enigma.cpp

//
//  main.cpp
//  enigma
//
//  Created by Henrique de Almeida on 27/10/2018.
//  Copyright © 2018 Henrique de Almeida. All rights reserved.
//

#include <iostream>

#include <fstream>
#include <string>
#include <vector>

#include <algorithm>

unsigned int rotorIPos      = 0;
unsigned int rotorIIPos     = 0;
unsigned int rotorIIIPos    = 0;

const unsigned int GOING = 1;
const unsigned int COMING = 2;
const unsigned int READING = 3;
const unsigned int WRITING = 4;
const unsigned int ALPHABET_LENGTH = 26;

char pins[] =             {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'X', 'W', 'Y', 'Z'};

char rotorIPlates[] =     {'T', 'Y', 'K', 'Q', 'W', 'E', 'P', 'V', 'X', 'U', 'R', 'Z', 'N', 'H', 'F', 'M', 'J', 'S', 'D', 'O', 'C', 'G', 'L', 'A', 'I', 'B'};

char rotorIIPlates[] =    {'P', 'Z', 'I', 'K', 'L', 'E', 'G', 'F', 'J', 'Q', 'S', 'T', 'V', 'A', 'N', 'D', 'B', 'X', 'W', 'M', 'R', 'Y', 'H', 'C', 'U', 'O'};

char rotorIIIPlates[] =   {'V', 'K', 'R', 'D', 'X', 'H', 'L', 'M', 'U', 'J', 'Q', 'N', 'E', 'B', 'Z', 'Y', 'G', 'C', 'S', 'O', 'A', 'W', 'T', 'P', 'I', 'F'};

//char reflector[] =        {'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'X', 'W', 'Y', 'Z', 'A', 'B', 'C', 'D', 'E'};

static char rotor(unsigned int flow, char *plates, unsigned int pos, char input);
static void refreshPositions(unsigned int flow);
static char encript(char input);
static char decript(char input);
static char reflect(char input, char *plates);

int main(int argc, const char * argv[]) {
    
    std::string plain = "OIISABELA";
    std::string encripted;
    for (int i = 0; i < plain.size(); i++) {
        char temp = encript(plain[i]);
        encripted.append(&temp);
        
        //std::cout << rotorIIIPos << " " << rotorIIPos << " " << rotorIPos << std::endl;
    }
    
    std::cout << std::endl << "  Writing" << std::endl;
    std::cout << "" << std::endl;
    std::cout << "Mensagem original:    " << plain << std::endl;
    std::cout << "Mensagem encriptada:  ";
    
    for (int i = 0; i < encripted.length(); i++) {
        
        if (encripted[i] >= 'A' && encripted[i] <= 'Z') {
            std::cout << encripted[i];
        }
    }
    
    std::cout << "" << std::endl << std::endl;
    
    //----------------------------------------------------------------------------------------------------
    
    rotorIPos =     0;
    rotorIIPos =    0;
    rotorIIIPos =   0;
    
    std::string encripted2 = "MUEHLEICO";
    std::string plain2;
    for (int i = 0; i < encripted2.size(); i++) {
        char temp = decript(encripted2[i]);
        plain2.append(&temp);
        
        //std::cout << rotorIIIPos << " " << rotorIIPos << " " << rotorIPos << std::endl;
    }
    std::cout << "  Reading" << std::endl;
    std::cout << "" << std::endl;
    std::cout << "Mensagem encriptada:  " << encripted2 << std::endl;
    std::cout << "Mensagem original:    " << plain << std::endl << std::endl;
    
    return 0;
}

static char rotor(unsigned int flow, char *plates, unsigned int pos, char input){
    
    unsigned int index;
    if (flow == GOING) {
        for (unsigned int i = 0; i < ALPHABET_LENGTH; i++){
            index = (i + pos) % 26;
            if (input == pins[i]) {
                return plates[index];
            }
        }
    } else if (flow == COMING){
        for (unsigned int i = 0; i < ALPHABET_LENGTH; i++){
            index = (i + pos) % 26;
            if (input == plates[i]) {
                return pins[index];
            }
        }
    }
    
    return NULL;
}

static char rotor2(unsigned int flow, char *plates, unsigned int pos, char input){
    
