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Lempel, Ziv, Storer, Szymanski (LZSS)

The LZSS method (Lempel, Ziv, Storer, Szymanski) is a lossless compression

for character strings in a text document. This method detects repeating strings, regardless of their length. The stored strings are compared with the text of the text document. If no string is detected, then the corresponding letter is stored as a single byte

. According to the procedure, a variable window of letter combinations is slid over the text.An example

of anencoding makes the procedure understandable. The word "transmit sensor" is coded according to this procedure as follows: Of the word Sendesensorik, since no byte has yet been output, the "S" is output first. The check with regard to the letter "S" results in a hit, but it makes little sense to register a hit from a single letter as a repetition. The "e" therefore follows, which in combination with the stored "S" becomes "Se

" and occurs a second time in this combination. If the third letter, the "n", is added to the "Se", a repetition results for the "Sen". These three bytes of the repetition are output in a pair of values and represent the compression. The advantages of the LZSS procedure can be seen better with longer text passages.

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Englisch: Lempel, Ziv, Storer, Szymanski - LZSS
Updated at: 01.04.2008
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