HashCodeCombiner.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / xsp / System / Web / Util / HashCodeCombiner.cs / 1305376 / HashCodeCombiner.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

/* 
 * HashCodeCombiner class 
 *
 * Copyright (c) 1999 Microsoft Corporation 
 */

namespace System.Web.Util {
using System.Text; 
using System.Collections;
using System.IO; 
using System.Globalization; 

/* 
 * Class used to combine several hashcodes into a single hashcode
 */
internal class HashCodeCombiner {
 
    private long _combinedHash;
 
    internal HashCodeCombiner() { 
       // Start with a seed (obtained from String.GetHashCode implementation)
       _combinedHash = 5381; 
    }

    internal HashCodeCombiner(long initialCombinedHash)   {
        _combinedHash = initialCombinedHash; 
    }
 
    internal static int CombineHashCodes(int h1, int h2) { 
        return ((h1 << 5) + h1) ^ h2;
    } 

    internal static int CombineHashCodes(int h1, int h2, int h3) {
        return CombineHashCodes(CombineHashCodes(h1, h2), h3);
    } 

    internal static int CombineHashCodes(int h1, int h2, int h3, int h4) { 
        return CombineHashCodes(CombineHashCodes(h1, h2), CombineHashCodes(h3, h4)); 
    }
 
    internal static int CombineHashCodes(int h1, int h2, int h3, int h4, int h5) {
        return CombineHashCodes(CombineHashCodes(h1, h2, h3, h4), h5);
    }
 
    internal static string GetDirectoryHash(VirtualPath virtualDir) {
        HashCodeCombiner hashCodeCombiner = new HashCodeCombiner(); 
        hashCodeCombiner.AddDirectory(virtualDir.MapPathInternal()); 
        return hashCodeCombiner.CombinedHashString;
    } 

    internal void AddArray(string[] a) {
        if (a != null) {
            int n = a.Length; 
            for (int i = 0; i < n; i++) {
                AddObject(a[i]); 
            } 
        }
    } 

    internal void AddInt(int n) {
        _combinedHash = ((_combinedHash << 5) + _combinedHash) ^ n;
        Debug.Trace("HashCodeCombiner", "Adding " + n.ToString("x") + " --> " + _combinedHash.ToString("x")); 
    }
 
    internal void AddObject(int n) { 
        AddInt(n);
    } 

    internal void AddObject(byte b) {
        AddInt(b.GetHashCode());
    } 

    internal void AddObject(long l) { 
        AddInt(l.GetHashCode()); 
    }
 
    internal void AddObject(bool b) {
        AddInt(b.GetHashCode());
    }
 
    internal void AddObject(string s) {
        if (s != null) 
            AddInt(StringUtil.GetStringHashCode(s)); 
    }
 
    internal void AddObject(Type t) {
        if (t != null)
            AddObject(System.Web.UI.Util.GetAssemblyQualifiedTypeName(t));
    } 

    internal void AddObject(object o) { 
        if (o != null) 
            AddInt(o.GetHashCode());
    } 

    internal void AddCaseInsensitiveString(string s) {
        if (s != null)
            AddInt((StringComparer.InvariantCultureIgnoreCase).GetHashCode(s)); 
    }
 
    internal void AddDateTime(DateTime dt) { 
        Debug.Trace("HashCodeCombiner", "Ticks: " + dt.Ticks.ToString("x"));
        Debug.Trace("HashCodeCombiner", "Hashcode: " + dt.GetHashCode().ToString("x")); 
        AddInt(dt.GetHashCode());
    }

    private void AddFileSize(long fileSize) { 
        Debug.Trace("HashCodeCombiner", "file size: " + fileSize.ToString("x"));
        Debug.Trace("HashCodeCombiner", "Hashcode: " + fileSize.GetHashCode().ToString("x")); 
        AddInt(fileSize.GetHashCode()); 
    }
 
    internal void AddFile(string fileName) {
        Debug.Trace("HashCodeCombiner", "AddFile: " + fileName);
        if (!FileUtil.FileExists(fileName)) {
 
            // Review: Should we change the dependency model to take directory into account?
            if (FileUtil.DirectoryExists(fileName)) { 
                // Add as a directory dependency if it's a directory. 
                AddDirectory(fileName);
                return; 
            }

            Debug.Trace("HashCodeCombiner", "Could not find target " + fileName);
            return; 
        }
 
        AddExistingFile(fileName); 
    }
 
    // Same as AddFile, but only called for a file which is known to exist
    private void AddExistingFile(string fileName) {
        Debug.Trace("HashCodeCombiner", "AddExistingFile: " + fileName);
        Debug.Assert(FileUtil.FileExists(fileName)); 

        AddInt(StringUtil.GetStringHashCode(fileName)); 
        FileInfo file = new FileInfo(fileName); 
        AddDateTime(file.CreationTimeUtc);
        AddDateTime(file.LastWriteTimeUtc); 
        AddFileSize(file.Length);
    }

    internal void AddDirectory(string directoryName) { 

        DirectoryInfo directory = new DirectoryInfo(directoryName); 
        if (!directory.Exists) { 
            return;
        } 

        AddObject(directoryName);

        // Go through all the files in the directory 
        foreach (FileData fileData in FileEnumerator.Create(directoryName)) {
 
            if (fileData.IsDirectory) 
                AddDirectory(fileData.FullName);
            else 
                AddExistingFile(fileData.FullName);
        }

        AddDateTime(directory.CreationTimeUtc); 
        AddDateTime(directory.LastWriteTimeUtc);
    } 
 
    // Same as AddDirectory, but only look at files that don't have a culture
    internal void AddResourcesDirectory(string directoryName) { 

        DirectoryInfo directory = new DirectoryInfo(directoryName);
        if (!directory.Exists) {
            return; 
        }
 
        AddObject(directoryName); 

        // Go through all the files in the directory 
        foreach (FileData fileData in FileEnumerator.Create(directoryName)) {

            if (fileData.IsDirectory)
                AddResourcesDirectory(fileData.FullName); 
            else {
                // Ignore the file if it has a culture, since only neutral files 
                // need to re-trigger compilation (VSWhidbey 359029) 
                string fullPath = fileData.FullName;
                if (System.Web.UI.Util.GetCultureName(fullPath) == null) { 
                    AddExistingFile(fullPath);
                }
            }
        } 

        AddDateTime(directory.CreationTimeUtc); 
    } 

    internal long CombinedHash { get { return _combinedHash; } } 
    internal int CombinedHash32 { get { return _combinedHash.GetHashCode(); } }

    internal string CombinedHashString {
        get { 
            return _combinedHash.ToString("x", CultureInfo.InvariantCulture);
        } 
    } 
}
 

}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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HashCodeCombiner.cs source code in C# .NET

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