[PATCH 08/18] view: speed up /$INBOX/ landing page by 0.5-1.0%

[Eric Wong <e@80x24.org>]

Array lookups and extra arithmetic in Perl is slower than
bumping the internal array offset inside the interpreter.
Fwiw, using: my ($level, $subj) = splice(@extra, 0, 2)
did not result in a performance improvement.
---
 lib/PublicInbox/View.pm | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lib/PublicInbox/View.pm b/lib/PublicInbox/View.pm
index 5fbdd1fa..9846fa47 100644
--- a/lib/PublicInbox/View.pm
+++ b/lib/PublicInbox/View.pm
@@ -1188,9 +1188,9 @@ sub dump_topics {
 
 		my $s = "<a\nhref=\"$href/T/$anchor\">$top_subj</a>\n" .
 			" $ds UTC $n\n";
-		for (my $i = 0; $i < scalar(@extra); $i += 2) {
-			my $level = $extra[$i];
-			my $subj = $extra[$i + 1]; # already normalized
+		while (@extra) {
+			my $level = shift @extra;
+			my $subj = shift @extra; # already normalized
 			$mid = delete $seen->{$subj};
 			my @subj = split(/ /, $subj);
 			my @next_prev = @subj; # full copy