An apparatus includes: a storage storing data input and sliding stored data per input; first and second comparators comparing in parallel the input data with each stored data and obtaining a position of data matching the input data; first and second determiners each determining whether a stored data matches the input data; a holder holding the result by the first or second comparator; a generator generating a value representing the position; a generator obtaining a longest length of a matching data list of the stored data that match the input data compared by the second comparator and that is at positions consecutive over each input, and generating a value representing the length; a generator generating a value using the input data as is; and a generator generating a code including these values. The comparison by the second comparator is controlled based on the result by the first or second comparator.