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  • C++/CLI HTTP Proxy problems...

    - by darkantimatter
    Hi, I'm trying(very hard) to make a small HTTP Proxy server which I can use to save all communications to a file. Seeing as I dont really have any experience in the area, I used a class from codeproject.com and some associated code to get started (It was made in the old CLI syntax, so I converted it). I couldn't get it working, so I added lots more code to make it work (threads etc), and now it sort of works. Basically, it recieves something from a client (I just configured Mozilla Firefox to route its connections through this proxy) and then routes it to google.com. After it sends Mozilla's data to google, recieves a responce, and sends that to Mozilla. This works fine, but then the proxy fails to recieve any data from Mozilla. It just loops in the Sleep(50) section. Anyway, heres the code: ProxyTest.cpp: #include "stdafx.h" #include "windows.h" #include "CHTTPProxy.h" public ref class ClientThread { public: System::Net::Sockets::TcpClient ^ pClient; CHttpProxy ^ pProxy; System::Int32 ^ pRecieveBufferSize; System::Threading::Thread ^ Thread; ClientThread(System::Net::Sockets::TcpClient ^ sClient, CHttpProxy ^ sProxy, System::Int32 ^ sRecieveBufferSize) { pClient = sClient; pProxy = sProxy; pRecieveBufferSize = sRecieveBufferSize; }; void StartReading() { Thread = gcnew System::Threading::Thread(gcnew System::Threading::ThreadStart(this,&ClientThread::ThreadEntryPoint)); Thread->Start(); }; void ThreadEntryPoint() { char * bytess; bytess = new char[(int)pRecieveBufferSize]; memset(bytess, 0, (int)pRecieveBufferSize); array<unsigned char> ^ bytes = gcnew array<unsigned char>((int)pRecieveBufferSize); array<unsigned char> ^ sendbytes; do { if (pClient->GetStream()->DataAvailable) { try { do { Sleep(100); //Lets wait for whole packet to get cached (If it even does...) unsigned int k = pClient->GetStream()->Read(bytes, 0, (int)pRecieveBufferSize); //Read it for(unsigned int i=0; i<(int)pRecieveBufferSize; i++) bytess[i] = bytes[i]; Console::WriteLine("Packet Received:\n"+gcnew System::String(bytess)); pProxy->SendToServer(bytes,pClient->GetStream()); //Now send it to google! pClient->GetStream()->Flush(); } while(pClient->GetStream()->DataAvailable); } catch (Exception ^ e) { break; } } else { Sleep(50); //It just loops here because it thinks mozilla isnt sending anything if (!(pClient->Connected)) break; }; } while (pClient->GetStream()->CanRead); delete [] bytess; pClient->Close(); }; }; int main(array<System::String ^> ^args) { System::Collections::Generic::Stack<ClientThread ^> ^ Clients = gcnew System::Collections::Generic::Stack<ClientThread ^>(); System::Net::Sockets::TcpListener ^ pTcpListener = gcnew System::Net::Sockets::TcpListener(8080); pTcpListener->Start(); System::Net::Sockets::TcpClient ^ pTcpClient; while (1) { pTcpClient = pTcpListener->AcceptTcpClient(); //Wait for client ClientThread ^ Client = gcnew ClientThread(pTcpClient, gcnew CHttpProxy("www.google.com.au", 80), pTcpClient->ReceiveBufferSize); //Make a new object for this client Client->StartReading(); //Start the thread Clients->Push(Client); //Add it to the list }; pTcpListener->Stop(); return 0; } CHTTPProxy.h, from http://www.codeproject.com/KB/IP/howtoproxy.aspx with a lot of modifications: //THIS FILE IS FROM http://www.codeproject.com/KB/IP/howtoproxy.aspx. I DID NOT MAKE THIS! BUT I HAVE MADE SEVERAL MODIFICATIONS! #using <mscorlib.dll> #using <SYSTEM.DLL> using namespace System; using System::Net::Sockets::TcpClient; using System::String; using System::Exception; using System::Net::Sockets::NetworkStream; #include <stdio.h> ref class CHttpProxy { public: CHttpProxy(System::String ^ szHost, int port); System::String ^ m_host; int m_port; void SendToServer(array<unsigned char> ^ Packet, System::Net::Sockets::NetworkStream ^ sendstr); }; CHttpProxy::CHttpProxy(System::String ^ szHost, int port) { m_host = gcnew System::String(szHost); m_port = port; } void CHttpProxy::SendToServer(array<unsigned char> ^ Packet, System::Net::Sockets::NetworkStream ^ sendstr) { TcpClient ^ tcpclnt = gcnew TcpClient(); try { tcpclnt->Connect(m_host,m_port); } catch (Exception ^ e ) { Console::WriteLine(e->ToString()); return; } // Send it if ( tcpclnt ) { NetworkStream ^ networkStream; networkStream = tcpclnt->GetStream(); int size = Packet->Length; networkStream->Write(Packet, 0, size); array<unsigned char> ^ bytes = gcnew array<unsigned char>(tcpclnt->ReceiveBufferSize); char * bytess = new char[tcpclnt->ReceiveBufferSize]; Sleep(500); //Wait for responce do { unsigned int k = networkStream->Read(bytes, 0, (int)tcpclnt->ReceiveBufferSize); //Read from google for(unsigned int i=0; i<k; i++) { bytess[i] = bytes[i]; if (bytess[i] == 0) bytess[i] = ' '; //Dont terminate the string if (bytess[i] < 8) bytess[i] = ' '; //Somethings making the computer beep, and its not 7?!?! }; Console::WriteLine("\n\nAbove packet sent to google. Google Packet Received:\n"+gcnew System::String(bytess)); sendstr->Write(bytes,0,k); //Send it to mozilla Console::WriteLine("\n\nAbove packet sent to client..."); //Sleep(1000); } while(networkStream->DataAvailable); delete [] bytess; } return; } Any help would be much appreciated, I've tried for hours.

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  • PHP application failed to connect after a network plugged back in

    - by tntu
    My data-center appears to have had some issues with their network and thus my server has suffered from on an off network connectivity for about an hour. After the connection has been completely re-established my code still kept reporting the same issue over and over until I have restarted the service. The code is a simple PHP code that loops forever checking the Apple feed-back server and then sleeps for a few minutes and then it begins all over again. Now I understand the error being generated if the network is down but once it got back up why did it continue until I have restarted the code? Does PHP have something that needs to be re-initialized or something?? Messges log: Dec 20 08:57:22 server kernel: r8169: eth0: link down Dec 20 08:57:28 server kernel: r8169 0000:06:00.0: eth0: link up Dec 20 08:57:29 server kernel: r8169: eth0: link down Dec 20 08:57:33 server kernel: r8169 0000:06:00.0: eth0: link up Dec 20 08:57:33 server kernel: r8169: eth0: link down Dec 20 08:57:37 server kernel: r8169 0000:06:00.0: eth0: link up Dec 20 08:57:38 server kernel: r8169: eth0: link down Dec 20 08:57:44 server kernel: r8169 0000:06:00.0: eth0: link up Dec 20 08:57:44 server kernel: r8169: eth0: link down Dec 20 08:57:52 server kernel: r8169 0000:06:00.0: eth0: link up Dec 20 08:57:52 server kernel: r8169: eth0: link down Dec 20 09:10:58 server kernel: r8169 0000:06:00.0: eth0: link up PHP Error: PHP Warning: stream_socket_client(): php_network_getaddresses: getaddrinfo failed: Name or service not known in /home/push/feedback.php on line 36 Code Line 36: $apns = stream_socket_client('ssl://feedback.sandbox.push.apple.com:2196', $errcode, $errstr, 60, STREAM_CLIENT_CONNECT, $stream_context);

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  • System With Two Network Adapters

    - by Synetech inc.
    Hi, My system has a NIC (Marvell Yukon) built-into the motherboard, but I also have a D-Link (RealTek) card. I figure that using the D-Link and disabling the Marvell makes the most sense, though I'm wondering if maybe the built-in one has better throughput (not that my Internet connection is so fast). Also, I'm wondering about the merits of using both at the same time. My router has four ports and I have experimented with enabling and plugging both NICs into the router. I was able to connect to the Internet, but the pattern of usage seemed irregular (which adapter was chosen for the transfer and any given point). I also considered bridging the two, but am having difficulty in finding out what exactly creating network bridge does in the context of the Windows Network Connections window. I am familiar with the concept of connecting networks, so it seems to me that birding two connections on the same segment is pointless at best (and can cause problems like loops?) Does anyone have any tips on what to do if a system has more than one NIC and any clarification on the bridge option? Thanks a lot.

