FA-79697 / Barcode symbology encoding / Member archive

QR terminator overflows a nearly full symbol · case 02

Payloads that fill all but a few bits get an extra codeword and the symbol is rejected as too long.

Member previewVariant 2 · 3 implementations · 8 checks per implementation

Case contract

Finish a QR data bit stream for a symbol with `capacity` data codewords: data longer than capacity*8 bits returns None; append a terminator of up to four 0 bits (truncated if capacity is reached), pad with 0 bits to a byte boundary, split into codewords, then append pad codewords alternating 0xEC, 0x11 starting with 0xEC until the capacity is filled.

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: terminator truncation at capacity 0	`[99, 8, 0]`	`[99, 8]`	Failed

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This record includes three runnable implementations, regression fixtures, execution results, and source hashes.

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