#!/usr/bin/env perl
use strict;
use warnings;
use 5.007003;
use Hash::Util qw(lock_hash unlock_hash lock_keys);
use Storable qw(nfreeze);
# If this looks like a hack, it's probably because it is :-)
sub uuencode_it {
    my ($data, $name) = @_;
    my $frozen = nfreeze $data;
    my $uu = pack 'u', $frozen;
    printf "begin %3o $name\n", ord 'A';
    print $uu;
    print "\nend\n\n";
}
my %hash = (perl=>"rules");
lock_hash %hash;
uuencode_it (\%hash, "Locked hash");
unlock_hash %hash;
lock_keys %hash, 'perl', 'rules';
lock_hash %hash;
uuencode_it (\%hash, "Locked hash placeholder");
unlock_hash %hash;
lock_keys %hash, 'perl';
uuencode_it (\%hash, "Locked keys");
unlock_hash %hash;
lock_keys %hash, 'perl', 'rules';
uuencode_it (\%hash, "Locked keys placeholder");
unlock_hash %hash;
my $utf8 = "\x{DF}\x{100}";
chop $utf8;
uuencode_it (\$utf8, "Short 8 bit utf8 data");
my $utf8b = $utf8;
utf8::encode ($utf8b);
uuencode_it (\$utf8b, "Short 8 bit utf8 data as bytes");
$utf8 x= 256;
uuencode_it (\$utf8, "Long 8 bit utf8 data");
$utf8 = "\x{C0FFEE}";
uuencode_it (\$utf8, "Short 24 bit utf8 data");
$utf8b = $utf8;
utf8::encode ($utf8b);
uuencode_it (\$utf8b, "Short 24 bit utf8 data as bytes");
$utf8 x= 256;
uuencode_it (\$utf8, "Long 24 bit utf8 data");
# Hash which has the utf8 bit set, but no longer has any utf8 keys
my %uhash = ("\x{100}", "gone", "perl", "rules");
delete $uhash{"\x{100}"};
# use Devel::Peek; Dump \%uhash;
uuencode_it (\%uhash, "Hash with utf8 flag but no utf8 keys");
$utf8 = "Schlo\xdf" . chr 256;
chop $utf8;
my $a_circumflex = (ord ('A') == 193 ? "\x47" : "\xe5");
%uhash = (map {$_, $_} 'castle', "ch${a_circumflex}teau", $utf8, "\x{57CE}");
uuencode_it (\%uhash, "Hash with utf8 keys");
lock_hash %uhash;
uuencode_it (\%uhash, "Locked hash with utf8 keys");
my %pre58;
while (my ($key, $val) = each %uhash) {
    # hash keys are always stored downgraded to bytes if possible, with a flag
    # to say "promote back to utf8"
    # Whereas scalars are stored as is.
    utf8::encode ($key) if ord $key > 256;
    $pre58{$key} = $val;
}
uuencode_it (\%pre58, "Hash with utf8 keys for 5.6");