Add support for BinaryView in arrow_string::length (#6359)

* Add support for BinaryView in arrow_string::length

* Adding a longer binary value to binary view test.

arrow-string/src/length.rs

@@ -93,6 +93,14 @@ pub fn length(array: &dyn Array) -> Result<ArrayRef, ArrowError> {
  DataType::FixedSizeBinary(len) | DataType::FixedSizeList(_, len) => Ok(Arc::new(
  Int32Array::new(vec![*len; array.len()].into(), array.nulls().cloned()),
  )),
+ DataType::BinaryView => {
+ let list = array.as_binary_view();
+ let v = list.views().iter().map(|v| *v as i32).collect::<Vec<_>>();
+ Ok(Arc::new(PrimitiveArray::<Int32Type>::new(
+ v.into(),
+ list.nulls().cloned(),
+ )))
+ }
  other => Err(ArrowError::ComputeError(format!(
  "length not supported for {other:?}"
  ))),
@@ -253,6 +261,23 @@ mod tests {
  length_binary_helper!(i64, Int64Array, length, value, result)
  }
 
+ #[test]
+ fn length_test_binary_view() {
+ let value: Vec<&[u8]> = vec![
+ b"zero",
+ &[0xff, 0xf8],
+ b"two",
+ b"this is a longer string to test binary array with",
+ ];
+ let expected: Vec<i32> = vec![4, 2, 3, 49];
+
+ let array = BinaryViewArray::from(value);
+ let result = length(&array).unwrap();
+ let result = result.as_any().downcast_ref::<Int32Array>().unwrap();
+ let expected: Int32Array = expected.into();
+ assert_eq!(&expected, result);
+ }
+
  #[test]
  fn length_test_list() {
  let value = vec![