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  • Can you see something wrong in my .htaccess?

    - by AlexV
    OK, after many search, trial and errors I've managed to create an .htaccess that do what I wanted (see explanations and questions after the code block): <IfModule mod_rewrite.c> RewriteEngine On #1 If the requested file is not url-mapper.php (to avoid .htaccess loop) RewriteCond %{REQUEST_FILENAME} (?<!url-mapper\.php)$ #2 If the requested URI does not end with an extension OR if the URI ends with .php* RewriteCond %{REQUEST_URI} !\.(.*) [OR] RewriteCond %{REQUEST_URI} \.php.*$ [NC] #3 If the requested URI is not in an excluded location RewriteCond %{REQUEST_URI} !^/seo-urls\/(excluded1|excluded2)(/.*)?$ #Then serve the URI via the mapper RewriteRule .* /seo-urls/url-mapper.php?uri=%{REQUEST_URI} [L,QSA] </IfModule> This is what the .htaccess should do: #1 is checking that the file requested is not url-mapper.php (to avoid infinite redirect loops). This file will always be at the root of the domain. #2 the .htaccess must only catch URLs that don't end with an extension (www.foo.com -- catch | www.foo.com/catch-me -- catch | www.foo.com/dont-catch.me -- don't catch) and URLs ending with .php* files (.php, .php4, .php5, .php123...). #3 some directories (and childs) can be excluded from the .htaccess (in this case /seo-urls/excluded1 and /seo-urls/excluded2). Finally the .htaccess feed the mapper with an hidden GET parameter named uri containing the requested uri. Even if I tested and everything works, I want to know if what I do is correct (and if it's the "best" way to do it). I've learned a lot with this "project" but I still consider myself a beginner at .htaccess and regular expressions so I want to triple check it there before putting it in production...

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  • System With Two Network Adapters [closed]

    - by Synetech inc.
    Hi, My system has a NIC (Marvell Yukon) built-into the motherboard, but I also have a D-Link (RealTek) card. I figure that using the D-Link and disabling the Marvell makes the most sense, though I'm wondering if maybe the built-in one has better throughput (not that my Internet connection is so fast). Also, I'm wondering about the merits of using both at the same time. My router has four ports and I have experimented with enabling and plugging both NICs into the router. I was able to connect to the Internet, but the pattern of usage seemed irregular (which adapter was chosen for the transfer and any given point). I also considered bridging the two, but am having difficulty in finding out what exactly creating network bridge does in the context of the Windows Network Connections window. I am familiar with the concept of connecting networks, so it seems to me that birding two connections on the same segment is pointless at best (and can cause problems like loops?) Does anyone have any tips on what to do if a system has more than one NIC and any clarification on the bridge option? Thanks a lot.

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  • optimize mod_rewrite in htaccess

    - by clarkk
    I got some mod_rewrite conditions in a .htaccess file which I have extended from time to time.. But I don't think its very well written (I'm still quite new to mod_rewrite) Some times requests end up in infinite loops And just now I added SSL to the file.. When requesting https:// I get a 404 error The requested URL /_secure/_secure/ was not found on this server. Somehow it adds an extra _secure to the path? .htacces # set language RewriteCond %{HTTP_HOST} ^www\. [NC] RewriteCond %{REQUEST_URI} ^/(da|en)/(.*)(\?%{QUERY_STRING})?$ [NC] RewriteRule ^(.*)$ /%2?%{QUERY_STRING}&set_lang=%1 [L] # put 'www' as subdomain if none is given RewriteCond %{HTTP_HOST} ^([^\.]+\.[^\.]+)$ [NC] RewriteRule ^(.*)$ http://www.%1/$1 [L,R=301] # rewrite subdomain RewriteCond %{HTTP_HOST} ^(admin|files)\.[^\.]+\.[^\.]+$ [NC] RewriteCond %{REQUEST_URI} !^/_(admin|files)/ [NC] RewriteRule ^(.*)$ /_%1/$1 [L] # redirect to subdomain RewriteCond %{HTTP_HOST} ^www\.([^\.]+\.[^\.]+)$ [NC] RewriteRule ^_([^/]+)/ http://$1.%1/ [L,R=301] # start SSL on 'secure' subdomain if not started RewriteCond %{HTTPS} !=on RewriteCond %{HTTP_HOST} ^(secure)\.([^\.]+\.[^\.]+)$ [NC] RewriteRule ^(.*)$ https://%1.%2/$1 [L,R=301] # rewrite 'secure' subdomain RewriteCond %{HTTP_HOST} ^(demo|secure)\.[^\.]+\.[^\.]+$ [NC] RewriteCond %{REQUEST_URI} !^/_secure/ [NC] RewriteRule ^(.*)$ /_secure/$1 [L] # rewrite 'api' subdomain RewriteCond %{HTTP_HOST} ^api\.[^\.]+\.[^\.]+$ [NC] RewriteCond %{REQUEST_URI} !^/_api/ [NC] RewriteRule ^(?:([^/]+)/)?(?:([^/]+)/)?(?:([^/]+)/)?(?:([^/]+)/)?(?:([^/]+)/)?(?:([^/]+)/)? /_api/?%{QUERY_STRING}&v=$1&i=$2&k=$3&a=$4&t=$5&f=$6 [L] # redirect non-active subdomain to 'www' RewriteCond %{HTTP_HOST} !^(admin|api|demo|files|secure|www)\.([^\.]+\.[^\.]+)$ [NC] RewriteRule ^(.*)$ http://www.domain.com [L,R=301] # hide file extensions RewriteCond %{HTTP_HOST} ^www\. [NC] RewriteCond %{REQUEST_FILENAME} !-d RewriteCond %{REQUEST_FILENAME} !\.php$ [NC] RewriteCond %{REQUEST_URI} ^/([^/]*)/(?:([^/]*)/)?(?:([^/]*)/)?$ [NC] RewriteRule ^(.*)$ /%1.php?%{QUERY_STRING}&subpage=%2&subsection=%3 [L]

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  • Is my motherboard failing, or is there some other issue?

    - by ThatGuy
    So, several months ago I put together my own desktop PC. I set up a dual boot to Windows and Ubuntu. Recently, without changing any settings or installing anything new, the wifi stopped working on windows (I use a wifi adapter). It said it was connected, Network settings showed that it was working and running trouble shooting had no results. My internet still works on any other device. I found that removing the adapter from the motherboard and plugging it back in was the only thing that fixed the problem. Reinstalling the wifi drivers did not help. I purchased a new Wifi adapter, but the problem persists. More recently, I had a much more discouraging development. Sometimes, turning on the computer results in a boot loop: BIOS never starts. Instead, the monitor turns on as if it got a signal, then immediately turns off. This loops on it's own indefinitely until I hold down power, hard reset it, and try again. Sometimes it works, sometimes it doesn't. I haven't tested much on the Ubuntu side. It appears that wifi works at least some of the time, but since I've had issues just getting to BIOS I'm not confident the issue is on the software side. I've also noticed issues with some of the USB ports no longer working, but that seems to be off and on. Finally, as of a few minutes ago, I booted to windows to discover that everything was running very slowly. Slow here is a relative word, but I have a Samsung 840 pro SSD and I'm used to applications running nigh instantly, and it was a solid 3 minutes before any of my applications would load. Anyway, my question is this: Is it likely that my motherboard is failing? Either way, what steps can I take to try and pin down the problem and figure out what to do?

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  • Video adapter problem on new motherboard

    - by Dmitriy Matveev
    Something bad happened to my PC several days ago. I wasn't near my PC, so I have no idea about what happened it was just halted. When I tried to boot it was entering infinite loops of a few seconds power up (cpu, hdds, etc) and then power down. I've tried to boot the system with no additional components (that includes hdd, video, network adapters and even memory) connected and that didn't solved the problem, so I've made a decision that most likely it's either some a problem with power unit or with motherboard. I've tried to replace my power unit by another one (which was expected to be working) and the problem didn't resolved again. I've bought a new MB (ASUS P5KPL-AM SE) and tried to get it running with my old CPU and memory (I hope it's still alive). Since this MB include on-board video I've tried to run the PC without installation of mine video. The PC wasn't running and the BIOS was beeping one long signal following by two short (Does it means a video problem?). After that I've installed my video adapter to PCI-E slot and tried to boot the system again and the BIOS was beeping the same. I don't get it. I may expect some problem with CPU and/or memory since I don't know what happened to my PC (maybe some power failure or something different), but not with video and not with on-board video on newly bought MB. How can I understand what's wrong with my system now?

