub ranges {
my $pages = $options->{pages } || 1 + int $#$self / $pagesize;
$pagesize = @$self / $pages;
- my $offset = 0;
- my @links;
+ my $offset = $pagesize;
+ my @links = (['']);
while ($offset < @$self) {
my $link = substr $self->[$offset], 0, $length;
if ($context) {
- my $trim = 1;
- my $before = $offset > $context ? $self->[$offset - $context] : '';
- for my $match (split //, $before) {
- scalar $link =~ /\G\Q$match/g or last;
- $trim++;
+ {
+ # take a value slightly before the current offset
+ my $before = $offset > $context ? $self->[$offset - $context] : '.';
+ # see how much of it matches the current link
+ my $trim = 1;
+ for my $match (split //, $before) {
+ 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 $link;
+ }
+
+ if ($offset + $context < $#$self) {
+ # take a value after the current offset
+ my $after = $self->[$offset + $context];
+ # see how much of it matches the current link
+ my $trim = 1;
+ for my $match (split //, $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, $trim;
+ }
}
- substr($link, $trim) = '' unless $trim > length $link;
}
push @links, [$link];
@@ -43,8 +63,8 @@ sub ranges {
for my $i (0 .. $#links - 1) {
my ($link, $lastchar) = $links[$i + 1]->[0] =~ /(.*)(.)/;
- $link .= $lastchar eq '.' ? 'z' : chr( ord($lastchar) - 1 )
- unless $lastchar eq 'a';
+ $link .= $lastchar le 'a' ? '.' : chr( ord($lastchar) - 1 );
+ next if $link eq $links[$i]->[0] and $i;
$links[$i]->[1] = $link;
}
$links[-1]->[1] = '';
@@ -59,33 +79,54 @@ sub rangematch {
my @allow;
if (length $s1) {
+ if (length $s2) {
+ $s1 le $s2 or $s1 =~ /^\Q$s2/ or return undef;
+ }
+
my $prefix = '';
- my $c1;
+ my $char;
for my $i (0 .. length($s1) - 1) {
- $c1 = substr $s1, $i, 1;
- my $c2 = length $s2 <= $i ? undef : substr $s2, $i, 1;
- my $next = $i + 1 >= length($s1) ? $c1 : chr( ord($c1) + 1 );
- $next le $c2 or next if defined $c2;
- my $last = defined $c2 && $i == 0 ? chr( ord($c2) - (length $s2 > 1) ) : 'z';
+ $char = substr $s1, $i, 1;
+ my $next = $char;
+ $next = chr( ord($char) + 1 ) if length $s1 > $i + 1;
+ my $last = 'z';
+ if (length $s2 > $i) {
+ if ($s2 =~ /^\Q$prefix/) {
+ $last = substr $s2, $i, 1;
+ next if $char eq $last;
+ $last = chr( ord($last) - (length $s2 > 1) );
+ next if $next gt $last;
+ }
+ }
push @allow, $prefix."[$next-$last]";
}
continue {
- $prefix .= $c1;
+ $prefix .= $char;
}
}
if (length $s2) {
my $prefix = '';
+ my $char;
for my $i (0 .. length($s2) - 1) {
- my $c1 = length $s1 <= $i ? undef : substr $s1, $i, 1;
- my $c2 = substr $s2, $i, 1;
+ $char = substr $s2, $i, 1;
my $last = 'z';
- push @allow, "$prefix(?![$c2-$last])"
+ if (length $s1 > $i) {
+ my $c1 = substr $s1, $i, 1;
+ if ($s1 =~ /^\Q$prefix/) {
+ next if $c1 le $char;
+ }
+ }
+ push @allow, $prefix."(?![$char-$last])"
if $i or $s1 eq '';
- $prefix .= $c2;
}
+ continue {
+ $prefix .= $char;
+ }
+
push @allow, $prefix
- unless length $s1 > length $s2 or length $s1 != 0 && length $s2 == 1; #TODO
+ if $s2 =~ /^\Q$prefix/ and $s1 le $s2
+ and not (length $s2 == 1 && length $s1 >= length $s2 && $s1 ne $s2);
}
my $match = sprintf @allow <= 1 ? '%s' : '(?:%s)', join('|', @allow);
@@ -105,7 +146,11 @@ List::Index - Paginate alphabetic entries by finding minimal prefixes
use List::Index;
my $index = List::Index->new(\@values);
my @pages = $index->ranges({pagesize => 50});
- printf '%1$s ', @$_ for @pages;
+ printf '%1$s ', @$_ for @pages;
+
+ use List::Index 'rangematch';
+ my $limit = rangematch('b-bmq'); # matches prefix like 'baa'..'bmq'
+ @results = grep { $limit } @results;
=head1 DESCRIPTION