# proof it behaves right, uncomment to see
# $_ = "  '==\\'==' '==5=='  '\\'\\'' '\\'3' '\\'' '1'  '' " x 2;

$n = 40000000;
$_ = "'" . "=" x $n . "'";

my @pos;
while ( /(?<!\\)'/gc ) {
    push @pos, pos;
}

for ( my $i= 0; $i <@pos; $i +=2 ) {
    my $begin = $pos[$i];
    my $end   = $pos[$i+1]-1;
    my $str   = substr $_, $begin, ($end -$begin);
    # check what we have found using test string commented out
    #print "$begin $end '$str'\n";
    print length($str), "\n";
}