Implement IComparable for Offset and Partition

Author: Олександр Ляхевич

src/Confluent.Kafka/Offset.cs

@@ -28,7 +28,7 @@ namespace Confluent.Kafka
     ///     its purpose is to add some syntactical sugar 
     ///     related to special values.
     /// </remarks>
-    public struct Offset : IEquatable<Offset>
+    public struct Offset : IEquatable<Offset>, IComparable<Offset>
     {
         private const long RD_KAFKA_OFFSET_BEGINNING = -2;
         private const long RD_KAFKA_OFFSET_END = -1;
@@ -287,5 +287,21 @@ public override string ToString()
                     return Value.ToString();
             }
         }
+
+        /// <summary>
+        /// Compares the current instance with another object of the same type and returns
+        /// an integer that indicates whether the current instance precedes, follows, or
+        /// occurs in the same position in the sort order as the other object.
+        /// </summary>
+        /// <param name="other">An object to compare with this instance.</param>
+        /// <returns>
+        /// A value that indicates the relative order of the objects being compared. The
+        /// return value has these meanings:
+        /// Value – Meaning
+        /// Less than zero – This instance precedes other in the sort order.
+        /// Zero – This instance occurs in the same position in the sort order as other.
+        /// Greater than zero – This instance follows other in the sort order.</returns>
+        public int CompareTo(Offset other)
+            => Value.CompareTo(other.Value);
     }
 }

src/Confluent.Kafka/Partition.cs

@@ -28,7 +28,7 @@ namespace Confluent.Kafka
     ///     its purpose is to add some syntactical sugar 
     ///     related to special values.
     /// </remarks>
-    public struct Partition : IEquatable<Partition>
+    public struct Partition : IEquatable<Partition>, IComparable<Partition>
     {
         private const int RD_KAFKA_PARTITION_UA = -1;
 
@@ -224,5 +224,21 @@ public override string ToString()
                     return $"[{Value}]";
             }
         }
+
+        /// <summary>
+        /// Compares the current instance with another object of the same type and returns
+        /// an integer that indicates whether the current instance precedes, follows, or
+        /// occurs in the same position in the sort order as the other object.
+        /// </summary>
+        /// <param name="other">An object to compare with this instance.</param>
+        /// <returns>
+        /// A value that indicates the relative order of the objects being compared. The
+        /// return value has these meanings:
+        /// Value – Meaning
+        /// Less than zero – This instance precedes other in the sort order.
+        /// Zero – This instance occurs in the same position in the sort order as other.
+        /// Greater than zero – This instance follows other in the sort order.</returns>
+        public int CompareTo(Partition other)
+            => Value.CompareTo(other.Value);
     }
 }

test/Confluent.Kafka.UnitTests/Offset.cs

@@ -69,6 +69,17 @@ public void Inequality()
             Assert.True(a >= a2);
         }
 
+        [Fact]
+        public void CompareTo()
+        {
+            Offset a = new Offset(42);
+            Offset a2 = new Offset(42);
+            Offset b = new Offset(37);
+            Assert.True(a.CompareTo(b) > 0);
+            Assert.True(b.CompareTo(a) < 0);
+            Assert.True(a.CompareTo(a2) == 0);
+        }
+
         [Fact]
         public void Addition_Int()
         {

test/Confluent.Kafka.UnitTests/Partition.cs

@@ -66,6 +66,17 @@ public void Inequality()
             Assert.True(a >= a2);
         }
 
+        [Fact]
+        public void CompareTo()
+        {
+            Partition a = new Partition(42);
+            Partition a2 = new Partition(42);
+            Partition b = new Partition(37);
+            Assert.True(a.CompareTo(b) > 0);
+            Assert.True(b.CompareTo(a) < 0);
+            Assert.True(a.CompareTo(a2) == 0);
+        }
+
         [Fact]
         public void Hash()
         {