Quick Open File for Visual Studio

Have you ever worked on a big solution? sometimes with many projects?

Going back and forth in the solution explorer could waste a lot of your time, if you're a bit tired just before getting a version out its even worse, not to mention getting you out of focus.

I'm a big fan of Quick Open File, I think you will too when you try it.

Just remember Ctrl-K O and type the file you're looking for.

http://visualstudiogallery.msdn.microsoft.com/3eb2f230-2728-4d5f-b448-4c0b64154da7


Update 2012-08-22: You can always use the Navigate To, or Ctrl+, key combination:

I've discovered this while looking for a similar solution in VS2012, its showing too much information, but its better than digging through the solution files and you can always type the extension.

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Dror Gluska June 01, 2012  No comment

Tuples

So what are tuples?


Tuples are a generic data structures, it can contain 1 - 8 data items.


What are they used for? anything you want them to, they are serializable, so you can use them in your WCF projects, they are simple, so you can use them when you want to pass a number of parameters back from a method without creating a special structure just for that method.


Lets say I have a method which returns an ordered and paged list of items, but I also want to know how many items are in the list without going to a different method.


You can do something like this:

public static Tuple<int, List<string>> GetPagedItems(int from, int len)
        {
            var list = GenerateStringList(1000);

            var listcount  = list.Count();
            var subset = list.OrderBy(i => i).Skip(from).Take(len).ToList();

            return new Tuple<int, List<string>>(listcount, subset);
        }

The uses are only limited by your imagination, since .NET supports covariance and contravariance since 4.0, the sky is the limit.

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Dror Gluska June 01, 2012  No comment

MVC Error page linked with Elmah error code

Recently in a lot of projects I've seen the popularity of using elmah error logger, even more so than log4net, its comfortable, easy to configure and very simple to follow errors. 


If you're developing a business application and want to provide serious support to your customers you'll prefer to give your users some way of describing the error, so avoiding generic error pages is a good practice but you don't want to give them a window into your application, it might open a serious security risk, using elmah's error id is the best option in my opinion, since it gives you the ability to see what went wrong, combine that with either asking the user what they tried to do or incorporating into the exception the data passed into the failing method/action and you have a better way of solving problems.


After digging around, I've seen this, which gave me a lead, so thanks for the info! 


Here's the simplest way of doing it (there's a demo project at the end of this post):


1. Add Elmah.Contrib.Mvc, you can do it via the NuGet packages.


2. Change your web.config to persist the errors, disk/sql or what ever you like, this way the id will mean something if the application is restarted, because the default is memory.


3. Set custom errors in web.config, for example: 
<customErrors mode="On" defaultRedirect="~/Demo/ShowError" />


4. If you want all the errors to be caught by elmah, you'll have to comment this line in global.asax -> void RegisterGlobalFilters(GlobalFilterCollection filters):
 filters.Add(new HandleErrorAttribute());


The default error handler doesn't alert elmah when an exception is thrown and custom errors are on.


5. Add this to your global.asax, its for elmah to handle your errors:

protected void ErrorLog_Logged(object sender, ErrorLoggedEventArgs args)
        {
            var result = ElmahErrorHandling.ProcessError(sender, args);
            if (!string.IsNullOrEmpty(result))
                Response.Redirect(result);
        }

6. Insert this class in your project:

/// <summary>
    /// Elmah Error handling helper class
    /// </summary>
    public class ElmahErrorHandling
    {
        /// <summary>
        /// Configuration
        /// </summary>
        public static Configuration config = WebConfigurationManager.OpenWebConfiguration("~");

        /// <summary>
        /// CustomErrors configuration section
        /// </summary>
        public static CustomErrorsSection customErrorsSection = (CustomErrorsSection)config.GetSection("system.web/customErrors");

        /// <summary>
        /// Handlers configuration section
        /// </summary>
        public static HttpHandlersSection handlers = (HttpHandlersSection)config.GetSection("system.web/httpHandlers");

