Search Results

Search found 6177 results on 248 pages for 'reputation points'.

Page 237/248 | < Previous Page | 233 234 235 236 237 238 239 240 241 242 243 244  | Next Page >

• How can a single disk in a hardware SATA RAID-10 array bring the entire array to a screeching halt?

  - by Stu Thompson

  Prelude: I'm a code-monkey that's increasingly taken on SysAdmin duties for my small company. My code is our product, and increasingly we provide the same app as SaaS. About 18 months ago I moved our servers from a premium hosting centric vendor to a barebones rack pusher in a tier IV data center. (Literally across the street.) This ment doing much more ourselves--things like networking, storage and monitoring. As part the big move, to replace our leased direct attached storage from the hosting company, I built a 9TB two-node NAS based on SuperMicro chassises, 3ware RAID cards, Ubuntu 10.04, two dozen SATA disks, DRBD and . It's all lovingly documented in three blog posts: Building up & testing a new 9TB SATA RAID10 NFSv4 NAS: Part I, Part II and Part III. We also setup a Cacit monitoring system. Recently we've been adding more and more data points, like SMART values. I could not have done all this without the awesome boffins at ServerFault. It's been a fun and educational experience. My boss is happy (we saved bucket loads of $$$), our customers are happy (storage costs are down), I'm happy (fun, fun, fun). Until yesterday. Outage & Recovery: Some time after lunch we started getting reports of sluggish performance from our application, an on-demand streaming media CMS. About the same time our Cacti monitoring system sent a blizzard of emails. One of the more telling alerts was a graph of iostat await. Performance became so degraded that Pingdom began sending "server down" notifications. The overall load was moderate, there was not traffic spike. After logging onto the application servers, NFS clients of the NAS, I confirmed that just about everything was experiencing highly intermittent and insanely long IO wait times. And once I hopped onto the primary NAS node itself, the same delays were evident when trying to navigate the problem array's file system. Time to fail over, that went well. Within 20 minuts everything was confirmed to be back up and running perfectly. Post-Mortem: After any and all system failures I perform a post-mortem to determine the cause of the failure. First thing I did was ssh back into the box and start reviewing logs. It was offline, completely. Time for a trip to the data center. Hardware reset, backup an and running. In /var/syslog I found this scary looking entry: Nov 15 06:49:44 umbilo smartd[2827]: Device: /dev/twa0 [3ware_disk_00], 6 Currently unreadable (pending) sectors Nov 15 06:49:44 umbilo smartd[2827]: Device: /dev/twa0 [3ware_disk_07], SMART Prefailure Attribute: 1 Raw_Read_Error_Rate changed from 171 to 170 Nov 15 06:49:45 umbilo smartd[2827]: Device: /dev/twa0 [3ware_disk_10], 16 Currently unreadable (pending) sectors Nov 15 06:49:45 umbilo smartd[2827]: Device: /dev/twa0 [3ware_disk_10], 4 Offline uncorrectable sectors Nov 15 06:49:45 umbilo smartd[2827]: Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_error Nov 15 06:49:45 umbilo smartd[2827]: # 1 Short offline Completed: read failure 90% 6576 3421766910 Nov 15 06:49:45 umbilo smartd[2827]: # 2 Short offline Completed: read failure 90% 6087 3421766910 Nov 15 06:49:45 umbilo smartd[2827]: # 3 Short offline Completed: read failure 10% 5901 656821791 Nov 15 06:49:45 umbilo smartd[2827]: # 4 Short offline Completed: read failure 90% 5818 651637856 Nov 15 06:49:45 umbilo smartd[2827]: So I went to check the Cacti graphs for the disks in the array. Here we see that, yes, disk 7 is slipping away just like syslog says it is. But we also see that disk 8's SMART Read Erros are fluctuating. There are no messages about disk 8 in syslog. More interesting is that the fluctuating values for disk 8 directly correlate to the high IO wait times! My interpretation is that: Disk 8 is experiencing an odd hardware fault that results in intermittent long operation times. Somehow this fault condition on the disk is locking up the entire array Maybe there is a more accurate or correct description, but the net result has been that the one disk is impacting the performance of the whole array. The Question(s) How can a single disk in a hardware SATA RAID-10 array bring the entire array to a screeching halt? Am I being naïve to think that the RAID card should have dealt with this? How can I prevent a single misbehaving disk from impacting the entire array? Am I missing something?

  Read the article

• Lockless queue implementation ends up having a loop under stress

  - by Fozi

  I have lockless queues written in C in form of a linked list that contains requests from several threads posted to and handled in a single thread. After a few hours of stress I end up having the last request's next pointer pointing to itself, which creates an endless loop and locks up the handling thread. The application runs (and fails) on both Linux and Windows. I'm debugging on Windows, where my COMPARE_EXCHANGE_PTR maps to InterlockedCompareExchangePointer. This is the code that pushes a request to the head of the list, and is called from several threads: void push_request(struct request * volatile * root, struct request * request) { assert(request); do { request->next = *root; } while(COMPARE_EXCHANGE_PTR(root, request, request->next) != request->next); } This is the code that gets a request from the end of the list, and is only called by a single thread that is handling them: struct request * pop_request(struct request * volatile * root) { struct request * volatile * p; struct request * request; do { p = root; while(*p && (*p)->next) p = &(*p)->next; // <- loops here request = *p; } while(COMPARE_EXCHANGE_PTR(p, NULL, request) != request); assert(request->next == NULL); return request; } Note that I'm not using a tail pointer because I wanted to avoid the complication of having to deal with the tail pointer in push_request. However I suspect that the problem might be in the way I find the end of the list. There are several places that push a request into the queue, but they all look generaly like this: // device->requests is defined as struct request * volatile requests; struct request * request = malloc(sizeof(struct request)); if(request) { // fill out request fields push_request(&device->requests, request); sem_post(device->request_sem); } The code that handles the request is doing more than that, but in essence does this in a loop: if(sem_wait_timeout(device->request_sem, timeout) == sem_success) { struct request * request = pop_request(&device->requests); // handle request free(request); } I also just added a function that is checking the list for duplicates before and after each operation, but I'm afraid that this check will change the timing so that I will never encounter the point where it fails. (I'm waiting for it to break as I'm writing this.) When I break the hanging program the handler thread loops in pop_request at the marked position. I have a valid list of one or more requests and the last one's next pointer points to itself. The request queues are usually short, I've never seen more then 10, and only 1 and 3 the two times I could take a look at this failure in the debugger. I thought this through as much as I could and I came to the conclusion that I should never be able to end up with a loop in my list unless I push the same request twice. I'm quite sure that this never happens. I'm also fairly sure (although not completely) that it's not the ABA problem. I know that I might pop more than one request at the same time, but I believe this is irrelevant here, and I've never seen it happening. (I'll fix this as well) I thought long and hard about how I can break my function, but I don't see a way to end up with a loop. So the question is: Can someone see a way how this can break? Can someone prove that this can not? Eventually I will solve this (maybe by using a tail pointer or some other solution - locking would be a problem because the threads that post should not be locked, I do have a RW lock at hand though) but I would like to make sure that changing the list actually solves my problem (as opposed to makes it just less likely because of different timing).

  Read the article

• Android Alert Dialog Extract User Choice Radio Button?

