DESCRIPTION: Zlib is a free, general-purpose, patent-free library for creating LZW archives.

zlib is designed to be a free, general-purpose, legally unencumbered -- that
is, not covered by any patents -- lossless data-compression library for use
on virtually any computer hardware and operating system.  The zlib data
format is itself portable across platforms.  Unlike the LZW compression
method used in Unix compress(1) and in the GIF image format, the compression
method currently used in zlib essentially never expands the data.  (LZW can
double or triple the file size in extreme cases.) zlib's memory footprint is
also independent of the input data and can be reduced, if necessary, at some
cost in compression.  A more precise, technical discussion of both points is
available on another page.

zlib was written by Jean-loup Gailly (compression) and Mark Adler
(decompression).  Jean-loup is also the primary author/maintainer of
gzip(1), the author of the comp.compression FAQ list and the former
maintainer of Info-ZIP's Zip; Mark is also the author of gzip's and UnZip's
main decompression routines and was the original author of Zip.  Not
surprisingly, the compression algorithm used in zlib is essentially the same
as that in gzip and Zip, namely, the `deflate' method that originated in
PKWARE's PKZIP 2.x.