| 摘要 |
PROBLEM TO BE SOLVED: To reduce the size of a dictionary used by the system which compresses and decompresses a data stream by generating a code with a dictionary address dedicated to a character string. SOLUTION: In a 1st stage 1, 2N English letters are inputted to the dictionary in advance. In a stage 2, the 1st letter of the data stream is read and substituted in a variable X1. In a stage 3, the next letter of the data stream is read and substituted in a variable X2. In a stage 4, a character string X1X2 is generated and retrieval from the dictionary is performed. If no object is found in it, the procedure is advanced to a stage 5. In the stage 5, a code equal to the contents of a counter is assigned to the character string X1X2 and then written in the dictionary. Then the counter is made to step, the code assigned to the contents of the variable X1 is outputted and the contents of the variable X2 are substituted in the variable X1. In a stage 6, a case wherein the character string X1X2 is found in the dictionary is controlled. |