        /// <summary>
        /// Process errors caught in Global.asax
        /// <para>should be inside protected void ErrorLog_Logged(object sender, ErrorLoggedEventArgs args)</para>
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="args"></param>
        /// <returns>null if no custom error should be displayed or a link if redirect is required to the specific location</returns>
        public static string ProcessError(object sender, ErrorLoggedEventArgs args)
        {
            if (customErrorsSection != null)
            {
                switch (customErrorsSection.Mode)
                {
                    case CustomErrorsMode.Off:
                        break;
                    case CustomErrorsMode.On:
                        return customErrorsSection.DefaultRedirect + "?id=" + args.Entry.Id;
                    case CustomErrorsMode.RemoteOnly:
                        if (!HttpContext.Current.Request.IsLocal)
                            return customErrorsSection.DefaultRedirect + "?id=" + args.Entry.Id;
                        break;
                }
            }

            return null;
        }

        /// <summary>
        /// Get path to Elmah error handler
        /// <para>e.g. elmah.axd</para>
        /// </summary>
        /// <returns></returns>
        public static string GetElmahHandler()
        {
            if ((handlers != null) && (handlers.Handlers != null))
                for (int i = 0; i < handlers.Handlers.Count; i++)
                    if (handlers.Handlers[i].Type.IndexOf("elmah", StringComparison.InvariantCultureIgnoreCase) != -1)
                        return handlers.Handlers[i].Path;
                
            return null;
        }

        /// <summary>
        /// Gets absolute path to elmah error log
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        public static string GetHandlerLink(string id)
        {
            return VirtualPathUtility.ToAbsolute(string.Format("~/{0}/detail?id={1}",GetElmahHandler(), id));
        }

        /// <summary>
        /// Gets Error string according to configuration and id
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        public static string GetErrorString(string id)
        {
            if (customErrorsSection != null)
            {
                switch (customErrorsSection.Mode)
                {
                    case CustomErrorsMode.Off:
                        return string.Format("<a href='{0}'>{1}</a>",GetHandlerLink(id),id);
                    case CustomErrorsMode.On:
                    case CustomErrorsMode.RemoteOnly:
                        if (HttpContext.Current.Request.IsLocal)
                            return string.Format("<a href='{0}'>{1}</a>", GetHandlerLink(id),id);
                        else
                            return id;
                }
            }
            return string.Empty;
        }

        /// <summary>
        /// returns MvcHtmlString for error link/text
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        public static MvcHtmlString GetError(string id)
        {
            return new MvcHtmlString(GetErrorString(id));
        }
    }

7. Create your error page, make sure its the correct path in customErrors section in your web.config and add this:
@ElmahErrorHandling.GetError(ViewBag.id)


It will either display a link to elmah.axd or an id, depending on your configuration.




There's a demo project at:
https://github.com/drorgl/ForBlog/tree/master/MvcElmahErrorDemo

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Dror Gluska June 01, 2012  No comment

Hierarchy Cache

In the past I tried to avoid using hierarchies in SQL, but I couldn't find another simple data structure for a system requirement: all elements must be children of other elements with no depth limit.


I was able to change the depth limit to 100.


So I started out with:

CREATE TABLE [dbo].[Hierarchy](
    [ElementId] [int] IDENTITY(1,1) NOT NULL,
    [ParentId] [int] NULL,
 CONSTRAINT [PK_Hierarchy] PRIMARY KEY CLUSTERED 
(
    [ElementId] ASC
)

at first everything worked fine, I could traverse the tree with CTE without any problem, it was even fast for the current load, then came another system requirement, the tree size will be about 1 million records.

with cte as
(
 select ElementId, ParentId, 0 as Level
 from Hierarchy
 where ParentId is null
 
 union all
 
 select Hierarchy.ElementId, Hierarchy.ParentId, Level + 1
 from Hierarchy
  join cte on cte.ElementId = Hierarchy.ParentId
)

select * from cte

trying to traverse a tree of 1M records with CTE with only 15 levels took more than a production sql should take, even if the system's requirement should be live or near live.


