Data processing device, data processing method, and computer readable medium

A data processing method comprising:

• a region specifying process, by a computer, of specifying a first region where a regular bit string is in a transmission frame, a second region where a bit string similar to a defined bit string is in the transmission frame, and a third region where a non-regular bit string is in the transmission frame and extracting a difference between a bit string in the second region and the defined bit string;
• a first CRC acquisition process, by the computer, of acquiring, from a CRC table having a plurality of stored CRCs (Cyclic Redundancy Checks), a first CRC, which is a CRC corresponding to the regular bit string, for the first region;
• a second CRC acquisition process, by the computer, of acquiring, from the CRC table, a second CRC, which is a CRC corresponding to the defined bit string which is similar to the bit string in the second region;
• a differential CRC acquisition process, by the computer, of acquiring, from the CRC, a differential CRC, which is a CRC corresponding to the difference extracted between the bit string in the second region and the defined bit string;
• a third CRC generation process, by the computer, of generating a third CRC, which is a CRC corresponding to a bit string in the third region;
• and
• a frame CRC generation process, by the computer, of generating a CRC of the transmission frame by performing an exclusive logical operation using the first CRC, the second CRC, the differential CRC, and the third CRC;
• wherein in the region specifying process, the computer specifies, as the second region, a region of the transmission frame which has a bit string similar to any of the one or more defined bit strings, the number of defined bit strings and bit patterns of the defined bit strings being decided such that a target value is set for each of a number of differences and a table size of the CRC table and each difference is equal to or smaller than its set target value and the table size is equal to or smaller than its set target value.

A non-transitory computer readable medium storing a data processing program that causes a computer to execute:

• a region specifying process of specifying a first region where a regular bit string is in a transmission frame, a second region where a bit string similar to a defined bit string is in the transmission frame, and a third region where a non-regular bit string is in the transmission frame and extracting a difference between a bit string in the second region and the defined bit string;
• a first CRC acquisition process of acquiring, from a CRC table having a plurality of stored CRCs, a first CRC, which is a CRC (Cyclic Redundancy Check) corresponding to the regular bit string for the first region;
• a second CRC acquisition process of acquiring, from the CRC table, a second CRC, which is a CRC corresponding to the defined bit string which is similar to the bit string in the second region;
• a differential CRC acquisition process of acquiring, from the CRC table, a differential CRC, which is a CRC corresponding to the difference between the bit string in the second region and the defined bit string which is extracted by the region specifying process;
• a third CRC generation process of generating a third CRC, which is a CRC corresponding to a bit string in the third region;
• and
• a frame CRC generation process of generating a CRC of the transmission frame by performing an exclusive logical operation using the first CRC, the second CRC, the differential CRC, and the third CRC;
• wherein the data processing program causes the computer, in the region specifying process, to specify, as the second region, a region of the transmission frame which has a bit string similar to any of the one or more defined bit strings, the number of defined bit strings and bit patterns of the defined bit strings being decided such that a target value is set for each of a number of differences and a table size of the CRC table and each difference is equal to or smaller than its set target value and the table size is equal to or smaller than its set target value.