Working json canonicalisation dev/e2ee{canonical-json}

4 files changed, 328 insertions, 23 deletions

diff --git a/LibMatrix.sln b/LibMatrix.sln
index c068216..3294f77 100644
--- a/LibMatrix.sln
+++ b/LibMatrix.sln
@@ -5,22 +5,14 @@ VisualStudioVersion = 17.0.31903.59
 MinimumVisualStudioVersion = 10.0.40219.1

 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "LibMatrix", "LibMatrix\LibMatrix.csproj", "{2A07D7DA-7B8F-432D-8AD3-9679B58A7C19}"

 EndProject

-Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "ExampleBots", "ExampleBots", "{840309F0-435B-43A7-8471-8C2BE643889D}"

-EndProject

 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Utilities", "Utilities", "{A6345ECE-4C5E-400F-9130-886E343BF314}"

 EndProject

 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "LibMatrix.MxApiExtensions", "LibMatrix.MxApiExtensions\LibMatrix.MxApiExtensions.csproj", "{32D9616B-91BB-4B43-97C6-2C3840C12EA6}"

 EndProject

-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "LibMatrix.ExampleBot", "ExampleBots\LibMatrix.ExampleBot\LibMatrix.ExampleBot.csproj", "{1B1B2197-61FB-416F-B6C8-845F2E5A0442}"

-EndProject

-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ModerationBot", "ExampleBots\ModerationBot\ModerationBot.csproj", "{8F0A820E-F6AE-45A2-970E-7A3759693919}"

-EndProject

 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "LibMatrix.DebugDataValidationApi", "Utilities\LibMatrix.DebugDataValidationApi\LibMatrix.DebugDataValidationApi.csproj", "{35DF9A1A-D988-4225-AFA3-06BB8EDEB559}"

 EndProject

 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "LibMatrix.Utilities.Bot", "Utilities\LibMatrix.Utilities.Bot\LibMatrix.Utilities.Bot.csproj", "{3ACF2613-E23F-42C2-925E-0BB4FC3AB1F7}"

 EndProject

-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "PluralContactBotPoC", "ExampleBots\PluralContactBotPoC\PluralContactBotPoC.csproj", "{FB8FE4EB-B53B-464B-A5FD-9BF9D0F3EF9B}"

-EndProject

 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Tests", "Tests", "{BFE16D8E-EFC5-49F6-9854-DB001309B3B4}"

 EndProject

 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "LibMatrix.Tests", "Tests\LibMatrix.Tests\LibMatrix.Tests.csproj", "{345934FF-CA81-4A4B-B137-9F198102C65F}"

@@ -37,6 +29,24 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "LibMatrix.EventTypes", "Lib
 EndProject

 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "LibMatrix.HomeserverEmulator", "Tests\LibMatrix.HomeserverEmulator\LibMatrix.HomeserverEmulator.csproj", "{D44DB78D-9BAD-4AB6-A054-839ECA9D68D2}"

 EndProject

+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ArcaneLibs.Blazor.Components", "ArcaneLibs\ArcaneLibs.Blazor.Components\ArcaneLibs.Blazor.Components.csproj", "{ABAB8F42-A4BC-4ABF-AF1D-FDB40D87A91C}"

+EndProject

+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ArcaneLibs.Legacy", "ArcaneLibs\ArcaneLibs.Legacy\ArcaneLibs.Legacy.csproj", "{F94D35FF-E90E-4B86-B26E-A8E46EB54BDD}"

+EndProject

+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ArcaneLibs.Logging", "ArcaneLibs\ArcaneLibs.Logging\ArcaneLibs.Logging.csproj", "{711D1579-9228-47BA-9CB3-C237F7E8F403}"

+EndProject

+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ArcaneLibs.StringNormalisation", "ArcaneLibs\ArcaneLibs.StringNormalisation\ArcaneLibs.StringNormalisation.csproj", "{87270607-F95C-4EED-AE69-57666863EFDF}"

