(arrow-rs) branch master updated: `unsafe` improvements (#6551)

[tustvold]

This is an automated email from the ASF dual-hosted git repository.

tustvold pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/arrow-rs.git


The following commit(s) were added to refs/heads/master by this push:
     new 04d0ebea7 `unsafe` improvements (#6551)
04d0ebea7 is described below

commit 04d0ebea717d3563a2065cb1469372f5211f6bb3
Author: Devin Jeanpierre <jeanpierr...@gmail.com>
AuthorDate: Mon Oct 21 00:55:27 2024 -0700

    `unsafe` improvements (#6551)
    
    * Remove unnecessary use of `unsafe` by reusing existing code
    
    * Remove unnecessary use of MaybeUninit
---
 arrow-buffer/src/builder/offset.rs | 7 +++++--
 arrow-buffer/src/util/bit_mask.rs  | 8 ++++----
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/arrow-buffer/src/builder/offset.rs 
b/arrow-buffer/src/builder/offset.rs
index 1ef0e3170..a51ca5f01 100644
--- a/arrow-buffer/src/builder/offset.rs
+++ b/arrow-buffer/src/builder/offset.rs
@@ -70,8 +70,11 @@ impl<O: ArrowNativeType> OffsetBufferBuilder<O> {
     ///
     /// Panics if offsets overflow `O`
     pub fn finish_cloned(&self) -> OffsetBuffer<O> {
-        O::from_usize(self.last_offset).expect("overflow");
-        unsafe { OffsetBuffer::new_unchecked(self.offsets.clone().into()) }
+        let cloned = Self {
+            offsets: self.offsets.clone(),
+            last_offset: self.last_offset,
+        };
+        cloned.finish()
     }
 }
 
diff --git a/arrow-buffer/src/util/bit_mask.rs 
b/arrow-buffer/src/util/bit_mask.rs
index d4c2fa474..83c395db8 100644
--- a/arrow-buffer/src/util/bit_mask.rs
+++ b/arrow-buffer/src/util/bit_mask.rs
@@ -127,16 +127,16 @@ unsafe fn set_upto_64bits(
 }
 
 /// # Safety
-/// The caller must ensure all arguments are within the valid range.
+/// The caller must ensure `data` has `offset..(offset + 8)` range, and `count 
<= 8`.
 #[inline]
 unsafe fn read_bytes_to_u64(data: &[u8], offset: usize, count: usize) -> u64 {
     debug_assert!(count <= 8);
-    let mut tmp = std::mem::MaybeUninit::<u64>::new(0);
+    let mut tmp: u64 = 0;
     let src = data.as_ptr().add(offset);
     unsafe {
-        std::ptr::copy_nonoverlapping(src, tmp.as_mut_ptr() as *mut u8, count);
-        tmp.assume_init()
+        std::ptr::copy_nonoverlapping(src, &mut tmp as *mut _ as *mut u8, 
count);
     }
+    tmp
 }
 
 /// # Safety