| 摘要 |
PURPOSE:To effectively utilize a memory without requiring a large-capacity memory by converting a data sequence having the same pattern into short codes and thus compressing the data sequence. CONSTITUTION:The data sequence from an input data file 1 is stored in a buffer memory 2 and a compression pointer PC1 and a comparison pointer PM1 are set. The comparison pointer PM1 is moved, byte by byte, to a limit area in the opposite direction from the compression pointer PC1, and whether or not the data sequence indicated by the compression pointer PC1 and the data sequence indicated by the comparison pointer PM match each other is checked. When coincidence length which is longer than previous coincidence length is detected, the previous coincidence length and coincidence position are updated and the new coincidence length and coincidence position are converted into specific codes, which are stored in a compressed data file 4. |
