/**
 * Hash Operations Implementation
 * Provides Redis-compatible hash operations (HSET, HGET, HMSET, HMGET, HGETALL)
 * Requirements: 1.11
 */
import { CacheEngine } from './CacheEngine.js';
/**
 * HashOperations provides Redis-compatible hash operations.
 * Hashes are stored as JSON-serialized objects with base64-encoded values.
 *
 * Requirements:
 * - 1.11: Support HSET, HGET, HMSET, HMGET, and HGETALL commands for hash operations
 */
export declare class HashOperations {
    private readonly cacheEngine;
    constructor(cacheEngine: CacheEngine);
    /**
     * Serialize a hash (Map of field -> Buffer) to a JSON string for storage.
     * Each Buffer value is encoded as base64.
     */
    private serializeHash;
    /**
     * Deserialize a stored JSON string back to a Map of field -> Buffer.
     */
    private deserializeHash;
    /**
     * Get the current hash stored at key, or an empty Map if not exists.
     */
    private getHash;
    /**
     * Save a hash to the cache.
     */
    private saveHash;
    /**
     * Set a field in the hash stored at key.
     * If the key doesn't exist, a new hash is created.
     *
     * Requirements:
     * - 1.11: Support HSET command for hash operations
     *
     * @param key - The cache key
     * @param field - The field name within the hash
     * @param value - The value to set
     * @returns 1 if field is new, 0 if field was updated
     */
    hset(key: string, field: string, value: Buffer): Promise<number>;
    /**
     * Get the value of a field in the hash stored at key.
     *
     * Requirements:
     * - 1.11: Support HGET command for hash operations
     *
     * @param key - The cache key
     * @param field - The field name within the hash
     * @returns The field value, or null if the field or key doesn't exist
     */
    hget(key: string, field: string): Promise<Buffer | null>;
    /**
     * Set multiple fields in the hash stored at key.
     * If the key doesn't exist, a new hash is created.
     * Accepts either a Map or a Record (plain object).
     *
     * Requirements:
     * - 1.11: Support HMSET command for hash operations
     *
     * @param key - The cache key
     * @param fieldValues - Map or Record of field-value pairs to set
     */
    hmset(key: string, fieldValues: Map<string, Buffer> | Record<string, Buffer>): Promise<void>;
    /**
     * Get the values of multiple fields in the hash stored at key.
     *
     * Requirements:
     * - 1.11: Support HMGET command for hash operations
     *
     * @param key - The cache key
     * @param fields - The field names to retrieve
     * @returns Array of values in the same order as fields, null for missing fields
     */
    hmget(key: string, ...fields: string[]): Promise<(Buffer | null)[]>;
    /**
     * Get all fields and values in the hash stored at key.
     *
     * Requirements:
     * - 1.11: Support HGETALL command for hash operations
     *
     * @param key - The cache key
     * @returns Map of all field-value pairs, empty Map if key doesn't exist
     */
    hgetall(key: string): Promise<Map<string, Buffer>>;
}
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