| 摘要 |
This invention enables lossless data compression at high speed while taking advantage of high-speed decompression. First, a dictionary area is reserved and initialized (step 601). The dictionary area is constructed with first and second storage areas. The first storage area stores the first 2 bytes of data read in accordance with a reading pointer as an index, and holds 0 if data subsequent to the third byte of the read data has not occurred in previous input data, but if the data has occurred in the previous input data, holds address information of the second storage area storing information related to this subsequent data. The second storage area stores the subsequent 1-byte data, and a first address storing a position of previous input data that matches the read 3-byte data, and holds 0 if there is no other pattern for the subsequent 1-byte data, or if there is, holds an address for chain-linking the area with another second storage area storing data for another pattern. When there is previous input data that matches the 3-byte data including the second storage area, data subsequent to the fourth byte of read data is compared with data located in the [position of previous input data+3 bytes], then a longest-match length L and address thereof are coded and outputted (step 606).
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