feat: use 64 bytes as threshold

Author: unsafePtr

src/Base58Encoding.Benchmarks/CountLeadingZerosBenchmark.cs

@@ -12,6 +12,7 @@ namespace Base58Encoding.Benchmarks;
 [SimpleJob(RuntimeMoniker.Net90)]
 [SimpleJob(RuntimeMoniker.Net10_0)]
 [HideColumns("Job", "Error", "StdDev", "Median", "RatioSD")]
+[DisassemblyDiagnoser]
 public class CountLeadingZerosBenchmark
 {
     private static Lazy<byte[][]> _lazyTestData = new(() =>
@@ -93,7 +94,7 @@ public int SimdOnly()
         return totalCount;
     }
 
-    [Benchmark(Baseline = true, Description = "Combined (Current)")]
+    [Benchmark(Baseline = true, Description = "Combined (Current) - 16bytes SIMD threshold")]
     public int Combined()
     {
         int totalCount = 0;
@@ -209,11 +210,7 @@ private static int CountLeadingZerosSimdImpl(ReadOnlySpan<byte> data, out int pr
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     private static int CountLeadingZerosCombinedImpl(ReadOnlySpan<byte> data)
     {
-        // intentionally commenting out, since other methods won't have it also
-        //if (data.Length == 0)
-        //    return 0;
-
-        if (data.Length < 16)
+        if (data.Length < 64)
             return CountLeadingZerosScalarImpl(data);
 
         int count = CountLeadingZerosSimdImpl(data, out int processed);

src/Base58Encoding.Tests/SimpleLeadingZerosTest.cs

@@ -0,0 +1,30 @@
+namespace Base58Encoding.Tests;
+
+public class SimpleLeadingZerosTest
+{
+    [Fact]
+    public void BitcoinAddress_CountLeadingZerosMultipleWays_SameResult()
+    {
+        var address = "1111111111111111111114oLvT2";
+        var decoded = Base58.Bitcoin.Decode(address);
+
+        // Count leading zeros manually
+        int manualCount = 0;
+        for (int i = 0; i < decoded.Length; i++)
+        {
+            if (decoded[i] != 0) break;
+            manualCount++;
+        }
+
+        // Test SIMD
+        int simdCount = Base58.CountLeadingZerosSimd(decoded, out int processed);
+        var simdScalarCount = 0;
+        if (simdCount >= processed)
+        {
+            int remaining = Base58.CountLeadingZerosScalar(decoded.AsSpan(simdCount));
+            simdScalarCount = simdCount + remaining;
+        }
+
+        Assert.Equal(simdScalarCount, manualCount);
+    }
+}

src/Base58Encoding/Base58Encoding.csproj

@@ -1,29 +1,34 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
-  <PropertyGroup>
-    <TargetFrameworks>net9.0;net10.0</TargetFrameworks>
-    <ImplicitUsings>enable</ImplicitUsings>
-    <Nullable>enable</Nullable>
+	<PropertyGroup>
+		<TargetFrameworks>net9.0;net10.0</TargetFrameworks>
+		<ImplicitUsings>enable</ImplicitUsings>
+		<Nullable>enable</Nullable>
 
-    <PackageId>Base58Encoding</PackageId>
-    <Authors>Nikolay Zdravkov</Authors>
-    <Description>A high-performance Base58 encoding/decoding library for .NET</Description>
-    <PackageTags>base58;encoding;bitcoin;cryptocurrency</PackageTags>
-    <PackageProjectUrl>https://github.com/unsafePtr/Base58Encoding</PackageProjectUrl>
-    <RepositoryUrl>https://github.com/unsafePtr/Base58Encoding</RepositoryUrl>
-    <PackageLicenseExpression>MIT</PackageLicenseExpression>
-    <PackageReadmeFile>README.md</PackageReadmeFile>
-    <GeneratePackageOnBuild>false</GeneratePackageOnBuild>
-  </PropertyGroup>
+		<PackageId>Base58Encoding</PackageId>
+		<Authors>Nikolay Zdravkov</Authors>
+		<Description>A high-performance Base58 encoding/decoding library for .NET</Description>
+		<PackageTags>base58;encoding;bitcoin;cryptocurrency</PackageTags>
+		<PackageProjectUrl>https://github.com/unsafePtr/Base58Encoding</PackageProjectUrl>
+		<RepositoryUrl>https://github.com/unsafePtr/Base58Encoding</RepositoryUrl>
+		<PackageLicenseExpression>MIT</PackageLicenseExpression>
+		<PackageReadmeFile>README.md</PackageReadmeFile>
+		<GeneratePackageOnBuild>false</GeneratePackageOnBuild>
+	</PropertyGroup>
 
-  <ItemGroup>
-    <AssemblyAttribute Include="System.Runtime.CompilerServices.InternalsVisibleTo">
-      <_Parameter1>Base58Encoding.Benchmarks</_Parameter1>
-    </AssemblyAttribute>
-  </ItemGroup>
+	<ItemGroup>
+		<AssemblyAttribute Include="System.Runtime.CompilerServices.InternalsVisibleTo">
+			<_Parameter1>Base58Encoding.Benchmarks</_Parameter1>
+		</AssemblyAttribute>
+	</ItemGroup>
+	<ItemGroup>
+		<AssemblyAttribute Include="System.Runtime.CompilerServices.InternalsVisibleTo">
+			<_Parameter1>Base58Encoding.Tests</_Parameter1>
+		</AssemblyAttribute>
+	</ItemGroup>
 
-  <ItemGroup>
-    <None Include="..\..\README.md" Pack="true" PackagePath="\"/>
-  </ItemGroup>
+	<ItemGroup>
+		<None Include="..\..\README.md" Pack="true" PackagePath="\"/>
+	</ItemGroup>
 
 </Project>

src/Base58Encoding/CountLeading.Base58.cs

@@ -4,15 +4,13 @@
 using System.Runtime.Intrinsics;
 
 namespace Base58Encoding;
+
 public partial class Base58
 {
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     internal static int CountLeadingZeros(ReadOnlySpan<byte> data)
     {
-        if (data.Length == 0)
-            return 0;
-
-        if (data.Length < 16)
+        if (data.Length < 64)
             return CountLeadingZerosScalar(data);
 
         int count = CountLeadingZerosSimd(data, out int processed);