my @RE = (qr/[[:lower:]]/, qr/[[:upper:]]/, qr/[0-9]/, qr/[^[:alnum:]]
+/);
sub check {
    local ($_) = @_;
    my $length = length;
    return if $length < 8;
    return if $length < 12 && (! /$RE[0]/ || ! /$RE[1]/ || ! /$RE[2]/ 
+|| ! /$RE[3]/);
    return if $length < 16 && (! /$RE[0]/ || ! /$RE[1]/ || ! /$RE[2]/)
+;
    return if $length < 20 && (! /$RE[0]/ || ! /$RE[1]/);
    return 1
}

[download]

Tested against the tests from Re: Efficient way to verify scalar contents (updated x3) (haukex++).

Update: Or, if you want to abstract away the repeating $RE[...]

use List::Util qw{ any };

my @RE = (qr/[[:lower:]]/, qr/[[:upper:]]/, qr/[0-9]/, qr/[^[:alnum:]]
+/);
sub check {
    my ($password) = @_;
    my $length = length $password;
    return if $length < 8;
    return if $length < 12 && any { $password !~ $RE[$_] } 0 .. 3;
    return if $length < 16 && any { $password !~ $RE[$_] } 0 .. 2;
    return if $length < 20 && any { $password !~ $RE[$_] } 0 .. 1;
    return 1
}

[download]

map{substr$_->[0],$_->[1]||0,1}[\*||{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^*ARGV,3]

In reply to Re: Efficient way to verify scalar contents by choroba
in thread Efficient way to verify scalar contents by x_stream3m

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.