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• How to get the Entire Function from a file

  - by SoLoGHoST

  Ok, I'm reading through a file now, line by line. I know each functions name in the file, since it is defined elsewhere in an XML document. That is what should be this: function function_name Where function_name is the name of the function. I get all of the function definitions from an XML document that I already have put into an array of function names, and I need to grab just those functions from the php file. And rebuild that php file so that it only has those functions in it. That is to say, if a php file has more functions than what is defined in the XML tag, than I need to strip out those functions, and rewrite the .php file with only the functions that the user specified in the XML file. So, the dilemma I face is how to determine the END of a function reading line by line, and I'm aware that functions can have function within them. So I don't want to remove the functions within them. Just functions that are standalone and aren't defined within the accompanying XML file. Any ideas on how to do this?? Thanks :)

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• Codeigniter Session Data not available in other pages after login

  - by jswat

  So, I have set up a login page that verifies the user's credentials, and then sets codeigniter session data 'email' and 'is_logged_in' and a few other items. The first page after the login, the data is accessible. After that page, I can no longer access the session data. In fact, if I try reloading that first page, the session data is gone. I have tried storing it in the database, storing it unencrypted (bad idea I know, but it was for troubleshooting), and storing it encrypted. I have autoloaded the session library in config.php. Here's an example of the code I'm using to set the session data: $data = array( 'email' => $this->input->post('username'), 'is_logged_in' => true ); $this->session->set_userdata($data); And to retrieve it, I'm using : $this->session->userdata('email'); Or $this->session->userdata('is_logged_in'); I've done lots of work with PHP and cookies, and sessions before, but this is my first project with Codeigniter and I'm perplexed. Could it have something to do with directory issues? I have the login page and process controlled by a 'login' controller, and then it redirects to a 'site' controller. Thanks for your help, and please let me know if I need to clarify anything.

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• Open txt files from a directory, compare the values, and output the top 15 in PHP

  - by Anon

  Hello, I recently designed a referral game website for the fun of it. There's a simple MySQL user system with a email verification. It's using the UserCake user management system. On top of this i added a php page that the user could give to "victims" that when they visit it they get "infected" and can infect other users or "victims". This page uses GET to get the username from the url. I have a folder that when a user registers it creates a file with 4 digits and then the username. (ex; 0000Username.txt) All the numbers are the same, it's just so that if a user discovers the folder they won't be able to find the files. There is also a txt file in the same format with IPS in the name. (ex; 0000IPSUsername.txt) The file when visited gets the username from the url, then checks if the text file for that username exists. If the username is present in the url, and a valid user it opens the IPS file and adds the IP of the visitor, then opens the user text file, takes the value and adds one to it, and saves. At the end it makes the difference between saying "You are infected, Username has infected (amount) people." or just you have been infected. Now to what i need! I need to add a hi-scores to the website so people can compete to be the one with the most "infections". I thought i could use readdir to get a list of the files and open them with the value in an array, but i need it to also strip the username from the file name. It would be best if it just saves to a text file like "Username | value" because then i can add echo's of the html tags and have it include the file in the page i want it to be one. Many thanks in advance.

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• php class scope when calling a non-method function not accessing all class members

  - by Aglystas

  So I'm using a stand alone function from within a class that that uses the class it's being called from. Here's the function function catalogProductLink($product_id,$product_name,$categories=true) { //This is the class that the function is called from global $STATE; if ($categories) { //The $STATE->category_id is the property I want to access, which I can't if (is_array($STATE->category_id)) { foreach($STATE->category_id as $cat_id) { if ($cat_id == 0) continue; $str .= "c$cat_id/"; } } } $str .= catalogUrlKeywords($product_name).'-p'.$product_id.'.html'; return $str; } And here's the function call, which is being made from within the $STATE class. $redirect = catalogProductLink($this->product_id, $tempProd->product_name, true, false); The object that I need access to is the $STATE object that has been declared global. Prior to this function call there are lots of public properties populated, but when I look at the $STATE object within the function scope it loses all the properties but one, product_id. The property that matters for this function is the category_id property, which is an array of category id's. I'm wondering why I don't have access to all the public properties of the $STATE object and how I can get access to them.

