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  • NSURLConnection request seems to disappear into thin air

    - by ibergmark
    Hi Everybody! I'm having trouble with a NSURLConnection request. My app calls a routine called sayHello to identify a user's device. This code works fine for all devices I've tested it on, but for some devices the request just seems to disappear into thin air with no errors or popups on the device. One specific device that fails is an iPod Touch 2G running OS 3.1.3. The app start's fine and doesn't crash, and none of my error popup messages are displayed. I just can't understand why my server never receives the request since the call to initWithRequest returns a pointer. Any help is much appreciated. Thanks. Here's the relevant header info: @interface Globals : NSObject { UserItem *userData; NSURLConnection *urlConnection; NSString *imageCacheLocation; NSOperationQueue *opQueue; } Here's the implementation of sayHello: - (void)sayHello:(BOOL)updateVisits; { NSString *updString; if (updateVisits) updString = @"Y"; else updString = @"N"; NSDictionary *dataDict = [[NSDictionary alloc] initWithObjectsAndKeys: [[UIDevice currentDevice] uniqueIdentifier], @"id", kProgVersion, @"pv", @"1", @"pr", userData.tagID, @"tg", updString, @"uv", nil]; NSString *urlString = [[NSString alloc] initWithString:kHelloURL]; urlConnection = [self localPOST:dataDict toUrl:urlString delegate:self]; [dataDict release]; [urlString release]; } - (NSURLConnection *)localPOST:(NSDictionary *)dictionary toUrl:(NSString *)urlString delegate:(id)delegate { NSString *myBounds = [[NSString alloc] initWithString:@"0xKmYbOuNdArY"]; NSMutableData *myPostData = [[NSMutableData alloc] initWithCapacity:10]; NSArray *formKeys = [dictionary allKeys]; for (int i = 0; i < [formKeys count]; i++) { [myPostData appendData:[[NSString stringWithFormat:@"--%@\n", myBounds] dataUsingEncoding:NSUTF8StringEncoding]]; [myPostData appendData:[[NSString stringWithFormat: @"Content-Disposition: form-data; name=\"%@\"\n\n%@\n", [formKeys objectAtIndex:i], [dictionary valueForKey:[formKeys objectAtIndex:i]]] dataUsingEncoding:NSUTF8StringEncoding]]; } [myPostData appendData:[[NSString stringWithFormat:@"--%@--\n", myBounds] dataUsingEncoding:NSUTF8StringEncoding]]; NSURL *myURL = [[NSURL alloc] initWithString:urlString]; NSMutableURLRequest *myRequest = [[NSMutableURLRequest alloc] initWithURL:myURL cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:30]; NSString *myContent = [[NSString alloc] initWithFormat: @"multipart/form-data; boundary=%@", myBounds]; [myRequest setValue:myContent forHTTPHeaderField:@"Content-Type"]; [myRequest setHTTPMethod:@"POST"]; [myRequest setHTTPBody:myPostData]; NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:myRequest delegate:delegate]; if (!connection) { [[Globals sharedGlobals] showAlertWithTitle: NSLocalizedString( @"Connection failed", @"alert title - connection failed") message: NSLocalizedString( @"Could not open a connection.", @"alert message - connection failed")]; } [myBounds release]; [myPostData release]; [myURL release]; [myRequest release]; [myContent release]; return connection; } - (void)handleNetworkError:(NSError *)error { if (networkErrorAlert) return; networkErrorAlert = YES; [[Globals sharedGlobals] showAlertWithTitle: NSLocalizedString( @"Network error", @"alert title - network error") message: [NSString stringWithFormat: NSLocalizedString( @"This app needs a network connection to function properly.", @"alert message - network error")] otherButtons:nil delegate:self]; } - (void) connectionDidFinishLoading:(NSURLConnection *)connection { [urlConnection release]; urlConnection = nil; } - (void) connection:(NSURLConnection *)connection didFailWithError:(NSError *)error { [self handleNetworkError:error]; [urlConnection release]; urlConnection = nil; }

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  • Getting EOFException while trying to read from SSLSocket

    - by Isac
    Hi, I am developing a SSL client that will do a simple request to a SSL server and wait for the response. The SSL handshake and the writing goes OK but I can't READ data from the socket. I turned on the debug of java.net.ssl and got the following: [..] main, READ: TLSv1 Change Cipher Spec, length = 1 [Raw read]: length = 5 0000: 16 03 01 00 20 .... [Raw read]: length = 32 [..] main, READ: TLSv1 Handshake, length = 32 Padded plaintext after DECRYPTION: len = 32 [..] * Finished verify_data: { 29, 1, 139, 226, 25, 1, 96, 254, 176, 51, 206, 35 } %% Didn't cache non-resumable client session: [Session-1, SSL_RSA_WITH_RC4_128_MD5] [read] MD5 and SHA1 hashes: len = 16 0000: 14 00 00 0C 1D 01 8B E2 19 01 60 FE B0 33 CE 23 ..........`..3.# Padded plaintext before ENCRYPTION: len = 70 [..] a.j.y. main, WRITE: TLSv1 Application Data, length = 70 [Raw write]: length = 75 [..] Padded plaintext before ENCRYPTION: len = 70 [..] main, WRITE: TLSv1 Application Data, length = 70 [Raw write]: length = 75 [..] main, received EOFException: ignored main, called closeInternal(false) main, SEND TLSv1 ALERT: warning, description = close_notify Padded plaintext before ENCRYPTION: len = 18 [..] main, WRITE: TLSv1 Alert, length = 18 [Raw write]: length = 23 [..] main, called close() main, called closeInternal(true) main, called close() main, called closeInternal(true) The [..] are the certificate chain. Here is a code snippet: try { System.setProperty("javax.net.debug","all"); /* * Set up a key manager for client authentication * if asked by the server. Use the implementation's * default TrustStore and secureRandom routines. */ SSLSocketFactory factory = null; try { SSLContext ctx; KeyManagerFactory kmf; KeyStore ks; char[] passphrase = "importkey".toCharArray(); ctx = SSLContext.getInstance("TLS"); kmf = KeyManagerFactory.getInstance("SunX509"); ks = KeyStore.getInstance("JKS"); ks.load(new FileInputStream("keystore.jks"), passphrase); kmf.init(ks, passphrase); ctx.init(kmf.getKeyManagers(), null, null); factory = ctx.getSocketFactory(); } catch (Exception e) { throw new IOException(e.getMessage()); } SSLSocket socket = (SSLSocket)factory.createSocket("server ip", 9999); /* * send http request * * See SSLSocketClient.java for more information about why * there is a forced handshake here when using PrintWriters. */ SSLSession session = socket.getSession(); [build query] byte[] buff = query.toWire(); out.write(buff); out.flush(); InputStream input = socket.getInputStream(); int readBytes = -1; int randomLength = 1024; byte[] buffer = new byte[randomLength]; while((readBytes = input.read(buffer, 0, randomLength)) != -1) { LOG.debug("Read: " + new String(buffer)); } input.close(); socket.close(); } catch (Exception e) { e.printStackTrace(); } I can write multiple times and I don't get any error but the EOFException happens on the first read. Am I doing something wrong with the socket or with the SSL authentication? Thank you.

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  • multi_index composite_key replace with iterator

    - by Rohit
    Is there anyway to loop through an index in a boost::multi_index and perform a replace? #include <iostream> #include <string> #include <boost/multi_index_container.hpp> #include <boost/multi_index/composite_key.hpp> #include <boost/multi_index/member.hpp> #include <boost/multi_index/ordered_index.hpp> using namespace boost::multi_index; using namespace std; struct name_record { public: name_record(string given_name_,string family_name_,string other_name_) { given_name=given_name_; family_name=family_name_; other_name=other_name_; } string given_name; string family_name; string other_name; string get_name() const { return given_name + " " + family_name + " " + other_name; } void setnew(string chg) { given_name = given_name + chg; family_name = family_name + chg; } }; struct NameIndex{}; typedef multi_index_container< name_record, indexed_by< ordered_non_unique< tag<NameIndex>, composite_key < name_record, BOOST_MULTI_INDEX_MEMBER(name_record,string, name_record::given_name), BOOST_MULTI_INDEX_MEMBER(name_record,string, name_record::family_name) > > > > name_record_set; typedef boost::multi_index::index<name_record_set,NameIndex>::type::iterator IteratorType; typedef boost::multi_index::index<name_record_set,NameIndex>::type NameIndexType; void printContainer(name_record_set & ns) { cout << endl << "PrintContainer" << endl << "-------------" << endl; IteratorType it1 = ns.begin(); IteratorType it2 = ns.end (); while (it1 != it2) { cout<<it1->get_name()<<endl; it1++; } cout << "--------------" << endl << endl; } void modifyContainer(name_record_set & ns) { cout << endl << "ModifyContainer" << endl << "-------------" << endl; IteratorType it3; IteratorType it4; NameIndexType & idx1 = ns.get<NameIndex>(); IteratorType it1 = idx1.begin(); IteratorType it2 = idx1.end(); while (it1 != it2) { cout<<it1->get_name()<<endl; name_record nr = *it1; nr.setnew("_CHG"); bool res = idx1.replace(it1,nr); cout << "result is: " << res << endl; it1++; } cout << "--------------" << endl << endl; } int main() { name_record_set ns; ns.insert( name_record("Joe","Smith","ENTRY1") ); ns.insert( name_record("Robert","Brown","ENTRY2") ); ns.insert( name_record("Robert","Nightingale","ENTRY3") ); ns.insert( name_record("Marc","Tuxedo","ENTRY4") ); printContainer (ns); modifyContainer (ns); printContainer (ns); return 0; } PrintContainer ------------- Joe Smith ENTRY1 Marc Tuxedo ENTRY4 Robert Brown ENTRY2 Robert Nightingale ENTRY3 -------------- ModifyContainer ------------- Joe Smith ENTRY1 result is: 1 Marc Tuxedo ENTRY4 result is: 1 Robert Brown ENTRY2 result is: 1 -------------- PrintContainer ------------- Joe_CHG Smith_CHG ENTRY1 Marc_CHG Tuxedo_CHG ENTRY4 Robert Nightingale ENTRY3 Robert_CHG Brown_CHG ENTRY2 --------------

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  • Adding functionality to any TextReader

