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Implement indexOf methods for alphabet and series

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These methods are implemented on the classes that own those sequences. Less confusion is good. :)
This commit is contained in:
Eryn Wells 2015-07-19 08:20:16 -07:00
parent 9345b4e3f9
commit ef45cb9718
1 changed files with 25 additions and 27 deletions
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52
Enigma/Components.swift
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@ -10,8 +10,10 @@ import Foundation
enum EncoderError: ErrorType {
/** Thrown when an input character is found that is not in the alphabet. */
case InvalidCharacter(ch: Character)
/** Input character is not in the alphabet. */
case CharacterNotInAlphabet(ch: Character)
/** Input character is not found in a rotor's series. */
case CharacterNotInSeries(ch: Character)
}
@ -24,6 +26,14 @@ protocol Encoder {
class Cryptor {
/** Array of all possible characters to encrypt. */
static let alphabet: [Character] = Array("ABCDEFGHIJKLMNOPQRSTUVWXYZ".characters)
func indexOfInAlphabet(c: Character) throws -> Int {
if let index = Cryptor.alphabet.indexOf(c) {
return index
} else {
throw EncoderError.CharacterNotInAlphabet(ch: c)
}
}
}
@ -49,18 +59,18 @@ class FixedRotor: Cryptor, Encoder {
}
func encode(c: Character) throws -> Character {
if let offset = FixedRotor.alphabet.indexOf(c) {
return series[offset]
} else {
throw EncoderError.InvalidCharacter(ch: c)
}
return series[try indexOfInAlphabet(c)]
}
func inverseEncode(c: Character) throws -> Character {
if let offset = series.indexOf(c) {
return FixedRotor.alphabet[offset]
return Cryptor.alphabet[try indexOfInSeries(c)]
}
func indexOfInSeries(c: Character) throws -> Int {
if let index = series.indexOf(c) {
return index
} else {
throw EncoderError.InvalidCharacter(ch: c)
throw EncoderError.CharacterNotInSeries(ch: c)
}
}
}
@ -123,19 +133,11 @@ class Rotor: FixedRotor {
}
override func encode(c: Character) throws -> Character {
if let offset = Rotor.alphabet.indexOf(c) {
return series[(offset + ringPosition + position) % series.count]
} else {
throw EncoderError.InvalidCharacter(ch: c)
}
return series[(try indexOfInAlphabet(c) + ringPosition + position) % series.count]
}
override func inverseEncode(c: Character) throws -> Character {
if let offset = series.indexOf(c) {
return Rotor.alphabet[(offset + ringPosition + position) % Rotor.alphabet.count]
} else {
throw EncoderError.InvalidCharacter(ch: c)
}
return Cryptor.alphabet[(try indexOfInSeries(c) + ringPosition + position) % Rotor.alphabet.count]
}
}
@ -164,12 +166,8 @@ class Reflector: FixedRotor {
func validateReflector(series: [Character]) throws {
for (offset, c) in series.enumerate() {
if let alphabetOffset = Reflector.alphabet.indexOf(c) {
if series[alphabetOffset] != Reflector.alphabet[offset] {
throw Error.InvalidReflection
}
} else {
throw EncoderError.InvalidCharacter(ch: c)
if series[try indexOfInAlphabet(c)] != Cryptor.alphabet[offset] {
throw Error.InvalidReflection
}
}
}
@ -191,7 +189,7 @@ class Plugboard: Cryptor, Encoder {
} else if Plugboard.alphabet.contains(c) {
return c
} else {
throw EncoderError.InvalidCharacter(ch: c)
throw EncoderError.CharacterNotInAlphabet(ch: c)
}
}