FA-52824 / Raster memory layout / Member archive

Chunked Row Groups: Group start omits intervening headers or directory prefix · case 04

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

Member previewVariant 4 · 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 3	`{"address": 519, "allocation_end": 829, "checksum": 544, "directory_bytes": 28, "group_count": 4, "group_id": 2, "group_origin": 474, "group_row": 0, "group_sizes": [206, 206, 206, 139], "row_span": 67}`	`{"address": 529, "allocation_end": 829, "checksum": 554, "directory_bytes": 28, "group_count": 4, "group_id": 2, "group_origin": 484, "group_row": 0, "group_sizes": [206, 206, 206, 139], "row_span": 67}`	Failed

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