FA-79159 / Image orientation metadata / Member archive

Exif segment index is reported relative to the segment after SOI · case 04

The writer rewrites the segment before the Exif block when updating orientation.

Member previewVariant 4 · 3 implementations · 8 checks per implementation

Case contract

Input: JPEG segments as [marker, payload] with the payload as a latin-1 string. The stream must start with SOI (0xD8) or the result is "not-jpeg". Scan segments after SOI until SOS (0xDA) or EOI (0xD9); a payload longer than 65533 bytes cannot be encoded in the 16-bit length and yields "corrupt". Return the index of the first APP1 (0xE1) segment whose payload starts with "Exif\0\0", or None.

Why this case matters

Camera, phone and scanner images carry an orientation hint separately from the stored pixels; galleries, thumbnailers, editors and upload pipelines must interpret it consistently or photos appear sideways, mirrored or doubly rotated.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
regression: reported segment index 0	`0`	`1`	Failed

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