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• Normalizing Item Names & Synonyms

  - by RabidFire

  Consider an e-commerce application with multiple stores. Each store owner can edit the item catalog of his store. My current database schema is as follows: item_names: id | name | description | picture | common(BOOL) items: id | item_name_id | picture | price | description | picture item_synonyms: id | item_name_id | name | error(BOOL) Notes: error indicates a wrong spelling (eg. "Ericson"). description and picture of the item_names table are "globals" that can optionally be overridden by "local" description and picture fields of the items table (in case the store owner wants to supply a different picture for an item). common helps separate unique item names ("Jimmy Joe's Cheese Pizza" from "Cheese Pizza") I think the bright side of this schema is: Optimized searching & Handling Synonyms: I can query the item_names & item_synonyms tables using name LIKE %QUERY% and obtain the list of item_name_ids that need to be joined with the items table. (Examples of synonyms: "Sony Ericsson", "Sony Ericson", "X10", "X 10") Autocompletion: Again, a simple query to the item_names table. I can avoid the usage of DISTINCT and it minimizes number of variations ("Sony Ericsson Xperia™ X10", "Sony Ericsson - Xperia X10", "Xperia X10, Sony Ericsson") The down side would be: Overhead: When inserting an item, I query item_names to see if this name already exists. If not, I create a new entry. When deleting an item, I count the number of entries with the same name. If this is the only item with that name, I delete the entry from the item_names table (just to keep things clean; accounts for possible erroneous submissions). And updating is the combination of both. Weird Item Names: Store owners sometimes use sentences like "Harry Potter 1, 2 Books + CDs + Magic Hat". There's something off about having so much overhead to accommodate cases like this. This would perhaps be the prime reason I'm tempted to go for a schema like this: items: id | name | picture | price | description | picture (... with item_names and item_synonyms as utility tables that I could query) Is there a better schema you would suggested? Should item names be normalized for autocomplete? Is this probably what Facebook does for "School", "City" entries? Is the first schema or the second better/optimal for search? Thanks in advance! References: (1) Is normalizing a person's name going too far?, (2) Avoiding DISTINCT

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• How do I classify using SVM Classifier?

  - by Gomathi

  I'm doing a project in liver tumor classification. Actually I initially used Region Growing method for liver segmentation and from that I segmented tumor using FCM. I,then, obtained the texture features using Gray Level Co-occurence Matrix. My output for that was stats = autoc: [1.857855266614132e+000 1.857955341199538e+000] contr: [5.103143332457753e-002 5.030548650257343e-002] corrm: [9.512661919561399e-001 9.519459060378332e-001] corrp: [9.512661919561385e-001 9.519459060378338e-001] cprom: [7.885631654779597e+001 7.905268525471267e+001] Now how should I give this as an input to the SVM program. function [itr] = multisvm( T,C,tst ) %MULTISVM(2.0) classifies the class of given training vector according to the % given group and gives us result that which class it belongs. % We have also to input the testing matrix %Inputs: T=Training Matrix, C=Group, tst=Testing matrix %Outputs: itr=Resultant class(Group,USE ROW VECTOR MATRIX) to which tst set belongs %----------------------------------------------------------------------% % IMPORTANT: DON'T USE THIS PROGRAM FOR CLASS LESS THAN 3, % % OTHERWISE USE svmtrain,svmclassify DIRECTLY or % % add an else condition also for that case in this program. % % Modify required data to use Kernel Functions and Plot also% %----------------------------------------------------------------------% % Date:11-08-2011(DD-MM-YYYY) % % This function for multiclass Support Vector Machine is written by % ANAND MISHRA (Machine Vision Lab. CEERI, Pilani, India) % and this is free to use. email: [email protected] % Updated version 2.0 Date:14-10-2011(DD-MM-YYYY) u=unique(C); N=length(u); c4=[]; c3=[]; j=1; k=1; if(N>2) itr=1; classes=0; cond=max(C)-min(C); while((classes~=1)&&(itr<=length(u))&& size(C,2)>1 && cond>0) %This while loop is the multiclass SVM Trick c1=(C==u(itr)); newClass=c1; svmStruct = svmtrain(T,newClass); classes = svmclassify(svmStruct,tst); % This is the loop for Reduction of Training Set for i=1:size(newClass,2) if newClass(1,i)==0; c3(k,:)=T(i,:); k=k+1; end end T=c3; c3=[]; k=1; % This is the loop for reduction of group for i=1:size(newClass,2) if newClass(1,i)==0; c4(1,j)=C(1,i); j=j+1; end end C=c4; c4=[]; j=1; cond=max(C)-min(C); % Condition for avoiding group %to contain similar type of values %and the reduce them to process % This condition can select the particular value of iteration % base on classes if classes~=1 itr=itr+1; end end end end Kindly guide me. Images:

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• for loop with count from array, limit output? PHP

  - by Philip

  print '<div id="wrap">'; print "<table width=\"100%\" border=\"0\" align=\"center\" cellpadding=\"3\" cellspacing=\"3\">"; for($i=0; $i<count($news_comments); $i++) { print ' <tr> <td width="30%"><strong>'.$news_comments[$i]['comment_by'].'</strong></td> <td width="70%">'.$news_comments[$i]['comment_date'].'</td> </tr> <tr> <td></td> <td>'.$news_comments[$i]['comment'].'</td> </tr> '; } print '</table></div>'; $news_comments is a 3 diemensional array from mysqli_fetch_assoc returned from a function elsewhere, for some reason my for loop returns the total of the array sets such as [0][2] etc until it reaches the max amount from the counted $news_comments var which is a return function of LIMIT 10. my problem is if I add any text/html/icons inside the for loop it prints it in this case 11 times even though only array sets 1 and 2 have data inside them. How do I get around this? My function query is as follows: function news_comments() { require_once '../data/queries.php'; // get newsID from the url $urlID = $_GET['news_id']; // run our query for newsID information $news_comments = selectQuery('*', 'news_comments', 'WHERE news_id='.$urlID.'', 'ORDER BY comment_date', 'DESC', '10'); // requires 6 params // check query for results if(!$news_comments) { // loop error session and initiate var foreach($_SESSION['errors'] as $error=>$err) { print htmlentities($err) . 'for News Comments, be the first to leave a comment!'; } } else { print '<div id="wrap">'; print "<table width=\"100%\" border=\"0\" align=\"center\" cellpadding=\"3\" cellspacing=\"3\">"; for($i=0; $i<count($news_comments); $i++) { print ' <tr> <td width="30%"><strong>'.$news_comments[$i]['comment_by'].'</strong></td> <td width="70%">'.$news_comments[$i]['comment_date'].'</td> </tr> <tr> <td></td> <td>'.$news_comments[$i]['comment'].'</td> </tr> '; } print '</table></div>'; } }// End function Any help is greatly appreciated.