+EndProject

+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ArcaneLibs.Timings", "ArcaneLibs\ArcaneLibs.Timings\ArcaneLibs.Timings.csproj", "{5EE6E02C-A63F-4864-91F3-7375B4C50189}"

+EndProject

+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ArcaneLibs.UsageTest", "ArcaneLibs\ArcaneLibs.UsageTest\ArcaneLibs.UsageTest.csproj", "{7E7BBBDD-CE09-4298-B839-5EBDCA5D0DAF}"

+EndProject

+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ArcaneLib.Tests", "ArcaneLibs\ArcaneLib.Tests\ArcaneLib.Tests.csproj", "{E6BF8A7E-92F6-4761-A793-1EC709F7E2BF}"

+EndProject

+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "LibMatrix.DevTestBot", "Utilities\LibMatrix.DevTestBot\LibMatrix.DevTestBot.csproj", "{6F4A4ABC-5E42-4293-80E6-0C38FE8C9EC5}"

+EndProject

+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "LibMatrix.E2eeTestKit", "Utilities\LibMatrix.E2eeTestKit\LibMatrix.E2eeTestKit.csproj", "{A1066F8F-CE8A-4F60-9EFB-553C9E794435}"

+EndProject

 Global

 	GlobalSection(SolutionConfigurationPlatforms) = preSolution

 		Debug|Any CPU = Debug|Any CPU

@@ -54,14 +64,6 @@ Global
 		{32D9616B-91BB-4B43-97C6-2C3840C12EA6}.Debug|Any CPU.Build.0 = Debug|Any CPU

 		{32D9616B-91BB-4B43-97C6-2C3840C12EA6}.Release|Any CPU.ActiveCfg = Release|Any CPU

 		{32D9616B-91BB-4B43-97C6-2C3840C12EA6}.Release|Any CPU.Build.0 = Release|Any CPU

-		{1B1B2197-61FB-416F-B6C8-845F2E5A0442}.Debug|Any CPU.ActiveCfg = Debug|Any CPU

-		{1B1B2197-61FB-416F-B6C8-845F2E5A0442}.Debug|Any CPU.Build.0 = Debug|Any CPU

-		{1B1B2197-61FB-416F-B6C8-845F2E5A0442}.Release|Any CPU.ActiveCfg = Release|Any CPU

-		{1B1B2197-61FB-416F-B6C8-845F2E5A0442}.Release|Any CPU.Build.0 = Release|Any CPU

-		{8F0A820E-F6AE-45A2-970E-7A3759693919}.Debug|Any CPU.ActiveCfg = Debug|Any CPU

-		{8F0A820E-F6AE-45A2-970E-7A3759693919}.Debug|Any CPU.Build.0 = Debug|Any CPU

-		{8F0A820E-F6AE-45A2-970E-7A3759693919}.Release|Any CPU.ActiveCfg = Release|Any CPU

-		{8F0A820E-F6AE-45A2-970E-7A3759693919}.Release|Any CPU.Build.0 = Release|Any CPU

 		{35DF9A1A-D988-4225-AFA3-06BB8EDEB559}.Debug|Any CPU.ActiveCfg = Debug|Any CPU

 		{35DF9A1A-D988-4225-AFA3-06BB8EDEB559}.Debug|Any CPU.Build.0 = Debug|Any CPU

 		{35DF9A1A-D988-4225-AFA3-06BB8EDEB559}.Release|Any CPU.ActiveCfg = Release|Any CPU

@@ -70,10 +72,6 @@ Global
 		{3ACF2613-E23F-42C2-925E-0BB4FC3AB1F7}.Debug|Any CPU.Build.0 = Debug|Any CPU

 		{3ACF2613-E23F-42C2-925E-0BB4FC3AB1F7}.Release|Any CPU.ActiveCfg = Release|Any CPU

 		{3ACF2613-E23F-42C2-925E-0BB4FC3AB1F7}.Release|Any CPU.Build.0 = Release|Any CPU

-		{FB8FE4EB-B53B-464B-A5FD-9BF9D0F3EF9B}.Debug|Any CPU.ActiveCfg = Debug|Any CPU

