GS1 EPC Tag Data Standard 1.6 - Indicod-Ecr

41424143414441454146default IDLPO Object Info format supports a sequence of one or more ID Lists, andeach such list begins with identifying information as to which registered table itrepresents (see I.5.1).If the second additional bit ‘A’ is ‘1’, then an Addendum subsection is present at theend of the Object Info section (see I.5.6).4147414841494150415141524153415441554156415741584159416041614162416341644165416641674168416941704171417241734174417541764177417841794180418141824183I.4.4 Patterns for use between Packed ObjectsThe appearance of ‘000001’ at the expected start of a Packed Object is used to indicateeither padding or a directory pointer, as follows: A following two-bit pattern of ‘11’ indicates that a Directory Packed Object Pointerfollows the pattern. The pointer is one or more octets in length, in EBV-8 format.This pointer may be Null (a value of zero), but if non-zero, indicates the number ofoctets from the start of the pointer to the start of a Directory Packed Object (which ifeditable, shall be the first in its “chain”). For example, if the Format Flags byte for aDirectory Pointer is encoded at byte offset 1, the Pointer itself occupies bytesbeginning at offset 2, and the Directory starts at byte offset 9, then the Dir Ptr encodesthe value “7” in EBV-8 format. A Directory Packed Object Pointer may appearbefore the first Packed Object in memory, or at any other position where a PackedObject may begin, but may only appear once in a given data carrier memory, and (ifnon-null) must be at a lower address than the Directory it points to. The first octetafter this pointer may be padding (as defined immediately below), a new set ofFormat Flag patterns, or the start of an ID List Packed Object. A following two-bit pattern of ‘00’ indicates that the full eight-bit pattern of‘00000100’ serves as a padding byte, so that the next Packed Object may begin on adesired word or block boundary. This pattern may repeat as necessary to achieve thedesired alignment. A following two-bit pattern of ‘01’ as a run-length padding indicator, and shall beimmediately followed by an EBV-8 indicating the number of octets from the start ofthe EBV-8 itself to the start of the next Packed Object (for example, if the nextPacked Object follows immediately, the EBV-8 has a value of one). This mechanismeliminates the need to write many words of memory in order to pad out a largememory block. A following two-bit pattern of ‘10’ is Reserved.I.5 Object Info sectionEach Packed Object’s Object Info section contains both Length Information (the size ofthe Packed Object, in bits and in octets), and ID Values Information. A Packed Objectencodes representations of one or more data system Identifiers and (if a Data PackedObject) also encodes their associated data elements (AI strings, DI strings, etc). The IDValues information encodes a complete listing of all the Identifiers (AIs, DIs, etc)encoded in the Packed Object, or (in a Directory Packed Object) all the Identifiersencoded anywhere in memory.To conserve encoded and transmitted bits, data system Identifiers (each typicallyrepresented in data systems by either two, three, or four ASCII characters) is representedCopyright ©2005- 2011 GS1 AISBL, All Rights Reserved. Page 169 of 218