///////////////////////////////////////////////////////////////////////////////
//
//  Microsoft Research Singularity
//
//  Copyright (c) Microsoft Corporation.  All rights reserved.
//
//  Note:   The SPECWeb99 web app
//

using FileSystem.Utils;
using Microsoft.Contracts;
using Microsoft.SingSharp.Reflection;
using Microsoft.SingSharp.Runtime;
using Microsoft.SingSharp;
using Microsoft.Singularity.Applications;
using Microsoft.Singularity.Channels;
using Microsoft.Singularity.Configuration;
using Microsoft.Singularity.Diagnostics.Contracts;
using Microsoft.Singularity.Directory;
using Microsoft.Singularity.Io;
using Microsoft.Singularity.V1.Services;
using Microsoft.Singularity.WebApps.Contracts;
using Microsoft.Singularity.WebApps;
using System.Collections;
using System.Diagnostics;
using System.Net.IP;
using System.Text;
using System.Threading;
using System.Web;
using System;

[assembly: Transform(typeof(WebAppResourceTransform))]

namespace Microsoft.Singularity.WebApps
{
    [Category("WebApp")]
    internal sealed class Parameters
    {
        [Endpoint]
        public readonly TRef<WebAppContract.Exp:Start> webAppRef;

        reflective private Parameters();
    }

    public class SPECWeb99WebApp : IWebApp
    {
        private const string ContentDir       = "/fs/specweb";
        private const string PostLogFile      = ContentDir + "/sing_dyn/postlog";
        private const string CustomAdsDir     = ContentDir + "/sing_dyn";
        private const string CustomAdsFile    = CustomAdsDir + "/Custom.Ads";
        private const string UserPersonalityDir  = ContentDir + "/sing_dyn";
        private const string UserPersonalityFile = UserPersonalityDir + "/User.Personality";

        private const string CookieHeaderName     = "Cookie";
        private const string CookiePushHeaderName = "Set-Cookie";

        private const uint GENDER_MASK    = 0x30000000;
        private const uint AGE_GROUP_MASK = 0x0f000000;
        private const uint REGION_MASK    = 0x00f00000;
        private const uint INTEREST1_MASK = 0x000ffc00;
        private const uint INTEREST2_MASK = 0x000003ff;

        private const int CustomAdsLines            = 360;
        private const int CustomAdsLineLength       = 39; // Including \n
        private const int CustomAdsFileBytes        = CustomAdsLines * CustomAdsLineLength;
        private const int UserPersonalityLines      = 360;
        private const int UserPersonalityLineLength = 15; // Including \n
        private const int UserPersonalityFileBytes  = UserPersonalityLines * UserPersonalityLineLength;

        private const long PostLogHeaderSize = 11; // Including \n
        private const long PostLogRecordSize = 139; // Including \n

        private const int SubstitutionPatternLength = 48; // <!WEB99CAD><IMG SRC="/file_set/dirNNNNN/classX_Y
        private const int SubstituteNum1Pos = 34;         // 0123456789012345678901234567890123^          ^ ^
        private const int SubstituteNum2Pos = 45;         // 012345678901234567890123456789012345678901234| |
        private const int SubstituteNum3Pos = 47;         // 01234567890123456789012345678901234567890123456|

        private byte[] HtmlPreamble1, HtmlPreamble2, HtmlPreamble3, HtmlPostamble;
        private byte[] PostLogInitData;
        private byte[] MatchPattern;

        private struct CustomAdsRecord
        { public uint demographics, weightings, minmatch, expiry; }

        private CachedFile! userPersonalityFile;
        private CachedFile! customAdsFile;
        private Parameters! config;

        // Used for TaskTimes.
        private ProcessData [] processData;
        private ProcessData [] processData2;
        private TimeSpan startTime;
        private TimeSpan endTime;
        private TRef<ProcessContract.Imp:ReadyState> processRef;


        private TRef<DirectoryServiceContract.Imp:Ready> epNS;

        // HACKHACK: to accelerate fetching from the filesystem, we pre-form a pool of
        // connections directly to the FS. But in order to do that, we need to know where
        // the filesystem is mounted. Currently, we hardcode that.
        private Queue! fsContractPool = new Queue(); // lock on the queue object for consistency
        private const string FSMountPoint = "/fs/";


        [NotDelayed]
        internal SPECWeb99WebApp(Parameters! config)
        {
            HtmlPreamble1 = Encoding.ASCII.GetBytes("<html>\n<head><title>SPECweb99 Dynamic GET & POST Test</title></head>\n<body>\n<p>SERVER_SOFTWARE = Singularity Cassini web server\n<p>REMOTE_ADDR = ");
            HtmlPreamble2 = Encoding.ASCII.GetBytes("\n<p>SCRIPT_NAME = SPECWeb99WebApp\n<p>QUERY_STRING = ");
            HtmlPreamble3 = Encoding.ASCII.GetBytes("\n<pre>\n");
            HtmlPostamble = Encoding.ASCII.GetBytes("\n</pre>\n</body></html>\n");

            PostLogInitData = Encoding.ASCII.GetBytes("         0\n");

            MatchPattern = Encoding.ASCII.GetBytes("<!WEB99CAD><IMG SRC=\"/file_set/dir");

            customAdsFile = new CachedFile(CustomAdsFile, CustomAdsFileBytes);
            userPersonalityFile  = new CachedFile(UserPersonalityFile, UserPersonalityFileBytes);
            this.config = config;

            base();
            assert PostLogInitData.Length == (int)PostLogHeaderSize;
            start = DateTime.Now;

            // Get a new directory service contract
            epNS = new TRef<DirectoryServiceContract.Imp:Ready>(DirectoryService.NewClientEndpoint());
            processRef = new TRef<ProcessContract.Imp:ReadyState>(GetProcessChannel());
        }

        private ProcessContract.Imp:ReadyState! GetProcessChannel()
        {
            DirectoryServiceContract.Imp:Ready nsImp = epNS.Acquire();
            try {
                ProcessContract.Imp! dsImp;
                ProcessContract.Exp! dsExp;
                ProcessContract.NewChannel(out dsImp, out dsExp);
                ErrorCode errorOut = ErrorCode.NoError;
                bool bound = SdsUtils.BindDSP(ProcessContract.ModuleName, nsImp, dsExp, out errorOut);

                if (!bound) {
                    delete dsImp;
                    throw new Exception("Failed to bind to filesystem prefix");
                }
                else {
                    dsImp.RecvReady();
                    return dsImp;
                }
            }
            finally {
                epNS.Release(nsImp);
            }
        }

        private void RecycleFSChannel([Claims] DirectoryServiceContract.Imp:Ready! dsImp)
        {
            lock (fsContractPool) {
                fsContractPool.Enqueue(new TRef<DirectoryServiceContract.Imp:Ready> (dsImp));
                Monitor.Pulse(fsContractPool);
            }
        }

        private DirectoryServiceContract.Imp:Ready! GetFSChannel()
        {
            ulong startCycles = Processor.CycleCount;
            ulong endCycles, ms;

            lock (fsContractPool) {
                endCycles = Processor.CycleCount;
                ms = ((endCycles - startCycles) * 1000ul) / (ulong)Processor.CyclesPerSecond;

                if (ms > 5) {
                    //DebugStub.WriteLine("Contention for file contracts queue: {0}",
                    //__arglist(ms));
                }

                if (fsContractPool.Count > 0) {
                    return ((TRef<DirectoryServiceContract.Imp:Ready>!)fsContractPool.Dequeue()).Acquire();
                }
            }

