#!/usr/bin/perl -w
use Benchmark;

my $string = "CCATGNNNTAACCNNATGNNTAGCC" x 10000;

timethese(10, {
              'matchamp' => sub {matchamp($string)},
              'matchpar' => sub {matchpar($string)},
});

sub matchamp {
  my $string = shift;
  my $matchlen = 0;
  while($string =~ /[AG]TG.*?[AG][AG]/g) {
    $matchlen += length($&); # Actually reference $& to keep Perl from cheating
  }
  return $matchlen;
}

sub matchpar {
  my $string = shift;
  my $matchlen = 0;
  while ( $string =~ /([AG]TG.*?T[AG][AG])/g ) {
    $matchlen += length($1); # Reference $1, for fairness
  }
  return $matchlen;
}