CipherStream/SourceFiles/Playfair.cpp

//Ciphers/Headers/Playfair.cpp
//Matthew Ellison
// Created: 4-25-18
//Modified: 5-16-18
//This file contains the implementation of the Playfair class
//It is designed to encrypt and decrypt strings using the Playfair cipher


#include "../Headers/Playfair.hpp"
#include <string>
#include <cctype>


/**
 * @brief The current library's version number
 * 
 */
const std::string Playfair::version = "1.0.1";

///The letter that needs replaced for the cipher to work
char Playfair::REPLACED = 'J';
///The letter that replaces REPLACED
char Playfair::REPLACER = 'I';
///The letter that is added to the end to make the message of even length and placed between 2 ajoining letters that are the same
char Playfair::DOUBLED = 'X';

/**
 * @brief Construct a new Playfair object
 * 
 */
Playfair::Playfair(){
	reset();
}

/**
 * @brief Destroy the Playfair object
 * 
 */
Playfair::~Playfair(){
}

/**
 * @brief Uses keyword to set the characters in grid correctly
 * 
 */
void Playfair::createGrid(){
	unsigned int row, column;
	bool found = false;
	row = column = 0;

	//Add any new leters from the keyword to the grid
	//If you reach row 5 then the entire grid has been filled
	char current;
	for(unsigned int cnt = 0;(cnt < keyword.size()) && (row < 5);++cnt){
		current = keyword[cnt];
		//If the current letter needs to be replaced, do so
		if(current == REPLACED){
			current = REPLACER;
		}

		//Search the grid for the current letter
		found = checkGrid(current);

		//If the letter is not in the grid add it
		if(!found){
			grid[row][column] = keyword[cnt];
			++column;
			//If the column number is too high reset it and advance the row
			if(column >= 5){
				column = 0;
				++row;
			}
		}
	}

	//Until you reach the end of the grid you need to start with the first letter and try to add them to the grid
	current = 'A';
	while((row < 5) && (current <= 'Z')){
		//Start here
		//Make sure the is not the replaced letter
		if(current == REPLACED){
			++current;
		}

		//Check the grid for the current letter
		found = checkGrid(current);

		//If the letter was not found in the grid add it to the current location
		if(!found){
			grid[row][column] = current;
			++column;
			//If you have reached the end of the row move to the beginning of the next one
			if(column >= 5){
				column = 0;
				++row;
			}
		}
		++current;
	}
	//Put a check here that row == 5. If it doesn't then there is a problem
	//TODO: Make this a propper exception throw rather than this
	if(row < 5){
		throw invalidGrid("smaller", row);
	}
	else if(row > 5){
		throw invalidGrid("larger", row);
	}
}

/**
 * @brief Checks if a letter is in the grid
 * 
 * @param letter The letter you want to check for
 * @return true If the letter is found
 * @return false If the letter is not found
 */
bool Playfair::checkGrid(const char letter) const{
	//Step through every element in the grid and check for it
	for(int rowCnt = 0;rowCnt < 5;++rowCnt){
		for(int colCnt = 0;colCnt < 5;++colCnt){
			//If you find the letter in the grid return true
			if(letter == grid[rowCnt][colCnt]){
				return true;
			}
			//If you reach a \0 then there are no more symbols past that and no reason to continue checking
			else if(grid[rowCnt][colCnt] == '\0'){
				return false;
			}
		}
	}
	//If it did not trigger the true, then it must be false
	return false;
}

/**
 * @brief Searches the grid for a letter
 * 
 * @param letter The letter you wish to find
 * @param row The row that the letter is found in
 * @param col The column that the letter is found in
 */
void Playfair::searchGrid(char letter, int& row, int& col){
	//Start here
	//Check if letter needs to be replaced
	if(letter == REPLACED){
		letter = REPLACER;
	}

	//Go through every element in the grid until you find the correct letter
	for(row = 0;row < 5;++row){
		for(col = 0;col < 5;++col){
			//If it is the correct letter you just need to return (row and col are passed by reference)
			if(grid[row][col] == letter){
				return;
			}
		}
	}

	//If letter was not found you need to throw an error
	throw letterNotFound(letter);
}

/**
 * @brief Makes sure all variables are blank
 * 
 */
void Playfair::reset(){
	inputString = outputString = keyword = "";
	//Clear the grid
	for(int cnt1 = 0;cnt1 < 5;++cnt1){
		for(int cnt2 = 0;cnt2 < 5;++cnt2){
			grid[cnt1][cnt2] = '\0';
		}
	}
}

/**
 * @brief Encodes inputString using the rules of the Playfair cipher and stores it in outputString
 * 
 * @return outputString
 */
std::string Playfair::encode(){
	outputString = "";
	char letter1, letter2;
	int row1, col1, row2, col2;
	//Step through every element in the input string and encode a pair
	for(unsigned int cnt = 1;cnt < inputString.size();cnt += 2){
		//Grab two elements from the input string and search the grid for them
		letter1 = inputString[cnt - 1];
		letter2 = inputString[cnt];

