* * @param {String} prev * @param {String} next * @returns {Array} of [String, Boolean]

* @returns {String} * @param {Number} byte

* @returns {Number} * @param {string} char

* @param {Number} i * @param {String} str * @param {Number} defaultChar

* * @param {Number} prev * @param {Number} next * @returns {Number}