/**
 * Base64 / binary data / UTF-8 strings utilities
 *
 * It ensures that UTF-8 characters are used when encoding to Base64.
 *
 * Based on code of: <https://developer.mozilla.org/en-US/docs/Web/JavaScript/Base64_encoding_and_decoding>
 *
 * @module
 *
 * @example Encode string to Base64
 * ```ts
 * import { encodeBase64 } from "apprt-core/base64";
 *
 * const base64str = encodeBase64("hello world");
 * // base64str === "aGVsbG8gd29ybGQ="
 * ```
 *
 * @example Decode Base64 string
 * ```ts
 * import { decodeBase64 } from "apprt-core/base64";
 *
 * const str = decodeBase64("aGVsbG8gd29ybGQ=");
 * // str === "hello world"
 * ```
 */
/**
 * Encodes a string into a Base64-encoded string.
 * The string is first converted into a UTF-8 array and then encoded as Base64 string.
 * @param input a string to encode.
 * @returns Base64-encoded input
 */
declare function encodeBase64(input: string): string;
/**
 * Decodes a Base64 string into the raw string.
 * The Base64 string is first decoded into a UTF-8 array and then converted into a string.
 * @param input Base64 string.
 * @returns decoded input.
 */
declare function decodeBase64(input: string): string;
/**
 * Converts a Base64 string into a UTF-8 array.
 *
 * If your aim is to build a buffer of 16-bit / 32-bit / 64-bit raw data,
 * use the blocksSize argument, which is the number of bytes
 * of which the uint8Array.buffer.bytesLength property must result a multiple.
 * - 1 or omitted for ASCII, binary strings
 *   (i.e., a string in which each character in the string is treated as a byte of binary data)
 *   or UTF-8-encoded strings,
 * - 2 for UTF-16 strings,
 * - 4 for UTF-32 strings
 * @param base64Input the base64 input
 * @param blocksSize 1, 2 or 4 see above.
 * @returns decoded bytes.
 */
declare function base64DecodeToUtf8Arr(base64Input: string, blocksSize?: number): Uint8Array;
/**
 * Encodes a byte array into a Base64 string representation.
 * @param utf8Array array of bytes.
 * @returns Base64 string
 */
declare function base64EncodeUtf8Arr(utf8Array: Uint8Array): string;
/**
 * Converts a UTF-8 byte array into a string.
 * @param utf8Array byte array.
 * @returns string.
 */
declare function utf8ArrToStr(utf8Array: Uint8Array): string;
/**
 * Converts a string into a UTF-8 byte array.
 * @param input string to encode as UTF-8 bytes.
 * @returns UTF-8 byte array.
 */
declare function strToUtf8Arr(input: string): Uint8Array;

export { base64DecodeToUtf8Arr, base64EncodeUtf8Arr, decodeBase64, encodeBase64, strToUtf8Arr, utf8ArrToStr };