GS1 EPC Tag Data Standard 1.6 - Indicod-Ecr

443644374438443944404441444244434444444544464447444844494450445144524453correctly reflect the end state of the chain of additions and deletions to the memorybank; an Addendum to the Directory is not utilized to perform this maintenance (aDirectory Addendum may only add new structural components, as described later inthis section). In contrast, when the edited parentless object is an ID List PackedObject or ID Map Packed Object, its ID List or ID Map cannot be updated to reflectthe end state of the aggregate Object (parents plus children).Although a “child” may be either an ID List or an ID Map Packed Object, only anIDLPO can indicate deletions or changes to the current set of fully-qualified IDValues and associated data that is embodied in the chain. When a child is an IDMPO, it shall only be utilized to add (not delete or modify)structural information, and shall not be used to modify existing information. In aDirectory chain, a child IDMPO may add new ID tables, or may add a newAuxMap section or subsections, or may extend an existing PO Index Table orObjectOffsets list. In a Data chain, an IDMPO shall not be used as an Addendum,except to add new ID Tables. When a child is an IDLPO, its ID list (followed by “EditingOp” bits) lists onlythose FQIDVs that have been deleted, added, or replaced, relative to thecumulative ID list from the prior Objects linked to it.44544455445644574458445944604461446244634464446544664467446844694470447144724473447444754476I.6 Secondary ID Bits sectionThe Packed Objects design requirements include a requirement that all of the data systemIdentifiers (AI’s, DI’s, etc.) encoded in a Packed Object’s can be fully recognized withoutexpanding the compressed data, even though some ID Values provide only a partiallyqualifiedIdentifier. As a result, if any of the ID Values invoke Secondary ID bits, theObject Info section shall be followed by a Secondary ID Bits section. Examples includea four-bit field to identify the third digit of a group of related Logistics AIs.Secondary ID bits can be invoked for several reasons, as needed in order to fully specifyIdentifiers. For example, a single ID Table entry’s ID Value may specify a choicebetween two similar identifiers (requiring one encoded bit to select one of the two IDs atthe time of encoding), or may specify a combination of required and optional identifiers(requiring one encoded bit to enable or disable each option). The available mechanismsare described in Annex J. All resulting Secondary ID bit fields are concatenated in thisSecondary ID Bits section, in the same order as the ID Values that invoked them werelisted within the Packed Object. Note that the Secondary ID Bits section is identicallydefined, whether the Packed Object is an IDLPO or an IDMPO, but is not present in aDirectory IDMPO.I.7 Aux Format sectionThe Aux Format section of a Data Packed Object encodes auxiliary information for thedecoding process. A Directory Packed Object does not contain an Aux Format section.In a Data Packed Object, the Aux Format section begins with “Compact-Parameter” bitsas defined in Table I.7-1.Table I.7-1: Compact-Parameter bit patternsBit Compaction method used in this Packed Object ReferenceCopyright ©2005- 2011 GS1 AISBL, All Rights Reserved. Page 178 of 218