import type { ComparePdfOptions } from '../types/ComparePdfOptions.js';
import type { PdfInput } from '../types/PdfInput.js';
import type { AllowedInputRoot } from './types.js';
/**
 * Validates the type of the input file.
 *
 * Accepts a `Buffer`, `ArrayBuffer`, `SharedArrayBuffer`, or a string path. When
 * `allowedInputRoot` is configured, string paths must also resolve within that directory.
 * String paths are resolved and read directly so downstream filesystem errors become the
 * single source of truth for file access failures. Throws for any other input.
 */
export declare function normalizePdfInput(inputFile: unknown, inputLabel: 'actualPdf' | 'expectedPdf', allowedInputRoot?: AllowedInputRoot): PdfInput;
export declare function validateAllowedInputRoot(allowedInputRoot: ComparePdfOptions['allowedInputRoot']): AllowedInputRoot | undefined;