Make PrimitiveArray<T> support IReadOnlyList<T?>

apache · Nov 11, 2023 · 99715f2 · 99715f2
1 parent 3c99fbb
commit 99715f2
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Showing 2 changed files with 50 additions and 1 deletion.
diff --git a/csharp/src/Apache.Arrow/Arrays/PrimitiveArray.cs b/csharp/src/Apache.Arrow/Arrays/PrimitiveArray.cs
@@ -14,12 +14,13 @@
 // limitations under the License.
 
 using System;
+using System.Collections;
 using System.Collections.Generic;
 using System.Runtime.CompilerServices;
 
 namespace Apache.Arrow
 {
-    public abstract class PrimitiveArray<T> : Array
+    public abstract class PrimitiveArray<T> : Array, IReadOnlyList<T?>
         where T : struct
     {
         protected PrimitiveArray(ArrayData data)
@@ -66,5 +67,24 @@ protected PrimitiveArray(ArrayData data)
 
             return list;
         }
+
+        T? IReadOnlyList<T?>.this[int index] => GetValue(index);
+        int IReadOnlyCollection<T?>.Count => Length;
+
+        IEnumerator<T?> IEnumerable<T?>.GetEnumerator()
+        {
+            for (int index = 0; index < Length; index++)
+            {
+                yield return IsValid(index) ? Values[index] : null;
+            }
+        }
+
+        IEnumerator IEnumerable.GetEnumerator()
+        {
+            for (int index = 0; index < Length; index++)
+            {
+                yield return IsValid(index) ? Values[index] : null;
+            }
+        }
     }
 }
diff --git a/csharp/test/Apache.Arrow.Tests/ArrowArrayTests.cs b/csharp/test/Apache.Arrow.Tests/ArrowArrayTests.cs
@@ -14,6 +14,8 @@
 // limitations under the License.
 
 using System;
+using System.Collections;
+using System.Collections.Generic;
 using System.Numerics;
 using Xunit;
 
@@ -93,6 +95,33 @@ void TestIsValid(ArrowBuffer valueBuf, ArrowBuffer nullBitmapBuf, int length, in
             }
         }
 
+        [Fact]
+        public void EnumerateArray()
+        {
+            var array = new Int64Array.Builder().Append(1).Append(2).Build();
+
+            foreach(long? foo in (IEnumerable<long?>)array)
+            {
+                Assert.InRange(foo.Value, 1, 2);
+            }
+
+            foreach (object foo in (IEnumerable)array)
+            {
+                Assert.InRange((long)foo, 1, 2);
+            }
+        }
+
+        [Fact]
+        public void ArrayAsReadOnlyList()
+        {
+            Int64Array array = new Int64Array.Builder().Append(1).Append(2).Build();
+            var readOnlyList = (IReadOnlyList<long?>)array;
+
+            Assert.Equal(array.Length, readOnlyList.Count);
+            Assert.Equal(readOnlyList[0], 1);
+            Assert.Equal(readOnlyList[1], 2);
+        }
+
 #if NET5_0_OR_GREATER
         [Fact]
         public void SliceArray()