We've been looking for solutions in every corner of the internet, graph databases (we'll still need to use these IDs in the SQL so passing the data back will be a design nightmare or we can move the portions or whole application, I guess these are other options), trying to find all sorts of algorithms (which will be error prune and might be a heavy toll on the development team), CLR functions and of curse scrapping the whole hierarchy idea (no can do, system requirements).


Eventually we came to the conclusion that keeping a cache will not be too costly on the memory, cpu and disk provided that the right indexes will be created and they will provide the best result and the fun part is, its very easy and fast to join the cache table on any other table we'll need. 


But we had to compromise somewhere, we compromised on node parent changes, some of them might cause the entire tree to rebuild.


I built a method to quickly update the tree given an elementid and if elementid was not provided, it will rebuild the whole tree.


I can smell just one little problem, which will be solved when updating records, need to detect circular references.

CREATE TABLE [dbo].[HierarchyCache](
 [OwnerId] [int] NOT NULL,
 [ElementId] [int] NOT NULL
)

And the SQL code updating the HierarchyCache, note that I'm using merge instead of dropping the whole table or writing individual insert/delete.

declare @ElementId int = null


--if no ElementId was supplied, it means we should go over all Hierarchy and rebuild the table
if (@ElementId is null)
begin


    with parentHierarchy (ElementId, ParentId , TopElementId)
    as
    (
        select  ElementId, ParentId, ElementId as TopElementId
        from Hierarchy with (nolock)

        union all

        select  [Hierarchy].ElementId,[Hierarchy].ParentId , pu.TopElementId
        from Hierarchy with (nolock)
        inner join parentHierarchy as pu
            on pu.ParentId = [Hierarchy].ElementId
    )

    --instead of updating the entire table, we're doing a merge, more efficient and easier on the disk
    merge into HierarchyCache as target
    using parentHierarchy
        on (parentHierarchy.TopElementId = target.OwnerId and parentHierarchy.ElementId = target.ElementId)
    when not matched by target then
        insert (ElementId, OwnerId) values (parentHierarchy.ElementId,parentHierarchy.TopElementId)
    when not matched by source then
        delete;

end
else
begin
    --a ElementId was supplied, update only its tree

    with parentHierarchy (ElementId, ParentId  , TopElementId)
    as
    (
        select  ElementId, ParentId , ElementId as TopElementId
        from Hierarchy with (nolock)
        where ElementId = @ElementId

        union all

        select  [Hierarchy].ElementId,(case when (Hierarchy.ParentId = Hierarchy.ElementId) then null else Hierarchy.ParentId end) as ParentId , pu.TopElementId
        from Hierarchy  with (nolock)
        inner join parentHierarchy as pu
            on pu.ParentId = [Hierarchy].ElementId

    )

    --instead of updating the entire table, we're doing a merge, more efficient and easier on the disk
    merge into HierarchyCache as target
    using parentHierarchy
        on (parentHierarchy.TopElementId = target.OwnerId and parentHierarchy.ElementId = target.ElementId)
    when not matched by target then
        insert (ElementId, OwnerId) values (parentHierarchy.ElementId,parentHierarchy.TopElementId);


end

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Tags: cte, hierarchy, merge, sql

Dror Gluska May 25, 2012  No comment

Mikrotik

Many years ago when I was doing some IT work for the company I worked for, I needed routers, I had many PCs laying around so getting a few NICs and installing them was not a problem, I've tried many open source routers but they couldn't handle the IGMP packets properly and after a few seconds the PPTP VPN connections would drop.


Until I met MikroTik, its not a freeware, but it costs very little for what it can do ($45), I've been using it since to help low budget IT departments have professional grade routing.

