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  • Problem with mathamatical calculation in JQUERY

    - by Param-Ganak
    Hello friends! I have two text boxes. I enter number in one textbox. I write following JQUERY for that textbox which get executed when the focus out from first text box. The JQUERY code takes the entered value from first text box and multiply it by a decimal number 34.95 and display the answer in second text box. The code is doing the calculation little bit ok because when I enter the value 1000 in first text box it gives answer 34950 in second textbox and when I enter the value 100 in first text box it gives answer 3495.0000000000005 in second text box. **Please any one tell me what is the problem. is problem is in my JQUERY code. I also want to show the answer always in decimal point. Answer should always dislply only two digits after decimal point. so How to achieve this too.** This is my JQUERY code. $("#id_pvalue").focusout(function() { q=$("#id_pvalue").val(); var ans=q*34.95; $("#id_tvalue").val(ans); }); Please guide me friends! Thank You!

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  • jQuery script works in Firefox but not in IE. Why am I not surprised?

    - by Ben Tew
    I'm working with the context of a CMS system and trying to turn seperate div's into tabs. You can see it at http://www.wtvynews4.com/test I've kludged together some code from a tutorial site. <script charset="utf-8" type="text/javascript"> jQuery(function() { //When page loads... $("div[ondblclick$='87119417']").attr("id", "87119417"); $("div[ondblclick$='87119482']").attr("id", "87119482"); $("div[ondblclick$='87119672']").attr("id", "87119672"); $("div[ondblclick$='87119727']").attr("id", "87119727"); $("div[ondblclick$='87119812']").attr("id", "87119812"); $("div[ondblclick$='87119417']").addClass("tab_content"); $("div[ondblclick$='87119482']").addClass("tab_content"); $("div[ondblclick$='87119672']").addClass("tab_content"); $("div[ondblclick$='87119727']").addClass("tab_content"); $("div[ondblclick$='87119812']").addClass("tab_content"); $(".tab_content").hide(); //Hide all content $("ul.morenewstabs li:first").addClass("active").show(); //Activate first tab $(".tab_content:first").show(); //Show first tab content //On Click Event $("ul.morenewstabs li").click(function() { $("ul.morenewstabs li").removeClass("active"); //Remove any "active" class $(this).addClass("active"); //Add "active" class to selected tab $(".tab_content").hide(); //Hide all tab content var activeTab = $(this).find("a").attr("href"); //Find the href attribute value to identify the active tab + content $(activeTab).show(); //Fade in the active ID content return false; }); }); </script> Everything works fine in Firefox but not IE. can you provide any assistance? When the page loads the attribute ID's and classes aren't assigned. I tried changing jQuery(function() { to $(document).ready(function() still no luck.

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  • Open new UserControl in the mainWindows

    - by user287964
    Hi I have this snippet public partial class Window1 : Window { public Window1() { InitializeComponent(); } private void ToggleButton_Checked(object sender, RoutedEventArgs e) { switch ((sender as Button).Content.ToString()) { case "UserControl 1": AddItemToContainer(new UserControl1()); break; case "UserControl 2": AddItemToContainer(new UserControl2()); break; case "UserControl 3": AddItemToContainer(new UserControl3()); break; default: break; } } void AddItemToContainer(UIElement _myElement) { Grid.SetColumn(_myElement, 1); HostContainer.Children.Add(_myElement); } } } } With this I can open a new userControl in myMainwindow Let’s say something like adding child to myMainWinodw,Now I’m trying to click on a button from my userControl so I open another userControl that take the place of the first one I explain: I have the mainWindows it has 3 button first one to open the first UserControl the second one to open the second userControl and the third to open the last UserControl,imagine that I opened the first UserControl let’s call it UC1, In the UC1 I have a button to open the second userControl (let’s call it UC2) I like that when I clik the button from the UC1 the UC2 is opened and take the place of the UC1 (of course the UC2 is still a child of myMainWinodw) I have alredy try to call the AddItemToContainer methode from other methode but nothing is happened Any suggestion please

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  • How do i find if an object is before or after a waypoint?

    - by BoMann Andersen
    Im working on a racing game for a school project. Using Visual studio 10 pro, and Irrlicht. Sorry for bad grammar ., and its my first question so not sure if its done right. How i want it to work is that i make waypoints at different points on the track, and then i run my waypoint check to see if a car is past its next waypoint (the next it "needs" to go past), if yes then it updates the next waypoint, else nothing. The way i hope this will work is, i make a vector from n to n+1, then find the vector that is perpendicular to the first vector at n. Then i see if the object is in front or behind that vector. I found a Gamedev.net forumpost that helped me make this function: void Engine::checkWaypoint(Vehicle* vehicle) { btVector3 vector = waypoints[vehicle->nextWaypoint]; // n btVector3 nextVector = waypoints[vehicle->nextWaypoint + 1]; // n+1 vector = nextVector - vector; // First vector btVector3 pos = btVector3(vehicle->position.X,vehicle->position.Y,vehicle->position.Z); float product = vector.dot(pos - waypoints[vehicle->nextWaypoint]); // positiv = before, negative = behind if(product < 0) vehicle->nextWaypoint += 1; } Current bugs with this is: Updates the nextwaypoint more then ones without going past a new point. When it gets to the end and resets, it stops triggering on the first waypoints. So my questions: Is this an good way to do this? Did i do it right?

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  • Pointer and malloc issue

    - by Andy
    I am fairly new to C and am getting stuck with arrays and pointers when they refer to strings. I can ask for input of 2 numbers (ints) and then return the one I want (first number or second number) without any issues. But when I request names and try to return them, the program crashes after I enter the first name and not sure why. In theory I am looking to reserve memory for the first name, and then expand it to include a second name. Can anyone explain why this breaks? Thanks! #include <stdio.h> #include <stdlib.h> void main () { int NumItems = 0; NumItems += 1; char* NameList = malloc(sizeof(char[10])*NumItems); printf("Please enter name #1: \n"); scanf("%9s", NameList[0]); fpurge(stdin); NumItems += 1; NameList = realloc(NameList,sizeof(char[10])*NumItems); printf("Please enter name #2: \n"); scanf("%9s", NameList[1]); fpurge(stdin); printf("The first name is: %s",NameList[0]); printf("The second name is: %s",NameList[1]); return 0; }

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  • XSLT 1 Plain Text Spacing

    - by justkt
    Using Perl's XML::LibXSLT necessitates that I use XSLT 1.0, which means that I am stuck without XSLT 2.0 features. Is there a way that I can still pad text cleanly in a plain-text output from my processing? What I want is: <values> <headers> <header>Header 1</header> <header>Header 2</header> </headers> <value> <one>First value 1</one> <two>First value 2</two> </value> <value> <one>Second value 1</one> <two>Second value 2</two> </value> .... <value> <one>Nth value 1</one> <two>Nth value 2</two> </value> </values> To become Header 1 Header 2 First value 1 First value 2 Second value 1 Second value 2 .... Nth value 1 Nth value 2 I realize that XSLT isn't necessarily ideally suited for this type of formatting, but the data will likely also be formatted in other ways.

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  • Assigning a value to an integer in a C linked list

    - by Drunk On Java
    Hello all. I have a question regarding linked lists. I have the following structs and function for example. struct node { int value; struct node *next; }; struct entrynode { struct node *first; struct node *last; int length; }; void addnode(struct entrynode *entry) { struct node *nextnode = (struct node *)malloc(sizeof(struct node)); int temp; if(entry->first == NULL) { printf("Please enter an integer.\n"); scanf("%d", &temp); nextnode->value = temp; nextnode->next = NULL; entry->first = nextnode; entry->last = nextnode; entry->length++; } else { entry->last->next = nextnode; printf("Please enter an integer.\n"); scanf("%d", nextnode->value); nextnode->next = NULL; entry->last = nextnode; entry->length++; } } In the first part of the if statement, I store input into a temp variable and then assign that to a field in the struct. The else branch, I tried to assign it directly which did not work. How would I go about assigning it directly? Thanks for your time.

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  • thrust::unique_by_key eating up last element

    - by Programmer
    Please consider the below simple code: thrust::device_vector<int> positions(6); thrust::sequence(positions.begin(), positions.end()); thrust::pair<thrust::device_vector<int>::iterator, thrust::device_vector<int>::iterator > end; //copyListOfNgramCounteachdoc contains: 0,1,1,1,1,3 end.first = copyListOfNgramCounteachdoc.begin(); end.second = positions.begin(); for(int i =0 ; i < numDocs; i++){ end= thrust::unique_by_key(end.first, end.first + 3,end.second); } int length = end.first - copyListOfNgramCounteachdoc.begin() ; cout<<"the value of end -s is: "<<length; for(int i =0 ; i< length ; i++){ cout<<copyListOfNgramCounteachdoc[i]; } I expected the output to be 0,1,1,3 of this code; however, the output is 0,1,1. Can anyone let me know what I am missing? Note: the contents of copyListOfNgramCounteachdoc is 0,1,1,1,1,3 . Also the type of copyListOfNgramCounteachdoc is thrust::device_vector<int>.