  - by kel196

  Apologies for any coding ignorance, I am a beginner and am still learning! I am creating a quiz app which reads questions off a SQL database and plots them as points on a google map. As the user clicks each point, an alert dialog appears with radio buttons to answer some question. My radiobuttons are in CustomItemizedOverlay file and when I click submit, I want to be able to send the user choice back to the database, save it and return to the user if their answer is correct. My question is this, how do I pass the user choice out once the submit button has been clicked? I tried making a global variable to read what was selected to no avail. Any suggestions would be appreciated! If I need to post any other code, please ask and I will do so ASAP! package uk.ac.ucl.cege.cegeg077.uceskkw; import java.util.ArrayList; import android.app.AlertDialog; import android.content.Context; import android.content.DialogInterface; import android.graphics.drawable.Drawable; import android.widget.Toast; import com.google.android.maps.ItemizedOverlay; import com.google.android.maps.OverlayItem; public class CustomItemizedOverlay2 extends ItemizedOverlay<OverlayItem> { private ArrayList<OverlayItem> mapOverlays = new ArrayList<OverlayItem>(); private Context context; public CustomItemizedOverlay2(Drawable defaultMarker) { super(boundCenterBottom(defaultMarker)); } public CustomItemizedOverlay2(Drawable defaultMarker, Context context) { this(defaultMarker); this.context = context; } @Override protected OverlayItem createItem(int i) { return mapOverlays.get(i); } @Override public int size() { return mapOverlays.size(); } @Override protected boolean onTap(int index) { OverlayItem item = mapOverlays.get(index); // gets the snippet from ParseKMLAndDisplayOnMap and splits it back into // a string. final CharSequence allanswers[] = item.getSnippet().split("::"); AlertDialog.Builder dialog = new AlertDialog.Builder(context); dialog.setIcon(R.drawable.easterbunnyegg); dialog.setTitle(item.getTitle()); dialog.setSingleChoiceItems(allanswers, -1, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int whichButton) { Toast.makeText(context, "You have selected " + allanswers[whichButton], Toast.LENGTH_SHORT).show(); } }); dialog.setPositiveButton(R.string.button_submit, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int whichButton) { dialog.dismiss(); // int selectedPosition = ((AlertDialog) // dialog).getListView().getCheckedItemPosition(); Toast.makeText(context, "hi!", Toast.LENGTH_SHORT) .show(); } }); dialog.setNegativeButton(R.string.button_close, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int whichButton) { dialog.dismiss(); // on cancel button action } }); AlertDialog question = dialog.create(); question.show(); return true; } public void addOverlay(OverlayItem overlay) { mapOverlays.add(overlay); this.populate(); } }

  Read the article

• How to draw complex shape from code behind for custom control in resource dictionary

  - by HopelessCoder

  Hi I am new to wpf and am having a problem which may or may not be trivial. I have defined a custom control as follows in the resource dictionary: <ResourceDictionary x:Class="SyringeSlider.Themes.Generic" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="clr-namespace:SyringeSlider"> <Style TargetType="{x:Type local:CustomControl1}"> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="{x:Type local:CustomControl1}"> <Border Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}"> <Canvas Height="{TemplateBinding Height}" Width="{TemplateBinding Width}" Name="syringeCanvas"> </Canvas> </Border> </ControlTemplate> </Setter.Value> </Setter> </Style> </ResourceDictionary> Unfortunately I cannot go beyond this because I would like to draw a geometry onto the canvas consisting of a set of multiple line geometries whose dimensions are calculated as a function of the space available in the canvas. I believe that I need a code behind method to do this, but have not been able to determine how to link the xaml definition to a code behind method. Note that I have set up a class x:Class="SyringeSlider.Themes.Generic" for specifically this purpose, but can't figure out which Canvas property to link the drawing method to. My drawing method looks like this private void CalculateSyringe() { int adjHeight = (int) Height - 1; int adjWidth = (int) Width - 1; // Calculate some very useful values based on the chart above. int borderOffset = (int)Math.Floor(m_borderWidth / 2.0f); int flangeLength = (int)(adjHeight * .05f); int barrelLeftCol = (int)(adjWidth * .10f); int barrelLength = (int)(adjHeight * .80); int barrelRightCol = adjWidth - barrelLeftCol; int coneLength = (int)(adjHeight * .10); int tipLeftCol = (int)(adjWidth * .45); int tipRightCol = adjWidth - tipLeftCol; int tipBotCol = adjWidth - borderOffset; Path mySyringePath = new Path(); PathGeometry mySyringeGeometry = new PathGeometry(); PathFigure mySyringeFigure = new PathFigure(); mySyringeFigure.StartPoint = new Point(0, 0); Point pointA = new Point(0, flangeLength); mySyringeFigure.Segments.Add(new LineSegment(pointA, true)); Point pointB = new Point(); pointB.Y = pointA.Y + barrelLength; pointB.X = 0; mySyringeFigure.Segments.Add(new LineSegment(pointB, true)); // You get the idea....Add more points in this way mySyringeGeometry.Figures.Add(mySyringeFigure); mySyringePath.Data = mySyringeGeometry; } SO my question is: 1) Does what I am trying to do make any sense? 2) Can a use a canvas for this purpose? If not, what are my other options? Thanks!

  Read the article

• Roguelike FOV problem

  - by Manderin87

  I am working on a college compsci project and I would like some help with a field of view algorithm. I works mostly, but in some situations the algorithm sees through walls and hilights walls the player should not be able to see. void cMap::los(int x0, int y0, int radius) { //Does line of sight from any particular tile for(int x = 0; x < m_Height; x++) { for(int y = 0; y < m_Width; y++) { getTile(x,y)->setVisible(false); } } double xdif = 0; double ydif = 0; bool visible = false; float dist = 0; for (int x = MAX(x0 - radius,0); x < MIN(x0 + radius, m_Height); x++) { //Loops through x values within view radius for (int y = MAX(y0 - radius,0); y < MIN(y0 + radius, m_Width); y++) { //Loops through y values within view radius xdif = pow( (double) x - x0, 2); ydif = pow( (double) y - y0, 2); dist = (float) sqrt(xdif + ydif); //Gets the distance between the two points if (dist <= radius) { //If the tile is within view distance, visible = line(x0, y0, x, y); //check if it can be seen. if (visible) { //If it can be seen, getTile(x,y)->setVisible(true); //Mark that tile as viewable } } } } } bool cMap::line(int x0,int y0,int x1,int y1) { bool steep = abs(y1-y0) > abs(x1-x0); if (steep) { swap(x0, y0); swap(x1, y1); } if (x0 > x1) { swap(x0,x1); swap(y0,y1); } int deltax = x1-x0; int deltay = abs(y1-y0); int error = deltax/2; int ystep; int y = y0; if (y0 < y1) ystep = 1; else ystep = -1; for (int x = x0; x < x1; x++) { if ( steep && getTile(y,x)->isBlocked()) { getTile(y,x)->setVisible(true); getTile(y,x)->setDiscovered(true); return false; } else if (!steep && getTile(x,y)->isBlocked()) { getTile(x,y)->setVisible(true); getTile(x,y)->setDiscovered(true); return false; } error -= deltay; if (error < 0) { y = y + ystep; error = error + deltax; } } return true; } If anyone could help me make the first blocked tiles visible but stops the rest, I would appreciate it. thanks, Manderin87

  Read the article

• Getting Segmentation Fault in C++, but why?

  - by Carlos

  I am getting segmentation fault in this code but i cant figure out why. I know a segmentation fault happens when a pointer is NULL, or when it points to a random memory address. #include <iostream> #include <fstream> #include <cmath> using namespace std; //**************************** CLASS ******************************* class Database { struct data{ string city; float latitude, longitude; data *link; }*p; public: Database(); void display(); void add(string cityName, float lat, float lon); private: string cityName; float lat, lon; }; //************************** CLASS METHODS ************************** Database::Database() { p = NULL; } void Database::add(string cityName, float lat, float lon){ data *q, *t; if(p == NULL){ p = new data; p -> city = cityName; p -> latitude = lat; p -> longitude = lon; p -> link = NULL; } else{ q = p; while(q -> link != NULL){ q = q -> link; } t = new data; t -> city = cityName; t -> latitude = lat; t -> longitude = lon; q -> link = t; } } void Database::display() { data *q; cout<<endl; for( q = p ; q != NULL ; q = q->link ) cout << endl << q -> city; } //***************************** MAIN ******************************* //*** INITIALIZATION *** Database D; void loadDatabase(); //****** VARIABLES ***** //******* PROGRAM ****** int main() { loadDatabase(); D.display(); } void loadDatabase() { int i = 0; string cityName; float lat, lon; fstream city; city.open("city.txt", ios::in); fstream latitude; latitude.open("lat.txt", ios::in); fstream longitude; longitude.open("lon.txt", ios::in); while(!city.eof()){ //************************************ city >> cityName; //* * latitude >> lat; //Here is where i think is the problem longitude >> lon; //* * D.add(cityName, lat, lon); //************************************ } city.close(); latitude.close(); longitude.close(); } This is the error am actually getting in console

  Read the article

• iPhone multi-touch scale and rotate, how to prevent scale?

