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  • Why does defined(X) not work in a preprocessor definition without a space?

    - by Devin
    A preprocessor definition that includes defined(X) will never evaluate to true, but (defined X) will. This occurs in MSVC9; I have not tested other preprocessors. A simple example: #define FEATURE0 1 #define FEATURE1 0 #define FEATURE2 1 #define FEATURE3 (FEATURE0 && !FEATURE1 && (defined(FEATURE2))) #define FEATURE4 (FEATURE0 && !FEATURE1 && (defined FEATURE2)) #define FEATURE5 (FEATURE0 && !FEATURE1 && (defined (FEATURE2))) #if FEATURE3 #pragma message("FEATURE3 Enabled") #elif (FEATURE0 && !FEATURE1 && (defined(FEATURE2))) #pragma message("FEATURE3 Enabled (Fallback)") #endif #if FEATURE4 #pragma message("FEATURE4 Enabled") #elif (FEATURE0 && !FEATURE1 && (defined FEATURE2)) #pragma message("FEATURE4 Enabled (Fallback)") #endif #if FEATURE5 #pragma message("FEATURE5 Enabled") #elif (FEATURE0 && !FEATURE1 && (defined (FEATURE2))) #pragma message("FEATURE5 Enabled (Fallback)") #endif The output from the compiler is: 1FEATURE3 Enabled (Fallback) 1FEATURE4 Enabled 1FEATURE5 Enabled Working cases: defined (X), defined( X ), and defined X. Broken case: defined(X) Why is defined evaluated differently when part of a definition, as in the #if cases in the example, compared to direct evaluation, as in the #elif cases in the example?

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  • How to invoke a 64-bit app in a 32-bit process space?

    - by CTVerint
    Hi, in a 64-bit WinOS ennvironment, how can a 32-bit process/app such as CMD invoke a 64-bit app? For example, we have a 32-bit launcher (aka installation program). It needs to invoke a 64-bit 3rd party installer. Presently, doing so will render the OS to say it's not a Win32 App. If you know of any workaround or suggestion, I am all ears... thanks, CT

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  • CSS: Is it possible to have a 3-column layout with BOTH the left column and center column flexibly filling the space?

    - by Steven Lu
    It is possible to use position:absolute and left and right on the middle column to set where it ends in relation to the parent div. However I'd like to be able to have the left side of the center div to start right where the left column ends, and for the left column to be adjustable (based on its content). This seems like a really basic thing but from what I understand there is no way to do this without flexboxes. Is this true? Is there nothing I could do with clever nesting of semantically superfluous elements and certain styles set to auto?

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  • Inserting THEAD element into embedded HTML using jQuery