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• C socket programming: client send() but server select() doesn't see it

  - by Fantastic Fourier

  Hey all, I have a server and a client running on two different machines where the client send()s but the server doesn't seem to receive the message. The server employs select() to monitor sockets for any incoming connections/messages. I can see that when the server accepts a new connection, it updates the fd_set array but always returns 0 despite the client send() messages. The connection is TCP and the machines are separated by like one router so dropping packets are highly unlikely. I have a feeling that it's not select() but perhaps send()/sendto() from client that may be the problem but I'm not sure how to go about localizing the problem area. while(1) { readset = info->read_set; ready = select(info->max_fd+1, &readset, NULL, NULL, &timeout); } above is the server side code where the server has a thread that runs select() indefinitely. rv = connect(sockfd, (struct sockaddr *) &server_address, sizeof(server_address)); printf("rv = %i\n", rv); if (rv < 0) { printf("MAIN: ERROR connect() %i: %s\n", errno, strerror(errno)); exit(1); } else printf("connected\n"); sleep(3); char * somemsg = "is this working yet?\0"; rv = send(sockfd, somemsg, sizeof(somemsg), NULL); if (rv < 0) printf("MAIN: ERROR send() %i: %s\n", errno, strerror(errno)); printf("MAIN: rv is %i\n", rv); rv = sendto(sockfd, somemsg, sizeof(somemsg), NULL, &server_address, sizeof(server_address)); if (rv < 0) printf("MAIN: ERROR sendto() %i: %s\n", errno, strerror(errno)); printf("MAIN: rv is %i\n", rv); and this is the client side where it connects and sends messages and returns connected MAIN: rv is 4 MAIN: rv is 4 any comments or insightful insights are appreciated.

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• Accessing Element Count and Values Within a Hidden Div

  - by Tegan Snyder

  I'm having trouble grabbing the TR count in JQuery of a table that inside a DIV set to be hidden. Here is an example: <div id="questions" style="display: none;"> <table id="tbl_questions"> <thead> <tr> <th>Question</th> <th>Weight</th> </tr> </thead> <tbody> <tr id="q0"> <td id="td_question0">Some Question 0</td> <td id="td_wieght0">Some Weight 0</td> </tr> <tr id="q1"> <td id="td_question1">Some Question 1</td> <td id="td_wieght1">Some Weight 1</td> </tr> </tbody> </table> </div> Note the table is within the containing div. It's set to display: none. When I try to run this JQuery code it returns 0. var question_count = $("#tbl_questions> tr").size(); alert(question_count); Any ideas? I'm try to locate the count so I can then build an array of each question and weight in the table. Since the ID's provide me with an index this should be simple, but is the fact that it is contained in a hidden DIV going to be a problem just as the above question? Thanks, Tegan Snyder

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• Linked List push()

  - by JKid314159

  The stack is initialized with a int MaxSize =3. Then I push one int onto the list. " Pushed:" is returned to the console. Program crashes here. I think my logic is flawed but unsure. Maybe an infinite loop or unmet condition? Thanks for your help. I'm trying to traverse the list to the last node in the second part of the full() method. I implemented this stack as array based so must implement this method full() as this method is inside of main class. while(!stacker.full()) { cout << "Enter number = "; cin >> intIn; stacker.push(intIn); cout << "Pushed: " << intIn << endl; }//while Call to LinkListStack.cpp to class LinkList full(). int LinkList::full() { if(head == NULL) { top = 0; } else { LinkNode * tmp1; LinkNode * tmp2; tmp1 = head; while(top != MaxSize) { if(tmp1->next != NULL){ tmp2 = tmp1->next; tmp1 = tmp2; ++top; }//if }//while }//else return (top + 1 == MaxSize); }

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• Gdata JavaScript Authsub continues redirect

