FA-79831 / Barcode symbology encoding / Open access

Pharmacode bars are printed in generation order · case 01

Codes are mirrored, so asymmetric patterns scan as other values.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

Bars are emitted least significant first instead of reversed.

VERIFIED REPAIR

Reverse the generated bars so the most significant bar comes first.

Unsuccessful approach: Rotating one bar to the front is not a reversal.

Case contract

Encode an integer 3..131070 as a one-track Pharmacode: repeatedly, an even value adds a wide bar and becomes (n - 2) / 2, an odd value adds a narrow bar and becomes (n - 1) / 2, until zero; bars are read in the reverse order of generation (left to right). Width: narrow 1, wide 3, spaces 2 between bars. Return [pattern, width] or None outside the range.

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.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(n):
    if not isinstance(n, int) or n < 3 or n > 131070:
        return None
    bars = []
    while n > 0:
        if n % 2 == 0:
            bars.append('w')
            n = (n - 2) // 2
        else:
            bars.append('n')
            n = (n - 1) // 2
    pass
    width = sum(3 if b == 'w' else 1 for b in bars) + 2 * (len(bars) - 1)
    return [''.join(bars), width]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[[34, ['nnnww', 17]], [120, ['wwwnnw', 24]], [7, ['nnn', 7]], [30, ['wwww', 18]], [127, ['nnnnnnn', 19]], [1, None], [2, None], [306, ['nnwwnnww', 30]]], [[85, ['nwnwwn', 22]], [353, ['nwwnnnwn', 28]], [31, ['nnnnn', 13]], [126, ['wwwwww', 28]], [127, ['nnnnnnn', 19]], [1022, ['wwwwwwwww', 43]], [1, None], [306, ['nnwwnnww', 30]]], [[142, ['nnnwwww', 27]], [274, ['nnnwnnww', 28]], [15, ['nnnn', 10]], [63, ['nnnnnn', 16]], [255, ['nnnnnnnn', 22]], [14, ['www', 13]], [1, None], [396, ['wnnnwwnw', 30]]], [[157, ['nnwwwwn', 27]], [19, ['nwnn', 12]], [240, ['wwwnnnw', 27]], [3, ['nn', 4]], [254, ['wwwwwww', 33]], [127, ['nnnnnnn', 19]], [1, None], [143, ['nnwnnnn', 21]]], [[157, ['nnwwwwn', 27]], [228, ['wwnnwnw', 27]], [158, ['nnwwwww', 29]], [30, ['wwww', 18]], [6, ['ww', 8]], [1, None], [2, None], [225, ['wwnnnwn', 25]]]]
labels = ["regression: reading order of bars", "repair trap", "combined fault", "control", "control", "boundary", "boundary", "control"]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check("%s %d" % (labels[i % len(labels)], i), solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
regression: reading order of bars 0	`['wwnnn', 17]`	`['nnnww', 17]`	Failed
repair trap 1	`['wnnwww', 24]`	`['wwwnnw', 24]`	Failed
combined fault 2	`['nnn', 7]`	`['nnn', 7]`	Passed
control 3	`['wwww', 18]`	`['wwww', 18]`	Passed
control 4	`['nnnnnnn', 19]`	`['nnnnnnn', 19]`	Passed
boundary 5	`None`	`None`	Passed
boundary 6	`None`	`None`	Passed
control 7	`['wwnnwwnn', 30]`	`['nnwwnnww', 30]`	Failed

