aspnetcore/src/Microsoft.AspNet.Razor/Common/HashCodeCombiner.cs

62 lines
1.6 KiB
C#

// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
using System.Collections;
using System.Collections.Generic;
namespace Microsoft.Internal.Web.Utils
{
internal class HashCodeCombiner
{
private long _combinedHash64 = 0x1505L;
public int CombinedHash
{
get { return _combinedHash64.GetHashCode(); }
}
public HashCodeCombiner Add(IEnumerable e)
{
if (e == null)
{
Add(0);
}
else
{
var count = 0;
foreach (object o in e)
{
Add(o);
count++;
}
Add(count);
}
return this;
}
public HashCodeCombiner Add(int i)
{
_combinedHash64 = ((_combinedHash64 << 5) + _combinedHash64) ^ i;
return this;
}
public HashCodeCombiner Add(object o)
{
var hashCode = (o != null) ? o.GetHashCode() : 0;
Add(hashCode);
return this;
}
public HashCodeCombiner Add<TValue>(TValue value, IEqualityComparer<TValue> comparer)
{
var hashCode = value != null ? comparer.GetHashCode(value) : 0;
return Add(hashCode);
}
public static HashCodeCombiner Start()
{
return new HashCodeCombiner();
}
}
}