Writing File with only Meta Data

[tomritschel]

When trying to save a Waveform file with only metadata I get the following file:

dump.txt

Our use case is to write only the meta data using the RsWaveform library, as the data is directly written by another hardware module.
Things to notice:

• {LEVEL OFFS:inf,inf} tag is dumped, but was not set in code
• {DATE:2024-03-12;15:46:09} seems to be the one executed on saving the file, the given value in meta dictionary is not considered
• {EMPTYTAG-187:# tag is dumped, but was not set in code
• some zero bytes are written at the end of the file, though no data was given

[casabre]

Hi @tomritschel,

thanks for raising this issue. After quickly looking at the issue, I am seeing either some missing features in the saver or wrong expectations and the documentation and thus, it has to be improved.

{LEVEL OFFS:inf,inf} tag is dumped, but was not set in code

These values will be calculated out of the signal statistics and set afterwards. We can make this behavior optional.

{DATE:2024-03-12;15:46:09} seems to be the one executed on saving the file, the given value in meta dictionary is not considered

Probably, the meta data value was not considered and we can make this behavior optional

{EMPTYTAG-187:# tag is dumped, but was not set in code

That is a mandatory flag in order to work properly with the signal generator and will be set automatically.

some zero bytes are written at the end of the file, though no data was given

I am currently not aware and has to be investigated if it is an expected or erroneous behavior.