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GZIP file format specification version 4.3 (RFC1952)

IP.com Disclosure Number: IPCOM000004180D
Original Publication Date: 1996-May-01
Included in the Prior Art Database: 2001-Nov-12
Document File: 13 page(s) / 25K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

P. Deutsch: AUTHOR

Abstract

This specification defines a lossless compressed data format that is compatible with the widely used GZIP utility. The format includes a cyclic redundancy check value for detecting data corruption. The format presently uses the DEFLATE method of compression but can be easily extended to use other compression methods. The format can be implemented readily in a manner not covered by patents. (Download file contains alternative document formats.)

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 15% of the total text.

Network Working Group                                         P. Deutsch

Request for Comments: 1952                           Aladdin Enterprises

Category: Informational                                         May 1996

               GZIP file format specification version 4.3

Status of This Memo

   This memo provides information for the Internet community.  This memo

   does not specify an Internet standard of any kind.  Distribution of

   this memo is unlimited.

IESG Note:

   The IESG takes no position on the validity of any Intellectual

   Property Rights statements contained in this document.

Notices

   Copyright (c) 1996 L. Peter Deutsch

   Permission is granted to copy and distribute this document for any

   purpose and without charge, including translations into other

   languages and incorporation into compilations, provided that the

   copyright notice and this notice are preserved, and that any

   substantive changes or deletions from the original are clearly

   marked.

   A pointer to the latest version of this and related documentation in

   HTML format can be found at the URL

   <ftp://ftp.uu.net/graphics/png/documents/zlib/zdoc-index.html>.

Abstract

   This specification defines a lossless compressed data format that is

   compatible with the widely used GZIP utility.  The format includes a

   cyclic redundancy check value for detecting data corruption.  The

   format presently uses the DEFLATE method of compression but can be

   easily extended to use other compression methods.  The format can be

   implemented readily in a manner not covered by patents.

Deutsch                      Informational                      [Page 1]

RFC 1952             GZIP File Format Specification             May 1996

Table of Contents

   1. Introduction ................................................... 2

      1.1. Purpose ................................................... 2

      1.2. Intended audience ......................................... 3

      1.3. Scope ..................................................... 3

      1.4. Compliance ................................................ 3

      1.5. Definitions of terms and conventions used ................. 3

      1.6. Changes from previous versions ............................ 3

   2. Detailed specification ......................................... 4

      2.1. Overall conventions ....................................... 4

      2.2. File format ............................................... 5

      2.3. Member format ............................................. 5

          2.3.1. Member header and trailer ........................... 6

              2.3.1.1. Extra field ................................... 8

              2.3.1.2. Compliance .................................... 9

      3. References .................................................. 9

      4. Security Considerations .................................... 10

      5. Acknowledgements ........................................... 10

      6. Author's Address ........................................... 10

      7. Appendix: Jean-Loup Gailly's gzip utility .................. 11

      8. Appendix: Sample CRC Code .................................. 11

1. Introduction

   1.1. Purpose

      The purpose of this specification is to define a lossless

      compressed data format that:

          * Is independent of CPU type, operating system, fi...