Added support to read binary dict encoded from parquet (#781)

src/io/parquet/read/binary/dictionary.rs

@@ -9,7 +9,9 @@ use parquet2::{
 
 use super::super::utils as other_utils;
 use crate::{
-    array::{Array, DictionaryArray, DictionaryKey, Offset, PrimitiveArray, Utf8Array},
+    array::{
+        Array, BinaryArray, DictionaryArray, DictionaryKey, Offset, PrimitiveArray, Utf8Array,
+    },
     bitmap::{utils::BitmapIter, MutableBitmap},
     datatypes::DataType,
     error::{ArrowError, Result},
@@ -156,11 +158,21 @@ where
     };
     let keys = PrimitiveArray::from_data(K::PRIMITIVE.into(), indices.into(), validity.into());
     let data_type = DictionaryArray::<K>::get_child(&data_type).clone();
-    let values = Arc::new(Utf8Array::from_data(
-        data_type,
-        offsets.into(),
-        values.into(),
-        None,
-    ));
+    use crate::datatypes::PhysicalType::*;
+    let values = match data_type.to_physical_type() {
+        Binary | LargeBinary => Arc::new(BinaryArray::from_data(
+            data_type,
+            offsets.into(),
+            values.into(),
+            None,
+        )) as Arc<dyn Array>,
+        Utf8 | LargeUtf8 => Arc::new(Utf8Array::from_data(
+            data_type,
+            offsets.into(),
+            values.into(),
+            None,
+        )),
+        _ => unreachable!(),
+    };
     Ok(Box::new(DictionaryArray::<K>::from_data(keys, values)))
 }

src/io/parquet/read/mod.rs

@@ -196,8 +196,10 @@ fn dict_read<
         Float64 => {
             primitive::iter_to_dict_array::<K, _, _, _, _, _>(iter, metadata, data_type, |x: f64| x)
         }
-        Utf8 => binary::iter_to_dict_array::<K, i32, _, _>(iter, metadata, data_type),
-        LargeUtf8 => binary::iter_to_dict_array::<K, i64, _, _>(iter, metadata, data_type),
+        Utf8 | Binary => binary::iter_to_dict_array::<K, i32, _, _>(iter, metadata, data_type),
+        LargeUtf8 | LargeBinary => {
+            binary::iter_to_dict_array::<K, i64, _, _>(iter, metadata, data_type)
+        }
         other => Err(ArrowError::NotYetImplemented(format!(
             "Reading dictionaries of type {:?}",
             other

tests/it/io/parquet/mod.rs

@@ -719,17 +719,22 @@ fn arrow_type() -> Result<()> {
 
     let indices = PrimitiveArray::from_values((0..3u64).map(|x| x % 2));
     let values = PrimitiveArray::from_slice([1.0f32, 3.0]);
-    let array3 = DictionaryArray::from_data(indices, std::sync::Arc::new(values));
+    let array3 = DictionaryArray::from_data(indices.clone(), std::sync::Arc::new(values));
+
+    let values = BinaryArray::<i32>::from_slice([b"ab", b"ac"]);
+    let array4 = DictionaryArray::from_data(indices, std::sync::Arc::new(values));
 
     let schema = Schema::from(vec![
         Field::new("a1", dt1, true),
         Field::new("a2", array2.data_type().clone(), true),
         Field::new("a3", array3.data_type().clone(), true),
+        Field::new("a4", array4.data_type().clone(), true),
     ]);
     let batch = Chunk::try_new(vec![
         Arc::new(array) as Arc<dyn Array>,
         Arc::new(array2),
         Arc::new(array3),
+        Arc::new(array4),
     ])?;
 
     let r = integration_write(&schema, &[batch.clone()])?;