import type { HeaderMap } from "./headers.js";
export type SupportedEncodings = {
    gzip(): boolean;
    deflate(): boolean;
    br(): boolean;
    zstd(): boolean;
};
/**
 * Represents various content encodings used for compression and decompression.
 *
 * This class is used to define well-known encoding formats, provide
 * functionality for parsing and resolving encodings based on client preferences
 * or available support and determine the preferred encoding from a list of
 * accepted encodings.
 *
 * Encodings are defined as static constants in this class, such as GZIP,
 * DEFLATE, etc. Each encoding includes a string identifier and an optional
 * file extension.
 *
 * Instances of this class cannot be directly instantiated and must be accessed
 * via the static constants or methods provided.
 */
export declare class Encoding {
    static readonly IDENTITY: Encoding;
    static readonly DEFLATE: Encoding;
    static readonly GZIP: Encoding;
    static readonly BROTLI: Encoding;
    static readonly ZSTD: Encoding;
    /**
     * Value of the encoding as represented in headers.
     */
    readonly value: string;
    /**
     * File extension associated with the encoding, if any.
     */
    readonly fileExtension: string | null;
    private constructor();
    /**
     * Determines the preferred encoding from the provided headers and
     * supported encodings.
     */
    static fromHeaders(headers: HeaderMap, supportedEncodings: SupportedEncodings): Encoding;
    /**
     * Determines the preferred encoding from a list of accepted encodings and
     * their associated quality values.
     */
    static preferredEncoding(acceptedEncodings: [Encoding, number][]): Encoding | null;
}
/**
 * Parses the `accept-encoding` headers and returns a list of pairings of
 * supported encodings and their associated quality values (q-values).
 */
export declare const encodings: (headers: HeaderMap, supportedEncodings: SupportedEncodings) => [Encoding, number][];
/**
 * Parses a Q-value string from an input and returns its numerical
 * representation.
 *
 * The Q-value string is a weight factor used in HTTP headers, typically in the
 * format "q=value", where the value is a floating-point number between 0 and 1
 * inclusive with up to three decimal places.
 *
 * The returned value is multiplied by 1000 to ensure it's an integer between
 * 0 and 1000 inclusive. If the input is invalid or the Q-value is not within
 * the valid range, null is returned.
 */
export declare const parseQValue: (value: string) => number | null;