Question

I’m quite new to Perl development, and I’d like to perform a following task:

My script receives hex-encoded string as command-line param. Then I must decode this string and write it to output file like a C++ array with initialization from data given. For example:

perl myscript.pl DEADBABEDEADBEEF
and the output something like

const boost::array<char, 8> MyArray = { 0xDE, 0xAD, 0xBA, 0xBE, 0xDE, 0xAD, 0xBE, 0xEF };

What is the right way to do this with Perl regex? Of course, I could perform it in loop with substrings, but I believe that there should be more elegant way.

EDIT: the input string is of fixed length.

Answer 1

Try this:

my $hex = "DEADBABEDEADBEEF";
my @a = map "0x$_", $hex =~ /(..)/g;

How it works:

First, $hex =~ /(..)/g in list context captures all 2-character substrings (the /g flag means global match). Then map() takes the list and transforms it to another one, using the "0x$_" expression for each element of the first list ($_ here is an alias for the element).

See also perldoc -f map.