/**
 * Options for encoding and decoding base64 strings.
 */
interface Base64Options {
    /** The base64 alphabet. Defaults to "base64" */
    alphabet?: Base64Alphabet;
}
/**
 * The base64 alphabets.
 */
type Base64Alphabet = "base64" | "base64url";
/**
 * Calculate the output size needed to encode a given input size for
 * {@linkcode encodeIntoBase64}.
 *
 * @param originalSize The size of the input buffer.
 * @returns The size of the output buffer.
 *
 * @example Basic Usage
 * ```ts
 * import { assertEquals } from "@std/assert";
 * import { calcSizeBase64 } from "@std/encoding/unstable-base64";
 *
 * assertEquals(calcSizeBase64(1), 4);
 * ```
 */
declare function calcSizeBase64(originalSize: number): number;

export { type Base64Options as B, type Base64Alphabet as a, calcSizeBase64 as c };