add SwissTable-style mirroring, compaction scopes, and probe-safe APIs

      Implemented mirrored control-byte padding to allow SIMD probing across table boundaries without branches.
      Normalized all slot addressing using power-of-two masking to prevent out-of-bounds entry access.
      Rewrote Insert, InsertOrUpdate, Get, Update, Remove, Contains, and GetValueRefOrAddDefault to be mirror-safe and slot-normalized.
      Added in-place table Rehash() to compact tombstones without resizing.
      Added automatic rehash trigger based on tombstone pressure.
      Introduced rehash suppression scopes (BeginRehashScope / EndRehashScope) for O(n) bulk deletes without rebuild thrashing.
      Fixed enumeration (Entries, Keys, Values) to avoid mirrored tail duplication.
      Hardened probe logic to preserve SwissTable invariants under wrap-around SIMD reads.
      This change set brings DenseMap’s internal behavior in line with Abseil SwissTable while maintaining API stability.

Author: Wsm2110

.github/workflows/dotnet.yml

@@ -1,6 +1,3 @@
-# This workflow will build a .NET project
-# For more information see: https://docs.github.com/en/actions/automating-builds-and-tests/building-and-testing-net
-
 name: .NET
 
 on:
@@ -11,24 +8,21 @@ on:
 
 jobs:
   build:
-
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v4
-    - name: Setup .NET
-      uses: actions/setup-dotnet@v4
-      with:
-        dotnet-version: 9.0.x
+      - uses: actions/checkout@v4
 
-    - name: Restore dependencies
-      run: dotnet restore  Faster.Map.sln
+      - name: Setup .NET
+        uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: 10.0.x
 
-    - name: Restore nuget packages
-      run: nuget restore Faster.Map.sln
+      - name: Restore
+        run: dotnet restore Faster.Map.sln
 
-    - name: Build
-      run: dotnet build --no-restore
+      - name: Build
+        run: dotnet build Faster.Map.sln --configuration Release --no-restore
 
-    - name: Test
-      run: dotnet test --no-build --verbosity normal
+      - name: Test
+        run: dotnet test Faster.Map.sln --configuration Release --no-build --verbosity normal

Faster.Map.sln

@@ -1,7 +1,7 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio Version 17
-VisualStudioVersion = 17.0.31825.309
+# Visual Studio Version 18
+VisualStudioVersion = 18.3.11222.16 d18.3
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Faster.Map.Benchmark", "benchmarks\Faster.Map.Benchmark\Faster.Map.Benchmark.csproj", "{1643EE6A-F080-49DE-817E-C0698BDCA3C6}"
 EndProject
@@ -27,6 +27,11 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Faster.Map.Hash.Tests", "un
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Faster.Map.BlitzMap.Tests", "unittests\Faster.Map.BlitzMap.Tests\Faster.Map.BlitzMap.Tests.csproj", "{E35C4248-3003-9067-9112-A58F11053905}"
 EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution Items", "{B57801ED-1345-4B7E-AC0E-845643C09CBC}"
+	ProjectSection(SolutionItems) = preProject
+		.github\workflows\dotnet.yml = .github\workflows\dotnet.yml
+	EndProjectSection
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU

benchmarks/Faster.Map.Benchmark/AddAndResizeBenchmark.cs

@@ -63,7 +63,7 @@ public void DenseMap()
         {
             foreach (var key in keys)
             {
-                _denseMap.Emplace(key, key);
+                _denseMap.InsertOrUpdate(key, key);
             }
         }
 

benchmarks/Faster.Map.Benchmark/AddBenchmark.cs

@@ -85,7 +85,7 @@ public void DenseMap()
             for (int i = 0; i < keys.Length; i++)
             {
                 var key = keys[i];
-                _dense.Emplace(key, key);
+                _dense.InsertOrUpdate(key, key);
             }
         }
 

benchmarks/Faster.Map.Benchmark/EnumerableBenchmark.cs

@@ -66,7 +66,7 @@ public void Setup()
         foreach (var key in keys)
         {
             _dictionary.Add(key, key);
-            _denseMap.Emplace(key, key);
+            _denseMap.InsertOrUpdate(key, key);
             _blitz.Insert(key, key);
             _robinHoodMap.Emplace(key, key);
         }

benchmarks/Faster.Map.Benchmark/GetBenchmark.cs

@@ -65,21 +65,21 @@ public void Setup()
             foreach (var key in keys)
             {
                 _dictionary.Add(key, key);
-                _denseMap.Emplace(key, key);
+                _denseMap.InsertOrUpdate(key, key);
                 _blitz.Insert(key, key);           
                 _robinHoodMap.Emplace(key, key);
             }
         }
 
-        [Benchmark]
-        public void BlitzMap()
-        {
-            for (int i = 0; i < keys.Length; i++)
-            {
-                var key = keys[i];
-                _blitz.Get(key, out var _);
-            }
-        }
+        //[Benchmark]
+        //public void BlitzMap()
+        //{
+        //    for (int i = 0; i < keys.Length; i++)
+        //    {
+        //        var key = keys[i];
+        //        _blitz.Get(key, out var _);
+        //    }
+        //}
 
         [Benchmark]
         public void DenseMap()

benchmarks/Faster.Map.Benchmark/LargeStringBenchmark.cs

@@ -73,7 +73,7 @@ public void Setup()
             {
                 var key = keys[i];
                 _dictionary.Add(key, key);
-                _dense.Emplace(key, key);
+                _dense.InsertOrUpdate(key, key);
                 _robinhoodMap.Emplace(key, key);
                 _blitzMap.Insert(key, key);
             }

benchmarks/Faster.Map.Benchmark/RemoveBenchmark.cs

@@ -91,7 +91,7 @@ public void IterationSetupX(BenchmarkCase benchmarkCase)
                         _blitz.Insert(key, key);
                         break;
                     case nameof(DenseMap):
-                        _denseMap.Emplace(key, key);
+                        _denseMap.InsertOrUpdate(key, key);
                         break;
                     case nameof(RobinhoodMap):
                         _robinHoodMap.Emplace(key, key);

benchmarks/Faster.Map.Benchmark/StringBenchmark.cs

@@ -65,7 +65,7 @@ public void Setup()
             {
                 var key = keys[i];
                 _dictionary.Add(key, key);
-                _dense.Emplace(key, key);
+                _dense.InsertOrUpdate(key, key);
                 _robinhoodMap.Emplace(key, key);
                 _blitzMap.Insert(key, key);
             }

benchmarks/Faster.Map.Benchmark/UpdateBenchmark.cs

@@ -67,7 +67,7 @@ public void Setup()
             foreach (var key in keys)
             {
                 _dictionary.Add(key, key);
-                _denseMap.Emplace(key, key);
+                _denseMap.InsertOrUpdate(key, key);
                 _blitz.Insert(key, key);
                 _robinHoodMap.Emplace(key, key);
             }