    - by strager
    I have a Location class which represents a location somewhere in a stream. (The class isn't coupled to any specific stream.) The location information will be used to match tokens to location in the input in my parser, to allow for nicer error reporting to the user. I want to add location tracking to a TextReader instance. This way, while reading tokens, I can grab the location (which is updated by the TextReader as data is read) and give it to the token during the tokenization process. I am looking for a good approach on accomplishing this goal. I have come up with several designs. Manual location tracking Every time I need to read from the TextReader, I call AdvanceString on the Location object of the tokenizer with the data read. Advantages Very simple. No class bloat. No need to rewrite the TextReader methods. Disadvantages Couples location tracking logic to tokenization process. Easy to forget to track something (though unit testing helps with this). Bloats existing code. Plain TextReader wrapper Create a LocatedTextReaderWrapper class which surrounds each method call, tracking a Location property. Example: public class LocatedTextReaderWrapper : TextReader { private TextReader source; public Location Location { get; set; } public LocatedTextReaderWrapper(TextReader source) : this(source, new Location()) { } public LocatedTextReaderWrapper(TextReader source, Location location) { this.Location = location; this.source = source; } public override int Read(char[] buffer, int index, int count) { int ret = this.source.Read(buffer, index, count); if(ret >= 0) { this.location.AdvanceString(string.Concat(buffer.Skip(index).Take(count))); } return ret; } // etc. } Advantages Tokenization doesn't know about Location tracking. Disadvantages User needs to create and dispose a LocatedTextReaderWrapper instance, in addition to their TextReader instance. Doesn't allow different types of tracking or different location trackers to be added without layers of wrappers. Event-based TextReader wrapper Like LocatedTextReaderWrapper, but decouples it from the Location object raising an event whenever data is read. Advantages Can be reused for other types of tracking. Tokenization doesn't know about Location tracking or other tracking. Can have multiple, independent Location objects (or other methods of tracking) tracking at once. Disadvantages Requires boilerplate code to enable location tracking. User needs to create and dispose the wrapper instance, in addition to their TextReader instance. Aspect-orientated approach Use AOP to perform like the event-based wrapper approach. Advantages Can be reused for other types of tracking. Tokenization doesn't know about Location tracking or other tracking. No need to rewrite the TextReader methods. Disadvantages Requires external dependencies, which I want to avoid. I am looking for the best approach in my situation. I would like to: Not bloat the tokenizer methods with location tracking. Not require heavy initialization in user code. Not have any/much boilerplate/duplicated code. (Perhaps) not couple the TextReader with the Location class. Any insight into this problem and possible solutions or adjustments are welcome. Thanks! (For those who want a specific question: What is the best way to wrap the functionality of a TextReader?) I have implemented the "Plain TextReader wrapper" and "Event-based TextReader wrapper" approaches and am displeased with both, for reasons mentioned in their disadvantages.

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  • MODI leaking memory

    - by Khragg
    I have an app where I'm using MODI 2007 to OCR several multi-page tiff files. I have found that when I kick it off on a directory that contains several good tiffs but also some tiffs that cannot be opened in Windows Picture and Fax Viewer, then MODI also fails to OCR those "bad" tiffs. When this happens, the app is unable to reclaim any of the memory that was used by MODI to OCR those tiffs. After the tool tries to OCR too many of these "bad" tiffs, the machine runs out of memory and the app crashes. I have tried several code fixes from the web that supposedly fix any MODI memory leaks, but so far none have worked for me. I am pasting in the part of the code below that does the OCRing: StringBuilder strRecText = new StringBuilder(10000); MODI.Document doc1 = new MODI.Document(); doc1.Create(name); try { doc1.OCR(MODI.MiLANGUAGES.miLANG_ENGLISH, true, true); // this will ocr all pages of a multi-page tiff file } catch (Exception e) { doc1.Close(false); // clean up if (doc1 != null) { GC.Collect(); GC.WaitForPendingFinalizers(); GC.Collect(); GC.WaitForPendingFinalizers(); System.Runtime.InteropServices.Marshal.FinalReleaseComObject(doc1); doc1 = null; } } MODI.Images images = doc1.Images; for (int imageCounter = 0; imageCounter < images.Count; imageCounter++) { if (imageCounter > 0) { if (!noPageBreakFlag) { strRecText.Append((char)pageBreakChar); } } MODI.Image image = (MODI.Image)images[imageCounter]; MODI.Layout layout = image.Layout; strRecText.Append(layout.Text); GC.Collect(); GC.WaitForPendingFinalizers(); GC.Collect(); GC.WaitForPendingFinalizers(); if (layout != null) { System.Runtime.InteropServices.Marshal.FinalReleaseComObject(layout); layout = null; } if (image != null) { System.Runtime.InteropServices.Marshal.FinalReleaseComObject(image); image = null; } } File.AppendAllText(ocrFile, strRecText.ToString()); // write the OCR file out to disk GC.Collect(); GC.WaitForPendingFinalizers(); GC.Collect(); GC.WaitForPendingFinalizers(); if (images != null) { System.Runtime.InteropServices.Marshal.FinalReleaseComObject(images); images = null; } GC.Collect(); GC.WaitForPendingFinalizers(); GC.Collect(); GC.WaitForPendingFinalizers(); doc1.Close(false); // clean up if (doc1 != null) { System.Runtime.InteropServices.Marshal.FinalReleaseComObject(doc1); doc1 = null; } GC.Collect(); GC.WaitForPendingFinalizers(); GC.Collect(); GC.WaitForPendingFinalizers();

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  • LLVM JIT segfaults. What am I doing wrong?

    - by bugspy.net
    It is probably something basic because I am just starting to learn LLVM.. The following creates a factorial function and tries to git and execute it (I know the generated func is correct because I was able to static compile and execute it). But I get segmentation fault upon execution of the function (in EE-runFunction(TheF, Args)) #include <iostream> #include "llvm/Module.h" #include "llvm/Function.h" #include "llvm/PassManager.h" #include "llvm/CallingConv.h" #include "llvm/Analysis/Verifier.h" #include "llvm/Assembly/PrintModulePass.h" #include "llvm/Support/IRBuilder.h" #include "llvm/Support/raw_ostream.h" #include "llvm/ExecutionEngine/JIT.h" #include "llvm/ExecutionEngine/GenericValue.h" using namespace llvm; Module* makeLLVMModule() { // Module Construction LLVMContext& ctx = getGlobalContext(); Module* mod = new Module("test", ctx); Constant* c = mod->getOrInsertFunction("fact64", /*ret type*/ IntegerType::get(ctx,64), IntegerType::get(ctx,64), /*varargs terminated with null*/ NULL); Function* fact64 = cast<Function>(c); fact64->setCallingConv(CallingConv::C); /* Arg names */ Function::arg_iterator args = fact64->arg_begin(); Value* x = args++; x->setName("x"); /* Body */ BasicBlock* block = BasicBlock::Create(ctx, "entry", fact64); BasicBlock* xLessThan2Block= BasicBlock::Create(ctx, "xlst2_block", fact64); BasicBlock* elseBlock = BasicBlock::Create(ctx, "else_block", fact64); IRBuilder<> builder(block); Value *One = ConstantInt::get(Type::getInt64Ty(ctx), 1); Value *Two = ConstantInt::get(Type::getInt64Ty(ctx), 2); Value* xLessThan2 = builder.CreateICmpULT(x, Two, "tmp"); //builder.CreateCondBr(xLessThan2, xLessThan2Block, cond_false_2); builder.CreateCondBr(xLessThan2, xLessThan2Block, elseBlock); /* Recursion */ builder.SetInsertPoint(elseBlock); Value* xMinus1 = builder.CreateSub(x, One, "tmp"); std::vector<Value*> args1; args1.push_back(xMinus1); Value* recur_1 = builder.CreateCall(fact64, args1.begin(), args1.end(), "tmp"); Value* retVal = builder.CreateBinOp(Instruction::Mul, x, recur_1, "tmp"); builder.CreateRet(retVal); /* x<2 */ builder.SetInsertPoint(xLessThan2Block); builder.CreateRet(One); return mod; } int main(int argc, char**argv) { long long x; if(argc > 1) x = atol(argv[1]); else x = 4; Module* Mod = makeLLVMModule(); verifyModule(*Mod, PrintMessageAction); PassManager PM; PM.add(createPrintModulePass(&outs())); PM.run(*Mod); // Now we going to create JIT ExecutionEngine *EE = EngineBuilder(Mod).create(); // Call the function with argument x: std::vector<GenericValue> Args(1); Args[0].IntVal = APInt(64, x); Function* TheF = cast<Function>(Mod->getFunction("fact64")) ; /* The following CRASHES.. */ GenericValue GV = EE->runFunction(TheF, Args); outs() << "Result: " << GV.IntVal << "\n"; delete Mod; return 0; }

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  • Managing highly repetitive code and documentation in Java

    - by polygenelubricants
    Highly repetitive code is generally a bad thing, and there are design patterns that can help minimize this. However, sometimes it's simply inevitable due to the constraints of the language itself. Take the following example from java.util.Arrays: /** * Assigns the specified long value to each element of the specified * range of the specified array of longs. The range to be filled * extends from index <tt>fromIndex</tt>, inclusive, to index * <tt>toIndex</tt>, exclusive. (If <tt>fromIndex==toIndex</tt>, the * range to be filled is empty.) * * @param a the array to be filled * @param fromIndex the index of the first element (inclusive) to be * filled with the specified value * @param toIndex the index of the last element (exclusive) to be * filled with the specified value * @param val the value to be stored in all elements of the array * @throws IllegalArgumentException if <tt>fromIndex &gt; toIndex</tt> * @throws ArrayIndexOutOfBoundsException if <tt>fromIndex &lt; 0</tt> or * <tt>toIndex &gt; a.length</tt> */ public static void fill(long[] a, int fromIndex, int toIndex, long val) { rangeCheck(a.length, fromIndex, toIndex); for (int i=fromIndex; i<toIndex; i++) a[i] = val; } The above snippet appears in the source code 8 times, with very little variation in the documentation/method signature but exactly the same method body, one for each of the root array types int[], short[], char[], byte[], boolean[], double[], float[], and Object[]. I believe that unless one resorts to reflection (which is an entirely different subject in itself), this repetition is inevitable. I understand that as a utility class, such high concentration of repetitive Java code is highly atypical, but even with the best practice, repetition does happen! Refactoring doesn't always work because it's not always possible (the obvious case is when the repetition is in the documentation). Obviously maintaining this source code is a nightmare. A slight typo in the documentation, or a minor bug in the implementation, is multiplied by however many repetitions was made. In fact, the best example happens to involve this exact class: Google Research Blog - Extra, Extra - Read All About It: Nearly All Binary Searches and Mergesorts are Broken (by Joshua Bloch, Software Engineer) The bug is a surprisingly subtle one, occurring in what many thought to be just a simple and straightforward algorithm. // int mid =(low + high) / 2; // the bug int mid = (low + high) >>> 1; // the fix The above line appears 11 times in the source code! So my questions are: How are these kinds of repetitive Java code/documentation handled in practice? How are they developed, maintained, and tested? Do you start with "the original", and make it as mature as possible, and then copy and paste as necessary and hope you didn't make a mistake? And if you did make a mistake in the original, then just fix it everywhere, unless you're comfortable with deleting the copies and repeating the whole replication process? And you apply this same process for the testing code as well? Would Java benefit from some sort of limited-use source code preprocessing for this kind of thing? Perhaps Sun has their own preprocessor to help write, maintain, document and test these kind of repetitive library code? A comment requested another example, so I pulled this one from Google Collections: com.google.common.base.Predicates lines 276-310 (AndPredicate) vs lines 312-346 (OrPredicate). The source for these two classes are identical, except for: AndPredicate vs OrPredicate (each appears 5 times in its class) "And(" vs Or(" (in the respective toString() methods) #and vs #or (in the @see Javadoc comments) true vs false (in apply; ! can be rewritten out of the expression) -1 /* all bits on */ vs 0 /* all bits off */ in hashCode() &= vs |= in hashCode()

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  • JAVA: POST data via HTTPS does not seem to get sent?

