CrystalZhou0529 opened a new pull request, #44822:
URL: https://github.com/apache/arrow/pull/44822
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### Rationale for this change
Use `CopyBitmap` to optimize performance in string casting from string-view
to offset string.
### What changes are included in this PR?
Originally, the way we create the bitmap is by appending one bit at a time,
which is slow. Since casting should not change the values in bitmap, this
feature takes advantage of `CopyBitmap` to create the entire bitmap at once.
Then, to create offsets and buffer array, I use `TypedBufferBuilder` as
suggested in the original comment
https://github.com/apache/arrow/pull/43302#discussion_r1686274741.
### Are these changes tested?
The original unit tests have passed.
### Are there any user-facing changes?
No, the casting behavior should remain unchanged.
closes [ #43573 ](https://github.com/apache/arrow/issues/43573)
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