ISO/IEC INTERNATIONAL STANDARD 22091 First edition 2002-09-15 Information technology Streaming Lossless Data Compression algorithm (SLDC) Technologies de I'information Algorithme de compression sans perte de données en mode continu (SDLC) Reference number ISO/IEC 22091:2002(E) IEC @ISO/IEC2002 IHS unde Not for Resale ISO/IEC 22091:2002(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not this area. Adobe is a trademark of Adobe Systems Incorporated. Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the ? ISO/IEC2002 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either IsO at the address below or IsO's member body in the country of the requester. ISO copyright office Case postale 56 : CH-1211 Geneva 20 Tel.+41 22 749 0111 Fax + 41 22 749 09 47 E-mail [email protected] Web www.iso.ch Printed in Switzerland CopyrihtInteratinal Oorganization for Standardization @ ISO/IEC 2002 - All rights reserved ted without license from IHS Not for Resale ISO/IEC 22091:2002(E) Contents 1 Scope 1 2 Conformance 1 3 Normative reference 1 4 Terms and definitions 1 4.1 Access Point 1 4.2 Control Symbol 1 4.3 Copy Pointer 1 4.4 data byte 1 4.5 Data Symbol 1 4.6 Displacement Field 1 4.7 Encoded Data Stream 1 4.8 Encoded Record 1 4.9 End Marker 2 4.10 End Of Record Symbol (EOR Symbol) 2 4.11 File Mark 2 4.12 File Mark Symbol 2 4.13 Flush Symbol 2 4.14 History Buffer 2 4.15 Literal 1 2 4.16 Literal 2 2 4.17 Matching String 22 4.18 Match Count 4.19 Match Count Field 222- 4.20 Pad 4.21 Record 4.22 Record Segment 22 4.23 Reset X Symbol 4.24 Reset 1 Symbol 2 4.25 Reset 2 Symbol 2 4.26 scheme 1 2 4.27 Scheme 1 Symbol 2 4.28 scheme 2 3 4.29 Scheme 2 Symbol 3 4.30 user data 3 5 Conventions and Notations 3 5.1 Representation of numbers 3 5.2 Names 3 6 Acronyms 3 7 Algorithm Overview 3 7.1 Scheme 1 Encoding 3 7.2 Scheme 2 Encoding 3 7.3 History Buffer 4 8 Encoding Specification 4 8.1 User Data 4 8.2 History Buffer 4 8.3 Encoded Data Stream 4 ili HS unde Not for Resale ISO/IEC 22091:2002(E) 8.3.1 Access Point 5 8.4 Data Symbols 5 8.4.1 Literal 1 Data Symbols 5 8.4.2 Copy Pointer Data Symbols 5 8.4.3 Literal 2 Data Symbols 6 8.5 Control Symbols 7 8.6 Pad 8 ISO/IEC2002-All rights reserved tworking permited without license from IHS Not for Resale ISO/IEC 22091:2002(E) Foreword ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commission) form the specialized system for worldwide standardization. National bodies that are members of ISO or IEC participate in the development of International Standards through technical committees established by the respective organization to deal with particular fields of technical activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the work. In the fieldofinformationtechnology,ISOandIEChaveestablishedajointtechnicalcommittee,ISO/IECJTC1. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3 The main task of the joint technical committee is to prepare International Standards. Draft International Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as an International Standard requires approval by at least 75 % of the national bodies casting a vote. Attention is drawn to the possibility that some of the elements of this Internatio