-		{FB8FE4EB-B53B-464B-A5FD-9BF9D0F3EF9B}.Debug|Any CPU.Build.0 = Debug|Any CPU

-		{FB8FE4EB-B53B-464B-A5FD-9BF9D0F3EF9B}.Release|Any CPU.ActiveCfg = Release|Any CPU

-		{FB8FE4EB-B53B-464B-A5FD-9BF9D0F3EF9B}.Release|Any CPU.Build.0 = Release|Any CPU

 		{345934FF-CA81-4A4B-B137-9F198102C65F}.Debug|Any CPU.ActiveCfg = Debug|Any CPU

 		{345934FF-CA81-4A4B-B137-9F198102C65F}.Debug|Any CPU.Build.0 = Debug|Any CPU

 		{345934FF-CA81-4A4B-B137-9F198102C65F}.Release|Any CPU.ActiveCfg = Release|Any CPU

@@ -98,17 +96,59 @@ Global
 		{D44DB78D-9BAD-4AB6-A054-839ECA9D68D2}.Debug|Any CPU.Build.0 = Debug|Any CPU

 		{D44DB78D-9BAD-4AB6-A054-839ECA9D68D2}.Release|Any CPU.ActiveCfg = Release|Any CPU

 		{D44DB78D-9BAD-4AB6-A054-839ECA9D68D2}.Release|Any CPU.Build.0 = Release|Any CPU

+		{ABAB8F42-A4BC-4ABF-AF1D-FDB40D87A91C}.Debug|Any CPU.ActiveCfg = Debug|Any CPU

+		{ABAB8F42-A4BC-4ABF-AF1D-FDB40D87A91C}.Debug|Any CPU.Build.0 = Debug|Any CPU

+		{ABAB8F42-A4BC-4ABF-AF1D-FDB40D87A91C}.Release|Any CPU.ActiveCfg = Release|Any CPU

+		{ABAB8F42-A4BC-4ABF-AF1D-FDB40D87A91C}.Release|Any CPU.Build.0 = Release|Any CPU

+		{F94D35FF-E90E-4B86-B26E-A8E46EB54BDD}.Debug|Any CPU.ActiveCfg = Debug|Any CPU

+		{F94D35FF-E90E-4B86-B26E-A8E46EB54BDD}.Debug|Any CPU.Build.0 = Debug|Any CPU

+		{F94D35FF-E90E-4B86-B26E-A8E46EB54BDD}.Release|Any CPU.ActiveCfg = Release|Any CPU

+		{F94D35FF-E90E-4B86-B26E-A8E46EB54BDD}.Release|Any CPU.Build.0 = Release|Any CPU

+		{711D1579-9228-47BA-9CB3-C237F7E8F403}.Debug|Any CPU.ActiveCfg = Debug|Any CPU

+		{711D1579-9228-47BA-9CB3-C237F7E8F403}.Debug|Any CPU.Build.0 = Debug|Any CPU

+		{711D1579-9228-47BA-9CB3-C237F7E8F403}.Release|Any CPU.ActiveCfg = Release|Any CPU

+		{711D1579-9228-47BA-9CB3-C237F7E8F403}.Release|Any CPU.Build.0 = Release|Any CPU

+		{87270607-F95C-4EED-AE69-57666863EFDF}.Debug|Any CPU.ActiveCfg = Debug|Any CPU

+		{87270607-F95C-4EED-AE69-57666863EFDF}.Debug|Any CPU.Build.0 = Debug|Any CPU

+		{87270607-F95C-4EED-AE69-57666863EFDF}.Release|Any CPU.ActiveCfg = Release|Any CPU

+		{87270607-F95C-4EED-AE69-57666863EFDF}.Release|Any CPU.Build.0 = Release|Any CPU

+		{5EE6E02C-A63F-4864-91F3-7375B4C50189}.Debug|Any CPU.ActiveCfg = Debug|Any CPU

