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  • PHP -- automatic SQL injection protection?

    - by ashgromnies
    I took over maintenance of a PHP app recently and I'm not super familiar with PHP but some of the things I've been seeing on the site are making me nervous that it could be vulnerable to a SQL injection attack. For example, see how this code for logging into the administrative section works: $password = md5(HASH_SALT . $_POST['loginPass']); $query = "SELECT * FROM `administrators` WHERE `active`='1' AND `email`='{$_POST['loginEmail']}' AND `password`='{$password}'"; $userInfo = db_fetch_array(db_query($query)); if($userInfo['id']) { $_SESSION['adminLoggedIn'] = true; // user is logged in, other junk happens here, not important The creators of the site made a special db_query method and db_fetch_array method, shown here: function db_query($qstring,$print=0) { return @mysql(DB_NAME,$qstring); } function db_fetch_array($qhandle) { return @mysql_fetch_array($qhandle); } Now, this makes me think I should be able to do some sort of SQL injection attack with an email address like: ' OR 'x'='x' LIMIT 1; and some random password. When I use that on the command line, I get an administrative user back, but when I try it in the application, I get an invalid username/password error, like I should. Could there be some sort of global PHP configuration they have enabled to block these attacks? Where would that be configured? Here is the PHP --version information: # php --version PHP 5.2.12 (cli) (built: Feb 28 2010 15:59:21) Copyright (c) 1997-2009 The PHP Group Zend Engine v2.2.0, Copyright (c) 1998-2009 Zend Technologies with the ionCube PHP Loader v3.3.14, Copyright (c) 2002-2010, by ionCube Ltd., and with Zend Optimizer v3.3.9, Copyright (c) 1998-2009, by Zend Technologies

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  • Why do Scala maps have poor performance relative to Java?

    - by Mike Hanafey
    I am working on a Scala app that consumes large amounts of CPU time, so performance matters. The prototype of the system was written in Python, and performance was unacceptable. The application does a lot with inserting and manipulating data in maps. Rex Kerr's Thyme was used to look at the performance of updating and retrieving data from maps. Basically "n" random Ints were stored in maps, and retrieved from the maps, with the time relative to java.util.HashMap used as a reference. The full results for a range of "n" are here. Sample (n=100,000) performance relative to java, smaller is worse: Update Read Mutable 16.06% 76.51% Immutable 31.30% 20.68% I do not understand why the scala immutable map beats the scala mutable map in update performance. Using the sizeHint on the mutable map does not help (it appears to be ignored in the tested implementation, 2.10.3). Even more surprisingly the immutable read performance is worse than the mutable read performance, more significantly so with larger maps. The update performance of the scala mutable map is surprisingly bad, relative to both scala immutable and plain Java. What is the explanation?

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  • barebones sort algorithm

    - by user309322
    i have been asked to make a simple sort aglorithm to sort a random series of 6 numbers into numerical order. However i have been asked to do this using "Barebones" a theoretical language put forward in the Book Computer Science an overview. Some information on the language can be found here http://www.brouhaha.com/~eric/software/barebones/ Just to clarify i am a student teacher and have been doing anaysis on "mini-programing languages" and their uses in a teaching environment, i suggested to my tutor that i look at barebones and asked what sort of exmaple program i should write . He suggested a simple sort algorithm. Now since looking at the language i cant understand how i can do this without using arrays and if statements. The code to swap the value of variables would be while a not 0 do; incr Aux1; decr a; end; while b not 0 do; incr Aux2 decr b end; while Aux1 not 0 do; incr a; decr Aux1; end; while Aux2 not 0 do; incr b; decr Aux2; end; however the language does not provide < or operators

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  • Cant print contents of a custom file

    - by ZaZu
    Hello, Im trying to scan contents from a random file into an array in a structure. Then I want to print those contents on screen. (NOTE: The following code is from a bigger program, this is just a sample, but all structures and arrays used are needed as declared ) The contents of the file being tested are simply: 5 4 3 2 5 3 4 2 #include<stdio.h> #define first 500 #define sec 500 struct trial{ int f; int r; float what[first][sec]; }; int trialtest(trial *test); int trialdisplay(trial *test); main(){ trial test; trialtest(&test); trialdisplay(&test); } int trialtest(trial *test){ int z,x,i; FILE *inputf; inputf=fopen("randomfile.txt","r"); for(i=0;i<5;i++){ fscanf(inputf,"%f",&(*test).what[z][x]); } fclose(inputf); return 0; } int trialdisplay(trial *test){ int i,z,x; printf("printing\n\n\n"); for (i=0;i<10;i++){ printf("%f",(*test).what[z][x]); } return 0; } The problem is, I get this error whenever I run the code .. I cant really understand whats going on : Any suggestions ? Thanks alot !

