zlib Home Site 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
zlib - Wikipedia The first public version of Zlib, 0 9, was released on 1 May 1995 and was originally intended for use with the libpng image library It is free software, distributed under the zlib License