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• a script translatable to JavaScript with callback-hell automatic avoider :-)

  - by m1uan

  I looking for "translator" for JavaScript like already is CoffeScript, which will be work for example with forEach (inspired by Groovy) myArray.forEach() -> val, idx { // do something with value and idx } translate to JavaScript myArray.forEach(function(val, idx){ // do something with value and idx }); or something more usefull... function event(cb){ foo()-> err, data1; bar(data1)-> err, data2; cb(data2); } the method are encapsulated function event(cb){ foo(function(err,data1){ bar(data1, function(err, data2) { cb(data2); }); }); } I want ask if similar "compiler" to JavaScript like this even better already doesn't exists? What would be super cool... my code in nodejs looks mostly like this :-) function dealer(cb){ async.parallel([ function(pcb){ async.watterfall([function(wcb){ first(function(a){ wcb(a); }); }, function(a, wcb){ thirt(a, function(c){ wcb(c); }); fourth(a, function(d){ // dealing with “a” as well and nobody care my result }); }], function(err, array_with_ac){ pcb(array_with_ac); }); }, function(pcb){ second(function(b){ pcb(b);}); }], function(err, data){ cb(data[0][0]+data[1]+data[0][1]); // dealing with “a” “b” and “c” not with “d” }); } but, look how beautiful and readable the code could be: function dealer(cb){ first() -> a; second() -> b; third(a) -> c; // dealing with “a” fourth(a) -> d; // dealing with “a” as well and nobody care about my result cb(a+b+c); // dealing with “a” “b” and “c” not with “d” } yes this is ideal case when the translator auto-decide, method need to be run as parallel and method need be call after finish another method. I can imagine it's works Please, do you know about something similar? Thank you for any advice;-)

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• Memory corruption in System.Move due to changed 8087CW mode (png + stretchblt)

  - by André Mussche

  I have strange a memory corruption problem. After many hours debugging and trying I think I found something. For example: I do a simple string assignment: sTest := 'SET LOCK_TIMEOUT '; However, the result sometimes becomes: sTest = 'SET LOCK'#0'TIMEOUT ' So, the _ gets replaced by an 0 byte. I have seen this happening once (reproducing is tricky, dependent on timing) in the System.Move function, when it uses the FPU stack (fild, fistp) for fast memory copy (in case of 9 till 32 bytes to move): ... @@SmallMove: {9..32 Byte Move} fild qword ptr [eax+ecx] {Load Last 8} fild qword ptr [eax] {Load First 8} cmp ecx, 8 jle @@Small16 fild qword ptr [eax+8] {Load Second 8} cmp ecx, 16 jle @@Small24 fild qword ptr [eax+16] {Load Third 8} fistp qword ptr [edx+16] {Save Third 8} ... Using the FPU view and 2 memory debug views (Delphi - View - Debug - CPU - Memory) I saw it going wrong... once... could not reproduce however... This morning I read something about the 8087CW mode, and yes, if this is changed into $27F I get memory corruption! Normally it is $133F: The difference between $133F and $027F is that $027F sets up the FPU for doing less precise calculations (limiting to Double in stead of Extended) and different infiniti handling (which was used for older FPU’s, but is not used any more). Okay, now I found why but not when! I changed the working of my AsmProfiler with a simple check (so all functions are checked at enter and leave): if Get8087CW = $27F then //normally $1372? if MainThreadID = GetCurrentThreadId then //only check mainthread DebugBreak; I "profiled" some units and dll's and bingo (see stack): Windows.StretchBlt(3372289943,0,0,514,345,4211154027,0,0,514,345,13369376) pngimage.TPNGObject.DrawPartialTrans(4211154027,(0, 0, 514, 345, (0, 0), (514, 345))) pngimage.TPNGObject.Draw($7FF62450,(0, 0, 514, 345, (0, 0), (514, 345))) Graphics.TCanvas.StretchDraw((0, 0, 514, 345, (0, 0), (514, 345)),$7FECF3D0) ExtCtrls.TImage.Paint Controls.TGraphicControl.WMPaint((15, 4211154027, 0, 0)) So it is happening in StretchBlt... What to do now? Is it a fault of Windows, or a bug in PNG (included in D2007)? Or is the System.Move function not failsafe?

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• C# Property Access vs Interface Implementation

  - by ehdv

  I'm writing a class to represent a Pivot Collection, the root object recognized by Pivot. A Collection has several attributes, a list of facet categories (each represented by a FacetCategory object) and a list of items (each represented by a PivotItem object). Therefore, an extremely simplified Collection reads: public class Collection { private List<FacetCategory> categories; private List<PivotItem> items; // other attributes } What I'm unsure of is how to properly grant access to those two lists. Because declaration order of both facet categories and items is visible to the user, I can't use sets, but the class also shouldn't allow duplicate categories or items. Furthermore, I'd like to make the Collection object as easy to use as possible. So my choices are: Have Collection implement IList<PivotItem> and have accessor methods for FacetCategory: In this case, one would add an item to Collection foo by writing foo.Add(bar). This works, but since a Collection is equally both kinds of list making it only pass as a list for one type (category or item) seems like a subpar solution. Create nested wrapper classes for List (CategoryList and ItemList). This has the advantage of making a consistent interface but the downside is that these properties would no longer be able to serve as lists (because I need to override the non-virtual Add method I have to implement IList rather than subclass List. Implicit casting wouldn't work because that would return the Add method to its normal behavior. Also, for reasons I can't figure out, IList is missing an AddRange method... public class Collection { private class CategoryList: IList<FacetCategory> { // ... } private readonly CategoryList categories = new CategoryList(); private readonly ItemList items = new ItemList(); public CategoryList FacetCategories { get { return categories; } set { categories.Clear(); categories.AddRange(value); } } public ItemList Items { get { return items; } set { items.Clear(); items.AddRange(value); } } } Finally, the third option is to combine options one and two, so that Collection implements IList<PivotItem> and has a property FacetCategories. Question: Which of these three is most appropriate, and why?