Level number	0 (Demo mode)	1 (Free)	3 (WISP CPE)	4 (WISP)	5 (WISP)	6 (Controller)
Price	no key	registration required	volume only	$45	$95	$250
Upgradable To	-	no upgrades	ROS v6.x	ROS v6.x	ROS v7.x	ROS v7.x
Initial Config Support	-	-	-	15 days	30 days	30 days
Wireless AP	24h trial	-	-	yes	yes	yes
Wireless Client and Bridge	24h trial	-	yes	yes	yes	yes
RIP, OSPF, BGP protocols	24h trial	-	yes(*)	yes	yes	yes
EoIP tunnels	24h trial	1	unlimited	unlimited	unlimited	unlimited
PPPoE tunnels	24h trial	1	200	200	500	unlimited
PPTP tunnels	24h trial	1	200	200	500	unlimited
L2TP tunnels	24h trial	1	200	200	500	unlimited
OVPN tunnels	24h trial	1	200	200	unlimited	unlimited
VLAN interfaces	24h trial	1	unlimited	unlimited	unlimited	unlimited
HotSpot active users	24h trial	1	1	200	500	unlimited
RADIUS client	24h trial	-	yes	yes	yes	yes
Queues	24h trial	1	unlimited	unlimited	unlimited	unlimited
Web proxy	24h trial	-	yes	yes	yes	yes
User manager active sessions	24h trial	1	10	20	50	Unlimited
Number of KVM guests	none	1	Unlimited	Unlimited	Unlimited	Unlimited

They also have appliances, take a look at their website.


I do not get percentages, but I did went through one of their courses in Florida at 2005.

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Tags: mikrotik, router

Dror Gluska May 25, 2012  No comment

Dictionary vs ConcurrentDictionary

Who hasn't seen in almost every best practices guide "cache everything!", but what they forget to tell you is that by that time, the caching you're using is one of the biggest bottlenecks of your program, you try to use as many dictionaries as you can (at least for a particular caching need) and avoid locking and blocking in any way possible.


When Microsoft decided its time for .NET to start using multi-threading heavily, they came out with Parallel Extensions, later on they added ConcurrentDictionary, but I've always wondered what is the price we're paying for the dictionary to work in a thread-safe environment.


I can't stress this enough, Do not use a regular Dictionary with multi-threading!
In some cases when the dictionary is updated by two (or more) threads it will corrupt its internal structures and it will throw exceptions. sometimes items will disappear, sometimes the whole dictionary will stop working.


In the past I've implemented a dictionary with lock keyword, spinlock, read/write locks and even a copying dictionary so whenever you had to make a change, it will copy itself, make the modification and replace the reference, I didn't care about losing information, I just wanted the quickest dictionary.


So how does the ConcurrentDictionary works? well, using ILSpy, we can take a look, I can't post the source code here so you'll have to do your own digging, but apparently its using Monitor.Enter for the writing portion, which is just an alternative of the lock keyword, for the reading portion it seems that its pretty close to the regular Dictionary.


I remembered reading about lock-free hashmaps (PDF) in the past but didn't have the time looking up the algorithm, understanding it and implementing it, luckily someone already did but I can't find the original C# implementation, here's what I've found now https://github.com/hackcraft/Ariadne.




I did some benchmarks and the results are pretty interesting.
The categories (X) are the number of concurrent threads attempting to write and read.
Note: the graphs do not work in IE for now.


You may find the benchmark project at:
https://github.com/drorgl/ForBlog/tree/master/DictionaryBenchmarks


I've taken the readwrite locked dictionary from Lorenz Cuno Klopfenstein, I've implemented a minimal spinlock dictionary just for the test, don't use it.


The ThreadSafeDictionary is the star of this benchmarks, it performs exceptionally well, so if your program relies heavily on dictionaries and threading, use it.

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Tags: benchmarks, C#, ConcurrentDictionary, Dictionary, locks, threads

Dror Gluska May 24, 2012  1 comment

Showing dynamic graphs in a blog

Lets face it, those static graphs in blogs are sometimes completely useless, sometimes one bar is overpowering the rest, you can't really edit the data easily, and don't even mention changing the graph type on the fly, including a few graph types in the same page? huh! you must be joking, why would I overcrowd the page just for ease of use?


Here's what I came up with, its doesn't have that flashy select box with multiple graph types, but it should be pretty easy to add.


Update: The demo page is not working in IE, the host I'm using is serving javascript files as text/plain instead of text/javascript.


First, create graph data in google spreadsheet, make sure you publish the spreadsheet, otherwise you won't have the url needed (File -> publish to the web -> Start Publishing)


Then create a page in the blog with this code (or similar), make sure you have the correct urls, for the scripts and your spreadsheet.