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  • Can you see something wrong in my working .htaccess?

    - by AlexV
    OK, after many search, trial and errors I've managed to create an .htaccess that do what I wanted (see explanations and questions after the code block): <IfModule mod_rewrite.c> RewriteEngine On #1 If the requested file is not url-mapper.php (to avoid .htaccess loop) RewriteCond %{REQUEST_FILENAME} (?<!url-mapper\.php)$ #2 If the requested URI does not end with an extension OR if the URI ends with .php* RewriteCond %{REQUEST_URI} !\.(.*) [OR] RewriteCond %{REQUEST_URI} \.php.*$ [NC] #3 If the requested URI is not in an excluded location RewriteCond %{REQUEST_URI} !^/seo-urls\/(excluded1|excluded2)(/.*)?$ #Then serve the URI via the mapper RewriteRule .* /seo-urls/url-mapper.php?uri=%{REQUEST_URI} [L,QSA] </IfModule> This is what the .htaccess should do: #1 is checking that the file requested is not url-mapper.php (to avoid infinite redirect loops). This file will always be at the root of the domain. #2 the .htaccess must only catch URLs that don't end with an extension (www.foo.com -- catch | www.foo.com/catch-me -- catch | www.foo.com/dont-catch.me -- don't catch) and URLs ending with .php* files (.php, .php4, .php5, .php123...). #3 some directories (and childs) can be excluded from the .htaccess (in this case /seo-urls/excluded1 and /seo-urls/excluded2). Finally the .htaccess feed the mapper with an hidden GET parameter named uri containing the requested uri. Even if I tested and everything works, I want to know if what I do is correct (and if it's the "best" way to do it). I've learned a lot with this "project" but I still consider myself a beginner at .htaccess and regular expressions so I want to triple check it there before putting it in production...

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  • Non-volatile cache RAID controllers: what kind of protection is there against NVCACHE failure?

    - by astrostl
    The battery back-up (BBU) model: admin enables write-back cache with BBU writes are cached to the RAID controller's RAM (major performance benefit) the battery saves uncommitted and cached data in the event of a power loss (reliability) If I lose power and come back within a day or so, my data should be both complete and uncorrupted. The downside to this is that, if the battery is dead or low, OR EVEN IF IT IS IN A RELEARN CYCLE (drain/charge loops to ensure the battery's health), the controller reverts to write-through mode and performance will suffer. What's more, the relearn cycles are usually automated on a schedule which may or may not happen in the middle of big traffic. So, that has to be manually disabled and manually scheduled for off-hours if it's a concern. Annoying either way. NV caches have capacitors with a sufficient charge to commit any uncommitted-to-disk data to flash. Not only is that more survivable in longer loss situations, but you don't have to concern yourself with battery death, wear-out, or relearning. All of that sounds great to me. What doesn't sound great to me is the prospect of that flash module having an issue, though. What if it's completely hosed? What if it's only partially hosed? A bit corrupted at the edges? Relearn cycles can tell when something like a simple battery is failing, but is there a similar process to verify that the flash is functional? I'm just far more trusting of a battery, warts and all. I know the card's RAM can fail, the card itself can fail - that's common territory, though. In case you didn't guess, yeah, I've experienced a shocking-to-me amount of flash/SSD/etc. failure :)

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  • Monitor programs accessing my keyboard?

    - by Anti Earth
    As of a few days ago, my computer is behaving 'erratically'. When I am typing, my pointer will randomly move to another place in the text and start typing a semi-random string of characters. ("gvyfn" is common; It has typed this about 8 times whilst I composed all the text above) It often highlights part of or all the text and overwrites it. It sometimes goes into loops of pressing Control-alt-delete down, bringing up Windows 7 menu thing. It sometimes even messes with mouseclicks; they have unexpected results, like requesting admin priveledges from applications, instead of switching to their window. I believe this is because it is holding a alt-function key down. This behaviour happens periodically, in waves. It might subside for an hour, then continue to haunt me. I believe it to be a virus or malicious program. My anti-virus (Symantec) and multiply MS rootkit removers could not find anything suspicious. I've noticed that sometimes it re-maps keys, and types gibberish when I press certain keys (though no pattern is evident). I believe a malicious program has installed a keyhook on my computer. I'm wondering... - Is there a way to let me view which programs are emulating keystrokes? - Is there a way to view what keyboard hooks are installed? (I'm also at liberty to try any other techniques to remove this blasted thing. It is easily the most fustrating computer problem I've encountered). Thanks!

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  • Speed up SQL Server queries with PREFETCH

    - by Akshay Deep Lamba
    Problem The SAN data volume has a throughput capacity of 400MB/sec; however my query is still running slow and it is waiting on I/O (PAGEIOLATCH_SH). Windows Performance Monitor shows data volume speed of 4MB/sec. Where is the problem and how can I find the problem? Solution This is another summary of a great article published by R. Meyyappan at www.sqlworkshops.com.  In my opinion, this is the first article that highlights and explains with working examples how PREFETCH determines the performance of a Nested Loop join.  First of all, I just want to recall that Prefetch is a mechanism with which SQL Server can fire up many I/O requests in parallel for a Nested Loop join. When SQL Server executes a Nested Loop join, it may or may not enable Prefetch accordingly to the number of rows in the outer table. If the number of rows in the outer table is greater than 25 then SQL will enable and use Prefetch to speed up query performance, but it will not if it is less than 25 rows. In this section we are going to see different scenarios where prefetch is automatically enabled or disabled. These examples only use two tables RegionalOrder and Orders.  If you want to create the sample tables and sample data, please visit this site www.sqlworkshops.com. The breakdown of the data in the RegionalOrders table is shown below and the Orders table contains about 6 million rows. In this first example, I am creating a stored procedure against two tables and then execute the stored procedure.  Before running the stored proceudre, I am going to include the actual execution plan. --Example provided by www.sqlworkshops.com --Create procedure that pulls orders based on City --Do not forget to include the actual execution plan CREATE PROC RegionalOrdersProc @City CHAR(20) AS BEGIN DECLARE @OrderID INT, @OrderDetails CHAR(200) SELECT @OrderID = o.OrderID, @OrderDetails = o.OrderDetails       FROM RegionalOrders ao INNER JOIN Orders o ON (o.OrderID = ao.OrderID)       WHERE City = @City END GO SET STATISTICS time ON GO --Example provided by www.sqlworkshops.com --Execute the procedure with parameter SmallCity1 EXEC RegionalOrdersProc 'SmallCity1' GO After running the stored procedure, if we right click on the Clustered Index Scan and click Properties we can see the Estimated Numbers of Rows is 24.    If we right click on Nested Loops and click Properties we do not see Prefetch, because it is disabled. This behavior was expected, because the number of rows containing the value ‘SmallCity1’ in the outer table is less than 25.   Now, if I run the same procedure with parameter ‘BigCity’ will Prefetch be enabled? --Example provided by www.sqlworkshops.com --Execute the procedure with parameter BigCity --We are using cached plan EXEC RegionalOrdersProc 'BigCity' GO As we can see from the below screenshot, prefetch is not enabled and the query takes around 7 seconds to execute. This is because the query used the cached plan from ‘SmallCity1’ that had prefetch disabled. Please note that even if we have 999 rows for ‘BigCity’ the Estimated Numbers of Rows is still 24.   Finally, let’s clear the procedure cache to trigger a new optimization and execute the procedure again. DBCC freeproccache GO EXEC RegionalOrdersProc 'BigCity' GO This time, our procedure runs under a second, Prefetch is enabled and the Estimated Number of Rows is 999.   The RegionalOrdersProc can be optimized by using the below example where we are using an optimizer hint. I have also shown some other hints that could be used as well. --Example provided by www.sqlworkshops.com --You can fix the issue by using any of the following --hints --Create procedure that pulls orders based on City DROP PROC RegionalOrdersProc GO CREATE PROC RegionalOrdersProc @City CHAR(20) AS BEGIN DECLARE @OrderID INT, @OrderDetails CHAR(200) SELECT @OrderID = o.OrderID, @OrderDetails = o.OrderDetails       FROM RegionalOrders ao INNER JOIN Orders o ON (o.OrderID = ao.OrderID)       WHERE City = @City       --Hinting optimizer to use SmallCity2 for estimation       OPTION (optimize FOR (@City = 'SmallCity2'))       --Hinting optimizer to estimate for the currnet parameters       --option (recompile)       --Hinting optimize not to use histogram rather       --density for estimation (average of all 3 cities)       --option (optimize for (@City UNKNOWN))       --option (optimize for UNKNOWN) END GO Conclusion, this tip was mainly aimed at illustrating how Prefetch can speed up query execution and how the different number of rows can trigger this.

