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  • Recommended textbook for machine-level programming?

    - by Norman Ramsey
    I'm looking at textbooks for an undergraduate course in machine-level programming. If the perfect book existed, this is what it would look like: Uses examples written in C or assembly language, or both. Covers machine-level operations such as two's-complement integer arithmetic, bitwise operations, and floating-point arithmetic. Explains how caches work and how they affect performance. Explains machine instructions or assembly instructions. Bonus if the example assembly language includes x86; triple bonus if it includes x86-64 (aka AMD64). Explains how C values and data structures are represented using hardware registers and memory. Explains how C control structures are translated into assembly language using conditional and unconditional branch instructions. Explains something about procedure calling conventions and how procedure calls are implemented at the machine level. Books I might be interested in would probably have the words "machine organization" or "computer architecture" in the title. Here are some books I'm considering but am not quite happy with: Computer Systems: A Programmer's Perspective by Randy Bryant and Dave O'Hallaron. This is quite a nice book, but it's a book for a broad, shallow course in systems programming, and it contains a great deal of material my students don't need. Also, it is just out in a second edition, which will make it expensive. Computer Organization and Design: The Hardware/Software Interface by Dave Patterson and John Hennessy. This is also a very nice book, but it contains way more information about how the hardware works than my students need. Also, the exercises look boring. Finally, it has a show-stopping bug: it is based very heavily on MIPS hardware and the use of a MIPS simulator. My students need to learn how to use DDD, and I can't see getting this to work on a simulator. Not to mention that I can't see them cross-compiling their code for the simulator, and so on and so forth. Another flaw is that the book mentions the x86 architecture only to sneer at it. I am entirely sympathetic to this point of view, but news flash! You guys lost! Write Great Code Vol I: Understanding the Machine by Randall Hyde. I haven't evaluated this book as thoroughly as the other two. It has a lot of what I need, but the translation from high-level language to assembler is deferred to Volume Two, which has mixed reviews. My students will be annoyed if I make them buy a two-volume series, even if the price of those two volumes is smaller than the price of other books. I would really welcome other suggestions of books that would help students in a class where they are to learn how C-language data structures and code are translated to machine-level data structures and code and where they learn how to think about performance, with an emphasis on the cache.

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  • Getting a specific bit value in a byte string

    - by ignoramus
    There is a byte at a specific index in a byte string which represents eight flags; one flag per bit in the byte. If a flag is set, its corresponding bit is 1, otherwise its 0. For example, if I've got b'\x21' the flags would be 0001 0101 # Three flags are set at indexes 3, 5 and 7 # and the others are not set What would be the best way to get each bit value in that byte, so I know whether a particular flag is set or not? (Preferably using bitwise operations)

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  • ROR heroku PostGres issue

    - by oelbrenner
    getting error: ActiveRecord::StatementInvalid (PGError: ERROR: argument of HAVING must be type boolean, not type timestamp without time zone controller code snippet: def inactive @number_days = params[:days].to_i || 90 @clients = Client.find(:all, :include = :appointments, :conditions = ["clients.user_id = ? AND appointments.start_time <= ?", current_user.id, @number_days.days.ago], :group = 'client_id', :having = 'MAX(appointments.start_time)' ) end

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  • JSF inner datatable not respecting rendered condition of outer table.

