Optimize POD section handling in _parse_fh()

This is one of the hot spots that NYTProf points out for _parse_fh().
Avoiding the negative lookahead and the redundant regexp match for /^=cut/
yields a 10% speedup.

diff --git a/lib/Module/Metadata.pm b/lib/Module/Metadata.pm
index e52a0e2..4fad0f3 100644 (file)
--- a/lib/Module/Metadata.pm
+++ b/lib/Module/Metadata.pm
@@ -456,12 +456,16 @@ sub _parse_fh {
     chomp( $line );
     next if $line =~ /^\s*#/;
 
-    $in_pod = ($line =~ /^=(?!cut)/) ? 1 : ($line =~ /^=cut/) ? 0 : $in_pod;
+    my $is_cut;
+    if ( $line =~ /^=(.{0,3})/ ) {
+      $is_cut = $1 eq 'cut';
+      $in_pod = !$is_cut;
+    }
 
     # Would be nice if we could also check $in_string or something too
     last if !$in_pod && $line =~ /^__(?:DATA|END)__$/;
 
-    if ( $in_pod || $line =~ /^=cut/ ) {
+    if ( $in_pod || $is_cut ) {
 
       if ( $line =~ /^=head\d\s+(.+)\s*$/ ) {
        push( @pod, $1 );