Appendix C
Data Compression Using ZIP
ZIP is a simple matching algorithm using two sliding windows, called the base window and the look-ahead window. These two windows are placed side-by-side on the data file, where the look-ahead window goes ahead of the base window. ZIP scans the entire file by sliding these two windows and encoding data on the fly. In particular, ZIP finds the longest prefix 
of the data string contained in the look-ahead window that also appears in the base window. This string in the look-ahead window (if found) is a copy of 
in the base window, and so it can be uniquely identified by two attributes: (1) the distance between the location of the first character of 
in the base window and the location of the first character in the look-ahead window and (2) the length of 
. If the space needed to hold the values of these two attributes is smaller than the space needed to hold 
, we obtain a saving of space.
To implement this idea, we will need to distinguish the binary values ...
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