    - by robalot
    I'm trying to use jQuery to insert HTML into a table element. I've been messing variations of the selector (below) with no luck. Can someone help me? My Selector: $j('#ctl00_body_gridData_dom').children('table:first').append("<thead><tr><td colspan='6'>&nbsp;</td><td align='center' colspan='7'>EM SPECS</td><td align='center' colspan='7'>FISH</td><td colspan='11'>&nbsp;</td></tr></thead>"); Here's what I am trying to do... I want to insert this: <thead> <tr> <td colspan="6"> &nbsp; </td> <td align="center" colspan="7"> EM SPECS </td> <td align="center" colspan="7"> FISH </td> <td colspan="11"> &nbsp; </td> </tr> </thead> The sample below is what I want the end result to look like... So It Looks Like This: Jquery Event Pool <table id="ctl00_body_gridData" style="width: 2000px; -moz-user-select: none;" border="1" cellpadding="0" cellspacing="0"> <tbody> <tr> <td id="ctl00_body_gridData_dom" class="GridData" style="vertical-align: top; height: 245px;" valign="top"> <table style="width: 100%;" border="0" cellpadding="0" cellspacing="0"> <thead> <tr> <td colspan="6"> &nbsp; </td> <td align="center" colspan="7"> EM SPECS </td> <td align="center" colspan="7"> FISH </td> <td colspan="11"> &nbsp; </td> </tr> </thead> <tbody> <tr id="ctl00_body_gridData_top_head" class="headerlineGrid"> <td width="16"> <div style="width: 16px;"></div> </td> <td onclick="ctl00_body_gridData.ClickHandler(event,this,4,0)" ondblclick="ctl00_body_gridData.DblClickHandler(event,null,4,0)" onmousemove="ctl00_body_gridData.MoveHandler(event,this,0,0)" onmouseover="ctl00_body_gridData.OverHandler(event,this,0)" onmouseout="ctl00_body_gridData.OutHandler(event,this,0)" onmousedown="ctl00_body_gridData.DownHandler(event,this,4,0)" onmouseup="ctl00_body_gridData.UpHandler(event,this,4,0)" style="width: 89px;" class="HeadingCell" align="center"> <div style="text-align: center; overflow: hidden; width: 89px;"> <table width="100%" border="0" cellpadding="0" cellspacing="0"> <tbody> <tr> <td style="white-space: nowrap; text-align: center;" class="HeadingCellText" align="center"> Work<br>Package</td> </tr> </tbody> </table> </div> </td> <td onclick="ctl00_body_gridData.ClickHandler(event,this,6,0)" ondblclick="ctl00_body_gridData.DblClickHandler(event,null,6,0)" onmousemove="ctl00_body_gridData.MoveHandler(event,this,1,0)" onmouseover="ctl00_body_gridData.OverHandler(event,this,0)" onmouseout="ctl00_body_gridData.OutHandler(event,this,0)" onmousedown="ctl00_body_gridData.DownHandler(event,this,6,0)" onmouseup="ctl00_body_gridData.UpHandler(event,this,6,0)" style="width: 62px;" class="HeadingCell" align="center"> <div style="text-align: center; overflow: hidden; width: 62px;"> <table width="100%" border="0" cellpadding="0" cellspacing="0"> <tbody> <tr> <td style="white-space: nowrap; text-align: center;" class="HeadingCellText" align="center"> Work<br>Order</td> </tr> </tbody> </table> </div> </td> <td onclick="ctl00_body_gridData.ClickHandler(event,this,9,0)" ondblclick="ctl00_body_gridData.DblClickHandler(event,null,9,0)" onmousemove="ctl00_body_gridData.MoveHandler(event,this,2,0)" onmouseover="ctl00_body_gridData.OverHandler(event,this,0)" onmouseout="ctl00_body_gridData.OutHandler(event,this,0)" onmousedown="ctl00_body_gridData.DownHandler(event,this,9,0)" onmouseup="ctl00_body_gridData.UpHandler(event,this,9,0)" style="width: 66px;" class="HeadingCell" align="center"> <div style="text-align: center; overflow: hidden; width: 66px;"> <table width="100%" border="0" cellpadding="0" cellspacing="0"> <tbody> <tr> <td style="white-space: nowrap; text-align: center;" class="HeadingCellText" align="center"> FCR<br>Group</td> </tr> </tbody> </table> </div> </td> <td onclick="ctl00_body_gridData.ClickHandler(event,this,12,0)" ondblclick="ctl00_body_gridData.DblClickHandler(event,null,12,0)" onmousemove="ctl00_body_gridData.MoveHandler(event,this,3,0)" onmouseover="ctl00_body_gridData.OverHandler(event,this,0)" onmouseout="ctl00_body_gridData.OutHandler(event,this,0)" onmousedown="ctl00_body_gridData.DownHandler(event,this,12,0)" onmouseup="ctl00_body_gridData.UpHandler(event,this,12,0)" style="width: 105px;" class="HeadingCell" align="center"> <div style="text-align: center; overflow: hidden; width: 105px;"> <table width="100%" border="0" cellpadding="0" cellspacing="0"> <tbody> <tr> <td style="white-space: nowrap; text-align: center;" class="HeadingCellText" align="center">Contractor</td> </tr> </tbody> </table> </div> </td> <td onclick="ctl00_body_gridData.ClickHandler(event,this,15,0)" ondblclick="ctl00_body_gridData.DblClickHandler(event,null,15,0)" onmousemove="ctl00_body_gridData.MoveHandler(event,this,4,0)" onmouseover="ctl00_body_gridData.OverHandler(event,this,0)" onmouseout="ctl00_body_gridData.OutHandler(event,this,0)" onmousedown="ctl00_body_gridData.DownHandler(event,this,15,0)" onmouseup="ctl00_body_gridData.UpHandler(event,this,15,0)" style="width: 159px;" class="HeadingCell" align="center"> <div style="text-align: center; overflow: hidden; width: 159px;"> <table width="100%" border="0" cellpadding="0" cellspacing="0"> <tbody> <tr> <td style="white-space: nowrap; text-align: center;" class="HeadingCellText" align="center"> Capital/Expense<br>Group</td> </tr> </tbody> </table> </div> </td> <td onclick="ctl00_body_gridData.ClickHandler(event,this,19,0)" ondblclick="ctl00_body_gridData.DblClickHandler(event,null,19,0)" onmousemove="ctl00_body_gridData.MoveHandler(event,this,5,0)" onmouseover="ctl00_body_gridData.OverHandler(event,this,0)" onmouseout="ctl00_body_gridData.OutHandler(event,this,0)" onmousedown="ctl00_body_gridData.DownHandler(event,this,19,0)" onmouseup="ctl00_body_gridData.UpHandler(event,this,19,0)" style="width: 99px;" class="HeadingCell" align="center"> <div style="text-align: center; overflow: hidden; width: 99px;"> <table width="100%" border="0" cellpadding="0" cellspacing="0"> <tbody> <tr> <td style="white-space: nowrap; text-align: center;" class="HeadingCellText" align="center">Cost Type</td> </tr> </tbody> </table> </div> </td> <td onclick="ctl00_body_gridData.ClickHandler(event,this,20,0)" ondblclick="ctl00_body_gridData.DblClickHandler(event,null,20,0)" onmousemove="ctl00_body_gridData.MoveHandler(event,this,6,0)" onmouseover="ctl00_body_gridData.OverHandler(event,this,0)" onmouseout="ctl00_body_gridData.OutHandler(event,this,0)" onmousedown="ctl00_body_gridData.DownHandler(event,this,20,0)" onmouseup="ctl00_body_gridData.UpHandler(event,this,20,0)" style="width: 81px;" class="HeadingCell" align="center"> <div style="text-align: center; overflow: hidden; width: 81px;"> <table width="100%" border="0" cellpadding="0" cellspacing="0"> <tbody> <tr> <td style="white-space: nowrap; text-align: center;" class="HeadingCellText" align="center"> Commit<br>Dollars</td> </tr> </tbody> </table> </div> </td> <td onclick="ctl00_body_gridData.ClickHandler(event,this,21,0)" ondblclick="ctl00_body_gridData.DblClickHandler(event,null,21,0)" onmousemove="ctl00_body_gridData.MoveHandler(event,this,7,0)" onmouseover="ctl00_body_gridData.OverHandler(event,this,0)" onmouseout="ctl00_body_gridData.OutHandler(event,this,0)" onmousedown="ctl00_body_gridData.DownHandler(event,this,21,0)" onmouseup="ctl00_body_gridData.UpHandler(event,this,21,0)" style="width: 81px;" class="HeadingCell" align="center"> <div style="text-align: center; overflow: hidden; width: 81px;"> <table width="100%" border="0" cellpadding="0" cellspacing="0"> <tbody> <tr> <td style="white-space: nowrap; text-align: center;" class="HeadingCellText" align="center"> Commit<br>Hours</td> </tr> </tbody> </table> </div> </td> <td onclick="ctl00_body_gridData.ClickHandler(event,this,22,0)" ondblclick="ctl00_body_gridData.DblClickHandler(event,null,22,0)" onmousemove="ctl00_body_gridData.MoveHandler(event,this,8,0)" onmouseover="ctl00_body_gridData.OverHandler(event,this,0)" onmouseout="ctl00_body_gridData.OutHandler(event,this,0)" onmousedown="ctl00_body_gridData.DownHandler(event,this,22,0)" onmouseup="ctl00_body_gridData.UpHandler(event,this,22,0)" style="width: 86px;" class="HeadingCell" align="center"> <div style="text-align: center; overflow: hidden; width: 86px;"> <table width="100%" border="0" cellpadding="0" cellspacing="0"> <tbody> <tr> <td style="white-space: nowrap; text-align: center;" class="HeadingCellText" align="center"> Commit<br>Quantity</td> </tr> </tbody> </table> </div> </td> <td