hex-util-msg 0.0.1a2

HEXFELLOW Util Message

hex_util_msg

HEXFELLOW utility message library — a set of FlatBuffers message definitions and Python builder/parser helpers for robotics, teleoperation, and image transport.

Features

• Zero-copy deserialization via FlatBuffers for high-performance message passing
• Four message namespaces: msg_basic, msg_robot, msg_image, msg_teleop
• High-level builder API: build_* / parse_* function pairs that convert between bytes and plain Python dict / numpy objects
• NumPy integration: array fields are serialized and deserialized as numpy arrays

Installation

pip install hex_util_msg

Or install from source in editable mode:

git clone https://github.com/hexfellow/hex_util_msg.git
cd hex_util_msg
pip install -e .

Dependencies

Package	Version
flatbuffers	>= 25.0.0
numpy	>= 2.0.0

Quick Start

Basic Types

from hex_util_msg.builder_basic import (
    build_hex_float64, parse_hex_float64,
    build_hex_string, parse_hex_string,
    build_hex_float64_array, parse_hex_float64_array,
)

# Scalar
buf = build_hex_float64(ts_ns=1_000_000, data=3.14)
msg = parse_hex_float64(buf)
# msg == {"ts_ns": 1000000, "data": 3.14}

# String
buf = build_hex_string(ts_ns=1_000_000, data="hello")
msg = parse_hex_string(buf)
# msg == {"ts_ns": 1000000, "data": "hello"}

# Array
buf = build_hex_float64_array(ts_ns=1_000_000, data=[1.0, 2.0, 3.0])
msg = parse_hex_float64_array(buf)
# msg == {"ts_ns": 1000000, "data": array([1., 2., 3.])}

Robot Messages

import numpy as np
from hex_util_msg.builder_robot import (
    build_hex_arm_state, parse_hex_arm_state,
    build_hex_arm_ctrl, parse_hex_arm_ctrl,
)
from hex_util_msg.msg_robot import HexArmCtrlMode

# Build arm state
buf = build_hex_arm_state(
    ts_ns=123,
    jnt={"pos": [0.0, 0.25, 0.5], "vel": [0.0, 0.0, 0.0], "eff": None},
    pose={"px": 1.0, "py": 2.0, "pz": 3.0, "qx": 0.0, "qy": 0.0, "qz": 0.707, "qw": 0.707},
)
state = parse_hex_arm_state(buf)

# Build arm control
buf = build_hex_arm_ctrl(
    ts_ns=999,
    ctrl_mode=HexArmCtrlMode.mit,
    jnt={"pos": np.zeros(6), "vel": np.zeros(6), "eff": None},
    mit_tau=np.zeros(6),
    mit_kp=np.full(6, 100.0),
    mit_kd=np.full(6, 10.0),
)
ctrl = parse_hex_arm_ctrl(buf)

Image Messages

import numpy as np
from hex_util_msg.builder_image import build_hex_image_simple, parse_hex_image_simple
from hex_util_msg.msg_image import HexEncoding

frame = np.random.randint(0, 255, (480, 640, 3), dtype=np.uint8)
buf = build_hex_image_simple(
    ts_ns=1_704_000_000_000_000_000,
    encoding=HexEncoding.bgr8,
    width=640, height=480,
    data=frame,
)
msg = parse_hex_image_simple(buf)
# msg["data"] is a flat uint8 numpy array

Teleop Messages

from hex_util_msg.builder_teleop import (
    build_hex_teleop_joy, parse_hex_teleop_joy,
    build_hex_teleop_keyboard, parse_hex_teleop_keyboard,
)

# Joystick
buf = build_hex_teleop_joy(ts_ns=100, btn_a=True, axis_lx=0.5, axis_ly=-0.3)
joy = parse_hex_teleop_joy(buf)

# Keyboard
buf = build_hex_teleop_keyboard(ts_ns=200, key_w=True, key_a=True)
kb = parse_hex_teleop_keyboard(buf)

Message Namespaces

msg_basic — Scalar & Array Primitives

Every basic message carries a ts_ns timestamp and a data field.

Scalar types	Array types
HexBool	HexBoolArray
HexInt8 / HexUint8	HexInt8Array / HexUint8Array
HexInt16 / HexUint16	HexInt16Array / HexUint16Array
HexInt32 / HexUint32	HexInt32Array / HexUint32Array
HexInt64 / HexUint64	HexInt64Array / HexUint64Array
HexFloat32 / HexFloat64	HexFloat32Array / HexFloat64Array
HexString	HexStringArray

msg_robot — Robot State & Control

Message	Description
HexJnt	Joint data (pos/vel/eff arrays)
HexPose	7-DoF pose struct (px, py, pz, qx, qy, qz, qw)
HexArmState	Arm state with jnt + pose
HexArmCtrl	Arm control with ctrl_mode, jnt, pose, MIT/limit params
HexGripState	Gripper state with jnt
HexGripCtrl	Gripper control with ctrl_mode, jnt, force, MIT params
HexRgbCtrl	RGB LED control (r/g/b uint8 arrays)

Control modes (HexArmCtrlMode): mit, comp, pos, pose, pos_plan, pose_plan

Gripper modes (HexGripCtrlMode): mit, pos, force

msg_image — Image Transport

Message	Description
HexImageSimple	Image with encoding, dimensions, and raw byte data

Encodings (HexEncoding): bgr8, jpg, mono16, png

msg_teleop — Teleoperation Input

Message	Description
HexTeleopHello	Hello device with trigger, axes (x/y), buttons (w/x/y/z)
HexTeleopJoy	Joystick with 10 buttons, 6 axes, and hat
HexTeleopKeyboard	Keyboard with 26 key states (a–z)

Project Structure

hex_util_msg/
├── hex_util_msg/              # Python package
│   ├── __init__.py
│   ├── builder_basic.py       # build/parse for msg_basic
│   ├── builder_image.py       # build/parse for msg_image
│   ├── builder_robot.py       # build/parse for msg_robot
│   ├── builder_teleop.py      # build/parse for msg_teleop
│   ├── msg_basic/             # generated FlatBuffers code
│   ├── msg_image/             # generated FlatBuffers code
│   ├── msg_robot/             # generated FlatBuffers code
│   └── msg_teleop/            # generated FlatBuffers code
├── msgs/                      # FlatBuffers schema sources (.fbs)
│   ├── msg_basic/
│   ├── msg_image/
│   ├── msg_robot/
│   └── msg_teleop/
├── tests/                     # pytest test suite
├── generate.sh                # regenerate Python code from .fbs schemas
├── pyproject.toml
└── LICENSE

Regenerating Code from Schemas

If you modify .fbs files under msgs/, regenerate the Python bindings:

# Requires flatc (FlatBuffers compiler) on PATH
./generate.sh

This will remove existing generated directories and re-run flatc --python for all namespaces.

Testing

pip install pytest
pytest tests/ -v

License

Apache License 2.0 — see LICENSE for details.