  - by russhill

  I have existing code for tracking multi-touch positions and then rotating and scaling the item - in this case an image - appropriately. The code works really well and in itself is perfect, however for this particular task, I need the rotation ONLY. I have spent time trying to work out what is going on in this routine, but maths is not my strong point so wanted to see if anyone could assist? - (CGAffineTransform)incrementalTransformWithTouches:(NSSet *)touches { NSArray *sortedTouches = [[touches allObjects] sortedArrayUsingSelector:@selector(compareAddress:)]; NSInteger numTouches = [sortedTouches count]; // No touches if (numTouches == 0) { return CGAffineTransformIdentity; } // Single touch if (numTouches == 1) { UITouch *touch = [sortedTouches objectAtIndex:0]; CGPoint beginPoint = *(CGPoint *)CFDictionaryGetValue(touchBeginPoints, touch); CGPoint currentPoint = [touch locationInView:self.superview]; return CGAffineTransformMakeTranslation(currentPoint.x - beginPoint.x, currentPoint.y - beginPoint.y); } // If two or more touches, go with the first two (sorted by address) UITouch *touch1 = [sortedTouches objectAtIndex:0]; UITouch *touch2 = [sortedTouches objectAtIndex:1]; CGPoint beginPoint1 = *(CGPoint *)CFDictionaryGetValue(touchBeginPoints, touch1); CGPoint currentPoint1 = [touch1 locationInView:self.superview]; CGPoint beginPoint2 = *(CGPoint *)CFDictionaryGetValue(touchBeginPoints, touch2); CGPoint currentPoint2 = [touch2 locationInView:self.superview]; double layerX = self.center.x; double layerY = self.center.y; double x1 = beginPoint1.x - layerX; double y1 = beginPoint1.y - layerY; double x2 = beginPoint2.x - layerX; double y2 = beginPoint2.y - layerY; double x3 = currentPoint1.x - layerX; double y3 = currentPoint1.y - layerY; double x4 = currentPoint2.x - layerX; double y4 = currentPoint2.y - layerY; // Solve the system: // [a b t1, -b a t2, 0 0 1] * [x1, y1, 1] = [x3, y3, 1] // [a b t1, -b a t2, 0 0 1] * [x2, y2, 1] = [x4, y4, 1] double D = (y1-y2)*(y1-y2) + (x1-x2)*(x1-x2); if (D < 0.1) { return CGAffineTransformMakeTranslation(x3-x1, y3-y1); } double a = (y1-y2)*(y3-y4) + (x1-x2)*(x3-x4); double b = (y1-y2)*(x3-x4) - (x1-x2)*(y3-y4); double tx = (y1*x2 - x1*y2)*(y4-y3) - (x1*x2 + y1*y2)*(x3+x4) + x3*(y2*y2 + x2*x2) + x4*(y1*y1 + x1*x1); double ty = (x1*x2 + y1*y2)*(-y4-y3) + (y1*x2 - x1*y2)*(x3-x4) + y3*(y2*y2 + x2*x2) + y4*(y1*y1 + x1*x1); return CGAffineTransformMake(a/D, -b/D, b/D, a/D, tx/D, ty/D); } I have tried to read up on the way matrix's work, but cannot figure it out entirely. More likely to be the issue is the calculations, which as I mention is not my strong point. What I need from this routine is a transform that performs my rotation but ignores scale - so the distance between the 2 finger touch points is ignored and scale is not affected. I have looked at other routines on the internet to handle multi-touch rotation but all the ones I tried had issues in some way or other, whereas the above code is spot on for scale and rotate actions. Any help appreciated!

  Read the article

• How can I provide maximum integration between a calendar-like webapp and desktop calendar applicatio

  - by Joshua Carmody

  I've been assigned to upgrade/rewrite a webapp that my company uses to schedule conference calls. One of the goals of the upgrade is to improve integration between the application and our user's Outlook calendars (and ideally other calendar programs as well). At present, when a user is viewing the details of a scheduled conference call on the webapp, they can click an "Add to Outlook calendar" link, which points them to a dynamically generated .ical file. On most of our users' systems, Outlook opens the file by default, bringing up the "create calendar appointment" window with the concall information pre-populated. This link creates a 1-time appointment only, and has to be clicked on for each occurrence of the call. So if a call happened every Monday in June, you would have to click 4 links to add all the appointments to your calendar. This is the full extent of our current level of integration. Ideally, we will be able to upgrade the system so that users can "subscribe" to a con call, which would mean not just the current call, but all calls in a reoccurring series would appear in the user's calendar with a single click. If one call in a series was cancelled, or rescheduled, that call's appointment would change in the users' calendar, without the user having to do anything, and without upsetting the rest of the series' appointments. Also, any changes to the call's info (say, the phone number was changed) would automatically be updated in the Outlook calendars of anyone who subscribed, without them having to come back to the webapp to double-check that their information is up to date. Ideally this would also work with other popular calendar programs, as well as Google Calendar. I don't know if we'll be able to achieve that level of integration, but I'd like to get as close to that as we can. Additional details and challenges: We aren't running Exchange on a public server, and I'm not likely to be able to get that changed Assume that our users are basically "the general internet public". Our users are not members of our office's network, nor can they be. We can't set up network logins or Exchange accounts for them. Some of our users are not using Outlook, but some other calendar program. Of the ones that are using Outlook, not all are using the same version. We have users in more than 50 countries that are using this webapp. Synchronization would be one-directional. Nobody can make changes in their own calendars and expect the server to reflect them/replicate them to other users Current conference calling application is written in ColdFusion. Rewrite will probably be in ASP.NET, but I haven't confirmed that yet. Solutions that work with either or both technologies are appreciated. I know that .ical files can theoretically contain more than one event, but in my own experiments I haven't had success in getting Outlook (2003) to add more than one event at a time using the .ical file method. Maybe someone knows how to set up a multi-event .ical file that Outlook will accept? Could a link to such an .ical file be "subscribed" to? Is there such thing as a calendar RSS feed? Could I simulate running an exchange server? Any other ideas? Thanks everyone!

  Read the article

• AES encryption/decryption java bouncy castle explanation?

  - by Programmer0

  Can someone please explain what this program is doing pointing out some of the major points? I'm looking at the code and I'm completely lost. I just need explanation on the encryption/decryption phases. I think it generates an AES 192 key at one point but I'm not 100% sure. I'm not sure what the byte/ivBytes are used for either. import java.security.Key; import javax.crypto.Cipher; import javax.crypto.KeyGenerator; import javax.crypto.spec.IvParameterSpec; public class RandomKey { public static void main(String[] args) throws Exception { byte[] input = new byte[] { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07 }; byte[] ivBytes = new byte[] { 0x00, 0x00, 0x00, 0x01, 0x04, 0x05, 0x06, 0x07, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 }; //initializing a new initialization vector IvParameterSpec ivSpec = new IvParameterSpec(ivBytes); //what does this actually do? Cipher cipher = Cipher.getInstance("AES/CTR/NoPadding", "BC"); //what does this do? KeyGenerator generator = KeyGenerator.getInstance("AES","BC"); //I assume this generates a key size of 192 bits generator.init(192); //does this generate a random key? Key encryptKey = generator.generateKey(); System.out.println("input: " +toHex(input)); //encryption phase cipher.init(Cipher.ENCRYPT_MODE, encryptKey, ivSpec); //what is this doing? byte[] cipherText = new byte[cipher.getOutputSize(input.length)]; //what is this doing? int ctLength = cipher.update(input, 0, input.length, cipherText,0); //getting the cipher text length i assume? ctLength += cipher.doFinal (cipherText, ctLength ); System.out.println ("Cipher: " +toHex(cipherText) + " bytes: " + ctLength); //decryption phase cipher.init(Cipher.DECRYPT_MODE, encryptKey, ivSpec); //storing the ciphertext in plaintext i'm assuming? byte[] plainText = new byte[cipher.getOutputSize(ctLength)]; int ptLength = cipher.update(cipherText, 0, ctLength, plainText, 0); //getting plaintextLength i think? ptLength= cipher.doFinal (plainText, ptLength); System.out.println("plain: " + toHex(plainText, ptLength)); } private static String digits = "0123456789abcdef"; public static String toHex(byte[] data, int length) { StringBuffer buf = new StringBuffer(); for (int i=0; i!= length; i++) { int v = data[i] & 0xff; buf.append(digits.charAt(v >>4)); buf.append(digits.charAt(v & 0xf)); } return buf.toString(); } public static String toHex(byte[] data) { return toHex(data, data.length); } }