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• Bad_alloc exception when using new for a struct c++

  - by bsg

  Hi, I am writing a query processor which allocates large amounts of memory and tries to find matching documents. Whenever I find a match, I create a structure to hold two variables describing the document and add it to a priority queue. Since there is no way of knowing how many times I will do this, I tried creating my structs dynamically using new. When I pop a struct off the priority queue, the queue (STL priority queue implementation) is supposed to call the object's destructor. My struct code has no destructor, so I assume a default destructor is called in that case. However, the very first time that I try to create a DOC struct, I get the following error: Unhandled exception at 0x7c812afb in QueryProcessor.exe: Microsoft C++ exception: std::bad_alloc at memory location 0x0012f5dc.. I don't understand what's happening - have I used up so much memory that the heap is full? It doesn't seem likely. And it's not as if I've even used that pointer before. So: first of all, what am I doing that's causing the error, and secondly, will the following code work more than once? Do I need to have a separate pointer for each struct created, or can I re-use the same temporary pointer and assume that the queue will keep a pointer to each struct? Here is my code: struct DOC{ int docid; double rank; public: DOC() { docid = 0; rank = 0.0; } DOC(int num, double ranking) { docid = num; rank = ranking; } bool operator>( const DOC & d ) const { return rank > d.rank; } bool operator<( const DOC & d ) const { return rank < d.rank; } }; //a lot of processing goes on here; when a matching document is found, I do this: rank = calculateRanking(table, num); //if the heap is not full, create a DOC struct with the docid and rank and add it to the heap if(q.size() < 20) { doc = new DOC(num, rank); q.push(*doc); doc = NULL; } //if the heap is full, but the new rank is greater than the //smallest element in the min heap, remove the current smallest element //and add the new one to the heap else if(rank > q.top().rank) { q.pop(); cout << "pushing doc on to queue" << endl; doc = new DOC(num, rank); q.push(*doc); } Thank you very much, bsg.

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• Removing elements from heap

  - by user193138

  I made a heap. I am curious if there's something subtley wrong with my remove function: int Heap::remove() { if (n == 0) exit(1); int temp = arr[0]; arr[0] = arr[--n]; heapDown(0); arr[n] = 0; return temp; } void Heap::heapDown(int i) { int l = left(i); int r = right(i); // comparing parent to left/right child // each has an inner if to handle if the first swap causes a second swap // ie 1 -> 3 -> 5 // 3 5 1 5 1 3 if (l < n && arr[i] < arr[l]) { swap(arr[i], arr[l]); heapDown(l); if (r < n && arr[i] < arr[r]) { swap(arr[i], arr[r]); heapDown(r); } } else if (r < n && arr[i] < arr[r]) { swap(arr[i], arr[r]); heapDown(r); if (l < n && arr[i] < arr[l]) { swap(arr[i], arr[l]); heapDown(l); } } } Here's my output i1i2i3i4i5i6i7 p Active heap: 7 4 6 1 3 2 5 r Removed 7 r Removed 6 p Active heap: 5 3 4 1 2 Here's my teacher's sample output: p Active heap : 7 4 6 1 3 2 5 r Removed 7 r Removed 6 p Active heap : 5 4 2 1 3 s Heapsorted : 1 2 3 4 5 While our outputs are completely different, I do seem to hold maxheap principle of having everything left oriented and for all nodes parent child(in every case I tried). I try to do algs like this from scratch, so maybe I'm just doing something really weird and wrong (I would only consider it "wrong" if it's O(lg n), as removes are intended to be for heaps). Is there anything in particular "wrong" about my remove? Thanks, http://ideone.com/PPh4eQ

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• Uploading file to DropBox causing UnlinkedException

  - by Boardy

  I am currently working on android project and trying to enable DropBox functionality. I've selected the access type to App Only, and I can successfully authenticate and it creates an Apps directory and inside that creates a directory with the name of my app. When I then try to put a file in the DropBox directory it goes into the DropBoxException catch and in the logcat prints com.dropbox.client2.exception.DropboxUnlinkedException. I've done a google and from what I've seen this happens if the apps directory has been deleted and so authentication is required to be re-done, but this isn't the case, I have deleted it and I am putting the file straight after doing the authentication. Below is the code that retrieves the keys and stores the file on dropbox. AccessTokenPair tokens = getTokens(); UploadFile uploadFile = new UploadFile(context, common, this, mDBApi); uploadFile.execute(mDBApi); Below is the code for the getTokens method (don't think this would help but you never know) private AccessTokenPair getTokens() { AccessTokenPair tokens; SharedPreferences prefs = context.getSharedPreferences("prefs", 0); String key = prefs.getString("dropbox_key", ""); String secret = prefs.getString("dropbox_secret", ""); tokens = new AccessTokenPair(key, secret); return tokens; } Below is the class that extends the AsyncTask to perform the upload class UploadFile extends AsyncTask<DropboxAPI<AndroidAuthSession>, Void, bool> { Context context; Common common; Synchronisation sync; DropboxAPI<AndroidAuthSession> mDBApi; public UploadFile(Context context, Common common, Synchronisation sync, DropboxAPI<AndroidAuthSession> mDBApi) { this.context = context; this.common = common; this.sync = sync; this.mDBApi = mDBApi; } @Override protected bool doInBackground(DropboxAPI<AndroidAuthSession>... params) { try { File file = new File(Environment.getExternalStorageDirectory() + "/BoardiesPasswordManager/dropbox_sync.xml"); FileInputStream inputStream = new FileInputStream(file); Entry newEntry = mDBApi.putFile("android_sync.xml", inputStream, file.length(), null, null); common.showToastMessage("Successfully uploade Rev: " + newEntry.rev, Toast.LENGTH_LONG); } catch (IOException ex) { Log.e("DropBoxError", ex.toString()); } catch (DropboxException e) { Log.e("DropBoxError", e.toString()); e.printStackTrace(); } return null; } I have no idea why it would display the UnlinkedException so any help would be greatly appreciated.

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• How to update NSMutableDictionary. My code doesn't work.

  - by dawatson833

  I've populated an array using. arrSettings = [[NSMutableArray alloc] initWithContentsOfFile:[self settingsPath]]; The file is a plist with the root as an array and then a dictionary with three three keys defined as number. I've also tried setting the keys to string. I display the values in the plist file on a view using. diaper = [[arrSettings objectAtIndex:0] objectForKey:@"Diaper Expenses"]; oil = [[arrSettings objectAtIndex:0] objectForKey:@"Oil Used"]; tree = [[arrSettings objectAtIndex:0] objectForKey:@"Wood Used"]; This code works fine, the values in the dictionary are assigned to the variables and they are displayed. The user can make changes and then press a save button. I use this code to extract the dictionary part of the array so I can update it. The assignment to editDictionary works. I've double checked the key names including case and that is correct. editDictionary = [[NSMutableDictionary alloc] init]; editDictionary = [arrSettings objectAtIndex:0]; NSNumber *myNumber = [NSNumber numberWithFloat:diaperAmount]; [editDictionary setValue:myNumber forKey:@"Diaper Expenses"]; myNumber = [NSNumber numberWithFloat:oilAmount]; [editDictionary setValue:myNumber forKey:@"Oil Used"]; myNumber = [NSNumber numberWithFloat:treeAmount]; [editDictionary setValue:myNumber forKey:@"Wood Used"]; In this example I've used a nsnumber. But I've also tried the xxxAmount field as part of SetValue instead of creating a NSNumber. Neither implementation works. Several strange things happen. Sometimes the first two setvalue statements work, but the last setvalue fails with a EXC_BAD_ACCESS failure. Other times the first setValue fails with the same error. I have no idea why the first two sometimes work. I'm at a loss of what to do next. I've tried several implentations and none of them work. Also, in the debugger how can I display the editDictionary elements. I can see editDictionary, but I don't know how to display the individual elements.

