![]() Instructions to generate the necessary Huffman tree immediately follow the block header. Most compressible data will end up being encoded using method 10, the dynamic Huffman encoding, which produces an optimized Huffman tree customized for each block of data individually. The stored block option adds minimal overhead and is used for data that is incompressible. 10: A dynamic Huffman compressed block, complete with the Huffman table supplied.01: A static Huffman compressed block, using a pre-agreed Huffman tree defined in the RFC.raw or literal) section, between 0 and 65,535 bytes in length Second and third bits: Encoding method used for this block type:.0: There are more blocks to process after this one.1: This is the last block in the stream.First bit: Last-block-in-stream marker:.Each block is preceded by a 3- bit header: The patent has since expired.Ī Deflate stream consists of a series of blocks. This led to its widespread use – for example, in gzip compressed files and PNG image files, in addition to the ZIP file format for which Katz originally designed it. As stated in the RFC document, an algorithm producing Deflate files was widely thought to be implementable in a manner not covered by patents. Patent 5,051,745, and assigned to PKWARE, Inc. Katz also designed the original algorithm used to construct Deflate streams. Deflate was later specified in RFC 1951 (1996). It was designed by Phil Katz, for version 2 of his PKZIP archiving tool. ![]() In computing, Deflate (stylized as DEFLATE) is a lossless data compression file format that uses a combination of LZ77 and Huffman coding.
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