  Read the article

• Database Table Schema and Aggregate Roots

  - by bretddog

  Hi, Applicaiton is single user, 1-tier(1 pc), database SqlCE. DataService layer will be (I think) : Repository returning domain objects and quering database with LinqToSql (dbml). There are obviously a lot more columns, this is simplified view. http://img573.imageshack.us/img573/3612/ss20110115171817w.png This is my first attempt of creating a 2 tables database. I think the table schema makes sense, but I need some reassurance or critics. Because the table relations looks quite scary to be honest. I'm hoping you could; Look at the table schema and respond if there are clear signs of troubles or errors that you spot right away.. And if you have time, Look at Program Summary/Questions, and see if the table layout makes makes sense to those points. Please be brutal, I will try to defend :) Program summary: a) A set of categories, each having a set of strategies (1:m) b) Each day a number of items will be produced. And each strategy MAY reference it. (So there can be 50 items, and a strategy may reference 23 of them) c) An item can be referenced by more than one strategy. So I think it's an m:m relation. d) Status values will be logged at fixed time-fractions through the day, for: - .... each Strategy.....each StrategyItem....each item e) An action on an item may be executed by a strategy that reference it. - This is logged as ItemAction (Could have called it StrategyItemAction) User Requsts b) - e) described the main activity mode of the program. To work with only today's DayLog , for each category. 2nd priority activity is retrieval of history, which typically will be From all categories, from day x to day y; Get all StrategyDailyLog. Questions First, does the overall layout look sound? I'm worried to see that there are so many relationships in all directions, connecting everything. Is this normal, or does it look like trouble? StrategyItem is made to represent an m:m relationship. Is it correct as I noted 1:m / 1:1 (marked red) ? StrategyItemTimeLog and ItemTimeLog; Logs values that both need to be retrieved together, when retreiving a StrategyItem. Reason I separated is that the first one is strategy-specific, and several strategies can reference same item. So I thought not to duplicate those values that are not dependent no strategy, but only on the item. Hence I also dragged out the LogTime, as it seems to be the only parameter to unite the logs. But this all looks quite disturbing with those 3 tables. Does it make sense at all? Or you have suggestion? Pink circles shows my vague attempt of Aggregate Root Paths. I've been thinking in terms of "what entity is responsible for delete". Though I'm unsure about the actual root. I think it's Category. Does it make sense related to User Requests described above?

  Read the article

• Rails ActiveRecord friendly code from a Complex Join, Sum, and Group query

  - by Chad M

  PROBLEM Hello, I am having no luck trying to break down this SQL statement into ActiveRecord/Rails friendly code and I'd like to learn how I can avoid a find_by_sql statement in this situation. Scenario I have users that create audits when they perform an action. Each audit is of a specific audit_activity. Each audit_activity is worth a certain number of points, based on score_weight. I need to find the total scores of each user, based on their total accumulated audit_activity score_weights. Eventually I'll need to rank them which means adding a sort to this as well. My Code Here is my sql and simplified versions of the tables in question. Any thoughts? SQL with full column names (for clarity) SELECT users.id, u.email, SUM(audit_activity.score_weight) FROM users JOIN audits ON users.id = audits.user_id JOIN audit_activities ON audit_activities.id = audits.audit_activity_id GROUP BY users.id; Models: User, Audit, AuditActivity User fields: id, email class User < ActiveRecord::Base include Clearance::User has_many :audits end Audit fields: id, user_id, audit_activity_id class Audit < ActiveRecord::Base belongs_to :user belongs_to :audit_activity end AuditActivity fields: id, score_weight class AuditActivity < ActiveRecord::Base has_many :audits end Example Data Here is a set of SQL statements so you can play with similar data I'm working with and see what comes up when the concerned query is run. You should just be able to copy/paste the whole thing into a database query browser. CREATE TABLE users( id INTEGER NOT NULL, email TEXT (25), PRIMARY KEY (id) ); CREATE TABLE audits( id INTEGER NOT NULL, user_id INTEGER, audit_activity_id INTEGER, PRIMARY KEY (id) ); CREATE TABLE audit_activities( id INTEGER NOT NULL, score_weight INTEGER, PRIMARY KEY (id) ); INSERT INTO users(id, email) VALUES(1, "[email protected]"); INSERT INTO users(id, email) VALUES(2, "[email protected]"); INSERT INTO users(id, email) VALUES(3, "[email protected]"); INSERT INTO audits(id, user_id, audit_activity_id) VALUES(1, 1, 1); INSERT INTO audits(id, user_id, audit_activity_id) VALUES(2, 1, 2); INSERT INTO audits(id, user_id, audit_activity_id) VALUES(3, 1, 1); INSERT INTO audits(id, user_id, audit_activity_id) VALUES(4, 1, 3); INSERT INTO audits(id, user_id, audit_activity_id) VALUES(5, 1, 1); INSERT INTO audits(id, user_id, audit_activity_id) VALUES(6, 1, 4); INSERT INTO audits(id, user_id, audit_activity_id) VALUES(7, 2, 4); INSERT INTO audits(id, user_id, audit_activity_id) VALUES(8, 2, 4); INSERT INTO audits(id, user_id, audit_activity_id) VALUES(9, 2, 4); INSERT INTO audits(id, user_id, audit_activity_id) VALUES(10, 3, 3); INSERT INTO audits(id, user_id, audit_activity_id) VALUES(11, 3, 2); INSERT INTO audits(id, user_id, audit_activity_id) VALUES(12, 3, 2); INSERT INTO audits(id, user_id, audit_activity_id) VALUES(13, 3, 2); INSERT INTO audits(id, user_id, audit_activity_id) VALUES(14, 3, 3); INSERT INTO audits(id, user_id, audit_activity_id) VALUES(15, 3, 1); INSERT INTO audits(id, user_id, audit_activity_id) VALUES(16, 3, 1); INSERT INTO audit_activities(id, score_weight) VALUES(1, 1); INSERT INTO audit_activities(id, score_weight) VALUES(2, 2); INSERT INTO audit_activities(id, score_weight) VALUES(3, 7); INSERT INTO audit_activities(id, score_weight) VALUES(4, 11); The Query Again, here is the query. SELECT u.id, u.email, SUM(aa.score_weight) FROM users u JOIN audits a ON u.id = a.user_id JOIN audit_activities aa ON aa.id = a.audit_activity_id GROUP BY u.id; Many Thanks, Chad

  Read the article

• Java: How to check the random letters from a-z, out of 10 letters minimum 2 letter should be a vowel

  - by kalandar

  I am writing a program to validate the following scenarios: Scenario 1: I am using the Random class from java.util. The random class will generate 10 letters from a-z and within 10 letter, minimum 2 letters must be a vowels. Scenario 2: When the player 1 and player 2 form a word from A-Z, he will score some points. There will be a score for each letter. I have already assigned the values for A-Z. At the end of the game, the system should display a scores for player 1 and player 2. How do i do it? Please help. I will post my code here. Thanks a lot. =========================================== import java.util.Random; import java.util.Scanner; public class FindYourWords { public static void main(String[] args) { Random rand = new Random(); Scanner userInput = new Scanner(System.in); //==================Player object=============================================== Player playerOne = new Player(); playerOne.wordScore = 0; playerOne.choice = "blah"; playerOne.turn = true; Player playerTwo = new Player(); playerTwo.wordScore = 0; playerTwo.choice = "blah"; playerTwo.turn = false; //================== Alphabet ================================================== String[] newChars = { "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z" }; //values of the 26 alphabets to be used int [] letterScore = {1,3,3,2,1,4,2,4,1,8,5,1,3,1,1,3,10,1,1,1,1,4,4,8,4,10}; // to assign score to the player1 and player 2 String[] vowel = { "a", "e", "i", "o", "u" }; // values for vowels int vow=0; System.out.println("FINDYOURWORDS\n"); int[] arrayRandom = new int[10]; //int array for word limiter String[] randomLetter = new String[10]; //storing the letters in newChars into this array //=============================================================================== boolean cont = true; while (cont) { if (playerOne.turn) { System.out.print("Letters of Player 1: "); } else if (!playerOne.turn) { System.out.print("Letters of Player 2: "); } for (int i = 0; i < arrayRandom.length; i++) { //running through the array limiter int r = rand.nextInt(newChars.length); //assigning random nums to the array of letters randomLetter[i] = newChars[r]; System.out.print(randomLetter[i]+ " "); } //input section for player System.out.println(""); System.out.println("Enter your word (or '@' to pass or '!' to quit): "); if (playerOne.turn) { playerOne.choice = userInput.next(); System.out.println(playerOne.turn); playerOne.turn = false; } else if (!playerOne.turn){ playerTwo.choice = userInput.next(); System.out.println(playerOne.turn); playerOne.turn = true; } //System.out.println(choice); String[] wordList = FileUtil.readDictFromFile("words.txt"); //Still dunno what this is for if (playerOne.choice.equals("@")) { playerOne.turn = false; } else if (playerTwo.choice.equals("@")) { playerOne.turn = true; } else if (playerOne.choice.equals("!")) { cont = false; } for (int i = 0; i < wordList.length; i++) { //System.out.println(wordList[i]); if (playerOne.choice.equalsIgnoreCase(wordList[i]) || playerTwo.choice.equalsIgnoreCase(wordList[i])){ } } } }}

  Read the article

• iPhone multi-touch move, scale and rotate, how to prevent scale?