    - by ostollmann
    Hi guys (and girls), I have a problem POSTing data via HTTPS in Java. The server response is the same whether or not I send 'query'. Maybe someone can point out what the problem is... Thanks! Main class: package bind; public class Main { public static final String urlString = "https://www.sms.ethz.ch/cgi-bin/sms/send.pl"; public static void main(String[] args) { Message msg = new Message("Alles klar?"); URL url = new URL(urlString); String[][] values = new String[3][2]; values[0][0] = "action"; values[0][1] = "listoriginators"; values[1][0] = "username"; values[1][1] = "xxxxxx"; values[2][0] = "password"; values[2][1] = "xxxxxx"; Query query = new Query(values); System.out.println("Query: " + query.getQuery()); Request request = new Request(url.getURL(), query.getQuery()); } } Request class: package bind; public class Request { static private int ic = 0; private URL url; protected Request(java.net.URL URL, String query){ ic++; if(CONSTANTS.SHOW_LOGS) { System.out.println("log: new instance of 'Message'"); } // connect try { System.setProperty("java.protocol.handler.pkgs", "com.sun.net.ssl.internal.www.protocol"); java.security.Security.addProvider(new com.sun.net.ssl.internal.ssl.Provider()); javax.net.ssl.HttpsURLConnection connection = (javax.net.ssl.HttpsURLConnection) URL.openConnection(); connection.setDoInput(true); connection.setDoOutput(true); connection.setRequestMethod("POST"); connection.setFollowRedirects(true); connection.setRequestProperty("Content-Length", String.valueOf(query.length())); connection.setRequestProperty("Content-Type", "application/x-www- form-urlencoded"); connection.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"); java.io.DataOutputStream output = new java.io.DataOutputStream(connection.getOutputStream()); output.writeBytes(query); // <<-- NOTHING CHANGES IF I COMMENT THIS OUT OR NOT !!??!?! System.out.println("log: response code: " + connection.getResponseCode()); System.out.println("log: response message: " + connection.getResponseMessage()); java.io.DataInputStream input = new java.io.DataInputStream(connection.getInputStream()); for(int i = input.read(); i != -1; i = input.read()) { System.out.print((char)i); } System.out.print("\n"); input.close(); } catch(java.io.IOException e) { if(CONSTANTS.SHOW_LOGS) { System.out.println("error: unable to connect"); System.out.println(e); e.printStackTrace(); } } } } URL Class: public class URL { static private int ic = 0; private String URLString; private java.net.URL url; protected URL(String a_url){ ic++; if(CONSTANTS.SHOW_LOGS) { System.out.println("log: new instance of 'URL'"); } setURLString(a_url); createURL(); } private void setURLString(String a_url) { URLString = a_url; } private void createURL() { try { url = new java.net.URL(URLString); } catch(java.net.MalformedURLException e) { System.out.println("error: invalid URL"); System.out.println(e); e.printStackTrace(); } } private void showURL() { System.out.println("URL: " + url.getHost() + url.getPath()); } public java.net.URL getURL() { return url; } } PS: mostly from here: http://www.java-samples.com/java/POST-toHTTPS-url-free-java-sample-program.htm

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  • Performance surprise with "as" and nullable types

    - by Jon Skeet
    I'm just revising chapter 4 of C# in Depth which deals with nullable types, and I'm adding a section about using the "as" operator, which allows you to write: object o = ...; int? x = o as int?; if (x.HasValue) { ... // Use x.Value in here } I thought this was really neat, and that it could improve performance over the C# 1 equivalent, using "is" followed by a cast - after all, this way we only need to ask for dynamic type checking once, and then a simple value check. This appears not to be the case, however. I've included a sample test app below, which basically sums all the integers within an object array - but the array contains a lot of null references and string references as well as boxed integers. The benchmark measures the code you'd have to use in C# 1, the code using the "as" operator, and just for kicks a LINQ solution. To my astonishment, the C# 1 code is 20 times faster in this case - and even the LINQ code (which I'd have expected to be slower, given the iterators involved) beats the "as" code. Is the .NET implementation of isinst for nullable types just really slow? Is it the additional unbox.any that causes the problem? Is there another explanation for this? At the moment it feels like I'm going to have to include a warning against using this in performance sensitive situations... Results: Cast: 10000000 : 121 As: 10000000 : 2211 LINQ: 10000000 : 2143 Code: using System; using System.Diagnostics; using System.Linq; class Test { const int Size = 30000000; static void Main() { object[] values = new object[Size]; for (int i = 0; i < Size - 2; i += 3) { values[i] = null; values[i+1] = ""; values[i+2] = 1; } FindSumWithCast(values); FindSumWithAs(values); FindSumWithLinq(values); } static void FindSumWithCast(object[] values) { Stopwatch sw = Stopwatch.StartNew(); int sum = 0; foreach (object o in values) { if (o is int) { int x = (int) o; sum += x; } } sw.Stop(); Console.WriteLine("Cast: {0} : {1}", sum, (long) sw.ElapsedMilliseconds); } static void FindSumWithAs(object[] values) { Stopwatch sw = Stopwatch.StartNew(); int sum = 0; foreach (object o in values) { int? x = o as int?; if (x.HasValue) { sum += x.Value; } } sw.Stop(); Console.WriteLine("As: {0} : {1}", sum, (long) sw.ElapsedMilliseconds); } static void FindSumWithLinq(object[] values) { Stopwatch sw = Stopwatch.StartNew(); int sum = values.OfType<int>().Sum(); sw.Stop(); Console.WriteLine("LINQ: {0} : {1}", sum, (long) sw.ElapsedMilliseconds); } }

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  • Modelsim (XE III/Starter 6.4b) not allowing me to define a macro function

    - by montooner
    I'm working on a Xiling FPGA for a course project. Normally we use the lab computers, but I'm trying to install on my own computer. So, I'm trying to include a macro file using line: `include "Const.v" But the following macro function doesn't work. Any ideas why? `ifdef synthesis // if Synplify `define SYNPLIFY `define SYNTHESIS `define MACROSAFE `else // if not Synplify `ifdef MODELSIM `define SIMULATION `define MACROSAFE `else `define XST // synthesis translate_off // if XST then stop compiling `undef XST `define SIMULATION `define MODELSIM // synthesis translate_on // if XST then resume compiling `ifdef XST `define SYNTHESIS `define MACROSAFE `endif `endif `endif //------------------------------------------------------------------------------ //------------------------------------------------------------------------------ // Section: Log2 Macro // Desc: A macro to take the log base 2 of any number. Useful for // calculating bitwidths. Warning, this actually calculates // log2(x-1), not log2(x). //------------------------------------------------------------------------------ `ifdef MACROSAFE `define log2(x) ((((x) > 1) ? 1 : 0) + \ (((x) > 2) ? 1 : 0) + \ (((x) > 4) ? 1 : 0) + \ (((x) > 8) ? 1 : 0) + \ (((x) > 16) ? 1 : 0) + \ (((x) > 32) ? 1 : 0) + \ (((x) > 64) ? 1 : 0) + \ (((x) > 128) ? 1 : 0) + \ (((x) > 256) ? 1 : 0) + \ (((x) > 512) ? 1 : 0) + \ (((x) > 1024) ? 1 : 0) + \ (((x) > 2048) ? 1 : 0) + \ (((x) > 4096) ? 1 : 0) + \ (((x) > 8192) ? 1 : 0) + \ (((x) > 16384) ? 1 : 0) + \ (((x) > 32768) ? 1 : 0) + \ (((x) > 65536) ? 1 : 0) + \ (((x) > 131072) ? 1 : 0) + \ (((x) > 262144) ? 1 : 0) + \ (((x) > 524288) ? 1 : 0) + \ (((x) > 1048576) ? 1 : 0) + \ (((x) > 2097152) ? 1 : 0) + \ (((x) > 4194304) ? 1 : 0) + \ (((x) > 8388608) ? 1 : 0) + \ (((x) > 16777216) ? 1 : 0) + \ (((x) > 33554432) ? 1 : 0) + \ (((x) > 67108864) ? 1 : 0) + \ (((x) > 134217728) ? 1 : 0) + \ (((x) > 268435456) ? 1 : 0) + \ (((x) > 536870912) ? 1 : 0) + \ (((x) > 1073741824) ? 1 : 0)) `endif

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  • Running 32 bit assembly code on a 64 bit Linux & 64 bit Processor : Explain the anomaly.

