Re: Reading Binary

[TomDLux]

Given some input string representing a binary number, $bin, verify it only contains 1 & 0, to protect little Bobby Tables, then convert to an ordinary number. You only have 15 values to deal with, so you can hardcode an array. If it's 10 to 20 bits, you can precompute the array; if it's more, probably better to stick with calculating things as you need them, possibly with memoizing.

my @block = qw( D C CD B BD BC BCD A AD AC ACD AB ABD ABC ABCD );
unshift @block, '';   # empty string for 0

$bin =~ m{([01]+)};     # untaint input
my $idx = eval "0b$1";

my $result = $block[$idx];

[jwkrahn]

$bin =~ m{([01]+)};     # untaint input
my $idx = eval "0b$1";

1. You shouldn't use the results of a regular expression unless you verify that it matched correctly.
2. Why use string eval when oct is less dangerous and provides the same result.