Fixed issues.

src/array/map/mod.rs

@@ -130,7 +130,7 @@ impl MapArray {
         &self.field
     }
 
-    /// Returns the element at index `i`
+    /// Returns the element at index `i`.
     #[inline]
     pub fn value(&self, i: usize) -> Box<dyn Array> {
         let offset = self.offsets[i];
@@ -143,7 +143,7 @@ impl MapArray {
         unsafe { self.field.slice_unchecked(offset.to_usize(), length) }
     }
 
-    /// Returns the element at index `i` as &str
+    /// Returns the element at index `i`.
     /// # Safety
     /// Assumes that the `i < self.len`.
     #[inline]

src/array/mod.rs

@@ -279,7 +279,7 @@ pub fn new_empty_array(data_type: DataType) -> Box<dyn Array> {
         FixedSizeList => Box::new(FixedSizeListArray::new_empty(data_type)),
         Struct => Box::new(StructArray::new_empty(data_type)),
         Union => Box::new(UnionArray::new_empty(data_type)),
-        Map => todo!(),
+        Map => Box::new(MapArray::new_empty(data_type)),
         Dictionary(key_type) => {
             with_match_physical_dictionary_key_type!(key_type, |$T| {
                 Box::new(DictionaryArray::<$T>::new_empty(data_type))
@@ -309,7 +309,7 @@ pub fn new_null_array(data_type: DataType, length: usize) -> Box<dyn Array> {
         FixedSizeList => Box::new(FixedSizeListArray::new_null(data_type, length)),
         Struct => Box::new(StructArray::new_null(data_type, length)),
         Union => Box::new(UnionArray::new_null(data_type, length)),
-        Map => todo!(),
+        Map => Box::new(MapArray::new_null(data_type, length)),
         Dictionary(key_type) => {
             with_match_physical_dictionary_key_type!(key_type, |$T| {
                 Box::new(DictionaryArray::<$T>::new_null(data_type, length))
@@ -347,7 +347,7 @@ pub fn clone(array: &dyn Array) -> Box<dyn Array> {
         FixedSizeList => clone_dyn!(array, FixedSizeListArray),
         Struct => clone_dyn!(array, StructArray),
         Union => clone_dyn!(array, UnionArray),
-        Map => todo!(),
+        Map => clone_dyn!(array, MapArray),
         Dictionary(key_type) => {
             with_match_physical_dictionary_key_type!(key_type, |$T| {
                 clone_dyn!(array, DictionaryArray::<$T>)

src/compute/aggregate/memory.rs

@@ -109,6 +109,10 @@ pub fn estimated_bytes_size(array: &dyn Array) -> usize {
         Dictionary(key_type) => with_match_physical_dictionary_key_type!(key_type, |$T| {
             dyn_dict!(array, $T)
         }),
-        Map => todo!(),
+        Map => {
+            let array = array.as_any().downcast_ref::<MapArray>().unwrap();
+            let offsets = array.offsets().len() * std::mem::size_of::<i32>();
+            offsets + estimated_bytes_size(array.field().as_ref()) + validity_size(array.validity())
+        }
     }
 }

src/io/json_integration/schema.rs

@@ -411,7 +411,7 @@ fn to_data_type(item: &Value, mut children: Vec<Field>) -> Result<DataType> {
             let sorted_keys = if let Some(Value::Bool(sorted_keys)) = item.get("keysSorted") {
                 *sorted_keys
             } else {
-                return Err(ArrowError::Schema("union requires mode".to_string()));
+                return Err(ArrowError::Schema("sorted keys not defined".to_string()));
             };
             DataType::Map(Box::new(children.pop().unwrap()), sorted_keys)
         }