CultureAwareComparer.cs

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using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.Runtime.CompilerServices;
using System.Runtime.Serialization;
 
namespace System;
 
[Serializable]
[TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
public sealed class CultureAwareComparer : StringComparer, ISerializable
{
    internal static readonly CultureAwareComparer InvariantCaseSensitiveInstance = new CultureAwareComparer(CompareInfo.Invariant, CompareOptions.None);
 
    internal static readonly CultureAwareComparer InvariantIgnoreCaseInstance = new CultureAwareComparer(CompareInfo.Invariant, CompareOptions.IgnoreCase);
 
    private readonly CompareInfo _compareInfo;
 
    private readonly CompareOptions _options;
 
    internal CultureAwareComparer(CultureInfo culture, CompareOptions options)
        : this(culture.CompareInfo, options)
    {
    }
 
    internal CultureAwareComparer(CompareInfo compareInfo, CompareOptions options)
    {
        _compareInfo = compareInfo;
        if (((uint)options & 0xDFFFFFE0u) != 0)
        {
            throw new ArgumentException(SR.Argument_InvalidFlag, "options");
        }
        _options = options;
    }
 
    private CultureAwareComparer(SerializationInfo info, StreamingContext context)
    {
        _compareInfo = (CompareInfo)info.GetValue("_compareInfo", typeof(CompareInfo));
        bool boolean = info.GetBoolean("_ignoreCase");
        object valueNoThrow = info.GetValueNoThrow("_options", typeof(CompareOptions));
        if (valueNoThrow != null)
        {
            _options = (CompareOptions)valueNoThrow;
        }
        _options |= (CompareOptions)(boolean ? 1 : 0);
    }
 
    public override int Compare(string? x, string? y)
    {
        if ((object)x == y)
        {
            return 0;
        }
        if (x == null)
        {
            return -1;
        }
        if (y == null)
        {
            return 1;
        }
        return _compareInfo.Compare(x, y, _options);
    }
 
    public override bool Equals(string? x, string? y)
    {
        if ((object)x == y)
        {
            return true;
        }
        if (x == null || y == null)
        {
            return false;
        }
        return _compareInfo.Compare(x, y, _options) == 0;
    }
 
    public override int GetHashCode(string obj)
    {
        if (obj == null)
        {
            throw new ArgumentNullException("obj");
        }
        return _compareInfo.GetHashCode(obj, _options);
    }
 
    public override bool Equals([NotNullWhen(true)] object? obj)
    {
        if (obj is CultureAwareComparer cultureAwareComparer && _options == cultureAwareComparer._options)
        {
            return _compareInfo.Equals(cultureAwareComparer._compareInfo);
        }
        return false;
    }
 
    public override int GetHashCode()
    {
        return _compareInfo.GetHashCode() ^ (int)(_options & (CompareOptions)2147483647);
    }
 
    public void GetObjectData(SerializationInfo info, StreamingContext context)
    {
        info.AddValue("_compareInfo", _compareInfo);
        info.AddValue("_options", _options);
        info.AddValue("_ignoreCase", (_options & CompareOptions.IgnoreCase) != 0);
    }
 
    private protected override bool IsWellKnownCultureAwareComparerCore([NotNullWhen(true)] out CompareInfo compareInfo, out CompareOptions compareOptions)
    {
        compareInfo = _compareInfo;
        compareOptions = _options;
        return true;
    }
}