yivo 2025.8.23.1

Message serialization

Yivo

Trying to standardize the way I access sensors.

Python

from yivo import Yivo, MsgInfo

# make some messages we want to send/receive
A = namedtuple("A","x y")      # id = 1
B = namedtuple("B", "x y z t") # id = 2

msgdb = MsgInfo()
msgdb[1] = ("2f", A) # 2 floats
msgdb[2] = ("4f", B) # 4 floats

yivo = Yivo(msgdb)
pkt = yivo.pack(1, A(1.,2.))

id = 0
while id == 0:
    b = serial_read() # get a byte from somewhere
    id = yivo.parse(b) # 0 or msg_id

err, msg = yivo.unpack() # err > 0 if failure to unpack

API

Part	In Checksum	Type	Description
Header		uint8_t[2]	default $K
Size	x	uint16_t	0-65,535 bytes, stored as [L,H] => `(H << 8)
Type	x	uint8_t	255 message IDs, 0 is not allowed as an ID
Data	x	uint8_t[Size]	payload data array
Checksum		uint8_t	XOR of size, type, and data bytes

0	1	2	3	4	...	-1
$	K	L	H	T	...	checksum

gentools

Generate messages for python and C/C++.

Type	Bytes	Format	Python	C/C++
uint8	1	B	int	uint8_t
uint16	2	H	int	uint16_t
uint32	4	I	int	uint32_t
uint64	8	Q	int	uint64_t
int8	1	b	int	int8_t
int16	2	h	int	int16_t
int32	4	i	int	int32_t
int64	8	q	int	int64_t
float	4	f	float	float
double	8	d	float	double

# comment ...
# comment ...

float     a # comment about var
uint8     b
int16[12] c

<enum something uint16_t
bob=0
tom=2
jerry=32
enum>

{
    "namespace": "foobar",
    "license": "MIT Kevin Walchko (c) 2023",
    "output": "test",
    "1": "messages/vec.yivo",
    "2": "messages/quat.yivo",
    "4": "messages/imu.yivo",
    "5": "messages/cal.yivo"
}

MIT License

Copyright (c) 2020 Mom's Friendly Robot Company

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.