/**
 * CMap parser for PDF text extraction.
 *
 * Parses /ToUnicode CMap programs to build character code → Unicode mappings.
 * This is essential for extracting text from PDFs that use CIDFonts or
 * custom encodings.
 *
 * Supports:
 * - beginbfchar / endbfchar (single character mappings)
 * - beginbfrange / endbfrange (range mappings, including array form)
 * - begincodespacerange / endcodespacerange
 * - Multi-byte character codes (1-4 bytes)
 * - UTF-16BE encoded target strings (including surrogate pairs)
 *
 * @see PDF Reference 1.7, §5.9 - ToUnicode CMaps
 * @see Adobe Technical Note #5411 - CMap Resources
 */
/**
 * A parsed CMap that maps character codes to Unicode strings.
 */
export declare class CMap {
    private codeSpaceRanges;
    private bfChars;
    private bfRanges;
    /** Number of bytes per character code (detected from codespace ranges) */
    bytesPerCode: number;
    constructor();
    /**
     * Look up the Unicode string for a character code.
     * Uses binary search over sorted bfRanges for efficient lookup.
     */
    lookup(code: number): string | undefined;
    /**
     * Add a code space range.
     */
    addCodeSpaceRange(low: number, high: number, bytes: number): void;
    /**
     * Add a bfchar mapping.
     */
    addBfChar(code: number, unicode: string): void;
    /**
     * Add a bfrange mapping.
     */
    addBfRange(low: number, high: number, mapping: string | string[]): void;
    /**
     * Sort bfRanges by low value for binary search.
     * Should be called after all ranges have been added.
     */
    sortRanges(): void;
    /**
     * Determine the code length (in bytes) for a given first byte,
     * using the codespace ranges. When multiple ranges match (e.g. a 1-byte
     * range covering 0x00-0xFF and a 2-byte range whose first byte overlaps),
     * returns the longest match per the PDF spec's greedy matching rule.
     * Falls back to bytesPerCode if no range matches.
     */
    getCodeLength(firstByte: number): number;
    /**
     * Check if this CMap has any mappings.
     */
    get isEmpty(): boolean;
    /**
     * Check if this CMap has codespace ranges defined.
     */
    get hasCodeSpaceRanges(): boolean;
}
/**
 * Parse a CMap program (typically from a /ToUnicode stream).
 */
export declare function parseCMap(data: Uint8Array): CMap;