Raw binary values

VILLASnode supports sending samples formated as raw binary data.

Signal values are encoded according to their configured data-type in either integer or IEEE-754 floating point values.

Implementation

The source code of the format-type is available here: https://git.rwth-aachen.de/acs/public/villas/node/-/blob/master/lib/formats/raw.cpp

Configuration

The Raw binary values format-type supports all generic format options plus the following:

bits (integer) = 32

The word size of each value in bits.

endianess (string: "little" | "big") = "little"

The endianess of multi-byte words.

The setting not be provided for bits = 8.

fake (boolean) = false

If enabled, the fake header mode VILLASnode uses the first three raw values in each en/decoded payload for the following purpose:

Sample field	Description	Data-type
sequence	Sequence number of the sample	integer
ts.origin.sec	Timestamp (in seconds) of sampling instant at origin	integer
ts.origin.nsec	Timestamp (nano-seconds fraction) of sampling instant at origin	integer

Example Configuration

nodes = {
        node = {
                type = "file"
                uri = "/dev/null"

                format = {
                        type = "raw"

                        bits = 32
                        endianess = "little"
                        fake = false
                }
        }
}

Notes

• Floating-point encoding is only supported for width larger or equal to 32 bit.
• The raw format-type does not support vectors. Only a single sample can be encoded per payload as there is no way to identify sample boundaries in the raw format.
• Complex sample values are supported and are encoded by real and imaginary parts with half of the precission as noted in the "Floating-point Precission" column above. E.g. in 64 bit mode real and imaginary components are encoded as two single-precission values encoded right after each other.
• Support for 128-bit wide values depends on you compiler support.