+		{5EE6E02C-A63F-4864-91F3-7375B4C50189}.Debug|Any CPU.Build.0 = Debug|Any CPU

+		{5EE6E02C-A63F-4864-91F3-7375B4C50189}.Release|Any CPU.ActiveCfg = Release|Any CPU

+		{5EE6E02C-A63F-4864-91F3-7375B4C50189}.Release|Any CPU.Build.0 = Release|Any CPU

+		{7E7BBBDD-CE09-4298-B839-5EBDCA5D0DAF}.Debug|Any CPU.ActiveCfg = Debug|Any CPU

+		{7E7BBBDD-CE09-4298-B839-5EBDCA5D0DAF}.Debug|Any CPU.Build.0 = Debug|Any CPU

+		{7E7BBBDD-CE09-4298-B839-5EBDCA5D0DAF}.Release|Any CPU.ActiveCfg = Release|Any CPU

+		{7E7BBBDD-CE09-4298-B839-5EBDCA5D0DAF}.Release|Any CPU.Build.0 = Release|Any CPU

+		{E6BF8A7E-92F6-4761-A793-1EC709F7E2BF}.Debug|Any CPU.ActiveCfg = Debug|Any CPU

+		{E6BF8A7E-92F6-4761-A793-1EC709F7E2BF}.Debug|Any CPU.Build.0 = Debug|Any CPU

+		{E6BF8A7E-92F6-4761-A793-1EC709F7E2BF}.Release|Any CPU.ActiveCfg = Release|Any CPU

+		{E6BF8A7E-92F6-4761-A793-1EC709F7E2BF}.Release|Any CPU.Build.0 = Release|Any CPU

+		{6F4A4ABC-5E42-4293-80E6-0C38FE8C9EC5}.Debug|Any CPU.ActiveCfg = Debug|Any CPU

+		{6F4A4ABC-5E42-4293-80E6-0C38FE8C9EC5}.Debug|Any CPU.Build.0 = Debug|Any CPU

+		{6F4A4ABC-5E42-4293-80E6-0C38FE8C9EC5}.Release|Any CPU.ActiveCfg = Release|Any CPU

+		{6F4A4ABC-5E42-4293-80E6-0C38FE8C9EC5}.Release|Any CPU.Build.0 = Release|Any CPU

+		{A1066F8F-CE8A-4F60-9EFB-553C9E794435}.Debug|Any CPU.ActiveCfg = Debug|Any CPU

+		{A1066F8F-CE8A-4F60-9EFB-553C9E794435}.Debug|Any CPU.Build.0 = Debug|Any CPU

+		{A1066F8F-CE8A-4F60-9EFB-553C9E794435}.Release|Any CPU.ActiveCfg = Release|Any CPU

+		{A1066F8F-CE8A-4F60-9EFB-553C9E794435}.Release|Any CPU.Build.0 = Release|Any CPU

