minor: refactor array reverse internals #18445
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Jefffrey
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Nov 2, 2025
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| fn general_array_reverse<O: OffsetSizeTrait + TryFrom<i64>>( | ||
| fn general_array_reverse<O: OffsetSizeTrait>( |
| OffsetBuffer::<O>::new(offsets.into()), | ||
| arrow::array::make_array(data), | ||
| Some(nulls.into()), | ||
| array.nulls().cloned(), |
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We can directly copy the nulls from the input array instead of recreating it step by step (do the same for fixed size lists below)
| MutableArrayData::with_capacities(vec![&original_data], false, capacity); | ||
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| for (row_index, offset_window) in array.offsets().windows(2).enumerate() { | ||
| for (row_index, (&start, &end)) in array.offsets().iter().tuple_windows().enumerate() |
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Using tuple_windows from itertools for a nicer interface on grabbing the start & end indices
| nulls.push(false); | ||
| offsets.push(offsets[row_index] + O::one()); | ||
| mutable.extend(0, 0, 1); | ||
| offsets.push(offsets[row_index]); |
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We can just have an empty list here since it's null anyway, instead of extending the child array by one element
| let end = offset_window[1]; | ||
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| let mut index = end - O::one(); | ||
| let mut cnt = 0; |
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cnt can be determined once up front
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Nice! |
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Which issue does this PR close?
N/A
Rationale for this change
When reviewing #18424 I noticed some refactoring that could be applied to existing array reverse implementation.
What changes are included in this PR?
Are these changes tested?
See my comments for the refactors & justifications.
Existing tests.
Are there any user-facing changes?
No.