    unsigned int index;
    if (flow == GOING) {
        for (unsigned int i = 0; i < ALPHABET_LENGTH; i++){
            index = (i - pos + 26) % 26;
            if (input == pins[i]) {
                return plates[index];
            }
        }
    } else if (flow == COMING){
        for (unsigned int i = 0; i < ALPHABET_LENGTH; i++){
            index = (i - pos + 26) % 26;
            if (input == plates[i]) {
                return pins[index];
            }
        }
    }
    
    return NULL;
}


static char reflect(int mode, char input, char *plates){
    
    if (mode == WRITING) {
        for (int i = 0; i < ALPHABET_LENGTH; i++) {
            if (plates[i] == input) {
                return rotorIIIPlates[(i - 4 + 26)%26];
            }
        }
    }
    if (mode == READING){
        for (int i = 0; i < ALPHABET_LENGTH; i++) {
            if (plates[i] == input) {
                return rotorIIIPlates[(i + 4)%26];
            }
        }
    }
    return NULL;
}

static void refreshPositions(unsigned int flow){
    
    if (flow == WRITING) {
        if (rotorIPos == ALPHABET_LENGTH - 1) {
            rotorIPos = 0;
            
            if (rotorIIPos == ALPHABET_LENGTH - 1) {
                rotorIIPos = 0;
                
                if (rotorIIIPos == ALPHABET_LENGTH - 1) {
                    rotorIIIPos = 0;
                } else {
                    rotorIIIPos++;
                }
            } else {
                rotorIIPos++;
            }
        } else {
            rotorIPos++;
        }
    } else if (flow == READING) {
        if (rotorIPos == 0) {
            rotorIPos = ALPHABET_LENGTH - 1;
            
            if (rotorIIPos == 0) {
                rotorIIPos = ALPHABET_LENGTH - 1;
                
                if (rotorIIIPos == 0) {
                    rotorIIIPos = ALPHABET_LENGTH - 1;
                } else {
                    rotorIIIPos--;
                }
            } else {
                rotorIIPos--;
            }
        } else {
            rotorIPos--;
        }
    }
}

static char encript(char input){
    
    char currentCharacter = input;
    
    currentCharacter = rotor(GOING, rotorIPlates, rotorIPos, currentCharacter);//std::cout << currentCharacter << std::endl;
    currentCharacter = rotor(GOING, rotorIIPlates, rotorIIPos, currentCharacter);//std::cout << currentCharacter << std::endl;
    currentCharacter = rotor(GOING, rotorIIIPlates, rotorIIIPos, currentCharacter);//std::cout << currentCharacter << std::endl;
    
    currentCharacter = reflect(WRITING, currentCharacter, rotorIIIPlates);//std::cout << currentCharacter << std::endl;
    
    currentCharacter = rotor(COMING, rotorIIIPlates, rotorIIIPos, currentCharacter);//std::cout << currentCharacter << std::endl;
    currentCharacter = rotor(COMING, rotorIIPlates, rotorIIPos, currentCharacter);//std::cout << currentCharacter << std::endl;
    currentCharacter = rotor(COMING, rotorIPlates, rotorIPos, currentCharacter);//std::cout << currentCharacter << std::endl;
    refreshPositions(WRITING);
    
    return currentCharacter;
}

static char decript(char input){
    
    char currentCharacter = input;
    
    currentCharacter = rotor2(GOING, rotorIPlates, rotorIPos, currentCharacter);//std::cout << currentCharacter << std::endl;
    currentCharacter = rotor2(GOING, rotorIIPlates, rotorIIPos, currentCharacter);//std::cout << currentCharacter << std::endl;
    currentCharacter = rotor2(GOING, rotorIIIPlates, rotorIIIPos, currentCharacter);//std::cout << currentCharacter << std::endl;
    
    currentCharacter = reflect(READING, currentCharacter, rotorIIIPlates);
    
    currentCharacter = rotor2(COMING, rotorIIIPlates, rotorIIIPos, currentCharacter);//std::cout << currentCharacter << std::endl;
    currentCharacter = rotor2(COMING, rotorIIPlates, rotorIIPos, currentCharacter);//std::cout << currentCharacter << std::endl;
    currentCharacter = rotor2(COMING, rotorIPlates, rotorIPos, currentCharacter);//std::cout << currentCharacter << std::endl;
    refreshPositions(WRITING);
    
    return currentCharacter;
}