 	EndGlobalSection

 	GlobalSection(NestedProjects) = preSolution

-		{1B1B2197-61FB-416F-B6C8-845F2E5A0442} = {840309F0-435B-43A7-8471-8C2BE643889D}

-		{8F0A820E-F6AE-45A2-970E-7A3759693919} = {840309F0-435B-43A7-8471-8C2BE643889D}

 		{35DF9A1A-D988-4225-AFA3-06BB8EDEB559} = {A6345ECE-4C5E-400F-9130-886E343BF314}

 		{3ACF2613-E23F-42C2-925E-0BB4FC3AB1F7} = {A6345ECE-4C5E-400F-9130-886E343BF314}

-		{FB8FE4EB-B53B-464B-A5FD-9BF9D0F3EF9B} = {840309F0-435B-43A7-8471-8C2BE643889D}

 		{345934FF-CA81-4A4B-B137-9F198102C65F} = {BFE16D8E-EFC5-49F6-9854-DB001309B3B4}

 		{0B9B34D1-9362-45A9-9C21-816FD6959110} = {BFE16D8E-EFC5-49F6-9854-DB001309B3B4}

 		{4D9B5227-48DC-4A30-9263-AFB51DC01ABB} = {A6345ECE-4C5E-400F-9130-886E343BF314}

 		{13A797D1-7E13-4789-A167-8628B1641AC0} = {01A126FE-9D50-40F2-817B-E55F4065EA76}

 		{D44DB78D-9BAD-4AB6-A054-839ECA9D68D2} = {BFE16D8E-EFC5-49F6-9854-DB001309B3B4}

+		{ABAB8F42-A4BC-4ABF-AF1D-FDB40D87A91C} = {01A126FE-9D50-40F2-817B-E55F4065EA76}

+		{F94D35FF-E90E-4B86-B26E-A8E46EB54BDD} = {01A126FE-9D50-40F2-817B-E55F4065EA76}

+		{711D1579-9228-47BA-9CB3-C237F7E8F403} = {01A126FE-9D50-40F2-817B-E55F4065EA76}

+		{87270607-F95C-4EED-AE69-57666863EFDF} = {01A126FE-9D50-40F2-817B-E55F4065EA76}

+		{5EE6E02C-A63F-4864-91F3-7375B4C50189} = {01A126FE-9D50-40F2-817B-E55F4065EA76}

+		{7E7BBBDD-CE09-4298-B839-5EBDCA5D0DAF} = {01A126FE-9D50-40F2-817B-E55F4065EA76}

+		{E6BF8A7E-92F6-4761-A793-1EC709F7E2BF} = {01A126FE-9D50-40F2-817B-E55F4065EA76}

+		{6F4A4ABC-5E42-4293-80E6-0C38FE8C9EC5} = {A6345ECE-4C5E-400F-9130-886E343BF314}

+		{A1066F8F-CE8A-4F60-9EFB-553C9E794435} = {A6345ECE-4C5E-400F-9130-886E343BF314}

 	EndGlobalSection

 EndGlobal

diff --git a/LibMatrix/Extensions/CanonicalJsonSerializer.cs b/LibMatrix/Extensions/CanonicalJsonSerializer.cs
new file mode 100644
index 0000000..a6fbcf4
--- /dev/null
+++ b/LibMatrix/Extensions/CanonicalJsonSerializer.cs
@@ -0,0 +1,91 @@
+using System.Collections.Frozen;
+using System.Reflection;
+using System.Security.Cryptography;
+using System.Text.Encodings.Web;
+using System.Text.Json;
+using System.Text.Json.Nodes;
+using System.Text.Json.Serialization;
+using System.Text.Json.Serialization.Metadata;
+using System.Text.Unicode;
+using ArcaneLibs.Extensions;
+
+namespace LibMatrix.Extensions;
+
+public static class CanonicalJsonSerializer {
+    // TODO: Alphabetise dictionaries
+    private static JsonSerializerOptions _options => new() {
+        WriteIndented = false,
+        Encoder = UnicodeJsonEncoder.Singleton,
+    };
+
+    private static readonly FrozenSet<PropertyInfo> JsonSerializerOptionsProperties = typeof(JsonSerializerOptions)
+        .GetProperties(BindingFlags.Public | BindingFlags.Instance)
+        .Where(x => x.SetMethod != null && x.GetMethod != null)
+        .ToFrozenSet();
+
+    private static JsonSerializerOptions MergeOptions(JsonSerializerOptions? inputOptions) {
+        var newOptions = _options;
+        if (inputOptions == null)
+            return newOptions;
+        
+        foreach (var property in JsonSerializerOptionsProperties) {
+            if(property.Name == nameof(JsonSerializerOptions.Encoder))
+                continue;
+            if (property.Name == nameof(JsonSerializerOptions.WriteIndented))
+                continue;
+                
+            var value = property.GetValue(inputOptions);
+            // if (value == null)
+                // continue;
+            property.SetValue(newOptions, value);
+        }
+
+        return newOptions;
+    }
+
+#region STJ API
+
+    public static String Serialize<TValue>(TValue value, JsonSerializerOptions? options = null) {
+        var newOptions = MergeOptions(options);
+
