/** An object that knows how to prepend itself to an Encoder. */
export interface EncodableObj {
    encodeTo: (encoder: Encoder) => void;
}
/**
 * An encodable TLV structure.
 *
 * @remarks
 * First item is a number for TLV-TYPE.
 * Optional second item could be {@link Encoder.OmitEmpty} to omit the TLV if TLV-VALUE is empty.
 * Subsequent items are `Encodable`s for TLV-VALUE.
 */
export type EncodableTlv = [type: number, ...Encodable[]] | [
    type: number,
    omitEmpty: typeof Encoder.OmitEmpty,
    ...Encodable[]
];
/**
 * An object acceptable to {@link Encoder.encode}.
 *
 * @remarks
 * - `Uint8Array`: prepended as is.
 * - `undefined` and `false`: skipped.
 * - `EncodableObj`: `.encodeTo(encoder)` is invoked.
 * - `EncodableTlv`: passed to {@link Encoder.prependTlv}.
 * - `Encodable[]`: passed to {@link Encoder.prependValue}.
 */
export type Encodable = Uint8Array | undefined | false | EncodableObj | EncodableTlv | readonly Encodable[];
/** TLV encoder that accepts objects in reverse order. */
export declare class Encoder {
    constructor(initSize?: number);
    private buf;
    private off;
    /** Return encoding output size. */
    get size(): number;
    /** Obtain encoding output. */
    get output(): Uint8Array;
    /**
     * Make room to prepend an object.
     * @param sizeofObject - Object size.
     * @returns Room to write object.
     */
    prependRoom(sizeofObject: number): Uint8Array;
    /** Prepend TLV-TYPE and TLV-LENGTH. */
    prependTypeLength(tlvType: number, tlvLength: number): void;
    /**
     * Prepend TLV-VALUE.
     *
     * @remarks
     * Elements are prepended in the reverse order, so that they would appear in the output
     * in the same order as the parameter order.
     */
    prependValue(...tlvValue: Encodable[]): void;
    /**
     * Prepend TLV structure.
     * @see {@link EncodableTlv}
     */
    prependTlv(tlvType: number, ...tlvValue: Encodable[]): void;
    /**
     * Prepend TLV structure, but skip if TLV-VALUE is empty.
     * @see {@link EncodableTlv}
     */
    prependTlv(tlvType: number, omitEmpty: typeof Encoder.OmitEmpty, ...tlvValue: Encodable[]): void;
    /** Prepend `Encodable`. */
    encode(obj: Encodable): void;
    private grow;
}
export declare namespace Encoder {
    /**
     * Indicate that TLV should be skipped if TLV-VALUE is empty.
     * @see {@link EncodableTlv}
     */
    const OmitEmpty: unique symbol;
    /** Encode a single object into Uint8Array. */
    function encode(obj: Encodable, initBufSize?: number): Uint8Array;
    /**
     * Extract the encoding output of an element while writing to a parent encoder.
     * @param obj - Encodable element.
     * @param cb - Function to receive the encoding output of `obj`.
     * @returns Wrapped Encodable object.
     */
    function extract(obj: Encodable, cb: (output: Uint8Array) => void): Encodable;
}