            // All FS channels are in use; make a new one
            startCycles = Processor.CycleCount;
            DirectoryServiceContract.Imp:Ready nsImp = epNS.Acquire();

            endCycles = Processor.CycleCount;
            ms = ((endCycles - startCycles) * 1000ul) / (ulong)Processor.CyclesPerSecond;

            if (ms > 5) {
                //DebugStub.WriteLine("Contention for master namespace contract: {0}",
                //__arglist(ms));
            }

            try {
                DirectoryServiceContract.Imp! dsImp;
                DirectoryServiceContract.Exp! dsExp;
                DirectoryServiceContract.NewChannel(out dsImp, out dsExp);
                ErrorCode errorOut = ErrorCode.NoError;
                bool bound = SdsUtils.BindDSP(FSMountPoint, nsImp, dsExp, out errorOut);

                if (!bound) {
                    delete dsImp;
                    throw new Exception("Failed to bind to filesystem prefix");
                }
                else {
                    dsImp.RecvSuccess();
                    return dsImp;
                }
            }
            finally {
                epNS.Release(nsImp);
            }
        }

        private FileContract.Imp OpenFile(string! filePath)
        {
            //
            // Take advantage of our cached FS connections for all requests
            // heading for the file system
            //
            if (filePath.IndexOf(FSMountPoint) == 0) {
                string suffix = filePath.Substring(FSMountPoint.Length,
                                                   filePath.Length - FSMountPoint.Length);

                DirectoryServiceContract.Imp:Ready! nsImp = GetFSChannel();

                try {
                    return FileUtils.OpenFile(suffix, nsImp);
                }
                finally {
                    RecycleFSChannel(nsImp);
                }
            }
            else {
                return FileUtils.OpenFile(filePath);
            }
        }

        DateTime start;
        bool isRecording = false;
        bool isDone = false;
        public void ProcessRequest(IHttpRequest! request)
        {

            //
            //TimeSpan beenRunning = DateTime.Now-start;
            //if (beenRunning.TotalSeconds > 300 && !isRecording && !isDone) {
            //  Console.WriteLine("\n\n\nRECORDING\n\n\n");
            //  isRecording = true;
            //  WebAppFSUtils.recording = true;
            //  FileUtils.recording = true;
            //}
            //else if (beenRunning.TotalSeconds > 330 && isRecording && !isDone) {
            //  Console.WriteLine("\n\n\nSTOP RECORDING\n\n\n");
            //  isDone = true;
            //  WebAppFSUtils.recording = false;
            //  FileUtils.recording = false;
            //  float bindTime = (float) FileUtils.bindTime.Ticks / TimeSpan.TicksPerSecond;
            //  float readTime = (float) WebAppFSUtils.readTime.Ticks / TimeSpan.TicksPerSecond;
            //  Console.WriteLine("Bind: count: "+FileUtils.bindCount+", time: "+bindTime+"\n"+
            //      "Read: count: "+WebAppFSUtils.readCount+", time: "+readTime);
            //}
            //

            string uri = request.GetUriPath();

            if ((uri == null) || (uri.Length == 0)) {
                uri = "/";
            }
            DebugStub.Print("Got Uri: {0}\n", __arglist(uri));
            if (uri == "/dynamic-content") {
                HandleDynamicRequest(request);
            }
            else {
                // Treat as a request for a static file

                if (uri.IndexOf(FSMountPoint) == 0) {
                    string suffix = uri.Substring(FSMountPoint.Length, uri.Length - FSMountPoint.Length);
                    // Serve using a FS contract from the pool
                    DirectoryServiceContract.Imp:Ready! nsImp = GetFSChannel(); // blocks

                    try {
                        WebAppFSUtils.ServeFSPath(suffix, request, nsImp);
                    }
                    finally {
                        RecycleFSChannel(nsImp);
                    }

                }
                else {
                    // Serve with the single, general-purpose directory service channel
                    DebugStub.Break(); // TODO remove me
                    DirectoryServiceContract.Imp:Ready! nsImp = epNS.Acquire(); // blocks

                    try {
                        WebAppFSUtils.ServeFSPath(uri, request, nsImp);
                    }
                    finally {
                        epNS.Release(nsImp);
                    }
                }
            }
        }

        ///////////////////////////////////////////////////////////////////////
        //
        // Helper code
        //
        private void WriteErrorResponse(IHttpRequest! request, int error, string! message)
        {
            switch (error) {
                case 400:
                    request.SendStatus(error, "Bad Request");
                    break;
                case 404:
                    request.SendStatus(error, "Not Found");
                    break;
                case 500:
                    request.SendStatus(error, "Internal Server Error");
                    break;
                default:
                    request.SendStatus(error, "Error");
                    break;
            }
            request.SendHeader("Content-type", "text/html");

            request.SendBodyData(HtmlPreamble1);
            request.SendBodyData(Encoding.ASCII.GetBytes(request.GetRemoteAddress()));
            request.SendBodyData(HtmlPreamble2);

            string queryString = request.GetQueryString();

            if (queryString != null) {
                request.SendBodyData(Encoding.ASCII.GetBytes(queryString));
            }
            else {
                request.SendBodyData(Encoding.ASCII.GetBytes("<no query string supplied>"));
            }

            request.SendBodyData(HtmlPreamble3);

            if ((message != null) && (message.Length > 0)) {
                request.SendBodyData(Encoding.ASCII.GetBytes(message));
            }
            WriteResponseHtmlPostamble(request);
        }

        private void WriteResponseHtmlPreamble(IHttpRequest! request)
        {
            request.SendStatus(200, "OK");
            request.SendHeader("Content-type", "text/html");

            request.SendBodyData(HtmlPreamble1);
            request.SendBodyData(Encoding.ASCII.GetBytes(request.GetRemoteAddress()));
            request.SendBodyData(HtmlPreamble2);

            string queryString = request.GetQueryString();

            if (queryString != null) {
                request.SendBodyData(Encoding.ASCII.GetBytes(queryString));
            }
            else {
                request.SendBodyData(Encoding.ASCII.GetBytes("<no query string supplied>"));
            }

            request.SendBodyData(HtmlPreamble3);
        }

        private void WriteResponseHtmlPostamble(IHttpRequest! request)
        {
            request.SendBodyData(HtmlPostamble);
        }

        private void WriteMessageResponse(IHttpRequest! request, string! message)
        {
            WriteResponseHtmlPreamble(request);

            if ((message != null) && (message.Length > 0)) {
                request.SendBodyData(Encoding.ASCII.GetBytes(message));
            }

            WriteResponseHtmlPostamble(request);
        }

        private void WriteFileResponse(IHttpRequest! request, string! filePath)
        {
            FileContract.Imp fileImp = OpenFile(filePath);

            if (fileImp != null) {
                WriteFileResponse(request, fileImp);
                delete fileImp;
            }
            else {
                WriteErrorResponse(request, 404, "Couldn't open file: " + filePath);
            }
        }

        private void WriteFileResponse(IHttpRequest! request, FileContract.Imp! fileImp)
        {
            WriteResponseHtmlPreamble(request);
            WebAppFSUtils.TransmitFileContents(fileImp, request);
            WriteResponseHtmlPostamble(request);
        }

        private void HandleDynamicRequest(IHttpRequest! request)
        {
            string verb = request.GetVerb();

            if (verb == "GET") {
                HandleGET(request);
            }
            else if (verb == "POST") {
                HandlePOST(request);
            }
            else {
                WriteErrorResponse(request, 400, "Unknown HTTP verb: " + verb);
            }

            request.Done();
        }

        private bool ParseCookie(string! cookie, out uint myUser, out uint lastAd,
                                 out string rejectString)
        {
            const string cookiePreamble = "my_cookie=user_id=";
            const string lastAdPreamble = "last_ad=";

            rejectString = null;
            myUser = 0;
            lastAd = 0;

            if (!cookie.StartsWith(cookiePreamble)) {
                rejectString = "Invalid cookie format (bad preamble): \"" + cookie + "\"";
                return false;
            }

