| 摘要 |
PURPOSE:To quickly encode data by referring to the frequency in appearance of the character string to transpose search trees of a dictionary in the frequency order at the time of progress of encoding to a certain degree and retrieving a character string through the shortest route hereafter. CONSTITUTION:Encoded data is divided into different partial strings and they are registered in a dictionary (memory) 10, and these partial strings are retrieved and compared with input data in accordance with a retrieval list 10a indicating the retrieval layer of partial strings to be connected, and input data is designated by the reference number of the maximum-length coinciding partial string out of partial strings in the dictionary 10 and is encoded. In this case, a count area where the frequency in retrieval is held and a carry flag area indicating overflow of the value in the count area are provided for each recorded partial string in the dictionary, and the corresponding count area is updated at the time of retrieval of each partial string, and carry flags are referred to transpose the retrieval order of partial strings. Thus, the character string is retrieved with the shortest route hereafter, and the encoding processing is quickly performed. |