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  • next previous button in div jquery mobile

    - by satine kianne
    i have a total of 11 div in my app. what i want to do is to display 3 divs in between 2 permanent div it should look like this |first permanent div| |div 1| |div 2| |div 3| |second permanent div| |previous| |next| when i click on next is should look like this |first permanent div| |div 2| |div 3| |div 4| |second permanent div| |previous| |next| and so on. and when im not div 1,2,3 the previous should be disabled and when im no 7,8,9 the next should be disabled. but i cant make it i'm using this fiddle as a sample http://jsfiddle.net/WGkPV/1/ its working but only one div is shown in the center of my two permanent div which is not in my plan.im getting like this |first permanent div| |div 1| |second permanent div| |previous| |next| any suggestion will be taken seriously. here is the code of the fiddle im working on as tutorial $(document).ready(function () { var divs = $('.mydivs>div'); var now = 0; // currently shown div divs.hide().first().show(); $("button[name=next]").click(function (e) { divs.eq(now).hide(); now = (now + 1 < divs.length) ? now + 1 : 0; divs.eq(now).show(); // show next }); $("button[name=prev]").click(function (e) { divs.eq(now).hide(); now = (now > 0) ? now - 1 : divs.length - 1; divs.eq(now).show(); // or .css('display','block'); //console.log(divs.length, now); }); }); <div class="mydivs"> <div>div 1</div> <div>div 2</div> <div>div 3</div> <div>div 4</div> </div>

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  • "pseudo-atomic" operations in C++

    - by dan
    So I'm aware that nothing is atomic in C++. But I'm trying to figure out if there are any "pseudo-atomic" assumptions I can make. The reason is that I want to avoid using mutexes in some simple situations where I only need very weak guarantees. 1) Suppose I have globally defined volatile bool b, which initially I set true. Then I launch a thread which executes a loop while(b) doSomething(); Meanwhile, in another thread, I execute b=true. Can I assume that the first thread will continue to execute? In other words, if b starts out as true, and the first thread checks the value of b at the same time as the second thread assigns b=true, can I assume that the first thread will read the value of b as true? Or is it possible that at some intermediate point of the assignment b=true, the value of b might be read as false? 2) Now suppose that b is initially false. Then the first thread executes bool b1=b; bool b2=b; if(b1 && !b2) bad(); while the second thread executes b=true. Can I assume that bad() never gets called? 3) What about an int or other builtin types: suppose I have volatile int i, which is initially (say) 7, and then I assign i=7. Can I assume that, at any time during this operation, from any thread, the value of i will be equal to 7? 4) I have volatile int i=7, and then I execute i++ from some thread, and all other threads only read the value of i. Can I assume that i never has any value, in any thread, except for either 7 or 8? 5) I have volatile int i, from one thread I execute i=7, and from another I execute i=8. Afterwards, is i guaranteed to be either 7 or 8 (or whatever two values I have chosen to assign)?

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  • problem with jquery each and swich between 2 things

    - by moustafa
    first see this post i got this code $('.yesno').click(function(){ $('.yesno').each(function(i, v){ $(v).removeClass('selected'); }); $(this).addClass('selected'); return false; }); and html this <a href="#"> <span class="Yes yesno">Yes</span> </a> <a href="#"> <span class="No yesno">No</span> no the problem when i make more than one vote iam get very big problem see this <a href="#"> <span class="Yes yesno">Yes</span> </a> <a href="#"> <span class="No yesno">No</span> </a> <a href="#"> <span class="Yes yesno">Yes</span> </a> <a href="#"> <span class="No yesno">No</span> </a> </a> when click first yes its choose the first yes and hwen iam going to the next yes when click its because selected but the first yes because unselected i want make some thin make each yes and know is differant of others

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  • Learning Python else syntax error

    - by user1441016
    Hi I am learning python by doing the practice problems for Open course at MIT 6.00 Intro to Computer Science. I am Trying to do practice problem 1 part 2 create a recursive function to count the instance of key in target. My code so far... from string import * def countSubStringMatchRecursive (target, key,x,s): if (find(target,key)==find(target,key,s)) and (find(target,key)==find(target,key,(find(target,key)))):#if first and last return (1) elif (find(target,key)==find(target,key,s))and (find(target,key)!=find(target,key,(find(target,key)))):#if first but not last x=1 s= find(target,key) return (countSubStringMatchRecursive(target,key,s,x) elif (find(target,key,s))==-1 and (find(target,key)!=find(target,key,s)):#if last but not first return (x+1) elif:(find(target,key,s))!=-1 and (find(target,key)!=find(target,key,s)):#if not last and not first x=x+1 s= find(target,key,s) return (countSubStringMatchRecursive(target,key,s,x) I getting a syntax error at line 8. I would just like to know what I did wrong there. Dont worry about the other mistakes I should be able to get those sorted out. I just Stuck on this. Thanks.

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  • Display TableViews corresponding to segmentedControl in a single tableview without pushing a new view

    - by user1727927
    I have a tableViewController where I have used the Interface Builder to insert a Segmented Controller having two segments. Since by default, first segment is always selected, I am not facing any problem in displaying the tableview corresponding to first segment. However, when I click on the second segment, I want to display another tableView. Here goes the problem. I am calling newTableViewController class on clicking the second segment. Hence, this view is getting pushed instead. Please suggest me a method to have these two tableViews in the main tableView upon clicking the segments. I have used switch case for switching between the segments. Here's the relevant part of the code: This method is in the FirstTableViewController since first segment is by default selected. -(IBAction) segmentedControlChanged { switch(segmentedControl.selectedSegmnentIndex) { case 0: //default first index selected. [tableView setHidden:NO]; break; case 1: NewViewController *controller=[[NewViewController alloc] initWithNibName:@"NewViewController" bundle:nil]; self.navigationController pushViewController:controller animated:YES]; [controller release]; break; default: break; } }

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  • Why isn't the pathspec magic :(exclude) excluding the files I specify from git log's output?

    - by Jubobs
    This is a follow-up to Ignore files in git log -p and is also related to Making 'git log' ignore changes for certain paths. I'm using Git 1.9.2. I'm trying to use the pathspec magic :(exclude) to specify that some patches should not be shown in the output of git log -p. However, patches that I want to exclude still show up in the output. Here is minimal working example that reproduces the situation: cd ~/Desktop mkdir test_exclude cd test_exclude git init mkdir testdir echo "my first cpp file" >testdir/test1.cpp echo "my first xml file" >testdir/test2.xml git add testdir/ git commit -m "added two test files" Now I want to show all patches in my history expect those corresponding to XML files in the testdir folder. Therefore, following VonC's answer, I run git log --patch -- . ":(exclude)testdir/*.xml" but the patch for my testdir/test2.xml file still shows up in the output: commit 37767da1ad4ad5a5c902dfa0c9b95351e8a3b0d9 Author: xxxxxxxxxxxxxxxxxxxxxxxxx Date: Mon Aug 18 12:23:56 2014 +0100 added two test files diff --git a/testdir/test1.cpp b/testdir/test1.cpp new file mode 100644 index 0000000..3a721aa --- /dev/null +++ b/testdir/test1.cpp @@ -0,0 +1 @@ +my first cpp file diff --git a/testdir/test2.xml b/testdir/test2.xml new file mode 100644 index 0000000..8b7ce86 --- /dev/null +++ b/testdir/test2.xml @@ -0,0 +1 @@ +my first xml file What am I doing wrong? What should I do to tell git log -p not to show the patch associated with all XML files in my testdir folder?

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  • How do I display core data on second view controller?

    - by jon
    I am working on my first core data iPhone application. I am using a navigation controller, and the root view controller displays 4 rows. Clicking the first row takes me to a second table view controller. However, when I click the back button, repeat the row tap, click the back button again, and tap the row a third time, I get an error. I have been researching this for a week with no success. I can reproduce the error easily: Create a new Navigation-based Application, use Core Data for storage, call it MyTest which creates MyTestAppDelegate and RootViewController. Add new UIViewController subclass, with UITableViewController and xib, call it ListViewController. Copy code from RootViewController.h and .m to ListViewController.h and .m., changing the file names appropriately. To simplify the code, I removed the trailing “_” from all variables. In RootViewController, I added #import ListViewController.h, set up an array to display 4 rows and navigate to ListViewController when clicking the first row. In ListViewController.m, I added #import MyTestAppDelegate.h” and the following code: - (void)viewDidLoad { [super viewDidLoad]; if (managedObjectContext == nil) { managedObjectContext = [(MyTestAppDelegate *)[[UIApplication sharedApplication] delegate] managedObjectContext]; } .. } The sequence that causes the error is tap row, return, tap row, return, tap row - error. managedObjectContext is synthesized for the third time. I appreciate your patience and your help, as this makes no sense to me. ADDENDUM: I may have a partial solution. http://www.iphonedevsdk.com/forum/iphone-sdk-development/41688-accessing-app-delegates-managed-object-context.html If I do not release the managedObjectContext in the .m file, the error goes away. Is that ok or will that cause me issues? - (void)dealloc { [fetchedResultsController release]; // [managedObjectContext release]; [super dealloc]; } ADDENDUM 2: See solution below. Sorry for the formatting issues - this was my first post.

