import type { EncodedQuadTerms } from '../PatternTerm';
import type { IBTreeCandidates, RdfStoreIndexBTree } from './RdfStoreIndexBTree';
/**
 * Iterates over the quads of a {@link RdfStoreIndexBTree} that match a pattern, in index order.
 *
 * Components that the pattern binds after an unbound one are matched with a skip-scan: a quad that
 * does not match makes the scan jump ahead with a binary search rather than read on.
 *
 * The index may change while this iterates. The iterator then relocates itself after the last quad
 * it produced, so it neither repeats nor loses quads that were there all along.
 */
export declare class RdfStoreIndexBTreeIterator implements IterableIterator<EncodedQuadTerms<number>> {
    private readonly index;
    private readonly ids;
    private readonly levels;
    private readonly leading;
    private readonly candidates;
    private cursor;
    private version;
    private last;
    private done;
    /**
     * @param index The index to iterate over.
     * @param ids The encoded terms to match, of which only the entries at `levels` are considered.
     * @param levels The levels that must match, in ascending order.
     * @param leading The number of levels that are bound to a single term from the first one onwards without a gap.
     * @param candidates For levels with a quoted triple pattern, the quoted triples it matches.
     */
    constructor(index: RdfStoreIndexBTree, ids: (number | undefined)[], levels: number[], leading: number, candidates?: (IBTreeCandidates | undefined)[]);
    private resync;
    /**
     * Skip forward to the first result whose component at `level` is not before the sought term.
     *
     * Only quads that share the components before `level` with the next quad are skipped, and they are
     * found by binary search, so skipping costs logarithmic time in the number of skipped quads.
     * @param level The level to skip within.
     * @param isBefore Whether a key at that level precedes the sought term.
     */
    seek(level: number, isBefore: (key: number) => boolean): void;
    [Symbol.iterator](): IterableIterator<EncodedQuadTerms<number>>;
    next(): IteratorResult<EncodedQuadTerms<number>>;
    return(): IteratorResult<EncodedQuadTerms<number>>;
}