SHA-256 / 89fec83ae13f90b8d4ccb3a43b5bab8e68874edcdc61c8247ef45a29b3f2f727

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(n):
    if not isinstance(n, int) or n < 3 or n > 131070:
        return None
    bars = []
    while n > 0:
        if n % 2 == 0:
            bars.append('w')
            n = (n - 2) // 2
        else:
            bars.append('n')
            n = (n - 1) // 2
    bars.insert(0, bars.pop())
    width = sum(3 if b == 'w' else 1 for b in bars) + 2 * (len(bars) - 1)
    return [''.join(bars), width]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[[34, ['nnnww', 17]], [120, ['wwwnnw', 24]], [7, ['nnn', 7]], [30, ['wwww', 18]], [127, ['nnnnnnn', 19]], [1, None], [2, None], [306, ['nnwwnnww', 30]]], [[85, ['nwnwwn', 22]], [353, ['nwwnnnwn', 28]], [31, ['nnnnn', 13]], [126, ['wwwwww', 28]], [127, ['nnnnnnn', 19]], [1022, ['wwwwwwwww', 43]], [1, None], [306, ['nnwwnnww', 30]]], [[142, ['nnnwwww', 27]], [274, ['nnnwnnww', 28]], [15, ['nnnn', 10]], [63, ['nnnnnn', 16]], [255, ['nnnnnnnn', 22]], [14, ['www', 13]], [1, None], [396, ['wnnnwwnw', 30]]], [[157, ['nnwwwwn', 27]], [19, ['nwnn', 12]], [240, ['wwwnnnw', 27]], [3, ['nn', 4]], [254, ['wwwwwww', 33]], [127, ['nnnnnnn', 19]], [1, None], [143, ['nnwnnnn', 21]]], [[157, ['nnwwwwn', 27]], [228, ['wwnnwnw', 27]], [158, ['nnwwwww', 29]], [30, ['wwww', 18]], [6, ['ww', 8]], [1, None], [2, None], [225, ['wwnnnwn', 25]]]]
labels = ["regression: reading order of bars", "repair trap", "combined fault", "control", "control", "boundary", "boundary", "control"]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check("%s %d" % (labels[i % len(labels)], i), solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
regression: reading order of bars 0	`['nwwnn', 17]`	`['nnnww', 17]`	Failed
repair trap 1	`['wwnnww', 24]`	`['wwwnnw', 24]`	Failed
combined fault 2	`['nnn', 7]`	`['nnn', 7]`	Passed
control 3	`['wwww', 18]`	`['wwww', 18]`	Passed
control 4	`['nnnnnnn', 19]`	`['nnnnnnn', 19]`	Passed
boundary 5	`None`	`None`	Passed
boundary 6	`None`	`None`	Passed
control 7	`['nwwnnwwn', 30]`	`['nnwwnnww', 30]`	Failed

SHA-256 / 92dcdc96e17cbb514f121f97e8e0f6590837a0a410daa2bd5d8cd257fbe6a777

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(n):
    if not isinstance(n, int) or n < 3 or n > 131070:
        return None
    bars = []
    while n > 0:
        if n % 2 == 0:
            bars.append('w')
            n = (n - 2) // 2
        else:
            bars.append('n')
            n = (n - 1) // 2
    bars.reverse()
    width = sum(3 if b == 'w' else 1 for b in bars) + 2 * (len(bars) - 1)
    return [''.join(bars), width]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[[34, ['nnnww', 17]], [120, ['wwwnnw', 24]], [7, ['nnn', 7]], [30, ['wwww', 18]], [127, ['nnnnnnn', 19]], [1, None], [2, None], [306, ['nnwwnnww', 30]]], [[85, ['nwnwwn', 22]], [353, ['nwwnnnwn', 28]], [31, ['nnnnn', 13]], [126, ['wwwwww', 28]], [127, ['nnnnnnn', 19]], [1022, ['wwwwwwwww', 43]], [1, None], [306, ['nnwwnnww', 30]]], [[142, ['nnnwwww', 27]], [274, ['nnnwnnww', 28]], [15, ['nnnn', 10]], [63, ['nnnnnn', 16]], [255, ['nnnnnnnn', 22]], [14, ['www', 13]], [1, None], [396, ['wnnnwwnw', 30]]], [[157, ['nnwwwwn', 27]], [19, ['nwnn', 12]], [240, ['wwwnnnw', 27]], [3, ['nn', 4]], [254, ['wwwwwww', 33]], [127, ['nnnnnnn', 19]], [1, None], [143, ['nnwnnnn', 21]]], [[157, ['nnwwwwn', 27]], [228, ['wwnnwnw', 27]], [158, ['nnwwwww', 29]], [30, ['wwww', 18]], [6, ['ww', 8]], [1, None], [2, None], [225, ['wwnnnwn', 25]]]]
labels = ["regression: reading order of bars", "repair trap", "combined fault", "control", "control", "boundary", "boundary", "control"]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check("%s %d" % (labels[i % len(labels)], i), solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
regression: reading order of bars 0	`['nnnww', 17]`	`['nnnww', 17]`	Passed
repair trap 1	`['wwwnnw', 24]`	`['wwwnnw', 24]`	Passed
combined fault 2	`['nnn', 7]`	`['nnn', 7]`	Passed
control 3	`['wwww', 18]`	`['wwww', 18]`	Passed
control 4	`['nnnnnnn', 19]`	`['nnnnnnn', 19]`	Passed
boundary 5	`None`	`None`	Passed
boundary 6	`None`	`None`	Passed
control 7	`['nnwwnnww', 30]`	`['nnwwnnww', 30]`	Passed

SHA-256 / 1618f7da0c8df944f3ba406720708313a37cf96e5ca619e314406f5f97c7dfc0

Verification & scope

A deterministic bounded teaching model with a stipulated contract; it makes no claim of conformance to any published specification. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:49:48.212374+00:00.

Case digest / cc497b3a3dd30cfab52f07ebbeb1170976b55a3b3c98689786d1a4568cc01f3e