Add regex_program class for use with all regex APIs

[davidwendt]

Description

Adds a new regex_program class to encapsulate a regex pattern and parameters used for executing regex calls on strings columns in libcudf. This provides a single object to hold the regex settings rather than adding or updating parameters to every call. Given a pattern (and other settings), it will compile and validate the pattern and build the set of instructions/commands needed to execute the regex on a strings column. Converting the pattern is done in CPU code. The object contains no state data and can be reused on the same API or other similar calls as appropriate (per the settings).
The object can also be queried to help with resource allocation/expectations.

The main files to review are the new regex_program* source files plus the corresponding changes in regexec.cpp (renamed from .cu). The remainder are simply side-effects and have common patterns to use the new object.
No function or behavior has changed but rather an new interface has been added over existing function but additional tests have been added to exercise through the companion APIs.

Currently, all regex APIs are duplicated -- the original API plus a new one accepting a regex_progam object. Once accepted we may consider deprecating the non-object APIs and then removing them in a future release.

This will help with changes needed for #10852

Checklist

• I am familiar with the Contributing Guidelines.
• New or existing tests cover these changes.
• The documentation is up to date with these changes.

[codecov]

Codecov Report

Base: 87.47% // Head: 88.07% // Increases project coverage by +0.59% 🎉

Coverage data is based on head (d2d997a) compared to base (f817d96).
Patch has no changes to coverable lines.

Additional details and impacted files

@@               Coverage Diff                @@
##           branch-22.12   #11927      +/-   ##
================================================
+ Coverage         87.47%   88.07%   +0.59%     
================================================
  Files               133      135       +2     
  Lines             21826    22025     +199     
================================================
+ Hits              19093    19398     +305     
+ Misses             2733     2627     -106     

Impacted Files	Coverage Δ
python/cudf/cudf/core/column/interval.py	85.45% <0.00%> (-9.10%)	⬇️
python/cudf/cudf/io/text.py	91.66% <0.00%> (-8.34%)	⬇️
python/cudf/cudf/core/_base_index.py	81.28% <0.00%> (-4.27%)	⬇️
python/cudf/cudf/io/json.py	92.06% <0.00%> (-2.68%)	⬇️
python/cudf/cudf/utils/utils.py	89.91% <0.00%> (-0.69%)	⬇️
python/cudf/cudf/core/column/timedelta.py	90.17% <0.00%> (-0.58%)	⬇️
python/cudf/cudf/core/column/datetime.py	89.21% <0.00%> (-0.51%)	⬇️
python/cudf/cudf/core/column/column.py	87.96% <0.00%> (-0.46%)	⬇️
python/dask_cudf/dask_cudf/core.py	73.72% <0.00%> (-0.41%)	⬇️
python/cudf/cudf/io/parquet.py	90.45% <0.00%> (-0.39%)	⬇️
... and 39 more

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[vyasr]

I like the refactor. I mostly have questions about the current encapsulation of the program impl class.

Also, should we be concerned about overloading the "prog" name given that we already use this on device for the reprog_device class? Are the two similar enough that it makes sense to have similar names? Should we consider an alternative?

[vyasr]

We may want to include a note in the developer guide about our preferred uses of forward declarations of includes (if you can come up with a pithy summary).

[vyasr]

LGTM

[bdice]

Looks great! Encapsulating information in the regex_program will help keep the public APIs constrained while adding new features that can be controlled via the program.

[davidwendt]

@gpucibot merge

[jlowe]

FYI, surprisingly this PR has broken a large number of RAPIDS Accelerator tests related to regex. Tests pass before this change and fail afterwards. In at least one of the tests, the nature of the failure appears to be solely related to the data column. There are null characters (or uninitialized memory?) appearing in blocks of rows periodically in the output. I'll try to narrow this down to a repro case in C++.

[davidwendt]

I just noticed this too. I'm working on a fix.