#! perl -slw
use strict;
use vars qw[$LEN $N $SPARSE $CHECK];
use Benchmark qw[cmpthese];

our $str = '17341234';
$str .= '....____' x $SPARSE if $SPARSE;
$str x= ($LEN || 5);

our (@ari, @buk, @dio, @enlil);

my $test = {
    ari1=> q[
      $ari[1] = $str;
      local *_ = do{ \$ari[1] };
      our $i = 0;
      *_ = \substr( $ari[1], $i ) while s[(.)(...)\1(?{ $i = pos() - 4 })][a$2b];
    ],
    buk1=> q[
      $buk[1] = $str;
      substr($buk[1], $_, 5) =~ s[(.)(...)\1][a$2b] for 0 .. length ($buk[1]);
    ],
    buk2=> q[
      $buk[2] = $str;
      for( 0 .. length($buk[2]) ) { substr($buk[2], $_, 5) =~ s[(.)(...)\1][a$2b] };
    ],
    buk3=> q[
      $buk[3] =  $str;
      my $i;
      $i = pos($buk[3])-5
      , substr( $buk[3], $i, 5) =~ s[(.)(...)\1][a$2b]
      , pos($buk[3]) = $i
              while $buk[3] =~ m[(.)(...)\1]g;
    ],
    dio1=> q[
      $dio[1] = $str;
      1 while $dio[1] =~ s/(.)(...)\1/a$2b/;
    ],
    dio2=> q[
      $dio[2] = $str;
      $r = 0;
      1 while substr($dio[2],$r) =~ s/(.)(...)\1(?{$r = pos() - 3})/a$2b/;
    ],
    dio3=> q[
      $dio[3] = $str;
      $r = 0;
      1 while substr($dio[3],$r) =~ s[(.)(...)\1(?{$r +=pos() - 4})][a$2b];
    ],
    enlil=> q[{
      $enlil[1] = $str;
      our $i = 0;
      pos($enlil[1]) = $i - 4
        while $enlil[1] =~ s[\G (.*?) (.) (...) \2 (?{ $i = pos() })  ]
                            [ defined $1 ? $1.'a'.$3.'b' : 'a'.$3.'b' ]ex;
    }],
};

# A bug with Lvalue refs cause Ari1 to segfault if executed more than twice!
delete $test->{ari1}, $ari[1] = 'Test not performed'    if $N < 1 or $N > 2;

cmpthese( $N||-3, $test );

exit unless $CHECK;
print "
Ari1:$ari[1]
buk1:$buk[1]
buk2:$buk[2]
buk3:$buk[3]
dio1:$dio[1]
dio2:$dio[2]
dio3:$dio[3] 
enll:$enlil[1]
";

__END__