Add casting operators for int? and long? (#35)

+semver: feature

Author: Carlos

Diff for: BencodeNET.Tests/Objects/BNumberTests.cs

@@ -159,6 +159,102 @@ public void ToString_WithFormat_SameAsLong()
             str1.Should().Be(str2);
         }
 
+        [Fact]
+        public void CanCastFromInt()
+        {
+            int number = 12345;
+            var bnumber = (BNumber)number;
+            bnumber.Should().Be(12345);
+        }
+
+        [Fact]
+        public void CanCastFromLong()
+        {
+            long number = 12345;
+            var bnumber = (BNumber)number;
+            bnumber.Should().Be(12345);
+        }
+
+        [Fact]
+        public void CanCastFromNullableInt_WhenNull()
+        {
+            int? number = null;
+            var bnumber = (BNumber)number;
+            bnumber.Should().BeNull();
+        }
+
+        [Fact]
+        public void CanCastFromNullableLong_WhenNull()
+        {
+            long? number = null;
+            var bnumber = (BNumber)number;
+            bnumber.Should().BeNull();
+        }
+
+        [Fact]
+        public void CanCastFromNullableInt_WhenNotNull()
+        {
+            int? number = 12345;
+            var bnumber = (BNumber)number;
+            bnumber.Should().Be(12345);
+        }
+
+        [Fact]
+        public void CanCastFromNullableLong_WhenNotNull()
+        {
+            long? number = 12345;
+            var bnumber = (BNumber)number;
+            bnumber.Should().Be(12345);
+        }
+
+        [Fact]
+        public void CanCastToInt()
+        {
+            BNumber bnumber = new BNumber(12345);
+            int number = (int)bnumber;
+            number.Should().Be(12345);
+        }
+
+        [Fact]
+        public void CanCastToLong()
+        {
+            BNumber bnumber = new BNumber(12345);
+            long number = (long)bnumber;
+            number.Should().Be(12345);
+        }
+
+        [Fact]
+        public void CanCastToNullableInt_WhenNull()
+        {
+            BNumber bnumber = null;
+            var number = (int?)bnumber;
+            number.Should().BeNull();
+        }
+
+        [Fact]
+        public void CanCastToNullableLong_WhenNull()
+        {
+            BNumber bnumber = null;
+            var number = (long?)bnumber;
+            number.Should().BeNull();
+        }
+
+        [Fact]
+        public void CanCastToNullableInt_WhenNotNull()
+        {
+            BNumber bnumber = 12345;
+            var number = (int?)bnumber;
+            number.Should().Be(12345);
+        }
+
+        [Fact]
+        public void CanCastToNullableLong_WhenNotNull()
+        {
+            BNumber bnumber = 12345;
+            var number = (long?)bnumber;
+            number.Should().Be(12345);
+        }
+
         [Fact]
         public void CanCastFromDateTime()
         {

Diff for: BencodeNET/Objects/BNumber.cs

@@ -49,6 +49,18 @@ protected override void EncodeObject(BencodeStream stream)
             stream.Write(Value);
             stream.Write('e');
         }
+        
+        public static implicit operator int?(BNumber bint)
+        {
+            if (bint == null) return null;
+            return (int)bint.Value;
+        }
+
+        public static implicit operator long?(BNumber bint)
+        {
+            if (bint == null) return null;
+            return bint.Value;
+        }
 
         public static implicit operator int(BNumber bint)
         {