update(data) {
			const sha1 = this;
			if (typeof data === "string") {
				data = codec.utf8String.toBits(data);
			}
			const b = sha1._buffer = bitArray.concat(sha1._buffer, data);
			const ol = sha1._length;
			const nl = sha1._length = ol + bitArray.bitLength(data);
			if (nl > 9007199254740991) {
				throw new Error("Cannot hash more than 2^53 - 1 bits");
			}
			const c = new Uint32Array(b);
			let j = 0;
			for (let i = sha1.blockSize + ol - ((sha1.blockSize + ol) & (sha1.blockSize - 1)); i <= nl;
				i += sha1.blockSize) {
				sha1._block(c.subarray(16 * j, 16 * (j + 1)));
				j += 1;
			}
			b.splice(0, 16 * j);
			return sha1;
		}
Input several words to the hash.
@param {bitArray|String} data the data to hash.
@return this