| < draft-deutsch-gzip-spec-02.txt | draft-deutsch-gzip-spec-03.txt > | |||
|---|---|---|---|---|
| INTERNET-DRAFT L. Peter Deutsch | INTERNET-DRAFT L. Peter Deutsch | |||
| GZIP 4.3 Aladdin Enterprises | GZIP 4.3 Aladdin Enterprises | |||
| Expires: 16 Sep 1996 11 Mar 1996 | Expires: 26 Sep 1996 21 Mar 1996 | |||
| GZIP file format specification version 4.3 | GZIP file format specification version 4.3 | |||
| File draft-deutsch-gzip-spec-02.txt | File draft-deutsch-gzip-spec-03.txt | |||
| Status of this Memo | Status of this Memo | |||
| This document is an Internet-Draft. Internet-Drafts are working | This document is an Internet-Draft. Internet-Drafts are working | |||
| documents of the Internet Engineering Task Force (IETF), its areas, | documents of the Internet Engineering Task Force (IETF), its areas, | |||
| and its working groups. Note that other groups may also distribute | and its working groups. Note that other groups may also distribute | |||
| working documents as Internet-Drafts. | working documents as Internet-Drafts. | |||
| Internet-Drafts are draft documents valid for a maximum of six months | Internet-Drafts are draft documents valid for a maximum of six months | |||
| and may be updated, replaced, or obsoleted by other documents at any | and may be updated, replaced, or obsoleted by other documents at any | |||
| skipping to change at line 30 ¶ | skipping to change at line 30 ¶ | |||
| material or to cite them other than as ``work in progress.'' | material or to cite them other than as ``work in progress.'' | |||
| To learn the current status of any Internet-Draft, please check the | To learn the current status of any Internet-Draft, please check the | |||
| ``1id-abstracts.txt'' listing contained in the Internet- Drafts | ``1id-abstracts.txt'' listing contained in the Internet- Drafts | |||
| Shadow Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe), | Shadow Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe), | |||
| munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or | munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or | |||
| ftp.isi.edu (US West Coast). | ftp.isi.edu (US West Coast). | |||
| Distribution of this memo is unlimited. | Distribution of this memo is unlimited. | |||
| A pointer to the latest version of this and related documentation in | ||||
| HTML format can be found at the URL | ||||
| <ftp:ftp.uu.net/pub/graphics/png/documents/zlib/zdoc-index.html>. | ||||
| Notices | Notices | |||
| Copyright (c) 1996 L. Peter Deutsch | Copyright (c) 1996 L. Peter Deutsch | |||
| Permission is granted to copy and distribute this document for any | Permission is granted to copy and distribute this document for any | |||
| purpose and without charge, including translations into other | purpose and without charge, including translations into other | |||
| languages and incorporation into compilations, provided that it is | languages and incorporation into compilations, provided that the | |||
| copied as a whole (including the copyright notice and this notice) | copyright notice and this notice are preserved, and that any | |||
| and with no changes. | substantive changes or deletions from the original are clearly | |||
| marked. | ||||
| Deutsch [Page 1] | Deutsch [Page 1] | |||
| Abstract | Abstract | |||
| This specification defines a lossless compressed data format that is | This specification defines a lossless compressed data format that is | |||
| compatible with the widely used GZIP utility. The format includes a | compatible with the widely used GZIP utility. The format includes a | |||
| cyclic redundancy check value for detecting data corruption. The | cyclic redundancy check value for detecting data corruption. The | |||
| format presently uses the DEFLATE method of compression but can be | format presently uses the DEFLATE method of compression but can be | |||
| easily extended to use other compression methods. The format can be | easily extended to use other compression methods. The format can be | |||
| implemented readily in a manner not covered by patents. | implemented readily in a manner not covered by patents. | |||
| skipping to change at line 64 ¶ | skipping to change at line 69 ¶ | |||
| 1.2. Intended audience ......................................... 3 | 1.2. Intended audience ......................................... 3 | |||
