FA-52805 / Raster memory layout / Member archive

Chunked Row Groups: Within-group scanline retains global row coordinate · case 05

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

Member previewVariant 5 · 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 2	`{"address": 87, "allocation_end": 587, "checksum": 141, "directory_bytes": 21, "group_count": 3, "group_id": 0, "group_origin": 76, "group_row": 0, "group_sizes": [191, 191, 129], "row_span": 62}`	`{"address": 211, "allocation_end": 587, "checksum": 265, "directory_bytes": 21, "group_count": 3, "group_id": 0, "group_origin": 76, "group_row": 2, "group_sizes": [191, 191, 129], "row_span": 62}`	Failed

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

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