FA-52828 / Raster memory layout / Member archive

Chunked Row Groups: Row-group pixel access reads header or ignores preceding checksums · case 03

The returned physical layout descriptor disagrees with the declared buffer mapping at address.

Member previewVariant 3 · 3 implementations · 6 checks per implementation

Case contract

Rows are grouped in packets of three scanlines. Each group has a five-byte header and every full allocated row has a two-byte checksum. Last group stores only actual rows, with a seven-byte directory record per group. Return the named intermediate layout descriptor and final address fields; all quantities are integer byte offsets unless explicitly stated.

Why this case matters

Offline raster resource, upload, readback, and storage-layout regression model.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
layout fixture 1	`{"address": 40, "allocation_end": 51, "checksum": 49, "directory_bytes": 7, "group_count": 1, "group_id": 0, "group_origin": 40, "group_row": 0, "group_sizes": [11], "row_span": 6}`	`{"address": 45, "allocation_end": 51, "checksum": 49, "directory_bytes": 7, "group_count": 1, "group_id": 0, "group_origin": 40, "group_row": 0, "group_sizes": [11], "row_span": 6}`	Failed

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