Pre-existing on main. The reader computed the position of a directory's next-IFD pointer before it
checked that every declared entry had been read: a saturating multiplication of the declared count,
then an unchecked addition. A 44-byte BigTIFF declaring u64::MAX entries therefore panicked with
overflow checks on. The position is now computed only for a directory read whole, with checked
arithmetic.
32-bit note: the same guard compared the counts after narrowing the declared one to usize, so on
wasm32 a BigTIFF declaring 4,294,967,297 entries but holding one passed for a whole directory and its
next pointer was followed. The counts now compare as 64-bit numbers (reads_every_entry). On wasm32 the
old comparison followed all six malformed test chains and the new one follows none; 64-bit results
are unchanged for every directory whose count is read whole.
Regression tests (crates/tiff/src/reader.rs):
a_bigtiff_directory_declaring_u64_max_entries_parses_without_overflow, which panicked before;
a_bigtiff_count_past_u32_max_never_follows_the_next_pointer (the whole chain, on every target); and
only_a_directory_read_whole_has_a_next_pointer (the comparison itself, on every target).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Sony ARWs record shading, lateral chromatic aberration and distortion as a camera setting plus a radial
table in the raw image IFD (0x7031-0x7037), with copies in the encrypted SR2SubIFD (0x797c-0x7982).
They are now decoded for every body that records them and carried through RawInfo and RawImage as
`lens_metadata.sony` (types in crates/raw/src/lens_metadata.rs, decoder in
crates/raw/src/vendor/arw_lens.rs):
- Raw-IFD fields are the ones the TIFF reader parsed, which is what the image itself uses. A scan of
the directory adds diagnostics only: repeated tags, and why an entry the reader skipped was dropped
(values outside the file, an unknown type, past the reader's limits). SR2SubIFD fields are read
from their first entry. Only the exact layouts are accepted: SHORT[1] or non-negative SSHORT[1]
settings, SSHORT[17] headed by 16 for shading and distortion, SSHORT[33] headed by 32 for CA.
Nothing is allocated from a count in the file.
- The raw IFD's copy wins. The SR2SubIFD copy fills in only for a tag the raw IFD lacks, never for a
malformed one, and the two copies' agreement is recorded.
- Settings keep their number and their documented meaning, Unknown(value) otherwise (never Off).
- Framing evidence (stored frame, Sony and default crops, reference rectangle, coding, 3:2) and a
per-component status. Only Applied components become opcodes.
Applied corrections are unchanged: the ILCE-7RM4A distortion conversion receives exactly the table it
received before, and no other body or component gains a correction. The ILCE-7CR distortion misses its
camera JPEG at 24 mm, and shading and CA semantics are not validated on any body; see
docs/sony-lens-corrections.md.
Locating the SR2SubIFD, now done for every ARW that has one, selects the SR2Private offset, length and
key with the TIFF reader's own rules, which lightcraft-tiff now exposes and builds its reader on
(directory_entries, entry_span, ParseOptions::budget_for, decode_value). Only each field's first value
is decoded, so the directory's other entries cost no memory sized by the file: a 16 MiB file whose
SR2Private holds eight fields aliasing it peaks at 37 kB. DirectoryEntries keeps its layout private,
and its positions() iterator uses checked arithmetic.
Tests: synthetic decoder tests; a differential test of the SR2Private selection against the TIFF
reader's in both byte orders (0 to 8,193 filler entries, unreadable and unusual first occurrences of
each field, a used-up value budget); a dhat peak-heap test; public-corpus checks against the values
ExifTool prints, with pinned and anchored SHA-256s (LIGHTCRAFT_CORPUS_REQUIRED=1 makes absent files
fail); and an opt-in local inventory check (crates/raw/tests/sony_lens_inventory.rs).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The D1X/D1H raw SubIFD is 4028x1324 with XResolution 600 / YResolution 300:
the pixel is twice as tall as it is wide. Nothing read that, so the
picture came out about 3:1. Add a pixel aspect to RawImage/RawInfo, read
it from the raw IFD resolution ratio (NEF) and from DefaultScale (DNG),
accept only 1.5..4, and resample the rows after demosaic. developed_size()
reports the stretched size, binning is off for non-square pixels, and the
catalog and lens-profile sizing use developed_size().
crates/raw/tests/robust.rs only mutated DNGs. Add two small valid CR3
fixtures (a 4x4 lossless CRX and a 16x16 three-level C-RAW CRX) and a
property that flips bytes in them or truncates them, then runs the existing
exercise() helper (probe, embedded_preview, decode, develop and the colour
transform) plus probe_info, the header-only description used on import:
errors or clean decodes, never a panic. Unlike random TIFF-like bytes, a
structurally valid file gets past the container walk, so the mutations land
in the CRX marker walker and entropy readers. A fixture test asserts that
both files decode as built, so the mutations hit live decode paths.
Tests only; the existing DNG property keeps its 400 cases and the new one
uses proptest's default (256, PROPTEST_CASES overrides it).
DNG export gains a "Lossy" compression: the raw data is demosaiced to linear
camera RGB (OpcodeList3 and the default crop applied), scaled to the resize long
edge when one is set, and stored as 8-bit baseline JPEG tiles at the export
quality. The codes follow a 1/2.2 power curve that a LinearizationTable maps
back to linear 16-bit values; colour matrices, white balance and the profile
look are kept. Available in the export dialog, `app.export`
(`dngCompression: "lossy"`) and the MCP export tool.
Also fixes a new clippy lint (chunks_exact_to_as_chunks) in pipeline/spots.rs
that fails `cargo xtask ci` on Rust 1.99.
Sources: Adobe DNG Specification 1.4+ (Compression 34892, LinearizationTable);
own design for the code curve.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Brandon Thomas