| 摘要 |
PROBLEM TO BE SOLVED: To efficiently compress data and to improve its processing speed by compressing input data based on a first compressing method and compressing data which is compressed by means of the first compressing method based on the second compressing method through the use of compression informatioin which is obtained from the compression processing. SOLUTION: The redundant degree of input data is inspected in input order by byte unit, data is compressed in accordance with its run-length and also the frequency distribution of run-length is obtained. After the compression processing in input data against whole data is finished, its compression degree is checked. Unless a prescribed compression rate is obtained, a code with a short data length is assigned in order from the highest frequency order based on the frequency distribution of the run-length so as to execute alias encoding. A frequency distribution table (TABNLE) 308 is changed at the time of storing compression data in a compression data temporary storage area (TEMPCMPR) 310. |