    - by Marc
    <h:dataTable cellpadding="0" cellspacing="0" styleClass="list_table" id="OuterItems" value="#{valueList.values}" var="item" border="0"> <h:column rendered="#{item.typeA"> <h:dataTable cellpadding="0" cellspacing="0" styleClass="list_table" id="InnerItems" value="#{item.options}" var="option" border="0"> <h:column > <h:outputText value="Option: #{option.displayValue}"/> </h:column> </h:dataTable> </h:column> <h:column rendered="#{item.typeB"> <h:dataTable cellpadding="0" cellspacing="0" styleClass="list_table" id="InnerItems" value="#{item.demands}" var="demand" border="0"> <h:column > <h:outputText value="Demand: #{demand.displayValue}"/> </h:column> </h:dataTable> </h:column> </h:dataTable> public class Item{ ... public boolean isTypeA(){ return this instanceof TypeA; } public boolean isTypeB(){ return this instanceof TypeB; } ... } public class typeA extends Item(){ ... public List getOptions(){ .... } ... } public class typeB extends Item(){ ... public List getDemands(){ ... } .... } I'm having an issue with JSF. I've abstracted the problem out here, and I'm hoping someone can help me understand how what I'm doing fails. I'm looping over a list of Items. These Items are actually instances of the subclasses TypeA and TypeB. For Type A, I want to display the options, for Type B I want to display the demands. When rendering the page for the first time, this works fine. However, when I post back to the page for some action, I get an error: [3/26/10 12:52:32:781 EST] 0000008c SystemErr R javax.faces.FacesException: Error getting property 'options' from bean of type TypeB at com.sun.faces.lifecycle.ApplyRequestValuesPhase.execute(ApplyRequestValuesPhase.java:89) at com.sun.faces.lifecycle.LifecycleImpl.phase(LifecycleImpl.java(Compiled Code)) at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:91) at com.ibm.faces.portlet.FacesPortlet.processAction(FacesPortlet.java:193) My grasp on the JSF lifecyle is very rough. At this point, i understand there is an error in the ApplyRequestValues Phases which is very early and so the previous state is restored and nothing changes. What I don't understand is that in order to fufill the condition for rendering "item.typeA" that object has to be an instance of TypeA. But here, it looks like that object passed the condition even though it was an instance of TypeB. It is like it is evaluating the inner dataTable (InnerItems) before evaluating the outer (outerItems). My working assumption is that I just don't understand how/when the rendered attribute is actually evaluated.

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  • What is the need of collection framework in java?

    - by JavaUser
    Hi, What is the need of Collection framework in Java since all the data operations(sorting/adding/deleting) are possible with Arrays and moreover array is suitable for memory consumption and performance is also better compared with Collections. Can anyone point me a real time data oriented example which shows the difference in both(array/Collections) of these implementations. Thx

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  • NSOperation inside NSOperationQueue not being executed

    - by Martin Garcia
    I really need help here. I'm desperate at this point. I have NSOperation that when added to the NSOperationQueue is not being triggered. I added some logging to see the NSOperation status and this is the result: Queue operations count = 1 Queue isSuspended = 0 Operation isCancelled? = 0 Operation isConcurrent? = 0 Operation isFinished? = 0 Operation isExecuted? = 0 Operation isReady? = 1 Operation dependencies? = 0 The code is very simple. Nothing special. LoadingConflictEvents_iPad *loadingEvents = [[LoadingConflictEvents_iPad alloc] initWithNibName:@"LoadingConflictEvents_iPad" bundle:[NSBundle mainBundle]]; loadingEvents.modalPresentationStyle = UIModalPresentationFormSheet; loadingEvents.conflictOpDelegate = self; [self presentModalViewController:loadingEvents animated:NO]; [loadingEvents release]; ConflictEventOperation *operation = [[ConflictEventOperation alloc] initWithParameters:wiLr.formNumber pWI_ID:wiLr.wi_id]; [queue addOperation:operation]; NSLog(@"Queue operations count = %d",[queue operationCount]); NSLog(@"Queue isSuspended = %d",[queue isSuspended]); NSLog(@"Operation isCancelled? = %d",[operation isCancelled]); NSLog(@"Operation isConcurrent? = %d",[operation isConcurrent]); NSLog(@"Operation isFinished? = %d",[operation isFinished]); NSLog(@"Operation isExecuted? = %d",[operation isExecuting]); NSLog(@"Operation isReady? = %d",[operation isReady]); NSLog(@"Operation dependencies? = %d",[[operation dependencies] count]); [operation release]; Now my operation do many things on the main method, but the problem is never being called. The main is never executed. The most weird thing (believe me, I'm not crazy .. yet). If I put a break point in any NSLog line or in the creation of the operation the main method will be called and everything will work perfectly. This have been working fine for a long time. I have been making some changes recently and apparently something screw things up. One of those changes was to upgrade the device to iOS 5.1 SDK (iPad). To add something, I have the iPhone (iOS 5.1) version of this application that use the same NSOperation object. The difference is in the UI only, and everything works fine. Any help will be really appreciated. Regards,

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  • What is the best way, if possible, to send information from a Java PrintStream to a JTextPane?

