CompatibleIComparer.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / FX-1434 / FX-1434 / 1.0 / untmp / whidbey / REDBITS / ndp / fx / src / Misc / CompatibleIComparer.cs / 1 / CompatibleIComparer.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

/* 
 * This class is used to create hashcodes that are Everett Compatible. 
 *
 * Copyright (c) 2004 Microsoft Corporation 
 */

namespace System.Collections.Specialized {
 
    using Microsoft.Win32;
    using System.Collections; 
    using System.Runtime.Serialization; 
    using System.Globalization;
 
    internal class BackCompatibleStringComparer : IEqualityComparer {

        static internal IEqualityComparer Default = new BackCompatibleStringComparer();
 
        internal BackCompatibleStringComparer() {
        } 
 
        //This comes from VS# 434837 and is specifically written to get backcompat
        public static int GetHashCode(string obj) { 
            unsafe {
                fixed (char* src = obj) {
                    int hash = 5381;
                    int c; 
                    char* szStr = src;
 
                    while ((c = *szStr) != 0) { 
                        hash = ((hash << 5) + hash) ^ c;
                        ++szStr; 
                    }
                    return hash;
                }
            } 
        }
 
        bool IEqualityComparer.Equals(Object a, Object b) { 
            return Object.Equals(a, b);
        } 

        public virtual int GetHashCode(Object o) {
            String obj = o as string;
            if (obj == null) { 
                return o.GetHashCode();
            } 
 
            return BackCompatibleStringComparer.GetHashCode(obj);
        } 
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

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