////////////////////////////////////////////////////////////////////////////////
//
//  Microsoft Research Singularity
//
//  Copyright (c) Microsoft Corporation.  All rights reserved.
//
//  File:   Services/CredentialsManager/Util.sg
//
//  Note:
//

using System;
using System.Collections;
using System.Diagnostics;
using Microsoft.Contracts;
using Microsoft.Singularity;
using Microsoft.Singularity.Channels;
using Microsoft.Singularity.Directory;
using Microsoft.Singularity.Io;
using Microsoft.SingSharp;

namespace Microsoft.Singularity.Security.CredentialsManager
{
    internal class Util
    {
        // These methods combine two or more hash codes to produce a combined hash.
        // The idea is that we multiply the values by different prime numbers
        // (while extending to 64 bits), XOR the results, and then fold the top 32 bits
        // into the bottom.  This is completely untested; I have no idea whether this
        // is a great or horrible way to combine hash values.
    
        public static int CombineHashCodes(int hc0, int hc1)
        {
            long hc = ((long)hc0) ^ (((long)hc1) * 3);
            return unchecked((int)(((hc >> 32) ^ (hc)) & 0xffffffffu));
        }
        
        public static int CombineHashCodes(int hc0, int hc1, int hc2)
        {
            long hc = ((long)hc0) ^ (((long)hc1) * 3) ^ (((long)hc2) * 5);
            return unchecked((int)(((hc >> 32) ^ (hc)) & 0xffffffffu));
        }
        
        public static int CombineHashCodes(int hc0, int hc1, int hc2, int hc3)
        {
            long hc = ((long)hc0) ^ (((long)hc1) * 3) ^ (((long)hc2) * 5) ^ (((long)hc3) * 7);
            return unchecked((int)(((hc >> 32) ^ (hc)) & 0xffffffffu));
        }
        
        public static string! ToStringDelete([Claims]char[]! in ExHeap exstring)
        {
            string! localstring = Bitter.ToString2(exstring);
            delete exstring;
            return localstring;
        }
        
        public static void DumpException(Exception! chain)
        {
            for (Exception ex = chain; ex != null; ex = ex.InnerException)
            {
                DebugStub.WriteLine(ex.GetType().FullName + ": " + ex.Message);
            }
        }
    }
}