Digital waveform .wfm metadata helpers.
TekHSI populates digital_bitmask from WaveformHeader.bitmask (bit n set
means digital line n is present in the packed byte stream). The standard WFM
tekmeta block does not define a dedicated bitmask field, but it does carry
d0-d7 digital-probe state keys. We persist the integer bitmask in
tekmeta extended_metadata under digital_bitmask and mirror active lines
into digital_probe_*_state for scope/ref compatibility.
read_digital_wfm(path: str) -> DigitalWaveform | FastFrameDigitalWaveform
Load a digital waveform and restore digital_bitmask from tekmeta.
restore_digital_bitmask_from_meta(waveform: DigitalWaveform | FastFrameDigitalWaveform) -> int
Restore digital_bitmask on a waveform after read_file().
stamp_digital_bitmask_meta(waveform: DigitalWaveform | FastFrameDigitalWaveform) -> None
Write digital_bitmask into WFM tekmeta before write_file().
write_digital_wfm(path: str, waveform: DigitalWaveform | FastFrameDigitalWaveform) -> None
Save a digital waveform, preserving digital_bitmask in tekmeta.