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  • How do you organise multiple git repositories?

    - by dbr
    With SVN, I had a single big repository I kept on a server, and checked-out on a few machines. This was a pretty good backup system, and allowed me easily work on any of the machines. I could checkout a specific project, commit and it updated the 'master' project, or I could checkout the entire thing. Now, I have a bunch of git repositories, for various projects, several of which are on github. I also have the SVN repository I mentioned, imported via the git-svn command.. Basically, I like having all my code (not just projects, but random snippets and scripts, some things like my CV, articles I've written, websites I've made and so on) in one big repository I can easily clone onto remote machines, or memory-sticks/harddrives as backup. The problem is, since it's a private repository, and git doesn't allow checking out of a specific folder (that I could push to github as a separate project, but have the changes appear in both the master-repo, and the sub-repos) I could use the git submodule system, but it doesn't act how I want it too (submodules are pointers to other repositories, and don't really contain the actual code, so it's useless for backup) Currently I have a folder of git-repos (for example, ~/code_projects/proj1/.git/ ~/code_projects/proj2/.git/), and after doing changes to proj1 I do git push github, then I copy the files into ~/Documents/code/python/projects/proj1/ and do a single commit (instead of the numerous ones in the individual repos). Then do git push backupdrive1, git push mymemorystick etc So, the question: How do your personal code and projects with git repositories, and keep them synced and backed-up?

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  • increase number of photos from flickr using json

    - by Andrew Welch
    Hi this is my code: Is is possible to get more photos from flickr. What is the standard / default number? $(document).ready(function(){ $.getJSON("http://api.flickr.com/services/feeds/photos_public.gne?id=48719970@N07&lang=en-us&format=json&jsoncallback=?", function(data){ $.each(data.items, function(i, item){ var newurl = 'url(' + item.media.m + ')'; $("<div class='images'/>").css('background', newurl).css('backgroundPosition','top center').css('backgroundRepeat','no-repeat').appendTo("#images").wrap("<a target=\"_blank\ href='" + item.link + "'></a>"); }) $("#title").html(data.title); $("#description").html(data.description); $("#link").html("<a href='" + data.link + "' target=\"_blank\">Visit the Viget Inspiration Pool!</a>"); //Notice that the object here is "data" because that information sits outside of "items" in the JSON feed $('.jcycleimagecarousel').cycle({ fx: 'fade', speed: 300, timeout: 3000, next: '#next', prev: '#prev', pause: 1, random: 1 }); }); });

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  • Extract history from Korn shell

    - by Luc
    I am not happy about the history file in binary format of the Korn shell. I like to "collect" some of my command lines, many of them actually, and for a long time. I'm talking about years. That doesn't seem easy in Korn because the history file is not plain text so I can't edit it, and a lot of junk is piling up in it. By "junk" I mean lines that I don'twant to keep, like 'cat' or 'man'. So I added these lines to my .profile: fc -ln 1 9999 ~/khistory.txt source ~/loghistory.sh ~/khistory.txt loghistory.sh contains a handful of sed and sort commands that gets rid of a lot of the junk. But apparently it is forbidden to run fc in the .profile file. I can't login whenever I do, the shell exits right away with signal 11. So I removed that 'fc -l' line from my .profile file and added it to the loghistory.sh script, but the shell still crashes. I also tried this line in my .profile: strings ~/.sh_history ~/khistory.txt source ~/loghistory.sh That doesn't crash, but the output is printed with an additional, random character in the beginning of many lines. I can run 'fc -l' on the command line, but that's no good. I need to automate that. But how? How can I extract my ksh history as plain text? TIA

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  • Am I going the right way to make login system secure with this simple password salting?

