[GitHub] [arrow-rs] viirya commented on a diff in pull request #2713: Add overflow-checking variants of arithmetic scalar dyn kernels

[GitBox <gi...@apache.org>]

viirya commented on code in PR #2713:
URL: https://github.com/apache/arrow-rs/pull/2713#discussion_r969908592


##########
arrow/src/compute/kernels/arithmetic.rs:
##########
@@ -834,12 +834,34 @@ where
 /// Add every value in an array by a scalar. If any value in the array is null then the
 /// result is also null. The given array must be a `PrimitiveArray` of the type same as
 /// the scalar, or a `DictionaryArray` of the value type same as the scalar.
+///
+/// This doesn't detect overflow. Once overflowing, the result will wrap around.
+/// For an overflow-checking variant, use `add_scalar_checked_dyn` instead.
 pub fn add_scalar_dyn<T>(array: &dyn Array, scalar: T::Native) -> Result<ArrayRef>
 where
     T: ArrowNumericType,
-    T::Native: Add<Output = T::Native>,
+    T::Native: ArrowNativeTypeOp,
 {
-    unary_dyn::<_, T>(array, |value| value + scalar)
+    unary_dyn::<_, T>(array, |value| value.add_wrapping(scalar))
+}
+
+/// Add every value in an array by a scalar. If any value in the array is null then the
+/// result is also null. The given array must be a `PrimitiveArray` of the type same as
+/// the scalar, or a `DictionaryArray` of the value type same as the scalar.
+///
+/// This detects overflow and returns an `Err` for that. For an non-overflow-checking variant,
+/// use `add_scalar_dyn` instead.
+pub fn add_scalar_checked_dyn<T>(array: &dyn Array, scalar: T::Native) -> Result<ArrayRef>

Review Comment:
   Yea, it will be much slower. As by default (ansi-mode disabled) in our case, non-checked kernels will be used. So most of time users will use faster one, except they have special need to use checked kernels.



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