LZ78 Compression in Low Main Memory Space
نویسندگان
چکیده
We present the first algorithm that performs the LZ78 compression of a text of length n over alphabet [1..σ], whose output is z integers, using only O(z lg σ) bits of main memory. The algorithm reads the input text from disk in a single pass, and writes the compressed output to disk. The text can also be decompressed within the same main memory usage, which is unprecedented too. The algorithm is based on hashing and, under some simplifying assumptions, it runs in O(n) expected time. This is verified experimentally, together with the superiority of the algorithm with respect to previously implemented LZ78 compressors.
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تاریخ انتشار 2017