FA-79579 / Barcode symbology encoding / Member archive

GS1-128 inserts FNC1 after fixed-length fields · case 04

Labels waste a symbol character after every GTIN and date and some parsers reject the extra separator.

Member previewVariant 4 · 3 implementations · 8 checks per implementation

Case contract

Assemble GS1-128 data from [AI, value] pairs; "#" stands for FNC1. The string starts with FNC1. Predefined fixed-length AIs: 00 (18), 01 and 02 (14), 11/13/15/17 (6), 3103 (6); variable-length AIs with maximum length: 10 and 21 (20), 30 and 37 (8), 400 (30). Numeric AIs: 00, 01, 02, 11, 13, 15, 17, 3103, 30, 37. Values use printable ASCII 33..126 except "#". A variable-length field is followed by FNC1 unless it is last. Errors: unknown-ai, bad-value.

Why this case matters

Retail, logistics, pharmacy and document workflows depend on encoders that produce exactly the module pattern, code-set switches, separators and quiet zones scanners expect; one misplaced module or separator makes a label unreadable or, worse, scan as different data.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
regression: separator after predefined-length fields 0	`"#0109162556501441#13875444"`	`"#010916255650144113875444"`	Failed

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