caesar-salad/substitution-cipher.js

Caesar, Vigenere and ROT Ciphers.

/* eslint-disable no-unused-vars,valid-jsdoc */
'use strict';

const CharBuffer = require('char-buffer');

/**
 * Abstract base class for substitution ciphers (and substitution deciphers).
 *
 * Substitution ciphers replace letters of plaintext by other letters. See <a class="external" href="https://en.wikipedia.org/wiki/Substitution_cipher">Wikipedia</a> for details.
 *
 * @class SubstitutionCipher
 */
class SubstitutionCipher {
	/**
	 * Abstract method to substitute a single charCode.
	 *
	 * @method _substituteCharCode
	 * @param {Number} input The charCode to process.
	 * @return {Number} The processed charCode.
	 */
	_substituteCharCode(input) {
		throw new Error('_substituteCharCode not implemented');
	}

	/**
	 * Template method to encrypt/decrypt strings substituting its input charCode by charCode.
	 *
	 * @method crypt
	 * @param {String} input The string to process.
	 * @return {Number} The processed string.
	 */
	crypt(input) {
		return CharBuffer.fromString(input,
			this._substituteCharCode, this).toString();
	}
}

/**
 * Abstract method to create a cipher instance.
 *
 * @method Cipher
 * @static
 * @return {SubstitutionCipher} The Cipher.
 */
SubstitutionCipher.Cipher = function () {
	throw new Error('Cipher not implemented');
};

/**
 * Abstract method to create a decipher instance.
 *
 * @method Decipher
 * @static
 * @return {SubstitutionCipher} The Decipher.
 */
SubstitutionCipher.Decipher = function () {
	throw new Error('Decipher not implemented');
};

module.exports = SubstitutionCipher;