From 8fa2f3ce261c5a951e7d48f52f8f35e6b3aa6474 Mon Sep 17 00:00:00 2001
From: Matthias Loibl <mail@matthiasloibl.com>
Date: Thu, 31 Oct 2024 16:53:31 +0000
Subject: [PATCH] arrow-cast: Support FixedSizeBinary packing

---
 arrow-cast/src/cast/dictionary.rs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arrow-cast/src/cast/dictionary.rs b/arrow-cast/src/cast/dictionary.rs
index ec0ab346f997..0a4d75c75ee0 100644
--- a/arrow-cast/src/cast/dictionary.rs
+++ b/arrow-cast/src/cast/dictionary.rs
@@ -325,6 +325,13 @@ pub(crate) fn cast_to_dictionary<K: ArrowDictionaryKeyType>(
             }
             pack_byte_to_dictionary::<K, GenericBinaryType<i64>>(array, cast_options)
         }
+        FixedSizeBinary(i32) => {
+            // If the input is a view type, we can avoid casting (thus copying) the data
+            if array.data_type() == &DataType::FixedSizeBinary(i32) {
+                return binary_view_to_dictionary::<K, i64>(array);
+            }
+            pack_byte_to_dictionary::<K, GenericBinaryType<i64>>(array, cast_options)
+        }
         _ => Err(ArrowError::CastError(format!(
             "Unsupported output type for dictionary packing: {dict_value_type:?}"
         ))),