deflatecompressed

DEFLATE is a lossless data compression algorithm that combines LZ77-style back-references with Huffman coding. It was designed by Phil Katz for PKZIP and later standardized by the IETF in RFC 1951 (1996). The DEFLATE format is widely used to compress data in formats and protocols such as gzip, zlib, PNG images, and ZIP archives. Data compressed with DEFLATE is often referred to as DEFLATE-compressed.

DEFLATE operates on a stream of blocks. Each block can be stored uncompressed, or compressed with either fixed Huffman codes or dynamic Huffman codes. Within a compressed block, data consists of literals and length/distance pairs that reference earlier data, enabling repeated sequences to be encoded efficiently. A 32-kilobyte sliding window provides the available match area for LZ77-style compression, and the Huffman codes describe literals and matches.

DEFLATE aims for a practical balance between compression ratio and speed and is fast to decode, making it suitable for real-time use and streaming. It performs well on common data such as text and many binary formats, but is less effective on data that is already compressed. Implementations exist in a wide range of programming languages and platforms.

Applications and standards. DEFLATE underpins gzip and zlib, and is a core component of ZIP archives, PNG images, and HTTP content encoding. It is defined in RFC 1951 and is widely implemented to ensure interoperability across software and systems.