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  • Code is not the best way to draw

    - by Bertrand Le Roy
    It should be quite obvious: drawing requires constant visual feedback. Why is it then that we still draw with code in so many situations? Of course it’s because the low-level APIs always come first, and design tools are built after and on top of those. Existing design tools also don’t typically include complex UI elements such as buttons. When we launched our Touch Display module for Netduino Go!, we naturally built APIs that made it easy to draw on the screen from code, but very soon, we felt the limitations and tedium of drawing in code. In particular, any modification requires a modification of the code, followed by compilation and deployment. When trying to set-up buttons at pixel precision, the process is not optimal. On the other hand, code is irreplaceable as a way to automate repetitive tasks. While tools like Illustrator have ways to repeat graphical elements, they do so in a way that is a little alien and counter-intuitive to my developer mind. From these reflections, I knew that I wanted a design tool that would be structurally code-centric but that would still enable immediate feedback and mouse adjustments. While thinking about the best way to achieve this goal, I saw this fantastic video by Bret Victor: The key to the magic in all these demos is permanent execution of the code being edited. Whenever a parameter is being modified, everything is re-executed immediately so that the impact of the modification is instantaneously visible. If you do this all the time, the code and the result of its execution fuse in the mind of the user into dual representations of a single object. All mental barriers disappear. It’s like magic. The tool I built, Nutshell, is just another implementation of this principle. It manipulates a list of graphical operations on the screen. Each operation has a nice editor, and translates into a bit of code. Any modification to the parameters of the operation will modify the bit of generated code and trigger a re-execution of the whole program. This happens so fast that it feels like the drawing reacts instantaneously to all changes. The order of the operations is also the order in which the code gets executed. So if you want to bring objects to the front, move them down in the list, and up if you want to move them to the back: But where it gets really fun is when you start applying code constructs such as loops to the design tool. The elements that you put inside of a loop can use the loop counter in expressions, enabling crazy scenarios while retaining the real-time edition features. When you’re done building, you can just deploy the code to the device and see it run in its native environment: This works thanks to two code generators. The first code generator is building JavaScript that is executed in the browser to build the canvas view in the web page hosting the tool. The second code generator is building the C# code that will run on the Netduino Go! microcontroller and that will drive the display module. The possibilities are fascinating, even if you don’t care about driving small touch screens from microcontrollers: it is now possible, within a reasonable budget, to build specialized design tools for very vertical applications. Direct feedback is a powerful ally in many domains. Code generation driven by visual designers has become more approachable than ever thanks to extraordinary JavaScript libraries and to the powerful development platform that modern browsers provide. I encourage you to tinker with Nutshell and let it open your eyes to new possibilities that you may not have considered before. It’s open source. And of course, my company, Nwazet, can help you develop your own custom browser-based direct feedback design tools. This is real visual programming…

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  • Silverlight Cream for December 13, 2010 -- #1010

    - by Dave Campbell
    In this Issue: Rénald Nollet, Benjamin Gavin, Dennis Doomen, Tim Greenfield, Mike Taulty, Jeff Blankenburg, Michael Crump, Laurent Duveau, Dragos Manolescu, KeyboardP, Yochay Kiriaty. Above the Fold: Silverlight: "Silverlight RIA Services and Basic, Anonymous Authentication" Benjamin Gavin WP7: "lving Circular Navigation in Windows Phone Silverlight Applications" Yochay Kiriaty SQL Azure: "SQL Azure Database Manager – Part 1 : How to connect to your SQL Azure DB" Rénald Nollet Shoutouts: Yochay Kiriaty has a post up on the Windows Phone Devloper Blog about open source (MSPL) projects helping WP7 devs: Windows Phone Recipes – Helping the Community Jesse Liberty's latest Yet Another Podcast is up and thie time it's Joe Stagner: Yet Another Podcast #18 – Joe Stagner Josh Schwartzberg sent me this link to what is apparently his yearly web-only rock Christmas album: MetalXmas... done in Silverlight and RIA Services From SilverlightCream.com: SQL Azure Database Manager – Part 1 : How to connect to your SQL Azure DB Rénald Nollet posted Part 1 of a series on a SQL Azure database manager all in Silverlight... has a live demo running, some description, and is making us wait for the next part! Silverlight RIA Services and Basic, Anonymous Authentication Benjamin Gavin has a quick post up resolving a basic RIA Services problem that I bet a lot of folks are looking for the answer on... like 500 series errors... cool little find he ferreted out... A night of Silverlight, WPF, unit testing and Caliburn Micro Dennis Doomen in concert with his employer gave a couple talks at the local DotNED user group, and covered literally a cornucopia of topics... slides, and example code for both talks... lotsa material here... Tim Greenfield on PuzzleTouch WP7 Application Tim Greenfield is the latest WP7 app developer to be interviewed by the SilverlightShow crew... lots of interesting comments and insight from Tim. Rebuilding the PDC 2010 Silverlight Application (Part 4) Mike Taulty has part 4 of his PDC 2010 Silverlight app construction project up and is taking the app into Blend, and the considerations that brought to the table. What I Learned In WP7 – Issue #2 Jeff Blankenburg continues his "What I Learned" series with this discussion about fonts, the Non-Linear Navigation service I mention below, and possible WP7 jobs. Part 3 of 4 : Tips/Tricks for Silverlight Developers Michael Crump has Part 3 of his Tips/Tricks up today. Lots of goodies this time: underlining in a TextBlock, getting browser info, startup params, VisualTreeHelper, and child windows. My Windows Phone 7 presentation in Montreal Laurent Duveau gave a WP7 presentation in Montreal as part of the Microsoft Windows Phone 7 Developer's Briefing, and has posted his materials and slide deck WP7 Code: Mocking Event Streams with IEnumerable Dragos Manolescu has a very cool post up on using IEnumerable to Mock event streams by leveraging the IObservable/IEnumerable duality, and uses the 2D bubble app that you can run and test in the emulator without needing an accelerometer Transparent Wallpapers – Video Tutorial KeyboardP has had so many queries about his Transparent wallpaper for WP7 that he produced a video tutorial for it... Solving Circular Navigation in Windows Phone Silverlight Applications Yochay Kiriaty discusses the first recipe they are releasing ... see the shoutout above, a Nonlinear Navigation Service ... to help with apps that have loops in navigation. Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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  • Old School Wizardry Tip: Batch File Comments

