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src/Scanner/StellaOps.Scanner.WebService/Serialization/DeterministicCborSerializer.cs

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+using System.Collections.Generic;
+using System.Formats.Cbor;
+using System.Text;
+using System.Text.Json;
+
+namespace StellaOps.Scanner.WebService.Serialization;
+
+internal static class DeterministicCborSerializer
+{
+    private static readonly JsonSerializerOptions JsonOptions = new(JsonSerializerDefaults.Web)
+    {
+        WriteIndented = false
+    };
+
+    public static byte[] Serialize<T>(T value)
+    {
+        using var document = JsonSerializer.SerializeToDocument(value, JsonOptions);
+        var writer = new CborWriter(CborConformanceMode.Canonical);
+
+        WriteElement(writer, document.RootElement);
+        return writer.Encode();
+    }
+
+    private static void WriteElement(CborWriter writer, JsonElement element)
+    {
+        switch (element.ValueKind)
+        {
+            case JsonValueKind.Object:
+                WriteObject(writer, element);
+                return;
+            case JsonValueKind.Array:
+                writer.WriteStartArray(element.GetArrayLength());
+                foreach (var item in element.EnumerateArray())
+                {
+                    WriteElement(writer, item);
+                }
+                writer.WriteEndArray();
+                return;
+            case JsonValueKind.String:
+                writer.WriteTextString(element.GetString() ?? string.Empty);
+                return;
+            case JsonValueKind.Number:
+                if (element.TryGetInt64(out var int64))
+                {
+                    writer.WriteInt64(int64);
+                    return;
+                }
+
+                writer.WriteDouble(element.GetDouble());
+                return;
+            case JsonValueKind.True:
+                writer.WriteBoolean(true);
+                return;
+            case JsonValueKind.False:
+                writer.WriteBoolean(false);
+                return;
+            case JsonValueKind.Null:
+            case JsonValueKind.Undefined:
+                writer.WriteNull();
+                return;
+            default:
+                writer.WriteNull();
+                return;
+        }
+    }
+
+    private static void WriteObject(CborWriter writer, JsonElement element)
+    {
+        var properties = new List<(byte[] KeyBytes, string Key, JsonElement Value)>();
+
+        foreach (var property in element.EnumerateObject())
+        {
+            var keyBytes = Encoding.UTF8.GetBytes(property.Name);
+            properties.Add((keyBytes, property.Name, property.Value));
+        }
+
+        properties.Sort(static (left, right) =>
+        {
+            var lengthCompare = left.KeyBytes.Length.CompareTo(right.KeyBytes.Length);
+            if (lengthCompare != 0)
+            {
+                return lengthCompare;
+            }
+
+            for (var i = 0; i < left.KeyBytes.Length; i++)
+            {
+                var byteCompare = left.KeyBytes[i].CompareTo(right.KeyBytes[i]);
+                if (byteCompare != 0)
+                {
+                    return byteCompare;
+                }
+            }
+
+            return 0;
+        });
+
+        writer.WriteStartMap(properties.Count);
+
+        foreach (var (_, key, value) in properties)
+        {
+            writer.WriteTextString(key);
+            WriteElement(writer, value);
+        }
+
+        writer.WriteEndMap();
+    }
+}
+