onclick="ctl00_body_gridData.ClickHandler(event,this,23,0)" ondblclick="ctl00_body_gridData.DblClickHandler(event,null,23,0)" onmousemove="ctl00_body_gridData.MoveHandler(event,this,9,0)" onmouseover="ctl00_body_gridData.OverHandler(event,this,0)" onmouseout="ctl00_body_gridData.OutHandler(event,this,0)" onmousedown="ctl00_body_gridData.DownHandler(event,this,23,0)" onmouseup="ctl00_body_gridData.UpHandler(event,this,23,0)" style="width: 76px;" class="HeadingCell" align="center"> <div style="text-align: center; overflow: hidden; width: 76px;"> <table width="100%" border="0" cellpadding="0" cellspacing="0"> <tbody> <tr> <td style="white-space: nowrap; text-align: center;" class="HeadingCellText" align="center"> Control<br>Budget</td> </tr> </tbody> </table> </div> </td> <td onclick="ctl00_body_gridData.ClickHandler(event,this,24,0)" ondblclick="ctl00_body_gridData.DblClickHandler(event,null,24,0)" onmousemove="ctl00_body_gridData.MoveHandler(event,this,10,0)" onmouseover="ctl00_body_gridData.OverHandler(event,this,0)" onmouseout="ctl00_body_gridData.OutHandler(event,this,0)" onmousedown="ctl00_body_gridData.DownHandler(event,this,24,0)" onmouseup="ctl00_body_gridData.UpHandler(event,this,24,0)" style="width: 46px;" class="HeadingCell" align="center"> <div style="text-align: center; overflow: hidden; width: 46px;"> <table width="100%" border="0" cellpadding="0" cellspacing="0"> <tbody> <tr> <td style="white-space: nowrap; text-align: center;" class="HeadingCellText" align="center">FTC</td> </tr> </tbody> </table> </div> </td> <td onclick="ctl00_body_gridData.ClickHandler(event,this,25,0)" ondblclick="ctl00_body_gridData.DblClickHandler(event,null,25,0)" onmousemove="ctl00_body_gridData.MoveHandler(event,this,11,0)" onmouseover="ctl00_body_gridData.OverHandler(event,this,0)" onmouseout="ctl00_body_gridData.OutHandler(event,this,0)" onmousedown="ctl00_body_gridData.DownHandler(event,this,25,0)" onmouseup="ctl00_body_gridData.UpHandler(event,this,25,0)" style="width: 88px;" class="HeadingCell" align="center"> <div style="text-align: center; overflow: hidden; width: 88px;"> <table width="100%" border="0" cellpadding="0" cellspacing="0"> <tbody> <tr> <td style="white-space: nowrap; text-align: center;" class="HeadingCellText" align="center"> Total<br>Forecast</td> </tr> </tbody> </table> </div> </td> <td onclick="ctl00_body_gridData.ClickHandler(event,this,26,0)" ondblclick="ctl00_body_gridData.DblClickHandler(event,null,26,0)" onmousemove="ctl00_body_gridData.MoveHandler(event,this,12,0)" onmouseover="ctl00_body_gridData.OverHandler(event,this,0)" onmouseout="ctl00_body_gridData.OutHandler(event,this,0)" onmousedown="ctl00_body_gridData.DownHandler(event,this,26,0)" onmouseup="ctl00_body_gridData.UpHandler(event,this,26,0)" style="width: 50px;" class="HeadingCell" align="center"> <div style="text-align: center; overflow: hidden; width: 50px;"> <table width="100%" border="0" cellpadding="0" cellspacing="0"> <tbody> <tr> <td style="white-space: nowrap; text-align: center;" class="HeadingCellText" align="center"> Ctr<br>COB</td> </tr> </tbody> </table> </div> </td> <td onclick="ctl00_body_gridData.ClickHandler(event,this,27,0)" ondblclick="ctl00_body_gridData.DblClickHandler(event,null,27,0)" onmousemove="ctl00_body_gridData.MoveHandler(event,this,13,0)" onmouseover="ctl00_body_gridData.OverHandler(event,this,0)" onmouseout="ctl00_body_gridData.OutHandler(event,this,0)" onmousedown="ctl00_body_gridData.DownHandler(event,this,27,0)" onmouseup="ctl00_body_gridData.UpHandler(event,this,27,0)" style="width: 49px;" class="HeadingCell" align="center"> <div style="text-align: center; overflow: hidden; width: 49px;"> <table width="100%" border="0" cellpadding="0" cellspacing="0"> <tbody> <tr> <td style="white-space: nowrap; text-align: center;" class="HeadingCellText" align="center"> Ctr<br>CCB</td> </tr> </tbody> </table> </div> </td> <td onclick="ctl00_body_gridData.ClickHandler(event,this,28,0)" ondblclick="ctl00_body_gridData.DblClickHandler(event,null,28,0)" onmousemove="ctl00_body_gridData.MoveHandler(event,this,14,0)" onmouseover="ctl00_body_gridData.OverHandler(event,this,0)" onmouseout="ctl00_body_gridData.OutHandler(event,this,0)" onmousedown="ctl00_body_gridData.DownHandler(event,this,28,0)" onmouseup="ctl00_body_gridData.UpHandler(event,this,28,0)" style="width: 81px;" class="HeadingCell" align="center"> <div style="text-align: center; overflow: hidden; width: 81px;"> <table width="100%" border="0" cellpadding="0" cellspacing="0"> <tbody> <tr> <td style="white-space: nowrap; text-align: center;" class="HeadingCellText" align="center"> Ctr<br> Commit<br>$</td> </tr> </tbody> </table> </div> </td> <td onclick="ctl00_body_gridData.ClickHandler(event,this,29,0)" ondblclick="ctl00_body_gridData.DblClickHandler(event,null,29,0)" onmousemove="ctl00_body_gridData.MoveHandler(event,this,15,0)" onmouseover="ctl00_body_gridData.OverHandler(event,this,0)" onmouseout="ctl00_body_gridData.OutHandler(event,this,0)" onmousedown="ctl00_body_gridData.DownHandler(event,this,29,0)" onmouseup="ctl00_body_gridData.UpHandler(event,this,29,0)" style="width: 81px;" class="HeadingCell" align="center"> <div style="text-align: center; overflow: hidden; width: 81px;"> <table width="100%" border="0" cellpadding="0" cellspacing="0"> <tbody> <tr> <td style="white-space: nowrap; text-align: center;" class="HeadingCellText" align="center"> Ctr<br> Commit<br>Hours</td> </tr> </tbody> </table> </div> </td> <td onclick="ctl00_body_gridData.ClickHandler(event,this,30,0)" ondblclick="ctl00_body_gridData.DblClickHandler(event,null,30,0)" onmousemove="ctl00_body_gridData.MoveHandler(event,this,16,0)" onmouseover="ctl00_body_gridData.OverHandler(event,this,0)" onmouseout="ctl00_body_gridData.OutHandler(event,this,0)" onmousedown="ctl00_body_gridData.DownHandler(event,this,30,0)" onmouseup="ctl00_body_gridData.UpHandler(event,this,30,0)" style="width: 86px;" class="HeadingCell" align="center"> <div style="text-align: center; overflow: hidden; width: 86px;"> <table width="100%" border="0" cellpadding="0" cellspacing="0"> <tbody> <tr> <td style="white-space: nowrap; text-align: center;" class="HeadingCellText" align="center"> Ctr<br> Commit<br>Quantity</td> </tr> </tbody> </table> </div> </td> <td onclick="ctl00_body_gridData.ClickHandler(event,this,31,0)" ondblclick="ctl00_body_gridData.DblClickHandler(event,null,31,0)" onmousemove="ctl00_body_gridData.MoveHandler(event,this,17,0)" onmouseover="ctl00_body_gridData.OverHandler(event,this,0)" onmouseout="ctl00_body_gridData.OutHandler(event,this,0)" onmousedown="ctl00_body_gridData.DownHandler(event,this,31,0)" onmouseup="ctl00_body_gridData.UpHandler(event,this,31,0)" style="width: 95px;" class="HeadingCell" align="center"> <div style="text-align: center; overflow: hidden; width: 95px;"> <table width="100%" border="0" cellpadding="0" cellspacing="0"> <tbody> <tr> <td style="white-space: nowrap; text-align: center;" class="HeadingCellText" align="center"> Ctr<br>% Compl.</td> </tr> </tbody> </table> </div> </td> <td onclick="ctl00_body_gridData.ClickHandler(event,this,32,0)" ondblclick="ctl00_body_gridData.DblClickHandler(event,null,32,0)" onmousemove="ctl00_body_gridData.MoveHandler(event,this,18,0)" onmouseover="ctl00_body_gridData.OverHandler(event,this,0)" onmouseout="ctl00_body_gridData.OutHandler(event,this,0)" onmousedown="ctl00_body_gridData.DownHandler(event,this,32,0)" onmouseup="ctl00_body_gridData.UpHandler(event,this,32,0)" style="width: 105px;" class="HeadingCell" align="center"> <div style="text-align: center; overflow: hidden; width: 105px;"> <table width="100%" border="0" cellpadding="0" cellspacing="0"> <tbody> <tr> <td style="white-space: nowrap; text-align: center;" class="HeadingCellText" align="center"> Contractor<br>CFTC</td> </tr> </tbody> </table> </div> </td> </tr> <tr> <td id="ctl00_body_gridData_expcolgrp_0" width="16" align="center"></td> <td class="GroupHeading" colspan="20"> FCR<br>Group: Engineering</td> </tr> <tr> <td id="ctl00_body_gridData_expcolgrp_1" width="16" align="center"></td> <td class="GroupHeading" colspan="20"> FCR<br>Group: Pipe</td> </tr> <tr> <td id="ctl00_body_gridData_expcolgrp_2" width="16" align="center"></td> <td class="GroupHeading" colspan="20"> FCR<br>Group: Concrete</td> </tr> <tr> <td id="ctl00_body_gridData_expcolgrp_3" width="16" align="center"></td> <td class="GroupHeading" colspan="20"> FCR<br>Group: Insulation</td> </tr> <tr> <td id="ctl00_body_gridData_expcolgrp_4" width="16" align="center"></td> <td class="GroupHeading" colspan="20"> FCR<br>Group: Buildings</td> </tr> </tbody> </table> </td> </tr> </tbody> </table> </body> </html>

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  • Design by Contract with Microsoft .Net Code Contract

    - by Fredrik N
    I have done some talks on different events and summits about Defensive Programming and Design by Contract, last time was at Cornerstone’s Developer Summit 2010. Next time will be at SweNug (Sweden .Net User Group). I decided to write a blog post about of some stuffs I was talking about. Users are a terrible thing! Protect your self from them ”Human users have a gift for doing the worst possible thing at the worst possible time.” – Michael T. Nygard, Release It! The kind of users Michael T. Nygard are talking about is the users of a system. We also have users that uses our code, the users I’m going to focus on is the users of our code. Me and you and another developers. “Any fool can write code that a computer can understand. Good programmers write code that humans can understand.” – Martin Fowler Good programmers also writes code that humans know how to use, good programmers also make sure software behave in a predictable manner despise inputs or user actions. Design by Contract   Design by Contract (DbC) is a way for us to make a contract between us (the code writer) and the users of our code. It’s about “If you give me this, I promise to give you this”. It’s not about business validations, that is something completely different that should be part of the domain model. DbC is to make sure the users of our code uses it in a correct way, and that we can rely on the contract and write code in a way where we know that the users will follow the contract. It will make it much easier for us to write code with a contract specified. Something like the following code is something we may see often: public void DoSomething(Object value) { value.DoIKnowThatICanDoThis(); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Where “value” can be uses directly or passed to other methods and later be used. What some of us can easily forget here is that the “value” can be “null”. We will probably not passing a null value, but someone else that uses our code maybe will do it. I think most of you (including me) have passed “null” into a method because you don’t know if the argument need to be specified to a valid value etc. I bet most of you also have got the “Null reference exception”. Sometimes this “Null reference exception” can be hard and take time to fix, because we need to search among our code to see where the “null” value was passed in etc. Wouldn’t it be much better if we can as early as possible specify that the value can’t not be null, so the users of our code also know it when the users starts to use our code, and before run time execution of the code? This is where DbC comes into the picture. We can use DbC to specify what we need, and by doing so we can rely on the contract when we write our code. So the code above can actually use the DoIKnowThatICanDoThis() method on the value object without being worried that the “value” can be null. The contract between the users of the code and us writing the code, says that the “value” can’t be null.   Pre- and Postconditions   When working with DbC we are specifying pre- and postconditions.  Precondition is a condition that should be met before a query or command is executed. An example of a precondition is: “The Value argument of the method can’t be null”, and we make sure the “value” isn’t null before the method is called. Postcondition is a condition that should be met when a command or query is completed, a postcondition will make sure the result is correct. An example of a postconditon is “The method will return a list with at least 1 item”. Commands an Quires When using DbC, we need to know what a Command and a Query is, because some principles that can be good to follow are based on commands and queries. A Command is something that will not return anything, like the SQL’s CREATE, UPDATE and DELETE. There are two kinds of Commands when using DbC, the Creation commands (for example a Constructor), and Others. Others can for example be a Command to add a value to a list, remove or update a value etc. //Creation commands public Stack(int size) //Other commands public void Push(object value); public void Remove(); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   A Query, is something that will return something, for example an Attribute, Property or a Function, like the SQL’s SELECT.   There are two kinds of Queries, the Basic Queries  (Quires that aren’t based on another queries), and the Derived Queries, queries that is based on another queries. Here is an example of queries of a Stack: //Basic Queries public int Count; public object this[int index] { get; } //Derived Queries //Is related to Count Query public bool IsEmpty() { return Count == 0; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } To understand about some principles that are good to follow when using DbC, we need to know about the Commands and different Queries. The 6 Principles When working with DbC, it’s advisable to follow some principles to make it easier to define and use contracts. The following DbC principles are: Separate commands and queries. Separate basic queries from derived queries. For each derived query, write a postcondition that specifies what result will be returned, in terms of one or more basic queries. For each command, write a postcondition that specifies the value of every basic query. For every query and command, decide on a suitable precondition. Write invariants to define unchanging properties of objects. Before I will write about each of them I want you to now that I’m going to use .Net 4.0 Code Contract. I will in the rest of the post uses a simple Stack (Yes I know, .Net already have a Stack class) to give you the basic understanding about using DbC. A Stack is a data structure where the first item in, will be the first item out. Here is a basic implementation of a Stack where not contract is specified yet: public class Stack { private object[] _array; //Basic Queries public uint Count; public object this[uint index] { get { return _array[index]; } set { _array[index] = value; } } //Derived Queries //Is related to Count Query public bool IsEmpty() { return Count == 0; } //Is related to Count and this[] Query public object Top() { return this[Count]; } //Creation commands public Stack(uint size) { Count = 0; _array = new object[size]; } //Other commands public void Push(object value) { this[++Count] = value; } public void Remove() { this[Count] = null; Count--; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   Note: The Stack is implemented in a way to demonstrate the use of Code Contract in a simple way, the implementation may not look like how you would implement it, so don’t think this is the perfect Stack implementation, only used for demonstration.   Before I will go deeper into the principles I will simply mention how we can use the .Net Code Contract. I mention before about pre- and postcondition, is about “Require” something and to “Ensure” something. When using Code Contract, we will use a static class called “Contract” and is located in he “System.Diagnostics.Contracts” namespace. The contract must be specified at the top or our member statement block. To specify a precondition with Code Contract we uses the Contract.Requires method, and to specify a postcondition, we uses the Contract.Ensure method. Here is an example where both a pre- and postcondition are used: public object Top() { Contract.Requires(Count > 0, "Stack is empty"); Contract.Ensures(Contract.Result<object>() == this[Count]); return this[Count]; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   The contract above requires that the Count is greater than 0, if not we can’t get the item at the Top of a Stack. We also Ensures that the results (By using the Contract.Result method, we can specify a postcondition that will check if the value returned from a method is correct) of the Top query is equal to this[Count].   1. Separate Commands and Queries   When working with DbC, it’s important to separate Command and Quires. A method should either be a command that performs an Action, or returning information to the caller, not both. By asking a question the answer shouldn’t be changed. The following is an example of a Command and a Query of a Stack: public void Push(object value) public object Top() .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   The Push is a command and will not return anything, just add a value to the Stack, the Top is a query to get the item at the top of the stack.   2. Separate basic queries from derived queries There are two different kinds of queries,  the basic queries that doesn’t rely on another queries, and derived queries that uses a basic query. The “Separate basic queries from derived queries” principle is about about that derived queries can be specified in terms of basic queries. So this principles is more about recognizing that a query is a derived query or a basic query. It will then make is much easier to follow the other principles. The following code shows a basic query and a derived query: //Basic Queries public uint Count; //Derived Queries //Is related to Count Query public bool IsEmpty() { return Count == 0; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   We can see that IsEmpty will use the Count query, and that makes the IsEmpty a Derived query.   3. For each derived query, write a postcondition that specifies what result will be returned, in terms of one or more basic queries.   When the derived query is recognize we can follow the 3ed principle. For each derived query, we can create a postcondition that specifies what result our derived query will return in terms of one or more basic queries. Remember that DbC is about contracts between the users of the code and us writing the code. So we can’t use demand that the users will pass in a valid value, we must also ensure that we will give the users what the users wants, when the user is following our contract. The IsEmpty query of the Stack will use a Count query and that will make the IsEmpty a Derived query, so we should now write a postcondition that specified what results will be returned, in terms of using a basic query and in this case the Count query, //Basic Queries public uint Count; //Derived Queries public bool IsEmpty() { Contract.Ensures(Contract.Result<bool>() == (Count == 0)); return Count == 0; } The Contract.Ensures is used to create a postcondition. The above code will make sure that the results of the IsEmpty (by using the Contract.Result to get the result of the IsEmpty method) is correct, that will say that the IsEmpty will be either true or false based on Count is equal to 0 or not. The postcondition are using a basic query, so the IsEmpty is now following the 3ed principle. We also have another Derived Query, the Top query, it will also need a postcondition and it uses all basic queries. The Result of the Top method must be the same value as the this[] query returns. //Basic Queries public uint Count; public object this[uint index] { get { return _array[index]; } set { _array[index] = value; } } //Derived Queries //Is related to Count and this[] Query public object Top() { Contract.Ensures(Contract.Result<object>() == this[Count]); return this[Count]; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   4. For each command, write a postcondition that specifies the value of every basic query.   For each command we will create a postconditon that specifies the value of basic queries. If we look at the Stack implementation we will have three Commands, one Creation command, the Constructor, and two others commands, Push and Remove. Those commands need a postcondition and they should include basic query to follow the 4th principle. //Creation commands public Stack(uint size) { Contract.Ensures(Count == 0); Count = 0; _array = new object[size]; } //Other commands public void Push(object value) { Contract.Ensures(Count == Contract.OldValue<uint>(Count) + 1); Contract.Ensures(this[Count] == value); this[++Count] = value; } public void Remove() { Contract.Ensures(Count == Contract.OldValue<uint>(Count) - 1); this[Count] = null; Count--; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   As you can see the Create command will Ensures that Count will be 0 when the Stack is created, when a Stack is created there shouldn’t be any items in the stack. The Push command will take a value and put it into the Stack, when an item is pushed into the Stack, the Count need to be increased to know the number of items added to the Stack, and we must also make sure the item is really added to the Stack. The postconditon of the Push method will make sure the that old value of the Count (by using the Contract.OldValue we can get the value a Query has before the method is called)  plus 1 will be equal to the Count query, this is the way we can ensure that the Push will increase the Count with one. We also make sure the this[] query will now contain the item we pushed into the Stack. The Remove method must make sure the Count is decreased by one when the top item is removed from the Stack. The Commands is now following the 4th principle, where each command now have a postcondition that used the value of basic queries. Note: The principle says every basic Query, the Remove only used one Query the Count, it’s because this command can’t use the this[] query because an item is removed, so the only way to make sure an item is removed is to just use the Count query, so the Remove will still follow the principle.   5. For every query and command, decide on a suitable precondition.   We have now focused only on postcondition, now time for some preconditons. The 5th principle is about deciding a suitable preconditon for every query and command. If we starts to look at one of our basic queries (will not go through all Queries and commands here, just some of them) the this[] query, we can’t pass an index that is lower then 1 (.Net arrays and list are zero based, but not the stack in this blog post ;)) and the index can’t be lesser than the number of items in the stack. So here we will need a preconditon. public object this[uint index] { get { Contract.Requires(index >= 1); Contract.Requires(index <= Count); return _array[index]; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Think about the Contract as an documentation about how to use the code in a correct way, so if the contract could be specified elsewhere (not part of the method body), we could simply write “return _array[index]” and there is no need to check if index is greater or lesser than Count, because that is specified in a “contract”. The implementation of Code Contract, requires that the contract is specified in the code. As a developer I would rather have this contract elsewhere (Like Spec#) or implemented in a way Eiffel uses it as part of the language. Now when we have looked at one Query, we can also look at one command, the Remove command (You can see the whole implementation of the Stack at the end of this blog post, where precondition is added to more queries and commands then what I’m going to show in this section). We can only Remove an item if the Count is greater than 0. So we can write a precondition that will require that Count must be greater than 0. public void Remove() { Contract.Requires(Count > 0); Contract.Ensures(Count == Contract.OldValue<uint>(Count) - 1); this[Count] = null; Count--; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   6. Write invariants to define unchanging properties of objects.   The last principle is about making sure the object are feeling great! This is done by using invariants. When using Code Contract we can specify invariants by adding a method with the attribute ContractInvariantMethod, the method must be private or public and can only contains calls to Contract.Invariant. To make sure the Stack feels great, the Stack must have 0 or more items, the Count can’t never be a negative value to make sure each command and queries can be used of the Stack. Here is our invariant for the Stack object: [ContractInvariantMethod] private void ObjectInvariant() { Contract.Invariant(Count >= 0); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   Note: The ObjectInvariant method will be called every time after a Query or Commands is called. Here is the full example using Code Contract:   public class Stack { private object[] _array; //Basic Queries public uint Count; public object this[uint index] { get { Contract.Requires(index >= 1); Contract.Requires(index <= Count); return _array[index]; } set { Contract.Requires(index >= 1); Contract.Requires(index <= Count); _array[index] = value; } } //Derived Queries //Is related to Count Query public bool IsEmpty() { Contract.Ensures(Contract.Result<bool>() == (Count == 0)); return Count == 0; } //Is related to Count and this[] Query public object Top() { Contract.Requires(Count > 0, "Stack is empty"); Contract.Ensures(Contract.Result<object>() == this[Count]); return this[Count]; } //Creation commands public Stack(uint size) { Contract.Requires(size > 0); Contract.Ensures(Count == 0); Count = 0; _array = new object[size]; } //Other commands public void Push(object value) { Contract.Requires(value != null); Contract.Ensures(Count == Contract.OldValue<uint>(Count) + 1); Contract.Ensures(this[Count] == value); this[++Count] = value; } public void Remove() { Contract.Requires(Count > 0); Contract.Ensures(Count == Contract.OldValue<uint>(Count) - 1); this[Count] = null; Count--; } [ContractInvariantMethod] private void ObjectInvariant() { Contract.Invariant(Count >= 0); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Summary By using Design By Contract we can make sure the users are using our code in a correct way, and we must also make sure the users will get the expected results when they uses our code. This can be done by specifying contracts. To make it easy to use Design By Contract, some principles may be good to follow like the separation of commands an queries. With .Net 4.0 we can use the Code Contract feature to specify contracts.

