From: Mischa POSLAWSKY <perl@shiar.org>
Date: Thu, 12 Nov 2009 17:54:19 +0000 (+0100)
Subject: XXX: after context
X-Git-Url: http://git.shiar.nl/perl/list-index.git/commitdiff_plain/ab9917512865cf7070b364a1b0f07f32a3b49e3f

XXX: after context
---

diff --git a/lib/List/Index.pm b/lib/List/Index.pm
index 574613e..47ef0da 100644
--- a/lib/List/Index.pm
+++ b/lib/List/Index.pm
@@ -28,16 +28,33 @@ sub ranges {
 	while ($offset < @$self) {
 		my $link = substr $self->[$offset], 0, $length;
 		if ($context) {
-			# 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++;
+			{
+				# 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, $trim;
+				}
 			}
-			# truncate link upto where the earlier value starts to differ
-			substr($link, $trim) = '' unless $trim > length $link;
 		}
 
 		push @links, [$link];
diff --git a/t/10-ranges.t b/t/10-ranges.t
index 2348fca..66edf76 100644
--- a/t/10-ranges.t
+++ b/t/10-ranges.t
@@ -25,11 +25,11 @@ is_deeply($index->ranges({pagesize => @uniform / 2.1}), [map { [split /-/, $_, 2
 {
 ok(my $index = List::Index->new(['aa'..'zz', 1..193]), 'non-alphabetic values (uniform)');
 is_deeply($index->ranges, [map { [split /-/, $_, 2] } qw(
-	-. ..-. .. ...-.
-	a-bv bw-dr ds-fn fo-hk hl-jg jh-k l-m n-ov ow-qr qs-sn so-uk ul-wg wh-x y-
+	-. . . .
+	a-b c-dr ds-fn fo-hk hl-jg jh-k l-m n-o p-qr qs-sn so-uk ul-wg wh-x y-
 )], 'default ranges');
 is_deeply($index->ranges({pagesize => 300}), [map { [split /-/, $_, 2] } qw(
-	-c d-ov ow-
+	-c d-o p-
 )], 'large pagesize');
 }
 
@@ -38,13 +38,13 @@ ok(my $index = List::Index->new([qw(
 	baa1 baa2  baa3 baaa  bbc cbc  daaa ea  eaaa zed
 )]), 'variable length values');
 is_deeply($index->ranges({pagesize => 2, context => 0}), [
-	map { [split /-/, $_, 2] } qw(-baa baa.-bbb bbc-daa. daaa-eaa. eaaa-)
+	map { [split /-/, $_, 2] } qw(-baa. baa.-bbb bbc-daa. daaa-eaa. eaaa-)
 ], 'no context');
 is_deeply($index->ranges({pagesize => 2}), [
-	map { [split /-/, $_, 2] } qw(-baa baa.-ba bb-c d-ea. eaa-)
+	map { [split /-/, $_, 2] } qw(-a b c d-ea. eaa-)
 ], 'default context');  # context should be 1
 is_deeply($index->ranges({pagesize => 2, context => 2}), [
-	map { [split /-/, $_, 2] } qw(-a b-ba bb-c d e-)
+	map { [split /-/, $_, 2] } qw(-a b-c d-c d e-)
 ], 'overlap');  # first item equals second due to large context
 is_deeply($index->ranges({pagesize => 2, length => 1}), [
 	map { [split /-/, $_, 2] } qw(-a b-a b-c d e-)