Fill pulse traces with NaN/-1 if data is too short

[philsmt]

When using the pulse separation feature in the AdqRawChannel component, currently an exception is thrown if the underlying train trace is too short for all pulses. This is not very useful however, as there's little way for users to fix that in any way, e.g. only get data for those pulses that fit, or reduce the pattern asked for.

Rather than throwing an exception, this PR instead fills the missing samples with NaN (for floating types, most likely) or -1 (in case of integer types, only with non-default settings). This maintains the information which data is missing, and the returned array can easily be truncated if desired.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 73.87%. Comparing base (049efdf) to head (8c63960).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #245   +/-   ##
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  Coverage   73.87%   73.87%           
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  Files          23       23           
  Lines        2989     2989           
=======================================
  Hits         2208     2208           
  Misses        781      781           

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[egorsobolev]

Looks it possible to make a bit simple:

Suggested change

	# The end of this pulse is beyond the trace length, try to
	# copy what remains and fill with placeholder as needed.
	if start < trace_len:
	# There is still some data to copy into this pulse.
	memcpy(&out[i, 0], &traces[j, start],
	(trace_len - start) * sizeof(traces[0, 0]))
	# Fill in the rest of this pulse with the placeholder value.
	for k in range(max(trace_len - start, 0), samples_per_pulse):
	out[i, k] = placeholder_val
	else:
	memcpy(&out[i, 0], &traces[j, start], bytes_per_pulse)
	# The end of this pulse is beyond the trace length, try to
	# copy what remains and fill with placeholder as needed.
	samples_to_copy = min(max(trace_len - start, 0), samples_per_pulse)
	# copy if data available
	memcpy(&out[i, 0], &traces[j, start], samples_to_copy * sizeof(traces[0, 0]))
	# Fill in the rest of this pulse with the placeholder value.
	for k in range(samples_to_copy, samples_per_pulse):
	out[i, k] = placeholder_val

[egorsobolev]

Suggested change

	end = start + samples_per_pulse
	if end > trace_len: