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Improve hash function quality by replacing multiplicative algorithm with System.HashCode #181

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Improve hash function quality by replacing multiplicative algorithm with System.HashCode #181

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814b462
Initial commit with task details for issue #5
konard Sep 14, 2025
38fd456
Improve hash function quality by replacing multiplicative algorithm w…
konard Sep 14, 2025
cb45326
'Auto-commit changes made by Claude
konard Sep 14, 2025
d850edd
Remove CLAUDE.md - Claude command completed
konard Sep 14, 2025
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1 change: 1 addition & 0 deletions .gitignore
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Original file line number Diff line number Diff line change
Expand Up @@ -339,3 +339,4 @@ ASALocalRun/

# Local History for Visual Studio Code
.history/
experiments/
9 changes: 5 additions & 4 deletions csharp/Platform.Collections/Lists/IListExtensions.cs
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Expand Up @@ -336,17 +336,18 @@ public static void ForEach<T>(this IList<T> list, Action<T> action)
/// <para>Хэш-код списка.</para>
/// </returns>
/// <remarks>
/// Based on http://stackoverflow.com/questions/263400/what-is-the-best-algorithm-for-an-overridden-system-object-gethashcode
/// Uses System.HashCode for optimal hash combining as recommended in modern .NET applications.
/// This provides better distribution and collision resistance compared to simple multiplicative hashing.
/// </remarks>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static int GenerateHashCode<T>(this IList<T> list)
{
var hashAccumulator = 17;
var hash = new HashCode();
for (var i = 0; i < list.Count; i++)
{
hashAccumulator = unchecked((hashAccumulator * 23) + list[i].GetHashCode());
hash.Add(list[i]);
}
return hashAccumulator;
return hash.ToHashCode();
}

/// <summary>
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4 changes: 2 additions & 2 deletions csharp/Platform.Collections/Platform.Collections.csproj
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Expand Up @@ -4,7 +4,7 @@
<Description>LinksPlatform's Platform.Collections Class Library</Description>
<Copyright>konard;tynkute</Copyright>
<AssemblyTitle>Platform.Collections</AssemblyTitle>
<VersionPrefix>0.4.0</VersionPrefix>
<VersionPrefix>0.5.0</VersionPrefix>
<Authors>konard;tynkute</Authors>
<TargetFramework>net8</TargetFramework>
<AssemblyName>Platform.Collections</AssemblyName>
Expand All @@ -24,7 +24,7 @@
<IncludeSymbols>true</IncludeSymbols>
<SymbolPackageFormat>snupkg</SymbolPackageFormat>
<LangVersion>latest</LangVersion>
<PackageReleaseNotes>Update target framework from net7 to net8.</PackageReleaseNotes>
<PackageReleaseNotes>Improve hash function quality by replacing simple multiplicative algorithm with System.HashCode for better distribution and collision resistance.</PackageReleaseNotes>
<Nullable>enable</Nullable>
</PropertyGroup>

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