zlib is a data compression library, and a general-purpose data compression format.
The zlib format is not the same as gzip format, but they are fairly similar, and both are supported by the zlib library.
The first byte of a zlib datastream has eight possible values: 0x08, 0x18, 0x28, ..., 0x78.
If the first two bytes are interpreted as a big-endian integer, it is always a multiple of 31.
- zlib data compression library
- zopfli - zlib compressor highly optimized for file size