Added an accessor for integer64

[brycepanza]

Closes #7618

Previously, the integer64 type was used using direct casts that lead to inconsistency, such as:

(const int64_t *)DATAPTR_RO(x) and (int64_t *)DATAPTR(x) or
(const int64_t *)REAL(x) and (int64_t *)REAL(x)

This was due to R not natively supporting 64-bit integer type, requiring its definition in the {bit64} pacakge. The direct casting leads to styling differences.

To fix this, we added an accessor for integer64 type in the src/data.table.h .

Now the datatype is accessible using INTEGER64_RO / INTEGER64 to cast to cast from the REAL_RO and REAL accessors.
We also submitted this in the {bit64} repository for future implementation, they will be looking into this after their next release #312.

Also, per this comment on our original issue we did not include new tests to inst/tests/test.Rraw, as our PR adds no new logic, as well as updated the NEWS.md file.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.04%. Comparing base (3a45206) to head (7e83f6e).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #7724   +/-   ##
=======================================
  Coverage   99.04%   99.04%           
=======================================
  Files          87       87           
  Lines       17123    17040   -83     
=======================================
- Hits        16959    16877   -82     
+ Misses        164      163    -1     

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[ben-schwen]

I guess there might have been some misunderstanding here.

Adding the definition from #7618 is not what the issue is about, but instead it should be about carefully iterating over every use of REAL(x) and REAL_RO(x) for integer64

[brycepanza]

@ben-schwen For clarification, this issue also requires replacing uses of REAL/_RO, DATAPTR/_RO, and direct casts on integer64 within the src directory as well to apply the accessor from this issue, or am I still misunderstanding? Thanks for the help!

[ben-schwen]

@ben-schwen For clarification, this issue also requires replacing uses of REAL/_RO, DATAPTR/_RO, and direct casts on integer64 within the src directory as well to apply the accessor from this issue, or am I still misunderstanding? Thanks for the help!

Exactly!