            int nextAmp = cookie.IndexOf('&', cookiePreamble.Length);

            if (nextAmp == -1) {
                rejectString = "Invalid cookie format (no ampersand): \"" + cookie + "\"";
                return false;
            }

            string myUserStr = cookie.Substring(cookiePreamble.Length, nextAmp - cookiePreamble.Length);

            try {
                myUser = UInt32.Parse(myUserStr);
            }
            catch (Exception) {
                rejectString = "Invalid cookie format (bad user_id value): \"" + cookie + "\"";
                return false;
            }

            string remainderStr = cookie.Substring(nextAmp + 1);

            if (!remainderStr.StartsWith(lastAdPreamble)) {
                rejectString = "Invalid cookie format (no last_ad field): \"" + cookie + "\"";
                return false;
            }

            try {
                lastAd = UInt32.Parse(remainderStr.Substring(lastAdPreamble.Length));
            }
            catch (Exception) {
                rejectString = "Invalid cookie format (bad last_ad value): \"" + cookie + "\"";
                return false;
            }

            return true;
        }

        private uint Get1970Time()
        {
            TimeSpan delta1970 = DateTime.Now - new DateTime(1970, 1, 1);
            return (uint)delta1970.TotalSeconds;
        }

        ///////////////////////////////////////////////////////////////////////
        //
        // Dynamic GET
        //

        private void HandleGET(IHttpRequest! request)
        {
            const string commandPrefix = "command/";
            string queryString = request.GetQueryString();

            if ((queryString != null) && (queryString.Length > 0)) {
                if (queryString.StartsWith(commandPrefix)) {
                    HandleCommand(request, queryString.Substring(commandPrefix.Length));
                }
                else {
                    // We must serve the file corresponding to
                    // the queryString. We may or may not have to
                    // perform substitution, depending on whether
                    // a cookie is provided.
                    string filePath = String.Format("{0}{1}", ContentDir, queryString);
                    string cookie = request.GetHeader(CookieHeaderName);

                    if ((cookie == null) || (cookie.Length == 0)) {
                        // Just serve the file normally
                        WriteFileResponse(request, filePath);
                    }
                    else {
                        HandleSubstitution(request, filePath, cookie);
                    }
                }
            }
            else {
                WriteErrorResponse(request, 400,
                                   "A query string is required with a GET operation");
            }
        }

        ///////////////////////////////////////////////////////////////////////
        //
        // Housekeeping commands
        //

        // Validate string only contains integers
        private static string CheckDigits(string s)
        {
            if (s == null) return null;
            for (int i = 0; i < s.Length; i++) {
                if (s[i] < '0' || s[i] > '9') {
                    return null;
                }
            }
            return s;
        }

        private bool RunCommand(string[]! commandLine, StringBuilder! output)
        {
            try {
                // Load the manifest for the given command
                DirectoryServiceContract.Imp ds = epNS.Acquire();
                Manifest manifest = Binder.LoadManifest(ds, commandLine[0]);
                epNS.Release(ds);

                if (manifest == null) {
                    return false; // bad command
                }

                Process process;

                if (manifest.HasParameters()) {
                    ParameterProcessor processor = new ParameterProcessor();
                    string action;

                    if (!processor.ProcessParameters(commandLine,
                                                     manifest, out process, out action)) {
                        // bad command line
                        return false;
                    }

                    if (manifest.SetEndpoints(process, action, false) < 0) {
                        // couldn't prepare service endpoints
                        return false;
                    }
                }
                else {
                    process = new Process(commandLine, null, 2);
                }

                if (process == null) {
                    // Failed to create the process object
                    return false;
                }

                // Feed the process do-nothing input and output pipes
                UnicodePipeContract.Imp! stdInImp, stdOutImp;
                UnicodePipeContract.Exp! stdInExp, stdOutExp;

                UnicodePipeContract.NewChannel(out stdInImp, out stdInExp);
                UnicodePipeContract.NewChannel(out stdOutImp, out stdOutExp);

                process.SetStartupEndpoint(0, (Endpoint * in ExHeap) stdInExp);
                process.SetStartupEndpoint(1, (Endpoint * in ExHeap) stdOutImp);

                process.Start();

                // Capture the process output (this also prevents the child
                // from hanging trying to write to the console)
                bool stillAlive = true;

                while (stillAlive) {
                    switch receive {
                        case stdOutExp.Write(char[]! in ExHeap buffer, offset, count) :
                            output.Append(Bitter.ToString2(buffer, offset, count));
                            stdOutExp.SendAckWrite(buffer);
                            break;

                        case unsatisfiable:
                            stillAlive = false;
                            break;
                    }
                }

                process.Join();
                process.Dispose(true);

                delete stdInImp;
                delete stdOutExp;

                return true;
            }
            catch (ProcessCreateException) {
                return false;
            }
        }

        private void HandleReset(IHttpRequest! request, string[]! arguments)
        {
            string maxLoad    = null;
            string pointTime  = null;
            string maxThreads = null;
            string expired1   = null;
            string expired2   = null;
            string urlRoot    = null;

            for (int i = 0; i < arguments.Length; i++) {
                int remain =  arguments.Length - i - 1;

                // All values are key-value, except expiry list which
                // has two values.  If there's not at least one argument
                // it's a bogus request.
                if (remain == 0)
                    break;

                if (arguments[i] == "maxload") {
                    maxLoad = CheckDigits(arguments[++i]);
                    if (maxLoad == null) {
                        WriteErrorResponse(request, 400, "Bad 'maxload' element in GET request");
                        return;
                    }
                }
                else if (arguments[i] == "pttime") {
                    pointTime = CheckDigits(arguments[++i]);
                    if (pointTime == null) {
                        WriteErrorResponse(request, 400, "Bad 'pttime' in element GET request");
                        return;
                    }
                }
                else if (arguments[i] == "maxthread") {
                    maxThreads = CheckDigits(arguments[++i]);
                    if (maxThreads == null) {
                        WriteErrorResponse(request, 400, "Bad 'maxthread' in element GET request");
                        return;
                    }
                }
                else if (arguments[i] == "exp") {
                    if (remain < 2) {
                        WriteErrorResponse(request, 400, "Bad 'expired_list' element in GET request");
                        return;
                    }
                    expired1 = CheckDigits(arguments[++i]);
                    if (expired1 == null) {
                        WriteErrorResponse(request, 400, "Bad 'expired_list[0]' element in GET request");
                        return;
                    }
                    expired2 = CheckDigits(arguments[++i]);
                    if (expired2 == null) {
                        WriteErrorResponse(request, 400, "Bad 'expired_list[1]' element in GET request");
                        return;
                    }
                }
                else if (arguments[i] == "urlroot") {
                    urlRoot = arguments[++i];
                }
            }

            if (maxLoad == null) {
                WriteErrorResponse(request, 400, "Missing 'maxload' element in GET request.");
                return;
            }
            else if (pointTime == null) {
                WriteErrorResponse(request, 400, "Missing 'pttime' element in GET  request.");
                return;
            }
            else if (maxThreads == null) {
                WriteErrorResponse(request, 400, "Missing 'maxthreads' element in GET request.");
                return;
            }
            else if ((expired1 == null) || (expired2 == null)) {
                WriteErrorResponse(request, 400, "Missing 'expired_list' element in GET request.");
                return;
            }
            else if (urlRoot == null) {
                WriteErrorResponse(request, 400, "Missing 'url_root' element in GET request.");
                return;
            }

            // These are allowed to fail
            DirectoryUtils.CreateDirectory(CustomAdsDir);
            FileUtils.DeleteFile(CustomAdsFile);

            string []! cadgen = new string[] { "cadgen99",
                                               "-d=" + CustomAdsDir,
                                               "-e=" + pointTime,
                                               "-t=" + maxThreads,
                                               "-exp1=" + expired1,
                                               "-exp2=" + expired2};