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  • Gparted resize of an extended partition fails with error "can't have overlapping partitions".

    - by Marcus
    I just decided to install Ubuntu 12.04 alongside Windows 7 on my Dell laptop. However I didn't do this manually but instead used the "Install Ubuntu alongside Windows 7" option during the installation. Now the partition that Ubuntu runs in has very little space and I am getting warning messages. I'm trying to use gparted 0.12.1-5 (via a live CD) to give Windows less space and give Ubuntu more. I've managed to remove 100GB from the Windows partition so I now have some unallocated space between Windows and Ubuntu. This is what it looks like inside Ubuntu (not using the live CD, since it won't let me mount a USB to save a screenshot): So first I take sda4 (extended?) and resize it to the left so it takes up all the unallocated space. Then I resize sda5 (ext4) as well so it takes up all the new space. However, when I hit apply, it fails on the first action (resizing sd4) with the error message can't have overlapping partitions. Any ideas as to why this happens? I also tried resizing sda4 by just a few MB so that it definitely didn't overlap anything, but I still got the same error message. To clarify, I am using gparted from the LiveCD, I just took the screenshot from Ubuntu. I couldn't attach the details file containing the error information from gparted because I can't mount a USB drive when I'm running from the LiveCD. I'm tried following the guide on the gparted website but it says Invalid argument or something like that. If the gparted details are needed, I may need some hints on how to solve the USB issue as well. :)

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  • SQL SERVER – SSMS: Disk Usage Report

    - by Pinal Dave
    Let us start with humor!  I think we the series on various reports, we come to a logical point. We covered all the reports at server level. This means the reports we saw were targeted towards activities that are related to instance level operations. These are mostly like how a doctor diagnoses a patient. At this point I am reminded of a dialog which I read somewhere: Patient: Doc, It hurts when I touch my head. Doc: Ok, go on. What else have you experienced? Patient: It hurts even when I touch my eye, it hurts when I touch my arms, it even hurts when I touch my feet, etc. Doc: Hmmm … Patient: I feel it hurts when I touch anywhere in my body. Doc: Ahh … now I get it. You need a plaster to your finger John. Sometimes the server level gives an indicator to what is happening in the system, but we need to get to the root cause for a specific database. So, this is the first blog in series where we would start discussing about database level reports. To launch database level reports, expand selected server in Object Explorer, expand the Databases folder, and then right-click any database for which we want to look at reports. From the menu, select Reports, then Standard Reports, and then any of database level reports. In this blog, we would talk about four “disk” reports because they are similar: Disk Usage Disk Usage by Top Tables Disk Usage by Table Disk Usage by Partition Disk Usage This report shows multiple information about the database. Let us discuss them one by one.  We have divided the output into 5 different sections. Section 1 shows the high level summary of the database. It shows the space used by database files (mdf and ldf). Under the hood, the report uses, various DMVs and DBCC Commands, it is using sys.data_spaces and DBCC SHOWFILESTATS. Section 2 and 3 are pie charts. One for data file allocation and another for the transaction log file. Pie chart for “Data Files Space Usage (%)” shows space consumed data, indexes, allocated to the SQL Server database, and unallocated space which is allocated to the SQL Server database but not yet filled with anything. “Transaction Log Space Usage (%)” used DBCC SQLPERF (LOGSPACE) and shows how much empty space we have in the physical transaction log file. Section 4 shows the data from Default Trace and looks at Event IDs 92, 93, 94, 95 which are for “Data File Auto Grow”, “Log File Auto Grow”, “Data File Auto Shrink” and “Log File Auto Shrink” respectively. Here is an expanded view for that section. If default trace is not enabled, then this section would be replaced by the message “Trace Log is disabled” as highlighted below. Section 5 of the report uses DBCC SHOWFILESTATS to get information. Here is the enhanced version of that section. This shows the physical layout of the file. In case you have In-Memory Objects in the database (from SQL Server 2014), then report would show information about those as well. Here is the screenshot taken for a different database, which has In-Memory table. I have highlighted new things which are only shown for in-memory database. The new sections which are highlighted above are using sys.dm_db_xtp_checkpoint_files, sys.database_files and sys.data_spaces. The new type for in-memory OLTP is ‘FX’ in sys.data_space. The next set of reports is targeted to get information about a table and its storage. These reports can answer questions like: Which is the biggest table in the database? How many rows we have in table? Is there any table which has a lot of reserved space but its unused? Which partition of the table is having more data? Disk Usage by Top Tables This report provides detailed data on the utilization of disk space by top 1000 tables within the Database. The report does not provide data for memory optimized tables. Disk Usage by Table This report is same as earlier report with few difference. First Report shows only 1000 rows First Report does order by values in DMV sys.dm_db_partition_stats whereas second one does it based on name of the table. Both of the reports have interactive sort facility. We can click on any column header and change the sorting order of data. Disk Usage by Partition This report shows the distribution of the data in table based on partition in the table. This is so similar to previous output with the partition details now. Here is the query taken from profiler. SELECT row_number() OVER (ORDER BY a1.used_page_count DESC, a1.index_id) AS row_number ,      (dense_rank() OVER (ORDER BY a5.name, a2.name))%2 AS l1 ,      a1.OBJECT_ID ,      a5.name AS [schema] ,       a2.name ,       a1.index_id ,       a3.name AS index_name ,       a3.type_desc ,       a1.partition_number ,       a1.used_page_count * 8 AS total_used_pages ,       a1.reserved_page_count * 8 AS total_reserved_pages ,       a1.row_count FROM sys.dm_db_partition_stats a1 INNER JOIN sys.all_objects a2  ON ( a1.OBJECT_ID = a2.OBJECT_ID) AND a1.OBJECT_ID NOT IN (SELECT OBJECT_ID FROM sys.tables WHERE is_memory_optimized = 1) INNER JOIN sys.schemas a5 ON (a5.schema_id = a2.schema_id) LEFT OUTER JOIN  sys.indexes a3  ON ( (a1.OBJECT_ID = a3.OBJECT_ID) AND (a1.index_id = a3.index_id) ) WHERE (SELECT MAX(DISTINCT partition_number) FROM sys.dm_db_partition_stats a4 WHERE (a4.OBJECT_ID = a1.OBJECT_ID)) >= 1 AND a2.TYPE <> N'S' AND  a2.TYPE <> N'IT' ORDER BY a5.name ASC, a2.name ASC, a1.index_id, a1.used_page_count DESC, a1.partition_number Using all of the above reports, you should be able to get the usage of database files and also space used by tables. I think this is too much disk information for a single blog and I hope you have used them in the past to get data. Do let me know if you found anything interesting using these reports in your environments. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Server Management Studio, SQL Tips and Tricks, T SQL Tagged: SQL Reports

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  • winusb formatting and installation error, lost data storage on 32gb flash drive

    - by Cary Felton
    i recently purchased a pny brand 32gb usb drive to use for configuring a dual boot on my computer, and for hdd files backup. i also recently installed zorin os 6.1 as my main os, and then downloaded winusb for linux, and set it to install the iso for windows 8 release preview as the activation code is still good untill jan.2013, and there was an error on the installation. i rebooted the computer, plugged in the usb drive, and i went from 32gb usable space to somehow having a partitioned drive (mounted as two separate drives) one being 3.7gb, and the other being i believe 25gb or so... i then formatted the drive with gparted back to fat32, and it still read as a windows usb with the installation files on it still? so then i took my usb drive to my library which runs windows 8, i installed bootice, and completely reformatted my usb drive, and somehow it is usable, but still not perfect. it reads i only have 29.9gb usable space... i have already thought of the non usable area, and that doesnt account for this error as when i first bought the drive and plugged it in on linux, it read total drive space was 32.2 and exactly 32 was usable. somehow i am short by 2gb of space which is very critical for what i am doing. i love linux, i only needed windows for bluray playback with daplayer as it wont work well in wine, but if i keep losing space on my usb drives im afraid ill have to switch back. any help would be appreciated as i already visited pny's site, and they have no support for this issue, and im not that fond of partitions, file systems, or formatting.

