add LRU caching

[spider.git] / perl / Chain.pm

diff --git a/perl/Chain.pm b/perl/Chain.pm
index cb3a2be83feaf27eabf182ae5be8b84e058aea27..8afd62f05b6a25ad146b69aaca08f4518d2ca582 100644 (file)
--- a/perl/Chain.pm
+++ b/perl/Chain.pm
@@ -30,10 +30,11 @@ sub setcheck
 # constructor                  
 sub new
 {
-       my $name = shift;
-       my $ref = shift;
+       my $pkg = shift;
+       my $name = ref $pkg || $pkg;
+
        my $self = [];
-       push @$self, $self, $self, $ref;
+       push @$self, $self, $self, @_;
        return bless $self, $name;
 }
 
@@ -44,7 +45,7 @@ sub ins
        
        $docheck && _check($p);
        
-       my $q = ref $ref && $ref->isa('Chain') ? $ref : new Chain $ref;
+       my $q = ref $ref && $ref->isa('Chain') ? $ref : Chain->new($ref);
        $q->[PREV] = $p->[PREV];
        $q->[NEXT] = $p;
        $p->[PREV]->[NEXT] = $q;
@@ -68,9 +69,10 @@ sub del
        
        $docheck && _check($p);
        
-       $p->[PREV]->[NEXT] = $p->[NEXT];
+       my $q = $p->[PREV]->[NEXT] = $p->[NEXT];
        $p->[NEXT]->[PREV] = $p->[PREV];
-       return $p->[PREV];
+       $p->[NEXT] = $p->[PREV] = undef;
+       return $q;
 }
 
 # Is this chain empty?
@@ -104,7 +106,7 @@ sub prev
        
        $docheck && _check($base);
        
-       return $base->[NEXT] == $base ? undef : $base->[PREV] unless $p; 
+       return $base->[PREV] == $base ? undef : $base->[PREV] unless $p; 
        
        $docheck && _check($p);
        
@@ -161,9 +163,9 @@ Chain - Double linked circular chain handler
 =head1 SYNOPSIS
 
   use Chain;
-  $base = new Chain;
-  $p->ins($ref);
-  $p->add($ref);
+  $base = new Chain [$obj];
+  $p->ins($ref [,$obj]);
+  $p->add($ref [,$obj]);
   $ref = $p->obj or $p->obj($ref);
   $q = $base->next($p);
   $q = $base->prev($p);