public class HashHelper {

    // Hash Function 0: Convertion of chars according to their position in word + some constant value
    public static String hash(String input) {
        String hashed = "";
        int salt = 8;
        for (int i = 0; i < input.length(); i++) {
            char ch = (char) (input.charAt(i) + i + salt);
            hashed += ch;
        }
        return hashed;
    }
    // Hash Function 1: Sum of character values (in this scenario hash will not always have the same length as
    // an input string)
    public static String hashSum(String input) {
        int hash = 0;
        for (char c : input.toCharArray()) {
            hash += c;
        }
        return Integer.toHexString(hash);
    }

    // Hash Function 2: XOR of character values - in java ^ is a XOR (exclusive or) operator
    // it is only true when two compared bits are different e.g. 1 XOR 0 = 1 but 1 XOR 1 = 0
    public static String hashXOR(String input) {
        int hash = 0;
        for (char c : input.toCharArray()) {
            hash ^= c;
        }
        return Integer.toHexString(hash);
    }

    // Hash Function 3: Bit shift with addition
    public static String hashShift(String input) {
        int hash = 0;
        for (char c : input.toCharArray()) {
            hash = (hash << 5) - hash + c;
        }
        return Integer.toHexString(hash);
    }

    // Hash Function 4: Multiplication by a constant
    public static String hashMultiply(String input) {
        int hash = 1;
        for (char c : input.toCharArray()) {
            hash = hash * 31 + c;
        }
        return Integer.toHexString(hash);
    }

    // Hash Function 5: Simple cyclic sum  (modulo division, where % is a modulo operator)
    public static String hashCyclicSum(String input) {
        int hash = 0;
        for (char c : input.toCharArray()) {
            hash = (hash + c) % 256;
        }
        return Integer.toHexString(hash);
    }

}