Character Encoding and Safe Queries

$decimal = 3456;
$hex = &dec2hex($decimal);
print "decimal $decimal = '$hex'\n";

sub dec2hex($) { return sprintf("%lx", $_[0]) }

my $hex = &iso2hex('ABC');
print "iso 'ABC' = '$hex'\n";

sub iso2hex($) {
	my $hex = '';
	for (my $i = 0; $i < length($_[0]); $i++) {
		my $ordno = ord substr($_[0], $i, 1);
		$hex .= sprintf("%lx ", $ordno);
	}

	$hex =~ s/ $//;;
	$hex;
}

sub iso2hex_new($) {
        my $hex = '';
        for (my $i = 0; $i < length($_[0]); $i++) {
                my $ordno = ord substr($_[0], $i, 1);
                my $hx = sprintf("%lx ", $ordno);
                   $hx = "0$hx" if length($hx) < 3;
                $hex .= $hx;
        }

        $hex =~ s/ $//;
        $hex;
}

sub hex2iso ($) {
	my $iso = '';
	(my $hex = $_[0]) =~ tr/ //d;
	for (my $i = 0; $i < length($hex) + 1; $i += 2) {
		my $char = pack('H8', substr($hex, $i, 2));
		$iso .= $char;
	}
	$iso;
}

sub hex2iso_new ($) {
	my $iso = '';
	(my $hex = $_[0]) =~ tr/ //d;
	for (my $i = 0; $i < length($hex); $i += 2) {
		my $char = pack('H8', substr($hex, $i, 2));
		$iso .= substr($char, 0, 1);
	}
	$iso;
}

$decimal = 153;

$binmode = unpack('B8', pack('C', $decimal));

print "Decimal $decimal = '$binmode'\n";

# <-- Decimal 153 = '10011001'

sub dec2bin($) { return sprintf("%b", $_[0]) }

sub dec2bin($) {
	my $bin = sprintf("%b", $_[0]);
	my $padding = 0;
	   $padding = 8 - length($bin) % 8 if length($bin) % 8;

	return substr('00000000', 0, $padding) . $bin;
}

sub hex2dec($) {
        eval "return sprintf(\"\%d\", 0x$_[0])";
}

sub hex2dec($) { return hex $_[0] }

my $res = &dec2addends( number => $ARGV[0] || 153 );

foreach ( @{$res->{'add_numbers'}} ) {
        print "------> $_\n";
}

sub dec2addends (%) {
	my %args = @_;
	my %hash = (); # init

	$hash{'bin'} = dec2bin($args{'number'});

	my $factor = 2 ** (length($hash{'bin'}) - 1);

	my @add_numbers = ();
	for (my $i = 0; $i < length($hash{'bin'}); $i++) {
		my $add_number = substr($hash{'bin'}, $i, 1) * $factor;
		push(@add_numbers, $add_number) if $add_number;
		$factor /= 2;
	}

	$hash{'add_numbers'} = \@add_numbers;
	\%hash;
}

bin = '1111101000'
add_numbers = 'ARRAY(0x806552c)'
------> 512
------> 256
------> 128
------> 64
------> 32
------> 8