    - by jkauffman
    Johnny, the Endangered Keyboard-Driven Windows User Some of my proudest, obscure Windows tricks are losing their relevance. I know I’m not alone. Keyboard shortcuts are going the way of the dodo. I used to induce fearful awe by slapping Ctrl+Shift+Esc in front of the lowly, pedestrian Windows users. No windows key on the keyboard? No problem: Ctrl+Esc. No menu key on the keyboard: Shift+F10. I am also firmly planted in the habit of closing windows with the Alt+Space menu (Alt+Space, C); and I harbor a brooding, slow=growing list of programs that fail to support this correctly (that means you, Paint.NET). Every time a new version of windows comes out, the support for some of these minor time-saving habits get pared out. Will I complain publicly? Nope, I know my old ways should be axed to conserve precious design energy. In fact, I disapprove of fierce un-intuitiveness for the sake of alleged productivity. Like vim, for example. If you approach a program after being away for 5 years, having to recall encyclopedic knowledge is a flaw. The RTFM disciples have lost. Anyway, some of the items in my arsenal of goofy time-saving tricks are still relevant today. I wanted to draw attention to one that’s stood the test of time. Remember Batch Files? Yes, it’s true, batch files are fading faster than the world of print. But they're not dead yet. I still run into some situations where I opt to use batch files. They are still relevant for build processes, or just various development workflow tools. Sure, there’s powershell, but there’s that stupid Set-ExecutionPolicy speed bump standing in your way; can you really spare the time to A) hunt down that setting on all machines affected and/or B) make futile efforts to convince your coworkers/boss that the hassle was worth it? When possible, I prefer the batch file wild card. And whenever I return to batch files, I end up researching some of the unintuitive aspects such as parameters, quote handling, and ERRORLEVEL. But I never have to remember to use “REM” for comment lines, because there’s a cleaner way to do them! Double Colon For Eye-Friendly Comments Here is a very simple batch file, with pretty much minimal content: @ECHO OFF SETLOCAL REM This is a comment ECHO This batch file doesn’t do much If you code on a daily basis, this may be more suitable to your eyes: @ECHO OFF SETLOCAL :: This is a comment ECHO This batch file doesn’t do much Works great! I imagine I find it preferable due to the similarity to comments in other situations: // or ;  or # I’ve often make visual pseudo-line breaks in my code, and this colon-based syntax works wonders: @ECHO OFF SETLOCAL :: Do stuff ECHO Doing Stuff :::::::::::::::::::::::::::: :: Do more stuff ECHO This batch file doesn’t do much Not only is it more readable, but there’s a slight performance benefit. The batch file engine sees this as an invalid line label and immediately reads the following line. Use that fact to your advantage if this trick leads you into heated nerd debate. Two Pitfalls to Avoid Be aware of that there are a couple situations where this hack will fail you. It most likely won’t be a problem unless you’re getting really sophisticated with your batch files. Pitfall #1: Inline comments @ECHO OFF SETLOCAL IF EXIST C:\SomeFile.txt GOTO END ::This will fail :END Unfortunately, this fails. You can only have whitespace to the left of your comments. Pitfall #2: Code Blocks @ECHO OFF SETLOCAL IF EXIST C:\SomeFile.txt (         :: This will fail         ECHO HELLO ) Code blocks, such as if statements and for loops, cannot contain these comments. This is ultimately due to the fact that entire code blocks are processed as a single line. I originally learned this from Rob van der Woude’s site. He goes into more depth about the behavior of the pitfalls as well, if you are interested in further details. I hope this trick earns you serious geek rep!

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  • javascript complex recurrsion [on hold]

    - by Achilles
    Given Below is my data in data array. What i am doing in code below is that from that given data i have to construct json in a special format which i also gave below. //code start here var hierarchy={}; hierarchy.name="Hierarchy"; hierarchy.children=[{"name":"","children":[{"name":"","children":[]}]}]; var countryindex; var flagExist=false; var data = [ {country :"America", city:"Kansas", employe:'Jacob'}, {country :"Pakistan", city:"Lahore", employe:'tahir'}, {country :"Pakistan", city:"Islamabad", employe:'fakhar'} , {country :"Pakistan", city:"Lahore", employe:'bilal'}, {country :"India", city:"d", employe:'ali'} , {country :"Pakistan", city:"Karachi", employe:'eden'}, {country :"America", city:"Kansas", employe:'Jeen'} , {country :"India", city:"Banglore", employe:'PP'} , {country :"India", city:"Banglore", employe:'JJ'} , ]; for(var i=0;i<data.length;i++) { for(var j=0;j<hierarchy.children.length;j++) { //for checking country match if(hierarchy.children[j].name==data[i].country) { countryindex=j; flagExist=true; break; } } if(flagExist)//country match now no need to add new country just add city in it { var cityindex; var cityflag=false; //hierarchy.children[countryindex].children.push({"name":data[i].city,"children":[]}) //if(hierarchy.children[index].children!=undefined) for(var k=0;k< hierarchy.children[countryindex].children.length;k++) { //for checking city match if(hierarchy.children[countryindex].children[k].name==data[i].city) { // hierarchy.children[countryindex].children[k].children.push({"name":data[i].employe}) cityflag=true; cityindex=k; break; } } if(cityflag)//city match now add just empolye at that city index { hierarchy.children[countryindex].children[cityindex].children.push({"name":data[i].employe}); cityflag=false; } else//no city match so add new with employe also as this is new city so its emplye will be 1st { hierarchy.children[countryindex].children.push({"name":data[i].city,children:[{"name":data[i].employe}]}); //same as above //hierarchy.children[countryindex].children[length-1].children.push({"name":data[i].employe}); } flagExist=false; } else{ //no country match adding new country //with city also as this is new city of new country console.log("sparta"); hierarchy.children.push({"name":data[i].country,"children":[{"name":data[i].city,"children":[{"name":data[i].employe}]}]}); // hierarchy.children.children.push({"name":data[i].city,"children":[]}); } //console.log(hierarchy); } hierarchy.children.shift(); var j=JSON.stringify(hierarchy); //code ends here //here is the json which i seccessfully formed from the code { "name":"Hierarchy", "children":[ { "name":"America", "children":[ { "name":"Kansas", "children":[{"name":"Jacob"},{"name":"Jeen"}]}]}, { "name":"Pakistan", "children":[ { "name":"Lahore", "children": [ {"name":"tahir"},{"name":"bilal"}]}, { "name":"Islamabad", "children":[{"name":"fakhar"}]}, { "name":"Karachi", "children":[{"name":"eden"}]}]}, { "name":"India", "children": [ { "name":"d", "children": [ {"name":"ali"}]}, { "name":"Banglore", "children":[{"name":"PP"},{"name":"JJ"}]}]}]} Now the orignal problem is that currently i am solving this problem for data of array of three keys and i have to go for 3 nested loops now i want to optimize this solution so that if data array of object has more than 3 key say 5 {country :"America", state:"NewYork",city:"newYOrk",street:"elm", employe:'Jacob'}, or more than my solution will not work and i cannot decide before how many keys will come so i thought recursion may suit best here. But i am horrible in writing recurrsion and the case is also complex. Can some awesome programmer help me writing recurrsion or suggest some other solution.

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  • Code Contracts: validating arrays and collections

    - by DigiMortal
    Validating collections before using them is very common task when we use built-in generic types for our collections. In this posting I will show you how to validate collections using code contracts. It is cool how much awful looking code you can avoid using code contracts. Failing code Let’s suppose we have method that calculates sum of all invoices in collection. We have class Invoice and one of properties it has is Sum. I don’t introduce here any complex calculations on invoices because we have another problem to solve in this topic. Here is our code. public static decimal CalculateTotal(IList<Invoice> invoices) {     var sum = invoices.Sum(p => p.Sum);     return sum; } This method is very simple but it fails when invoices list contains at least one null. Of course, we can test if invoice is null but having nulls in lists like this is not good idea – it opens green way for different coding bugs in system. Our goal is to react to bugs ASAP at the nearest place they occur. There is one more way how to make our method fail. It happens when invoices is null. I thing it is also one common bugs during development and it even happens in production environments under some conditions that are usually hardly met. Now let’s protect our little calculation method with code contracts. We need two contracts: invoices cannot be null invoices cannot contain any nulls Our first contract is easy but how to write the second one? Solution: Contract.ForAll Preconditions in code are checked using Contract.Ensures method. This method takes boolean value as argument that sais if contract holds or not. There is also method Contract.ForAll that takes collection and predicate that must hold for that collection. Nice thing is ForAll returns boolean. So, we have very simple solution. public static decimal CalculateTotal(IList<Invoice> invoices) {     Contract.Requires(invoices != null);     Contract.Requires(Contract.ForAll<Invoice>(invoices, p => p != null));       var sum = invoices.Sum(p => p.Sum);     return sum; } And here are some lines of code you can use to test the contracts quickly. var invoices = new List<Invoice>(); invoices.Add(new Invoice()); invoices.Add(null); invoices.Add(new Invoice()); //CalculateTotal(null); CalculateTotal(invoices); If your code is covered with unit tests then I suggest you to write tests to check that these contracts hold for every code run. Conclusion Although it seemed at first place that checking all elements in collection may end up with for-loops that does not look so nice we were able to solve our problem nicely. ForAll method of contract class offered us simple mechanism to check collections and it does it smoothly the code-contracts-way. P.S. I suggest you also read devlicio.us blog posting Validating Collections with Code Contracts by Derik Whittaker.

