I'm parsing a dhcpd.conf file and expect the number of entires to reach probably 1000 at long turn.. At the moment I don't look so much at speed, but will need it may be !!!
At the moment there is only one case when I will resolv-all entiries (mac->name)...

my code up to the moment is :

......

sub parse {
 my $self = shift;
  #parse the classes
 my @clases = $$self{_data} =~ /class\s+?"(.+?)"\s+?\{.*?=\s*(.+?)\s*;
+/gs;
 while ($#clases > 0) {
    $$self{_clases}{pop @clases} = pop @clases;
 }
 
 my @hosts = $$self{_data} =~ /
    host\s*(.+?)\s*\{.*?
     filename\s*"(.+?)"\s*;.*?
     ethernet\s*(.+?)\s*;.*?
     fixed-address\s*(.+?)\s*;
 /xgs; 
 while ($#hosts > 0) {
    my $h = shift @hosts;
   ($$self{_hosts}{$h}{file}, $$self{_hosts}{$h}{mac}, 
     $$self{_hosts}{$h}{ip})  = splice @hosts,0,3;
 }
}

sub name2 {
 my ($self, $name, $to) = @_;
 $$self{_hosts}{$name}{$to}
}

1;
[download]

One thing on which i would like to hear your comment is the while cycles ... did u see "my $h", if i try this :

   (my $h, $$self{_hosts}{$h}{file}, $$self{_hosts}{$h}{mac}, 
     $$self{_hosts}{$h}{ip})  = splice @hosts,0,4;
[download]

it wont work... not a big deal but it is interesting to know why ?