  - by russhill

  I have existing code for tracking multi-touch positions and then moving, rotating and scaling the item - in this case an image - appropriately. The code works really well and in itself is perfect, however for this particular task, I need the movement and rotation ONLY. I have spent time trying to work out what is going on in this routine, but maths is not my strong point so wanted to see if anyone could assist? - (CGAffineTransform)incrementalTransformWithTouches:(NSSet *)touches { NSArray *sortedTouches = [[touches allObjects] sortedArrayUsingSelector:@selector(compareAddress:)]; NSInteger numTouches = [sortedTouches count]; // No touches if (numTouches == 0) { return CGAffineTransformIdentity; } // Single touch if (numTouches == 1) { UITouch *touch = [sortedTouches objectAtIndex:0]; CGPoint beginPoint = *(CGPoint *)CFDictionaryGetValue(touchBeginPoints, touch); CGPoint currentPoint = [touch locationInView:self.superview]; return CGAffineTransformMakeTranslation(currentPoint.x - beginPoint.x, currentPoint.y - beginPoint.y); } // If two or more touches, go with the first two (sorted by address) UITouch *touch1 = [sortedTouches objectAtIndex:0]; UITouch *touch2 = [sortedTouches objectAtIndex:1]; CGPoint beginPoint1 = *(CGPoint *)CFDictionaryGetValue(touchBeginPoints, touch1); CGPoint currentPoint1 = [touch1 locationInView:self.superview]; CGPoint beginPoint2 = *(CGPoint *)CFDictionaryGetValue(touchBeginPoints, touch2); CGPoint currentPoint2 = [touch2 locationInView:self.superview]; double layerX = self.center.x; double layerY = self.center.y; double x1 = beginPoint1.x - layerX; double y1 = beginPoint1.y - layerY; double x2 = beginPoint2.x - layerX; double y2 = beginPoint2.y - layerY; double x3 = currentPoint1.x - layerX; double y3 = currentPoint1.y - layerY; double x4 = currentPoint2.x - layerX; double y4 = currentPoint2.y - layerY; // Solve the system: // [a b t1, -b a t2, 0 0 1] * [x1, y1, 1] = [x3, y3, 1] // [a b t1, -b a t2, 0 0 1] * [x2, y2, 1] = [x4, y4, 1] double D = (y1-y2)*(y1-y2) + (x1-x2)*(x1-x2); if (D < 0.1) { return CGAffineTransformMakeTranslation(x3-x1, y3-y1); } double a = (y1-y2)*(y3-y4) + (x1-x2)*(x3-x4); double b = (y1-y2)*(x3-x4) - (x1-x2)*(y3-y4); double tx = (y1*x2 - x1*y2)*(y4-y3) - (x1*x2 + y1*y2)*(x3+x4) + x3*(y2*y2 + x2*x2) + x4*(y1*y1 + x1*x1); double ty = (x1*x2 + y1*y2)*(-y4-y3) + (y1*x2 - x1*y2)*(x3-x4) + y3*(y2*y2 + x2*x2) + y4*(y1*y1 + x1*x1); return CGAffineTransformMake(a/D, -b/D, b/D, a/D, tx/D, ty/D); } I have tried to read up on the way matrix's work, but cannot figure it out entirely. More likely to be the issue is the calculations, which as I mention is not my strong point. What I need from this routine is a transform that performs my movement and rotation but ignores scale - so the distance between the 2 finger touch points is ignored and scale is not affected. I have looked at other routines on the internet to handle multi-touch rotation but all the ones I tried had issues in some way or other (smoothness, jumping when lifting fingers etc), whereas the above code is spot on for move, scale and rotate actions. Any help appreciated!

  Read the article

• Lines don't overlap when they should Java Swing

  - by Sven

  I'm drawing lines in a JFrame on a self made gridPanel. Problem is, I draw the lines between 2 points. When I have a line that is between point 1 and point 2 and a line between point 2 and point 3, the lines should connect. This however isn,t the case, there is a small gap in between, no idea why. But it isn't drawing till the end of the specified point. (start point is correct.) Here is the code of the JFrame: public void initialize(){ this.setLayout(new BorderLayout()); this.setPreferredSize(new Dimension(500, 400)); gridPane = new GridPane(); gridPane.setBackground(Color.WHITE); gridPane.setSize(this.getPreferredSize()); gridPane.setLocation(0, 0); this.add(gridPane,BorderLayout.CENTER); //createSampleLabyrinth(); drawWall(0,5,40,5); //These are the 2 lines that don't connect. drawWall(40,5,80,5); this.pack(); } drawWall calls a method that calls a method in GridPane. The relevant code in gridPane: /** * Draws a wall on this pane. With the starting point being x1, y1 and its end x2,y2. * @param x1 * @param y1 * @param x2 * @param y2 */ public void drawWall(int x1, int y1, int x2, int y2) { Wall wall = new Wall(x1,y1,x2,y2, true); wall.drawGraphic(); wall.setLocation(x1, y1); wall.setSize(10000,10000); this.add(wall, JLayeredPane.DEFAULT_LAYER); this.repaint(); } This method creates a wall and puts it in the Jframe. The relevant code of the wall: public class Wall extends JPanel { private int x1; private int x2; private int y1; private int y2; private boolean black; /** * x1,y1 is the start point of the wall (line) end is x2,y2 * * @param x1 * @param y1 * @param x2 * @param y2 */ public Wall(int x1, int y1, int x2, int y2, boolean black) { this.x1 = x1; this.x2 = x2; this.y1 = y1; this.y2 = y2; this.black = black; setOpaque(false); } private static final long serialVersionUID = 1L; public void drawGraphic() { repaint(); } public void paintComponent(Graphics g) { super.paintComponent(g); Graphics2D g2 = (Graphics2D) g; if(black){ g2.setColor(Color.BLACK); g2.setStroke(new BasicStroke(8)); } else { g2.setColor(Color.YELLOW); g2.setStroke(new BasicStroke(3)); } g2.drawLine(x1, y1, x2, y2); } } So, where am I going wrong? The true/false is to determine if the wall should be black or yellow, nothing to be concerned about.

  Read the article

• texture colours opengl

  - by user1324894

  Hi I am making a simple 2D game in c++ and for the map I am doing texture mapping by using tiles and assigning textures to those tiles. However, when I run the programme the textures become black and white when I want them to be the colour they are in the .png image. This is my code: int worldMap[10][10] = { {0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0}, }; void background() { glClearColor(0.0,0.0,0.0,0.0); /**********************************************************************************************/ // Texture loading object nv::Image img; // Return true on success if(img.loadImageFromFile("Image_Loading/field.png")) { glGenTextures(1, &myTexture); glBindTexture(GL_TEXTURE_2D, myTexture); glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, GL_TRUE); glTexImage2D(GL_TEXTURE_2D, 0, img.getInternalFormat(), img.getWidth(), img.getHeight(), 0, img.getFormat(), img.getType(), img.getLevel(0)); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT ); glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT ); glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT, 16.0f); } else MessageBox(NULL, "Failed to load texture", "End of the world", MB_OK | MB_ICONINFORMATION); /**********************************************************************************************/ } void drawTiles (void) { //our function to draw the tiles for (int i = 0; i < 10; i++) //loop through the height of the map { for (int j = 0; j < 10; j++) //loop through the width of the map { if (worldMap[i][j] == 0) //if the map at this position contains a 0 { glBindTexture( GL_TEXTURE_2D, myTexture ); //bind our grass texture to our shape } glPushMatrix(); //push the matrix so that our translations only affect this tile glTranslatef(j, -i, 0); //translate the tile to where it should belong glBegin (GL_QUADS); //begin drawing our quads glTexCoord2d(10, 0); glVertex2f((-10 + mapX),(-10 + mapY)); //with our vertices we have to assign a texcoord glTexCoord2d(10, 0); glVertex2f((10 + mapX),(-10 + mapY)); //so that our texture has some points to draw to glTexCoord2d(10, 10); glVertex2f((10 + mapX),(10 + mapY)); glTexCoord2d(0, 10); glVertex2f((-10 + mapX),(10 + mapY)); glEnd(); glPopMatrix(); //pop the matrix } //end first loop } //end second loop } void display() { glClearColor (0.0,0.0,0.0,1.0); glClear(GL_COLOR_BUFFER_BIT); /**********************************************************************************************/ glMatrixMode( GL_PROJECTION ); glLoadIdentity(); gluOrtho2D( -5, 5, -5, 5); glMatrixMode( GL_MODELVIEW ); glEnable(GL_TEXTURE_2D); glBindTexture(GL_TEXTURE_2D, myTexture); glEnable(GL_BLEND); glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); drawTiles(); glDisable(GL_TEXTURE_2D); glDisable(GL_BLEND); /**********************************************************************************************/ } void character () { glBegin(GL_POLYGON); glVertex2f((-0.5+characterX),(-0.5 +characterY)); glVertex2f((-0.5+characterX),(0.5+characterY)); glVertex2f((0.5+characterX),(0.5+characterY)); glVertex2f((0.5+characterX),(-0.5+characterY)); glTranslatef(characterX, characterY, 0.0f); glEnd(); } Can anybody help please?