| 1.3. Scope ..................................................... 3 | 1.3. Scope ..................................................... 3 | |||
| 1.4. Compliance ................................................ 3 | 1.4. Compliance ................................................ 3 | |||
| 1.5. Definitions of terms and conventions used ................. 3 | 1.5. Definitions of terms and conventions used ................. 3 | |||
| 1.6. Changes from previous versions ............................ 3 | 1.6. Changes from previous versions ............................ 3 | |||
| 2. Detailed specification ......................................... 4 | 2. Detailed specification ......................................... 4 | |||
| 2.1. Overall conventions ....................................... 4 | 2.1. Overall conventions ....................................... 4 | |||
| 2.2. File format ............................................... 5 | 2.2. File format ............................................... 5 | |||
| 2.3. Member format ............................................. 5 | 2.3. Member format ............................................. 5 | |||
| 2.3.1. Member header and trailer ........................... 5 | 2.3.1. Member header and trailer ........................... 5 | |||
| * 2.3.1.1. Extra field ...................... 8 | 2.3.1.1. Extra field ................................... 8 | |||
| * 2.3.1.2. Compliance ....................... 9 | 2.3.1.2. Compliance .................................... 9 | |||
| 3. References .................................................. 9 | 3. References .................................................. 9 | |||
| 4. Security considerations .................................... 10 | 4. Security considerations .................................... 10 | |||
| 5. Acknowledgements ........................................... 10 | 5. Acknowledgements ........................................... 10 | |||
| 6. Author's address ........................................... 10 | 6. Author's address ........................................... 10 | |||
| 7. Appendix: Jean-loup Gailly's gzip utility .................. 11 | 7. Appendix: Jean-loup Gailly's gzip utility .................. 11 | |||
| 8. Appendix: Sample CRC Code .................................. 11 | 8. Appendix: Sample CRC Code .................................. 11 | |||
| 1. Introduction | 1. Introduction | |||
| 1.1. Purpose | 1.1. Purpose | |||
| skipping to change at line 437 ¶ | skipping to change at line 442 ¶ | |||
| [1] "Information Processing - 8-bit single-byte coded graphic | [1] "Information Processing - 8-bit single-byte coded graphic | |||
| character sets - Part 1: Latin alphabet No.1" (ISO 8859-1:1987). | character sets - Part 1: Latin alphabet No.1" (ISO 8859-1:1987). | |||
| The ISO 8859-1 (Latin-1) character set is a superset of 7-bit | The ISO 8859-1 (Latin-1) character set is a superset of 7-bit | |||
| ASCII. Files defining this character set may be obtained from | ASCII. Files defining this character set may be obtained from | |||
| ftp.uu.net:/graphics/png/documents/iso_8859-1.* | ftp.uu.net:/graphics/png/documents/iso_8859-1.* | |||
| [2] ISO 3309 | [2] ISO 3309 | |||
| [3] ITU-T recommendation V.42 | [3] ITU-T recommendation V.42 | |||
| [4] Deutsch, L.P.,"'Deflate' Compressed Data Format Specification". | [4] Deutsch, L.P.,"'Deflate' Compressed Data Format Specification", | |||
| available in ftp.uu.net:/pub/archiving/zip/doc/deflate-*.doc | available in ftp.uu.net:/pub/archiving/zip/doc/deflate-*.doc | |||
| [5] Gailly, J.-L., gzip documentation, available in | [5] Gailly, J.-L., gzip documentation, available in | |||
| prep.ai.mit.edu:/pub/gnu/gzip-*.tar | prep.ai.mit.edu:/pub/gnu/gzip-*.tar | |||
| [6] Sarwate, D.V., "Computation of Cyclic Redundancy Checks via Table | [6] Sarwate, D.V., "Computation of Cyclic Redundancy Checks via Table | |||
| Look-Up", Communications of the ACM, 31(8), pp.1008-1013. | Look-Up", Communications of the ACM, 31(8), pp.1008-1013. | |||
| [7] Schwaderer, W.D., "CRC Calculation", April 85 PC Tech Journal, | [7] Schwaderer, W.D., "CRC Calculation", April 85 PC Tech Journal, | |||
| pp.118-133. | pp.118-133. | |||
| End of changes. 6 change blocks. | ||||
| 8 lines changed or deleted | 13 lines changed or added | |||
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