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Contents
# frozen_string_literal: true
class String
# "Encrypt / Decrypt" the string with Caesar cipher. This will shift the
# alphabet letters by +n+, where +n+ is the integer key. The same function
# is used for encryption / decryption.
# @param opts [Hash] optional parameters
# @option opts [Integer] :shift The shift key. Default value: 13.
# @see https://en.wikipedia.org/wiki/Caesar_cipher
# @return [String] the (de)ciphered string
# @example
# 'Hello world!'.rot # => "Uryyb jbeyq!"
# 'Hello world!'.rot(shift: 11) # => "Spwwz hzcwo!"
# 'Uryyb jbeyq!'.rot # => "Hello world!"
# 'Spwwz hzcwo!'.rot(shift: 26-11) # => "Hello world!"
def rot(opts = {})
opts[:shift] ||= 13
alphabet = Array('a'..'z')
lowercase = Hash[alphabet.zip(alphabet.rotate(opts[:shift]))]
alphabet = Array('A'..'Z')
uppercasecase = Hash[alphabet.zip(alphabet.rotate(opts[:shift]))]
encrypter = lowercase.merge(uppercasecase)
chars.map { |c| encrypter.fetch(c, c) }.join
end
# "Encrypt / Decrypt" the string with Caesar cipher in place as described for
# {String#rot}.
# @return [String] the (de)ciphered string as well as changing changing the
# object in place.
# @example
# a = 'Bonjour le monde !' # => "Bonjour le monde !"
# a.rot! # => "Obawbhe yr zbaqr !"
# a # => "Obawbhe yr zbaqr !"
def rot!(opts = {})
replace(rot(opts))
end
# Alias for {String#rot} with default value ( +rot(shift: 13)+ ).
def rot13
rot
end
# Alias for {String#rot!} with default value ( +rot!(shift: 13)+ ).
def rot13!
rot!
end
end
Version data entries
10 entries across 10 versions & 1 rubygems