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  • Changes in Language Punctuation [closed]

    - by Wes Miller
    More social curiosity than actual programming question... (I got shot for posting this on Stack Overflow. They sent me here. At least i hope here is where they meant.) Based on the few responses I got before the content police ran me off Stack Overflow, I should note that I am legally blind and neatness and consistency in programming are my best friends. A thousand years ago when I took my first programming class (Fortran 66) and a mere 500 years ago when I tokk my first C and C++ classes, there were some pretty standard punctuation practices across languages. I saw them in Basic (shudder), PL/1, PL/AS, Rexx even Pascal. Ok, APL2 is not part of this discussion. Each language has its own peculiar punctuation. Pascal's periods, Fortran's comma separated do loops, almost everybody else's semicolons. As I learned it, each language also has KEYWORDS (if, for, do, while, until, etc.) which are set off by whitespace (or the left margin) if, etc. Each language has function, subroutines of whatever they're called. Some built-in some user coded. They were set off by function_name( parameters );. As in sqrt( x ) or rand( y ); Lately, there seems to be a new set of punctuation rules. Especially in c++ where initializers get glued onto the end of variable declarations int x(0); or auto_ptr p(new gizmo); This usually, briefly fools me into thinking someone is declaring a function prototype or using a function as a integer. Then "if" and 'for' seems to have grown parens; if(true) for(;;), etc. Since when did keywords become functions. I realize some people think they ARE functions with iterators as parameters. But if "for" is a function, where did the arg separating commas go? And finally, functions seem to have shed their parens; sqrt (2) select (...) I know, I koow, loosening whitespace rules is good. Keep reading. Question: when did the old ways disappear and this new way come into vogue? Does anyone besides me find it irritating to read and that the information that the placement of punctuation used to convey is gone? I know full well that K&R put the { at the end of the "if" or "for" to save a byte here and there. Can't use that excuse here. Space as an excuse for loss of readability died as HDD space soared past 100 MiB. Your thoughts are solicited. If there is a good reason to do this, I'll gladly learn it and maybe in another 50 years I'll get used to it. Of course it's good that compilers recognize these (IMHO) typos and keep right on going, but just because you CAN code it that way doesn't mean you HAVE to, right?

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  • Octree subdivision problem

    - by ChaosDev
    Im creating octree manually and want function for effectively divide all nodes and their subnodes - For example - I press button and subnodes divided - press again - all subnodes divided again. Must be like - 1 - 8 - 64. The problem is - i dont understand how organize recursive loops for that. OctreeNode in my unoptimized implementation contain pointers to subnodes(childs),parent,extra vector(contains dublicates of child),generation info and lots of information for drawing. class gOctreeNode { //necessary fields gOctreeNode* FrontBottomLeftNode; gOctreeNode* FrontBottomRightNode; gOctreeNode* FrontTopLeftNode; gOctreeNode* FrontTopRightNode; gOctreeNode* BackBottomLeftNode; gOctreeNode* BackBottomRightNode; gOctreeNode* BackTopLeftNode; gOctreeNode* BackTopRightNode; gOctreeNode* mParentNode; std::vector<gOctreeNode*> m_ChildsVector; UINT mGeneration; bool mSplitted; bool isSplitted(){return m_Splitted;} .... //unnecessary fields }; DivideNode of Octree class fill these fields, set mSplitted to true, and prepare for correctly drawing. Octree contains basic nodes(m_nodes). Basic node can be divided, but now I want recursivly divide already divided basic node with 8 subnodes. So I write this function. void DivideAllChildCells(int ix,int ih,int id) { std::vector<gOctreeNode*> nlist; std::vector<gOctreeNode*> dlist; int index = (ix * m_Height * m_Depth) + (ih * m_Depth) + (id * 1);//get index of specified node gOctreeNode* baseNode = m_nodes[index].get(); nlist.push_back(baseNode->FrontTopLeftNode); nlist.push_back(baseNode->FrontTopRightNode); nlist.push_back(baseNode->FrontBottomLeftNode); nlist.push_back(baseNode->FrontBottomRightNode); nlist.push_back(baseNode->BackBottomLeftNode); nlist.push_back(baseNode->BackBottomRightNode); nlist.push_back(baseNode->BackTopLeftNode); nlist.push_back(baseNode->BackTopRightNode); bool cont = true; UINT d = 0;//additional recursive loop param (?) UINT g = 0;//additional recursive loop param (?) LoopNodes(d,g,nlist,dlist); //Divide resulting nodes for(UINT i = 0; i < dlist.size(); i++) { DivideNode(dlist[i]); } } And now, back to the main question,I present LoopNodes, which must do all work for giving dlist nodes for splitting. void LoopNodes(UINT& od,UINT& og,std::vector<gOctreeNode*>& nlist,std::vector<gOctreeNode*>& dnodes) { //od++;//recursion depth bool f = false; //pass through childs for(UINT i = 0; i < 8; i++) { if(nlist[i]->isSplitted())//if node splitted and have childs { //pass forward through tree for(UINT j = 0; j < 8; j++) { nlist[j] = nlist[j]->m_ChildsVector[j];//set pointers to these childs } LoopNodes(od,og,nlist,dnodes); } else //if no childs { //add to split vector dnodes.push_back(nlist[i]); } } } This version of loop nodes works correctly for 2(or 1?) generations after - this will not divide neightbours nodes, only some corners. I need correct algorithm. Screenshot All I need - is correct version of LoopNodes, which can add all nodes for DivideNode.

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  • How do I cap rendering of tiles in a 2D game with SDL?

    - by farmdve
    I have some boilerplate code working, I basically have a tile based map composed of just 3 colors, and some walls and render with SDL. The tiles are in a bmp file, but each tile inside it corresponds to an internal number of the type of tile(color, or wall). I have pretty basic collision detection and it works, I can also detetc continuous presses, which allows me to move pretty much anywhere I want. I also have a moving camera, which follows the object. The problem is that, the tile based map is bigger than the resolution, thus not all of the map can be displayed on the screen, but it's still rendered. I would like to cap it, but since this is new to me, I pretty much have no idea. Although I cannot post all the code, as even though I am a newbie and the code pretty basic, it's already quite a few lines, I can post what I tried to do void set_camera() { //Center the camera over the dot camera.x = ( player.box.x + DOT_WIDTH / 2 ) - SCREEN_WIDTH / 2; camera.y = ( player.box.y + DOT_HEIGHT / 2 ) - SCREEN_HEIGHT / 2; //Keep the camera in bounds. if(camera.x < 0 ) { camera.x = 0; } if(camera.y < 0 ) { camera.y = 0; } if(camera.x > LEVEL_WIDTH - camera.w ) { camera.x = LEVEL_WIDTH - camera.w; } if(camera.y > LEVEL_HEIGHT - camera.h ) { camera.y = LEVEL_HEIGHT - camera.h; } } set_camera() is the function which calculates the camera position based on the player's positions. I won't pretend I know much about it. Rectangle box = {0,0,0,0}; for(int t = 0; t < TOTAL_TILES; t++) { if(box.x < (camera.x - TILE_WIDTH) || box.y > (camera.y - TILE_HEIGHT)) apply_surface(box.x - camera.x, box.y - camera.y, surface, screen, &clips[tiles[t]]); box.x += TILE_WIDTH; //If we've gone too far if(box.x >= LEVEL_WIDTH) { //Move back box.x = 0; //Move to the next row box.y += TILE_HEIGHT; } } This is basically my render code. The for loop loops over 192 tiles stored in an int array, each with their own unique value describing the tile type(wall or one of three possible colored tiles). box is an SDL_Rect containing the current position of the tile, which is calculated on render. TILE_HEIGHT and TILE_WIDTH are of value 80. So the cap is determined by if(box.x < (camera.x - TILE_WIDTH) || box.y > (camera.y - TILE_HEIGHT)) However, this is just me playing with the values and see what doesn't break it. I pretty much have no idea how to calculate it. My screen resolution is 1024/768, and the tile map is of size 1280/960.

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  • How to define template directives (from an API perspective)?