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  • Identify memory leak in Java app

    - by Vincent Ma
    One important advantage of java is programer don't care memory management and GC handle it well. Maybe this is one reason why java is more popular. As Java programer you real dont care it? After you meet Out of memory you will realize it it’s not true. Java GC and memory is big topic you can get some information in here Today just let me show how to identify memory leak quickly. Let quickly review demo java code, it’s one kind of memory leak in our code, using static collection and always add some object. import java.util.ArrayList;import java.util.List; public class MemoryTest { public static void main(String[] args) { new Thread(new MemoryLeak(), "MemoryLeak").start(); }} class MemoryLeak implements Runnable { public static List<Integer> leakList = new ArrayList<Integer>(); public void run() { int num =0; while(true) { try { Thread.sleep(1); } catch (InterruptedException e) { } num++; Integer i = new Integer(num); leakList.add(i); } }} run it with java -verbose:gc -XX:+PrintGCDetails -Xmx60m -XX:MaxPermSize=160m MemoryTest after about some minuts you will get Exception in thread "MemoryLeak" java.lang.OutOfMemoryError: Java heap space at java.util.Arrays.copyOf(Arrays.java:2760) at java.util.Arrays.copyOf(Arrays.java:2734) at java.util.ArrayList.ensureCapacity(ArrayList.java:167) at java.util.ArrayList.add(ArrayList.java:351) at MemoryLeak.run(MemoryTest.java:25) at java.lang.Thread.run(Thread.java:619)Heap def new generation total 18432K, used 3703K [0x045e0000, 0x059e0000, 0x059e0000) eden space 16384K, 22% used [0x045e0000, 0x0497dde0, 0x055e0000) from space 2048K, 0% used [0x055e0000, 0x055e0000, 0x057e0000) to space 2048K, 0% used [0x057e0000, 0x057e0000, 0x059e0000) tenured generation total 40960K, used 40959K [0x059e0000, 0x081e0000, 0x081e0000) the space 40960K, 99% used [0x059e0000, 0x081dfff8, 0x081e0000, 0x081e0000) compacting perm gen total 12288K, used 2083K [0x081e0000, 0x08de0000, 0x10de0000) the space 12288K, 16% used [0x081e0000, 0x083e8c50, 0x083e8e00, 0x08de0000)No shared spaces configured. OK let us quickly identify it using JProfile Download JProfile in here  Run JProfile and attach MemoryTest get largest size of  Objects in Memory View in here is Integer then select Integer and go to Heap Walker. get GC Graph for this object  Then you get detail code raise this issue quickly now.  That is enjoy it.

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  • installing ubuntu on SSD

    - by kunal
    Going to install Ubuntu 10.10 on new intel x25M 80GB SSD. It will be fresh install. I have been googling for past few days and getting overwhelming articles/blogs/Q&As. One particularly very useful being: Optimize for SSD (I could not post other links as i dont have enough credits) But with so many suggestions and differences of opinions (on different links) this simple OS install process seems to be daunting task to me and I really want to stick with ubuntu (although have used for very short period of time). Can someone help me by answering few questions (yes they are repeated as i couldnt comprehend the answers elsewhere) which file system (ext2/3/4 or something else)? (consider SSD life) can it be changed after installation? should i partition the disk? (as we do in traditional HDD) for now, no plan of dual booting. Only ubuntu will live on scarce space of 80GB SSD. i have 2 GB RAM, should i still allocate swap space (if i dont allocate swap space, can i still hibernate the machine)? will swap space impact SSD life? should i consider putting additional 1GB RAM to avoid swap space? Linux experience - absolute novice intended usage - heavy browsing, programming, regular video/music and some other non-CPU/RAM-intensive programs. will backup big files to an external hard drive. laptop config - 3 yr old vaio, core2 duo, 2GB RAM Please pardon the repetition and i really appreciate anyone helping me getting started with ubuntu.

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  • A rather long question about installation/uninstall

    - by user2364312
    Ok so here's the deal guys, last week I decided I want to install Ubunutu again because I really missed it. (Last time I had an ubunutu was 7.somehting) I downloaded 12.04 and isntalled it via bootable usb device. Knowing how dual boots works I cleared up some space on my hard disc before hand using the windows 7 built in disc manager. During Ubunutu's installation I thought that by choosing "Install Ubuntu alongside Windows 7" will automatically just use the space I cleared before, but apperentaly it did not since that partition is still 100% free space. On what partition is Ubunutu installed when using that method? And how can I uninstall it to re-install it back on the space I cleared up for it? Thank you very your time reading and helping!

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  • 5 Best Practices - Laying the Foundation for WebCenter Projects

    - by Kellsey Ruppel
    Today’s guest post comes from Oracle WebCenter expert John Brunswick. John specializes in enterprise portal and content management solutions and actively contributes to the enterprise software business community and has authored a series of articles about optimal business involvement in portal, business process management and SOA development, examining ways of helping organizations move away from monolithic application development. We’re happy to have John join us today! Maximizing success with Oracle WebCenter portal requires a strategic understanding of Oracle WebCenter capabilities.  The following best practices enable the creation of portal solutions with minimal resource overhead, while offering the greatest flexibility for progressive elaboration. They are inherently project agnostic, enabling a strong foundation for future growth and an expedient return on your investment in the platform.  If you are able to embrace even only a few of these practices, you will materially improve your deployment capability with WebCenter. 1. Segment Duties Around 3Cs - Content, Collaboration and Contextual Data "Agility" is one of the most common business benefits touted by modern web platforms.  It sounds good - who doesn't want to be Agile, right?  How exactly IT organizations go about supplying agility to their business counterparts often lacks definition - hamstrung by ambiguity. Ultimately, businesses want to benefit from reduced development time to deliver a solution to a particular constituent, which is augmented by as much self-service as possible to develop and manage the solution directly. All done in the absence of direct IT involvement. With Oracle WebCenter's depth in the areas of content management, pallet of native collaborative services, enterprise mashup capability and delegated administration, it is very possible to execute on this business vision at a technical level. To realize the benefits of the platform depth we can think of Oracle WebCenter's segmentation of duties along the lines of the 3 Cs - Content, Collaboration and Contextual Data.  All three of which can have their foundations developed by IT, then provisioned to the business on a per role basis. Content – Oracle WebCenter benefits from an extremely mature content repository.  Work flow, audit, notification, office integration and conversion capabilities for documents (HTML & PDF) make this a haven for business users to take control of content within external and internal portals, custom applications and web sites.  When deploying WebCenter portal take time to think of areas in which IT can provide the "harness" for content to reside, then allow the business to manage any content items within the site, using the content foundation to ensure compliance with business rules and process.  This frees IT to work on more mission critical challenges and allows the business to respond in short order to emerging market needs. Collaboration – Native collaborative services and WebCenter spaces are a perfect match for business users who are looking to enable document sharing, discussions and social networking.  The ability to deploy the services is granular and on the basis of roles scoped to given areas of the system - much like the first C “content”.  This enables business analysts to design the roles required and IT to provision with peace of mind that users leveraging the collaborative services are only able to do so in explicitly designated areas of a site. Bottom line - business will not need to wait for IT, but cannot go outside of the scope that has been defined based on their roles. Contextual Data – Collaborative capabilities are most powerful when included within the context of business data.  The ability to supply business users with decision shaping data that they can include in various parts of a portal or portals, just as they would with content items, is one of the most powerful aspects of Oracle WebCenter.  Imagine a discussion about new store selection for a retail chain that re-purposes existing information from business intelligence services about various potential locations and or custom backend systems - presenting it directly in the context of the discussion.  If there are some data sources that are preexisting in your enterprise take a look at how they can be made into discrete offerings within the portal, then scoped to given business user roles for inclusion within collaborative activities. 2. Think Generically, Execute Specifically Constructs.  Anyone who has spent much time around me knows that I am obsessed with this word.  Why? Because Constructs offer immense power - more than APIs, Web Services or other technical capability. Constructs offer organizations the ability to leverage a platform's native characteristics to offer substantial business functionality - without writing code.  This concept becomes more powerful with the additional understanding of the concepts from the platform that an organization learns over time.  Let's take a look at an example of where an Oracle WebCenter construct can substantially reduce the time to get a subscription-based site out the door and into the hands of the end consumer. Imagine a site that allows members to subscribe to specific disciplines to access information and application data around that various discipline.  A space is a collection of secured pages within Oracle WebCenter.  Spaces are not only secured, but also default content stored within it to be scoped automatically to that space. Taking this a step further, Oracle WebCenter’s Activity Stream surfaces events, discussions and other activities that are scoped to the given user on the basis of their space affiliations.  In order to have a portal that would allow users to "subscribe" to information around various disciplines - spaces could be used out of the box to achieve this capability and without using any APIs or low level technical work to achieve this. 3. Make Governance Work for You Imagine driving down the street without the painted lines on the road.  The rules of the road are so ingrained in our minds, we often do not think about the process, but seemingly mundane lane markers are critical enablers. Lane markers allow us to travel at speeds that would be impossible if not for the agreed upon direction of flow. Additionally and more importantly, it allows people to act autonomously - going where they please at any given time. The return on the investment for mobility is high enough for people to buy into globally agreed up governance processes. In Oracle WebCenter we can use similar enablers to lane markers.  Our goal should be to enable the flow of information and provide end users with the ability to arrive at business solutions as needed, not on the basis of cumbersome processes that cannot meet the business needs in a timely fashion. How do we do this? Just as with "Segmentation of Duties" Oracle WebCenter technologies offer the opportunity to compartmentalize various business initiatives from each other within the system due to constructs and security that are available to use within the platform. For instance, when a WebCenter space is created, any content added within that space by default will be secured to that particular space and inherits meta data that is associated with a folder created for the space. Oracle WebCenter content uses meta data to support a broad range of rich ECM functionality and can automatically impart retention, workflow and other policies automatically on the basis of what has been defaulted for that space. Depending on your business needs, this paradigm will also extend to sub sections of a space, offering some interesting possibilities to enable automated management around content. An example may be press releases within a particular area of an extranet that require a five year retention period and need to the reviewed by marketing and legal before release.  The underlying content system will transparently take care of this process on the basis of the above rules, enabling peace of mind over unstructured data - which could otherwise become overwhelming. 4. Make Your First Project Your Second Imagine if Michael Phelps was competing in a swimming championship, but told right before his race that he had to use a brand new stroke.  There is no doubt that Michael is an outstanding swimmer, but chances are that he would like to have some time to get acquainted with the new stroke. New technologies should not be treated any differently.  Before jumping into the deep end it helps to take time to get to know the new approach - even though you may have been swimming thousands of times before. To quickly get a handle on Oracle WebCenter capabilities it can be helpful to deploy a sandbox for the team to use to share project documents, discussions and announcements in an effort to help the actual deployment get under way, while increasing everyone’s knowledge of the platform and its functionality that may be helpful down the road. Oracle Technology Network has made a pre-configured virtual machine available for download that can be a great starting point for this exercise. 5. Get to Know the Community If you are reading this blog post you have most certainly faced a software decision or challenge that was solved on the basis of a small piece of missing critical information - which took substantial research to discover.  Chances were also good that somewhere, someone had already come across this information and would have been excited to share it. There is no denying the power of passionate, connected users, sharing key tips around technology.  The Oracle WebCenter brand has a rich heritage that includes industry-leading technology and practitioners.  With the new Oracle WebCenter brand, opportunities to connect with these experts has become easier. Oracle WebCenter Blog Oracle Social Enterprise LinkedIn WebCenter Group Oracle WebCenter Twitter Oracle WebCenter Facebook Oracle User Groups Additionally, there are various Oracle WebCenter related blogs by an excellent grouping of services partners.