            StringBuilder capturedOutput = new StringBuilder();

            if (RunCommand(cadgen, capturedOutput) == false) {
                WriteErrorResponse(request, 500, "Failed to run cadgen:\n\n" +
                                   capturedOutput.ToString());
                return;
            }

            if (!customAdsFile.Refresh()) {
                WriteErrorResponse(request, 500, "Failed to load ads file");
                return;
            }

            if (((!)customAdsFile.FileData).Length < CustomAdsFileBytes) {
                WriteErrorResponse(request, 500, "Custom ads file was too small after generation");
                return;
            }

            // It's OK for these to fail
            DirectoryUtils.CreateDirectory(UserPersonalityDir);
            FileUtils.DeleteFile(UserPersonalityFile);

            string []! upfgen = new string[] {"/init/upfgen99",
                                              "-c=" + UserPersonalityDir,
                                              "-n=" + maxLoad,
                                              "-t=" + maxThreads};

            capturedOutput = new StringBuilder();

            if (RunCommand(upfgen, capturedOutput) == false) {
                WriteErrorResponse(request, 500, "Failed to run upfgen:\n\n" +
                                   capturedOutput.ToString());
                return;
            }

            if (!userPersonalityFile.Refresh()) {
                WriteErrorResponse(request, 500, "Failed to load user personality file");
                return;
            }

            if (!ResetPostLog()) {
                WriteErrorResponse(request, 500, "Failed to reset the PostLog file");
                return;
            }

            // Signal success with a blank message page
            WriteMessageResponse(request, "");

            // As the last part of reset, we set up the performance counters.

            DebugStub.WriteLine("SPECweb99: Started Benchmark");

            ProcessContract.Imp imp = processRef.Acquire();
            this.processData = GetProcessData(imp);
            processRef.Release(imp);
            startTime =  ProcessService.GetUpTime();

#if CAPTURE_PERFORMANCE_COUNTERS
            for (uint u = 0; u < 16; u++) {
                DebugStub.WritePerfCounter(0, 0);
            }

            if (IsAmd()) {
                for (uint pmc = 0; pmc < 4; pmc++) {
                    Processor.WriteMsr(0xc0010004 + pmc, 0);
                }
            }
            DebugStub.WritePerfCounter(7, Processor.GetCycleCount());
#endif
        }

        private static bool IsAmd()
        {
            uint eax;
            uint ebx;
            uint ecx;
            uint edx;
            Processor.ReadCpuid(0, out eax, out ebx, out ecx, out edx);
            return (ebx == 0x68747541 && ecx == 0x444d4163 && edx == 0x69746e65);
        }

        private static void MyWrite(IHttpRequest! request, string! msg, params Object[]! args)
        {
            String text = String.Format(msg, args);
            request.SendBodyData(Encoding.ASCII.GetBytes(text));
        }

        private void HandleFinish(IHttpRequest! request, string[]! arguments)
        {
            request.SendStatus(200, "OK");
            request.SendHeader("Content-type", "text/plain");

#if CAPTURE_PERFORMANCE_COUNTERS
            // Read the AMD and Singularity performance counters.
            ulong b0 = 0;
            ulong t0 = 0;
            ulong e0 = 0;
            ulong e1 = 0;
            ulong e2 = 0;
            ulong e3 = 0;
            ulong p0 = 0;
            ulong p1 = 0;
            ulong p2 = 0;
            ulong p3 = 0;
            ulong z0 = 0;
            ulong z1 = 0;
            ulong z2 = 0;
            ulong z3 = 0;
            ulong z4 = 0;
            ulong z5 = 0;
            ulong z6 = 0;
            ulong z8 = 0;
            ulong z9 = 0;
            ulong z10 = 0;
            ulong z11 = 0;
            ulong z12 = 0;
            ulong z13 = 0;
            ulong z14 = 0;
            ulong z15 = 0;
            if (IsAmd()) {
                b0 = DebugStub.ReadPerfCounter(7);
                t0 = Processor.GetCycleCount();
                e0 = Processor.ReadMsr(0xc0010000);
                e1 = Processor.ReadMsr(0xc0010001);
                e2 = Processor.ReadMsr(0xc0010002);
                e3 = Processor.ReadMsr(0xc0010003);
                p0 = Processor.ReadPmc(0);
                p1 = Processor.ReadPmc(1);
                p2 = Processor.ReadPmc(2);
                p3 = Processor.ReadPmc(3);
            }
            else {
                b0 = DebugStub.ReadPerfCounter(7);
                t0 = Processor.GetCycleCount();
            }
            z0 = DebugStub.ReadPerfCounter(0);
            z1 = DebugStub.ReadPerfCounter(1);
            z2 = DebugStub.ReadPerfCounter(2);
            z3 = DebugStub.ReadPerfCounter(3);
            z4 = DebugStub.ReadPerfCounter(4);
            z5 = DebugStub.ReadPerfCounter(5);
            z6 = DebugStub.ReadPerfCounter(6);
            z8 = DebugStub.ReadPerfCounter(8);
            z9 = DebugStub.ReadPerfCounter(9);
            z10 = DebugStub.ReadPerfCounter(10);
            z11 = DebugStub.ReadPerfCounter(11);
            z12 = DebugStub.ReadPerfCounter(12);
            z13 = DebugStub.ReadPerfCounter(13);
            z14 = DebugStub.ReadPerfCounter(14);
            z15 = DebugStub.ReadPerfCounter(15);

            endTime =  ProcessService.GetUpTime();
            ProcessContract.Imp imp = processRef.Acquire();
            processData2 = GetProcessData(imp);
            processRef.Release(imp);


            t0 = t0 - b0;
            z5 += z8 + z9 + z10 + z11 + z12 + z13;

            ulong n0 = t0;
            if ((e0 & 0xff) == PerfEvtSel.CyclesNotHalted) {
                n0 = p0;
            }
            else if ((e1 & 0xff) == PerfEvtSel.CyclesNotHalted) {
                n0 = p1;
            }
            else if ((e2 & 0xff) == PerfEvtSel.CyclesNotHalted) {
                n0 = p2;
            }
            else if ((e3 & 0xff) == PerfEvtSel.CyclesNotHalted) {
                n0 = p3;
            }

