GS1 EPC Tag Data Standard 1.6 - Indicod-Ecr

45084509451045114512451345144515451645174518451945204521452245234524452545264527452845294530453145324533453445354536453745384539454045414542454345444545454645474548then immediately followed by a Data section that uses the Packed-Object compactionmethod described in I.8.An ID Table entry that was designed for use with the Packed-Object compaction methodcan call for various types of auxiliary information beyond the complete indication of theID itself (such as bit fields to indicate a variable data length, to aid the data compactionprocess). All such bit fields are concatenated in this portion, in the order called for by theID List or Map. Note that the Aux Format section is identically defined, whether thePacked Object is an IDLPO or an IDMPO.An ID Table entry invokes Aux Format length bits for all entries that are not specified asfixed-length in the table (however, these length bits are not actually encoded if theycorrespond to the last data item encoded in the A/N subsection of a Packed Object). Thisinformation allows the decoding system to parse the decoded data into strings of theappropriate lengths. An encoded Aux Format length entry utilizes a variable number ofbits, determined from the specified range between the shortest and longest data stringsallowed for the data item, as follows:If a maximum length is specified, and the specified range (defined as the maximumlength minus the minimum length) is less than eight, or greater than 44, then lengthsin this range are encoded in the fewest number of bits that can express lengths withinthat range, and an encoded value of zero represents the minimum length specified inthe format string. For example, if the range is specified as from three to sixcharacters, then lengths are encoded using two bits, and ‘00’ represents a length ofthree.Otherwise (including the case of an unspecified maximum length), the value (actuallength – specified minimum) is encoded in a variable number of bits, as follows:Values from 0 to 14 (representing lengths from 1 to 15, if the specified minimumlength is one character, for example) are encoded in four bitsValues from 15 to 29 are encoded in eight bits (a prefix of ‘1111’ followed byfour bits representing values from 15 (‘0000’) to 29 (‘1110’)Values from 30 to 44 are encoded in twelve bits (a prefix of ‘1111 1111’ followedby four bits representing values from 30 (‘0000’) to 44 (‘1110’)Values greater than 44 are encoded as a twelve-bit prefix of all ‘1’s, followed byan EBV-6 indication of (value – 44).Notes: if a range is specified with identical upper and lower bounds (i.e., a range ofzero), this is treated as a fixed length, not a variable length, and no Aux Formatbits are invoked. If a range is unspecified, or has unspecified upper or lower bounds, then this istreated as a default lower bound of one, and/or an unlimited upper bound.I.8 Data sectionA Data section is always present in a Packed Object, except in the case of a DirectoryPacked Object or Directory Addendum Packed Object (which encode no data elements),Copyright ©2005- 2011 GS1 AISBL, All Rights Reserved. Page 180 of 218