add benchmark

arrow-cast/Cargo.toml

@@ -76,3 +76,7 @@ harness = false
 [[bench]]
 name = "parse_decimal"
 harness = false
+
+[[bench]]
+name = "cast_dict_view"
+harness = false

arrow-cast/benches/cast_dict_view.rs

@@ -0,0 +1,59 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+use std::sync::Arc;
+
+use arrow_array::{types::UInt64Type, DictionaryArray, StringArray, UInt64Array};
+use arrow_cast::cast;
+use arrow_schema::DataType;
+use criterion::*;
+
+fn make_dict_array() -> DictionaryArray<UInt64Type> {
+    let values = StringArray::from_iter([
+        Some("small"),
+        Some("larger string more than 12 bytes"),
+        None,
+    ]);
+    let keys = UInt64Array::from_iter((0..10_000).map(|v| v % 3));
+
+    let dict = DictionaryArray::new(keys, Arc::new(values));
+    dict
+}
+
+fn criterion_benchmark(c: &mut Criterion) {
+    let dict = make_dict_array();
+    c.bench_function("dict to view", |b| {
+        b.iter(|| {
+            cast(&dict, &DataType::Utf8View).unwrap();
+        })
+    });
+
+    let view_array = cast(&dict, &DataType::Utf8View).unwrap();
+
+    c.bench_function("view to dict", |b| {
+        b.iter(|| {
+            cast(
+                &view_array,
+                &DataType::Dictionary(Box::new(DataType::UInt64), Box::new(DataType::Utf8)),
+            )
+            .unwrap();
+        })
+    });
+}
+
+criterion_group!(benches, criterion_benchmark);
+criterion_main!(benches);