@particle/tachyon-image

Shared library for Particle Tachyon system images. It is the single home for all image logic so the composer, CLI, on-device OTA service, and cloud server never re-implement it:

• operation-graph model (program chunked/sparse · erase · zero · patch GPT-arith · gpt)
• particle_image_v1 (Particle format) + legacy Qualcomm image_manifest_v1 parse/build
• rawprogram / patch / erase XML round-trip (import a real factory image, emit qdl-ready XML)
• ed25519 / JCS manifest signing + verification
• sha256 / payload_sha256 hashing (expanded-with-holes)
• Android sparse + multi-chunk decode
• format expansion: factory | ota-image(slot) | ota-boot(slot)
• manifest-first ZIP read/write (streaming, partition-decodable order)
• validation (shared by composer CI, cloud server, CLI)

Every module is unit-tested. Golden fixtures under test/fixtures/factory/ are real rawprogram/patch/manifest.json entries pulled from the published Tachyon factory image, used to prove lossless round-trip.

Prior art (reference, not a dependency)

The Qualcomm rawprogram/patch grammar is also implemented by linux-msm/qdl (C, BSD-3 — authoritative) and bkerler/edl (Python, GPL-3 — most complete parser). We read those for grammar edge cases (patch CRC ops, partofsingleimage, sparse/erase) but implement our own in TypeScript: no JS/TS library exists, it avoids the GPL/Python coupling, and we need a superset (op-graph + particle_image_v1 + signing) they don't provide.

Build & test

npm install
npm run build      # tsc -> dist/
npm test           # vitest
npm run typecheck