zlib

File Format
Name	zlib
Ontology	Electronic File Formats Compression zlib
Released	1995

zlib format is a variant of the DEFLATE compressed data format. It adds a lightweight container, a small amount of configurability, and error checking.

zlib is also the name of a software library that supports the zlib format, and other formats related to DEFLATE.

There are many formats and protocols that use, or may use, zlib format. A notable example is PNG.

See also

• Adler-32
• DEFLATE

Identification

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.

Specifications

• ZLIB Specification v3.1 - No copy found. There are dead links to it in e.g. the zlib 0.95 README file.
• ZLIB Specification v3.2 (from archive.org)
• RFC 1950: ZLIB Compressed Data Format Specification version 3.3

Software

• zlib data compression library
• CloudFlare fork of zlib
• zlib-ng
• Puff - Lightweight decompression software included with zlib (contrib/puff)
• miniz
• zopfli - zlib compressor highly optimized for file size
• Offzip
• Deark

See also DEFLATE#Software.

Links

• Wikipedia article