export declare class Rollsum {
    private s1;
    private s2;
    private window;
    private wofs;
    constructor();
    update(ch: number): void;
    private rollsumAdd;
    /**
     * Returns true if splitting is needed, that is when the current digest
     * reaches the given number of the same consecutive low bits.
     */
    split(mask: number): boolean;
}