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• .NET: Is there a way to finagle a default namespace in an XPath 1.0 query?

  - by Cheeso

  I'm building a tool that performs xpath 1.0 queries on XHTML documents. The requirement to use a namespace prefix in the query is killing me. The query looks like this: html/body/div[@class='contents']/div[@class='body']/ div[@class='pgdbbyauthor']/h2[a[@name][starts-with(.,'Quick')]]/ following-sibling::ul[1]/li/a (all on one line) ...which is bad enough, except because it's xpath 1.0, I need to use an explicit namespace prefix on each QName, so it looks like this: ns1:html/ns1:body/ns1:div[@class='contents']/ns1:div[@class='body']/ ns1:div[@class='pgdbbyauthor']/ns1:h2[ns1:a[@name][starts-with(.,'Quick')]]/ following-sibling::ns1:ul[1]/ns1:li/ns1:a To set up the query, I do something like this: var xpathDoc = new XPathDocument(new StringReader(theText)); var nav = xpathDoc.CreateNavigator(); var xmlns = new XmlNamespaceManager(nav.NameTable); foreach (string prefix in xmlNamespaces.Keys) xmlns.AddNamespace(prefix, xmlNamespaces[prefix]); XPathNodeIterator selection = nav.Select(xpathExpression, xmlns); But what I want is for the xpathExpression to use the implicit default namespace. Is there a way for me to transform the unadorned xpath expression, after it's been written, to inject a namespace prefix for each element name in the query? I'm thinking, anything between two slashes, I could inject a prefix there. Excepting of course axis names like "parent::" and "preceding-sibling::" . And wildcards. That's what I mean by "finagle a default namespace". Is this hack gonna work? Addendum Here's what I mean. suppose I have an xpath expression, and before passing it to nav.Select(), I transform it. Something like this: string FixupWithDefaultNamespace(string expr) { string s = expr; s = Regex.Replace(s, "^(?!::)([^/:]+)(?=/)", "ns1:$1"); // beginning s = Regex.Replace(s, "/([^/:]+)(?=/)", "/ns1:$1"); // stanza s = Regex.Replace(s, "::([A-Za-z][^/:*]*)(?=/)", "::ns1:$1"); // axis specifier s = Regex.Replace(s, "\\[([A-Za-z][^/:*\\(]*)(?=[\\[\\]])", "[ns1:$1"); // predicate s = Regex.Replace(s, "/([A-Za-z][^/:]*)(?!<::)$", "/ns1:$1"); // end s = Regex.Replace(s, "^([A-Za-z][^/:]*)$", "ns1:$1"); // edge case s = Regex.Replace(s, "([-A-Za-z]+)\\(([^/:\\.,\\)]+)(?=[,\\)])", "$1(ns1:$2"); // xpath functions return s; } This actually works for simple cases I tried. To use the example from above - if the input is the first xpath expression, the output I get is the 2nd one, with all the ns1 prefixes. The real question is, is it hopeless to expect this Regex.Replace approach to work, as the xpath expressions get more complicated?

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• Calling a function within a class

  - by JM4

  I am having trouble calling a specific function within a class. The call is made: case "Mod10": if (!validateCreditCard($fields[$field_name])) $errors[] = $error_message; break; and the class code is: class CreditCardValidationSolution { var $CCVSNumber = ''; var $CCVSNumberLeft = ''; var $CCVSNumberRight = ''; var $CCVSType = ''; var $CCVSError = ''; function validateCreditCard($Number) { $this->CCVSNumber = ''; $this->CCVSNumberLeft = ''; $this->CCVSNumberRight = ''; $this->CCVSType = ''; $this->CCVSError = ''; // Catch malformed input. if (empty($Number) || !is_string($Number)) { $this->CCVSError = $CCVSErrNumberString; return FALSE; } // Ensure number doesn't overrun. $Number = substr($Number, 0, 20); // Remove non-numeric characters. $this->CCVSNumber = preg_replace('/[^0-9]/', '', $Number); // Set up variables. $this->CCVSNumberLeft = substr($this->CCVSNumber, 0, 4); $this->CCVSNumberRight = substr($this->CCVSNumber, -4); $NumberLength = strlen($this->CCVSNumber); $DoChecksum = 'Y'; // Mod10 checksum process... if ($DoChecksum == 'Y') { $Checksum = 0; // Add even digits in even length strings or odd digits in odd length strings. for ($Location = 1 - ($NumberLength % 2); $Location < $NumberLength; $Location += 2) { $Checksum += substr($this->CCVSNumber, $Location, 1); } // Analyze odd digits in even length strings or even digits in odd length strings. for ($Location = ($NumberLength % 2); $Location < $NumberLength; $Location += 2) { $Digit = substr($this->CCVSNumber, $Location, 1) * 2; if ($Digit < 10) { $Checksum += $Digit; } else { $Checksum += $Digit - 9; } } // Checksums not divisible by 10 are bad. if ($Checksum % 10 != 0) { $this->CCVSError = $CCVSErrChecksum; return FALSE; } } return TRUE; } } When I run the application - I get the following message: Fatal error: Call to undefined function validateCreditCard() in C:\xampp\htdocs\validation.php on line 339 any ideas?

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• HLSL tex2d sampler seemingly using inconsistent rounding; why?