    - by claws
    Hello, I'm in an interesting problem.I forgot I'm using 64bit machine & OS and wrote a 32 bit assembly code. I don't know how to write 64 bit code. This is the x86 32-bit assembly code for Gnu Assembler (AT&T syntax) on Linux. //hello.S #include <asm/unistd.h> #include <syscall.h> #define STDOUT 1 .data hellostr: .ascii "hello wolrd\n"; helloend: .text .globl _start _start: movl $(SYS_write) , %eax //ssize_t write(int fd, const void *buf, size_t count); movl $(STDOUT) , %ebx movl $hellostr , %ecx movl $(helloend-hellostr) , %edx int $0x80 movl $(SYS_exit), %eax //void _exit(int status); xorl %ebx, %ebx int $0x80 ret Now, This code should run fine on a 32bit processor & 32 bit OS right? As we know 64 bit processors are backward compatible with 32 bit processors. So, that also wouldn't be a problem. The problem arises because of differences in system calls & call mechanism in 64-bit OS & 32-bit OS. I don't know why but they changed the system call numbers between 32-bit linux & 64-bit linux. asm/unistd_32.h defines: #define __NR_write 4 #define __NR_exit 1 asm/unistd_64.h defines: #define __NR_write 1 #define __NR_exit 60 Anyway using Macros instead of direct numbers is paid off. Its ensuring correct system call numbers. when I assemble & link & run the program. $cpp hello.S hello.s //pre-processor $as hello.s -o hello.o //assemble $ld hello.o // linker : converting relocatable to executable Its not printing helloworld. In gdb its showing: Program exited with code 01. I don't know how to debug in gdb. using tutorial I tried to debug it and execute instruction by instruction checking registers at each step. its always showing me "program exited with 01". It would be great if some on could show me how to debug this. (gdb) break _start Note: breakpoint -10 also set at pc 0x4000b0. Breakpoint 8 at 0x4000b0 (gdb) start Function "main" not defined. Make breakpoint pending on future shared library load? (y or [n]) y Temporary breakpoint 9 (main) pending. Starting program: /home/claws/helloworld Program exited with code 01. (gdb) info breakpoints Num Type Disp Enb Address What 8 breakpoint keep y 0x00000000004000b0 <_start> 9 breakpoint del y <PENDING> main I tried running strace. This is its output: execve("./helloworld", ["./helloworld"], [/* 39 vars */]) = 0 write(0, NULL, 12 <unfinished ... exit status 1> Explain the parameters of write(0, NULL, 12) system call in the output of strace? What exactly is happening? I want to know the reason why exactly its exiting with exitstatus=1? Can some one please show me how to debug this program using gdb? Why did they change the system call numbers? Kindly change this program appropriately so that it can run correctly on this machine. EDIT: After reading Paul R's answer. I checked my files claws@claws-desktop:~$ file ./hello.o ./hello.o: ELF 64-bit LSB relocatable, x86-64, version 1 (SYSV), not stripped claws@claws-desktop:~$ file ./hello ./hello: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), statically linked, not stripped All of my questions still hold true. What exactly is happening in this case? Can someone please answer my questions and provide an x86-64 version of this code?

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  • Qwt plot not working , simple plot curve not appeat

    - by user1629213
    I followed the example of simple plot in qwt examples to plot a curve. The axis and the graph appear in the Qt main window user interface but the curve not. I assigned values to fit the curve but the curve not appear. Any suggestions and help how to solve the problem? Here is my code MainWindow::MainWindow( int argc, char** argv, QWidget *parent ) : QMainWindow( parent ) , qnode( argc,argv ) { ui.setupUi( this ); // Calling this incidentally connects all ui's triggers to on_...() callbacks in this class. QObject::connect( ui.actionAbout_Qt, SIGNAL( triggered( bool )), qApp, SLOT( aboutQt( ))); // qApp is a global variable for the application ReadSettings( ); setWindowIcon( QIcon( ":/images/icon.png" )); ui.tab_manager->setCurrentIndex( 0 ); // ensure the first tab is showing - qt-designer should have this already hardwired, but often loses it (settings?). QObject::connect( &qnode, SIGNAL( rosShutdown( )), this, SLOT( close( ))); /********************* ** Logging **********************/ ui.view_logging->setModel( qnode.loggingModel( )); QObject::connect( &qnode, SIGNAL( loggingUpdated( )), this, SLOT( updateLoggingView( ))); QObject::connect( &qnode, SIGNAL( graphReceived( )), this, SLOT( onGraphReceived( ))); QObject::connect( &qnode, SIGNAL( parameterReceived( )), this, SLOT( onParameterReceived( ))); /********************* ** Auto Start **********************/ if ( ui.checkbox_remember_settings->isChecked( )) { on_button_connect_clicked( true ); } ui.parameters->setAttribute( Qt::WA_NoMousePropagation ); ui.parameters->setAttribute( Qt::WA_OpaquePaintEvent ); ui.plotgraph->setAttribute( Qt::WA_NoMousePropagation ); ui.plotgraph->setAttribute( Qt::WA_OpaquePaintEvent ); p_plot = new QwtPlot(ui.plotgraph); p_plot->setTitle( "Plot LinVel" ); p_plot->setCanvasBackground( Qt::white ); // Axis p_plot->setAxisTitle( QwtPlot::xBottom, "Time(sec)" ); p_plot->setAxisTitle( QwtPlot::yLeft, "Linear Velocity (m/sec)" ); p_plot->setAxisScale( QwtPlot::yLeft, 0.0, 10.0 ); p_plot->setAxisScale( QwtPlot::xBottom, 0.0, 50.0 ); p_plot->insertLegend( new QwtLegend() ); //samplingThread.start(); QwtPlotGrid *grid = new QwtPlotGrid(); grid->attach( p_plot ); curve = new QwtPlotCurve(); curve->setTitle( "Linear velocity" ); // Set curve styles curve->setPen( Qt::blue, 4 ), curve->setRenderHint( QwtPlotItem::RenderAntialiased, true ); QwtSymbol *symbol = new QwtSymbol( QwtSymbol::Ellipse, QBrush( Qt::yellow), QPen( Qt::red, 2 ), QSize( 8, 8 ) ); curve->setSymbol( symbol); // Assign values to the curve //curve->setSamples(ui.plotgraph.get_linv_g());//yaw_g,trav_g,wall_g; curve->attach( p_plot ); p_plot->resize( 600, 400 ); p_plot->show(); void MainWindow::onGraphReceived( ) { { QMutexLocker locker( &qnode.m_mutex ); } } void MainWindow::onParameterReceived( ) { { QMutexLocker locker( &qnode.m_mutex ); std::vector<double> p_ = qnode.get_parameters(); std::cout << p_[0]<<" "<<p_[1]<<" "<<p_[2]<<" "<<p_[3]<<" "<<p_[4] << std::endl; } } Any help?

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  • eXML-PARSER output contains unwanted hash references

    - by seaworthy
    So I wrote a parser routine to take one xml file and reparse into another one. This code I later modified to split a large xml file into many small xml files. I am having a problem with an output. Parsing works fine the only thing output also includes unwanted strings like HASH(0x19f9b58), I am not sure why and need set of friendly eyes. use Encode; use XML::Parser; my $parser = XML::Parser->new( Handlers => {Start => \&handle_elem_start, End => \&handle_elem_end,Char => \&handle_char_data,}); my $record; my $file = shift @ARGV; if( $file ) {$parser->parsefile( $file );} exit; sub handle_elem_start { my( $expat, $name, %atts ) = @_; if ($name eq 'articles'){$file="_data.xml";unlink($file);} $record .= "<"; $record .= "$name"; foreach my $key (keys %atts){$record .= " $key=\"$atts{$key}\"";} $record .= ">"; } sub handle_char_data { my( $expat, $text ) = @_; $text = decode_utf8( $text ); $record .= "$text"; } sub handle_elem_end { my( $expat, $name ) = @_; $record .= "</$name>"; if( $name eq 'article' ) { open (MYFILE, '>>'.$file); print MYFILE $record; close (MYFILE); print $record; $record = {}; } return unless( $name eq 'article' ); } Sample output: ... </article>HASH(0x19f9b40) <article doi="10.1103/PhysRevSeriesI.9.304"> <journal short="Phys. Rev. (Series I)" jcode="PRI">Physical Review (Series I)</journal> <volume>9</volume> <issue printdate="1899-11-00">5</issue> <fpage>304</fpage> <lpage>309</lpage> <seqno>1</seqno> <price></price><tocsec>Articles</tocsec> <arttype type="article"></arttype><doi>10.1103/PhysRevSeriesI.9.304</doi> <title>An Investigation of the Magnetic Qualities of Building Brick</title> <authgrp> <author><givenname>O.</givenname><middlename>A.</middlename><surname>Gage</surname></author> <author><givenname>H.</givenname><middlename>E.</middlename><surname>Lawrence</surname></author> </authgrp> <cpyrt> <cpyrtdate date="1899"></cpyrtdate><cpyrtholder>The American Physical Society</cpyrtholder> </cpyrt> </article>HASH(0x19f9b58) ... HASH strings are not wanted, please advise.

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  • jQuery dynamic field classes not being assigned as desired.

    - by Simon
    Hello, I'm working on a fancy login page with 4 unique states attributed through classes for each field (normal, focus, active-on, active-off). Normal is the default style. Focus is the focus style when nothing is typed. Active-on is the focus style when something has been typed. Active-off is for field that have user text in them, but are not focused right now. Here's a demo to help you understand what I'm doing: http://www.controlstack.com/login My JS is working almost correctly (thanks to some folks on this site), except in 2 cases: If I enter something in the username field, then tab over to the password field, it does not add the ".focus" class to the password field. If I blur out of the username field, then focus back on it, enter a few characters, then delete them, it does not add the ".focus" field. Here's my code: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" dir="ltr"> <head> <title>Login</title> <style> input.field {height: 39px; width: 194px; background: url(login-fields.png) no-repeat; overflow: hidden; border: none; outline: none; float: left; margin-right: 7px;} input.field#username {padding: 0 12px;} input.field#username.focus {background-position: 0 -39px;} input.field#username.active-on {background-position: 0 -78px;} input.field#username.active-off {background-position: 0 -117px;} input.field#password {background-position: -218px 0; padding: 0 12px;} input.field#password.focus {background-position: -218px -39px;} input.field#password.active-on {background-position: -218px -78px;} input.field#password.active-off {background-position: -218px -117px;} input.field#go {background-position: -436px 0; width: 88px; margin: 0; cursor: pointer;} </style> <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script> <script type="text/javascript"> $(document).ready(function() { loginField = $('.field'); firstField = $('.field.first'); firstField.focus(); loginField.focus(function(){ loginVal1 = loginField.val(); if (!loginVal1){ $(this).removeClass('active-off').addClass('focus'); } else { $(this).removeClass('active-off').addClass('active-on'); } }); loginField.live('keydown', function(){ $(this).addClass('active-on').removeClass('active-off'); }).live('keyup', function(){ $(this).toggleClass('active-on', $(this).val() != ''); }) loginField.blur(function(){ loginVal2 = loginField.val(); if (!loginVal2){ $(this).removeClass('focus').removeClass('active-on'); $(this).val(''); } else { $(this).removeClass('focus').removeClass('active-on').addClass('active-off'); } }); }); </script> </head> <body> <h1>Login to your account</h1> <form method="post" action="/"> <fieldset> <input type="text" class="field first focus" id="username" /> <input type="text" class="field" id="password" /> <input type="submit" value="" class="field" id="go" alt="login" title="login" /> </fieldset> </form> </body> </html> Your help is much appreciated!