  Read the article

• How to manipulate data after its retrieved via remote database

  - by bMon

  So I've used code examples from all over the net and got my app to accurately call a .php file on my server, retrieve the JSON data, then parse the data, and print it. The problem is that its just printing to the screen for sake of the tutorial I was following, but now I need to use that data in other places and need help figuring out that process. The ultimate goal is to return my db query with map coordinates, then plot them on a google map. I have another app in which I manually plot points on a map, so I'll be integrating this app with that once I can get my head around how to correctly manipulate the data returned. public class Remote extends Activity { /** Called when the activity is first created. */ TextView txt; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); // Create a crude view - this should really be set via the layout resources // but since its an example saves declaring them in the XML. LinearLayout rootLayout = new LinearLayout(getApplicationContext()); txt = new TextView(getApplicationContext()); rootLayout.addView(txt); setContentView(rootLayout); // Set the text and call the connect function. txt.setText("Connecting..."); //call the method to run the data retreival txt.setText(getServerData(KEY_121)); } public static final String KEY_121 = "http://example.com/mydbcall.php"; private String getServerData(String returnString) { InputStream is = null; String result = ""; //the year data to send //ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(); //nameValuePairs.add(new BasicNameValuePair("year","1970")); try{ HttpClient httpclient = new DefaultHttpClient(); HttpPost httppost = new HttpPost(KEY_121); HttpResponse response = httpclient.execute(httppost); HttpEntity entity = response.getEntity(); is = entity.getContent(); }catch(Exception e){ Log.e("log_tag", "Error in http connection "+e.toString()); } //convert response to string try{ BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8); StringBuilder sb = new StringBuilder(); String line = null; while ((line = reader.readLine()) != null) { sb.append(line + "\n"); } is.close(); result=sb.toString(); }catch(Exception e){ Log.e("log_tag", "Error converting result "+e.toString()); } //parse json data try{ JSONArray jArray = new JSONArray(result); for(int i=0;i<jArray.length();i++){ JSONObject json_data = jArray.getJSONObject(i); Log.i("log_tag","longitude: "+json_data.getDouble("longitude")+ ", latitude: "+json_data.getDouble("latitude") ); //Get an output to the screen returnString += "\n\t" + jArray.getJSONObject(i); } }catch(JSONException e){ Log.e("log_tag", "Error parsing data "+e.toString()); } return returnString; } } So the code: returnString += "\n\t" + jArray.getJSONObject(i); is what is currently printing to the screen. What I have to figure out is how to get the data into something I can reference in other spots in the program, and access the individual elements ie: double longitude = jArray.getJSONObject(3).longitude; or something to that effect.. I figure the class getServerData will have to return a Array type or something? Any help is appreciated, thanks.

  Read the article

• Problem using delete[] (Heap corruption) when implementing operator+= (C++)

  - by Darel

  I've been trying to figure this out for hours now, and I'm at my wit's end. I would surely appreciate it if someone could tell me when I'm doing wrong. I have written a simple class to emulate basic functionality of strings. The class's members include a character pointer data (which points to a dynamically created char array) and an integer strSize (which holds the length of the string, sans terminator.) Since I'm using new and delete, I've implemented the copy constructor and destructor. My problem occurs when I try to implement the operator+=. The LHS object builds the new string correctly - I can even print it using cout - but the problem comes when I try to deallocate the data pointer in the destructor: I get a "Heap Corruption Detected after normal block" at the memory address pointed to by the data array the destructor is trying to deallocate. Here's my complete class and test program: #include <iostream> using namespace std; // Class to emulate string class Str { public: // Default constructor Str(): data(0), strSize(0) { } // Constructor from string literal Str(const char* cp) { data = new char[strlen(cp) + 1]; char *p = data; const char* q = cp; while (*q) *p++ = *q++; *p = '\0'; strSize = strlen(cp); } Str& operator+=(const Str& rhs) { // create new dynamic memory to hold concatenated string char* str = new char[strSize + rhs.strSize + 1]; char* p = str; // new data char* i = data; // old data const char* q = rhs.data; // data to append // append old string to new string in new dynamic memory while (*p++ = *i++) ; p--; while (*p++ = *q++) ; *p = '\0'; // assign new values to data and strSize delete[] data; data = str; strSize += rhs.strSize; return *this; } // Copy constructor Str(const Str& s) { data = new char[s.strSize + 1]; char *p = data; char *q = s.data; while (*q) *p++ = *q++; *p = '\0'; strSize = s.strSize; } // destructor ~Str() { delete[] data; } const char& operator[](int i) const { return data[i]; } int size() const { return strSize; } private: char *data; int strSize; }; ostream& operator<<(ostream& os, const Str& s) { for (int i = 0; i != s.size(); ++i) os << s[i]; return os; } // Test constructor, copy constructor, and += operator int main() { Str s = "hello"; // destructor for s works ok Str x = s; // destructor for x works ok s += "world!"; // destructor for s gives error cout << s << endl; cout << x << endl; return 0; }

  Read the article

• How do I process the largest match first in PHP?

  - by animuson

  Ok, so I tried searching around first but I didn't exactly know how to word this question or a search phrase. Let me explain. I have data that looks like this: <!-- data:start --> <!-- 0:start --> <!-- 0:start -->0,9<!-- 0:stop --> <!-- 1:start -->0,0<!-- 1:stop --> <!-- 2:start -->9,0<!-- 2:stop --> <!-- 3:start -->9,9<!-- 3:stop --> <!-- 4:start -->0,9<!-- 4:stop --> <!-- 0:stop --> <!-- 1:start --> <!-- 0:start -->1,5<!-- 0:stop --> <!-- 1:start -->1,6<!-- 1:stop --> <!-- 2:start -->3,6<!-- 2:stop --> <!-- 3:start -->3,8<!-- 3:stop --> <!-- 4:start -->4,8<!-- 4:stop --> <!-- 1:stop --> <!-- 2:start --> <!-- 0:start -->0,7<!-- 0:stop --> <!-- 1:start -->1,7<!-- 1:stop --> <!-- 2:stop --> <!-- data:stop --> So it's basically a bunch of points. Here is the code I'm currently using to try and parse it so that it would create an array like so: Array ( 0 => Array ( 0 => "0,9", 1 => "0,0", 2 => "9,0", 3 => "9,9", 4 => "0,9" ), 1 => Array ( 0 => "1,5", 1 => "1,6", 2 => "3,6", 3 => "3,8", 4 => "4,8" ), 2 => Array ( 0 => "0,7", 1 => "1,7" ) ) However, it is returning an array that looks like this: Array ( 0 => "0,9", 1 => "0,0", 2 => "9,0" ) Viewing the larger array that I have on my screen, you see that it's setting the first instance of that variable when matching. So how do I get it to find the widest match first and then process the insides. Here is the function I am currently using: function explosion($text) { $number = preg_match_all("/(<!-- ([\w]+):start -->)\n?(.*?)\n?(<!-- \\2:stop -->)/s", $text, $matches, PREG_SET_ORDER); if ($number == 0) return $text; else unset($item); foreach ($matches as $item) if (empty($data[$item[2]])) $data[$item[2]] = $this->explosion($item[3]); return $data; } I'm sure it will be something stupid and simple that I've overlooked, but that just makes it an easy answer for you I suppose.

  Read the article

• iOS: Interpreted code - where do they draw the line?