  - by RJFalconer

  Hello all, I have code that needs to render regions of my object differently depending on their location. I am trying to use a colour map to define these regions. The problem is when I sample from my colour map, I get collisions. Ie, two regions with different colours in the colourmap get the same value returned from the sampler. I've tried various formats of my colour map. I set the colours for each region to be "5" apart in each case; Indexed colour RGB, RGBA: region 1 will have RGB 5%,5%,5%. region 2 will have RGB 10%,10%,10% and so on. HSV Greyscale: region 1 will have HSV 0,0,5%. region 2 will have HSV 0,0,10% and so on. (Values selected in The Gimp) The tex2D sampler returns a value [0..1]. [ I then intend to derive an int array index from region. Code to do with that is unrelated, so has been removed from the question ] float region = tex2D(gColourmapSampler,In.UV).x; Sampling the "5%" colour gave a "region" of 0.05098 in hlsl. From this I assume the 5% represents 5/100*255, or 12.75, which is rounded to 13 when stored in the texture OR when sampled by the sampler; can't tell which. (Reasoning: 0.05098 * 255 ~= 13) By this logic, the 50% should be stored as 127.5. Sampled, I get 0.50196 which implies it was stored as 128. the 70% should be stored as 178.5. Sampled, I get 0.698039, which implies it was stored as 178. What rounding is going on here? (127.5 becomes 128, 178.5 becomes 178 ?!) Edit: OK, http://en.wikipedia.org/wiki/Bankers_rounding#Round_half_to_even Apparently this is "banker's rounding". Is this really what HLSL samplers use? I am using Shader Model 2 and FX Composer. This is my sampler declaration; //Colour map texture gColourmapTexture < string ResourceName = "Globe_Colourmap_Regions_Greyscale.png"; string ResourceType = "2D"; >; sampler2D gColourmapSampler : register(s1) = sampler_state { Texture = <gColourmapTexture>; #if DIRECT3D_VERSION >= 0xa00 Filter = MIN_MAG_MIP_LINEAR; #else /* DIRECT3D_VERSION < 0xa00 */ MinFilter = Linear; MipFilter = Linear; MagFilter = Linear; #endif /* DIRECT3D_VERSION */ AddressU = Clamp; AddressV = Clamp; };

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• Nested Transaction issues within custom Windows Service

  - by pdwetz

  I have a custom Windows Service I recently upgraded to use TransactionScope for nested transactions. It worked fine locally on my old dev machine (XP sp3) and on a test server (Server 2003). However, it fails on my new Windows 7 machine as well as on 2008 Server. It was targeting 2.0 framework; I tried targeting 3.5 instead, but it still fails. The strange part is really in how it fails; no exception is thrown. The service itself merely times out. I added tracing code, and it fails when opening the connection for Database lookup #2 below. I also enabled tracing for System.Transactions; it literally cuts out partway while writing the block for the failed connection. We ran a SQL trace, but only the first lookup shows up. I put in code traces, and it gets to the trace the line before the second lookup, but nothing after. I've had the same experience hitting two different SQL servers (both are SQL 2005 running on Server 2003). The connection string is utilizing a SQL account (not Windows integration). All connections are against the same database in this case, but given the nature of the code it is being escalated to MSDTC. Here's the basic code structure: TransactionOptions options = new TransactionOptions(); options.IsolationLevel = System.Transactions.IsolationLevel.ReadCommitted; using (TransactionScope scope = new TransactionScope(TransactionScopeOption.RequiresNew, options)) { // Database lookup #1 TransactionOptions options = new TransactionOptions(); options.IsolationLevel = Transaction.Current != null ? Transaction.Current.IsolationLevel : System.Transactions.IsolationLevel.ReadCommitted; using (TransactionScope scope = new TransactionScope(TransactionScopeOption.Required, options)) { // Database lookup #2; fails on connection.Open() // Database save (never reached) scope.Complete();<br/> } scope.Complete();<br/> } My local firewall is disabled. The service normally runs using Network Service, but I also tried my user account (same results). The short of it is that I use the same general technique widely in my web applications and haven't had any issues. I pulled out the code and ran it fine within a local Windows Form application. If anyone has any additional debugging ideas (or, even better, solutions) I'd love to hear them.

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• Translate RoR Code to Java

  - by mnml

  Hi, for some reasons I am trying to translate the following RoR view code to a Java Groovy view: <% modulo_artists = @artists.length % 3 base = @artists.length / 3 base = base.ceil case modulo_artists when 0 cols = [base, base, base] when 1 cols = [base, base + 1, base] when 2 cols = [base + 1, base, base + 1] end counter = 0 %> <% id_hash = {"0" => "url('/images/actorsbg.png');", "1" => "url('/images/musiciansbg.png');", "2" => "url('/images/artistsbg.png') no-repeat; color: #FFF;", "3" => "url('/images/fashionbg.png')"} %> <div id="artists_<%=params[:artist_cat]%>" style="background: <%= id_hash[params[:artist_cat]] %>;" > <table border="0" width="660" height="164" cellpadding="0" cellspacing="0"> <tr valign="middle"> <% 3.times do |i| %> <td width="220" align="center" style="padding-right: 15px;"> <% cols[i].times do %> <h1><a href="/artists/show/<%= @artists[counter].urlname %>" ><%= @artists[counter].name %></a></h1> <% counter = counter + 1 %> <% end %> </td> <% end %> </tr> </table> </div> This is what I got so far: #{extends 'main.html' /} %{ modulo_artists = artists.size() % 3 base = artists.size() / 3 base = Math.ceil(base) if(modulo_artists == 0) cols = [base, base, base] else if(modulo_artists == 1) cols = [base, base + 1, base] else if(modulo_artists == 2) cols = [base + 1, base, base + 1] endif counter = 0 }% <div id="artists_${artist_cat}" style="background:${id_hash};" > <table border="0" width="660" height="164" cellpadding="0" cellspacing="0"> <tr valign="middle"> #{list items:1..3, as:'i'} <td width="220" align="center" style="padding-right: 15px;"> #{list items:cols[i]} <h1><a href="@{Artists.show(artists.get(counter).name.replaceAll(" ", "-"))}" >${artists.get(counter).name}</a></h1> %{ counter = counter + 1 }% #{/list} </td> #{/list} </tr> </table> </div> The idea is to keep the items organised in 3 columns like 1|0|1 4|5|4 or 5|4|5 for example

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• Implementing Skip List in C++

  - by trikker

  [SOLVED] So I decided to try and create a sorted doubly linked skip list... I'm pretty sure I have a good grasp of how it works. When you insert x the program searches the base list for the appropriate place to put x (since it is sorted), (conceptually) flips a coin, and if the "coin" lands on a then that element is added to the list above it(or a new list is created with element in it), linked to the element below it, and the coin is flipped again, etc. If the "coin" lands on b at anytime then the insertion is over. You must also have a -infinite stored in every list as the starting point so that it isn't possible to insert a value that is less than the starting point (meaning that it could never be found.) To search for x, you start at the "top-left" (highest list lowest value) and "move right" to the next element. If the value is less than x than you continue to the next element, etc. until you have "gone too far" and the value is greater than x. In this case you go back to the last element and move down a level, continuing this chain until you either find x or x is never found. To delete x you simply search x and delete it every time it comes up in the lists. For now, I'm simply going to make a skip list that stores numbers. I don't think there is anything in the STL that can assist me, so I will need to create a class List that holds an integer value and has member functions, search, delete, and insert. The problem I'm having is dealing with links. I'm pretty sure I could create a class to handle the "horizontal" links with a pointer to the previous element and the element in front, but I'm not sure how to deal with the "vertical" links (point to corresponding element in other list?) If any of my logic is flawed please tell me, but my main questions are: How to deal with vertical links and whether my link idea is correct Now that I read my class List idea I'm thinking that a List should hold a vector of integers rather than a single integer. In fact I'm pretty positive, but would just like some validation. I'm assuming the coin flip would simply call int function where rand()%2 returns a value of 0 or 1 and if it's 0 then a the value "levels up" and if it's 0 then the insert is over. Is this incorrect? How to store a value similar to -infinite? Edit: I've started writing some code and am considering how to handle the List constructor....I'm guessing that on its construction, the "-infinite" value should be stored in the vectorname[0] element and I can just call insert on it after its creation to put the x in the appropriate place.

