Canonicalize CIDR: Difference between revisions
→OCaml: add
(→{{header|TXR}}: Remove the solution which wastefully does the bit stripping that naddr-str already performed.) |
(→OCaml: add) |
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Line 1,215:
161.214.74.21/24 ⇢ 161.214.74.0/24
184.232.176.184/18 ⇢ 184.232.128.0/18</pre>
=={{header|OCaml}}==
<syntaxhighlight lang="ocaml">let mask = function
| _, 0 -> 0l, 0
| a, l -> Int32.(logand (shift_left minus_one (-l land 31)) a), l
let str_to_cidr s =
let (<<+) b a = Int32.(add (shift_left b 8) a) in
let recv d c b a l = d <<+ c <<+ b <<+ a, l in
Scanf.sscanf s "%3lu.%3lu.%3lu.%3lu/%2u" recv
let cidr_to_str (a, l) =
let addr n =
let dgt = function
| h :: t -> Int32.shift_right_logical h 8 :: Int32.logand h 255l :: t
| l -> l
in
dgt [n] |> dgt |> dgt |> List.map Int32.to_string |> String.concat "."
in
Printf.sprintf "%s/%u" (addr a) l
let () =
["87.70.141.1/22"; "36.18.154.103/12"; "62.62.197.11/29"; "67.137.119.181/4"; "161.214.74.21/24"; "184.232.176.184/18"; "10.207.219.251/32"]
|> List.iter (fun s -> str_to_cidr s |> mask |> cidr_to_str |> print_endline)</syntaxhighlight>
{{out}}
<pre>
87.70.140.0/22
36.16.0.0/12
62.62.197.8/29
64.0.0.0/4
161.214.74.0/24
184.232.128.0/18
10.207.219.251/32
</pre>
=={{header|Perl}}==
There's a CPAN module for IP address manipulation, <tt>Net::IP</tt>. Unfortunately, it requires a CIDR string to be already in canonical form; otherwise it fails with an "Invalid prefix" error. So we do it manually.
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