  - by Krustal

  I am using the JavaScript Google Data API and having issues getting the AuthSub script to work correctly. This is my script currently: google.load('gdata', '1'); function getCookie(c_name){ if(document.cookie.length>0){ c_start=document.cookie.indexOf(c_name + "="); if(c_start!=-1){ c_start=c_start + c_name.length+1; c_end=document.cookie.indexOf(";",c_start); if(c_end==-1) c_end=document.cookie.length; return unescape(document.cookie.substring(c_start, c_end)); } } return ""; } function main(){ var scope = 'http://www.google.com/calendar/feeds/'; if(!google.accounts.user.checkLogin(scope)){ google.accounts.user.login(); } else { /* * Retrieve all calendars */ // Create the calendar service object var calendarService = new google.gdata.calendar.CalendarService('GoogleInc-jsguide-1.0'); // The default "allcalendars" feed is used to retrieve a list of all // calendars (primary, secondary and subscribed) of the logged-in user var feedUri = 'http://www.google.com/calendar/feeds/default/allcalendars/full'; // The callback method that will be called when getAllCalendarsFeed() returns feed data var callback = function(result) { // Obtain the array of CalendarEntry var entries = result.feed.entry; //for (var i = 0; i < entries.length; i++) { var calendarEntry = entries[0]; var calendarTitle = calendarEntry.getTitle().getText(); alert('Calendar title = ' + calendarTitle); //} } // Error handler to be invoked when getAllCalendarsFeed() produces an error var handleError = function(error) { alert(error); } // Submit the request using the calendar service object calendarService.getAllCalendarsFeed(feedUri, callback, handleError); } } google.setOnLoadCallback(main); However when I run this the page redirects me to the authentication page. After I authenticate it send me back to my page and then quickly sends me back to the authenticate page again. I've included alerts to check if the token is being set and it doesn't seem to be working. Has anyone has this problem?

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• Java function changing input

  - by Doodle

  I would like to go from one number to another. For example if I started at 6 and my goal was 10 I want a function that on every pass would bring me from 6 towards 10 or if I had the number 14 and my goal was 9 it would count down from 14 towards 9.So far I have (this is written in Processing a Java Api but there is essentially no difference from regualr Java, draw is just a continuous loop) int x=100; void draw(){ x=towards(x,10); println(x); } int towards(int current ,int target){ if(current!=target){ if (current <target){ current=current+1; } else { current=current-1; } } return current; } this gives me the results I would like but I would like to have everything in side of the towards() function. When I replace X with a variable it of course resets it self to the static variable. To sum it up how can I pass a variable to a function and have that variable thats been passed change on every subsequent pass. I have looked into recursion as a solution but that of just brings me to a final solution. I can pass the count to an array but wouldn't like to do that either.

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• Segmentation fault in Qt application framework

  - by yan bellavance

  this generates a segmentation fault becuase of "QColor colorMap[9]";. If I remove colorMap the segmentation fault goes away. If I put it back. It comes back. If I do a clean all then build all, it goes away. If I increase its arraysize it comes back. On the other hand if I reduce it it doesnt come back. I tired adding this array to another project and What could be happening. I am really curious to know. I have removed everything else in that class. This widget subclassed is used to promote a widget in a QMainWindow. class LevelIndicator : public QWidget { public: LevelIndicator(QWidget * parent); void paintEvent(QPaintEvent * event ); float percent; QColor colorMap[9]; int NUM_GRADS; }; the error happens inside ui_mainwindow.h at one of these lines: hpaFwdPwrLvl->setObjectName(QString::fromUtf8("hpaFwdPwrLvl")); verticalLayout->addWidget(hpaFwdPwrLvl); I know i am not providing much but I will give alink to the app. Im trying to see if anyone has a quick answer for this.