 <script src="Scripts/jquery-1.4.1.min.js" type="text/javascript"></script>
 <script src="Scripts/google-spreadsheet.js" type="text/javascript"></script>
 <script src="Scripts/google-spreadsheet-parser.js" type="text/javascript"></script>
 <script src="http://code.highcharts.com/highcharts.js"></script>

     <div id="readContainer"></div>
     <div id="writeContainer"></div>

    <script type="text/javascript">


        //container: div container
        //type: 'line' for example
        //title: 'Dictionary Benchmarks'
        //categories: array of x-graph
        //ytitle: y graph title
        function DrawChart(container, type, title, categories, ytitle, series)
        {
            var chart = new Highcharts.Chart({
                chart: {
                    renderTo: container,
                    type: type,
                    marginRight: 130,
                    marginBottom: 25
                },
                title: {
                    text: title,
                    x: -20 //center
                },
                //                subtitle: {
                //                    text: 'Source: WorldClimate.com',
                //                    x: -20
                //                },
                xAxis: {
                    categories: categories
                },
                yAxis: {
                    title: {
                        text: ytitle
                    },
                    plotLines: [{
                        value: 0,
                        width: 1,
                        color: '#808080'
                    }]
                },
                tooltip: {
                    formatter: function ()
                    {
                        return '<b>' + this.series.name + '</b><br/>' +
     this.x + ': ' + this.y + '';
                    }
                },
                legend: {
                    layout: 'vertical',
                    align: 'right',
                    verticalAlign: 'top',
                    x: -10,
                    y: 100,
                    borderWidth: 0
                },
                series: series
            });
            return chart;
        }


        function ChartFromDictionaryData(container,sparser, rows, title, ytitle)
        {

            //need to do read / write / only

            //get all dictionary types
            var serieslist = sparser.DistinctByColumn(rows, "Dictionary");
            delete serieslist["Dictionary"];

            //get all threads
            var threads = sparser.DistinctByColumn(rows, "Threads");
            delete threads["Threads"];

            //highcharts categories 
            var categories = [];
            for (var thread in threads)
            {
                categories.push(parseInt(thread));
            }
            categories.sort(function (a, b) { return a - b; });


            //foreach dictionary, get all rows, order by threads, get timing

            var highchartseries = [];
            for (var series in serieslist)
            {
                var newseries = {};
                newseries.name = series;
                newseries.data = [];
                var rowdata = sparser.FilterByColumn(rows, "Dictionary", series);
                for (var thread in threads)
                {
                    var rowvalue = parseInt(sparser.GetValue(sparser.FilterByColumn(rowdata, "Threads", thread), "Time"));
                    newseries.data.push(rowvalue);
                }
                highchartseries.push(newseries);
            }
            DrawChart(container, "line", title, categories, ytitle, highchartseries);

        }



        localStorage.clear();

//replace with your published spreadsheet url
        var url = "https://docs.google.com/spreadsheet/pub?key=0Akqqf0SS9IbJdFVuZ0hzQnNKcFVFeGJkTzRHdWhYRVE&output=html";
        var googleSpreadsheet = new GoogleSpreadsheet();
        googleSpreadsheet.url(url);
        googleSpreadsheet.load(function (result)
        {
            try
            {
                var sparser = new GoogleSpreadsheetParser(result);

                var readrows = sparser.FilterByColumn(sparser.FilterByColumn(sparser.GetAllRows(), "Read", "TRUE"), "Write", "FALSE");
                var writerows = sparser.FilterByColumn(sparser.FilterByColumn(sparser.GetAllRows(), "Read", "FALSE"), "Write", "TRUE");

                ChartFromDictionaryData('readContainer',sparser, readrows, "Dictionary Benchmarks - Read", "Time (ms) per 1 million operations");
                ChartFromDictionaryData('writeContainer',sparser, writerows, "Dictionary Benchmarks - Write", "Time (ms) per 1 million operations");

                //$('#results').html(JSON.stringify(result).replace(/,/g, ",\n"));
            } catch (e)
            {
                alert(e);
            }
        });
    </script>

and voila, you have a dynamic chart.


