✨[Feat] Sprint 3 TIFF and EXIF Core - #4

Summary

• add a shared JPEG-independent TIFF/EXIF decoder over bounded TIFF-only views
• validate II/MM byte order, magic 42, first IFD offsets, complete IFD tables, and inline versus offset values
• support BYTE, ASCII, SHORT, LONG, RATIONAL, UNDEFINED, SLONG, and SRATIONAL
• traverse IFD0, ExifIFD, GPSIFD, and next-IFD links through an iterative FIFO queue
• enforce per-IFD entry, depth, total work, value-size, and decoded-component limits
• reject cyclic/repeated IFD offsets and recover around individual invalid entries
• decode a small common IFD0/ExifIFD/GPS tag set with exact rational values
• preserve duplicate and unknown tags structurally; keep MakerNote opaque
• integrate decoded child entries and relocated source paths/diagnostics into JPEG EXIF inspection

Diagnostics

TIFF_TRUNCATED_HEADER, TIFF_INVALID_BYTE_ORDER, TIFF_INVALID_MAGIC, TIFF_INVALID_FIRST_IFD_OFFSET, TIFF_TRUNCATED_IFD, TIFF_IFD_ENTRY_LIMIT_EXCEEDED, TIFF_IFD_DEPTH_LIMIT_EXCEEDED, TIFF_TRAVERSAL_LIMIT_EXCEEDED, TIFF_CYCLIC_IFD, TIFF_UNSUPPORTED_FIELD_TYPE, TIFF_INVALID_VALUE_RANGE, TIFF_INVALID_VALUE_OFFSET, TIFF_INVALID_POINTER, and TIFF_INVALID_RATIONAL.

Tests

• 16 test files, 155 tests passed
• little- and big-endian headers, empty IFDs, inline SHORT/BYTE/count-two values, and offset ASCII
• exact RATIONAL/SRATIONAL, zero denominators, unsigned LONG maximum, and signed LONG minimum
• ExifIFD and common GPS traversal, including big-endian GPS
• cycles, depth, per-IFD and total-work limits, truncated tables, invalid pointers/offsets, unsupported types, and extreme counts
• duplicates, unknown tags, opaque MakerNote, JPEG TIFF-base offsets, exact subviews, determinism, and input preservation

Deferred

No MakerNote or thumbnail decoding, arbitrary vendor tags, XMP/IPTC/ICC payload parsing, PNG/WebP integration, rewriting, cleaning, verification, decompression, image decoding, fuzzing, Rust, or WASM is included.

Validation

• npm run format:check — passed
• npm run lint — passed
• npm run typecheck — passed
• npm test — 16 files, 155 tests passed
• npm run build — ESM, source map, and declarations built
• npm audit — 0 vulnerabilities
• npm ls --omit=dev --depth=0 — 0 runtime dependencies
• npm pack --dry-run — expected 7-file, 30.1 kB package payload

Security review

All TIFF reads use the bounded reader. TIFF offsets remain relative to the TIFF subview. Complete IFD tables are validated before iteration; count multiplication is checked; traversal is iterative, depth/entry/total-work bounded, and cycle protected. No payload copies, input mutation, native bounds control flow, or runtime network/filesystem/DOM dependency was introduced.