FA-72228 / Error-correcting codes / Member archive

CRC correction presets the register to all ones · case 03

Clean frames are reported corrupted or "corrected" into different payloads.

Member previewVariant 3 · 3 implementations · 8 checks per implementation

Case contract

Frames of 2..15 bytes end with a CRC-8 (polynomial 0x07, initial value 0, MSB first, no final XOR) over the preceding bytes. A matching CRC is "clean"; otherwise try every single-bit flip across the whole frame, including the CRC byte, and accept the first that makes the CRC match ("corrected"). Otherwise "uncorrectable". Return [status, payload bytes or None].

Why this case matters

Sensor buses use short CRC-protected frames and correct single-bit upsets instead of retransmitting.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
regression [[167, 181, 81]]	`["uncorrectable", null]`	`["corrected", [167, 181]]`	Failed

MEMBER ARCHIVE

The complete case is available to members.

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

Member access is invitation-based. Sign in with your invited account to inspect the sources.