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• PDO using singleton stored as class properity

  - by Misiur

  Hi again. OOP drives me crazy. I can't move PDO to work. Here's my DB class: class DB extends PDO { public function &instance($dsn, $username = null, $password = null, $driver_options = array()) { static $instance = null; if($instance === null) { try { $instance = new self($dsn, $username, $password, $driver_options); } catch(PDOException $e) { throw new DBException($e->getMessage()); } } return $instance; } } It's okay when i do something like this: try { $db = new DB(DB_TYPE.':host='.DB_HOST.';dbname='.DB_NAME, DB_USER, DB_PASS); } catch(DBException $e) { echo $e->getMessage(); } But this: try { $db = DB::instance(DB_TYPE.':host='.DB_HOST.';dbname='.DB_NAME, DB_USER, DB_PASS); } catch(DBException $e) { echo $e->getMessage(); } Does nothing. I mean, even when I use wrong password/username, I don't get any exception. Second thing - I have class which is "heart" of my site: class Core { static private $instance; public $db; public function __construct() { if(!self::$instance) { $this->db = DB::instance(DB_TYPE.':hpost='.DB_HOST.';dbname='.DB_NAME, DB_USER, DB_PASS); } return self::$instance; } private function __clone() { } } I've tried to use "new DB" inside class, but this: $r = $core->db->query("SELECT * FROM me_config"); print_r($r->fetch()); Return nothing. $sql = "SELECT * FROM me_config"; print_r($core->db->query($sql)); I get: PDOStatement Object ( [queryString] => SELECT * FROM me_config ) I'm really confused, what am I doing wrong?

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• PHP Ampersand in String

  - by John

  Hello. I'm having a bit of a problem. I am trying to create an IRC bot, which has an ampersand in its password. However, I'm having trouble putting the ampersand in a string. For example... <?php $var = "g&abc123"; echo $var; ?> I believe this should print g&abc123. However it's printing g. I have tried this as well: <?php $arr = array("key" => "g&abc123"); print_r($arr); ?> This prints it correctly with the g&abc123, however when I say echo $arr['key']; it prints g again. Any help would be appreciated. I'm running PHP5.3.1. EDIT: Also, I just noticed that if I use g&abc123&abc123 it prints g&abc123. Any suggestions?

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• Glitch when moving camera in OpenGL

  - by CG

  I am writing a tile-based game engine for the iPhone and it works in general apart from the following glitch. Basically, the camera will always keep the player in the centre of the screen, and it moves to follow the player correctly and draws everything correctly when stationary. However whilst the player is moving, the tiles of the surface the player is walking on glitch as shown: Compared to the stationary (correct): Does anyone have any idea why this could be? Thanks for the responses so far. Floating point error was my first thought also and I tried slightly increasing the size of the tiles but this did not help. Changing glClearColor to red still leaves black gaps so maybe it isn't floating point error. Since the tiles in general will use different textures, I don't know if vertex arrays can be used (I always thought that the same texture had to be applied to everything in the array, correct me if I'm wrong), and I don't think VBO is available in OpenGL ES. Setting the filtering to nearest neighbour improved things but the glitch still happens every ten frames or so, and the pixelly result means that this solution is not viable anyway. The main difference between what I'm doing now and what I've done in the past is that this time I am moving the camera rather than the stationary objects in the world (i.e. the tiles, the player is still being moved). The code I'm using to move the camera is: void Camera::CentreAtPoint( GLfloat x, GLfloat y ) { glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrthof(x - size.x / 2.0f, x + size.x / 2.0f, y + size.y / 2.0f, y - size.y / 2.0f, 0.01f, 5.0f); glMatrixMode(GL_MODELVIEW); } Is there a problem with doing things this way and if so is there a solution?

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• List local printers

  - by vladimir

  hi all, i am using this routine to list the local printers installed on on a machine... var p: pointer; hpi: _PRINTER_INFO_2A; hGlobal: cardinal; dwNeeded, dwReturned: DWORD; bFlag: boolean; i: dword; begin p := nil; EnumPrinters(PRINTER_ENUM_LOCAL, nil, 2, p, 0, dwNeeded, dwReturned); if (dwNeeded = 0) then exit; GetMem(p,dwNeeded); if (p = nil) then exit; bFlag := EnumPrinters(PRINTER_ENUM_LOCAL, nil, 2, p, dwneeded, dwNeeded, dwReturned); if (not bFlag) then exit; CbLblPrinterPath.Properties.Items.Clear; for i := 0 to dwReturned - 1 do begin CbLblPrinterPath.Properties.Items.Add(TPrinterInfos(p^)[i].pPrinterName); end; FreeMem(p); TPrinterInfos(p^)[i].pPrinterName returns a 'P' for printer name. i have a PdfCreator installed as a printer. TPrinterInfos is an array of _PRINTER_INFO_2A. how can i fix this?