    - by Ralph
    Preface I'm writing a template language (don't bother trying to talk me out of it), and in it, there are two kinds of user-extensible nodes. TemplateTags and TemplateDirectives. A TemplateTag closely relates to an HTML tag -- it might look something like div(class="green") { "content" } And it'll be rendered as <div class="green">content</div> i.e., it takes a bunch of attributes, plus some content, and spits out some HTML. TemplateDirectives are a little more complicated. They can be things like for loops, ifs, includes, and other such things. They look a lot like a TemplateTag, but they need to be processed differently. For example, @for($i in $items) { div(class="green") { $i } } Would loop over $items and output the content with the variable $i substituted in each time. So.... I'm trying to decide on a way to define these directives now. Template Tags The TemplateTags are pretty easy to write. They look something like this: [TemplateTag] static string div(string content = null, object attrs = null) { return HtmlTag("div", content, attrs); } Where content gets the stuff between the curly braces (pre-rendered if there are variables in it and such), and attrs is either a Dictionary<string,object> of attributes, or an anonymous type used like a dictionary. It just returns the HTML which gets plunked into its place. Simple! You can write tags in basically 1 line. Template Directives The way I've defined them now looks like this: [TemplateDirective] static string @for(string @params, string content) { var tokens = Regex.Split(@params, @"\sin\s").Select(s => s.Trim()).ToArray(); string itemName = tokens[0].Substring(1); string enumName = tokens[1].Substring(1); var enumerable = data[enumName] as IEnumerable; var sb = new StringBuilder(); var template = new Template(content); foreach (var item in enumerable) { var templateVars = new Dictionary<string, object>(data) { { itemName, item } }; sb.Append(template.Render(templateVars)); } return sb.ToString(); } (Working example). Basically, the stuff between the ( and ) is not split into arguments automatically (like the template tags do), and the content isn't pre-rendered either. The reason it isn't pre-rendered is because you might want to add or remove some template variables or something first. In this case, we add the $i variable to the template variables, var templateVars = new Dictionary<string, object>(data) { { itemName, item } }; And then render the content manually, sb.Append(template.Render(templateVars)); Question I'm wondering if this is the best approach to defining custom Template Directives. I want to make it as easy as possible. What if the user doesn't know how to render templates, or doesn't know that he's supposed to? Maybe I should pass in a Template instance pre-filled with the content instead? Or maybe only let him tamper w/ the template variables, and then automatically render the content at the end? OTOH, for things like "if" if the condition fails, then the template wouldn't need to be rendered at all. So there's a lot of flexibility I need to allow in here. Thoughts?

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  • DrawIndexedPrimitives overdraws data in previous buffer if called in loop

    - by Daniel Excinsky
    I doubled the question from stackoverflow here, and will delete the opposite of a question that gave me the answer. I have the Draw method in one of my renderers, that loops through the dictionary and gets precollected and preinitialized buffers. When dictionary has only one element, everything is just fine. But with more elements what I get on the screen is only the data from the last buffer (I suppose, not sure) My Draw method: public void Draw(GameTime gameTime) { if (!_areStaticEffectsSet) { // blockEffect.Parameters["TextureAtlas"].SetValue(textureAtlas); blockEffect.Parameters["HorizonColor"].SetValue(World.HORIZONCOLOR); blockEffect.Parameters["NightColor"].SetValue(World.NIGHTCOLOR); blockEffect.Parameters["MorningTint"].SetValue(World.MORNINGTINT); blockEffect.Parameters["EveningTint"].SetValue(World.EVENINGTINT); blockEffect.Parameters["SunColor"].SetValue(World.SUNCOLOR); _areStaticEffectsSet = true; } blockEffect.Parameters["World"].SetValue(Matrix.Identity); blockEffect.Parameters["View"].SetValue(_player.CameraView); blockEffect.Parameters["Projection"].SetValue(_player.CameraProjection); blockEffect.Parameters["CameraPosition"].SetValue(_player.CameraPosition); blockEffect.Parameters["timeOfDay"].SetValue(_world.TimeOfDay); var viewFrustum = new BoundingFrustum(_player.CameraView * _player.CameraProjection); _graphicsDevice.BlendState = BlendState.Opaque; _graphicsDevice.DepthStencilState = DepthStencilState.Default; foreach (KeyValuePair<int, Texture2D> textureAtlas in textureAtlases) { blockEffect.Parameters["TextureAtlas"].SetValue(textureAtlas.Value); foreach (EffectPass pass in blockEffect.CurrentTechnique.Passes) { pass.Apply(); //TODO: ?????????? ??????????????? ?? ?????? ?? ??????? ??????? VertexBuffer ? IndexBuffer foreach (Chunk chunk in _world.Chunks.Values) { if (chunk == null || chunk.IsDisposed) { continue; } if (chunk.BoundingBox.Intersects(viewFrustum) && chunk.GetBlockIndexBuffer(textureAtlas.Key) != null) { lock (chunk) { if (chunk.GetBlockIndexBuffer(textureAtlas.Key).IndexCount > 0) { VertexBuffer vertexBuffer = chunk.GetBlockVertexBuffer(textureAtlas.Key); IndexBuffer indexBuffer = chunk.GetBlockIndexBuffer(textureAtlas.Key); //if (chunk.DrawIndex == new Vector3i(0, 0, 0)) //{ //if (textureAtlas.Key == -1) //{ //var varray = new [] //{ //new VertexPositionTextureLight(new Vector3(0,68,0), new Vector2(0,1),1,new Vector3(0,0,0), new Vector3(1,1,1)), //new VertexPositionTextureLight(new Vector3(0,68,1), new Vector2(0,1),1,new Vector3(0,0,0), new Vector3(1,1,1)), //new VertexPositionTextureLight(new Vector3(1,68,0), new Vector2(0,1),1,new Vector3(0,0,0), new Vector3(1,1,1)) //}; //var iarray = new short[] {0, 1, 2}; //vertexBuffer = new VertexBuffer(_graphicsDevice, typeof(VertexPositionTextureLight), varray.Length, BufferUsage.WriteOnly); //indexBuffer = new IndexBuffer(_graphicsDevice, IndexElementSize.SixteenBits, iarray.Length, BufferUsage.WriteOnly); //vertexBuffer.SetData(varray); //indexBuffer.SetData(iarray); } } _graphicsDevice.SetVertexBuffer(vertexBuffer); _graphicsDevice.Indices = indexBuffer; _graphicsDevice.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, 0, vertexBuffer.VertexCount, 0, indexBuffer.IndexCount / 3); } } } } } } } Noteworthy things about the code: XNA version is 4.0. I've commented the debugging code in the loop, but left it for it may bring some insight. I try not only to change vertices/indices in the loop, but textureAtlas also. Code in the shader about textureAtlas: Texture TextureAtlas; sampler TextureAtlasSampler = sampler_state { texture = <TextureAtlas>; magfilter = POINT; minfilter = POINT; mipfilter = POINT; AddressU = WRAP; AddressV = WRAP; }; struct VSInput { float4 Position : POSITION0; float2 TexCoords1 : TEXCOORD0; float SunLight : COLOR0; float3 LocalLight : COLOR1; float3 Normal : NORMAL0; }; VertexPositionTextureLight is my own realization of IVertexType. So, do anybody know about this problem, or see the wrongness in my code (that's far more likely)?

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  • Introduction to WebCenter Personalization: &ldquo;The Conductor&rdquo;

