TelemetryDownloader
A C++ TCP file-transfer system with a custom 7-type binary packet protocol, a Stop-and-Wait ACK mechanism, and a byte-exact verified 1MB transfer, 32 passing tests.
The Problem
Reliable file transfer over raw TCP sockets means designing everything HTTP gives you for free: a packet protocol, acknowledgement semantics, connection lifecycle, and defenses against malformed input.
What I Built
A Winsock client-server pair with a custom 7-type binary protocol (HELLO, VERIFY, GET_STATUS, DATA, ACK, ERROR), Stop-and-Wait ACKs for reliable delivery, and a 5-state server lifecycle state machine with malformed-packet rejection, out-of-order command blocking, and RAII cleanup.
The Result
32 passing tests and 134+ assertions across three tiers, Catch2 unit tests on serialization round-trips, socket-lifecycle integration tests, and a byte-exact end-to-end test verifying 1MB transfer integrity.