		//Get the location in the grid of each letter
		try{
			searchGrid(letter1, row1, col1);
			searchGrid(letter2, row2, col2);
		}
		//Catch any error that might have occurred
		catch(letterNotFound error){
			std::string errorTemp = "There was an error int he grid\n";
			errorTemp += error.getLetter();
			errorTemp += " was not found";
			return errorTemp;
		}

		//If the letters are in the same row, shift the column right by 1
		if(row1 == row2){
			++col1;
			++col2;

			//Wrap around
			if(col1 > 4){
				col1 -= 5;
			}
			if(col2 > 4){
				col2 -= 5;
			}
		}
		//If the letters are in the same column, shift the row down by 1
		else if(col1 == col2){
			++row1;
			++row2;

			//Wrap around
			if(row1 > 4){
				row1 -= 5;
			}
			if(row2 > 4){
				row2 -= 4;
			}
		}
		//If neither of the above then treat them like oposite corners in a square and swap their column variables
		else{
			std::swap(col1, col2);
		}

		//Get the new letters
		letter1 = grid[row1][col1];
		letter2 = grid[row2][col2];
		//Add the new strings to the outputString
		outputString += letter1;
		outputString += letter2;
	}

	return outputString;
}

/**
 * @brief Uses keyword to set the grid, encodes input using the rules of the Playfair cipher, and returns the new message
 * 
 * @param keyword The keyword used to create the grid
 * @param input The message that needs encoded
 * @return The encoded message
 */
std::string Playfair::encode(std::string keyword, std::string input){
	try{
		setKeyword(keyword);
	}
	//Try to catch any error that might have occurred
	catch(invalidGrid error){
		std::string errorString = "There was an error setting up the grid.\nThe grid is too ";
		errorString += error.getType();
		errorString += " with ";
		errorString += std::to_string(error.getSize());
		errorString += " rows";
		return errorString;
	}
	setInputString(input);
	return encode();
}

/**
 * @brief Decodes inputString using the rules of the Playfair cipher and stores it in outputString
 * 
 * @return outputString
 */
std::string Playfair::decode(){
	outputString = "";
	char letter1, letter2;
	int row1, col1, row2, col2;
	//Step through every element in the input string and encode a pair
	for(unsigned int cnt = 1;cnt < inputString.size();cnt += 2){
		//Grab two elements from the input string and search the grid for them
		letter1 = inputString[cnt - 1];
		letter2 = inputString[cnt];

		//Get the location in the grid of each letter
		try{
			searchGrid(letter1, row1, col1);
			searchGrid(letter2, row2, col2);
		}
		//Catch any error that might have occurred
		catch(letterNotFound error){
			std::string errorTemp = "There was an error int he grid\n";
			errorTemp += error.getLetter();
			errorTemp += " was not found";
			return errorTemp;
		}

		//If the letters are in the same row, shift the column left by 1
		if(row1 == row2){
			--col1;
			--col2;

			//Wrap around
			if(col1 < 0){
				col1 += 5;
			}
			if(col2 < 0){
				col2 += 5;
			}
		}
		//If the letters are in the same column, shift the row up by 1
		else if(col1 == col2){
			--row1;
			--row2;

			//Wrap around
			if(row1 < 0){
				row1 += 5;
			}
			if(row2 < 0){
				row2 += 4;
			}
		}
		//If neither of the above then treat them like oposite corners in a square and swap their column variables
		else{
			std::swap(col1, col2);
		}

		//Get the new letters
		letter1 = grid[row1][col1];
		letter2 = grid[row2][col2];
		//Add the new strings to the outputString
		outputString += letter1;
		outputString += letter2;
	}

	return outputString;
}

/**
 * @brief Uses keyword to set the grid, decodes input using the rules of the Playfair cipher, and returns the new message
 * 
 * @param keyword The keyword used to create the grid
 * @param input The message that needs decoded
 * @return The decoded message
 */
std::string Playfair::decode(std::string keyword, std::string input){
	try{
		setKeyword(keyword);
	}
	//Try to catch any error that might have occurred
	catch(invalidGrid error){
		std::string errorString = "There was an error setting up the grid.\nThe grid is too ";
		errorString += error.getType();
		errorString += " with ";
		errorString += std::to_string(error.getSize());
		errorString += " rows";
		return errorString;
	}
	setInputString(input);
	return decode();
}

/**
 * @brief Removes all invalid characters and sets the keyword
 * 
 * @param key The string that is used for the keyword
 */
void Playfair::setKeyword(std::string key){
	//Make sure the keyword is blank
	keyword = "";
	//Remove all punctuation and make everything capital
	for(unsigned int cnt = 0;cnt < key.size();++cnt){
		//If it is an upper case letter, just add it to the keyword
		if(isupper(key[cnt])){
			keyword += key[cnt];
		}
		//If it is a lower case letter, make it upper case and add it to the keyword
		else if(islower(key[cnt])){
			keyword += toupper(key[cnt]);
		}
		//If it is not a letter, then just ignore it
	}
	//Create the grid from the new keyword
	createGrid();
}