            MyWrite(request, "{0,20}: {1,16}  {2,16}\n", "Cycles", t0, n0);
            MyWrite(request, "{0,20}: {1,16:f3}% {2,16:f3}%\n",
                    PerfEvtSel.ToString(e0),
                    (p0 * 100.0) / t0,
                    (p0 * 100.0) / n0);
            MyWrite(request, "{0,20}: {1,16:f3}% {2,16:f3}%\n",
                    PerfEvtSel.ToString(e1),
                    (p1 * 100.0) / t0,
                    (p1 * 100.0) / n0);
            MyWrite(request, "{0,20}: {1,16:f3}% {2,16:f3}%\n",
                    PerfEvtSel.ToString(e2),
                    (p2 * 100.0) / t0,
                    (p2 * 100.0) / n0);
            MyWrite(request, "{0,20}: {1,16:f3}% {2,16:f3}%\n",
                    PerfEvtSel.ToString(e3),
                    (p3 * 100.0) / t0,
                    (p3 * 100.0) / n0);
            MyWrite(request, "{0,20}: {1,16:f3}% {2,16:f3}%\n",
                    "App GC",
                    (z5 * 100.0) / t0,
                    (z5 * 100.0) / n0);
            MyWrite(request, "{0,20}: {1,16:f3}% {2,16:f3}%\n",
                    "SpecWeb GC",
                    (z8 * 100.0) / t0,
                    (z8 * 100.0) / n0);
            MyWrite(request, "{0,20}: {1,16:f3}% {2,16:f3}%\n",
                    "Cassini GC",
                    (z9 * 100.0) / t0,
                    (z9 * 100.0) / n0);
            MyWrite(request, "{0,20}: {1,16:f3}% {2,16:f3}%\n",
                    "NetStack GC",
                    (z10 * 100.0) / t0,
                    (z10 * 100.0) / n0);
            MyWrite(request, "{0,20}: {1,16:f3}% {2,16:f3}%\n",
                    "NIC GC",
                    (z11 * 100.0) / t0,
                    (z11 * 100.0) / n0);
            MyWrite(request, "{0,20}: {1,16:f3}% {2,16:f3}%\n",
                    "FS GC",
                    (z12 * 100.0) / t0,
                    (z12 * 100.0) / n0);
            MyWrite(request, "{0,20}: {1,16:f3}% {2,16:f3}%\n",
                    "Disk GC",
                    (z13 * 100.0) / t0,
                    (z13 * 100.0) / n0);
            MyWrite(request, "{0,20}: {1,16:f3}% {2,16:f3}%\n",
                    "Kernel GC",
                    (z6 * 100.0) / t0,
                    (z6 * 100.0) / n0);
            MyWrite(request, "{0,20}: {1,16}\n", "FAT Found", z0);
            MyWrite(request, "{0,20}: {1,16}\n", "FAT In Use", z1);
            MyWrite(request, "{0,20}: {1,16}\n", "FAT Miss Free", z2);
            MyWrite(request, "{0,20}: {1,16}\n", "FAT Miss Evict", z3);
            MyWrite(request, "{0,20}: {1,16}\n", "Threads", z4);
            MyWrite(request, "{0,20}: {1,16}\n", "PerfCounter 14", z14);
            MyWrite(request, "{0,20}: {1,16}\n", "PerfCounter 15", z15);

            if (!IsAmd()) {
                MyWrite(request, "Intel processor, PMC values will be zero.\n");
            }
#endif

            // Prep for display
            if (this.processData != null) {
                Hashtable processName = new Hashtable(processData.Length);
                for (int i = 0; i < processData.Length; i++) {
                    ProcessData pd = processData[i];
                    if (pd == null) {
                        continue;
                    }
                    processName.Add(pd.id, pd);
                }

                // Display the results
                double actualSpan =  (double) ((endTime - startTime).TotalMilliseconds);
                MyWrite(request, "\n");
                MyWrite(request, "PID Task Name            total(ms) % tot\n");
                MyWrite(request, "=== =================== ========== =====\n");
                double totalPercent = 0;
                //long  durationMs =  monitorSeconds*1000;
                double  durationMs =  actualSpan;
                double totalTime;
                double deltaTotal;
                string pattern = "###,##0.00";
                string percentPattern = "#0.00";

                if (processData2 != null) {
                    for (int i = 0; i < processData2.Length; i++) {
                        ProcessData pd2 = processData2[i];
                        if (pd2 == null) {
                            continue;
                        }

                        totalTime = (double)pd2.totalTime;

                        double percent = 0;
                        ProcessData p = (ProcessData) processName[pd2.id];
                        if (p != null) {
                            if (p.name == pd2.name) {
                                totalTime -= p.totalTime;
                            }
                        }

                        totalTime /= DateTime.TicksPerMillisecond;

                        percent = durationMs == 0 ? 0 : (double) (totalTime / durationMs)  * 100 ;

                        //percent of time of this process spent in GC
                        if (totalTime > 0) {
                            MyWrite(request, "{0,3} {1,-19} {2,10} {3,5}\n",
                                    pd2.id,
                                    pd2.name,
                                    totalTime.ToString(pattern),
                                    percent.ToString(percentPattern));
                            totalPercent += percent;
                        }
                    }
                }

                MyWrite(request, "                                              ======\n");
                MyWrite(request, "                                               {0,5} accounted for\n",
                        totalPercent.ToString("00.00"));
                DebugStub.WriteLine("SPECweb99: Finished Benchmark");
            }
            else {
                DebugStub.Print("HandleTerminate found null processData\n");
            }
        }

        private void HandleCommand(IHttpRequest! request, string! command)
        {
            if (command == "Fetch") {
                // Lock on this to protect the PostLog
                lock (this) {
                    FileContract.Imp fileImp = OpenFile(PostLogFile);

                    if (fileImp != null) {
                        WriteFileResponse(request, fileImp);
                        delete fileImp;
                    }
                    else {
                        WriteErrorResponse(request, 404, "Error opening PostLog file");
                    }
                }
            }
            else if (command.StartsWith("Reset&")) {
                HandleReset(request,
                            command.Split(new char [] { '&', '=', ',' }));
            }
            else if (command.StartsWith("Finish")) {
                HandleFinish(request,
                             command.Split(new char [] { '&', '=', ',' }));
            }
        }

        ///////////////////////////////////////////////////////////////////////
        //
        // Dynamic POST support
        //

        private void HandlePOST(IHttpRequest! request)
        {
            string cookie = request.GetHeader(CookieHeaderName);

            if ((cookie == null) || (cookie.Length == 0)) {
                WriteErrorResponse(request, 400, "POST requires a 'Cookie' header");
                return;
            }

            byte[] bodyData = request.GetBodyData();

            if ((bodyData == null) || (bodyData.Length == 0)) {
                WriteErrorResponse(request, 400, "POST requires body data");
                return;
            }

            //
            // Parse the POST data
            //
            string urlRoot = null;
            int dirNum = -1, classNum = -1, fileNum = -1, clientNum = -1;
            string body = Encoding.ASCII.GetString(bodyData);
            string[] fragments = body.Split(new char[] { '=', '&' } );

            for (int i = 0; i < fragments.Length; i += 2) {
                if (fragments[i] == "urlroot") {
                    urlRoot = fragments[i + 1];
                }
                else if (fragments[i] == "dir") {
                    try {
                        dirNum = Int32.Parse(fragments[i + 1]);
                    }
                    catch (Exception) {
                        WriteErrorResponse(request, 400, "Bad 'dir' element in POST data");
                        return;
                    }
                }
                else if (fragments[i] == "class") {
                    try {
                        classNum = Int32.Parse(fragments[i + 1]);
                    }
                    catch (Exception) {
                        WriteErrorResponse(request, 400, "Bad 'class' element in POST data");
                        return;
                    }
                }
                else if (fragments[i] == "num") {
                    try {
                        fileNum = Int32.Parse(fragments[i + 1]);
                    }
                    catch (Exception) {
                        WriteErrorResponse(request, 400, "Bad 'num' element in POST data");
                        return;
                    }

                }
                else if (fragments[i] == "client") {
                    try {
                        clientNum = Int32.Parse(fragments[i + 1]);
                    }
                    catch (Exception) {
                        WriteErrorResponse(request, 400, "Bad 'client' element in POST data");
                        return;
                    }
                }
                else {
                    WriteErrorResponse(request, 400, "Invalid POST data item \"" + fragments[i] + "\"");
                    return;
                }
            }

            if (urlRoot == null) {
                WriteErrorResponse(request, 400, "Missing 'urlroot' item in POST data");
                return;
            }
            else if (dirNum == -1) {
                WriteErrorResponse(request, 400, "Missing 'dir' item in POST data");
                return;
            }
            else if (classNum == -1) {
                WriteErrorResponse(request, 400, "Missing 'class' item in POST data");
                return;
            }
            else if (fileNum == -1) {
                WriteErrorResponse(request, 400, "Missing 'num' item in POST data");
                return;
            }
            else if (clientNum == -1) {
                WriteErrorResponse(request, 400, "Missing 'client' item in POST data");
                return;
            }

