Rafferty97 commented on code in PR #9418:
URL: https://github.com/apache/arrow-rs/pull/9418#discussion_r2928017509
##########
arrow-buffer/src/bigint/mod.rs:
##########
@@ -807,6 +807,46 @@ impl Shr<u8> for i256 {
}
}
+impl WrappingShl for i256 {
+ #[inline]
+ fn wrapping_shl(&self, rhs: u32) -> i256 {
+ (*self).shl(rhs)
Review Comment:
The dereference isn't necessary, and I think the wrapping behaviour should
be explicit rather than delegated to the `shl` implementation. i.e.:
```
impl WrappingShl for i256 {
fn wrapping_shl(&self, rhs: u32) -> Self {
// Truncating to a `u8` masks off the higher-order bits as required
self.shl(rhs as u8)
}
}
```
##########
arrow-buffer/src/bigint/mod.rs:
##########
@@ -807,6 +807,46 @@ impl Shr<u8> for i256 {
}
}
+impl WrappingShl for i256 {
+ #[inline]
+ fn wrapping_shl(&self, rhs: u32) -> i256 {
+ (*self).shl(rhs)
+ }
+}
+
+impl WrappingShr for i256 {
+ #[inline]
+ fn wrapping_shr(&self, rhs: u32) -> i256 {
+ (*self).shr(rhs)
+ }
+}
+
+// Define Shr<T> and Shl<T> for specified integer types
+macro_rules! define_wrapping_shift {
Review Comment:
I'm not sold on the idea of implementing `Shl`/`Shr` with wrapping
semantics, as this is inconsistent with the other built-in integer types, which
panic instead.
##########
arrow-buffer/src/bigint/mod.rs:
##########
@@ -807,6 +807,46 @@ impl Shr<u8> for i256 {
}
}
+impl WrappingShl for i256 {
+ #[inline]
+ fn wrapping_shl(&self, rhs: u32) -> i256 {
+ (*self).shl(rhs)
+ }
+}
+
+impl WrappingShr for i256 {
+ #[inline]
+ fn wrapping_shr(&self, rhs: u32) -> i256 {
Review Comment:
Similarly, I'd suggest:
```
impl WrappingShr for i256 {
fn wrapping_shr(&self, rhs: u32) -> Self {
// Truncating to a `u8` masks off the higher-order bits as required
self.shr(rhs as u8)
}
}
```
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