Add shared packages

src/Tribufu.Serialization/DecimalNullableStringConverter.cs

@@ -0,0 +1,46 @@
+// Copyright (c) Tribufu. All Rights Reserved.
+// SPDX-License-Identifier: MIT
+
+using Newtonsoft.Json;
+using System;
+using System.Globalization;
+
+namespace Tribufu.Serialization
+{
+    public class DecimalNullableStringConverter : JsonConverter<decimal?>
+    {
+        public override decimal? ReadJson(JsonReader reader, Type objectType, decimal? existingValue, bool hasExistingValue, JsonSerializer serializer)
+        {
+            if (reader.TokenType == JsonToken.Null)
+            {
+                return null;
+            }
+
+            if (reader.TokenType == JsonToken.String || reader.TokenType == JsonToken.Integer)
+            {
+                string value = reader.Value?.ToString();
+
+                if (string.IsNullOrWhiteSpace(value))
+                {
+                    return null;
+                }
+
+                return decimal.Parse(value);
+            }
+
+            throw new JsonSerializationException($"Unexpected token {reader.TokenType} when parsing decimal?.");
+        }
+
+        public override void WriteJson(JsonWriter writer, decimal? value, JsonSerializer serializer)
+        {
+            if (value.HasValue)
+            {
+                writer.WriteValue(value.Value.ToString(CultureInfo.InvariantCulture));
+            }
+            else
+            {
+                writer.WriteNull();
+            }
+        }
+    }
+}