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• JPA entity design / cannot delete entity

  - by timaschew

  I though its simple what I want, but I cannot find any solution for my problem. I'm using playframework 1.2.3 and it's using Hibernate as JPA. So I think playframework has nothing to do with the problem. I have some classes (I omit the nonrelevant fields) public class User { ... } public class Task { public DataContainer dataContainer; } public class DataContainer { public Session session; public User user; } public class Session { ... } So I have association from Task to DataContainer and from DataContainer to Sesssion and the DataContainer belongs to a User. The DataContainers can have always the same User, but the Session have to be different for each instance. And the DataContainer of a Task have also to be different in each instance. A DataContainer can have a Sesesion or not (it's optinal). I use only unidirectional assoc. It should be sufficient. In other words: Every Task must has one DataContainer. Every DataContainer must has one/the same User and can have one Session. To create a DB schema I use JPA annotations: @Entity public class User extends Model { ... } @Entity public class Task extends Model { @OneToOne(optional = false, cascade = CascadeType.ALL) public DataContainer dataContainer; } @Entity public class DataContainer extends Model { @OneToOne(optional = true, cascade = CascadeType.ALL) public Session session; @ManyToOne(optional = false, cascade = CascadeType.ALL) public User user; } @Entity public class Session extends Model { ... } BTW: Model is a play class and provides the primary id as long type. When I create some for each entity a object and 'connect them', I mean the associations, it works fine. But when I try to delete a Session, I get a constraint violation exception, because a DataContainer still refers to the Session I want to delete. I want that the Session (field) of the DataContainer will be set to null respectively the foreign key (session_id) should be unset in the database. This will be okay, because its optional. I don't know, I think I have multiple problems. Am I using the right annotation @OneToOne ? I found on the internet some additional annotation and attributes: @JoinColumn and a mappedBy attribute for the inverse relationship. But I don't have it, because its not bidirectional. Or is a bidirectional assoc. essentially? Another try was to use @OnDelete(action = OnDeleteAction.CASCADE) the the contraint changed from NO ACTIONs when update or delete to: ADD CONSTRAINT fk4745c17e6a46a56 FOREIGN KEY (session_id) REFERENCES annotation_session (id) MATCH SIMPLE ON UPDATE NO ACTION ON DELETE CASCADE; But in this case, when I delete a session, the DataContainer and User is deleted. That's wrong for me. EDIT: I'm using postgresql 9, the jdbc stuff is included in play, my only db config is db=postgres://app:app@localhost:5432/app

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• Why does my Spring Controller direct me to the wrong page?

  - by kc2001

  I am writing my first Spring 3.0.5 MVC app and am confused about why my controller mappings aren't doing what I expect. I have a VerifyPasswordController that is called after a user tries to log in by entering his name and password. // Called upon clicking "submit" from /login @RequestMapping(value = "/verifyPassword", method = RequestMethod.POST) @ModelAttribute("user") public String verifyPassword(User user, BindingResult result) { String email = user.getEmail(); String nextPage = CHOOSE_OPERATION_PAGE; // success case if (result.hasErrors()) { nextPage = LOGIN_PAGE; } else if (!passwordMatches(email, user.getPassword())) { nextPage = LOGIN_FAILURE_PAGE; } else { // success } return nextPage; } I can verify in the debugger that this method is being called, but afterwards, the verifyPassword page is displayed rather than the chooseOperation page. The console output of WebLogic seems to show that my mapping are correct: INFO : org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping - Mapped URL path [/chooseOperation] onto handler 'chooseOperationController' INFO : org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping - Mapped URL path [/chooseOperation.*] onto handler 'chooseOperationController' INFO : org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping - Mapped URL path [/chooseOperation/] onto handler 'chooseOperationController' Here is the ChooseOperationController: @Controller @SessionAttributes("leaveRequestForm") public class ChooseOperationController implements PageIfc, AttributeIfc { @RequestMapping(value = "/chooseOperation") @ModelAttribute("leaveRequestForm") public LeaveRequest setUpLeaveRequestForm( @RequestParam(NAME_ATTRIBUTE) String name) { LeaveRequest form = populateFormFromDatabase(name); return form; } // helper methods omited } I welcome any advice, particularly "generic" techniques for debugging such mapping problems. BTW, I've also tried to "redirect" to the desired page, but got the same result. servlet-context.xml: <?xml version="1.0" encoding="UTF-8"?> <beans:beans xmlns="http://www.springframework.org/schema/mvc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:beans="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation=" http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd"> <!-- DispatcherServlet Context: defines this servlet's request-processing infrastructure --> <!-- Enables the Spring MVC @Controller programming model --> <annotation-driven /> <!-- Handles HTTP GET requests for /resources/** by efficiently serving up static resources in the ${webappRoot}/resources directory --> <resources mapping="/resources/**" location="/resources/" /> <!-- Resolves views selected for rendering by @Controllers to .jsp resources in the /WEB-INF/views directory --> <beans:bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <beans:property name="prefix" value="/WEB-INF/views/" /> <beans:property name="suffix" value=".jsp" /> </beans:bean> <context:component-scan base-package="com.engilitycorp.leavetracker" /> <beans:bean id="leaveRequestForm" class="com.engilitycorp.leavetracker.model.LeaveRequest" /> </beans:beans> The constants: String LOGIN_FAILURE_PAGE = "loginFailure"; String LOGIN_PAGE = "login"; String CHOOSE_OPERATION_PAGE = "chooseOperation";

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• Monitoring UDP socket in glib(mm) eats up CPU time

