/**
 * For decoding: given a length prefix code 0..23 and the value of its
 * extra bits, return the actual run length (≥ 1).
 */
export declare function lengthFromCode(code: number, extraBitsValue: number): number;
/**
 * For encoding: convert a desired run length into the prefix code +
 * extra-bits payload. Returns `null` if `length < 1` or `> MAX_LENGTH`.
 */
export declare function lengthToCode(length: number): {
  code: number
  extraBits: number
  extraValue: number
} | null;
/**
 * VP8L length-code helpers — symmetric to `distance.ts`, but for the
 * length component of an LZ77 backreference.
 *
 * Length codes occupy positions 256..279 in the green/length alphabet
 * (i.e. the green tree dispatches to a length code by emitting a symbol
 * ≥ 256). Each code resolves to a base length plus an extra-bits payload
 * using VP8L's own prefix scheme (spec §4.2.1.1, libwebp `PrefixDecode`)
 * — NOT deflate's tables:
 *
 *   code < 4:  value = code + 1, no extra bits
 *   code ≥ 4:  extra  = (code - 2) >> 1
 *              offset = (2 + (code & 1)) << extra
 *              value  = offset + extraBits + 1
 *
 * The same scheme drives the distance alphabet in `distance.ts`.
 */
/** Length codes in the alphabet (positions 256..279 of the green tree). */
export declare const NUM_LENGTH_CODES: 24;
/** Extra-bit count per length code: (code - 2) >> 1 for codes ≥ 4. */
export declare const LENGTH_EXTRA_BITS: Uint8Array;
/** Base length for each code; final length = base + extraBitsValue. */
export declare const LENGTH_OFFSET: Uint16Array;
/** Maximum length representable in a single backreference. */
export declare const MAX_LENGTH: unknown;