Sha256: 019f3d36a4e87dc0029f94ea5e02660e8c5ab5d80b4daa562402033f0a902899
Contents?: true
Size: 953 Bytes
Versions: 84
Compression:
Stored size: 953 Bytes
Contents
-module(atbash_cipher).
-export([encode/1, decode/1]).
encode(String) ->
join(chunk(convert(String), 5)).
decode(String) ->
convert(String).
%% Basic conversion routines
convert(String) ->
lists:filtermap(fun encode_char/1, String).
encode_char(C) when C >= $A, C =< $Z ->
%% shift to lower-case
{true, $Z - C + $a};
encode_char(C) when C >= $a, C =< $z ->
{true, $z - C + $a};
encode_char(C) when C >= $0, C =< $9 ->
{true, C};
encode_char(_C) ->
false.
%%
%% Functions for converting to word chunks of 5 characters
join(Lists) ->
string:join(Lists, " ").
chunk(String, N) ->
lists:reverse(chunk(
lists:split(min(length(String), N),
String), [], N)).
chunk({Last, []}, Accum, _N) ->
[Last] ++ Accum;
chunk({Next, Remainder}, Accum, N) ->
chunk(
lists:split(min(length(Remainder), N),
Remainder), [Next] ++ Accum, N).
%%
Version data entries
84 entries across 84 versions & 1 rubygems