/**
 * encode a string to base64
 *
 * @param {string} str string to encode
 * @param {string} encoding encoding the string is in
 * @returns {string} base64
 */
export function to_b64(str: string, encoding?: string): string;
/**
 * encode a string to hex
 *
 * @param {string} str string to encode
 * @param {string} encoding encoding the string is in
 * @returns {string} hex
 */
export function to_hex(str: string, encoding?: string): string;
/**
 * encode a string to utf-8
 *
 * @param {string} str string to encode
 * @param {string} encoding encoding the string is in
 * @returns {string} utf-8
 */
export function to_utf8(str: string, encoding: string): string;
/**
 * encode a number to hex
 *
 * @param {number} n number to encode
 * @returns {string} hex
 */
export function num_to_hex(n: number): string;
/**
 * decode a number from hex
 *
 * @param {string} h hex to decode
 * @returns {number} number
 */
export function hex_to_num(h: string): number;