Create OverwriteBenchmarks.cs

Author: SimonCropp

src/Benchmarks/OverwriteBenchmarks.cs

@@ -0,0 +1,200 @@
+[MemoryDiagnoser]
+[SimpleJob(warmupCount: 3, iterationCount: 5)]
+public class OverwriteBenchmarks
+{
+    StringBuilder smallBuilder = null!;
+    StringBuilder mediumBuilder = null!;
+    StringBuilder largeBuilder = null!;
+    StringBuilder multiChunkBuilder = null!;
+
+    [GlobalSetup]
+    public void Setup()
+    {
+        smallBuilder = new StringBuilder("Hello World! This is a small test string.");
+
+        mediumBuilder = new StringBuilder();
+        for (var i = 0; i < 100; i++)
+        {
+            mediumBuilder.Append("This is sentence number ");
+            mediumBuilder.Append(i);
+            mediumBuilder.Append(". ");
+        }
+
+        largeBuilder = new StringBuilder();
+        for (var i = 0; i < 10000; i++)
+        {
+            largeBuilder.Append("Content ");
+        }
+
+        // Force multiple chunks
+        multiChunkBuilder = new StringBuilder();
+        for (var i = 0; i < 50; i++)
+        {
+            multiChunkBuilder.Append("Chunk ");
+            multiChunkBuilder.Append(i);
+            multiChunkBuilder.Append(" data. ");
+        }
+    }
+
+    // Same length replacements - most common case
+    [Benchmark]
+    public void SameLength_Small_SingleChar()
+    {
+        var builder = new StringBuilder(smallBuilder.ToString());
+        builder.Overwrite("X", 0, 1);
+    }
+
+    [Benchmark]
+    public void SameLength_Small_FiveChars()
+    {
+        var builder = new StringBuilder(smallBuilder.ToString());
+        builder.Overwrite("XXXXX", 6, 5);
+    }
+
+    [Benchmark]
+    public void SameLength_Small_TenChars()
+    {
+        var builder = new StringBuilder(smallBuilder.ToString());
+        builder.Overwrite("XXXXXXXXXX", 10, 10);
+    }
+
+    [Benchmark]
+    public void SameLength_Medium_TenChars()
+    {
+        var builder = new StringBuilder(mediumBuilder.ToString());
+        builder.Overwrite("REPLACEMENT", 500, 11);
+    }
+
+    [Benchmark]
+    public void SameLength_Large_TenChars()
+    {
+        var builder = new StringBuilder(largeBuilder.ToString());
+        builder.Overwrite("REPLACEMENT", 5000, 11);
+    }
+
+    [Benchmark]
+    public void SameLength_MultiChunk_SpanningChunks()
+    {
+        var builder = new StringBuilder(multiChunkBuilder.ToString());
+        builder.Overwrite("REPLACED", 50, 8);
+    }
+
+    // Shorter replacements
+    [Benchmark]
+    public void Shorter_Small_ReplaceWithEmpty()
+    {
+        var builder = new StringBuilder(smallBuilder.ToString());
+        builder.Overwrite("", 6, 5);
+    }
+
+    [Benchmark]
+    public void Shorter_Small_ReplaceWithOne()
+    {
+        var builder = new StringBuilder(smallBuilder.ToString());
+        builder.Overwrite("X", 6, 5);
+    }
+
+    [Benchmark]
+    public void Shorter_Medium()
+    {
+        var builder = new StringBuilder(mediumBuilder.ToString());
+        builder.Overwrite("SHORT", 500, 20);
+    }
+
+    [Benchmark]
+    public void Shorter_Large()
+    {
+        var builder = new StringBuilder(largeBuilder.ToString());
+        builder.Overwrite("X", 5000, 100);
+    }
+
+    // Longer replacements
+    [Benchmark]
+    public void Longer_Small()
+    {
+        var builder = new StringBuilder(smallBuilder.ToString());
+        builder.Overwrite("MUCH LONGER REPLACEMENT", 6, 5);
+    }
+
+    [Benchmark]
+    public void Longer_Medium()
+    {
+        var builder = new StringBuilder(mediumBuilder.ToString());
+        builder.Overwrite("THIS IS A MUCH LONGER REPLACEMENT STRING", 500, 10);
+    }
+
+    [Benchmark]
+    public void Longer_Large()
+    {
+        var builder = new StringBuilder(largeBuilder.ToString());
+        builder.Overwrite("VERY LONG REPLACEMENT TEXT HERE", 5000, 10);
+    }
+
+    // Position-based tests
+    [Benchmark]
+    public void SameLength_AtStart()
+    {
+        var builder = new StringBuilder(mediumBuilder.ToString());
+        builder.Overwrite("REPLACED", 0, 8);
+    }
+
+    [Benchmark]
+    public void SameLength_AtEnd()
+    {
+        var builder = new StringBuilder(mediumBuilder.ToString());
+        var length = builder.Length;
+        builder.Overwrite("REPLACED", length - 8, 8);
+    }
+
+    [Benchmark]
+    public void SameLength_InMiddle()
+    {
+        var builder = new StringBuilder(mediumBuilder.ToString());
+        var length = builder.Length;
+        builder.Overwrite("REPLACED", length / 2, 8);
+    }
+
+    // Multiple operations
+    [Benchmark]
+    public void MultipleOverwrites_SameLength()
+    {
+        var builder = new StringBuilder(mediumBuilder.ToString());
+        for (var i = 0; i < 10; i++)
+        {
+            builder.Overwrite("REPLACE", i * 100, 7);
+        }
+    }
+
+    [Benchmark]
+    public void MultipleOverwrites_DifferentLengths()
+    {
+        var builder = new StringBuilder(mediumBuilder.ToString());
+        builder.Overwrite("SHORT", 100, 10);
+        builder.Overwrite("MUCH LONGER", 200, 5);
+        builder.Overwrite("SAME", 300, 4);
+    }
+
+    // Edge cases
+    [Benchmark]
+    public void EdgeCase_VeryLongReplacement()
+    {
+        var builder = new StringBuilder(mediumBuilder.ToString());
+        var longString = new string('X', 500);
+        builder.Overwrite(longString, 100, 50);
+    }
+
+    [Benchmark]
+    public void EdgeCase_SingleCharReplace()
+    {
+        var builder = new StringBuilder(largeBuilder.ToString());
+        builder.Overwrite("Y", 5000, 1);
+    }
+
+    [Benchmark]
+    public void EdgeCase_NearChunkBoundary()
+    {
+        var builder = new StringBuilder(multiChunkBuilder.ToString());
+        // Try to hit near chunk boundaries
+        builder.Overwrite("BOUNDARY", 15, 8);
+    }
+}