Re^7: Incrementing a large number without Math::BigInt

Yes, I actually noticed this node while searching for a solution to my problem. But isn't that more of an ASCII feature than a Perl one? I wonder why the deincrementing and bit shifting don't work.

Comment on Re^7: Incrementing a large number without Math::BigInt

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Re^8: Incrementing a large number without Math::BigInt by ikegami (Patriarch) on Apr 26, 2006 at 06:33 UTC
ASCII has nothing to do with it. You can use those operators on any string of bytes, whether the data is ASCII, the result of `inet_aton` or a struct to pass to a system call. The operators work independantly of how the data is interpreted. Now, `$letter ^ ' '` will not toggle the case of the letter in all encodings, but that's a (simple) algorithm that uses `^` and not `^` proper. Here's an example which demonstrates that `^` work no matter how the data was encoded: `use Socket qw( inet_aton inet_ntoa ); my $ip = inet_aton('10.0.0.155'); my $mask = inet_aton('255.255.255.240'); my $broadcast = $ip \| ~$mask; print(inet_ntoa($broadcast), "\n"); # 10.0.0.159` [download] It's definitely a language feature, and I believe an uncommon one. You can't do that in C or Java, for example.	[reply] [d/l] [select]

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Re^8: Incrementing a large number without Math::BigInt
by ikegami (Patriarch) on Apr 26, 2006 at 06:33 UTC

ASCII has nothing to do with it. You can use those operators on any string of bytes, whether the data is ASCII, the result of inet_aton or a struct to pass to a system call. The operators work independantly of how the data is interpreted.

Now, $letter ^ ' ' will not toggle the case of the letter in all encodings, but that's a (simple) algorithm that uses ^ and not ^ proper.

Here's an example which demonstrates that ^ work no matter how the data was encoded:

use Socket qw( inet_aton inet_ntoa );

my $ip        = inet_aton('10.0.0.155');
my $mask      = inet_aton('255.255.255.240');
my $broadcast = $ip | ~$mask;

print(inet_ntoa($broadcast), "\n");  # 10.0.0.159
[download]

It's definitely a language feature, and I believe an uncommon one. You can't do that in C or Java, for example.

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