| 摘要 |
<P>PROBLEM TO BE SOLVED: To efficiently perform compression. <P>SOLUTION: When a data compression and restoration device 100 converts a character string S, a calculation cost is reduced by turning characters at and after an origin to substitution objects and limiting the area of the characters to be the substitution object. Also, the data compression and restoration device 100 does not store all the histories of substituted characters in a substitution history table, and stores only the origin, an offset and a return distance in the substitution history table. Further, since the information of the origin in the substitution history table can be uniquely derived from a relation between the offset and the return distance, the data compression and restoration device 100 reduces a data amount to be stored in a storage part 140 by storing the substitution history table from which the information of the origin is excluded in the storage part 140. <P>COPYRIGHT: (C)2012,JPO&INPIT |
