From 1c331324738bb8ca05889f1a7baa5e1b40595d38 Mon Sep 17 00:00:00 2001
From: Mischa POSLAWSKY <perl@shiar.org>
Date: Fri, 13 Nov 2009 15:59:30 +0100
Subject: [PATCH] lookbehind before context, so page increment is _upto_
 context rows

---
 lib/List/Index.pm | 4 ++--
 t/10-ranges.t     | 6 +++---
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/lib/List/Index.pm b/lib/List/Index.pm
index 5b46313..4a21189 100644
--- a/lib/List/Index.pm
+++ b/lib/List/Index.pm
@@ -28,9 +28,9 @@ sub ranges {
 	while ($offset < @$self) {
 		my $link = substr $self->[$offset], 0, $length;
 		if ($context) {
-			{
+			if ($offset > $context - 1) {
 				# take a value slightly before the current offset
-				my $before = $offset > $context ? $self->[$offset - $context] : '.';
+				my $before = $self->[$offset - $context - 1];
 				# see how much of it matches the current link
 				my $trim = 1;
 				for my $match (split //, $before) {
diff --git a/t/10-ranges.t b/t/10-ranges.t
index 1ec5d60..ef292b1 100644
--- a/t/10-ranges.t
+++ b/t/10-ranges.t
@@ -29,7 +29,7 @@ subtest 'uniform alphanumeric' => sub {
 		.-bp bq-dm dn-fi fj-hf hg-i j-k l-m n-os ot-qp qq-sm sn-uj uk-wf wg-x y-
 
 	)], 'default ranges');
-	is_deeply($index->ranges({pagesize => 300}), [qw(-c d-o p-)], 'large pagesize');
+	is_deeply($index->ranges({pagesize => 300}), [qw(-c d-n o-)], 'large pagesize');
 };
 
 subtest 'context' => sub {
@@ -41,12 +41,12 @@ subtest 'context' => sub {
 		qw(-baa. baa.-bbb bbc-daa. daaa-eaa. eaaa-)
 	], 'no context');
 	is_deeply($index->ranges({pagesize => 2}), [
-		qw(-a b c d-ea. eaa-)
+		qw(-a b c d e-)
 	], 'default context');  # context should be 1
 	is_deeply($index->ranges({pagesize => 2, context => 2}), [
 		qw(-a b-c d e-)
 	], 'overlap');  # first item equals second due to large context
-	is_deeply($index->ranges({pagesize => 2, length => 1}), [
+	is_deeply($index->ranges({pagesize => 2, context => 0, length => 1}), [
 		qw(-a b-c d e-)
 	], 'single char');
 
-- 
2.30.0