    - by Daniel Reeves
    In Java, I have a package that translates XML metadata from one standard to another. This package is ultimately accessed through a single function and sends all of its output through a PrintStream object. The output sent is just a status of each file and whether or not it was translated. This is pretty fine and dandy if I'm just printing to System.out, but I'm actually wanting to print this to a JTextPane while it translates (kind of like a progress text box). It wouldn't be a big deal to just print the status after it was done translating the XML, but since there may be thousands of XML files, that's just not feasible. One thing that I've tried is to use a thread that takes all of the information from the PrintStream (which is attached to a ByteArrayOutputStream) and let it send any new information to the text pane. Unfortunately, this still sends the information all at once at the end of the translation. This does work correctly for System.out. Here's the code that does the translation and tries to show the output: public class ConverterGUI extends javax.swing.JFrame { boolean printToResultsBox = false; PrintStream printStream = null; ByteArrayOutputStream baos = null; private class ResultsPrinter implements Runnable { public ResultsPrinter() { baos = new ByteArrayOutputStream(); printStream = new PrintStream(baos); } public void run() { String tempString = ""; while (printToResultsBox) { try { if (!baos.toString().equals(tempString)) { tempString = baos.toString(); resultsBox.setText(tempString); } } catch (Exception ex) { } } } } ... ResultsPrinter rp = new ResultsPrinter(); Thread thread = new Thread(rp); thread.start(); // Do the translation. try { printToResultsBox = true; boolean success = false; TranslationEngine te = new TranslationEngine(); // fileOrFolderToConvert is a text box in the GUI. // linkNeeded and destinationFile are just parameters for the translation process. success = te.translate(fileOrFolderToConvert.getText(), linkNeeded, destinationFile, printStream); if (success) { printStream.println("File/folder translation was a success."); } resultsBox.setText(baos.toString()); } catch (Exception ex) { printStream.println("File translation failed."); } finally { printToResultsBox = false; } ... } Ultimately, this code prints out to the JTextPane just fine after all the translation is done but not during. Any suggestions? Do I need to change the PrintStream to something else?

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  • How to output JOINed tables?

    - by ilhan
    $id=(int)$_GET["id"]; $result = mysql_query("SELECT questionstable.*, categorytable.name FROM questionstable INNER JOIN categorytable ON categorytable.id = questionstable.category WHERE id=$id"); $row = mysql_fetch_assoc($result); Warning: mysql_fetch_assoc() expects parameter 1 to be resource, boolean given in C:\Program Files\EasyPHP-5.3.4.0\www\scsoru.php on line 33

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  • Python vs. Java performance (runtime speed)

    - by Bijan
    Ignoring all the characteristics of each languages and focusing SOLELY on speed, which language is better performance-wise? You'd think this would be a rather simple question to answer, but I haven't found a decent one. I'm aware that some types of operations may be faster with python, and vice-versa, but I cannot find any detailed information on this. Can anyone shed some light on the performance differences?

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  • java filenames filter pattern

    - by Sergey
    Hello, I need to implement File[] files = getFiles( String folderName, String ptrn ); Where ptrn is a command prompt style pattern like "*2010*.txt" I'm familar with FilenameFilter class, but can't implement public boolean accept(File dir, String filename) because String.matches() doesn't accept such patterns. Thanks!

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  • Understanding Haskell's filter

    - by dmindreader
    I understand that Haskell's filter is a high order function (meaning a function that takes another function as a parameter) that goes through a list checking which element fulfills certain boolean condition. I don't quite understand its definition: filter:: (a->Bool)->[a]->[a] filter p [] = [] filter p (x:y) | p x = x:filter p y | otherwise = filter p y I understand that if I pass an empty list to the function, it would just return an empty list, but how do I read the last two lines?

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  • High speed matrix manipulation in c#?

    - by Donnie
    I'm working on some image manipulation code in c# and need to do some matrix operations (specifically 2D convolution). I have the code written in matlab which uses the conv2 function ... is there a library for C# / .NET that does good high-speed matrix manipulations? I'd be fine if it requires some specific GPU and does the matrix math on-GPU if that's what it takes.