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• Glob() filesearch, question

  - by Peter

  Hi, a little question. I have this code, which is works perfect for files, but If am trying search on a directory name, the result is blank. How I can fix that? <?php function listdirs($dir,$search) { static $alldirs = array(); $dirs = glob($dir."*"); foreach ($dirs as $d){ if(is_file($d)){ $filename = pathinfo($d); if(eregi($search,$filename['filename'])){ print "<a href=http://someurl.com/" . $d .">". $d . "</a><br/>"; } }else{ listdirs($d."/",$search); } } } $path = "somedir/"; $search= "test"; listdirs($path,$search); ?> somedir/test/ result: blank (I want: /somedir/test/) somedir/test/test.txt result: OK I want to search also in the directory names, how I can do that?

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• PreparedStatement question in Java against Oracle.

  - by fardon57

  Hi everyone, I'm working on the modification of some code to use preparedStatement instead of normal Statement, for security and performance reason. Our application is currently storing information into an embedded derby database, but we are going to move soon to Oracle. I've found two things that I need your help guys about Oracle and Prepared Statement : 1- I've found this document saying that Oracle doesn't handle bind parameters into IN clauses, so we cannot supply a query like : Select pokemon from pokemonTable where capacity in (?,?,?,?) Is that true ? Is there any workaround ? ... Why ? 2- We have some fields which are of type TIMESTAMP. So with our actual Statement, the query looks like this : Select raichu from pokemonTable where evolution = TO_TIMESTAMP('2500-12-31 00:00:00.000', 'YYYY-MM-DD HH24:MI:SS.FF') What should be done for a prepared Statement ? Should I put into the array of parameters : 2500-12-31 or TO_TIMESTAMP('2500-12-31 00:00:00.000', 'YYYY-MM-DD HH24:MI:SS.FF') ? Thanks for your help, I hope my questions are clear ! Regards,

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• How to set App as site.com/ in Kohana3

  - by Drew

  Hi all! I've only just started using Kohana ( 3 hours ago), and so far it's blown my socks off (and I'm wearing slippers, so that's quite impressive). Right now, I have a controller 'Controller_FrontPage' with associated views and models and I'm trying to get it accesible from the root of my website (eg, http://www.mysite.com/). If I edit the default controller in the bootstrap from: Route::set('default', '(<controller>(/<action>(/<id>)))') ->defaults(array( 'controller' => 'welcome', 'action' => 'index', )); to 'controller' => '', I get an error, could not find controller_ (which makes sense), and if I change it to 'controller' => '/', I get an error, could not find controller_/ (which also makes sense). If I set 'controller' => 'FrontPage', everything works fine, but all my links (html::anchor(...)) point to http://www.mysite.com/FrontPage/*. Is there a way to have all the anchors point to http://www.mysite.com/*?

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• Dealing with multiple generics in a method call

  - by thaBadDawg

  I've been dealing a lot lately with abstract classes that use generics. This is all good and fine because I get a lot of utility out of these classes but now it's making for some rather ugly code down the line. For example: abstract class ClassBase<T> { T Property { get; set; } } class MyClass : ClassBase<string> { OtherClass PropertyDetail { get; set; } } This implementation isn't all that crazy, except when I want to reference the abstract class from a helper class and then I have to make a list of generics just to make reference to the implemented class, like this below. class Helper { void HelpMe<C, T>(object Value) where C : ClassBase<T>, new() { DoWork(); } } This is just a tame example, because I have some method calls where the list of where clauses end up being 5 or 6 lines long to handle all of the generic data. What I'd really like to do is class Helper { void HelpMe<C>(object Value) where C : ClassBase, new() { DoWork(); } } but it obviously won't compile. I want to reference ClassBase without having to pass it a whole array of generic classes to get the function to work, but I don't want to reference the higher level classes because there are a dozen of those. Am I the victim of my own cleverness or is there an avenue that I haven't considered yet?