            //
            // Parse the cookie data
            //
            string cookieReject;
            uint myCookie, lastAd;

            if (!ParseCookie(cookie, out myCookie, out lastAd, out cookieReject)) {
                WriteErrorResponse(request, 400, (!)cookieReject);
                return;
            }

            string filePath = String.Format("{0}{1}dir{2}/class{3}_{4}", ContentDir, urlRoot,
                                            dirNum.ToString("d05"), classNum, fileNum);

            // Write out all the parsed data
            if (!AppendToPostLog((uint)dirNum, (uint)classNum, (uint)fileNum,
                                 (uint)clientNum, filePath, (uint)myCookie)) {
                WriteErrorResponse(request, 400, "Error writing to PostLog file");
                return;
            }

            FileContract.Imp fileImp = OpenFile(filePath);

            if (fileImp != null) {
                request.SendHeader(CookiePushHeaderName, "my_cookie=" + myCookie.ToString());
                WriteFileResponse(request, fileImp);
                delete fileImp;
            }
            else {
                WriteErrorResponse(request, 404, "Couldn't open file: \"" + filePath + "\"");
                return;
            }
        }

        private bool ResetPostLog()
        {
            lock (this) {
                // OK to ignore the result of this; the file
                // may not exist.
                FileUtils.DeleteFile(PostLogFile);

                if (FileUtils.CreateFile(PostLogFile) != 0) {
                    return false;
                }

                FileContract.Imp fileImp = OpenFile(PostLogFile);

                if (fileImp == null) {
                    return false;
                }

                try {
                    long written = FileUtils.Write(fileImp, 0, PostLogInitData);

                    if (written < PostLogInitData.Length) {
                        return false;
                    }
                }
                finally {
                    delete fileImp;
                }
            }

            return true;
        }

        private bool AppendToPostLog(uint dirNum, uint classNum, uint fileNum,
                                     uint clientNum, string fileName, uint cookieNum)
        {
            lock (this) {
                FileContract.Imp fileImp = OpenFile(PostLogFile);

                if (fileImp == null) {
                    return false;
                }

                try {
                    // First, read in the header so we can increment the record count
                    byte[] header = new byte[PostLogHeaderSize];
                    if (FileUtils.Read(fileImp, 0,PostLogHeaderSize , 0, header) != PostLogHeaderSize) {
                        return false;
                    }

                    int numExistingRecords;

                    try {
                        numExistingRecords = Int32.Parse(
                            Encoding.ASCII.GetString(header, 0, PostLogHeaderSize - 1));
                    }
                    catch (Exception) {
                        return false;
                    }

                    // Increment the record count and rewrite the header
                    string newHeaderStr = String.Format("{0,10}\n", numExistingRecords + 1);
                    byte[] newHeader = Encoding.ASCII.GetBytes(newHeaderStr);
                    assert newHeader.Length == (int)PostLogHeaderSize;

                    if (FileUtils.Write(fileImp, 0, newHeader) != PostLogHeaderSize) {
                        return false;
                    }

                    // Write a new record to the appropriate offset in the file
                    long newRecordOffset = (numExistingRecords * PostLogRecordSize) + PostLogHeaderSize;
                    string newEntryStr = String.Format(
                        "{0,10} {1,10} {2,10} {3,5} {4,2} {5,2} {6,10} {7,-60} {8,10} {9,10}\n",
                        numExistingRecords + 1, Get1970Time(), ProcessService.GetCurrentProcessId(),
                        dirNum, classNum, fileNum, clientNum, fileName, ProcessService.GetCurrentProcessId(),
                        cookieNum);

                    byte[] newEntry = Encoding.ASCII.GetBytes(newEntryStr);
                    assert newEntry.Length == (int)PostLogRecordSize;

                    if (FileUtils.Write(fileImp, newRecordOffset, newEntry) != PostLogRecordSize) {
                        return false;
                    }
                }
                finally {
                    delete fileImp;
                }
            }

            return true;
        }

        ///////////////////////////////////////////////////////////////////////
        //
        // Substitution / ad-rotation support
        //

        private void SubstituteAt(byte[]! in ExHeap buffer, int offset, uint adId)
        {
            assert offset + SubstitutionPatternLength <= buffer.Length;
            string! num1 = (!)(adId / 36).ToString("d05");
            string! num2 = (!)((adId % 36) / 9).ToString();
            string! num3 = (!)(adId % 9).ToString();

            for (int i = 0; i < 5; i++) {
                buffer[offset + SubstituteNum1Pos + i] = (byte)num1[i];
            }

            buffer[offset + SubstituteNum2Pos] = (byte)num2[0]; // should be a single char
            buffer[offset + SubstituteNum3Pos] = (byte)num3[0]; // ditto
        }

        private int SubstituteInBlock(byte[]! in ExHeap buffer, uint maxBytes, uint adId)
        {
            // NOTE: the idea here is to find the randomly placed
            // markers in the file block and doctor them. The only
            // difficulty arises if there is a match of the prefix
            // of our search pattern at the end of a block (that is,
            // the pattern to match straddles a block boundary).
            // As a naive solution to this, if we detect such a case, we
            // return an amount to step back in the file so the next block
            // will contain the entire match-pattern. If we were smarter
            // we could keep state between invocations, instead.
            int startMatch = 0;
            int matchDepth = 0;
            int matchPatternLength = MatchPattern.Length;

            // Make this unsafe to skip the insane overhead of non-hoisted
            // ExHeap vector accesses
            unsafe {
                byte *pSrc = &buffer[0];
                fixed (byte *pMatch = &MatchPattern[0]) {
                    while (startMatch < maxBytes) {
                        if (pSrc[startMatch] == pMatch[0]) {
                            do {
                                ++matchDepth;

                                if (matchDepth == matchPatternLength) {
                                    // Found a match!
                                    SubstituteAt(buffer, startMatch, adId);
                                }

                                if (startMatch + matchDepth >= maxBytes) {
                                    // We were in the middle of a match
                                    // but hit the end of the buffer.
                                    // Step back by one disk sector
                                    return 512;
                                }
                            } while (pSrc[startMatch + matchDepth] == pMatch[matchDepth]);

                            startMatch += matchDepth;
                            matchDepth = 0;
                        }
                        else {
                            startMatch++;
                        }
                    }
                }
            }

            return 0;
        }

        private void WriteSubstitutedFile(IHttpRequest! request,
                                          string! filePath, uint adId)
        {
            FileContract.Imp fileImp = OpenFile(filePath);

            if (fileImp == null) {
                WriteErrorResponse(request, 404, "Couldn't open file " + filePath);
                return;
            }

            WriteResponseHtmlPreamble(request);

            try {
                long readSize = 1024 * 16; // 16KB
                long readOffset = 0;
                bool keepReading = true;

                do {
                    byte[] in ExHeap buf = new[ExHeap] byte[readSize];
                    fileImp.SendRead(buf, 0, readOffset, readSize);

                    switch receive {
                        case fileImp.AckRead( _buf, long bytesRead, int error) :
                            if ((error != 0) || (_buf == null)) {
                                if (_buf != null) {
                                    delete _buf;
                                }

                                keepReading = false;
                            }
                            else {
                                byte[]! in ExHeap original = _buf;
                                bool atEnd = (bytesRead < readSize);

                                if (bytesRead > 0) {
                                    int stepBack = SubstituteInBlock(original, (uint)bytesRead, adId);

                                    // Ignore any partial matches that occur at the very
                                    // end of the file
                                    if (atEnd) {
                                        stepBack = 0;
                                    }

                                    if ((stepBack > 0) || (bytesRead < readSize)) {
                                        // Discard the excess portion of the block
                                        delete
                                            Bitter.SplitOff(
                                                ref original,
                                                (int)(bytesRead - stepBack)
                                                );
                                    }

                                    request.SendBodyData(original);
                                    readOffset += (bytesRead - stepBack);
                                }
                                else {
                                    // By coincidence, our previous read took us to
                                    // exactly the end of the file. We should
                                    // optimize this away somehow
                                    delete original;
                                }