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  • Pair equal operator overloading for inserting into set

    - by Petwoip
    I am trying to add a pair<int,int> to a set. If a pair shares the same two values as another in the set, it should not be inserted. Here's my non-working code: typedef std::pair<int, int> PairInt; template<> bool std::operator==(const PairInt& l, const PairInt& r) { return (l.first == r.first && l.second == r.second) || (l.first == r.second && l.second == r.first); } int main() { std::set<PairInt> intSet; intSet.insert(PairInt(1,3)); intSet.insert(PairInt(1,4)); intSet.insert(PairInt(1,4)); intSet.insert(PairInt(4,1)); } At the moment, the (4,1) pair gets added even though there is already a (1,4) pair. The final contents of the set are: (1 3) (1 4) (4 1) and I want it to be (1 3) (1 4) I've tried putting breakpoints in the overloaded method, but they never get reached. What have I done wrong?

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  • From Binary to Data Structures

    - by Cédric Menzi
    Table of Contents Introduction PE file format and COFF header COFF file header BaseCoffReader Byte4ByteCoffReader UnsafeCoffReader ManagedCoffReader Conclusion History This article is also available on CodeProject Introduction Sometimes, you want to parse well-formed binary data and bring it into your objects to do some dirty stuff with it. In the Windows world most data structures are stored in special binary format. Either we call a WinApi function or we want to read from special files like images, spool files, executables or may be the previously announced Outlook Personal Folders File. Most specifications for these files can be found on the MSDN Libarary: Open Specification In my example, we are going to get the COFF (Common Object File Format) file header from a PE (Portable Executable). The exact specification can be found here: PECOFF PE file format and COFF header Before we start we need to know how this file is formatted. The following figure shows an overview of the Microsoft PE executable format. Source: Microsoft Our goal is to get the PE header. As we can see, the image starts with a MS-DOS 2.0 header with is not important for us. From the documentation we can read "...After the MS DOS stub, at the file offset specified at offset 0x3c, is a 4-byte...". With this information we know our reader has to jump to location 0x3c and read the offset to the signature. The signature is always 4 bytes that ensures that the image is a PE file. The signature is: PE\0\0. To prove this we first seek to the offset 0x3c, read if the file consist the signature. So we need to declare some constants, because we do not want magic numbers.   private const int PeSignatureOffsetLocation = 0x3c; private const int PeSignatureSize = 4; private const string PeSignatureContent = "PE";   Then a method for moving the reader to the correct location to read the offset of signature. With this method we always move the underlining Stream of the BinaryReader to the start location of the PE signature.   private void SeekToPeSignature(BinaryReader br) { // seek to the offset for the PE signagure br.BaseStream.Seek(PeSignatureOffsetLocation, SeekOrigin.Begin); // read the offset int offsetToPeSig = br.ReadInt32(); // seek to the start of the PE signature br.BaseStream.Seek(offsetToPeSig, SeekOrigin.Begin); }   Now, we can check if it is a valid PE image by reading of the next 4 byte contains the content PE.   private bool IsValidPeSignature(BinaryReader br) { // read 4 bytes to get the PE signature byte[] peSigBytes = br.ReadBytes(PeSignatureSize); // convert it to a string and trim \0 at the end of the content string peContent = Encoding.Default.GetString(peSigBytes).TrimEnd('\0'); // check if PE is in the content return peContent.Equals(PeSignatureContent); }   With this basic functionality we have a good base reader class to try the different methods of parsing the COFF file header. COFF file header The COFF header has the following structure: Offset Size Field 0 2 Machine 2 2 NumberOfSections 4 4 TimeDateStamp 8 4 PointerToSymbolTable 12 4 NumberOfSymbols 16 2 SizeOfOptionalHeader 18 2 Characteristics If we translate this table to code, we get something like this:   [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)] public struct CoffHeader { public MachineType Machine; public ushort NumberOfSections; public uint TimeDateStamp; public uint PointerToSymbolTable; public uint NumberOfSymbols; public ushort SizeOfOptionalHeader; public Characteristic Characteristics; } BaseCoffReader All readers do the same thing, so we go to the patterns library in our head and see that Strategy pattern or Template method pattern is sticked out in the bookshelf. I have decided to take the template method pattern in this case, because the Parse() should handle the IO for all implementations and the concrete parsing should done in its derived classes.   public CoffHeader Parse() { using (var br = new BinaryReader(File.Open(_fileName, FileMode.Open, FileAccess.Read, FileShare.Read))) { SeekToPeSignature(br); if (!IsValidPeSignature(br)) { throw new BadImageFormatException(); } return ParseInternal(br); } } protected abstract CoffHeader ParseInternal(BinaryReader br);   First we open the BinaryReader, seek to the PE signature then we check if it contains a valid PE signature and rest is done by the derived implementations. Byte4ByteCoffReader The first solution is using the BinaryReader. It is the general way to get the data. We only need to know which order, which data-type and its size. If we read byte for byte we could comment out the first line in the CoffHeader structure, because we have control about the order of the member assignment.   protected override CoffHeader ParseInternal(BinaryReader br) { CoffHeader coff = new CoffHeader(); coff.Machine = (MachineType)br.ReadInt16(); coff.NumberOfSections = (ushort)br.ReadInt16(); coff.TimeDateStamp = br.ReadUInt32(); coff.PointerToSymbolTable = br.ReadUInt32(); coff.NumberOfSymbols = br.ReadUInt32(); coff.SizeOfOptionalHeader = (ushort)br.ReadInt16(); coff.Characteristics = (Characteristic)br.ReadInt16(); return coff; }   If the structure is as short as the COFF header here and the specification will never changed, there is probably no reason to change the strategy. But if a data-type will be changed, a new member will be added or ordering of member will be changed the maintenance costs of this method are very high. UnsafeCoffReader Another way to bring the data into this structure is using a "magically" unsafe trick. As above, we know the layout and order of the data structure. Now, we need the StructLayout attribute, because we have to ensure that the .NET Runtime allocates the structure in the same order as it is specified in the source code. We also need to enable "Allow unsafe code (/unsafe)" in the project's build properties. Then we need to add the following constructor to the CoffHeader structure.   [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)] public struct CoffHeader { public CoffHeader(byte[] data) { unsafe { fixed (byte* packet = &data[0]) { this = *(CoffHeader*)packet; } } } }   The "magic" trick is in the statement: this = *(CoffHeader*)packet;. What happens here? We have a fixed size of data somewhere in the memory and because a struct in C# is a value-type, the assignment operator = copies the whole data of the structure and not only the reference. To fill the structure with data, we need to pass the data as bytes into the CoffHeader structure. This can be achieved by reading the exact size of the structure from the PE file.   protected override CoffHeader ParseInternal(BinaryReader br) { return new CoffHeader(br.ReadBytes(Marshal.SizeOf(typeof(CoffHeader)))); }   This solution is the fastest way to parse the data and bring it into the structure, but it is unsafe and it could introduce some security and stability risks. ManagedCoffReader In this solution we are using the same approach of the structure assignment as above. But we need to replace the unsafe part in the constructor with the following managed part:   [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)] public struct CoffHeader { public CoffHeader(byte[] data) { IntPtr coffPtr = IntPtr.Zero; try { int size = Marshal.SizeOf(typeof(CoffHeader)); coffPtr = Marshal.AllocHGlobal(size); Marshal.Copy(data, 0, coffPtr, size); this = (CoffHeader)Marshal.PtrToStructure(coffPtr, typeof(CoffHeader)); } finally { Marshal.FreeHGlobal(coffPtr); } } }     Conclusion We saw that we can parse well-formed binary data to our data structures using different approaches. The first is probably the clearest way, because we know each member and its size and ordering and we have control about the reading the data for each member. But if add member or the structure is going change by some reason, we need to change the reader. The two other solutions use the approach of the structure assignment. In the unsafe implementation we need to compile the project with the /unsafe option. We increase the performance, but we get some security risks.