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  • Broadcast receiver, check status, turning off connection with F8

    - by yoann
    I am using eclipse with android sdk 3.2 I have some problems to make my broadcast receiver working when the connection is lost. first I have checked the type of network to make sure I understand well : ConnectivityManager manager = (ConnectivityManager) getSystemService(CONNECTIVITY_SERVICE); boolean is3g = manager.getNetworkInfo( ConnectivityManager.TYPE_MOBILE) .isConnectedOrConnecting(); boolean isWifi = manager.getNetworkInfo( ConnectivityManager.TYPE_WIFI) .isConnectedOrConnecting(); NetworkInfo info = manager.getActiveNetworkInfo(); if (info != null) Toast.makeText(getApplicationContext(), info.getTypeName(), Toast.LENGTH_LONG).show(); else Toast.makeText(getApplicationContext(), "Pas de connexion", Toast.LENGTH_LONG).show(); if (!is3g) Log.i("Network Listener", "DISCONNECTED"); else Log.i("Network Listener", "CONNECTED"); == this is a mobile network, I'm connected Then I press F8 or I make : telnet localhost 5554 gsm data off to stop the connection Here is my dynamic broadcast receiver in an activity : public class ActivityA extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.query); this.registerReceiver(this.networkStateReceiver, new IntentFilter( ConnectivityManager.CONNECTIVITY_ACTION)); } BroadcastReceiver networkStateReceiver = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { ConnectivityManager connMgr = (ConnectivityManager) context .getSystemService(Context.CONNECTIVITY_SERVICE); NetworkInfo networkInfo = connMgr.getActiveNetworkInfo(); //i have tried several things : State networkState = networkInfo.getState(); // if (networkState.compareTo(State.DISCONNECTED) == 0) ... if (networkInfo != null && networkInfo.isConnected()) { Toast.makeText(getApplicationContext(), "CONNECTED", Toast.LENGTH_LONG).show(); Log.i("Network Listener", "Connected"); } else { Toast.makeText(getApplicationContext(), "DISCONNECTED", Toast.LENGTH_LONG).show(); Log.i("Network Listener", "Network Type Changed"); Intent offline = new Intent(AccountInfoActivity.this, OfflineWorkService.class); startService(offline); } }; My manifest : <uses-permission android:name="android.permission.INTERNET" /> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/> The problem is : when the activityA is launched, my broadcast receive something and it displays "Connected"(Log) and my toast. When I turn off the connection manually, nothing happend. My service is not started, log message are not displayed, only toast messages work ... And even better, when I turn on the connection again (by pressing F8), I test again the type of connection, Toast messages are shown but this time Log messages don't work. Problems happend when I press F8. Anyway, I think I miss something with broadcast receivers, it's not totally clear. Please help me.

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  • Android Couchdb - libcouch and IPC Aidl Services

    - by dirtySanchez
    I am working on a native CouchdDB app with android. Now just this week CouchOne released libcouch, described as "Library files needed to interact with CouchDB on Android": couchone_libcouch@Github It is a basic app that installs CouchDB if the CouchDB service (that comes with CouchDB if it was installed previously) can't be bound to. To be more precise, as I understand it: libcouch estimates CouchDb's presence on the device by trying to bind to a IPC Service from CouchDB and through that service wants communicate with CouchDB. Please see the method "attemptLaunch()" at CouchAppLauncher.class for reviewing this: public void attemptLaunch() { Log.i(TAG,"1.) called attemptLaunch"); Intent intent = new Intent(ICouchService.class.getName()); Log.i(TAG,"1.a) setup Intent"); Boolean canStart = bindService(intent, couchServiceConn, Context.BIND_AUTO_CREATE); Log.i(TAG,"1.b bound service. canStart: " + Boolean.toString(canStart)); if (!canStart) { setContentView(R.layout.install_couchdb); TextView label = (TextView) findViewById(R.id.install_couchdb_text); Button btn = (Button) this.findViewById(R.id.install_couchdb_btn); String text = getString(R.string.app_name) + " requires Apache CouchDB to be installed."; label.setText(text); // Launching the market will fail on emulators btn.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { launchMarket(); finish(); } }); } } The question(s) I have about this are: libcouch never is able to "find" a previously installed CouchDB. It always attempts to install CouchDB from the market. This is because it never actually is able to bind to the CouchDBService. As I understand the purpose auf AIDL generated service interfaces, the actual service that intends to offer it's IPC to other applications should make use of AIDL. In this case the AIDL has been moved to the application that is trying to bind to the remote service, which is libcouch in this case. Reviewing the commits the AIDL files have just been moved out of that repository to libcouch. For complete linkage, here's the link to the Android CouchDB sources: github.com/couchone/libcouch-android Now, I could be completely wrong in my findings, it could also be lincouch's Manifest that s missing something, but I am really looking forward to get some answers!

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  • Built-in precedence for Expression Trees?

