dart_udt

Pure-Dart-first, incremental port of UDT (UDP-based Data Transfer).

Status: pre-release (0.0.1-dev). The package already provides deterministic protocol, planner, and runtime-adapter building blocks, while full end-to-end UDT socket/session parity is still in progress.

Why this package

• Keep UDT behavior auditable while porting from upstream C++ (lib/src/upstream_udt_comment/).
• Prioritize deterministic, no-network tests for protocol/state logic.
• Provide typed Dart APIs (class, enum, Uint8List, ByteData) instead of pointer-style abstractions.

What is usable today

• Packet/header/control codecs (UdtPacket, UdtPacketHeader, UdtControlPacket, UdtHandshake).
• Core deterministic helpers (sequence numbers, timer model, IP helpers, MD5, loss/window/cache/buffer models).
• Congestion-control base/default deterministic behavior models.
• Networking compatibility planners/simulators (socket options, dual-stack, MTU, mobile constraints, transition simulation).
• Runtime planning/execution adapters including UdtSocketRuntimeApplier.applyProfile and UdtRawDatagramRuntimeTarget.

See detailed mapping in docs/migration.md and port status in TODO_PORT.md + docs/translation_status.md.

Install

dependencies:
  dart_udt: ^0.0.1-dev

Quickstart (pub-suitable, no real network I/O required)

Run:

dart run example/pub_quickstart.dart

This example demonstrates:

1. Building + parsing a control packet codec path.
2. Building a compatibility profile and runtime plan.
3. Running deterministic impairment simulation output.

Other examples

• Deterministic control codec only:
  • dart run example/control_packet_codec.dart
• Deterministic network impairment trace:
  • dart run example/network_simulation_trace.dart

Development

dart format .
dart analyze
dart test

Current limitations

• Full socket/session parity with upstream UDT is still in progress.
• Mixed local/system descriptor epoll parity is pending.
• Some live RawDatagramSocket option setters are best-effort and platform-limited by dart:io capabilities.

Documentation

• Migration guide: docs/migration.md
• Translation guardrail/status: docs/translation_status.md
• Trace-fixture corpus governance: docs/upstream_trace_fixture_corpus.md
• Port backlog and completion tracking: TODO_PORT.md