ipv6calc is a small utility written in programming language C to manipulate (not
only) IPv6 addresses and is able to do other tricky things. Intentions were
convering a given IPv6 address into compressed format, convering a given IPv6
address into the same format like shown in /proc/net/if_inet6 and (because it
was not difficulty) migrating the Perl program ip6_int into. Now only one
utiltity is needed to do a lot.