import { _PdfCrossReference } from './pdf-cross-reference';
import { _PdfDictionary, _PdfReferenceSetCache, _PdfReference } from './pdf-primitives';
/**
 * Provides access to the PDF catalog and utilities to traverse and cache the page tree.
 *
 * @private
 */
export declare class _PdfCatalog {
    private _crossReference;
    /**
     * Backing dictionary for the catalog object.
     *
     * @private
     */
    _catalogDictionary: _PdfDictionary;
    pageIndexCache: _PdfReferenceSetCache;
    pageKidsCountCache: _PdfReferenceSetCache;
    /**
     * Root pages dictionary of the document.
     *
     * @private
     */
    _topPagesDictionary: _PdfDictionary;
    /**
     * List of page indices that have been parsed and cached.
     *
     * @private
     */
    _parsedPages: number[];
    /**
     * Cache of page dictionaries and references keyed by page index.
     *
     * @private
     */
    _pageCache: Map<number, {
        dictionary: _PdfDictionary;
        reference: _PdfReference;
        parent: _PdfDictionary;
    }>;
    /**
     * Indicates whether the page tree format is invalid and requires linear traversal.
     *
     * @private
     */
    _hasInvalidPageTree: boolean;
    constructor(xref: _PdfCrossReference);
    readonly version: string;
    readonly pageCount: number;
    readonly acroForm: _PdfDictionary;
    /**
     * Creates and registers a new AcroForm dictionary on the catalog.
     *
     * @private
     * @returns {_PdfDictionary} The created AcroForm dictionary.
     */
    _createForm(): _PdfDictionary;
    private _addToCache;
    /**
     * Gets the page dictionary and reference for the specified page index, using caches when possible.
     *
     * @private
     * @param {number} pageIndex Zero-based page index to retrieve.
     * @returns {{ dictionary: _PdfDictionary, reference: _PdfReference }} The page dictionary and its indirect reference (if any).
     */
    _getPageDictionary(pageIndex: number): {
        dictionary: _PdfDictionary;
        reference: _PdfReference;
    };
    private _checkPageTreeFormat;
    private _findNearestIndex;
    private _traverseFromCached;
    private _findNextPage;
    private _traverseFromRoot;
    /**
     * Releases catalog and cache resources and clears references.
     *
     * @private
     */
    _destroy(): void;
}