GH-45819: [C++] Add OptionalBitmapAnd utility#49848
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Shockp wants to merge 4 commits intoapache:mainfrom
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GH-45819: [C++] Add OptionalBitmapAnd utility#49848Shockp wants to merge 4 commits intoapache:mainfrom
Shockp wants to merge 4 commits intoapache:mainfrom
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Centralizes the logic for conjoining optional null bitmaps. Optimizes memory allocations by returning nullptr or falling back to CopyBitmap when one or both of the input buffers are missing.
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Rationale for this change
In Arrow, null bitmaps are optional and represented by
nullptrwhen a column contains no nulls. Previously, conjoining two optional bitmaps required downstream code to manually handle thenullptrchecks and memory allocations. This change centralizes that logic into a single, highly optimized utility function.What changes are included in this PR?
OptionalBitmapAndtocpp/src/arrow/util/bitmap_ops.handbitmap_ops.cc.nullptr: Returnsnullptr.nullptr: Returns a copy of the right buffer.nullptr: Returns a copy of the left buffer.BitmapAndfunction.Are these changes tested?
Yes. I added a new test case (
OptionalBitmapAnd) tocpp/src/arrow/util/bitmap_test.ccthat explicitly verifies the correct buffer allocation and bitwise output for all four memory states.Are there any user-facing changes?
No. This simply exposes a new C++ utility for internal development.
Closes #45819
OptionalBitmapAndutility #45819