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  • Parallelism in .NET – Part 5, Partitioning of Work

    - by Reed
    When parallelizing any routine, we start by decomposing the problem.  Once the problem is understood, we need to break our work into separate tasks, so each task can be run on a different processing element.  This process is called partitioning. Partitioning our tasks is a challenging feat.  There are opposing forces at work here: too many partitions adds overhead, too few partitions leaves processors idle.  Trying to work the perfect balance between the two extremes is the goal for which we should aim.  Luckily, the Task Parallel Library automatically handles much of this process.  However, there are situations where the default partitioning may not be appropriate, and knowledge of our routines may allow us to guide the framework to making better decisions. First off, I’d like to say that this is a more advanced topic.  It is perfectly acceptable to use the parallel constructs in the framework without considering the partitioning taking place.  The default behavior in the Task Parallel Library is very well-behaved, even for unusual work loads, and should rarely be adjusted.  I have found few situations where the default partitioning behavior in the TPL is not as good or better than my own hand-written partitioning routines, and recommend using the defaults unless there is a strong, measured, and profiled reason to avoid using them.  However, understanding partitioning, and how the TPL partitions your data, helps in understanding the proper usage of the TPL. I indirectly mentioned partitioning while discussing aggregation.  Typically, our systems will have a limited number of Processing Elements (PE), which is the terminology used for hardware capable of processing a stream of instructions.  For example, in a standard Intel i7 system, there are four processor cores, each of which has two potential hardware threads due to Hyperthreading.  This gives us a total of 8 PEs – theoretically, we can have up to eight operations occurring concurrently within our system. In order to fully exploit this power, we need to partition our work into Tasks.  A task is a simple set of instructions that can be run on a PE.  Ideally, we want to have at least one task per PE in the system, since fewer tasks means that some of our processing power will be sitting idle.  A naive implementation would be to just take our data, and partition it with one element in our collection being treated as one task.  When we loop through our collection in parallel, using this approach, we’d just process one item at a time, then reuse that thread to process the next, etc.  There’s a flaw in this approach, however.  It will tend to be slower than necessary, often slower than processing the data serially. The problem is that there is overhead associated with each task.  When we take a simple foreach loop body and implement it using the TPL, we add overhead.  First, we change the body from a simple statement to a delegate, which must be invoked.  In order to invoke the delegate on a separate thread, the delegate gets added to the ThreadPool’s current work queue, and the ThreadPool must pull this off the queue, assign it to a free thread, then execute it.  If our collection had one million elements, the overhead of trying to spawn one million tasks would destroy our performance. The answer, here, is to partition our collection into groups, and have each group of elements treated as a single task.  By adding a partitioning step, we can break our total work into small enough tasks to keep our processors busy, but large enough tasks to avoid overburdening the ThreadPool.  There are two clear, opposing goals here: Always try to keep each processor working, but also try to keep the individual partitions as large as possible. When using Parallel.For, the partitioning is always handled automatically.  At first, partitioning here seems simple.  A naive implementation would merely split the total element count up by the number of PEs in the system, and assign a chunk of data to each processor.  Many hand-written partitioning schemes work in this exactly manner.  This perfectly balanced, static partitioning scheme works very well if the amount of work is constant for each element.  However, this is rarely the case.  Often, the length of time required to process an element grows as we progress through the collection, especially if we’re doing numerical computations.  In this case, the first PEs will finish early, and sit idle waiting on the last chunks to finish.  Sometimes, work can decrease as we progress, since previous computations may be used to speed up later computations.  In this situation, the first chunks will be working far longer than the last chunks.  In order to balance the workload, many implementations create many small chunks, and reuse threads.  This adds overhead, but does provide better load balancing, which in turn improves performance. The Task Parallel Library handles this more elaborately.  Chunks are determined at runtime, and start small.  They grow slowly over time, getting larger and larger.  This tends to lead to a near optimum load balancing, even in odd cases such as increasing or decreasing workloads.  Parallel.ForEach is a bit more complicated, however. When working with a generic IEnumerable<T>, the number of items required for processing is not known in advance, and must be discovered at runtime.  In addition, since we don’t have direct access to each element, the scheduler must enumerate the collection to process it.  Since IEnumerable<T> is not thread safe, it must lock on elements as it enumerates, create temporary collections for each chunk to process, and schedule this out.  By default, it uses a partitioning method similar to the one described above.  We can see this directly by looking at the Visual Partitioning sample shipped by the Task Parallel Library team, and available as part of the Samples for Parallel Programming.  When we run the sample, with four cores and the default, Load Balancing partitioning scheme, we see this: The colored bands represent each processing core.  You can see that, when we started (at the top), we begin with very small bands of color.  As the routine progresses through the Parallel.ForEach, the chunks get larger and larger (seen by larger and larger stripes). Most of the time, this is fantastic behavior, and most likely will out perform any custom written partitioning.  However, if your routine is not scaling well, it may be due to a failure in the default partitioning to handle your specific case.  With prior knowledge about your work, it may be possible to partition data more meaningfully than the default Partitioner. There is the option to use an overload of Parallel.ForEach which takes a Partitioner<T> instance.  The Partitioner<T> class is an abstract class which allows for both static and dynamic partitioning.  By overriding Partitioner<T>.SupportsDynamicPartitions, you can specify whether a dynamic approach is available.  If not, your custom Partitioner<T> subclass would override GetPartitions(int), which returns a list of IEnumerator<T> instances.  These are then used by the Parallel class to split work up amongst processors.  When dynamic partitioning is available, GetDynamicPartitions() is used, which returns an IEnumerable<T> for each partition.  If you do decide to implement your own Partitioner<T>, keep in mind the goals and tradeoffs of different partitioning strategies, and design appropriately. The Samples for Parallel Programming project includes a ChunkPartitioner class in the ParallelExtensionsExtras project.  This provides example code for implementing your own, custom allocation strategies, including a static allocator of a given chunk size.  Although implementing your own Partitioner<T> is possible, as I mentioned above, this is rarely required or useful in practice.  The default behavior of the TPL is very good, often better than any hand written partitioning strategy.

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  • SQL SERVER – How to Recover SQL Database Data Deleted by Accident

    - by Pinal Dave
    In Repair a SQL Server database using a transaction log explorer, I showed how to use ApexSQL Log, a SQL Server transaction log viewer, to recover a SQL Server database after a disaster. In this blog, I’ll show you how to use another SQL Server disaster recovery tool from ApexSQL in a situation when data is accidentally deleted. You can download ApexSQL Recover here, install, and play along. With a good SQL Server disaster recovery strategy, data recovery is not a problem. You have a reliable full database backup with valid data, a full database backup and subsequent differential database backups, or a full database backup and a chain of transaction log backups. But not all situations are ideal. Here we’ll address some sub-optimal scenarios, where you can still successfully recover data. If you have only a full database backup This is the least optimal SQL Server disaster recovery strategy, as it doesn’t ensure minimal data loss. For example, data was deleted on Wednesday. Your last full database backup was created on Sunday, three days before the records were deleted. By using the full database backup created on Sunday, you will be able to recover SQL database records that existed in the table on Sunday. If there were any records inserted into the table on Monday or Tuesday, they will be lost forever. The same goes for records modified in this period. This method will not bring back modified records, only the old records that existed on Sunday. If you restore this full database backup, all your changes (intentional and accidental) will be lost and the database will be reverted to the state it had on Sunday. What you have to do is compare the records that were in the table on Sunday to the records on Wednesday, create a synchronization script, and execute it against the Wednesday database. If you have a full database backup followed by differential database backups Let’s say the situation is the same as in the example above, only you create a differential database backup every night. Use the full database backup created on Sunday, and the last differential database backup (created on Tuesday). In this scenario, you will lose only the data inserted and updated after the differential backup created on Tuesday. If you have a full database backup and a chain of transaction log backups This is the SQL Server disaster recovery strategy that provides minimal data loss. With a full chain of transaction logs, you can recover the SQL database to an exact point in time. To provide optimal results, you have to know exactly when the records were deleted, because restoring to a later point will not bring back the records. This method requires restoring the full database backup first. If you have any differential log backup created after the last full database backup, restore the most recent one. Then, restore transaction log backups, one by one, it the order they were created starting with the first created after the restored differential database backup. Now, the table will be in the state before the records were deleted. You have to identify the deleted records, script them and run the script against the original database. Although this method is reliable, it is time-consuming and requires a lot of space on disk. How to easily recover deleted records? The following solution enables you to recover SQL database records even if you have no full or differential database backups and no transaction log backups. To understand how ApexSQL Recover works, I’ll explain what happens when table data is deleted. Table data is stored in data pages. When you delete table records, they are not immediately deleted from the data pages, but marked to be overwritten by new records. Such records are not shown as existing anymore, but ApexSQL Recover can read them and create undo script for them. How long will deleted records stay in the MDF file? It depends on many factors, as time passes it’s less likely that the records will not be overwritten. The more transactions occur after the deletion, the more chances the records will be overwritten and permanently lost. Therefore, it’s recommended to create a copy of the database MDF and LDF files immediately (if you cannot take your database offline until the issue is solved) and run ApexSQL Recover on them. Note that a full database backup will not help here, as the records marked for overwriting are not included in the backup. First, I’ll delete some records from the Person.EmailAddress table in the AdventureWorks database.   I can delete these records in SQL Server Management Studio, or execute a script such as DELETE FROM Person.EmailAddress WHERE BusinessEntityID BETWEEN 70 AND 80 Then, I’ll start ApexSQL Recover and select From DELETE operation in the Recovery tab.   In the Select the database to recover step, first select the SQL Server instance. If it’s not shown in the drop-down list, click the Server icon right to the Server drop-down list and browse for the SQL Server instance, or type the instance name manually. Specify the authentication type and select the database in the Database drop-down list.   In the next step, you’re prompted to add additional data sources. As this can be a tricky step, especially for new users, ApexSQL Recover offers help via the Help me decide option.   The Help me decide option guides you through a series of questions about the database transaction log and advises what files to add. If you know that you have no transaction log backups or detached transaction logs, or the online transaction log file has been truncated after the data was deleted, select No additional transaction logs are available. If you know that you have transaction log backups that contain the delete transactions you want to recover, click Add transaction logs. The online transaction log is listed and selected automatically.   Click Add if to add transaction log backups. It would be best if you have a full transaction log chain, as explained above. The next step for this option is to specify the time range.   Selecting a small time range for the time of deletion will create the recovery script just for the accidentally deleted records. A wide time range might script the records deleted on purpose, and you don’t want that. If needed, you can check the script generated and manually remove such records. After that, for all data sources options, the next step is to select the tables. Be careful here, if you deleted some data from other tables on purpose, and don’t want to recover them, don’t select all tables, as ApexSQL Recover will create the INSERT script for them too.   The next step offers two options: to create a recovery script that will insert the deleted records back into the Person.EmailAddress table, or to create a new database, create the Person.EmailAddress table in it, and insert the deleted records. I’ll select the first one.   The recovery process is completed and 11 records are found and scripted, as expected.   To see the script, click View script. ApexSQL Recover has its own script editor, where you can review, modify, and execute the recovery script. The insert into statements look like: INSERT INTO Person.EmailAddress( BusinessEntityID, EmailAddressID, EmailAddress, rowguid, ModifiedDate) VALUES( 70, 70, N'[email protected]' COLLATE SQL_Latin1_General_CP1_CI_AS, 'd62c5b4e-c91f-403f-b630-7b7e0fda70ce', '20030109 00:00:00.000' ); To execute the script, click Execute in the menu.   If you want to check whether the records are really back, execute SELECT * FROM Person.EmailAddress WHERE BusinessEntityID BETWEEN 70 AND 80 As shown, ApexSQL Recover recovers SQL database data after accidental deletes even without the database backup that contains the deleted data and relevant transaction log backups. ApexSQL Recover reads the deleted data from the database data file, so this method can be used even for databases in the Simple recovery model. Besides recovering SQL database records from a DELETE statement, ApexSQL Recover can help when the records are lost due to a DROP TABLE, or TRUNCATE statement, as well as repair a corrupted MDF file that cannot be attached to as SQL Server instance. You can find more information about how to recover SQL database lost data and repair a SQL Server database on ApexSQL Solution center. There are solutions for various situations when data needs to be recovered. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Backup and Restore, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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  • CodePlex Daily Summary for Monday, June 14, 2010