+        return System.Text.Json.JsonSerializer.SerializeToNode(value, options) // We want to allow passing custom converters for eg. double/float -> string here...
+            .SortProperties()!
+            .CanonicalizeNumbers()!
+            .ToJsonString(newOptions);
+        
+            
+        // System.Text.Json.JsonSerializer.SerializeToNode(System.Text.Json.JsonSerializer.Deserialize<dynamic>("{\n    \"a\": -0,\n    \"b\": 1e10\n}")).ToJsonString();
+        
+    }
+
+    public static String Serialize(object value, Type inputType, JsonSerializerOptions? options = null) => JsonSerializer.Serialize(value, inputType, _options);
+    // public static String Serialize<TValue>(TValue value, JsonTypeInfo<TValue> jsonTypeInfo) => JsonSerializer.Serialize(value, jsonTypeInfo, _options);
+    // public static String Serialize(Object value, JsonTypeInfo jsonTypeInfo) 
+
+#endregion
+
+    private static partial class JsonExtensions {
+        public static Action<JsonTypeInfo> AlphabetizeProperties(Type type) {
+            return typeInfo => {
+                if (typeInfo.Kind != JsonTypeInfoKind.Object || !type.IsAssignableFrom(typeInfo.Type))
+                    return;
+                AlphabetizeProperties()(typeInfo);
+            };
+        }
+
+        public static Action<JsonTypeInfo> AlphabetizeProperties() {
+            return static typeInfo => {
+                if (typeInfo.Kind == JsonTypeInfoKind.Dictionary) { }
+
+                if (typeInfo.Kind != JsonTypeInfoKind.Object)
+                    return;
+                var properties = typeInfo.Properties.OrderBy(p => p.Name, StringComparer.Ordinal).ToList();
+                typeInfo.Properties.Clear();
+                for (int i = 0; i < properties.Count; i++) {
+                    properties[i].Order = i;
+                    typeInfo.Properties.Add(properties[i]);
+                }
+            };
+        }
+    }
+}
\ No newline at end of file
diff --git a/LibMatrix/Extensions/UnicodeJsonEncoder.cs b/LibMatrix/Extensions/UnicodeJsonEncoder.cs
new file mode 100644
index 0000000..ae58263
--- /dev/null
+++ b/LibMatrix/Extensions/UnicodeJsonEncoder.cs
@@ -0,0 +1,173 @@
+// LibMatrix: File sourced from https://github.com/dotnet/runtime/pull/87147/files under the MIT license.
+
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Text;
+using System.Text.Encodings.Web;
+
+namespace LibMatrix.Extensions;
+
+internal sealed class UnicodeJsonEncoder : JavaScriptEncoder
+{
+    internal static readonly UnicodeJsonEncoder Singleton = new UnicodeJsonEncoder();
+
+    private readonly bool _preferHexEscape;
+    private readonly bool _preferUppercase;
+
+    public UnicodeJsonEncoder()
+        : this(preferHexEscape: false, preferUppercase: false)
+    {
+    }
+
+    public UnicodeJsonEncoder(bool preferHexEscape, bool preferUppercase)
+    {
+        _preferHexEscape = preferHexEscape;
+        _preferUppercase = preferUppercase;
+    }
+
+    public override int MaxOutputCharactersPerInputCharacter => 6; // "\uXXXX" for a single char ("\uXXXX\uYYYY" [12 chars] for supplementary scalar value)
+
+    public override unsafe int FindFirstCharacterToEncode(char* text, int textLength)
+    {
+        for (int index = 0; index < textLength; ++index)
+        {
+            char value = text[index];
+
+            if (NeedsEncoding(value))
+            {
+                return index;
+            }
+        }
+
+        return -1;
+    }
+
+    public override unsafe bool TryEncodeUnicodeScalar(int unicodeScalar, char* buffer, int bufferLength, out int numberOfCharactersWritten)
+    {
+        bool encode = WillEncode(unicodeScalar);
+
+        if (!encode)
+        {
