modem-transfer is Navop's built-in ZMODEM protocol engine. The caller owns all I/O and drives the protocol state machine. The Rust library target remains named zmodem2 so the existing terminal integration API does not need a broad rename.

This crate is fully no_std compatible and heapless.

Provenance

This crate is derived from zmodem2 0.7.2 by Jarkko Sakkinen, which is based on prior work by Aleksei Arbuzov in the zmodem crate.

Upstream: https://codeberg.org/jarkko/zmodem2

The upstream and retained source are licensed under MIT OR Apache-2.0. See LICENSE-MIT and LICENSE-APACHE.

Navop maintains interoperability fixes including negotiated ESCCTL escaping, ZFILE retry behavior, and stock lrzsz integration coverage.

OxideTerm was consulted only as a high-level architectural reference for keeping the protocol engine in a first-party workspace crate and separating it from the terminal UI, transport, and filesystem. No OxideTerm source code was copied or adapted. The protocol implementation in this crate remains Navop's maintained zmodem2-derived engine described above.

Usage

Create a Sender or Receiver, then loop on poll() and act on the returned Action:

Action::WriteWire(bytes) — write the bytes to the transport, then call wire_written(n) with the number of bytes accepted.
Action::ReadFile { offset, max_len } (sender) — read the requested file bytes and provide them with submit_file(data).
Action::WriteFile(bytes) (receiver) — persist the bytes, then call file_written(n).
Action::Event(event) — handle a protocol Event (file/session lifecycle).
Action::Idle — feed incoming transport bytes with submit_wire(bytes), or call timeout() if none arrive.

The sender offers files with start_file(FileInfo) and ends the session with finish(). Either side can abort().