                                keepReading = !atEnd;
                            }
                            break;

                        case fileImp.ChannelClosed() :
                            keepReading = false;
                            break;
                    }
                } while (keepReading);
            }
            finally {
                delete fileImp;
            }

            WriteResponseHtmlPostamble(request);
        }


        private bool RetrieveAdData(uint adIndex, out uint demographics,
                                    out uint weightings, out uint minMatch,
                                    out uint expiry)
        {
            demographics = weightings = minMatch = expiry = 0;

            byte[] fileData = customAdsFile.FileData;

            if (fileData == null) {
                DebugStub.Break();
                return false;
            }

            if (fileData.Length < CustomAdsFileBytes) {
                DebugStub.Break();
                return false;
            }

            try {
                int startLine = (int)adIndex * (int)CustomAdsLineLength;

                // debug!
                string wholeLine = Encoding.ASCII.GetString(fileData, startLine, CustomAdsLineLength);

                if (wholeLine == null) {
                    DebugStub.Break();
                }

                string demoStr = Encoding.ASCII.GetString(fileData, startLine + 6, 8);
                string weightStr = Encoding.ASCII.GetString(fileData, startLine + 15, 8);
                string minMatchStr = Encoding.ASCII.GetString(fileData, startLine + 24, 3);
                string expiryStr = Encoding.ASCII.GetString(fileData, startLine + 28, 10);

                demographics = UInt32.Parse(demoStr,
                                            System.Globalization.NumberStyles.AllowHexSpecifier |
                                            System.Globalization.NumberStyles.AllowLeadingWhite);

                weightings = UInt32.Parse(weightStr,
                                          System.Globalization.NumberStyles.AllowHexSpecifier |
                                          System.Globalization.NumberStyles.AllowLeadingWhite);

                minMatch = UInt32.Parse(minMatchStr, System.Globalization.NumberStyles.AllowLeadingWhite);
                expiry = UInt32.Parse(expiryStr, System.Globalization.NumberStyles.AllowLeadingWhite);
            }
            catch (Exception) {
                DebugStub.Break();
                return false;
            }

            return true;
        }

        private bool RetrieveUserPersonality(uint userIndex, out uint demographics)
        {
            demographics = 0;
            byte[] fileData = userPersonalityFile.FileData;

            if (fileData == null) {
                return false;
            }

            if (fileData.Length < UserPersonalityFileBytes) {
                return false;
            }

            try {
                int startLine = (int)userIndex * (int)UserPersonalityLineLength;

                // debug!
                string wholeLine = Encoding.ASCII.GetString(fileData, startLine,
                                                            UserPersonalityLineLength);

                if (wholeLine == null) {
                    DebugStub.Break();
                }

                string demoStr = Encoding.ASCII.GetString(fileData, startLine + 6, 8);

                demographics = UInt32.Parse(demoStr,
                                            System.Globalization.NumberStyles.AllowHexSpecifier |
                                            System.Globalization.NumberStyles.AllowLeadingWhite);
            }
            catch (Exception) {
                return false;
            }

            return true;
        }

        private uint GenderWt(uint demVal)
        { return (demVal & 0x000f0000) >> 16; }

        private uint AgeGroupWt(uint demVal)
        { return (demVal & 0x0000f000) >> 12; }

        private uint RegionWt(uint demVal)
        { return (demVal & 0x00000f00) >> 8; }

        private uint InterestWt(uint demVal)
        { return (demVal & 0x000000f0) >> 4; }

        private uint Interest2Wt(uint demVal)
        { return (demVal & 0x0000000f); }

        private void HandleSubstitution(IHttpRequest! request,
                                        string! filePath, string! cookie)
        {
            bool isSmallFile =
                (filePath.IndexOf("class1") != -1) ||
                (filePath.IndexOf("class2") != -1);

            string cookieReject;
            uint userId, lastAd;

            if (!ParseCookie(cookie, out userId, out lastAd, out cookieReject)) {
                WriteErrorResponse(request, 400, (!)cookieReject);
                return;
            }

            if (userId < 10000) {
                WriteErrorResponse(request, 400, "UserID was less than 10,000");
                return;
            }

            uint userIndex = userId - 10000;
            uint userPersonality;
            uint adIndex = lastAd + 1;

            if (adIndex >= CustomAdsLines) {
                adIndex = 0;
            }

            if (!RetrieveUserPersonality(userIndex, out userPersonality)) {
                // BUGBUG: the spec is unclear here; there is no adId to use.
                request.SendHeader(CookiePushHeaderName,
                                   "found_cookie=Ad_Id=-1&Ad_weight=00&Expired=1");
                WriteFileResponse(request, filePath);
            }

            uint adWeight = 0;
            bool expired = false;

            while (adIndex != lastAd) {
                adWeight = 0;
                expired = false;
                uint adDemographics, weightings, minMatch, expiry;

                bool gotAd = RetrieveAdData(adIndex, out adDemographics,
                                            out weightings, out minMatch, out expiry);
                assert gotAd; // we checked the cached adfile above

                uint combinedDemographics = userPersonality & adDemographics;

                if ((combinedDemographics & GENDER_MASK) != 0) {
                    adWeight = adWeight + GenderWt(adDemographics);
                }

                if ((combinedDemographics & AGE_GROUP_MASK) != 0) {
                    adWeight = adWeight + AgeGroupWt(adDemographics);
                }

                if ((combinedDemographics & REGION_MASK) != 0) {
                    adWeight = adWeight + RegionWt(adDemographics);
                }

                if ((combinedDemographics & INTEREST1_MASK) != 0) {
                    adWeight = adWeight + InterestWt(adDemographics);
                }

                if ((combinedDemographics & INTEREST2_MASK) != 0) {
                    adWeight = adWeight + Interest2Wt(adDemographics);
                }

                if (adWeight >= minMatch) {
                    // Found an acceptable match
                    uint now1970Delta = Get1970Time();

                    if (now1970Delta > expiry) {
                        expired = true;
                    }

                    request.SendHeader(CookiePushHeaderName,
                                       "found_cookie=Ad_id=" + adIndex +
                                       "&Ad_weight=" + adWeight +
                                       "&Expired=" + (expired ? "1" : "0"));

                    if (isSmallFile) {
                        WriteSubstitutedFile(request, filePath, adIndex);
                        return;
                    }
                    else {
                        WriteFileResponse(request, filePath);
                        return;
                    }
                }

                adIndex++;
                if (adIndex >= CustomAdsLines) {
                    adIndex = 0; // wrap around
                }
            }

            request.SendHeader(CookiePushHeaderName,
                               "found_cookie=Ad_id=" + adIndex +
                               "&Ad_weight=" + adWeight +
                               "&Expired=" + (expired ? "1" : "0"));

            if (isSmallFile) {
                WriteSubstitutedFile(request, filePath, adIndex);
            }
            else {
                WriteFileResponse(request, filePath);
            }
        }

        ///////////////////////////////////////////////////////////////////////
        //
        // The code below gets used when this webapp is compiled
        // to a stand-alone executable
        //
        internal static int AppMain(Parameters! config)
        {
            WebAppContract.Exp conn = config.webAppRef.Acquire();
            conn.SendWebAppReady();

            SPECWeb99WebApp webApp = new SPECWeb99WebApp(config);
            Driver.ServiceChannel(webApp, conn);
            delete conn;
            return 0;
        }