    CodePlex Daily Summary for Monday, June 14, 2010New ProjectsBD File Hash: BD File Hash is a convenient file hash and hash compare tool for Windows which currently works with MD5, SHA-1, and SHA-256 algorithms. FileScan: This is an application that searches through a drive or directory structure for files matching a filter. This project was converted from VB to ...genesis9: genesis9HeinanOS: HeinanOS is an operating system developed mainly in C++. HeinanOS is a light OS (1.44 MB image) with a lot of capabilites and many more are being ...MediaBrowserWS - Creates a Web Service for the popular MediaBrowser plugin: Creates a web service in Media Center for accessing your MediaBrowser collection. Allows for external devices (Tablets/phones/laptops) to access a ...MME: New Edition of Managed Menu Extensions for Visual Studio 2010 The Main goal of "MME" is to provide easy access to adding Right Click menus in the ...MVMMapper: Generate the ViewModel and its mapping to the Model when implementing MVVM in .NET. Developed using T4 templates. Current version supports Silver...ProjectArDotNet: Si te agarro te parto! Si te agarro te emperno no me importa que seas menor de edad!Scriptagility for DotNetNuke: Scriptagility is a DotNetNuke module for Javascript developers. This module provides dynamic client scripting infrastructure for developing javascr...simpleLinux Distro: SimpleLinux. is a Linux distributions that is easy to use. Simple Linux website: http://simplelinux.tkTag Cloud Control for asp.net: Tag Cloud Control for asp.net allows the user to display the most important keywords to display in tag cloud. Each Tag has it own navigation url to...thefreeimdb: fsadie qwUppityUp: UppityUp is a simple and light-weight tray application which monitors a remote server and shows a notification when it comes online. This is usefu...Vivid3D 2 - DirectX 10 3D ToolKit: The sequel to my first ever engine wrote several years ago. It is not based on it in anyway. VSIDev: VSI DevXTQXK_WORK: Actionscript 3.0东坡博客: 这是一个ASP。net mvc 2博客。New Releases.NET Extensions - Extension Methods Library: Release 2010.08: Added extension methods for Bitmap manipulation (scaling for now): - Bitmap.ScaleToSize() - Bitmap.ScaleToSizeProportional() - Bitmap.ScaleProport...Black Falcon Software's Database Data-Access-Layers: “SQLHELPER”, “ORAHELPER” - Handling Binary Data: See attached document...BTech Networking Library: BTech Networking Library: Same as pervious just new namespace, extended networking coming soon!!!Community Forums NNTP bridge: Community Forums NNTP Bridge V37: Release of the Community Forums NNTP Bridge to access the social and anwsers MS forums with a single, open source NNTP bridge. This release has ad...Generic Entity Model 2: GEM2 build 54383: This is second BETA release of GEM2! Please see source code change sets for updates! Following implementation is not included in this release: My...Hades: Projet Hadès - Official Demo - Version 0.1.0 Beta: ---------------------------------------------------------------------------- - Projet Hadès - Official Demo - Version 0.1.0 Beta ------------------...HeinanOS: HeinanOS M1 Source Code: You can download HeinanOS M1 Source Code and contribute to HeinanOS development! Be aware that you should not use this code for your own systems! ...HeinanOS: Milestone 1: This is the first major release for HeinanOS 1.0 Please note this is a PRE-RELEASE! This release includes the following features: -Bootable DOS-...HKGolden Express: HKGoldenExpress (Build 201006131900): New features: (None) Bug fix: Incorrect message submit date of message/ replies. (Note: Showing message submit date is enabled since Build 20100...HKGolden Express: HKGoldenExpress (Build 201006140110): New features: (None) Bug fix: (None) Improvements: (None) Other changes: Set time zone of message date as Hong Kong. Adjusted the format of messa...MediaCoder.NET: MediaCoder.NET v1.0 Beta 1.5: Installer file for MediaCoder.NET v1.0 beta 1.5. Now converts multiple files.MME: First release: Features of this release 1. One installer MME.msi. However you can also install MMEMenuManagerSetup.vsix which installs a project template that e...MSBuild Launch Pad (mPad): 1.1 Beta 1: Platform selection box is added.MVMMapper: MVMMapper Release v 1.0.1: This release has no downloadable documentation. Please use the Documentation section to get started.NginxTray: NginxTray 0.7 RC2: NginxTray 0.7 RC2PowerAuras: PowerAuras-3.0.0K-beta3: New Auras: Item Name Equipment Slot Tracking Changes from beta1 5 new aura textures Fixed Tracking bug Added graphical equipment slot sele...PowerAuras: PowerAuras-3.0.0K-beta4: New Auras: Item Name Equipment Slot Tracking Changes from beta1 5 new aura textures Fixed Tracking bug Added graphical equipment slot sele...Scriptagility for DotNetNuke: Scriptagility 1.0 (Beta): Initial public release please evaluate and feedbackSharpDevelop: SharpDevelop 4.0 Beta 1: Release notes: http://community.sharpdevelop.net/forums/t/11388.aspxsimpleLinux Distro: Project X3: This is an example of download for simpleLinuxSOAPI - StackOverflow API Parser/Wrapper Generator: SOAPI Beta 3: The SOAPI Beta 3 download will be made availabe later today when the initial documentation is complete. The previously available Beta 1 download h...Sofa: Initial release V1.0: This is the first release of Sofa. As it is made of code being previously used, as we tested it is a stable release. But bugs are always possible,...Tag Cloud Control for asp.net: Tag Cloud Control for asp.net: Tag Cloud Control for asp.net allows the user to display the most important keywords to display in tag cloud. Each Tag has it own navigation url to...UppityUp: UppityUp v0.1: First functional version, supports monitoring availability by ping (ICMP) requests. Fit for general use. Consists of one standalone .exe file - no...VCC: Latest build, v2.1.30613.0: Automatic drop of latest buildWindStyle ExifInfo for Windows Live Writer: 1.1.0.0: Add: Multiple Language(English and Simplified Chinese); Add: Insert multiple files; Fix: Error when insert pictures without Exif info; Update: Icon...Work Recorder - Hold on own time!: WorkRecorder 1.2: +Add a whole day chartXsltDb - DotNetNuke Module Builder: 01.01.24: Syntax highlighting delivered!New samples for RadControls. On single page you can find RadTreeView, RadRating, RadChart, RadFormDecorator, RadEdito...xUnit.net Contrib: xunitcontrib 0.4 (ReSharper 5.0 RTM + dotCover): xunitcontrib release 0.4 (ReSharper runner) This release provides a test runner plugin for Resharper 5.0, 4.5 and 4.1, targetting all versions of x...Most Popular ProjectsCommunity Forums NNTP bridgeRIA Services EssentialsNeatUploadBxf (Basic XAML Framework)Agile Personal Development Methodology.NET Transactional File ManagerSOLID by exampleASP.NET MVC Time PlannerWEI ShareSiverlight ProjectMost Active ProjectsjQuery Library for SharePoint Web Servicespatterns & practices – Enterprise LibraryNB_Store - Free DotNetNuke Ecommerce Catalog ModuleRhyduino - Arduino and Managed CodeCommunity Forums NNTP bridgeCassandraemonBlogEngine.NETLightweight Fluent WorkflowMediaCoder.NETAndrew's XNA Helpers