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• Javascript nested functions not returning

  - by Achintha Samindika

  I'm building a phonehap application. I'm using an web sql and everything works fine till data retival. function getItemGroups(){ var items_groups = new Array(); var db = window.openDatabase("merbokDB", "1.0", "MerbokDB", 5232394); db.transaction( function(tx){ tx.executeSql('SELECT * FROM item_groups',[], function(tx,result){ if(result.rows.length > 0){ var len = result.rows.length; for (var i=0; i<len; i++){ items_groups.push(result.rows.item(i).item_group); } console.log(items_groups.join()); } } ,errorCB); }, errorCB); return items_groups; } var myproducts = getItemGroups(); My problem was when I run the code "myproducts" variable is blank. but the I can see console.log(items_groups.join()); following line printing the values in console. Is I'm wrong in the way I returning?

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• PHP and MySQL validating problem

  - by IPADvsSLATE

  I'm trying to check if a color is already entered into the database if it is the color should not be entered and stored into the database and the following error code <p>This color has already been entered!</p> should be displayed. But for some reason I cant get this to work, can someone please help me? The color names are entered into $_POST['color'] which is an array entered by the user. Here is the html code that collects the colors. <input type="text" name="color[]" /> <input type="text" name="color[]" /> <input type="text" name="color[]" /> <input type="text" name="color[]" /> <input type="text" name="color[]" /> <input type="text" name="color[]" /> <input type="text" name="color[]" /> <input type="text" name="color[]" /> <input type="text" name="color[]" /> Here is the PHP & MySQL code. for($i=0; $i < count($_POST['color']); $i++) { $color = "'" . $_POST['color'][$i] . "'"; } $mysqli = mysqli_connect("localhost", "root", "", "sitename"); $dbc = mysqli_query($mysqli,"SELECT * FROM colors WHERE color = '$color' AND user = '$user_id' "); if(mysqli_num_rows($dbc) == TRUE) { echo '<p>This color has already been entered!</p>'; } else if(mysqli_num_rows($dbc) == 0) { // enter the color into the database }

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• inserting unique date into txt document

  - by durian

  I'm trying this script to insert only a unique date into a text file, but it isn't working properly: $log_file_name = "logfile.txt"; $log_file_path = "log_files/$id/$log_file_name"; if(file_exists($log_file_path)){ $not = "not"; $todaydate = date('d,m,Y'); $today = "$todaydate;"; $strlength = strlen($today); $file_contents = file_get_contents($log_file_path); $file_contents_arry = explode(";",$file_contents); if(!in_array($todaytodaydate,$file_contents_arry)){ $append = fopen($log_file_path, 'a'); $write = fwrite($append,$today); //writes our string to our file. $close = fclose($append); //closes our file } else { $append = fopen($log_file_path, 'a'); $write = fwrite($append,$not); //writes our string to our file. $close = fclose($append); //closes our file } } else{ mkdir("log_files/$id", 0700); $todaydate = date('d,m,Y'); $today = "$todaydate;"; $strlength = strlen($today); $create = fopen($log_file_path, "w"); $write = fwrite($create, $today, $strlength); //writes our string to our file. $close = fclose($create); //closes our file } The problem is with the if else statement where it should be written if it's already in the array.

