add slice_unchecked

src/array/fixed_size_list/iterator.rs

@@ -7,7 +7,7 @@ use super::FixedSizeListArray;
 
 impl IterableListArray for FixedSizeListArray {
     unsafe fn value_unchecked(&self, i: usize) -> Box<dyn Array> {
-        FixedSizeListArray::value(self, i)
+        FixedSizeListArray::value_unchecked(self, i)
     }
 }
 

src/array/fixed_size_list/mod.rs

@@ -103,12 +103,23 @@ impl FixedSizeListArray {
     }
 
     /// Returns the `Vec<T>` at position `i`.
+    /// # Panic:
+    /// panics iff `i >= self.len()`
     #[inline]
     pub fn value(&self, i: usize) -> Box<dyn Array> {
         self.values
             .slice(i * self.size as usize, self.size as usize)
     }
 
+    /// Returns the `Vec<T>` at position `i`.
+    /// # Safety:
+    /// Caller must ensure that `i < self.len()`
+    #[inline]
+    pub unsafe fn value_unchecked(&self, i: usize) -> Box<dyn Array> {
+        self.values
+            .slice_unchecked(i * self.size as usize, self.size as usize)
+    }
+
     /// Sets the validity bitmap on this [`FixedSizeListArray`].
     /// # Panic
     /// This function panics iff `validity.len() != self.len()`.

src/array/list/mod.rs

@@ -80,7 +80,10 @@ impl<O: Offset> ListArray<O> {
             let offset_1 = offsets[i + 1];
             let length = (offset_1 - offset).to_usize();
 
-            self.values.slice(offset.to_usize(), length)
+            // Safety:
+            // One of the invariants of the struct
+            // is that offsets are in bounds
+            unsafe { self.values.slice_unchecked(offset.to_usize(), length) }
         }
     }
 
@@ -93,7 +96,7 @@ impl<O: Offset> ListArray<O> {
         let offset_1 = *self.offsets.as_ptr().add(i + 1);
         let length = (offset_1 - offset).to_usize();
 
-        self.values.slice(offset.to_usize(), length)
+        self.values.slice_unchecked(offset.to_usize(), length)
     }
 
     /// Returns a slice of this [`ListArray`].