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  • Need Help With Partioning

    - by Rakesh Kumar
    I bought a new laptop with no OS and decided to try to linux (Ubuntu) for the first time in my life. It was a clean install, my laptop had no other OS present in it, not even DOS. While installing, it asked for partitioning. Out of the 320GB of free space I created a new partition of 20 GB and installed Ubuntu in it. The rest of the 300GB is still available as free space. Soon I realized that I can't use the 300GB of space and that only 20GB is available to me for use. Can anyone tell me how I can take away some free space away from the 300GB and add that to my 20GB partition? I have installed the Gparted Partition editor from the Ubuntu Software Center but have no idea how to go ahead with it. Thanks :)

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  • GParted wont resize extended partitions

    - by Magnum Frost
    I have dual booted windows 7 and Ubuntu 12.04 LTS and have decided that I need more space on my Ubuntu partition. I used gparted on a Live CD to shrink my Windows 7 partition (/dev/sda3) but when i try to resize the extended partition (/dev/sda4), which houses my linux partition (/dev/sda6), the right click options are greyed out and there is a key next to the extended partition. I have resized the partitions within the extended partition before to provide room, but now I can go no further with that, and need to grow the extended partition. The free space lies to the left of the extended partition and there is a small amount of free space directly to the right as well. Also, within the extended partition is /dev/sda5 (ntfs) , which I have no idea what is on it, but most of the space (3.42GB) is used, /dev/sda6 (ext4, mount point: /), my partition containing Linux, and /dev/sda7 (linux-swap). I hope you guys can help me with this because I really don't want to screw something up while trying to resize the extended partition.

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  • Resizing partition using Gparted gives "can't have overlapping partitions" error

    - by Marcus
    I just decided to install Ubuntu 12.04 alongside Windows 7 on my Dell laptop. However I didn't do this manually but instead used the "Run Ubuntu alongside Windows 7" option upon installation, and now the partition that Ubuntu runs on has very little space (It's giving me warnings). I'm trying to use Gparted 0.12.1-5 (via a live CD) to give Windows less space and give Ubuntu more. I've managed to remove 100GB from the Windows partition so I now have some unallocated space between Windows and Ubuntu. This is what it looks like inside Ubuntu (not using the live CD, since it won't let me mount a USB to save a screenshot): http://i.stack.imgur.com/0keQq.png So first I take sda4 (extended?) and resize it to the left so it takes up all the unallocated space. Then I resize sda5 (ext4) as well so it takes up all the new space. However, when I hit apply, it fails on the first action (resizing sd4), saying "can't have overlapping partitions". Any ideas as to why this happens? I also tried resizing sda4 by just a few MB so that it definitely didn't overlap anything, but I still got the same error message. To clarify, I am doing it using the CD, I just took the screenshot from Ubuntu. Any help would be greatly appreciated! And again, I can't mount any USB (I'm following the guide on the gparted website but it says "Invalid argument" or something like that) so I couldn't attach the details file from Gparted. If this is needed, I may need some hints on how to solve the USB issue as well. :) Thanks

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  • Speed up lighting in deferred shading

    - by kochol
    I implemented a simple deferred shading renderer. I use 3 G-Buffer for storing position (R32F), normal (G16R16F) and albedo (ARGB8). I use sphere map algorithm to store normals in world space. Currently I use inverse of view * projection matrix to calculate the position of each pixel from stored depth value. First I want to avoid per pixel matrix multiplication for calculating the position. Is there another way to store and calculate position in G-Buffer without the need of matrix multiplication Store the normal in view space Every lighting in my engine is in world space and I want do the lighting in view space to speed up my lighting pass. I want an optimized lighting pass for my deferred engine.

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  • Upgrade issues due to broken "dependency problems prevent configuration of linux-image-generic" error

    - by tsukune1791
    okay, I've recently upgrade from 11.10 to 12.04 and I've been having some issues. I don't know if its a bug or not, but I thought I would submit it here. Okay here's a little background; I ran the distro update from the update manager and got a couple errors that I didn't catch. the computer restarted, and when I logged the Launcher and my top bar of the Ubuntu desktop didn't load. While it was trying to load a couple error messages came up, I think they were called "apport", saying they couldn't send the bug information for some reason. I believe it said somethings wrong with my internet connection, but nothing's wrong with it. Anyway I tried running some things in terminal, namely sudo apt-get -f install sudo apt-get upgrade sudo apt-get dist-upgrade and keep getting the following errors; dustin@marceau-laptop:~$ sudo apt-get dist-upgrade [sudo] password for dustin: Reading package lists... Done Building dependency tree Reading state information... Done Calculating upgrade... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. 4 not fully installed or removed. After this operation, 0 B of additional disk space will be used. Do you want to continue [Y/n]? Y Setting up initramfs-tools (0.99ubuntu13) ... update-initramfs: deferring update (trigger activated) Setting up linux-image-3.2.0-24-generic (3.2.0-24.37) ... Running depmod. update-initramfs: deferring update (hook will be called later) Examining /etc/kernel/postinst.d. run-parts: executing /etc/kernel/postinst.d/dkms 3.2.0-24-generic /boot/vmlinuz-3.2.0-24-generic run-parts: executing /etc/kernel/postinst.d/initramfs-tools 3.2.0-24-generic /boot/vmlinuz-3.2.0-24-generic update-initramfs: Generating /boot/initrd.img-3.2.0-24-generic run-parts: executing /etc/kernel/postinst.d/pm-utils 3.2.0-24-generic /boot/vmlinuz-3.2.0-24-generic run-parts: executing /etc/kernel/postinst.d/update-notifier 3.2.0-24-generic /boot/vmlinuz-3.2.0-24-generic run-parts: executing /etc/kernel/postinst.d/zz-runlilo 3.2.0-24-generic /boot/vmlinuz-3.2.0-24-generic Fatal: No images have been defined. run-parts: /etc/kernel/postinst.d/zz-runlilo exited with return code 1 Failed to process /etc/kernel/postinst.d at /var/lib/dpkg/info/linux-image-3.2.0-24-generic.postinst line 1010. dpkg: error processing linux-image-3.2.0-24-generic (--configure): subprocess installed post-installation script returned error exit status 2 dpkg: dependency problems prevent configuration of linux-image-generic: linux-image-generic depends on linux-image-3.2.0-24-generic; however: Package linux-image-3.2.0-24-generic is not configured yet. dpkg: error processing linux-image-generic (--configure): dependency problems - leaving unconfigured dpkg: dependency problems prevent configuration of linux-generic: linux-generic depends on linux-image-generic (= 3.2.0.24.26); however: Package linux-image-generic is not configured yet. dpkg: error processing linux-generic (--configure): dependency problems - leaving unconfigured Processing triggers for initramfs-tools ... No apport report written because the error message indicates its a followup error from a previous failure. No apport report written because the error message indicates its a followup error from a previous failure. update-initramfs: Generating /boot/initrd.img-3.2.0-24-generic Fatal: No images have been defined. run-parts: /etc/initramfs/post-update.d//runlilo exited with return code 1 dpkg: error processing initramfs-tools (--configure): subprocess installed post-installation script returned error exit status 1 No apport report written because MaxReports is reached already Errors were encountered while processing: linux-image-3.2.0-24-generic linux-image-generic linux-generic initramfs-tools localepurge: Disk space freed in /usr/share/locale: 0 KiB localepurge: Disk space freed in /usr/share/man: 0 KiB localepurge: Disk space freed in /usr/share/gnome/help: 0 KiB localepurge: Disk space freed in /usr/share/omf: 0 KiB localepurge: Disk space freed in /usr/share/doc/kde/HTML: 0 KiB Total disk space freed by localepurge: 0 KiB E: Sub-process /usr/bin/dpkg returned an error code (1) And my Ubuntu desktop is still not working. I can log into Gnome and Ubuntu 2D but the Launcher, I think it's call, doesn't load. Can someone help me fix these error, or point me in the right direction to get them fixed? It is much appriciated.