        //////////////////////////////////////////////////////////////////////
        //
        // Code used to retrieve thread times.
        //
        public class ProcessData
        {
            public int id;
            public string name;
            public long memBytes;
            public long peakMemBytes;
            public long commMemBlocks;
            public long commMemBytes;
            public long handlePages;
            public int[] tids;
            public long totalTime;
            public long deadThreadTime;
            public long deadThreadCount;
            public int gcCount;
            public long gcTotalTime;
            public long gcTotalBytes;

            public ProcessData() {
                tids = null;
            }
        }

        public static int []! GetProcessIDs(ProcessContract.Imp:ReadyState! imp)
        {
            int [] ids = null;
            int[]! in ExHeap xids;
            imp.SendGetProcessIDs();
            imp.RecvProcessIDs(out xids);
            // REVIEW: The kernel process is being returned twice so we're
            // skipping one of the entries if the process ID matches.
            int startIndex = 0;
            if (xids[0] == xids[1])
                startIndex++;
            ids = new int[xids.Length - startIndex];
            for (int i = startIndex; i < xids.Length; i++) {
                ids[i - startIndex] = xids[i];
            }
            delete xids;
            return ids;
        }

        public static int [] GetProcessThreadIDs(ProcessContract.Imp:ReadyState! imp, int procID)
        {
            imp.SendGetProcessThreadIDs(procID);
            int [] retVal = null;

            switch receive {
                case imp.NotFound() :
                    break;

                case imp.ProcessThreadIDs(int[]! in ExHeap tids) :
                    retVal = new int[tids.Length];
                    for (int i = 0; i < tids.Length; i++) {
                        retVal[i] = tids[i];
                    }
                    delete tids;
                    break;

                case imp.ChannelClosed() :
                    throw new Exception("GetProcessThreadIDs: imp channel closed");
            }
            return retVal;
        }


        public static void
        GetProcessInfo(ProcessContract.Imp:ReadyState! imp,
                       ProcessData[]! processData
                       )
        {
            for (int i = 0; i < processData.Length; i++) {
                ProcessData! pd = (!)processData[i];
                imp.SendGetProcessTimes(pd.id);
                imp.RecvProcessTimes(out pd.totalTime, out pd.deadThreadTime, out pd.deadThreadCount);
                pd.totalTime += pd.deadThreadTime;
                imp.SendGetProcessGcStats(pd.id);
                imp.RecvProcessGcStats(out pd.gcCount, out pd.gcTotalTime, out pd.gcTotalBytes);
            }
        }

        public static string []! GetProcessNames(ProcessContract.Imp:ReadyState! imp, int []! ids)
        {
            string [] names = new string[ids.Length];
            for (int i = 0; i < ids.Length; i++) {
                imp.SendGetProcessName(ids[i]);

                switch receive {
                    case imp.NotFound() :
                        break;

                    case imp.ProcessName(char[]! in ExHeap procName) :
                        names[i] = Bitter.ToString(procName);
                        delete procName;
                        break;

                    case imp.ChannelClosed() :
                        throw new Exception("GetProcessNames: imp channel closed");
                }
            }
            return names;
        }

        public static void GetMemoryUsage(MemoryContract.Imp:ReadyState! imp, ProcessData[]! processData)
        {
            for (int i = 0; i < processData.Length; i++) {
                ProcessData! pd = (!)processData[i];
                imp.SendGetProcessUsedMemory(pd.id);
                imp.RecvMemory(out pd.memBytes);

                imp.SendGetProcessPeakMemory(pd.id);
                imp.RecvMemory(out pd.peakMemBytes);

                imp.SendProcessUsedCommunicationHeap(pd.id);
                imp.RecvBlocksAndTotal(out pd.commMemBlocks, out pd.commMemBytes);

                imp.SendGetProcessHandlePages(pd.id);
                imp.RecvPages(out pd.handlePages);
            }
        }

        public static ProcessData[]! GetProcessData(ProcessContract.Imp:ReadyState! imp)
        {
            int [] ids = GetProcessIDs(imp);
            string [] names = GetProcessNames(imp, ids);

            ProcessData [] processData = new ProcessData[ids.Length];
            for (int i = 0; i < ids.Length; i++) {
                ProcessData! pd = new ProcessData();
                pd.id          = ids[i];
                pd.name        = names[i];
                pd.tids        = GetProcessThreadIDs(imp, ids[i]);
                processData[i] = pd;
            }
            GetProcessInfo(imp, processData);

            return processData;
        }
    }

    // AMD Performance Counter Code

    [CLSCompliant(false)]
    public struct PerfEvtSel
    {
        // Bits and Flags
        public const uint CNT_MASK  = 0xff000000;
        public const uint INV       = 0x00800000;
        public const uint EN        = 0x00400000;
        public const uint INT       = 0x00100000;
        public const uint PC        = 0x00080000;
        public const uint E         = 0x00040000;
        public const uint OS        = 0x00020000;
        public const uint USR       = 0x00010000;
        public const uint UNIT_MASK = 0x0000ff00;
        public const uint SELECTOR  = 0x000000ff;

        // Common setting: Count all, but don't interrupt,
        public const uint COUNT     = (EN | PC | OS | USR);
        // public const uint COUNT     = (EN | PC | E | OS | USR);

        // Selector values.
        public const uint DCacheRefillFromL2OrSys           = 0x42; // Speculative
        public const uint DCacheRefillFromSystem            = 0x43; // Speculative
        public const uint DtlbL1MissL2Hit                   = 0x45; // Speculative
        public const uint DtlbL1MissL2Miss                  = 0x46; // Speculative
        public const uint CyclesNotHalted                   = 0x76; // No E
        public const uint RequestsToL2Cache                 = 0x7d;
        public const uint L2CacheMiss                       = 0x7e;
        public const uint ItlbL1MissL2Hit                   = 0x84;
        public const uint ItlbL1MissL2Miss                  = 0x85;
        public const uint RetiredInstructions               = 0xc0; // No E
        public const uint RetiredBranchInstructions         = 0xc2; // No E
        public const uint RetiredBranchesMispredicted       = 0xc3; // No E
        public const uint RetiredBranchesTaken              = 0xc4; // No E
        public const uint CyclesInterruptsMasked            = 0xcd; // No E
        public const uint CyclesInterruptsBlocked           = 0xce; // No E

        public ulong value; // Required so Bartok doesn't die.

        public static string ToString(ulong value)
        {
            switch (value & 0xff) {
                case PerfEvtSel.DCacheRefillFromL2OrSys:    return "DCache_Refill_L2";
                case PerfEvtSel.DCacheRefillFromSystem:     return "DCache_Refill_Sys";
                case PerfEvtSel.DtlbL1MissL2Hit:            return "DTLB_L2_Hit";
                case PerfEvtSel.DtlbL1MissL2Miss:           return "DTBL_L2_Miss";
                case PerfEvtSel.CyclesNotHalted:            return "CyclesNotHalted";
                case PerfEvtSel.RequestsToL2Cache:
                    if ((value & 0x400) != 0) {
                        return "TLB_L2_Requests";
                    }
                    return "Req_L2_Cache";
                case PerfEvtSel.L2CacheMiss:
                    if ((value & 0x400) != 0) {
                        return "TLB_L2_Miss";
                    }
                    return "L2_Cache_Miss";
                case PerfEvtSel.ItlbL1MissL2Hit:            return "ITLB_L2_Hit";
                case PerfEvtSel.ItlbL1MissL2Miss:           return "ITLB_L2_Miss";
                case PerfEvtSel.RetiredInstructions:        return "Retired_Inst.";
                case PerfEvtSel.RetiredBranchInstructions:  return "Branches";
                case PerfEvtSel.RetiredBranchesMispredicted:return "Br_Mispredicted";
                case PerfEvtSel.RetiredBranchesTaken:       return "Br_Taken";
                case PerfEvtSel.CyclesInterruptsMasked:     return "Ints_Masked (cyc)";
                case PerfEvtSel.CyclesInterruptsBlocked:    return "Ints_Blocked (cyc)";
                default:
                    return String.Format("{0:x16}", value);
            }
        }
    }
}