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• Weird character at start of json content type

  - by Nek

  Hi, I'm trying to return json content read from MySQL server. This is supposed to be easy but, there is a 'weird' character that keeps appearing at start of the content. I have two pages for returning content: kcb433.sytes.net/as/test.php?json=true&limit=6&input=d this test.php is from a script written by Timothy Groves, which converts an array to json output http://kcb433.sytes.net/k.php?k=4 this one is supposed to do the same I tried to validate it here jsonformatter.curiousconcept.com but just page 1 gets validated, page 2 says that it does not contain JSON data. If accessed directly both pages has no problems. Then what is the difference, why both don't get validated? Then I found this page jsonformat.com and tried the same thing. Page 1 was ok and page 2 wasn't but, surprisingly the data could be read. At a glance, {"a":"b"} may look good but there is a character in front. According to a hex editor online, this is the value of the string above (instead of 9 values, there are 10): -- 7B 22 61 22 3A 22 62 22 7D The code to echo json in page 2 is: header("Content-Type: application/json"); echo "{\"a\":\"b\"}";

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• Parallel.For Batching

  - by chibacity

  Is there built-in support in the TPL for batching operations? I was recently playing with a routine to carry out character replacement on a character array which required a lookup table i.e. transliteration: for (int i = 0; i < chars.Length; i++) { char replaceChar; if (lookup.TryGetValue(chars[i], out replaceChar)) { chars[i] = replaceChar; } } I could see that this could be trivially parallelized, so jumped in with a first stab which I knew would perform worse as the tasks were too fine-grained: Parallel.For(0, chars.Length, i => { char replaceChar; if (lookup.TryGetValue(chars[i], out replaceChar)) { chars[i] = replaceChar; } }); I then reworked the algorithm to use batching so that the work could be chunked onto different threads in less fine-grained batches. This made use of threads as expected and I got some near linear speed up. I'm sure that there must be built-in support for batching in the TPL. What is the syntax, and how do I use it? const int CharBatch = 100; int charLen = chars.Length; Parallel.For(0, ((charLen / CharBatch) + 1), i => { int batchUpper = ((i + 1) * CharBatch); for (int j = i * CharBatch; j < batchUpper && j < charLen; j++) { char replaceChar; if (lookup.TryGetValue(chars[j], out replaceChar)) { chars[j] = replaceChar; } } });

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• Fast way to manually mod a number

  - by Nikolai Mushegian

  I need to be able to calculate (a^b) % c for very large values of a and b (which individually are pushing limit and which cause overflow errors when you try to calculate a^b). For small enough numbers, using the identity (a^b)%c = (a%c)^b%c works, but if c is too large this doesn't really help. I wrote a loop to do the mod operation manually, one a at a time: private static long no_Overflow_Mod(ulong num_base, ulong num_exponent, ulong mod) { long answer = 1; for (int x = 0; x < num_exponent; x++) { answer = (answer * num_base) % mod; } return answer; } but this takes a very long time. Is there any simple and fast way to do this operation without actually having to take a to the power of b AND without using time-consuming loops? If all else fails, I can make a bool array to represent a huge data type and figure out how to do this with bitwise operators, but there has to be a better way.

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• Efficient algorithm for Next button on a MySQL result set

  - by David Grayson

  I have a website that lets people view rows in a table (each row is a picture). There are more than 100,000 rows. You can view different subsets of the rows, and you can view them with different sort orders. While you are viewing one of the rows, you can click the "Next" or "Previous" buttons to go the next/previous row in the list. How would you implement the "Next" and "Previous" features of the website? More specifically, if you have an arbitrary query that returns a list of up to 100,000+ rows, and you know some information about the current row someone is viewing, how do you determine the NEXT row efficiently? Here is the pseudo-code of the solution I came up with when the website was young, and it worked well when there were only 1000 rows, but now that there are 100,000 rows I think it is eating up too much memory. int nextRowId(string query, int currentRowId) { array allRowIds = mysql_query(query); // Takes up a lot of memory! int currentIndex = (index of currentRowId in allRowIds); // Takes time! return allRowIds[currentIndex+1]; } While you are thinking about this problem, remember that the website can store more information about the current row than just its ID (for example, the position of the current row in the result set), and this information can be used as a hint to help determine the ID of the next row. Edit: Sorry for not mentioning this earlier, but this isn't just a static website: rows can often be added to the list, and rows can be re-ordered in the list. (Much rarer, rows can be removed from the list.) I think that I should worry about that kind of thing, but maybe you can convince me otherwise.

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