| 摘要 |
<p>A coding is carried out by designating the reference number of a partial sequence having the maximum length coincidence from the coded partial sequences registered in a dictionary with regard to a received character sequence, designating a new reference number to a partial sequence which is obtained by adding one character to a reference number obtained as a code word, and registering the new reference number designated partial sequence in the dictionary. A decoding is carried out by searching partial sequences registered in the dictionary using a code word represented by the reference number of the partial sequence, restoring the original partial sequence, designating a new reference number to a partial sequence which is obtained by adding the beginning character of the currently restored partial sequence to the previously processed code word, and registering the new reference number designated partial sequence in the dictionary. According to the invention, the following steps are provided : constituting a reference dictionary by a group of dictionaries comprising : a number of dictionaries less than the number of entire kinds of characters to be processed, and for each dictionary, initially registering character sequences which occur with higher frequency of occurrence and comprise one character of the entire kinds of characters per character or a plurality of characters per character with designations of reference numbers; coding the received character sequences by designating a specific dictionary from the group of dictionaries according to search information representing the dependency relation to coded character sequences; and if a received character sequence does not exist in the designated dictionary, registering a character sequence which is obtained by adding a sequence character to the reference number of a coded character sequence with a designation of a new reference number. <IMAGE></p> |
