#!/usr/bin/perl
use warnings;
use strict;

sub regex_pos {
    my ($string) = @_;
    $string =~ /[^ \t]/g;
    return pos($string) - 1
}

sub tr_pos {
    my ($string) = @_;
    (my $tr = $string) =~ tr/ \t/!!/c;
    return index $tr, '!'
}

for my $s ("  \t x  ", "\t\t\t\t\t\t                  \xff...\t ") {
    regex_pos($s) == tr_pos($s) or die;
}

use Benchmark qw{ cmpthese };

my $s = ' ' x 200 . "\t" x 200 . "\x01" . " " x 200;
cmpthese(-3, {
    regex => sub { regex_pos($s) },
    tr    => sub { tr_pos($s)    },
});