  - by d7samurai

  Apple's iOS developer guidelines state: 3.3.2 — An Application may not itself install or launch other executable code by any means, including without limitation through the use of a plug-in architecture, calling other frameworks, other APIs or otherwise. No interpreted code may be downloaded or used in an Application except for code that is interpreted and run by Apple’s Documented APIs and built-in interpreter(s). Assuming that downloading data - like XML and images (or a game level description), for example - at run-time is allowed (as is my impression), I am wondering where they draw the line between "data" and "code". Picture the scenario of an app that delivers interactive "presentations" to users (like a survey, for instance). Presentations are added continuously to the server and different presentations are made available to different users, so they cannot be part of the initial app download (this is the whole point). They are described in XML format, but being interactive, they might contain conditional branching of this sort (shown in pseudo form to exemplify): <options id="Gender"> <option value="1">Male</option> <option value="2">Female</option> </options> <branches id="Gender"> <branch value="1"> <image src="Man" /> </branch> <branch value="2"> <image src="Woman" /> </branch> </branches> When the presentation is "played" within the app, the above would be presented in two steps. First a selection screen where the user can click on either of the two choices presented ("Male" or "Female"). Next, an image will be [downloaded dynamically] and displayed based on the choice made in the previous step. Now, it's easy to imagine additional tags describing further logic still. For example, a containing tag could be added: <loop count="3"> <options... /> <branches... /> </loop> The result here being that the selection screen / image screen pair would be sequentially presented three times over, of course. Or imagine some description of a level in a game. It's easy to view that as passive "data", but if it includes, say, several doorways that the user can go through and with various triggers, traps and points attached to them etc - isn't that the same as using a script - or, indeed, interpreted code - to describe options and their conditional responses? Assuming that the interpretation engine for this XML data is already present in the app and that such presentations can only be consumed (not created or edited) in the app, how would this fare against Apple's iOS guidelines? Doesn't XML basically constitute a scripting language (couldn't any interpreted programming language simply be described by XML) in this sense? Would it be OK if the proprietary scripting language (ref the XML used above) was strictly sandboxed (how can they tell?) and not given access to the operating system in any way (but able to download content dynamically - and upload results to the authoring server)? Where does the line go?

  Read the article

• How to debug KVO

  - by user8472

  In my program I use KVO manually to observe changes to values of object properties. I receive an EXC_BAD_ACCESS signal at the following line of code inside a custom setter: [self willChangeValueForKey:@"mykey"]; The weird thing is that this happens when a factory method calls the custom setter and there should not be any observers around. I do not know how to debug this situation. Update: The way to list all registered observers is observationInfo. It turned out that there was indeed an object listed that points to an invalid address. However, I have no idea at all how it got there. Update 2: Apparently, the same object and method callback can be registered several times for a given object - resulting in identical entries in the observed object's observationInfo. When removing the registration only one of these entries is removed. This behavior is a little counter-intuitive (and it certainly is a bug in my program to add multiple entries at all), but this does not explain how spurious observers can mysteriously show up in freshly allocated objects (unless there is some caching/reuse going on that I am unaware of). Modified question: How can I figure out WHERE and WHEN an object got registered as an observer? Update 3: Specific sample code. ContentObj is a class that has a dictionary as a property named mykey. It overrides: + (BOOL)automaticallyNotifiesObserversForKey:(NSString *)theKey { BOOL automatic = NO; if ([theKey isEqualToString:@"mykey"]) { automatic = NO; } else { automatic=[super automaticallyNotifiesObserversForKey:theKey]; } return automatic; } A couple of properties have getters and setters as follows: - (CGFloat)value { return [[[self mykey] objectForKey:@"value"] floatValue]; } - (void)setValue:(CGFloat)aValue { [self willChangeValueForKey:@"mykey"]; [[self mykey] setObject:[NSNumber numberWithFloat:aValue] forKey:@"value"]; [self didChangeValueForKey:@"mykey"]; } The container class has a property contents of class NSMutableArray which holds instances of class ContentObj. It has a couple of methods that manually handle registrations: + (BOOL)automaticallyNotifiesObserversForKey:(NSString *)theKey { BOOL automatic = NO; if ([theKey isEqualToString:@"contents"]) { automatic = NO; } else { automatic=[super automaticallyNotifiesObserversForKey:theKey]; } return automatic; } - (void)observeContent:(ContentObj *)cObj { [cObj addObserver:self forKeyPath:@"mykey" options:0 context:NULL]; } - (void)removeObserveContent:(ContentObj *)cObj { [cObj removeObserver:self forKeyPath:@"mykey"]; } - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context { if (([keyPath isEqualToString:@"mykey"]) && ([object isKindOfClass:[ContentObj class]])) { [self willChangeValueForKey:@"contents"]; [self didChangeValueForKey:@"contents"]; } } There are several methods in the container class that modify contents. They look as follows: - (void)addContent:(ContentObj *)cObj { [self willChangeValueForKey:@"contents"]; [self observeDatum:cObj]; [[self contents] addObject:cObj]; [self didChangeValueForKey:@"contents"]; } And a couple of others that provide similar functionality to the array. They all work by adding/removing themselves as observers. Obviously, anything that results in multiple registrations is a bug and could sit somewhere hidden in these methods. My question targets strategies on how to debug this kind of situation. Alternatively, please feel free to provide an alternative strategy for implementing this kind of notification/observer pattern.

  Read the article

• Associating an Object with other Objects and Properties of those Objects

  - by alzoid

  I am looking for some help with designing some functionality in my application. I already have something similar designed but this problem is a little different. Background: In my application we have different Modules. Data in each module can be associated to other modules. Each Module is represented by an Object in our application. Module 1 can be associated with Module 2 and Module 3. Currently I use a factory to provide the proper DAO for getting and saving this data. It looks something like this: class Module1Factory { public static Module1BridgeDAO createModule1BridgeDAO(int moduleid) { switch (moduleId) { case Module.Module2Id: return new Module1_Module2DAO(); case Module.Module3Id: return new Module1_Module3DAO(); default: return null; } } } Module1_Module2 and Module1_Module3 implement the same BridgeModule interface. In the database I have a Table for every module (Module1, Module2, Module3). I also have a bridge table for each module (they are many to many) Module1_Module2, Module1_Module3 etc. The DAO basically handles all code needed to manage the association and retrieve its own instance data for the calling module. Now when we add new modules that associate with Module1 we simply implement the ModuleBridge interface and provide the common functionality. New Development We are adding a new module that will have the ability to be associated with other Modules as well as specific properties of that module. The module is basically providing the user the ability to add their custom forms to our other modules. That way they can collect additional information along with what we provide. I want to start associating my Form module with other modules and their properties. Ie if Module1 has a property Category, I want to associate an instance From data with that property. There are many Forms. If a users creates an instance of Module2, they may always want to also have certain form(s) attached to that Module2 instance. If they create an instance of Module2 and select Category 1, then I may want additional Form(s) created. I prototyped something like this: Form FormLayout (contains the labels and gui controls) FormModule (associates a form with all instances of a module) Form Instance (create an instance of a form to be filled out) As I thought about it I was thinking about making a new FormModule table/class/dao for each Module and Property that I add. So I might have: FormModule1 FormModule1Property1 FormModule1Property2 FormModule1Property3 FormModule1Property4 FormModule2 FormModule3 FormModule3Property1 Then as I did previously, I would use a factory to get the proper DAO for dealing with all of these. I would hand it an array of ids representing different modules and properties and it would return all of the DAOs that I need to call getForms(). Which in turn would return all of the forms for that particular bridge. Some points This will be for a new module so I dont need to expand on the factory code I provided. I just wanted to show an example of what I have done in the past. The new module can be associated with: Other Modules (ie globally for any instance of that module data), Other module properties (ie only if the Module instance has a certian value in one of its properties) I want to make it easy for developers to add associations with other modules and properties easily Can any one suggest any design patterns or strategy's for achieving this? If anything is unclear please let me know. Thank you, Al

  Read the article

• XML Outputting - PHP vs JS vs Anything Else?

