APPARATUS AND METHOD FOR VARIABLE LENGTH CODING BY HASH

摘要

PROBLEM TO BE SOLVED: To reduce the memory capacitance of a variable length code (VLC) hash table and to reduce computational complexity in variable length coding.

SOLUTION: A hash operating means 102 applies a first hash operation with a small computational complexity to key data (RUN, LEVEL and LAST) based on source data to directly find the address of a VLC hash table 103. The VLC hash table 103 is referred to by using the address to acquire table information, and the table information is separated by a table separating means to obtain a secondary key (KEY2). The KEY2 is compared with a secondary key calculated from the key data to judge whether the table information is corresponding to the key data. When the agreement is found, the variable length code and a code length are obtained. The secondary key is stored in the VLC hash table to reduce the memory capacitance of the table. The hash operation is used not to generate synonyms, such that measures to cope with synonyms are not required.

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