Take a loot at highcharts, I have yet to see a better charting library, the graph selection is great:


http://www.highcharts.com/


I took the idea from Mike McKay, here, but I've modified his code and added some of mine, there's a test project at   https://github.com/drorgl/ForBlog/tree/master/GoogleSpreadsheetReader and the files are in https://github.com/drorgl/ForBlog/tree/master/GoogleSpreadsheetReader/Scripts feel free to use it.


Here's an example I did today:
http://uhurumkate.blogspot.com/p/graph-test.html


And one last bit of information, this link might help you to understand what google spreadsheets can do for you - as a datasource.
http://www.goopal.org/google-sites-business/google-spreadsheets/spreadsheet-output/publish-spreadsheet

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Tags: google spreadsheets, graphs, highcharts, javascript

Dror Gluska May 22, 2012  No comment

.NET Composition

.NET 4.0 Provides an easy way for runtime or aftermarket plugins and components, its called Composition.


Before composition we had to load each assembly, check its types and create new instances, I've provided a demo in class PreCompositionInfrastructure.


Composition provides that infrastructure and more, it allows you to specify if you want only one object or multiple, you can specify imports by attribute or by method, specify exports by type or contract, lazy initialization of imports by type or contact.


You just need to add a reference to System.ComponentModel.Composition, create a catalog with directory or assembly and when one is not enough, you can aggregate catalogs.


Then you can either get specific plugins with GetExportedValue or GetExportedValues, or you can let composition do it automatically with ComposeParts, but you'll have to use property attributes to specify which properties will be populated with which plugins and if its many or just one.


On the plugin side, you need to add a reference to System.ComponentModel.Composition and specify which class is an Export of which interface/contract, of curse you have to have access to the same interface from both the imports and the exports, so I recommend using another class library for that interface(s).


And we have to have some benchmarks, but its not really an issue since most applications load plugins at startup and never touch it again and its a lot better having an easy to program infrastructure rather than a quick one if its not affecting the overall performance of the application.


For 1000 iterations:
PluginInfrastructre - 1846ms
PluginInfrastructureImports - 1951ms
(More or less the same time, deviation because of unrelated changes)
PreCompositionInfrastructure - 294ms

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Dror Gluska May 19, 2012  No comment

Microsoft DNS Web Admin

Most if not all DNS servers have a web interface, why not Microsoft's DNS?


I decided to write one, just because I got tired from logging in to a server every time I wanted to change something, yes, I know about remote management, it wasn't an option for that particular case. time passed by and by the time I was almost done, the project was irrelevant, I did have some fun writing it though!


So here it is before you, mostly working, some parts don't, mostly tested. 


https://github.com/drorgl/MSDNSWebAdmin


If you'd like to finish it, enjoy, its on github just for that.






Project contains two interesting libraries:


Heijden.DNS - for querying everything a DNS can tell you, including a trace.


DNSManagement - C# wrapper for WMI MicrosoftDNS namespace.

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Tags: C#, dns, microsoft, web admin, web interface, wmi

Dror Gluska April 27, 2012  1 comment

Unix to DateTime to Unix

If you need to convert from .NET DateTime to Unix datetime and back, here's how:

/// <summary>
/// Converts a unix datetime to C# DateTime
/// </summary>
/// <param name="unixTimeStamp"></param>
/// <returns></returns>
public static DateTime UnixTimeStampToDateTime(double unixTimeStamp)
{
    // Unix timestamp is seconds past epoch
    System.DateTime dtDateTime = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
    dtDateTime = dtDateTime.AddSeconds(unixTimeStamp).ToUniversalTime();
    return dtDateTime;
}


/// <summary>
/// Converts C# DateTime to unix datetime
/// </summary>
/// <param name="dateTime"></param>
/// <returns></returns>
public static double DateTimeToUnixTimestamp(DateTime dateTime)
{
    return (dateTime.ToUniversalTime() - new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc).ToUniversalTime()).TotalSeconds;
}

From here.

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Dror Gluska April 10, 2012  No comment