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  • Python/numpy tricky slicing problem

    - by daver
    Hi stack overflow, I have a problem with some numpy stuff. I need a numpy array to behave in an unusual manner by returning a slice as a view of the data I have sliced, not a copy. So heres an example of what I want to do: Say we have a simple array like this: a = array([1, 0, 0, 0]) I would like to update consecutive entries in the array (moving left to right) with the previous entry from the array, using syntax like this: a[1:] = a[0:3] This would get the following result: a = array([1, 1, 1, 1]) Or something like this: a[1:] = 2*a[:3] # a = [1,2,4,8] To illustrate further I want the following kind of behaviour: for i in range(len(a)): if i == 0 or i+1 == len(a): continue a[i+1] = a[i] Except I want the speed of numpy. The default behavior of numpy is to take a copy of the slice, so what I actually get is this: a = array([1, 1, 0, 0]) I already have this array as a subclass of the ndarray, so I can make further changes to it if need be, I just need the slice on the right hand side to be continually updated as it updates the slice on the left hand side. Am I dreaming or is this magic possible? Update: This is all because I am trying to use Gauss-Seidel iteration to solve a linear algebra problem, more or less. It is a special case involving harmonic functions, I was trying to avoid going into this because its really not necessary and likely to confuse things further, but here goes. The algorithm is this: while not converged: for i in range(len(u[:,0])): for j in range(len(u[0,:])): # skip over boundary entries, i,j == 0 or len(u) u[i,j] = 0.25*(u[i-1,j] + u[i+1,j] + u[i, j-1] + u[i,j+1]) Right? But you can do this two ways, Jacobi involves updating each element with its neighbours without considering updates you have already made until the while loop cycles, to do it in loops you would copy the array then update one array from the copied array. However Gauss-Seidel uses information you have already updated for each of the i-1 and j-1 entries, thus no need for a copy, the loop should essentially 'know' since the array has been re-evaluated after each single element update. That is to say, every time we call up an entry like u[i-1,j] or u[i,j-1] the information calculated in the previous loop will be there. I want to replace this slow and ugly nested loop situation with one nice clean line of code using numpy slicing: u[1:-1,1:-1] = 0.25(u[:-2,1:-1] + u[2:,1:-1] + u[1:-1,:-2] + u[1:-1,2:]) But the result is Jacobi iteration because when you take a slice: u[:,-2,1:-1] you copy the data, thus the slice is not aware of any updates made. Now numpy still loops right? Its not parallel its just a faster way to loop that looks like a parallel operation in python. I want to exploit this behaviour by sort of hacking numpy to return a pointer instead of a copy when I take a slice. Right? Then every time numpy loops, that slice will 'update' or really just replicate whatever happened in the update. To do this I need slices on both sides of the array to be pointers. Anyway if there is some really really clever person out there that awesome, but I've pretty much resigned myself to believing the only answer is to loop in C.

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  • ASP.NET MVC 2 "value" in IsValid override in DataAnnotation attribute passed is null, when incorrect

    - by goldenelf2
    Hello to all! This is my first question here on stack overflow. i need help on a problem i encountered during an ASP.NET MVC2 project i am currently working on. I should note that I'm relatively new to MVC design, so pls bear my ignorance. Here goes : I have a regular form on which various details about a person are shown. One of them is "Date of Birth". My view is like this <div class="form-items"> <%: Html.Label("DateOfBirth", "Date of Birth:") %> <%: Html.EditorFor(m => m.DateOfBirth) %> <%: Html.ValidationMessageFor(m => m.DateOfBirth) %> </div> I'm using an editor template i found, to show only the date correctly : <%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<System.DateTime?>"%> <%= Html.TextBox("", (Model.HasValue ? Model.Value.ToShortDateString() : string.Empty))%> I used LinqToSql designer to create my model from an sql database. In order to do some validation i made a partial class Person to extend the one created by the designer (under the same namespace) : [MetadataType(typeof(IPerson))] public partial class Person : IPerson { //To create buddy class } public interface IPerson { [Required(ErrorMessage="Please enter a name")] string Name { get; set; } [Required(ErrorMessage="Please enter a surname")] string Surname { get; set; } [Birthday] DateTime? DateOfBirth { get; set; } [Email(ErrorMessage="Please enter a valid email")] string Email { get; set; } } I want to make sure that a correct date is entered. So i created a custom DataAnnotation attribute in order to validate the date : public class BirthdayAttribute : ValidationAttribute { private const string _errorMessage = "Please enter a valid date"; public BirthdayAttribute() : base(_errorMessage) { } public override bool IsValid(object value) { if (value == null) { return true; } DateTime temp; bool result = DateTime.TryParse(value.ToString(), out temp); return result; } } Well, my problem is this. Once i enter an incorrect date in the DateOfBirth field then no custom message is displayed even if use the attribute like [Birthday(ErrorMessage=".....")]. The message displayed is the one returned from the db ie "The value '32/4/1967' is not valid for DateOfBirth.". I tried to enter some break points around the code, and found out that the "value" in attribute is always null when the date is incorrect, but always gets a value if the date is in correct format. The same ( value == null) is passed also in the code generated by the designer. This thing is driving me nuts. Please can anyone help me deal with this? Also if someone can tell me where exactly is the point of entry from the view to the database. Is it related to the model binder? because i wanted to check exactly what value is passed once i press the "submit" button. Thank you.

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  • OSX: How to get a volume name (or bsd name) from a IOUSBDeviceInterface or location id

    - by LG
    Hi, I'm trying to write an app that associates a particular USB string descriptor (of a USB mass storage device) with its volume or bsd name. So the code goes through all the connected USB devices, gets the string descriptors and extracts information from one of them. I would like to get the volume name of those USB devices. I can't find the right API to do that. I have tried to do that: DASessionRef session = DASessionCreate(kCFAllocatorDefault); DADiskRef disk_ref = DADiskCreateFromIOMedia(kCFAllocatorDefault, session, usb_device_ref); const char* name = DADiskGetBSDName(disk_ref); But the DADiskCreateFromIOMedia function returned nil, I assume the usb_device_ref that I passed was not compatible with the io_service_t that the function is expecting. So how can I get the volume name of a USB device? Could I use the location id to do that? Thanks for reading. -L FOO_Result result = FOO_SUCCESS; mach_port_t master_port; kern_return_t k_result; io_iterator_t iterator = 0; io_service_t usb_device_ref; CFMutableDictionaryRef matching_dictionary = NULL; // first create a master_port if (FOO_FAILED(k_result = IOMasterPort(MACH_PORT_NULL, &master_port))) { fprintf(stderr, "could not create master port, err = %d\n", k_result); goto cleanup; } if ((matching_dictionary = IOServiceMatching(kIOUSBDeviceClassName)) == NULL) { fprintf(stderr, "could not create matching dictionary, err = %d\n", k_result); goto cleanup; } if (FOO_FAILED(k_result = IOServiceGetMatchingServices(master_port, matching_dictionary, &iterator))) { fprintf(stderr, "could not find any matching services, err = %d\n", k_result); goto cleanup; } while (usb_device_ref = IOIteratorNext(iterator)) { IOReturn err; IOCFPlugInInterface **iodev; // requires <IOKit/IOCFPlugIn.h> IOUSBDeviceInterface **dev; SInt32 score; err = IOCreatePlugInInterfaceForService(usb_device_ref, kIOUSBDeviceUserClientTypeID, kIOCFPlugInInterfaceID, &iodev, &score); if (err || !iodev) { printf("dealWithDevice: unable to create plugin. ret = %08x, iodev = %p\n", err, iodev); return; } err = (*iodev)->QueryInterface(iodev, CFUUIDGetUUIDBytes(kIOUSBDeviceInterfaceID), (LPVOID*)&dev); (*iodev)->Release(iodev); // done with this FOO_String string_value; UInt8 string_index = 0x1; FOO_Result result = FOO_SUCCESS; CFStringRef device_name_as_cf_string; do { if (FOO_SUCCEEDED(result = FOO_GetStringDescriptor(dev, string_index, 0, string_value))) { printf("String at index %i is %s\n", string_index, string_value.GetChars()); // extract the command code if it is the FOO string if (string_value.CompareN("FOO:", 4) == 0) { FOO_Byte code = 0; FOO_HexToByte(string_value.GetChars() + 4, code); // Get other relevant information from the device io_name_t device_name; UInt32 location_id = 0; // Get the USB device's name. err = IORegistryEntryGetName(usb_device_ref, device_name); device_name_as_cf_string = CFStringCreateWithCString(kCFAllocatorDefault, device_name, kCFStringEncodingASCII); err = (*dev)->GetLocationID(dev, &location_id); // TODO: get volume or BSD name // add the device to the list break; } } string_index++; } while (FOO_SUCCEEDED(result)); err = (*dev)->USBDeviceClose(dev); if (err) { printf("dealWithDevice: error closing device - %08x\n", err); (*dev)->Release(dev); return; } err = (*dev)->Release(dev); if (err) { printf("dealWithDevice: error releasing device - %08x\n", err); return; } IOObjectRelease(usb_device_ref); // no longer need this reference }

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  • Postmortem debugging with WinDBG.