    - by Steve Pepper
    There are some new faces in the town of WebCenter with the latest 11g PS3 release.  A new component has introduced itself as "Oracle WebCenter Personalization", a.k.a WCP, to simplify delivery of a personalized experience and content to end users.  This posting reviews one of the primary components within WCP: "The Conductor". The Conductor: This ain't just an ordinary cloud... One of the founding principals behind WebCenter Personalization was to provide an open client-side API that remains independent of the technology invoking it, in addition to independence from the architecture running it.  The Conductor delivers this, and much, much more. The Conductor is the engine behind WebCenter Personalization that allows flow-based documents, called "Scenarios", to be managed and executed on the server-side through a well published and RESTful api.      The Conductor also supports an extensible model for custom provider integration that can be easily invoked within a Scenario to promote seamless integration with existing business assets. Introducing the Scenario Conductor Scenarios are declarative offline-authored documents using the custom Personalization JDeveloper bundle included with WebCenter.  A Scenario contains one (or more) statements that can: Create variables that are scoped to the current execution context Iterate over collections, or loop until a specific condition is met Execute one or more statements when a condition is met Invoke other scenarios that exist within the same namespace Invoke a data provider that integrates with custom applications Once a variable is assigned within the Scenario's execution context, it can be referenced anywhere within the same Scenario using the common Expression Language syntax used in J2EE web containers. Scenarios are then published and tested to the Integrated WebLogic Server domain, or published remotely to other domains running WebCenter Personalization. Various Client-side Models The Conductor server API is built upon RESTful services that support a wide variety of clients able to communicate over HTTP.  The Conductor supports the following client-side models: REST:  Popular browser-based languages can be used to manage and execute Conductor Scenarios.  There are other public methods to retrieve configured provider metadata that can be used by custom applications. The Conductor currently supports XML and JSON for it's API syntax. Java: WebCenter Personalization delivers a robust and light-weight java client with the popular Jersey framework as it's foundation.  It has never been easier to write a remote java client to manage remote RESTful services. Expression Language (EL): Allow the results of Scenario execution to control your user interface or embed personalized content using the session-scoped managed bean.  The EL client can also be used in straight JSP pages with minimal configuration. Extensible Provider Framework The Conductor supports a pluggable provider framework for integrating custom code with Scenario execution.  There are two types of providers supported by the Conductor: Function Provider: Function Providers are simple java annotated classes with static methods that are meant to be served as utilities.  Some common uses would include: object creation or instantiation, data transformation, and the like.  Function Providers can be invoked using the common EL syntax from variable assignments, conditions, and loops. For example:  ${myUtilityClass:doStuff(arg1,arg2))} If you are familiar with EL Functions, Function Providers are based on the same concept. Data Provider: Like Function Providers, Data Providers are annotated java classes, but they must adhere to a much more strict object model.  Data Providers have access to a wealth of Conductor services, such as: Access to namespace-scoped configuration API that can be managed by Oracle Enterprise Manager, Scenario execution context for expression resolution, and more.  Oracle ships with three out-of-the-box data providers that supports integration with: Standardized Content Servers(CMIS),  Federated Profile Properties through the Properties Service, and WebCenter Activity Graph. Useful References If you are looking to immediately get started writing your own application using WebCenter Personalization Services, you will find the following references helpful in getting you on your way: Personalizing WebCenter Applications Authoring Personalized Scenarios in JDeveloper Using Personalization APIs Externally Implementing and Calling Function Providers Implementing and Calling Data Providers

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  • The long road to bug-free software

    - by Tony Davis
    The past decade has seen a burgeoning interest in functional programming languages such as Haskell or, in the Microsoft world, F#. Though still on the periphery of mainstream programming, functional programming concepts are gradually seeping into the imperative C# language (for example, Lambda expressions have their root in functional programming). One of the more interesting concepts from functional programming languages is the use of formal methods, the lofty ideal behind which is bug-free software. The idea is that we write a specification that describes exactly how our function (say) should behave. We then prove that our function conforms to it, and in doing so have proved beyond any doubt that it is free from bugs. All programmers already use one form of specification, specifically their programming language's type system. If a value has a specific type then, in a type-safe language, the compiler guarantees that value cannot be an instance of a different type. Many extensions to existing type systems, such as generics in Java and .NET, extend the range of programs that can be type-checked. Unfortunately, type systems can only prevent some bugs. To take a classic problem of retrieving an index value from an array, since the type system doesn't specify the length of the array, the compiler has no way of knowing that a request for the "value of index 4" from an array of only two elements is "unsafe". We restore safety via exception handling, but the ideal type system will prevent us from doing anything that is unsafe in the first place and this is where we start to borrow ideas from a language such as Haskell, with its concept of "dependent types". If the type of an array includes its length, we can ensure that any index accesses into the array are valid. The problem is that we now need to carry around the length of arrays and the values of indices throughout our code so that it can be type-checked. In general, writing the specification to prove a positive property, even for a problem very amenable to specification, such as a simple sorting algorithm, turns out to be very hard and the specification will be different for every program. Extend this to writing a specification for, say, Microsoft Word and we can see that the specification would end up being no simpler, and therefore no less buggy, than the implementation. Fortunately, it is easier to write a specification that proves that a program doesn't have certain, specific and undesirable properties, such as infinite loops or accesses to the wrong bit of memory. If we can write the specifications to prove that a program is immune to such problems, we could reuse them in many places. The problem is the lack of specification "provers" that can do this without a lot of manual intervention (i.e. hints from the programmer). All this might feel a very long way off, but computing power and our understanding of the theory of "provers" advances quickly, and Microsoft is doing some of it already. Via their Terminator research project they have started to prove that their device drivers will always terminate, and in so doing have suddenly eliminated a vast range of possible bugs. This is a huge step forward from saying, "we've tested it lots and it seems fine". What do you think? What might be good targets for specification and verification? SQL could be one: the cost of a bug in SQL Server is quite high given how many important systems rely on it, so there's a good incentive to eliminate bugs, even at high initial cost. [Many thanks to Mike Williamson for guidance and useful conversations during the writing of this piece] Cheers, Tony.

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  • OpenGL Fast-Object Instancing Error

    - by HJ Media Studios
    I have some code that loops through a set of objects and renders instances of those objects. The list of objects that needs to be rendered is stored as a std::map, where an object of class MeshResource contains the vertices and indices with the actual data, and an object of classMeshRenderer defines the point in space the mesh is to be rendered at. My rendering code is as follows: glDisable(GL_BLEND); glEnable(GL_CULL_FACE); glDepthMask(GL_TRUE); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glEnable(GL_DEPTH_TEST); for (std::map<MeshResource*, std::vector<MeshRenderer*> >::iterator it = renderables.begin(); it != renderables.end(); it++) { it->first->setupBeforeRendering(); cout << "<"; for (unsigned long i =0; i < it->second.size(); i++) { //Pass in an identity matrix to the vertex shader- used here only for debugging purposes; the real code correctly inputs any matrix. uniformizeModelMatrix(Matrix4::IDENTITY); /** * StartHere fix rendering problem. * Ruled out: * Vertex buffers correctly. * Index buffers correctly. * Matrices correct? */ it->first->render(); } it->first->cleanupAfterRendering(); } geometryPassShader->disable(); glDepthMask(GL_FALSE); glDisable(GL_CULL_FACE); glDisable(GL_DEPTH_TEST); The function in MeshResource that handles setting up the uniforms is as follows: void MeshResource::setupBeforeRendering() { glEnableVertexAttribArray(0); glEnableVertexAttribArray(1); glEnableVertexAttribArray(2); glEnableVertexAttribArray(3); glEnableVertexAttribArray(4); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, iboID); glBindBuffer(GL_ARRAY_BUFFER, vboID); glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), 0); // Vertex position glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const GLvoid*) 12); // Vertex normal glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const GLvoid*) 24); // UV layer 0 glVertexAttribPointer(3, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const GLvoid*) 32); // Vertex color glVertexAttribPointer(4, 1, GL_UNSIGNED_SHORT, GL_FALSE, sizeof(Vertex), (const GLvoid*) 44); //Material index } The code that renders the object is this: void MeshResource::render() { glDrawElements(GL_TRIANGLES, geometry->numIndices, GL_UNSIGNED_SHORT, 0); } And the code that cleans up is this: void MeshResource::cleanupAfterRendering() { glDisableVertexAttribArray(0); glDisableVertexAttribArray(1); glDisableVertexAttribArray(2); glDisableVertexAttribArray(3); glDisableVertexAttribArray(4); } The end result of this is that I get a black screen, although the end of my rendering pipeline after the rendering code (essentially just drawing axes and lines on the screen) works properly, so I'm fairly sure it's not an issue with the passing of uniforms. If, however, I change the code slightly so that the rendering code calls the setup immediately before rendering, like so: void MeshResource::render() { setupBeforeRendering(); glDrawElements(GL_TRIANGLES, geometry->numIndices, GL_UNSIGNED_SHORT, 0); } The program works as desired. I don't want to have to do this, though, as my aim is to set up vertex, material, etc. data once per object type and then render each instance updating only the transformation information. The uniformizeModelMatrix works as follows: void RenderManager::uniformizeModelMatrix(Matrix4 matrix) { glBindBuffer(GL_UNIFORM_BUFFER, globalMatrixUBOID); glBufferSubData(GL_UNIFORM_BUFFER, 0, sizeof(Matrix4), matrix.ptr()); glBindBuffer(GL_UNIFORM_BUFFER, 0); }

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