...what if I had needed to store/retrieve some arbitrary number of bits?
Uri's suggestion of Bit::Vector is probably what you want, but more generally, take a look at the perlop man page and read up on the bitwise operators such as &, |, ^, and the shift operators <<, >>.
Here is a test case, I am wondering how some of you would address this challenge.
Store / Retrieve four (4) fields (2 bits, 6 bits, 3 bits, 5 bits) into 2 bytes
Example:
## bit string: 10 101010 110 01110
custom_pack(2,42,6,14) == \xAACE
custom_unpack(\xAACE) == (2,42,6,14)
# Retrieve four fields (2 bits, 6 bits, 3 bits, 5 bits) from 2 bytes sub custom_unpack { my $bits = shift;
my @unpacked;
push(@unpacked, ($bits & 0xC000) >> 14);
push(@unpacked, ($bits & 0x3F00) >> 8);
push(@unpacked, ($bits & 0x00E0) >> 5);
push(@unpacked, $bits & 0x001F);return @unpacked; }
my $bits = 0xAACE; ## bit string: 10 101010 110 01110
print join(',',custom_unpack($bits)),"\n";
% perl bitshift.pl 2,42,6,14
-Tom
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