I want to take an IP address routing prefix in CIDR [1] notation (i.e. the 24 in "192.168.100.14/24") and convert it into subnet form (i.e. 255.255.255.0). I came up with 4 ways to do that (see below), but none stand out as best (although #3 and #4 seem a bit more straightforward as they avoid the `max` temp).
How would you go about it? Here are the ways I came up with: cidr := 24. shift := 32 - cidr. max := #[ 255 255 255 255 ] asInteger. "1." ((max bitShift: shift negated) bitShift: shift) asByteArray. "2." (max bitClear: (2 raisedTo: shift) - 1) asByteArray. "3." ((2 raisedTo: shift) - 1) bitInvert32 asByteArray. "4." (((2 raisedTo: cidr) - 1) bitShift: shift) asByteArray 1. https://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing ----- Cheers, Sean -- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html
