common: Add hashing support for REE arrays

Author: brancz

datafusion/common/src/cast.rs

@@ -27,15 +27,16 @@ use arrow::array::{
     Int16Array, Int8Array, LargeBinaryArray, LargeListViewArray, LargeStringArray,
     ListViewArray, StringViewArray, UInt16Array,
 };
+use arrow::datatypes::RunEndIndexType;
 use arrow::{
     array::{
         Array, BinaryArray, BooleanArray, Date32Array, Date64Array, Decimal128Array,
         Decimal256Array, DictionaryArray, FixedSizeBinaryArray, FixedSizeListArray,
         Float32Array, Float64Array, GenericBinaryArray, GenericListArray,
         GenericStringArray, Int32Array, Int64Array, IntervalDayTimeArray,
         IntervalMonthDayNanoArray, IntervalYearMonthArray, LargeListArray, ListArray,
-        MapArray, NullArray, OffsetSizeTrait, PrimitiveArray, StringArray, StructArray,
-        Time32MillisecondArray, Time32SecondArray, Time64MicrosecondArray,
+        MapArray, NullArray, OffsetSizeTrait, PrimitiveArray, RunArray, StringArray,
+        StructArray, Time32MillisecondArray, Time32SecondArray, Time64MicrosecondArray,
         Time64NanosecondArray, TimestampMicrosecondArray, TimestampMillisecondArray,
         TimestampNanosecondArray, TimestampSecondArray, UInt32Array, UInt64Array,
         UInt8Array, UnionArray,
@@ -334,3 +335,8 @@ pub fn as_list_view_array(array: &dyn Array) -> Result<&ListViewArray> {
 pub fn as_large_list_view_array(array: &dyn Array) -> Result<&LargeListViewArray> {
     Ok(downcast_value!(array, LargeListViewArray))
 }
+
+// Downcast ArrayRef to RunArray
+pub fn as_run_array<R: RunEndIndexType>(array: &dyn Array) -> Result<&RunArray<R>> {
+    Ok(downcast_value!(array, RunArray, R))
+}