  - by Gyorgy Szekely

  Hi, I have a GTKmm Windows application (built with MinGW) that receives UDP packets (no sending). The socket is native winsock and I use glibmm IOChannel to connect it to the application main loop. The socket is read with recvfrom. My problem is: this setup eats 25% percent CPU time on a 3GHz workstation. Can somebody tell me why? The application is idle in this case, and if I remove the UDP code, CPU usage drops down to almost zero. As the application has to perform some CPU intensive tasks, I could image better ways to spend that 25% Here are some code excerpts: (sorry for the printf's ;) ) /* bind */ void UDPInterface::bindToPort(unsigned short port) { struct sockaddr_in target; WSADATA wsaData; target.sin_family = AF_INET; target.sin_port = htons(port); target.sin_addr.s_addr = 0; if ( WSAStartup ( 0x0202, &wsaData ) ) { printf("WSAStartup failed!\n"); exit(0); // :) WSACleanup(); } sock = socket( AF_INET, SOCK_DGRAM, 0 ); if (sock == INVALID_SOCKET) { printf("invalid socket!\n"); exit(0); } if (bind(sock,(struct sockaddr*) &target, sizeof(struct sockaddr_in) ) == SOCKET_ERROR) { printf("failed to bind to port!\n"); exit(0); } printf("[UDPInterface::bindToPort] listening on port %i\n", port); } /* read */ bool UDPInterface::UDPEvent(Glib::IOCondition io_condition) { recvfrom(sock, (char*)buf, BUF_SIZE*4, 0, NULL, NULL); /* process packet... */ } /* glibmm connect */ Glib::RefPtr channel = Glib::IOChannel::create_from_win32_socket(udp.sock); Glib::signal_io().connect( sigc::mem_fun(udp, &UDPInterface::UDPEvent), channel, Glib::IO_IN ); I've read here in some other question, and also in glib docs (g_io_channel_win32_new_socket()) that the socket is put into nonblocking mode, and it's "a side-effect of the implementation and unavoidable". Does this explain the CPU effect, it's not clear to me? Whether or not I use glib to access the socket or call recvfrom() directly doesn't seem to make much difference, since CPU is used up before any packet arrives and the read handler gets invoked. Also glibmm docs state that it's ok to call recvfrom() even if the socket is polled (Glib::IOChannel::create_from_win32_socket()) I've tried compiling the program with -pg and created a per function cpu usage report with gprof. This wasn't usefull because the time is not spent in my program, but in some external glib/glibmm dll.

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• Why sockets does not die when server dies? Why socket dies when server is alive?

  - by Roman

  I try to play with sockets a bit. For that I wrote very simple "client" and "server" applications. Client: import java.net.*; public class client { public static void main(String[] args) throws Exception { InetAddress localhost = InetAddress.getLocalHost(); System.out.println("before"); Socket clientSideSocket = null; try { clientSideSocket = new Socket(localhost,12345,localhost,54321); } catch (ConnectException e) { System.out.println("Connection Refused"); } System.out.println("after"); if (clientSideSocket != null) { clientSideSocket.close(); } } } Server: import java.net.*; public class server { public static void main(String[] args) throws Exception { ServerSocket listener = new ServerSocket(12345); while (true) { Socket serverSideSocket = listener.accept(); System.out.println("A client-request is accepted."); } } } And I found a behavior that I cannot explain: I start a server, than I start a client. Connection is successfully established (client stops running and server is running). Then I close the server and start it again in a second. After that I start a client and it writes "Connection Refused". It seems to me that the server "remember" the old connection and does not want to open the second connection twice. But I do not understand how it is possible. Because I killed the previous server and started a new one! I do not start the server immediately after the previous one was killed (I wait like 20 seconds). In this case the server "forget" the socket from the previous server and accepts the request from the client. I start the server and then I start the client. Connection is established (server writes: "A client-request is accepted"). Then I wait a minute and start the client again. And server (which was running the whole time) accept the request again! Why? The server should not accept the request from the same client-IP and client-port but it does!

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• SQL/Schema comparison and upgrade

  - by Workshop Alex

  I have a simple situation. A large organisation is using several different versions of some (desktop) application and each version has it's own database structure. There are about 200 offices and each office will have it's own version, which can be one of 7 different ones. The company wants to upgrade all applications to the latest versions, which will be version 8. The problem is that they don't have a separate database for each version. Nor do they have a separate database for each office. They have one single database which is handled by a dedicated server, thus keeping things like management and backups easier. Every office has it's own database schema and within the schema there's the whole database structure for their specific application version. As a result, I'm dealing with 200 different schema's which need to be upgraded, each with 7 possible versions. Fortunately, every schema knows the proper version so checking the version isn't difficult. But my problem is that I need to create upgrade scripts which can upgrade from version 1 to version 2 to version 3 to etc... Basically, all schema's need to be bumped up one version until they're all version 8. Writing the code that will do this is no problem. the challenge is how to create the upgrade script from one version to the other? Preferably with some automated tool. I've examined RedGate's SQL Compare and Altova's DatabaseSpy but they're not practical. Altova is way too slow. RedGate requires too much processing afterwards, since the generated SQL Script still has a few errors and it refers to the schema name. Furthermore, the code needs to become part of a stored procedure and the code generated by RedGate doesn't really fit inside a single procedure. (Plus, it's doing too much transaction-handling, while I need everything within a single transaction. I have been considering using another SQL Comparison tool but it seems to me that my case is just too different from what standard tools can deliver. So I'm going to write my own comparison tool. To do this, I'll be using ADOX with Delphi to read the catalogues for every schema version in the database, then use this to write the SQL Statements that will need to upgrade these schema's to their next version. (Comparing 1 with 2, 2 with 3, 3 with 4, etc.) I'm not unfamiliar with generating SQL-Script-Generators so I don't expect too many problems. And I'll only be upgrading the table structures, not any of the other database objects. So, does anyone have some good tips and tricks to apply when doing this kind of comparisons? Things to be aware of? Practical tips to increase speed?

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• Android Bluetooth Fails to Pair

  - by CaseyB

  I am having a problem getting my devices to pair in Android. If I go into the settings and pair them manually I can get them to connect using the following code: Server // Make sure the device it discoverable mServerSocket = mAdapter.listenUsingRfcommWithServiceRecord("Moo Productions Bluetooth Server", mUUID); mState = State.ACCEPTING; BluetoothSocket socket = mServerSocket.accept(); mServerSocket.close(); connected(socket); Client Set<BluetoothDevice> pairedDevices = mAdapter.getBondedDevices(); BluetoothSocket socket = null; // Search the list of paired devices for the right one for(BluetoothDevice device : pairedDevices) { try { mState = State.SEARCHING; socket = device.createRfcommSocketToServiceRecord(mUUID); mState = State.CONNECTING; socket.connect(); connected(socket); break; } catch (IOException e) { socket = null; continue; } } But if the devices hadn't already been paired it gets out of the foreach without connecting to a valid socket. In that case I start discovering. // If that didn't work, discover if(socket == null) { mState = State.SEARCHING; mReceiver = new SocketReceiver(); mContext.registerReceiver(mReceiver, new IntentFilter(BluetoothDevice.ACTION_FOUND)); mAdapter.startDiscovery(); } // ... Later ... private class SocketReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { if(BluetoothDevice.ACTION_FOUND.equals(intent.getAction())) { try { // Get the device and try to open a socket BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE); BluetoothSocket socket = device.createRfcommSocketToServiceRecord(mUUID); mState = State.CONNECTING; socket.connect(); // This is our boy, so stop looking mAdapter.cancelDiscovery(); mContext.unregisterReceiver(mReceiver); connected(socket); } catch (IOException ioe) { ioe.printStackTrace(); } } } } But it will never find the other device. I never get a pairing dialog and when I step through I see that it discovers the correct device, but it fails to connect with this exception java.io.IOException: Service discovery failed. Any ideas as to what I'm missing?