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  • Flashing your Windows Phone Dummies

    - by Martin Hinshelwood
    The rate at which vendors release new updates for the HD2 is ridiculously slow. You have to wait for Microsoft to release the new OS, then you wait for HTC to build it into a ROM, and then you have to wait up to 6 months for your operator to badly customise it for their network. Once Windows Phone 7 is released this problem should go away as Microsoft is likely to be able to update the phone over the air, but what do we do until then? I want Windows Mobile 6.5.5 now!   I’m an early adopter. If there is a new version of something then that’s the version I want. As long as you accept that you are using something on a “let the early adopter beware” and accept that there may be bugs, sometimes serious crippling bugs the go for it. Note that I won't be responsible if you end up bricking your phone, unlocking or flashing your radio or ROM can be risky. If you follow the instructions then you should be fine, I've flashed my phones (SPV, M300, M1000, M2000, M3100, TyTN, TyTN 2, HD2) hundreds of times without any problems! I have been using Windows Mobile 6.5.5 before it was called 6.5.5 and for long enough that I don’t even remember when I first started using it. I was using it on my HTC TyTN 2 before I got an HD2 a couple of months before Christmas, and the first custom ROM’s for the HD2 were a couple of months after that. I always update to the latest ROM that I like, and occasionally I go back to the stock ROM’s to have a look see, but I am always disappointed. Terms: Soft Reset: Same as pulling out the battery, but is like a reboot for your phone Hard Reset: Reinstalls the Operating system from the Image that is stored on it ROM: This is Image that is loaded onto your phone and it is used to reinstall your phone whenever you do a “hard reset”. Stock ROM: A ROM from the original vendor… So HTC Cook a ROM: Referring to Cooking a ROM is the process a ROM developer goes through to take all of the parts (OS, Drivers and Applications) that make up a running phone and compiling them into a ROM. ROM Kitchen: A place where you get an SDK and all the component parts of the phone: OD, Drivers and Application. There are usually lots of Tools for making it easier to compile and build the image. Flashing: The process of updating one of the layers of your phone with a new layer Bricked: This is what happens when flashing goes wrong. Your phone is now good for only one thing… stopping paper blowing away in a windy place. You can “cook” you own ROM using one of the many good “ROM Kitchens” or you can use a ROM built and tested by someone else. I have cooked my own ROM before, and while the tutorials are good, it is a lot of hassle. You can only Flash new ROM’s that are specifically for your phone only so find a ROM for your phone and XDA Developers is the best place to look. It has a forum based structure and you can find your phone quite easily. XDA Developer Forum Installing a new ROM does have its risks. In the past there have been stories about phones being “bricked” but I have not heard of a bricked phone for quite some years. if you follow the instructions carefully you should not have any problems. note: Most of the tools are written by people for whom English is not their first language to you will need concentrate hard to understand some of the instructions. Have you ever read a manual that was just literally translated from another language? Enough said… There are a number of layers on your phone that you will need to know about: SPL: This is the lowest level, like a BIOS on a PC and is the Operating Systems gateway to the hardware Radio: I think of this as the hardware drivers, and you will need a different Radio for CDMA than GSM networks ROM: This is like your Windows CD, but it is stored internally to the Phone. Flashing your phone consists of replacing one Image with another and then wiping your phone and automatically reinstall from the Image. Sometimes when you download an Image wither it is for a Radio or for ROM you only get a file called *.nbh. What do you do with this? Well you need an RUU application to push that Image to your phone. The RUU’s are different per phone, but there is a CustomRUU for the HD2 that will update your phone with any *.nbh placed in the same directory. Download and Instructions for CustomRUU #1 Flash HardSPL An SPL is kind of like a BIOS, and the default one has checks to make sure that you are only installing a signed ROM. This would prevent you from installing one that comes from any other source but the vendor. NOTE: Installing a HARD SPL invalidates your warranty so remember to Flash your phone with a “stock” vendor ROM before trying to send your phone in for repairs. Is the warranty reinstated when you go back to a stock ROM? I don’t know… Updating your SPL to a HardSPL effectively unlocks your phone so you can install anything you like. I would recommend the HardSPL2. Download and Instructions for HardSPL2 #2 Task29 One of the problems that has been seen on the HD2 when flashing new ROM’s is that things are left over from the old ROM. For a while the recommendation was to Flash a stock ROM first, but some clever cookies have come up with “Task29” which formats your phone first. After running this your phone will be blank and will only boot to the white HTC logo and no further. You should follow the instructions and reboot (remove battery) and hold down the “volume down” button while turning you HD2 on to enter the bootloader. From here you can run CustomRUU once the USB message appears. Download and Instructions for Task29 #2 Flash Radio You may need to play around with this one, there is no good and bad version and the latest is not always the best. You know that annoying thing when you hit “end call” on your phone and nothing happens? Well that's down to the Radio. Get this version right for you and you may even be able to make calls. From a Windows Mobile as well Download There are no instructions here, but they are the same as th ROM, but you use this *.nbh file. #3 Flash ROM If you have gotten this far then you are probably a pro by now Just download the latest ROM below and Flash to your phone. I have been really impressed by the Artemis line of ROM’s but it is no way the only choice. I like this one as the developer builds them as close to the stock ROM as possible while updating to the latest of everything. Download and Instructions for  Artemis HD2 vXX Conclusion While updating your ROM is not for the faint hearted it provides more options than the Stock ROM’s and quicker feature updates than waiting… Technorati Tags: WM6

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  • Is Berkeley DB a NoSQL solution?