    - by Drazar
    I have an WCF-service running on an server, and occasionally(1-2 times every month) it throws an COMException with the informative message ”Unknown error (0x8005008)”. When i googled for this particular error I only got threads about problems when creating virtual directories in IIS. And the source code hasn’t anything with making a virtual directory in IIS. DirectoryServiceLib.LdapProvider.Directory - CreatePost - Could not create employee for 195001010000,000000000000: System.Runtime.InteropServices.COMException (0x80005008): Unknown error (0x80005008) at System.DirectoryServices.PropertyValueCollection.PopulateList I've taken a memorydump when I catch the Exception for further analysis in WinDBG. After switching to the right thread I executed the !CLRStack command: 000000001b8ab6d8 000000007708671a [NDirectMethodFrameStandalone: 000000001b8ab6d8] Common.MemoryDump.MiniDumpWriteDump(IntPtr, Int32, IntPtr, MINIDUMP_TYPE, IntPtr, IntPtr, IntPtr) 000000001b8ab680 000007ff002808d8 DomainBoundILStubClass.IL_STUB_PInvoke(IntPtr, Int32, IntPtr, MINIDUMP_TYPE, IntPtr, IntPtr, IntPtr) 000000001b8ab780 000007ff00280812 Common.MemoryDump.CreateMiniDump(System.String) 000000001b8ab7e0 000007ff0027b218 DirectoryServiceLib.LdapProvider.Directory.CreatePost(System.String, DirectoryServiceLib.Model.Post, DirectoryServiceLib.Model.Presumptions, Services.Common.SourceEnum, System.String) 000000001b8ad6d8 000007fef8816869 [HelperMethodFrame: 000000001b8ad6d8] 000000001b8ad820 000007feec2b6c6f System.DirectoryServices.PropertyValueCollection.PopulateList() 000000001b8ad860 000007feec225f0f System.DirectoryServices.PropertyValueCollection..ctor(System.DirectoryServices.DirectoryEntry, System.String) 000000001b8ad8a0 000007feec22d023 System.DirectoryServices.PropertyCollection.get_Item(System.String) 000000001b8ad8f0 000007ff00274d34 Common.DirectoryEntryExtension.GetStringAttribute(System.String) 000000001b8ad940 000007ff0027f507 DirectoryServiceLib.LdapProvider.DirectoryPost.Copy(DirectoryServiceLib.LdapProvider.DirectoryPost) 000000001b8ad980 000007ff0027a7cf DirectoryServiceLib.LdapProvider.Directory.CreatePost(System.String, DirectoryServiceLib.Model.Post, DirectoryServiceLib.Model.Presumptions, Services.Common.SourceEnum, System.String) 000000001b8adbe0 000007ff00279532 DirectoryServiceLib.WCFDirectory.CreatePost(System.String, DirectoryServiceLib.Model.Post, DirectoryServiceLib.Model.Presumptions, Services.Common.SourceEnum, System.String) 000000001b8adc60 000007ff001f47bd DynamicClass.SyncInvokeCreatePost(System.Object, System.Object[], System.Object[]) My conclusion is that it fails when the code is calling System.DirectoryServices.PropertyCollection.get_Item(System.String). So after issuing an !CLRStack -a I get this result: 000000001b8ad8a0 000007feec22d023 System.DirectoryServices.PropertyCollection.get_Item(System.String) PARAMETERS: this = <no data> propertyName = <no data> LOCALS: <CLR reg> = 0x0000000001dcef78 <no data> My very first question is why does it display no data on the propertyname? I am kinda new on Windbg. However I executed an dumpobject on = 0x0000000001dcef78: 0:013> !do 0x0000000001dcef78 Name: System.String MethodTable: 000007fef66d6960 EEClass: 000007fef625eec8 Size: 74(0x4a) bytes File: C:\Windows\Microsoft.Net\assembly\GAC_64\mscorlib\v4.0_4.0.0.0__b77a5c561934e089\mscorlib.dll String: personalprescriptioncode Fields: MT Field Offset Type VT Attr Value Name 000007fef66dc848 40000ed 8 System.Int32 1 instance 24 m_stringLength 000007fef66db388 40000ee c System.Char 1 instance 70 m_firstChar 000007fef66d6960 40000ef 10 System.String 0 shared static Empty >> Domain:Value 0000000000174e10:00000000019d1420 000000001a886f50:00000000019d1420 << So when the source code wants to fetch the personalprescriptioncode from Active Directory(what is used for persistence layer) it fails. Looking back at the stack it is when issuing the Copy method. DirectoryServiceLib.LdapProvider.DirectoryPost.Copy(DirectoryServiceLib.LdapProvider.DirectoryPost) So looking in the sourcecode: DirectoryPost postInLimbo = DirectoryPostFactory.Instance().GetDirectoryPost(LdapConfigReader.Instance().GetConfigValue("LimboDN"), idGenPerson.ID.UserId); if (postInLimbo != null) newPost.Copy(postInLimbo); This code is looking for another post in OU=limbo with the same UserId and if it finds one it copies the attributes to the new post. In this case it does and it fails with personalprescriptioncode. I've looked in Active Directory under OU=Limbo and the post exist there with the attribute personalprescriptioncode=31243. Question 1: Why does it display no data for some of the PARAMETERS and LOCALS? Is it the GC who has cleaned up before the memorydump had been created. Question 2: Is there anymore i can do to get to the solution to this problem?

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  • Query doesn't use a covering-index when applicable

    - by Dor
    I've downloaded the employees database and executed some queries for benchmarking purposes. Then I noticed that one query didn't use a covering index, although there was a corresponding index that I created earlier. Only when I added a FORCE INDEX clause to the query, it used a covering index. I've uploaded two files, one is the executed SQL queries and the other is the results. Can you tell why the query uses a covering-index only when a FORCE INDEX clause is added? The EXPLAIN shows that in both cases, the index dept_no_from_date_idx is being used anyway. To adapt myself to the standards of SO, I'm also writing the content of the two files here: The SQL queries: USE employees; /* Creating an index for an index-covered query */ CREATE INDEX dept_no_from_date_idx ON dept_emp (dept_no, from_date); /* Show `dept_emp` table structure, indexes and generic data */ SHOW TABLE STATUS LIKE "dept_emp"; DESCRIBE dept_emp; SHOW KEYS IN dept_emp; /* The EXPLAIN shows that the subquery doesn't use a covering-index */ EXPLAIN SELECT SQL_NO_CACHE * FROM dept_emp INNER JOIN ( /* The subquery should use a covering index, but isn't */ SELECT SQL_NO_CACHE emp_no, dept_no FROM dept_emp WHERE dept_no="d001" ORDER BY from_date DESC LIMIT 20000,50 ) AS `der` USING (`emp_no`, `dept_no`); /* The EXPLAIN shows that the subquery DOES use a covering-index, thanks to the FORCE INDEX clause */ EXPLAIN SELECT SQL_NO_CACHE * FROM dept_emp INNER JOIN ( /* The subquery use a covering index */ SELECT SQL_NO_CACHE emp_no, dept_no FROM dept_emp FORCE INDEX(dept_no_from_date_idx) WHERE dept_no="d001" ORDER BY from_date DESC LIMIT 20000,50 ) AS `der` USING (`emp_no`, `dept_no`); The results: -------------- /* Creating an index for an index-covered query */ CREATE INDEX dept_no_from_date_idx ON dept_emp (dept_no, from_date) -------------- Query OK, 331603 rows affected (33.95 sec) Records: 331603 Duplicates: 0 Warnings: 0 -------------- /* Show `dept_emp` table structure, indexes and generic data */ SHOW TABLE STATUS LIKE "dept_emp" -------------- +----------+--------+---------+------------+--------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+-------------+------------+-----------------+----------+----------------+---------+ | Name | Engine | Version | Row_format | Rows | Avg_row_length | Data_length | Max_data_length | Index_length | Data_free | Auto_increment | Create_time | Update_time | Check_time | Collation | Checksum | Create_options | Comment | +----------+--------+---------+------------+--------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+-------------+------------+-----------------+----------+----------------+---------+ | dept_emp | InnoDB | 10 | Compact | 331883 | 36 | 12075008 | 0 | 21544960 | 29360128 | NULL | 2010-05-04 13:07:49 | NULL | NULL | utf8_general_ci | NULL | | | +----------+--------+---------+------------+--------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+-------------+------------+-----------------+----------+----------------+---------+ 1 row in set (0.47 sec) -------------- DESCRIBE dept_emp -------------- +-----------+---------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-----------+---------+------+-----+---------+-------+ | emp_no | int(11) | NO | PRI | NULL | | | dept_no | char(4) | NO | PRI | NULL | | | from_date | date | NO | | NULL | | | to_date | date | NO | | NULL | | +-----------+---------+------+-----+---------+-------+ 4 rows in set (0.05 sec) -------------- SHOW KEYS IN dept_emp -------------- +----------+------------+-----------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+ | Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | +----------+------------+-----------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+ | dept_emp | 0 | PRIMARY | 1 | emp_no | A | 331883 | NULL | NULL | | BTREE | | | dept_emp | 0 | PRIMARY | 2 | dept_no | A | 331883 | NULL | NULL | | BTREE | | | dept_emp | 1 | emp_no | 1 | emp_no | A | 331883 | NULL | NULL | | BTREE | | | dept_emp | 1 | dept_no | 1 | dept_no | A | 7 | NULL | NULL | | BTREE | | | dept_emp | 1 | dept_no_from_date_idx | 1 | dept_no | A | 13 | NULL | NULL | | BTREE | | | dept_emp | 1 | dept_no_from_date_idx | 2 | from_date | A | 165941 | NULL | NULL | | BTREE | | +----------+------------+-----------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+ 6 rows in set (0.23 sec) -------------- /* The EXPLAIN shows that the subquery doesn't use a covering-index */ EXPLAIN SELECT SQL_NO_CACHE * FROM dept_emp INNER JOIN ( /* The subquery should use a covering index, but isn't */ SELECT SQL_NO_CACHE emp_no, dept_no FROM dept_emp WHERE dept_no="d001" ORDER BY from_date DESC LIMIT 20000,50 ) AS `der` USING (`emp_no`, `dept_no`) -------------- +----+-------------+------------+--------+----------------------------------------------+-----------------------+---------+------------------------+-------+-------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+------------+--------+----------------------------------------------+-----------------------+---------+------------------------+-------+-------------+ | 1 | PRIMARY | <derived2> | ALL | NULL | NULL | NULL | NULL | 50 | | | 1 | PRIMARY | dept_emp | eq_ref | PRIMARY,emp_no,dept_no,dept_no_from_date_idx | PRIMARY | 16 | der.emp_no,der.dept_no | 1 | | | 2 | DERIVED | dept_emp | ref | dept_no,dept_no_from_date_idx | dept_no_from_date_idx | 12 | | 21402 | Using where | +----+-------------+------------+--------+----------------------------------------------+-----------------------+---------+------------------------+-------+-------------+ 3 rows in set (0.09 sec) -------------- /* The EXPLAIN shows that the subquery DOES use a covering-index, thanks to the FORCE INDEX clause */ EXPLAIN SELECT SQL_NO_CACHE * FROM dept_emp INNER JOIN ( /* The subquery use a covering index */ SELECT SQL_NO_CACHE emp_no, dept_no FROM dept_emp FORCE INDEX(dept_no_from_date_idx) WHERE dept_no="d001" ORDER BY from_date DESC LIMIT 20000,50 ) AS `der` USING (`emp_no`, `dept_no`) -------------- +----+-------------+------------+--------+----------------------------------------------+-----------------------+---------+------------------------+-------+--------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+------------+--------+----------------------------------------------+-----------------------+---------+------------------------+-------+--------------------------+ | 1 | PRIMARY | <derived2> | ALL | NULL | NULL | NULL | NULL | 50 | | | 1 | PRIMARY | dept_emp | eq_ref | PRIMARY,emp_no,dept_no,dept_no_from_date_idx | PRIMARY | 16 | der.emp_no,der.dept_no | 1 | | | 2 | DERIVED | dept_emp | ref | dept_no_from_date_idx | dept_no_from_date_idx | 12 | | 37468 | Using where; Using index | +----+-------------+------------+--------+----------------------------------------------+-----------------------+---------+------------------------+-------+--------------------------+ 3 rows in set (0.05 sec) Bye

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  • Android: Use XML Layout for List Cell rather than Java Code Layout (Widgets)