  - by itsphil

  Hi everyone, I am working on developing a Travel website which uses XML API's to get the data. However i am relatively new to XML and outputting it. I have been experimenting with using PHP to output a test XML file, but currently the furthest iv got is to only output a few records. As it the questions states i need to know which technology will be best for this project. Below iv included some points to take into consideration. The website is going to be a large sized, heavy traffic site (expedia/lastminute size) My skillset is PHP (intermediate/high skilled) & Javascript (intermediate/high skilled) Below is an example of the XML that the API is outputting: <?xml version="1.0"?> <response method="###" success="Y"> <errors> </errors> <request> <auth password="test" username="test" /> <method action="###" sitename="###" /> </request> <results> <line id="6" logourl="###" name="Line 1" smalllogourl="###"> <ships> <ship id="16" name="Ship 1" /> <ship id="453" name="Ship 2" /> <ship id="468" name="Ship 3" /> <ship id="356" name="Ship 4" /> </ships> </line> <line id="63" logourl="###" name="Line 2" smalllogourl="###"> <ships> <ship id="492" name="Ship 1" /> <ship id="454" name="Ship 2" /> <ship id="455" name="Ship 3" /> <ship id="421" name="Ship 4" /> <ship id="401" name="Ship 5" /> <ship id="404" name="Ship 6" /> <ship id="405" name="Ship 7" /> <ship id="406" name="Ship 8" /> <ship id="407" name="Ship 9" /> <ship id="408" name="Ship 10" /> </ships> </line> <line id="41" logourl="###"> <ships> <ship id="229" name="Ship 1" /> <ship id="230" name="Ship 2" /> <ship id="231" name="Ship 3" /> <ship id="445" name="Ship 4" /> <ship id="570" name="Ship 5" /> <ship id="571" name="Ship 6" /> </ships> </line> </results> </response> If possible when suggesting which technlogy is best for this project, if you could provide some getting started guides or any information would be very much appreciated. Thank you for taking the time to read this.

  Read the article

• NEED your opinion on .net Profile class VS session vars

  - by Ted

  To save trips to sql db in my older apps, I store *dozens of data points about the current user in an array and then store the array in a session. For example, info that might be used repeatedly during user’s session might be stored… Dim a(7) as string a(0) = “FirstName” a(1) = “LastName” a(2) = “Address” a(3) = “Address2” a(4) = “City” a(5) = “State” a(6) = “Zip” session.add(“s_a”, a) *Some apps have an array 100 in size. That is something I learned in my asp classic days. Referencing the correct index can be laborsome and I find it difficult to go back and add another data point in the array grouped with like data. For example, suppose I need to add Middle Initial to the array as a design alteration. Unless I redo the whole index mapping, I have to stick Middle Initial in the next open slot, which might be in the 50s. NOW, I am considering doing something easier to reference each time (eliminating the need to know the index of the value wanted). So I am looking to do this… session.add(“Firstname”, “FirstName”) session.add(“Lastname”, “LastName”) session.add(“Address”, “Address”) etc. BUT, before I do this, I would like some guidance. I am afraid this might be less efficient, even though easier to use. I don’t know if a new session object is created for each data point or if there is only one session object, and I am adding a name/value pair to that object? If I am adding a name/value pair to a single object, that seems like a good idea. Does anyone know? Or is there a more preferred way? Built-in Profile class? Re: Profile class I have an internal debate about scope. It seems that the .net Profile class is good for storing app-SPECIFIC user settings (i.e. style theme, object display properties, user role, etc.) The examples I give are information whose values are selected/edited by the user to customize the application experience. This information is not typically stored/edited elsewhere in the app db. But when you have data that 1) is stored already in the app db and 2) can be altered by other users (in this case: company reps may update client's status, address, etc.), then the persistence of the Profile data may be an issue. In this case, the Profile would need to be reset at the beginning and dropped like a session.abandon at the end of each user's session to prevent reloading info that had since been edited by someone. I believe this is possible, but not sure Currently, I use the session array to store both scopes, app-specific and user-specific data. If my session plan is good, I think I will create a class to set/get values from the session also. I appreciate your thoughts. I would like to know how others have handled this type of situation. Thanks.

  Read the article

• How to call virtual function of an object in C++

  - by SoonDead

  I'm struggling with calling a virtual function in C++. I'm not experienced in C++, I mainly use C# and Java so I might have some delusions, but bear with me. I have to write a program where I have to avoid dynamic memory allocation if possible. I have made a class called List: template <class T> class List { public: T items[maxListLength]; int length; List() { length = 0; } T get(int i) const { if (i >= 0 && i < length) { return items[i]; } else { throw "Out of range!"; } }; // set the value of an already existing element void set(int i, T p) { if (i >= 0 && i < length) { items[i] = p; } else { throw "Out of range!"; } } // returns the index of the element int add(T p) { if (length >= maxListLength) { throw "Too many points!"; } items[length] = p; return length++; } // removes and returns the last element; T pop() { if (length > 0) { return items[--length]; } else { throw "There is no element to remove!"; } } }; It just makes an array of the given type, and manages the length of it. There is no need for dynamic memory allocation, I can just write: List<Object> objects; MyObject obj; objects.add(obj); MyObject inherits form Object. Object has a virtual function which is supposed to be overridden in MyObject: struct Object { virtual float method(const Input& input) { return 0.0f; } }; struct MyObject: public Object { virtual float method(const Input& input) { return 1.0f; } }; I get the elements as: objects.get(0).method(asdf); The problem is that even though the first element is a MyObject, the Object's method function is called. I'm guessing there is something wrong with storing the object in an array of Objects without dynamically allocating memory for the MyObject, but I'm not sure. Is there a way to call MyObject's method function? How? It's supposed to be a heterogeneous collection btw, so that's why the inheritance is there in the first place. If there is no way to call the MyObject's method function, then how should I make my list in the first place?

  Read the article

• Javascript/Jquery Super Scrollorama Navigation Issues

  - by Rosencruez

  On a Wordpress site I am currently working on, my client wanted the different sections of the front page to slide up from the bottom and cover up the previous section, like a wipe or slide transition. Using super scrollorama found here: http://johnpolacek.github.com/superscrollorama/, I managed to achieve the desired result. Next, I needed to create a navigation menu on the front page only. I did so, and set anchors at various different points on the pages. I also used the scrollTo library for scolling animations when I click the nav menu links. However, there are a number of problems I have encountered: When at the top and I click "showcase", it brings me down to the showcase section, but the products section (the div right after it) is overlapping it. Other divs seems to have the same problem of the following divs overlapping the current one I can only navigate forwards. When I try to go backwards, it won't (except for "Home") I thought it might have something to do with the CSS "top" property of the divs, so I tried resetting them every time the click function kicked in, but it didn't work. So I removed it for the time being. Currently set the javascript to prevent the default action of scrolling to the anchors and instead setting it to scroll to the actual divs themselves. However, I'm still having the same issues. Here is the site I am currently working on: http://breathe.simalam.ca/ Here is the javascript for the scrolling: $(document).ready(function() { jQuery('.home-link').click(function(e){ e.preventDefault(); jQuery(window).scrollTo(0, 1000, {queue:true}); }); jQuery('.showcase-link').click(function(e){ e.preventDefault(); jQuery(window).scrollTo('#showcase_content', 1000, {queue:true}); }); jQuery('.products-link').click(function(e){ e.preventDefault(); jQuery(window).scrollTo('#products_content', 1000, {queue:true}); }); jQuery('.about-link').click(function(e){ e.preventDefault(); jQuery(window).scrollTo('#about_content', 1000, {queue:true}); }); jQuery('.locator-link').click(function(e){ e.preventDefault(); jQuery(window).scrollTo('#locator_content', 1000, {queue:true}); }); jQuery('.contact-link').click(function(e){ e.preventDefault(); jQuery(window).scrollTo('#contact_content', 1000, {queue:true}); }); }); scrollorama code: $(document).ready(function() { $('#wrapper').css('display','block'); var controller = $.superscrollorama(); var pinDur = 4000; /* set duration of pin scroll in pixels */ // create animation timeline for pinned element var pinAnimations = new TimelineLite(); pinAnimations .append([ TweenMax.to($('#showcase'), .5, {css:{top:0}}) ], .5) .append([ TweenMax.to($('#products'), .5, {css:{top:0}}) ], .5) .append([ TweenMax.to($('#about'), .5, {css:{top:0}}) ], .5) .append([ TweenMax.to($('#locator'), .5, {css:{top:0}}) ], .5) .append([ TweenMax.to($('#contact'), .5, {css:{top:0}}) ], .5) .append(TweenMax.to($('#pin-frame-unpin'), .5, {css:{top:'100px'}})); controller.pin($('#examples-pin'), pinDur, { anim:pinAnimations, onPin: function() { $('#examples-pin').css('height','100%'); }, onUnpin: function() { $('#examples-pin').css('height','2000px'); } }); }); All of the section divs are inside a parent div. The section divs all have a height, width, and top of 100%. The parent div containing all of these section divs are as follows: #examples-pin { position: relative; /* relative positioning for transitions to work? */ width: 101%; /* max width */ height: 2000px; /* height of 2000px for now */ overflow: hidden; /* hide the overflow for transitions to work */ margin-bottom: -200px; /* negative bottom margin */ }

  Read the article

< Previous Page | 233 234 235 236 237 238 239 240 241 242 243 244  | Next Page >