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• linq to sql with nservicebus table lock issue

  - by IGoor

  I am building a system using NServiceBus and my DataLayer is using Linq 2 SQL. The system is made up of 2 services. Service1 receives messages from NSB. It will query Table1 in my database and inserts a record into Table1 If a certain condition is met a new NSB message is sent to the 2nd service Service2 will update records also in Table1 when it receives messages from Service1 and it does some other non database related work. Service2 is a long running process. The problem I am having is the moment Service2 updates a record in Table1, the table is locked. The lock seems to be in place until Service2 has completed all it is processing. i.e. The lock is not released after my datacontext is disposed. This causes the query in Service1 to timeout. Once Service2 completes processing, Service1 resumes processing again without problem. So for example Service1 code may look like: int x =0; using (DataContext db = new DataContext()) { x = (from dp in db.Table1 select dp).Count(); // this line will timeout while service2 is processing Table1 t = new Table1(); t.Data = "test"; db.Table1.InsertOnSubmit(t); db.SubmitChanges(); } if(x % 50 == 0) CallService2(); The code in service2 may look like: using (DataContext db = new DataContext()) { Table1 t = db.Table1.Where(t => t.id == myId); t.Data = "updated"; db.SubmitChanges(); } // I would have expected the lock to have been released at this point, but this is not the case. DoSomeLongRunningTasks(); // lock will be released once service2 exits I don't understand why the lock is not released when the datacontext is disposed in Service2. To get around the problem I have been calling: db.ExecuteCommand("SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED"); and this works, but I am not happy using it. I want to solve this problem properly. Has any one experienced this sort of problem before and does any one know how to solve it? Why is the lock not released after the datacontext has been disposed? Thanks in advance. p.s. sorry for the extremely long post.

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• Reading column header and column values of a data table using LAMBDA(C#3.0)

  - by Newbie

  Consider the folowing where I am reading the data table values and writing to a text file using (StreamWriter sw = new StreamWriter(@"C:\testwrite.txt",true)) { DataPreparation().AsEnumerable().ToList().ForEach(i => { string col1 = i[0].ToString(); string col2 = i[1].ToString(); string col3 = i[2].ToString(); string col4 = i[3].ToString(); sw.WriteLine( col1 + "\t" + col2 + "\t" + col3 + "\t" + col4 + Environment.NewLine ); }); } The data preparation function is as under private static DataTable DataPreparation() { DataTable dt = new DataTable(); dt.Columns.Add("Col1", typeof(string)); dt.Columns.Add("Col2", typeof(int)); dt.Columns.Add("Col3", typeof(DateTime)); dt.Columns.Add("Col4", typeof(bool)); for (int i = 0; i < 10; i++) { dt.Rows.Add("String" + i.ToString(), i, DateTime.Now.Date, (i % 2 == 0) ? true : false); } return dt; } It is working fine. Now in the above described program, it is known to me the Number of columns and the column headers. How to achieve the same in case when the column headers and number of columns are not known at compile time using the lambda expression? I have already done that which is as under public static void WriteToTxt(string directory, string FileName, DataTable outData, string delimiter) { FileStream fs = null; StreamWriter streamWriter = null; using (fs = new FileStream(directory + "\\" + FileName + ".txt", FileMode.Append, FileAccess.Write)) { try { streamWriter = new StreamWriter(fs); streamWriter.BaseStream.Seek(0, SeekOrigin.End); streamWriter.WriteLine(); DataTableReader datatableReader = outData.CreateDataReader(); for (int header = 0; header < datatableReader.FieldCount; header++) { streamWriter.Write(outData.Columns[header].ToString() + delimiter); } streamWriter.WriteLine(); int row = 0; while (datatableReader.Read()) { for (int field = 0; field < datatableReader.FieldCount; field++) { streamWriter.Write(outData.Rows[row][field].ToString() + delimiter); } streamWriter.WriteLine(); row++; } } catch (Exception ex) { throw ex; } } } I am using C#3.0 and framework 3.5 Thanks in advance

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• How to efficently build an interpreter (lexer+parser) in C?

  - by Rizo

  I'm trying to make a meta-language for writing markup code (such as xml and html) wich can be directly embedded into C/C++ code. Here is a simple sample written in this language, I call it WDI (Web Development Interface): /* * Simple wdi/html sample source code */ #include <mySite> string name = "myName"; string toCapital(string str); html { head { title { mySiteTitle; } link(rel="stylesheet", href="style.css"); } body(id="default") { // Page content wrapper div(id="wrapper", class="some_class") { h1 { "Hello, " + toCapital(name) + "!"; } // Lists post ul(id="post_list") { for(post in posts) { li { a(href=post.getID()) { post.tilte; } } } } } } } Basically it is a C source with a user-friendly interface for html. As you can see the traditional tag-based style is substituted by C-like, with blocks delimited by curly braces. I need to build an interpreter to translate this code to html and posteriorly insert it into C, so that it can be compiled. The C part stays intact. Inside the wdi source it is not necessary to use prints, every return statement will be used for output (in printf function). The program's output will be clean html code. So, for example a heading 1 tag would be transformed like this: h1 { "Hello, " + toCapital(name) + "!"; } // would become: printf("<h1>Hello, %s!</h1>", toCapital(name)); My main goal is to create an interpreter to translate wdi source to html like this: tag(attributes) {content} = <tag attributes>content</tag> Secondly, html code returned by the interpreter has to be inserted into C code with printfs. Variables and functions that occur inside wdi should also be sorted in order to use them as printf parameters (the case of toCapital(name) in sample source). I am searching for efficient (I want to create a fast parser) way to create a lexer and parser for wdi. Already tried flex and bison, but as I am not sure if they are the best tools. Are there any good alternatives? What is the best way to create such an interpreter? Can you advise some brief literature on this issue?

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