From 965433052afe75e54869cefd6d212aa8bd73e45f Mon Sep 17 00:00:00 2001
From: Raphael Taylor-Davies <1781103+tustvold@users.noreply.github.com>
Date: Wed, 22 Mar 2023 10:01:53 +0000
Subject: [PATCH] Return ScalarBuffer from PrimitiveArray::values (#3879)
 (#3896)

* Return ScalarBuffer from PrimitiveArray::values (#3879)

* Fix docs

* Review feedback
---
 arrow-array/src/array/primitive_array.rs |  4 +--
 arrow-buffer/src/buffer/scalar.rs        | 33 ++++++++++++++++++++++++
 arrow/src/lib.rs                         |  6 ++---
 3 files changed, 38 insertions(+), 5 deletions(-)

diff --git a/arrow-array/src/array/primitive_array.rs b/arrow-array/src/array/primitive_array.rs
index 78859bd5956f..241e2a051197 100644
--- a/arrow-array/src/array/primitive_array.rs
+++ b/arrow-array/src/array/primitive_array.rs
@@ -275,9 +275,9 @@ impl<T: ArrowPrimitiveType> PrimitiveArray<T> {
         self.data.is_empty()
     }
 
-    /// Returns a slice of the values of this array
+    /// Returns the values of this array
     #[inline]
-    pub fn values(&self) -> &[T::Native] {
+    pub fn values(&self) -> &ScalarBuffer<T::Native> {
         &self.raw_values
     }
 
diff --git a/arrow-buffer/src/buffer/scalar.rs b/arrow-buffer/src/buffer/scalar.rs
index 9b3a47785098..04c6d9dcc7ac 100644
--- a/arrow-buffer/src/buffer/scalar.rs
+++ b/arrow-buffer/src/buffer/scalar.rs
@@ -114,6 +114,39 @@ impl<T: ArrowNativeType> From<Vec<T>> for ScalarBuffer<T> {
     }
 }
 
+impl<'a, T: ArrowNativeType> IntoIterator for &'a ScalarBuffer<T> {
+    type Item = &'a T;
+    type IntoIter = std::slice::Iter<'a, T>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.as_ref().iter()
+    }
+}
+
+impl<T: ArrowNativeType, S: AsRef<[T]> + ?Sized> PartialEq<S> for ScalarBuffer<T> {
+    fn eq(&self, other: &S) -> bool {
+        self.as_ref().eq(other.as_ref())
+    }
+}
+
+impl<T: ArrowNativeType, const N: usize> PartialEq<ScalarBuffer<T>> for [T; N] {
+    fn eq(&self, other: &ScalarBuffer<T>) -> bool {
+        self.as_ref().eq(other.as_ref())
+    }
+}
+
+impl<T: ArrowNativeType> PartialEq<ScalarBuffer<T>> for [T] {
+    fn eq(&self, other: &ScalarBuffer<T>) -> bool {
+        self.as_ref().eq(other.as_ref())
+    }
+}
+
+impl<T: ArrowNativeType> PartialEq<ScalarBuffer<T>> for Vec<T> {
+    fn eq(&self, other: &ScalarBuffer<T>) -> bool {
+        self.as_slice().eq(other.as_ref())
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
diff --git a/arrow/src/lib.rs b/arrow/src/lib.rs
index 3d1bced298c9..4b1251ebcd2b 100644
--- a/arrow/src/lib.rs
+++ b/arrow/src/lib.rs
@@ -69,7 +69,7 @@
 //!
 //! let collected: Vec<_> = array.iter().collect();
 //! assert_eq!(collected, vec![Some(1), None, Some(3)]);
-//! assert_eq!(array.values(), [1, 0, 3])
+//! assert_eq!(array.values(), &[1, 0, 3])
 //! ```
 //!
 //! It is also possible to write generic code. For example, the following is generic over
@@ -168,7 +168,7 @@
 //!
 //! let array = parse_strings(["1", "2", "3"], DataType::Int32);
 //! let integers = array.as_any().downcast_ref::<Int32Array>().unwrap();
-//! assert_eq!(integers.values(), [1, 2, 3])
+//! assert_eq!(integers.values(), &[1, 2, 3])
 //! ```
 //!
 //! # Compute Kernels
@@ -192,7 +192,7 @@
 //!
 //! let array = parse_strings(["1", "2", "3"], &DataType::UInt32).unwrap();
 //! let integers = array.as_any().downcast_ref::<UInt32Array>().unwrap();
-//! assert_eq!(integers.values(), [1, 2, 3])
+//! assert_eq!(integers.values(), &[1, 2, 3])
 //! ```
 //!
 //! This module also implements many common vertical operations: