Re^3: Bitwise AND with large numbers

in reply to Re^2: Bitwise AND with large numbers
in thread Bitwise AND with large numbers

This works fine for me:

use Math::BigInt;

my $switchPortNumber = 2;
# 32 Character hex string from switch
my $hexstring = Math::BigInt->new('0x40000000000000000000000000000000'
+); 
my $mask = (Math::BigInt->new('0x80000000000000000000000000000000') >>
+ $switchPortNumber);
my $result = ($hexstring & $mask) > 0;
[download]

Another approach would be to turn it into an ASCII bitstring, in which case you can use a simple substr() instead of the AND masking

my $bitstring = unpack('B*', pack('H*', '40000000000000000000000000000
+000'));
my $result = substr($bitstring, $switchPortNumber, 1) eq '1';
[download]

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Re^4: Bitwise AND with large numbers by mdej (Initiate) on Apr 20, 2012 at 08:20 UTC
Hey Eliya, Thanks for the quick response. Your solutions look promising. I especially like the one where you turn the hex string in a ASCII bit string. I will try this with my code and test it with the switch. I will let you know how things went.	[reply]

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