    - by Gregory Burd
    Berkeley DB is a library. To use it to store data you must link the library into your application. You can use most programming languages to access the API, the calls across these APIs generally mimic the Berkeley DB C-API which makes perfect sense because Berkeley DB is written in C. The inspiration for Berkeley DB was the DBM library, a part of the earliest versions of UNIX written by AT&T's Ken Thompson in 1979. DBM was a simple key/value hashtable-based storage library. In the early 1990s as BSD UNIX was transitioning from version 4.3 to 4.4 and retrofitting commercial code owned by AT&T with unencumbered code, it was the future founders of Sleepycat Software who wrote libdb (aka Berkeley DB) as the replacement for DBM. The problem it addressed was fast, reliable local key/value storage. At that time databases almost always lived on a single node, even the most sophisticated databases only had simple fail-over two node solutions. If you had a lot of data to store you would choose between the few commercial RDBMS solutions or to write your own custom solution. Berkeley DB took the headache out of the custom approach. These basic market forces inspired other DBM implementations. There was the "New DBM" (ndbm) and the "GNU DBM" (GDBM) and a few others, but the theme was the same. Even today TokyoCabinet calls itself "a modern implementation of DBM" mimicking, and improving on, something first created over thirty years ago. In the mid-1990s, DBM was the name for what you needed if you were looking for fast, reliable local storage. Fast forward to today. What's changed? Systems are connected over fast, very reliable networks. Disks are cheep, fast, and capable of storing huge amounts of data. CPUs continued to follow Moore's Law, processing power that filled a room in 1990 now fits in your pocket. PCs, servers, and other computers proliferated both in business and the personal markets. In addition to the new hardware entire markets, social systems, and new modes of interpersonal communication moved onto the web and started evolving rapidly. These changes cause a massive explosion of data and a need to analyze and understand that data. Taken together this resulted in an entirely different landscape for database storage, new solutions were needed. A number of novel solutions stepped up and eventually a category called NoSQL emerged. The new market forces inspired the CAP theorem and the heated debate of BASE vs. ACID. But in essence this was simply the market looking at what to trade off to meet these new demands. These new database systems shared many qualities in common. There were designed to address massive amounts of data, millions of requests per second, and scale out across multiple systems. The first large-scale and successful solution was Dynamo, Amazon's distributed key/value database. Dynamo essentially took the next logical step and added a twist. Dynamo was to be the database of record, it would be distributed, data would be partitioned across many nodes, and it would tolerate failure by avoiding single points of failure. Amazon did this because they recognized that the majority of the dynamic content they provided to customers visiting their web store front didn't require the services of an RDBMS. The queries were simple, key/value look-ups or simple range queries with only a few queries that required more complex joins. They set about to use relational technology only in places where it was the best solution for the task, places like accounting and order fulfillment, but not in the myriad of other situations. The success of Dynamo, and it's design, inspired the next generation of Non-SQL, distributed database solutions including Cassandra, Riak and Voldemort. The problem their designers set out to solve was, "reliability at massive scale" so the first focal point was distributed database algorithms. Underneath Dynamo there is a local transactional database; either Berkeley DB, Berkeley DB Java Edition, MySQL or an in-memory key/value data structure. Dynamo was an evolution of local key/value storage onto networks. Cassandra, Riak, and Voldemort all faced similar design decisions and one, Voldemort, choose Berkeley DB Java Edition for it's node-local storage. Riak at first was entirely in-memory, but has recently added write-once, append-only log-based on-disk storage similar type of storage as Berkeley DB except that it is based on a hash table which must reside entirely in-memory rather than a btree which can live in-memory or on disk. Berkeley DB evolved too, we added high availability (HA) and a replication manager that makes it easy to setup replica groups. Berkeley DB's replication doesn't partitioned the data, every node keeps an entire copy of the database. For consistency, there is a single node where writes are committed first - a master - then those changes are delivered to the replica nodes as log records. Applications can choose to wait until all nodes are consistent, or fire and forget allowing Berkeley DB to eventually become consistent. Berkeley DB's HA scales-out quite well for read-intensive applications and also effectively eliminates the central point of failure by allowing replica nodes to be elected (using a PAXOS algorithm) to mastership if the master should fail. This implementation covers a wide variety of use cases. MemcacheDB is a server that implements the Memcache network protocol but uses Berkeley DB for storage and HA to replicate the cache state across all the nodes in the cache group. Google Accounts, the user authentication layer for all Google properties, was until recently running Berkeley DB HA. That scaled to a globally distributed system. That said, most NoSQL solutions try to partition (shard) data across nodes in the replication group and some allow writes as well as reads at any node, Berkeley DB HA does not. So, is Berkeley DB a "NoSQL" solution? Not really, but it certainly is a component of many of the existing NoSQL solutions out there. Forgetting all the noise about how NoSQL solutions are complex distributed databases when you boil them down to a single node you still have to store the data to some form of stable local storage. DBMs solved that problem a long time ago. NoSQL has more to do with the layers on top of the DBM; the distributed, sometimes-consistent, partitioned, scale-out storage that manage key/value or document sets and generally have some form of simple HTTP/REST-style network API. Does Berkeley DB do that? Not really. Is Berkeley DB a "NoSQL" solution today? Nope, but it's the most robust solution on which to build such a system. Re-inventing the node-local data storage isn't easy. A lot of people are starting to come to appreciate the sophisticated features found in Berkeley DB, even mimic them in some cases. Could Berkeley DB grow into a NoSQL solution? Absolutely. Our key/value API could be extended over the net using any of a number of existing network protocols such as memcache or HTTP/REST. We could adapt our node-local data partitioning out over replicated nodes. We even have a nice query language and cost-based query optimizer in our BDB XML product that we could reuse were we to build out a document-based NoSQL-style product. XML and JSON are not so different that we couldn't adapt one to work with the other interchangeably. Without too much effort we could add what's missing, we could jump into this No SQL market withing a single product development cycle. Why isn't Berkeley DB already a NoSQL solution? Why aren't we working on it? Why indeed...

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  • How to Organize a Programming Language Club

    - by Ben Griswold
    I previously noted that we started a language club at work.  You know, I searched around but I couldn’t find a copy of the How to Organize a Programming Language Club Handbook. Maybe it’s sold out?  Yes, Stack Overflow has quite a bit of information on how to learn and teach new languages and there’s also a good number of online tutorials which provide language introductions but I was interested in group learning.  After   two months of meetings, I present to you the Unofficial How to Organize a Programming Language Club Handbook.  1. Gauge interest. Start by surveying prospects. “Excuse me, smart-developer-whom-I-work-with-and-I-think-might-be-interested-in-learning-a-new-coding-language-with-me. Are you interested in learning a new language with me?” If you’re lucky, you work with a bunch of really smart folks who aren’t shy about teaching/learning in a group setting and you’ll have a collective interest in no time.  Simply suggesting the idea is the only effort required.  If you don’t work in this type of environment, maybe you should consider a new place of employment.  2. Make it official. Send out a “Welcome to the Club” email: There’s been talk of folks itching to learn new languages – Python, Scala, F# and Haskell to name a few.  Rather than taking on new languages alone, let’s learn in the open.  That’s right.  Let’s start a languages club.  We’ll have everything a real club needs – secret handshake, goofy motto and a high-and-mighty sense that we’re better than everybody else. T-shirts?  Hell YES!  Anyway, I’ve thrown this idea around the office and no one has laughed at me yet so please consider this your very official invitation to be in THE club. [Insert your ideas about how the club might be run, solicit feedback and suggestions, ask what other folks would like to get out the club, comment about club hazing practices and talk up the T-shirts even more. Finally, call out the languages you are interested in learning and ask the group for their list.] 3.  Send out invitations to the first meeting.  Don’t skimp!  Hallmark greeting cards for everyone.  Personalized.  Hearts over the I’s and everything.  Oh, and be sure to include the list of suggested languages with vote count.  Here the list of languages we are interested in: Python 5 Ruby 4 Objective-C 3 F# 2 Haskell 2 Scala 2 Ada 1 Boo 1 C# 1 Clojure 1 Erlang 1 Go 1 Pi 1 Prolog 1 Qt 1 4.  At the first meeting, there must be cake.  Lots of cake. And you should tackle some very important questions: Which language should we start with?  You can immediately go with the top vote getter or you could do as we did and designate each person to provide a high-level review of each of the proposed languages over the next two weeks.  After all presentations are completed, vote on the language. Our high-level review consisted of answers to a series of questions. Decide how often and where the group will meet.  We, for example, meet for a brown bag lunch every Wednesday.  Decide how you’re going to learn.  We determined that the best way to learn is to just dive in and write code.  After choosing our first language (Python), we talked about building an application, or performing coding katas, but we ultimately choose to complete a series of Project Euler problems.  We kept it simple – each member works out the same two problems each week in preparation of a code review the following Wednesday. 5.  Code, Review, Learn.  Prior to the weekly meeting, everyone uploads their solutions to our internal wiki.  Each Project Euler problem has a dedicated page.  In the meeting, we use a really fancy HD projector to show off each member’s solution.  It is very important to use an HD projector.  Again, don’t skimp!  Each code author speaks to their solution, everyone else comments, applauds, points fingers and laughs, etc.  As much as I’ve learned from solving the problems on my own, I’ve learned at least twice as much at the group code review.  6.  Rinse. Lather. Repeat.  We’ve hosted the language club for 7 weeks now.  The first meeting just set the stage.  The next two meetings provided a review of the languages followed by a first language selection.  The remaining meetings focused on Python and Project Euler problems.  Today we took a vote as to whether or not we’re ready to switch to another language and/or another problem set.  Pretty much everyone wants to stay the course for a few more weeks at least.  Until then, we’ll continue to code the next two solutions, review and learn. Again, we’ve been having a good time with the programming language club.  I’m glad it got off the ground.  What do you think?  Would you be interested in a language club?  Any suggestions on what we might do better?