/**
 * @brief Returns the current keyword
 * 
 * @return The current keyword
 */
std::string Playfair::getKeyword() const{
	return keyword;
}

/**
 * @brief Removes all invalid characters and sets inputString
 * 
 * @param input The message that needs to be encoded
 */
void Playfair::setInputString(std::string input){
	//Make sure inputString is empty
	inputString = "";
	//Remove all punctuation and make everything capital
	for(unsigned int cnt = 0;cnt < input.size();++cnt){
		char temp = input[cnt];
		if(isupper(temp)){
			//If the letter is the character than needs replaced, replace it
			if(temp == REPLACED){
				temp = REPLACER;
			}
			inputString += temp;
		}
		else if(islower(temp)){
			temp = toupper(temp);
			//If the letter is the character than needs replaced, replace it
			if(temp == REPLACED){
				temp = REPLACER;
			}
			inputString += temp;
		}
		//If it is not a letter do nothing to it
	}

	//Check if anything is doubled and needs bumped down by DOUBLED
	for(unsigned int cnt = 1;cnt < inputString.size();){
		char letter1, letter2;
		//Get two adjacent letters and compare them
		letter1 = inputString[cnt - 1];
		letter2 = inputString[cnt];
		//If they are the same insert DOUBLED between them
		if(letter1 == letter2){
			inputString.insert((inputString.begin() + cnt), DOUBLED);
		}
		//If they are not the same, do nothing

		//Advance the counter by 2
		cnt += 2;
	}

	//Check if the string length is odd and add DOUBLED to the end if it is
	if((inputString.size() % 2) == 1){
		inputString += DOUBLED;
	}
}

/**
 * @brief Returns the current inputString
 * 
 * @return The current message that needs encoded/decoded
 */
std::string Playfair::getInputString() const{
	return inputString;
}

/**
 * @brief Returns the current outputString
 * 
 * @return The encoded/decoded message
 */
std::string Playfair::getOutputString() const{
	return outputString;
}

/**
 * @brief Returns a representation of the current grid
 * 
 * @return A string representation of the grid
 */
std::string Playfair::getGrid() const{
	std::string temp;
	for(int row = 0;row < 5;++row){
		for(int col = 0;col < 5;++col){
			temp += grid[row][col];
			temp += "  ";
		}
		temp += '\n';
	}
	return temp;
}

/**
 * @brief Returns REPLACED
 * 
 * @return The letter that needs replaced for the cipher to work
 */
char Playfair::getReplaced(){
	return REPLACED;
}

/**
 * @brief Makes sure replaced is a valid character and sets REPLACED
 * 
 * @param replaced The letter to replace REPLACED
 */
void Playfair::setReplaced(const char replaced){
	//Make sure the letter is in the correct range
	if(replaced >= 'A' && replaced <= 'Z'){
		//Make sure the letter is not the same as the one that is replacing it
		if(replaced != REPLACER){
			REPLACED = replaced;
		}
	}
	else if(replaced >= 'a' && replaced <= 'z'){
		REPLACED = toupper(replaced);
	}
}

/**
 * @brief Returned REPLACER
 * 
 * @return The letter that replaces REPLACED
 */
char Playfair::getReplacer(){
	return REPLACER;
}

/**
 * @brief Makes sure replacer is a valid character and sets REPLACER
 * 
 * @param replacer The letter to replace REPLACER
 */
void Playfair::setReplacer(const char replacer){
	//Make sure the letter is in the correct range
	if(replacer >= 'A' && replacer <='Z'){
		//Make sure the letter is not the same as the one that it is replacing
		if(replacer != REPLACED){
			REPLACER = replacer;
		}
	}
	else if(replacer >= 'a' && replacer <= 'z'){
		REPLACER = toupper(replacer);
	}
}

/**
 * @brief Return DOUBLED
 * 
 * @return The letter that is added to the end to make the message of even length and placed between 2 ajoining letters that are the same 
 */
char Playfair::getDoubled(){
	return DOUBLED;
}

/**
 * @brief Makes sure doubled is a valid character and sets DOUBLED
 * 
 * @param doubled The letter to replace DOUBLED
 */
void Playfair::setDoubled(const char doubled){
	//Make sure the letter is in the correct range
	if(doubled >= 'A' && doubled <= 'Z'){
		DOUBLED = doubled;
	}
	else if(doubled >= 'a' && doubled <= 'z'){
		DOUBLED = toupper(doubled);
	}
}

/**
 * @brief Returns a string containing the version information
 * 
 * @return The version information
 */
std::string Playfair::getVersion(){
	return version;
}