Re: Reading Binary

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];
[download]

As Occam said: Entia non sunt multiplicanda praeter necessitatem.

Comment on Re: Reading Binary Download Code

Replies are listed 'Best First'.
Re^2: Reading Binary by jwkrahn (Abbot) on Jun 15, 2011 at 20:47 UTC
`$bin =~ m{([01]+)}; # untaint input my $idx = eval "0b$1";` [download] You shouldn't use the results of a regular expression unless you verify that it matched correctly. Why use string eval when oct is less dangerous and provides the same result.	[reply] [d/l]