| < draft-deutsch-zlib-spec-02.txt | draft-deutsch-zlib-spec-03.txt > | |||
|---|---|---|---|---|
| INTERNET-DRAFT L. Peter Deutsch | INTERNET-DRAFT L. Peter Deutsch | |||
| ZLIB 3.3 Aladdin Enterprises | ZLIB 3.3 Aladdin Enterprises | |||
| Expires: 16 Sep 1996 Jean-Loup Gailly | Expires: 26 Sep 1996 Jean-Loup Gailly | |||
| Info-Zip | Info-ZIP | |||
| 11 Mar 1996 | 21 Mar 1996 | |||
| ZLIB Compressed Data Format Specification version 3.3 | ZLIB Compressed Data Format Specification version 3.3 | |||
| File draft-deutsch-zlib-spec-02.txt | File draft-deutsch-zlib-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 32 ¶ | skipping to change at line 32 ¶ | |||
| 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 and Jean-loup Gailly | Copyright (c) 1996 L. Peter Deutsch and Jean-loup Gailly | |||
| 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 and Gailly [Page 1] | Deutsch and Gailly [Page 1] | |||
| Abstract | Abstract | |||
| This specification defines a lossless compressed data format. The | This specification defines a lossless compressed data format. The | |||
| data can be produced or consumed, even for an arbitrarily long | data can be produced or consumed, even for an arbitrarily long | |||
| sequentially presented input data stream, using only an a priori | sequentially presented input data stream, using only an a priori | |||
| bounded amount of intermediate storage. The format presently uses | bounded amount of intermediate storage. The format presently uses | |||
| the DEFLATE compression method but can be easily extended to use | the DEFLATE compression method but can be easily extended to use | |||
| other compression methods. It can be implemented readily in a manner | other compression methods. It can be implemented readily in a manner | |||
| skipping to change at line 130 ¶ | skipping to change at line 135 ¶ | |||
| able to accept and decompress any data set that conforms to all | able to accept and decompress any data set that conforms to all | |||
| the specifications presented here; a compliant compressor must | the specifications presented here; a compliant compressor must | |||
| produce data sets that conform to all the specifications presented | produce data sets that conform to all the specifications presented | |||
| here. | here. | |||
| 1.5. Definitions of terms and conventions used | 1.5. Definitions of terms and conventions used | |||
| byte: 8 bits stored or transmitted as a unit (same as an octet). | byte: 8 bits stored or transmitted as a unit (same as an octet). | |||
| (For this specification, a byte is exactly 8 bits, even on | (For this specification, a byte is exactly 8 bits, even on | |||
| machines which store a character on a number of bits different | machines which store a character on a number of bits different | |||
| from 8.) See below, for the numbering of bits within a byte. | from 8.) See below, for the numbering of bits within a byte. | |||
| 1.6. Changes from previous versions | 1.6. Changes from previous versions | |||
| Version 3.1 was the first public release of this specification. | Version 3.1 was the first public release of this specification. | |||
| In version 3.2, some terminology was changed and the Adler-32 | In version 3.2, some terminology was changed and the Adler-32 | |||
| sample code was rewritten for clarity. In version 3.3, the | sample code was rewritten for clarity. In version 3.3, the | |||
| support for a preset dictionary was introduced, and the | support for a preset dictionary was introduced, and the | |||
| specification was converted to Internet Draft style. | specification was converted to Internet Draft style. | |||
| Deutsch and Gailly [Page 3] | Deutsch and Gailly [Page 3] | |||
| skipping to change at line 319 ¶ | skipping to change at line 324 ¶ | |||
| identifier of a known preset dictionary. A decompressor may | identifier of a known preset dictionary. A decompressor may | |||
| ignore FLEVEL and still be compliant. When the zlib data format | ignore FLEVEL and still be compliant. When the zlib data format | |||
| is being used as a part of another standard format, a compliant | is being used as a part of another standard format, a compliant | |||
| decompressor must support all the preset dictionaries specified by | decompressor must support all the preset dictionaries specified by | |||
| the other format. When the other format does not use the preset | the other format. When the other format does not use the preset | |||
| dictionary feature, a compliant decompressor must reject any | dictionary feature, a compliant decompressor must reject any | |||
| stream in which the FDICT flag is set. | stream in which the FDICT flag is set. | |||
| 3. References | 3. References | |||
| [1] Deutsch, L.P.,"'Gzip' Compressed Data Format Specification". | [1] Deutsch, L.P.,"'Gzip' Compressed Data Format Specification", | |||
| available in ftp.uu.net:/pub/archiving/zip/doc/gzip-*.doc | available in ftp.uu.net:/pub/archiving/zip/doc/gzip-*.doc | |||
| [2] Thomas Boutell, "PNG (Portable Network Graphics) specification". | [2] Thomas Boutell, "PNG (Portable Network Graphics) specification", | |||
| available in ftp://ftp.uu.net/graphics/png/png* | available in ftp://ftp.uu.net/graphics/png/png* | |||
| [3] Deutsch, L.P.,"'Deflate' Compressed Data Format Specification". | [3] 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 | |||
| [4] Fletcher, J. G., "An Arithmetic Checksum for Serial | [4] Fletcher, J. G., "An Arithmetic Checksum for Serial | |||
| Transmissions," IEEE Transactions on Communications, Vol. COM-30, | Transmissions," IEEE Transactions on Communications, Vol. COM-30, | |||
| No. 1, January 1982, pp. 247-252. | No. 1, January 1982, pp. 247-252. | |||
| [5] ITU-T Recommendation X.224, Annex D, "Checksum Algorithms," | [5] ITU-T Recommendation X.224, Annex D, "Checksum Algorithms," | |||
| November, 1993, pp. 144, 145. (Available from | November, 1993, pp. 144, 145. (Available from | |||
| gopher://info.itu.ch). ITU-T X.244 is also the same as ISO 8073. | gopher://info.itu.ch). ITU-T X.244 is also the same as ISO 8073. | |||
| End of changes. 8 change blocks. | ||||
| 11 lines changed or deleted | 16 lines changed or added | |||
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