    - by jdk
    I'm unable to find the .NET FCL built-in concept of precedence to leverage while constructing Expression Trees. Ref System.Linq.Expressions Namespace. Is this something that must be handled manually in code, or is it somehow implicit and I'm not recognizing it, maybe through helper methods or classes? I want to apply it to math operations to ensure 3 + 5 * 10 results in 53 instead of 80.

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  • How do I use an Entity Framework 4 model without a real database?

    - by Ivan
    I don't need any data to be stored. I'd like an application to start, create an Entity Framework entities container based on the model I've designed but having no data records in it, then generate some data (from user input and other input sources), work with it and discard all the data on close, without propagating any data operations made with EF contect to a real database hosted on server or in a file. How do I implement such a pattern? I use Entity Framework 4 and Visual Studio 2010.

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  • Overriding or overloading?

    - by atch
    Guys I know this question is silly but just to make sure: Having in my class method: boolean equal(Document d) { //do something } I'm overloading this method nor overriding right? I know that this or similiar question will be on upcoming egzam and would be stupid to not get points for such a simple mistake;

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  • implement bank using python programming

    - by prajakta
    Write software for a bank. The program should be menu driven with the facility for bank employees to perform various operations. It should be written using all concepts of Object Oriented programming. You should be able to save your data in a file and read it back (because the bank people will shut down their computers when they go home :p ) Guidelines: The program may select to implement classes like Bank, Account, Savings Account, Fixed Deposit account, Customer, Depositor, Borrower, Transaction, etc.

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  • Asp.Net Mvc - Html.TextBox - Set Autofocus property

    - by Melursus
    In Html 5, there is an new attribute on textbox call autofocus. The problem is it is a boolean value (there or not there) It should look something like : <input name="a" value="" autofocus> I try : <%= Html.TextBox( "a", null, new { autofocus } ) %> But, it's give me an error because I'm not setting a value to autofocus... I know I can do it manually, but can I do it with Html.TextBox ?

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  • get Phone numbers from android phone

    - by Luca
    Hi! First of all i'm sorry for my english... I've a problem getting phone numbers from contacts. That's my code import android.app.ListActivity; import android.database.Cursor; import android.os.Bundle; import android.provider.ContactsContract; import android.widget.SimpleAdapter; import android.widget.Toast; import java.util.ArrayList; import java.util.HashMap; public class TestContacts extends ListActivity { private ArrayList<HashMap<String,String>> list = new ArrayList<HashMap<String,String>>(); private SimpleAdapter numbers; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.contacts); numbers = new SimpleAdapter( this, list, R.layout.main_item_two_line_row, new String[] { "line1","line2" }, new int[] { R.id.text1, R.id.text2 } ); setListAdapter( numbers ); Cursor cursor = getContentResolver().query(ContactsContract.Contacts.CONTENT_URI, null, null, null, null); while (cursor.moveToNext()) { String contactId = cursor.getString(cursor.getColumnIndex( ContactsContract.Contacts._ID)); String hasPhone = cursor.getString(cursor.getColumnIndex( ContactsContract.Contacts.HAS_PHONE_NUMBER)); //check if the contact has a phone number if (Boolean.parseBoolean(hasPhone)) { Cursor phones = getContentResolver().query( ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null, ContactsContract.CommonDataKinds.Phone.CONTACT_ID +" = "+ contactId, null, null); while (phones.moveToNext()) { // Get the phone number!? String contactName = phones.getString( phones.getColumnIndex( ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME)); String phoneNumber = phones.getString( phones.getColumnIndex( ContactsContract.CommonDataKinds.Phone.NUMBER)); Toast.makeText(this, phoneNumber, Toast.LENGTH_LONG).show(); drawContact(contactName, phoneNumber); } phones.close(); } }cursor.close(); } private void drawContact(String name, String number){ HashMap<String,String> item = new HashMap<String,String>(); item.put( "line1",name); item.put( "line2",number); list.add( item ); numbers.notifyDataSetChanged(); } } It'seems that no contact have a phone number (i've added 2 contacts on the emulator and i've tried also on my HTC Desire). The problem is that if (Boolean.parseBoolean(hasPhone)) returns always false.. How can i get correctly phone numbers? I've tried to call drawContact(String name, String number) before the if statement without querying for the phone number, and it worked (it draws two times the name). but on the LinearLayout they are not ordered alphabetically... how can i order alphabetically (similar to the original contacts app)? thank you in advice, Luca

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