    - by Stephen Finucane
    Hi, I'm in the process of making a music app and I'm currently working on the library functionality. I'm having some problems, however, in working with a list view (In particular, the cells). I'm trying to move from a simple textview layout in each cell that's created within java to one that uses an XML file for layout (Hence keeping the Java file mostly semantic) This is my original code for the cell layout: public View getView(int position, View convertView, ViewGroup parent) { String id = null; TextView tv = new TextView(mContext.getApplicationContext()); if (convertView == null) { music_column_index = musiccursor.getColumnIndexOrThrow(MediaStore.Audio.Media.TITLE); musiccursor.moveToPosition(position); id = musiccursor.getString(music_column_index); music_column_index = musiccursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DISPLAY_NAME); musiccursor.moveToPosition(position); id += "\n" + musiccursor.getString(music_column_index); music_column_index = musiccursor.getColumnIndexOrThrow(MediaStore.Audio.Albums.ALBUM); musiccursor.moveToPosition(position); id += "\n" + musiccursor.getString(music_column_index); tv.setText(id); } else tv = (TextView) convertView; return tv; } And my new version: public View getView(int position, View convertView, ViewGroup parent) { View cellLayout = findViewById(R.id.albums_list_cell); ImageView album_art = (ImageView) findViewById(R.id.album_cover); TextView album_title = (TextView) findViewById(R.id.album_title); TextView artist_title = (TextView) findViewById(R.id.artist_title); if (convertView == null) { music_column_index = musiccursor.getColumnIndexOrThrow(MediaStore.Audio.Albums.ALBUM); musiccursor.moveToPosition(position); album_title.setText(musiccursor.getString(music_column_index)); //music_column_index = musiccursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DISPLAY_NAME); //musiccursor.moveToPosition(position); music_column_index = musiccursor.getColumnIndexOrThrow(MediaStore.Audio.Media.TITLE); musiccursor.moveToPosition(position); artist_title.setText(musiccursor.getString(music_column_index)); } else{ cellLayout = (TextView) convertView; } return cellLayout; } The initialisation (done in the on create file): musiclist = (ListView) findViewById(R.id.PhoneMusicList); musiclist.setAdapter(new MusicAdapter(this)); musiclist.setOnItemClickListener(musicgridlistener); And the respective XML files: (main) <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent"> <ListView android:id="@+id/PhoneMusicList" android:layout_width="fill_parent" android:layout_height="fill_parent" /> <TextView android:id="@android:id/empty" android:layout_width="wrap_content" android:layout_height="0dip" android:layout_weight="1.0" android:text="@string/no_list_data" /> </LinearLayout> (albums_list_cell) <?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/albums_list_cell" android:layout_width="wrap_content" android:layout_height="wrap_content"> <ImageView android:id="@+id/album_cover" android:layout_alignParentLeft="true" android:layout_alignParentTop="true" android:layout_width="50dip" android:layout_height="50dip" /> <TextView android:id="@+id/album_title" android:layout_toRightOf="@+id/album_cover" android:layout_alignParentTop="true" android:layout_width="wrap_content" android:layout_height="wrap_content" /> <TextView android:id="@+id/artist_title" android:layout_toRightOf="@+id/album_cover" android:layout_below="@+id/album_title" android:layout_width="wrap_content" android:layout_height="15dip" /> </RelativeLayout> In theory (based on the tiny bit of Android I've done so far) this should work..it doesn't though. Logcat gives me a null pointer exception at line 96 of the faulty code, which is the album_title.setText line. It could be a problem with my casting but Google tells me this is ok :D Thanks for any help and let me know if you need more info!

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  • In Ruby, how to I read memory values from an external process?

    - by grg-n-sox
    So all I simply want to do is make a Ruby program that reads some values from known memory address in another process's virtual memory. Through my research and basic knowledge of hex editing a running process's x86 assembly in memory, I have found the base address and offsets for the values in memory I want. I do not want to change them; I just want to read them. I asked a developer of a memory editor how to approach this abstract of language and assuming a Windows platform. He told me the Win32API calls for OpenProcess, CreateProcess, ReadProcessMemory, and WriteProcessMemory were the way to go using either C or C++. I think that the way to go would be just using the Win32API class and mapping two instances of it; One for either OpenProcess or CreateProcess, depending on if the user already has th process running or not, and another instance will be mapped to ReadProcessMemory. I probably still need to find the function for getting the list of running processes so I know which running process is the one I want if it is running already. This would take some work to put all together, but I am figuring it wouldn't be too bad to code up. It is just a new area of programming for me since I have never worked this low level from a high level language (well, higher level than C anyways). I am just wondering of the ways to approach this. I could just use a bunch or Win32API calls, but that means having to deal with a bunch of string and array pack and unpacking that is system dependant I want to eventually make this work cross-platform since the process I am reading from is produced from an executable that has multiple platform builds, (I know the memory address changes from system to system. The idea is to have a flat file that contains all memory mappings so the Ruby program can just match the current platform environment to the matching memory mapping.) but from the looks of things I'll just have to make a class that wraps whatever is the current platform's system shared library memory related function calls. For all I know, there could already exist a Ruby gem that takes care of all of this for me that I am just not finding. I could also possibly try editing the executables for each build to make it so whenever the memory values I want to read from are written to by the process, it also writes a copy of the new value to a space in shared memory that I somehow have Ruby make an instance of a class that is a pointer under the hood to that shared memory address and somehow signal to the Ruby program that the value was updated and should be reloaded. Basically a interrupt based system would be nice, but since the purpose of reading these values is just to send to a scoreboard broadcasted from a central server, I could just stick to a polling based system that sends updates at fixed time intervals. I also could just abandon Ruby altogether and go for C or C++ but I do not know those nearly as well. I actually know more x86 than C++ and I only know C as far as system independent ANSI C and have never dealt with shared system libraries before. So is there a gem or lesser known module available that has already done this? If not, then any additional information as to how to accomplish this would be nice. I guess, long story short, how do I do all this? Thanks in advance, Grg PS: Also a confirmation that those Win32API calls should be aimed at the kernel32.dll library would be nice.

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  • skips nines in counter object, AS3

    - by VideoDnd
    It's not that noticeable at first, but my counter skips over to zero and ignores the nines. How can I get my counter to not skip over the nines? my FLA import flash.display.Sprite; import flash.events.Event; import flash.utils.Timer; import flash.events.TimerEvent; var timer:Timer; var count:int = 0; var fcount:int = 0; var numbers:NumbersView; trace("-----new NumberDocument created"); timer = new Timer(10); timer.addEventListener(TimerEvent.TIMER, incrementCounter); timer.start(); numbers = new NumbersView(); addChild(numbers); addEventListener(Event.ENTER_FRAME, enterFrameHandler); //addEventListener(Event.ADDED_TO_STAGE, traceMeOut); function incrementCounter(event:TimerEvent) { count++; fcount=int(count*count/1000); } function formatCount(i:int):String { return ("000000000" + i).substr(-9, 9); } function enterFrameHandler(e:Event):void { numbers.setTime(formatCount(fcount)); } function traceMeOut() { trace("-----Im here on stage!"); } NumbersView.as //NumbersView.as - Your Document Class package { import flash.display.MovieClip; public class NumbersView extends MovieClip { private var _listItems:Array; private const numHeight:int = 120; public function NumbersView() { _listItems = new Array(); var item:NumberImage; for (var i:Number = 0; i < 9; i++) { item = new NumberImage(); addChild(item); item.x = i * item.width; _listItems.push(item); } setTime('123456789'); } public function setTime($number:String):void { var nums:Array = $number.split(""); trace(nums); for (var i:Number = 0; i < nums.length; i++) { _listItems[i].start( int(nums[i]) ); } } } } Variation of NumbersView.as with Tweener //...SNIPPET public function setTime($number:String):void { var nums:Array = $number.split(""); for (var i:Number = 0; i < nums.length; i++) { if (nums[i] == previousNums[i]) continue; Tweener.removeTweens(_listItems[i]); var nuNum:int = int(nums[i]); var nuY:int = nuNum == 0 ? 0 : (nuNum - 1) * -numHeight; trace("nuY = " + nuY); trace("cY = " + _listItems[i].y); Tweener.addTween(_listItems[i], { y:nuY, time:0 } ); } previousNums = nums; } Variation of NumbersView.as that doesn't skip 9, but resets from bottom every count //...SNIPPET public function setTime($number:String):void { var nums:Array = $number.split(""); for (var i:Number = 0; i < nums.length; i++) { if (nums[i] == previousNums[i]) continue; Tweener.removeTweens(_listItems[i]); var newY:int = int(nums[i]) * -numHeight; if (_listItems[i].y < 0) _listItems[i].y = numHeight; Tweener.addTween(_listItems[i], { y:newY, time:3 } ); } previousNums = nums; } PUBLIC CLASS extends MovieClip place 'NumbersView.as' in same directory CLASS Library/'right-click' Properties/Class:NumberImage SYMBOL number column 70x1080 numbers 70x120 TWEENER caurina folder in local directory

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  • Running 32 bit assembly code on a 64 bit Linux & 64 bit Processor : Expalin the anomaly.

    - by claws
    Hello, I'm in an interesting problem.I forgot I'm using 64bit machine & OS and wrote a 32 bit assembly code. I don't know how to write 64 bit code. This is the x86 32-bit assembly code for Gnu Assembler (AT&T syntax) on Linux. #include <asm/unistd.h> #include <syscall.h> #define STDOUT 1 .data hellostr: .ascii "hello wolrd\n"; helloend: .text .globl _start _start: movl $(SYS_write) , %eax //ssize_t write(int fd, const void *buf, size_t count); movl $(STDOUT) , %ebx movl $hellostr , %ecx movl $(helloend-hellostr) , %edx int $0x80 movl $(SYS_exit), %eax //void _exit(int status); xorl %ebx, %ebx int $0x80 ret Now, This code should run fine on a 32bit processor & 32 bit OS right? As we know 64 bit processors are backward compatible with 32 bit processors. So, that also wouldn't be a problem. The problem arises because of differences in system calls & call mechanism in 64-bit OS & 32-bit OS. I don't know why but they changed the system call numbers between 32-bit linux & 64-bit linux. asm/unistd_32.h defines: #define __NR_write 4 #define __NR_exit 1 asm/unistd_64.h defines: #define __NR_write 1 #define __NR_exit 60 Anyway using Macros instead of direct numbers is paid off. Its ensuring correct system call numbers. when I assemble & link & run the program. Its not printing helloworld. In gdb its showing: Program exited with code 01. I don't know how to debug in gdb. using tutorial I tried to debug it and execute instruction by instruction checking registers at each step. its always showing me "program exited with 01". It would be great if some on could show me how to debug this. (gdb) break _start Note: breakpoint -10 also set at pc 0x4000b0. Breakpoint 8 at 0x4000b0 (gdb) start Function "main" not defined. Make breakpoint pending on future shared library load? (y or [n]) y Temporary breakpoint 9 (main) pending. Starting program: /home/claws/helloworld Program exited with code 01. (gdb) info breakpoints Num Type Disp Enb Address What 8 breakpoint keep y 0x00000000004000b0 <_start> 9 breakpoint del y <PENDING> main I tried running strace. This is its output: execve("./helloworld", ["./helloworld"], [/* 39 vars */]) = 0 write(0, NULL, 12 <unfinished ... exit status 1> Explain the parameters of write(0, NULL, 12) system call in the output of strace? What exactly is happening? I want to know the reason why exactly its exiting with exitstatus=1? Can some one please show me how to debug this program using gdb? Why did they change the system call numbers? Change this program appropriately so that it can run correctly on this machine.

