Affine.java created online with Bitbucket

src/main/java/com/mattrixwv/CipherStreamJava/monoSubstitution/Affine.java

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+//CipherStreamJava/src/main/java/com/mattrixwv/CipherStreamJava/polySubstitution/Affine.java
+//Mattrixwv
+// Created: 01-26-22
+//Modified: 01-26-22
+package com.mattrixwv.CipherStreamJava.monoSubstitution;
+
+
+import com.mattrixwv.CipherStreamJava.exceptions.InvalidInputException;
+import com.mattrixwv.CipherStreamJava.exceptions.InvalidKeywordException;
+
+
+public class Affine{
+	private boolean preserveCapitals;
+	private boolean preserveSymbols;
+	private boolean preserveWhitespace;
+	private String inputString;
+	private String outputString;
+	private int key1;	//Key1 must be relatively prime to 26
+	private int key2;
+
+	private void setKey1(int key1) throws InvalidKeywordException{
+		//If the key is negative change it to possitive
+		if(key1 < 0){
+			key1 %= 26;
+			key1 += 26;
+		}
+
+		//Make sure the key is relatively prime to 26 (The number of letters)
+		if(gcd(key1, 26) != 1){
+			throw new InvalidKeywordException("Key 1 must be relatively prime to 26");
+		}
+
+		//Save the key
+		this.key1 = key1;
+	}
+	private void setKey2(int key2){
+		//If the key is negative change it to possitive
+		if(key2 < 0){
+			key2 %= 26;
+			key2 += 26;
+		}
+
+		//Save the key
+		this.key2 = key2;
+	}
+	private void setInputString(String inputString) throws InvalidInputException{
+		if(inputString == null){
+			throw new InvalidInputException("Input must not be null");
+		}
+
+		if(!preserveCapitals){
+			inputString = inputString.toLowerCase();
+		}
+		if(!preserveWhitespace){
+			inputString = inputString.replaceAll("\\s+", "");
+		}
+		if(!preserveSymbols){
+			inputString = inputString.replaceAll("[^a-zA-Z\\s]", "");
+		}
+
+		this.inputString = inputString;
+
+		if(this.inputString.isBlank()){
+			throw new InvalidInputException("Input cannot be blank");
+		}
+	}
+	private String encode(){
+		//Step through every character in the input and encode it if needed
+		StringBuilder output = new StringBuilder();
+		for(char ch : inputString.toCharArray()){
+			//Encode all letters
+			if(Character.isUpperCase(ch)){
+				//Change the character to a number
+				int letter = ch - 65;
+				//Encode the number
+				letter = ((key1 * letter) + key2) % 26;
+				//Change the new number back to a character and append it to the output
+				char newChar = (char)(letter + 65);
+				output.append(newChar);
+			}
+			else if(Character.isLowerCase(ch)){
+				//Change the character to a number
+				int letter = ch - 97;
+				//Encode the number
+				letter = ((key1 * letter) + key2) % 26;
+				//Change the new number back to a character and append it to the output
+				char newChar = (char)(letter + 97);
+				output.append(newChar);
+			}
+			//Pass all other characters through
+			else{
+				output.append(ch);
+			}
+		}
+
+		//Save and return the output
+		outputString = output.toString();
+		return outputString;
+	}
+	private String decode(){
+		//Find the multiplicative inverse of key1
+		int key1I = 1;
+		while(((key1 * key1I) % 26) != 1){
+			++key1I;
+		}
+
+		//Step through every character in the input and decode it if needed
+		StringBuilder output = new StringBuilder();
+		for(char ch : inputString.toCharArray()){
+			//Encode all letters
+			if(Character.isUpperCase(ch)){
+				//Change the letter to a number
+				int letter = ch - 65;
+				//Encode the number
+				letter = (key1I * (letter - key2)) % 26;
+				if(letter < 0){
+					letter += 26;
+				}
+				//Change the new number back to a character and append it to the output
+				char newChar = (char)(letter + 65);
+				output.append(newChar);
+			}
+			else if(Character.isLowerCase(ch)){
+				//Change the letter to a number
+				int letter = ch - 97;
+				//Encode the number
+				letter = (key1I * (letter - key2)) % 26;
+				if(letter < 0){
+					letter += 26;
+				}
+				//Change the new number back to a character and append it to the output
+				char newChar = (char)(letter + 97);
+				output.append(newChar);
+			}
+			//Pass all other characters through
+			else{
+				output.append(ch);
+			}
+		}
+
+		//Save and return the output
+		outputString = output.toString();
+		return outputString;
+	}
+
+	public Affine(){
+		preserveCapitals = false;
+		preserveSymbols = false;
+		preserveWhitespace = false;
+		reset();
+	}
+	public Affine(boolean preserveCapitals, boolean preserveWhitespace, boolean preserveSymbols){
+		this.preserveCapitals = preserveCapitals;
+		this.preserveSymbols = preserveSymbols;
+		this.preserveWhitespace = preserveWhitespace;
+		reset();
+	}
+	public String encode(int key1, int key2, String inputString) throws InvalidKeywordException, InvalidInputException{
+		setKey1(key1);
+		setKey2(key2);
+		setInputString(inputString);
+		return encode();
+	}
+	public String decode(int key1, int key2, String inputString) throws InvalidKeywordException, InvalidInputException{
+		setKey1(key1);
+		setKey2(key2);
+		setInputString(inputString);
+		return decode();
+	}
+
+	public void reset(){
+		inputString = "";
+		outputString = "";
+		key1 = 0;
+		key2 = 0;
+	}
+	public String getInputString(){
+		return inputString;
+	}
+	public String getOutputString(){
+		return outputString;
+	}
+	public int getKey1(){
+		return key1;
+	}
+	public int getKey2(){
+		return key2;
+	}
+	//TODO: Change to my library's version
+	//This function returns the GCD of the two numbers sent to it
+	public static int gcd(int num1, int num2){
+		while((num1 != 0) && (num2 != 0)){
+			if(num1 > num2){
+				num1 %= num2;
+			}
+			else{
+				num2 %= num1;
+			}
+		}
+		return num1 | num2;
+	}
+}