+            Span<char> span = new Span<char>(buffer, bufferLength);
+            int spanWritten;
+            bool succeeded = new Rune(unicodeScalar).TryEncodeToUtf16(span, out spanWritten);
+            numberOfCharactersWritten = spanWritten;
+            return succeeded;
+        }
+
+        if (!_preferHexEscape && unicodeScalar <= char.MaxValue && HasTwoCharacterEscape((char)unicodeScalar))
+        {
+            if (bufferLength < 2)
+            {
+                numberOfCharactersWritten = 0;
+                return false;
+            }
+
+            buffer[0] = '\\';
+            buffer[1] = GetTwoCharacterEscapeSuffix((char)unicodeScalar);
+            numberOfCharactersWritten = 2;
+            return true;
+        }
+        else
+        {
+            if (bufferLength < 6)
+            {
+                numberOfCharactersWritten = 0;
+                return false;
+            }
+
+            buffer[0] = '\\';
+            buffer[1] = 'u';
+            buffer[2] = '0';
+            buffer[3] = '0';
+            buffer[4] = ToHexDigit((unicodeScalar & 0xf0) >> 4, _preferUppercase);
+            buffer[5] = ToHexDigit(unicodeScalar & 0xf, _preferUppercase);
+            numberOfCharactersWritten = 6;
+            return true;
+        }
+    }
+
+    public override bool WillEncode(int unicodeScalar)
+    {
+        if (unicodeScalar > char.MaxValue)
+        {
+            return false;
+        }
+
+        return NeedsEncoding((char)unicodeScalar);
+    }
+
+    // https://datatracker.ietf.org/doc/html/rfc8259#section-7
+    private static bool NeedsEncoding(char value)
+    {
+        if (value == '"' || value == '\\')
+        {
+            return true;
+        }
+
+        return value <= '\u001f';
+    }
+
+    private static bool HasTwoCharacterEscape(char value)
+    {
+        // RFC 8259, Section 7, "char = " BNF
+        switch (value)
+        {
+            case '"':
+            case '\\':
+            case '/':
+            case '\b':
+            case '\f':
+            case '\n':
+            case '\r':
+            case '\t':
+                return true;
+            default:
+                return false;
+        }
+    }
+
+    private static char GetTwoCharacterEscapeSuffix(char value)
+    {
+        // RFC 8259, Section 7, "char = " BNF
+        switch (value)
+        {
+            case '"':
+                return '"';
+            case '\\':
+                return '\\';
+            case '/':
+                return '/';
+            case '\b':
+                return 'b';
+            case '\f':
+                return 'f';
+            case '\n':
+                return 'n';
+            case '\r':
+                return 'r';
+            case '\t':
+                return 't';
+            default:
+                throw new ArgumentOutOfRangeException(nameof(value));
+        }
+    }
+
+    private static char ToHexDigit(int value, bool uppercase)
+    {
+        if (value > 0xf)
+        {
+            throw new ArgumentOutOfRangeException(nameof(value));
+        }
+
+        if (value < 10)
+        {
+            return (char)(value + '0');
+        }
+        else
+        {
+            return (char)(value - 0xa + (uppercase ? 'A' : 'a'));
+        }
+    }
+}
\ No newline at end of file
diff --git a/LibMatrix/LibMatrix.csproj b/LibMatrix/LibMatrix.csproj
index d0511ea..e037672 100644
--- a/LibMatrix/LibMatrix.csproj
+++ b/LibMatrix/LibMatrix.csproj
@@ -8,6 +8,7 @@
 
         <Optimize>true</Optimize>
         <EmitCompilerGeneratedFiles>true</EmitCompilerGeneratedFiles>
+        <AllowUnsafeBlocks>true</AllowUnsafeBlocks> <!-- Required for UnicodeJsonEncoder... -->
     </PropertyGroup>
 
     <ItemGroup>