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  • Asserting with JustMock

    - by mehfuzh
    In this post, i will be digging in a bit deep on Mock.Assert. This is the continuation from previous post and covers up the ways you can use assert for your mock expectations. I have used another traditional sample of Talisker that has a warehouse [Collaborator] and an order class [SUT] that will call upon the warehouse to see the stock and fill it up with items. Our sample, interface of warehouse and order looks similar to : public interface IWarehouse {     bool HasInventory(string productName, int quantity);     void Remove(string productName, int quantity); }   public class Order {     public string ProductName { get; private set; }     public int Quantity { get; private set; }     public bool IsFilled { get; private set; }       public Order(string productName, int quantity)     {         this.ProductName = productName;         this.Quantity = quantity;     }       public void Fill(IWarehouse warehouse)     {         if (warehouse.HasInventory(ProductName, Quantity))         {             warehouse.Remove(ProductName, Quantity);             IsFilled = true;         }     }   }   Our first example deals with mock object assertion [my take] / assert all scenario. This will only act on the setups that has this “MustBeCalled” flag associated. To be more specific , let first consider the following test code:    var order = new Order(TALISKER, 0);    var wareHouse = Mock.Create<IWarehouse>();      Mock.Arrange(() => wareHouse.HasInventory(Arg.Any<string>(), 0)).Returns(true).MustBeCalled();    Mock.Arrange(() => wareHouse.Remove(Arg.Any<string>(), 0)).Throws(new InvalidOperationException()).MustBeCalled();    Mock.Arrange(() => wareHouse.Remove(Arg.Any<string>(), 100)).Throws(new InvalidOperationException());      //exercise    Assert.Throws<InvalidOperationException>(() => order.Fill(wareHouse));    // it will assert first and second setup.    Mock.Assert(wareHouse); Here, we have created the order object, created the mock of IWarehouse , then I setup our HasInventory and Remove calls of IWarehouse with my expected, which is called by the order.Fill internally. Now both of these setups are marked as “MustBeCalled”. There is one additional IWarehouse.Remove that is invalid and is not marked.   On line 9 ,  as we do order.Fill , the first and second setups will be invoked internally where the third one is left  un-invoked. Here, Mock.Assert will pass successfully as  both of the required ones are called as expected. But, if we marked the third one as must then it would fail with an  proper exception. Here, we can also see that I have used the same call for two different setups, this feature is called sequential mocking and will be covered later on. Moving forward, let’s say, we don’t want this must call, when we want to do it specifically with lamda. For that let’s consider the following code: //setup - data var order = new Order(TALISKER, 50); var wareHouse = Mock.Create<IWarehouse>();   Mock.Arrange(() => wareHouse.HasInventory(TALISKER, 50)).Returns(true);   //exercise order.Fill(wareHouse);   //verify state Assert.True(order.IsFilled); //verify interaction Mock.Assert(()=> wareHouse.HasInventory(TALISKER, 50));   Here, the snippet shows a case for successful order, i haven’t used “MustBeCalled” rather i used lamda specifically to assert the call that I have made, which is more justified for the cases where we exactly know the user code will behave. But, here goes a question that how we are going assert a mock call if we don’t know what item a user code may request for. In that case, we can combine the matchers with our assert calls like we do it for arrange: //setup - data  var order = new Order(TALISKER, 50);  var wareHouse = Mock.Create<IWarehouse>();    Mock.Arrange(() => wareHouse.HasInventory(TALISKER, Arg.Matches<int>( x => x <= 50))).Returns(true);    //exercise  order.Fill(wareHouse);    //verify state  Assert.True(order.IsFilled);    //verify interaction  Mock.Assert(() => wareHouse.HasInventory(Arg.Any<string>(), Arg.Matches<int>(x => x <= 50)));   Here, i have asserted a mock call for which i don’t know the item name,  but i know that number of items that user will request is less than 50.  This kind of expression based assertion is now possible with JustMock. We can extent this sample for properties as well, which will be covered shortly [in other posts]. In addition to just simple assertion, we can also use filters to limit to times a call has occurred or if ever occurred. Like for the first test code, we have one setup that is never invoked. For such, it is always valid to use the following assert call: Mock.Assert(() => wareHouse.Remove(Arg.Any<string>(), 100), Occurs.Never()); Or ,for warehouse.HasInventory we can do the following: Mock.Assert(() => wareHouse.HasInventory(Arg.Any<string>(), 0), Occurs.Once()); Or,  to be more specific, it’s even better with: Mock.Assert(() => wareHouse.HasInventory(Arg.Any<string>(), 0), Occurs.Exactly(1));   There are other filters  that you can apply here using AtMost, AtLeast and AtLeastOnce but I left those to the readers. You can try the above sample that is provided in the examples shipped with JustMock.Please, do check it out and feel free to ping me for any issues.   Enjoy!!

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  • Robotic Arm &ndash; Hardware

    - by Szymon Kobalczyk
    This is first in series of articles about project I've been building  in my spare time since last Summer. Actually it all began when I was researching a topic of modeling human motion kinematics in order to create gesture recognition library for Kinect. This ties heavily into motion theory of robotic manipulators so I also glanced at some designs of robotic arms. Somehow I stumbled upon this cool looking open source robotic arm: It was featured on Thingiverse and published by user jjshortcut (Jan-Jaap). Since for some time I got hooked on toying with microcontrollers, robots and other electronics, I decided to give it a try and build it myself. In this post I will describe the hardware build of the arm and in later posts I will be writing about the software to control it. Another reason to build the arm myself was the cost factor. Even small commercial robotic arms are quite expensive – products from Lynxmotion and Dagu look great but both cost around USD $300 (actually there is one cheap arm available but it looks more like a toy to me). In comparison this design is quite cheap. It uses seven hobby grade servos and even the cheapest ones should work fine. The structure is build from a set of laser cut parts connected with few metal spacers (15mm and 47mm) and lots of M3 screws. Other than that you’d only need a microcontroller board to drive the servos. So in total it comes a lot cheaper to build it yourself than buy an of the shelf robotic arm. Oh, and if you don’t like this one there are few more robotic arm projects at Thingiverse (including one by oomlout). Laser cut parts Some time ago I’ve build another robot using laser cut parts so I knew the process already. You can grab the design files in both DXF and EPS format from Thingiverse, and there are also 3D models of each part in STL. Actually the design is split into a second project for the mini servo gripper (there is also a standard servo version available but it won’t fit this arm).  I wanted to make some small adjustments, layout, and add measurements to the parts before sending it for cutting. I’ve looked at some free 2D CAD programs, and finally did all this work using QCad 3 Beta with worked great for me (I also tried LibreCAD but it didn’t work that well). All parts are cut from 4 mm thick material. Because I was worried that acrylic is too fragile and might break, I also ordered another set cut from plywood. In the end I build it from plywood because it was easier to glue (I was told acrylic requires a special glue). Btw. I found a great laser cutter service in Kraków and highly recommend it (www.ebbox.com.pl). It cost me only USD $26 for both sets ($16 acrylic + $10 plywood). Metal parts I bought all the M3 screws and nuts at local hardware store. Make sure to look for nylon lock (nyloc) nuts for the gripper because otherwise it unscrews and comes apart quickly. I couldn’t find local store with metal spacers and had to order them online (you’d need 11 x 47mm and 3 x 15mm). I think I paid less than USD $10 for all metal parts. Servos This arm uses five standards size servos to drive the arm itself, and two micro servos are used on the gripper. Author of the project used Modelcraft RS-2 Servo and Modelcraft ES-05 HT Servo. I had two Futaba S3001 servos laying around, and ordered additional TowerPro SG-5010 standard size servos and TowerPro SG90 micro servos. However it turned out that the SG90 won’t fit in the gripper so I had to replace it with a slightly smaller E-Sky EK2-0508 micro servo. Later it also turned out that Futaba servos make some strange noise while working so I swapped one with TowerPro SG-5010 which has higher torque (8kg / cm). I’ve also bought three servo extension cables. All servos cost me USD $45. Assembly The build process is not difficult but you need to think carefully about order of assembling it. You can do the base and upper arm first. Because two servos in the base are close together you need to put first with one piece of lower arm already connected before you put the second servo. Then you connect the upper arm and finally put the second piece of lower arm to hold it together. Gripper and base require some gluing so think it through too. Make sure to look closely at all the photos on Thingiverse (also other people copies) and read additional posts on jjshortcust’s blog: My mini servo grippers and completed robotic arm  Multiply the robotic arm and electronics Here is also Rob’s copy cut from aluminum My assembled arm looks like this – I think it turned out really nice: Servo controller board The last piece of hardware I needed was an electronic board that would take command from PC and drive all seven servos. I could probably use Arduino for this task, and in fact there are several Arduino servo shields available (for example from Adafruit or Renbotics).  However one problem is that most support only up to six servos, and second that their accuracy is limited by Arduino’s timer frequency. So instead I looked for dedicated servo controller and found a series of Maestro boards from Pololu. I picked the Pololu Mini Maestro 12-Channel USB Servo Controller. It has many nice features including native USB connection, high resolution pulses (0.25µs) with no jitter, built-in speed and acceleration control, and even scripting capability. Another cool feature is that besides servo control, each channel can be configured as either general input or output. So far I’m using seven channels so I still have five available to connect some sensors (for example distance sensor mounted on gripper might be useful). And last but important factor was that they have SDK in .NET – what more I could wish for! The board itself is very small – half of the size of Tic-Tac box. I picked one for about USD $35 in this store. Perhaps another good alternative would be the Phidgets Advanced Servo 8-Motor – but it is significantly more expensive at USD $87.30. The Maestro Controller Driver and Software package includes Maestro Control Center program with lets you immediately configure the board. For each servo I first figured out their move range and set the min/max limits. I played with setting the speed an acceleration values as well. Big issue for me was that there are two servos that control position of lower arm (shoulder joint), and both have to be moved at the same time. This is where the scripting feature of Pololu board turned out very helpful. I wrote a script that synchronizes position of second servo with first one – so now I only need to move one servo and other will follow automatically. This turned out tricky because I couldn’t find simple offset mapping of the move range for each servo – I had to divide it into several sub-ranges and map each individually. The scripting language is bit assembler-like but gets the job done. And there is even a runtime debugging and stack view available. Altogether I’m very happy with the Pololu Mini Maestro Servo Controller, and with this final piece I completed the build and was able to move my arm from the Meastro Control program.   The total cost of my robotic arm was: $10 laser cut parts $10 metal parts $45 servos $35 servo controller ----------------------- $100 total So here you have all the information about the hardware. In next post I’ll start talking about the software that I wrote in Microsoft Robotics Developer Studio 4. Stay tuned!

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