import type { GlyphId } from "../../types.ts";
import type { Coverage } from "./coverage.ts";
/**
 * Set Digest - A Bloom filter for fast O(1) glyph membership rejection.
 *
 * Uses three 64-bit masks with different bit shifts (0, 4, 9) to minimize
 * false positives. This is the same technique used by HarfBuzz/rustybuzz.
 *
 * The digest allows us to quickly reject glyphs that are definitely NOT
 * in a lookup's coverage without doing expensive Coverage table lookups.
 */
export declare class SetDigest {
    private mask0;
    private mask1;
    private mask2;
    /**
     * Add a single glyph to the digest
     * @param glyphId - The glyph ID to add
     */
    add(glyphId: GlyphId): void;
    /**
     * Add a range of glyphs to the digest
     * @param start - Start glyph ID (inclusive)
     * @param end - End glyph ID (inclusive)
     */
    addRange(start: GlyphId, end: GlyphId): void;
    /**
     * Fast check if glyph MAY be in the set
     * @param glyphId - The glyph ID to check
     * @returns False if glyph is definitely NOT in the set, true if glyph MAY be in the set (false positives possible)
     */
    mayHave(glyphId: GlyphId): boolean;
    /**
     * Add all glyphs from a Coverage table to this digest
     * @param coverage - The coverage table containing glyphs to add
     */
    addCoverage(coverage: Coverage): void;
    /**
     * Check if this digest MAY intersect with another digest
     * @param other - The other digest to check intersection with
     * @returns False if there is definitely NO overlap, true if there MAY be overlap (false positives possible)
     */
    mayIntersect(other: SetDigest): boolean;
    /**
     * Get raw masks for external comparison
     * @returns Object containing the three internal mask values
     */
    getMasks(): {
        mask0: number;
        mask1: number;
        mask2: number;
    };
}
/**
 * Create a SetDigest from multiple Coverage tables (for a lookup with multiple subtables)
 * @param coverages - Array of coverage tables to combine into a single digest
 * @returns A new SetDigest containing all glyphs from all coverage tables
 */
export declare function createLookupDigest(coverages: Coverage[]): SetDigest;