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package de.romjaki.selfbot;
import java.util.ArrayList;
/**
* COMP 249 - Assignment 4 Q1
* Due Friday, April 11, 2014
*
* Rot-N algorithm, Encryption / Decryption
* @version 1.0
* */
public class Rot {
private ArrayList<String> letters;
private ArrayList<String> encryptedLetters;
public Rot(){
letters = new ArrayList<String>();
encryptedLetters = new ArrayList<String>();
}
/**
* Encrypt text
* @param message Message to encrypt
* @param rotN Rot number
* @param encryptDigit True or False
* @return encrypted message
* */
public String encrypt(String message, int rotN, boolean encryptDigit){
String out = "";
char encryptedCurrent;
char current;
int typeAlpha;
//clear arrays
letters.clear();
encryptedLetters.clear();
for(int i=0; i<message.length();i++){
current = message.charAt(i);
if((typeAlpha = typeAlpha(current)) != 0){
encryptedCurrent = (char) (current + rotN);
if(typeAlpha == 1 && encryptedCurrent > 'z' || typeAlpha == 2 && encryptedCurrent > 'Z')
encryptedCurrent -= 'z' - 'a' + 1;
}else if(encryptDigit && isNumeric(current)){
encryptedCurrent = (char) (current + rotN%10);
if(encryptedCurrent > '9')
encryptedCurrent -= '9' - '0' + 1;
} else {
encryptedCurrent = current;
}
if((typeAlpha != 0 || (isNumeric(current) && encryptDigit)) && letters.indexOf(current+"") == -1){
letters.add(current+"");
encryptedLetters.add(encryptedCurrent+"");
}
out += encryptedCurrent;
}
return out;
}
/**
* Decrypt text
* @param message Message to decrypt
* @param rotN Rot number
* @param decryptDigit True or False
* @return decrypted message
* */
public String decrypt(String message, int rotN, boolean decryptDigit){
String out = "";
char encryptedCurrent;
char current;
int typeAlpha;
//clear arrays
letters.clear();
encryptedLetters.clear();
for(int i=0; i<message.length();i++){
current = message.charAt(i);
if((typeAlpha = typeAlpha(current)) != 0){
encryptedCurrent = (char) (current - rotN);
if(typeAlpha == 1 && encryptedCurrent < 'a' || typeAlpha == 2 && encryptedCurrent < 'A')
encryptedCurrent += 'z' - 'a' + 1;
}else if(decryptDigit && isNumeric(current)){
encryptedCurrent = (char) (current - rotN%10);
if(encryptedCurrent < '0')
encryptedCurrent += '9' - '0' + 1;
} else {
encryptedCurrent = current;
}
if((typeAlpha != 0 || (isNumeric(current) && decryptDigit)) && letters.indexOf(current+"") == -1){
letters.add(current+"");
encryptedLetters.add(encryptedCurrent+"");
}
out += encryptedCurrent;
}
return out;
}
/**
* Check if the character is alphabetic
* @param c Character
* @return 1 => Lowercase, 2 => Uppercase, 3 => Not alpha
* */
public int typeAlpha(char c) {
if(c >= 'a' && c <= 'z')
return 1;
if(c >= 'A' && c <= 'Z')
return 2;
return 0;
}
/**
* Check if character is a number
* @param c Character
* @return true or false
* */
public boolean isNumeric(char c) {
return c >= '0' && c <= '9';
}
/**
* Get original letters
* @return original letters
* */
public ArrayList<String> getLetters(){
return letters;
}
/**
* Get encrypted letters
* @return encrypted/decrypted letters
* */
public ArrayList<String> getEncryptedLetters(){
return encryptedLetters;
}
}
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