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  • Disable antialiasing for a specific GDI device context

    - by Jacob Stanley
    I'm using a third party library to render an image to a GDI DC and I need to ensure that any text is rendered without any smoothing/antialiasing so that I can convert the image to a predefined palette with indexed colors. The third party library i'm using for rendering doesn't support this and just renders text as per the current windows settings for font rendering. They've also said that it's unlikely they'll add the ability to switch anti-aliasing off any time soon. The best work around I've found so far is to call the third party library in this way (error handling and prior settings checks ommitted for brevity): private static void SetFontSmoothing(bool enabled) { int pv = 0; SystemParametersInfo(Spi.SetFontSmoothing, enabled ? 1 : 0, ref pv, Spif.None); } // snip Graphics graphics = Graphics.FromImage(bitmap) IntPtr deviceContext = graphics.GetHdc(); SetFontSmoothing(false); thirdPartyComponent.Render(deviceContext); SetFontSmoothing(true); This obviously has a horrible effect on the operating system, other applications flicker from cleartype enabled to disabled and back every time I render the image. So the question is, does anyone know how I can alter the font rendering settings for a specific DC? Even if I could just make the changes process or thread specific instead of affecting the whole operating system, that would be a big step forward! (That would give me the option of farming this rendering out to a separate process- the results are written to disk after rendering anyway) EDIT: I'd like to add that I don't mind if the solution is more complex than just a few API calls. I'd even be happy with a solution that involved hooking system dlls if it was only about a days work. EDIT: Background Information The third-party library renders using a palette of about 70 colors. After the image (which is actually a map tile) is rendered to the DC, I convert each pixel from it's 32-bit color back to it's palette index and store the result as an 8bpp greyscale image. This is uploaded to the video card as a texture. During rendering, I re-apply the palette (also stored as a texture) with a pixel shader executing on the video card. This allows me to switch and fade between different palettes instantaneously instead of needing to regenerate all the required tiles. It takes between 10-60 seconds to generate and upload all the tiles for a typical view of the world. EDIT: Renamed GraphicsDevice to Graphics The class GraphicsDevice in the previous version of this question is actually System.Drawing.Graphics. I had renamed it (using GraphicsDevice = ...) because the code in question is in the namespace MyCompany.Graphics and the compiler wasn't able resolve it properly. EDIT: Success! I even managed to port the PatchIat function below to C# with the help of Marshal.GetFunctionPointerForDelegate. The .NET interop team really did a fantastic job! I'm now using the following syntax, where Patch is an extension method on System.Diagnostics.ProcessModule: module.Patch( "Gdi32.dll", "CreateFontIndirectA", (CreateFontIndirectA original) => font => { font->lfQuality = NONANTIALIASED_QUALITY; return original(font); }); private unsafe delegate IntPtr CreateFontIndirectA(LOGFONTA* lplf); private const int NONANTIALIASED_QUALITY = 3; [StructLayout(LayoutKind.Sequential)] private struct LOGFONTA { public int lfHeight; public int lfWidth; public int lfEscapement; public int lfOrientation; public int lfWeight; public byte lfItalic; public byte lfUnderline; public byte lfStrikeOut; public byte lfCharSet; public byte lfOutPrecision; public byte lfClipPrecision; public byte lfQuality; public byte lfPitchAndFamily; public unsafe fixed sbyte lfFaceName [32]; }

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  • Slow queries in Rails- not sure if my indexes are being used.

    - by Max Williams
    I'm doing a quite complicated find with lots of includes, which rails is splitting into a sequence of discrete queries rather than do a single big join. The queries are really slow - my dataset isn't massive, with none of the tables having more than a few thousand records. I have indexed all of the fields which are examined in the queries but i'm worried that the indexes aren't helping for some reason: i installed a plugin called "query_reviewer" which looks at the queries used to build a page, and lists problems with them. This states that indexes AREN'T being used, and it features the results of calling 'explain' on the query, which lists various problems. Here's an example find call: Question.paginate(:all, {:page=>1, :include=>[:answers, :quizzes, :subject, {:taggings=>:tag}, {:gradings=>[:age_group, :difficulty]}], :conditions=>["((questions.subject_id = ?) or (questions.subject_id = ? and tags.name = ?))", "1", 19, "English"], :order=>"subjects.name, (gradings.difficulty_id is null), gradings.age_group_id, gradings.difficulty_id", :per_page=>30}) And here are the generated sql queries: SELECT DISTINCT `questions`.id FROM `questions` LEFT OUTER JOIN `taggings` ON `taggings`.taggable_id = `questions`.id AND `taggings`.taggable_type = 'Question' LEFT OUTER JOIN `tags` ON `tags`.id = `taggings`.tag_id LEFT OUTER JOIN `subjects` ON `subjects`.id = `questions`.subject_id LEFT OUTER JOIN `gradings` ON gradings.question_id = questions.id WHERE (((questions.subject_id = '1') or (questions.subject_id = 19 and tags.name = 'English'))) ORDER BY subjects.name, (gradings.difficulty_id is null), gradings.age_group_id, gradings.difficulty_id LIMIT 0, 30 SELECT `questions`.`id` AS t0_r0 <..etc...> FROM `questions` LEFT OUTER JOIN `answers` ON answers.question_id = questions.id LEFT OUTER JOIN `quiz_questions` ON (`questions`.`id` = `quiz_questions`.`question_id`) LEFT OUTER JOIN `quizzes` ON (`quizzes`.`id` = `quiz_questions`.`quiz_id`) LEFT OUTER JOIN `subjects` ON `subjects`.id = `questions`.subject_id LEFT OUTER JOIN `taggings` ON `taggings`.taggable_id = `questions`.id AND `taggings`.taggable_type = 'Question' LEFT OUTER JOIN `tags` ON `tags`.id = `taggings`.tag_id LEFT OUTER JOIN `gradings` ON gradings.question_id = questions.id LEFT OUTER JOIN `age_groups` ON `age_groups`.id = `gradings`.age_group_id LEFT OUTER JOIN `difficulties` ON `difficulties`.id = `gradings`.difficulty_id WHERE (((questions.subject_id = '1') or (questions.subject_id = 19 and tags.name = 'English'))) AND `questions`.id IN (602, 634, 666, 698, 730, 762, 613, 645, 677, 709, 741, 592, 624, 656, 688, 720, 752, 603, 635, 667, 699, 731, 763, 614, 646, 678, 710, 742, 593, 625) ORDER BY subjects.name, (gradings.difficulty_id is null), gradings.age_group_id, gradings.difficulty_id SELECT count(DISTINCT `questions`.id) AS count_all FROM `questions` LEFT OUTER JOIN `answers` ON answers.question_id = questions.id LEFT OUTER JOIN `quiz_questions` ON (`questions`.`id` = `quiz_questions`.`question_id`) LEFT OUTER JOIN `quizzes` ON (`quizzes`.`id` = `quiz_questions`.`quiz_id`) LEFT OUTER JOIN `subjects` ON `subjects`.id = `questions`.subject_id LEFT OUTER JOIN `taggings` ON `taggings`.taggable_id = `questions`.id AND `taggings`.taggable_type = 'Question' LEFT OUTER JOIN `tags` ON `tags`.id = `taggings`.tag_id LEFT OUTER JOIN `gradings` ON gradings.question_id = questions.id LEFT OUTER JOIN `age_groups` ON `age_groups`.id = `gradings`.age_group_id LEFT OUTER JOIN `difficulties` ON `difficulties`.id = `gradings`.difficulty_id WHERE (((questions.subject_id = '1') or (questions.subject_id = 19 and tags.name = 'English'))) Actually, looking at these all nicely formatted here, there's a crazy amount of joining going on here. This can't be optimal surely. Anyway, it looks like i have two questions. 1) I have an index on each of the ids and foreign key fields referred to here. The second of the above queries is the slowest, and calling explain on it (doing it directly in mysql) gives me the following: +----+-------------+----------------+--------+---------------------------------------------------------------------------------+-------------------------------------------------+---------+------------------------------------------------+------+----------------------------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+----------------+--------+---------------------------------------------------------------------------------+-------------------------------------------------+---------+------------------------------------------------+------+----------------------------------------------+ | 1 | SIMPLE | questions | range | PRIMARY,index_questions_on_subject_id | PRIMARY | 4 | NULL | 30 | Using where; Using temporary; Using filesort | | 1 | SIMPLE | answers | ref | index_answers_on_question_id | index_answers_on_question_id | 5 | millionaire_development.questions.id | 2 | | | 1 | SIMPLE | quiz_questions | ref | index_quiz_questions_on_question_id | index_quiz_questions_on_question_id | 5 | millionaire_development.questions.id | 1 | | | 1 | SIMPLE | quizzes | eq_ref | PRIMARY | PRIMARY | 4 | millionaire_development.quiz_questions.quiz_id | 1 | | | 1 | SIMPLE | subjects | eq_ref | PRIMARY | PRIMARY | 4 | millionaire_development.questions.subject_id | 1 | | | 1 | SIMPLE | taggings | ref | index_taggings_on_taggable_id_and_taggable_type,index_taggings_on_taggable_type | index_taggings_on_taggable_id_and_taggable_type | 263 | millionaire_development.questions.id,const | 1 | | | 1 | SIMPLE | tags | eq_ref | PRIMARY | PRIMARY | 4 | millionaire_development.taggings.tag_id | 1 | Using where | | 1 | SIMPLE | gradings | ref | index_gradings_on_question_id | index_gradings_on_question_id | 5 | millionaire_development.questions.id | 2 | | | 1 | SIMPLE | age_groups | eq_ref | PRIMARY | PRIMARY | 4 | millionaire_development.gradings.age_group_id | 1 | | | 1 | SIMPLE | difficulties | eq_ref | PRIMARY | PRIMARY | 4 | millionaire_development.gradings.difficulty_id | 1 | | +----+-------------+----------------+--------+---------------------------------------------------------------------------------+-------------------------------------------------+---------+------------------------------------------------+------+----------------------------------------------+ The query_reviewer plugin has this to say about it - it lists several problems: Table questions: Using temporary table, Long key length (263), Using filesort MySQL must do an extra pass to find out how to retrieve the rows in sorted order. To resolve the query, MySQL needs to create a temporary table to hold the result. The key used for the index was rather long, potentially affecting indices in memory 2) It looks like rails isn't splitting this find up in a very optimal way. Is it, do you think? Am i better off doing several find queries manually rather than one big combined one? Grateful for any advice, max

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