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  • IPv4 private address assignment

    - by helloworld922
    I'm working on a private network which uses static IPv4 addresses as well as DHCP addressing for the physical LAN network. At a previous company I worked at they would assign static addresses in the 10.*.*.* space and all DHCP/LAN addresses were assigned in the 192.168.*.* space. Both of these address spaces are defined in the IPv4 private address space and there were never any internal conflicts. From personal experience at home, school, at work, and pretty much any other machine I've dealt with extensively (Windows and a few Linux distros), the DHCP server would always by default choose an address from the 192.168.*.* address space. Now my question is can I rely on this behavior? Do DHCP servers always by default assign from the 192.168.*.* pool (or any pool other than the 10.*.*.* pool), leaving the 10.*.*.* pool free for private static addressing? If not, under what conditions might a DHCP server choose an address in the 10.*.*.* address space?

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  • Precision loss when transforming from cartesian to isometric

    - by Justin Skiles
    My goal is to display a tile map in isometric projection. This tile map has 25 tiles across and 25 tiles down. Each tile is 32x32. See below for how I'm accomplishing this. World Space World Space to Screen Space Rotation (45 degrees) Using a 2D rotation matrix, I use the following: double rotation = Math.PI / 4; double rotatedX = ((tileWorldX * Math.Cos(rotation)) - ((tileWorldY * Math.Sin(rotation))); double rotatedY = ((tileWorldX * Math.Sin(rotation)) + (tileWorldY * Math.Cos(rotation))); World Space to Screen Space Scale (Y-axis reduced by 50%) Here I simply scale down the Y value by a factor of 0.5. Problem And it works, kind of. There are some tiny 1px-2px gaps between some of the tiles when rendering. I think there's some precision loss somewhere, or I'm not understanding how to get these tiles to fit together perfectly. I'm not truncating or converting my values to non-decimal types until I absolutely have to (when I pass to the render method, which only takes integers). I'm not sure how to guarantee pixel perfect rendering precision when I'm rotating and scaling on a level of higher precision. Any advice? Do I need to supply for information?

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  • Finding furthermost point in game world

    - by user13414
    I am attempting to find the furthermost point in my game world given the player's current location and a normalized direction vector in screen space. My current algorithm is: convert player world location to screen space multiply the direction vector by a large number (2000) and add it to the player's screen location to get the distant screen location convert the distant screen location to world space create a line running from the player's world location to the distant world location loop over the bounding "walls" (of which there are always 4) of my game world check whether the wall and the line intersect if so, where they intersect is the furthermost point of my game world in the direction of the vector Here it is, more or less, in code: public Vector2 GetFurthermostWorldPoint(Vector2 directionVector) { var screenLocation = entity.WorldPointToScreen(entity.Location); var distantScreenLocation = screenLocation + (directionVector * 2000); var distantWorldLocation = entity.ScreenPointToWorld(distantScreenLocation); var line = new Line(entity.Center, distantWorldLocation); float intersectionDistance; Vector2 intersectionPoint; foreach (var boundingWall in entity.Level.BoundingWalls) { if (boundingWall.Intersects(line, out intersectionDistance, out intersectionPoint)) { return intersectionPoint; } } Debug.Assert(false, "No intersection found!"); return Vector2.Zero; } Now this works, for some definition of "works". I've found that the further out my distant screen location is, the less chance it has of working. When digging into the reasons why, I noticed that calls to Viewport.Unproject could result in wildly varying return values for points that are "far away". I wrote this stupid little "test" to try and understand what was going on: [Fact] public void wtf() { var screenPositions = new Vector2[] { new Vector2(400, 240), new Vector2(400, -2000), }; var viewport = new Viewport(0, 0, 800, 480); var projectionMatrix = Matrix.CreatePerspectiveFieldOfView(MathHelper.PiOver4, viewport.Width / viewport.Height, 1, 200000); var viewMatrix = Matrix.CreateLookAt(new Vector3(400, 630, 600), new Vector3(400, 345, 0), new Vector3(0, 0, 1)); var worldMatrix = Matrix.Identity; foreach (var screenPosition in screenPositions) { var nearPoint = viewport.Unproject(new Vector3(screenPosition, 0), projectionMatrix, viewMatrix, worldMatrix); var farPoint = viewport.Unproject(new Vector3(screenPosition, 1), projectionMatrix, viewMatrix, worldMatrix); Console.WriteLine("For screen position {0}:", screenPosition); Console.WriteLine(" Projected Near Point = {0}", nearPoint.TruncateZ()); Console.WriteLine(" Projected Far Point = {0}", farPoint.TruncateZ()); Console.WriteLine(); } } The output I get on the console is: For screen position {X:400 Y:240}: Projected Near Point = {X:400 Y:629.571 Z:599.0967} Projected Far Point = {X:392.9302 Y:-83074.98 Z:-175627.9} For screen position {X:400 Y:-2000}: Projected Near Point = {X:400 Y:626.079 Z:600.7554} Projected Far Point = {X:390.2068 Y:-767438.6 Z:148564.2} My question is really twofold: what am I doing wrong with the unprojection such that it varies so wildly and, thus, does not allow me to determine the corresponding world point for my distant screen point? is there a better way altogether to determine the furthermost point in world space given a current world space location, and a directional vector in screen space?

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  • Per-pixel collision detection - why does XNA transform matrix return NaN when adding scaling?

    - by JasperS
    I looked at the TransformCollision sample on MSDN and added the Matrix.CreateTranslation part to a property in my collision detection code but I wanted to add scaling. The code works fine when I leave scaling commented out but when I add it and then do a Matrix.Invert() on the created translation matrix the result is NaN ({NaN,NaN,NaN},{NaN,NaN,NaN},...) Can anyone tell me why this is happening please? Here's the code from the sample: // Build the block's transform Matrix blockTransform = Matrix.CreateTranslation(new Vector3(-blockOrigin, 0.0f)) * // Matrix.CreateScale(block.Scale) * would go here Matrix.CreateRotationZ(blocks[i].Rotation) * Matrix.CreateTranslation(new Vector3(blocks[i].Position, 0.0f)); public static bool IntersectPixels( Matrix transformA, int widthA, int heightA, Color[] dataA, Matrix transformB, int widthB, int heightB, Color[] dataB) { // Calculate a matrix which transforms from A's local space into // world space and then into B's local space Matrix transformAToB = transformA * Matrix.Invert(transformB); // When a point moves in A's local space, it moves in B's local space with a // fixed direction and distance proportional to the movement in A. // This algorithm steps through A one pixel at a time along A's X and Y axes // Calculate the analogous steps in B: Vector2 stepX = Vector2.TransformNormal(Vector2.UnitX, transformAToB); Vector2 stepY = Vector2.TransformNormal(Vector2.UnitY, transformAToB); // Calculate the top left corner of A in B's local space // This variable will be reused to keep track of the start of each row Vector2 yPosInB = Vector2.Transform(Vector2.Zero, transformAToB); // For each row of pixels in A for (int yA = 0; yA < heightA; yA++) { // Start at the beginning of the row Vector2 posInB = yPosInB; // For each pixel in this row for (int xA = 0; xA < widthA; xA++) { // Round to the nearest pixel int xB = (int)Math.Round(posInB.X); int yB = (int)Math.Round(posInB.Y); // If the pixel lies within the bounds of B if (0 <= xB && xB < widthB && 0 <= yB && yB < heightB) { // Get the colors of the overlapping pixels Color colorA = dataA[xA + yA * widthA]; Color colorB = dataB[xB + yB * widthB]; // If both pixels are not completely transparent, if (colorA.A != 0 && colorB.A != 0) { // then an intersection has been found return true; } } // Move to the next pixel in the row posInB += stepX; } // Move to the next row yPosInB += stepY; } // No intersection found return false; }

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