    - by LoVeSmItH
    I have two fields in login table password salt And I have this little function to generate salt function random_salt($h_algo="sha512"){ $salt1=uniqid(rand(),TRUE); $salt2=date("YmdHis").microtime(true); if(function_exists('dechex')){ $salt2=dechex($salt2); } $salt3=$_SERVER['REMOTE_ADDR']; $salt=$salt1.$salt2.$salt3; if(function_exists('hash')){ $hash=(in_array($h_algo,hash_algos()))?$h_algo:"sha512"; $randomsalt=hash($hash,md5($salt)); //returns 128 character long hash if sha512 algorithm is used. }else{ $randomsalt=sha1(md5($salt)); //returns 40 characters long hash } return $randomsalt; } Now to create user password I have following $userinput=$_POST["password"] //don't bother about escaping, i have done it in my real project. $static_salt="THIS-3434-95456-IS-RANDOM-27883478274-SALT"; //some static hard to predict secret salt. $salt=random_salt(); //generates 128 character long hash. $password =sha1($salt.$userinput.$static_salt); $salt is saved in salt field of database and $password is saved in password field. My problem, In function random_salt(), I m having this FEELING that I'm just making things complicated while this may not generate secure salt as it should. Can someone throw me a light whether I m going in a right direction? P.S. I do have an idea about crypt functions and like such. Just want to know is my code okay? Thanks.

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  • How to (kindly) ask your users to upgrade from IE6?

    - by nickf
    It's no secret at all that IE6 has been a major roadblock to the advancement of the web over the last few years. I couldn't count the number of hours I've spent bashing my head against a wall trying to fix or debug IE6 issues. The way I see it, there are two types of IE6 user. a) the poor corporate schmoe whose IT department doesn't want to upgrade in case something breaks, and b) the mums and dads of the world who think the internet is the blue E on their desktop (and I don't mean that in a nasty way). There's probably a couple of people who know about all the other browsers, but still choose to run IE6. They get what they deserve, IMO. Anyway, getting to the point, I'd say that 90% of my IE6-using visitors are in the the mums and dads category - they're not stupid, they just don't know WHY they should upgrade to IE7 or Firefox or whatever. How do I educate these people without pissing them off? Is there a nice and friendly website I can direct these people to, which explains the reasons for upgrading in plain language? Any mention of "security" or "web standards" I think would just come across as scary. I've just seen http://www.whatbrowser.org which seems to fit the bill nicely. It explains in very basic terms: what a web browser is why you'd want to upgrade it how old your current browser is (subtle hint to those with a 9 year old browser) ..aaaand it's in 22 languages. It's from Google but displays no bias (it links to Firefox, Chrome, Opera, Safari, Internet Explorer displayed in a random order).

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  • Looking for a 'pick a-or-b' voting system script

    - by user324455
    Apologies: this is my first time on stackoverflow and I'm starting with a question and seeking advice. Sorry. Caveats: I know HTML and CSS pretty well. Javascript and PHP are not completely alien, but I'm really pretty basic on those. That said, I'm pretty sharp and willing to search for explanations independently. Ok, so my question is this: I want to create a site with a voting system very much like the one on kittenwar.com - the page loads 2 random images from a db of some sort and you click on the one you want to 'win'. Ranked pairs kind of deal. Then there is a leaderboard of those images which have the highest win-loss ratio. There also needs to be an uploader for peeps to upload their own images and have them go into an approval workflow, and from there into the db that feeds the voting thing. I tried a pre-made solution ('photo battle') but found it was completely standalone, so trying to integrate it or change any of the options was a nightmare, plus it was buggy. i'm sure there has to be a relatively easy way to do this, right? Ideally I'd like to build my site in Joomla and integrate this functionality somehow. I'd be very grateful for any advice on this. Thanks Tom

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  • Is sending a hashed password over the wire a security hole?

    - by Ubiquitous Che
    I've come across a system that is in use by a company that we are considering partnering with on a medium-sized (for us, not them) project. They have a web service that we will need to integrate with. My current understanding of proper username/password management is that the username may be stored as plaintext in the database. Every user should have a unique pseudo-random salt, which may also be stored in plaintext. The text of their password must be concatenated with the salt and then this combined string may be hashed and stored in the database in an nvarchar field. So long as passwords are submitted to the website (or web service) over plaintext, everything should be just lovely. Feel free to rip into my understanding as summarized above if I'm wrong. Anyway, back to the subject at hand. The WebService run by this potential partner doesn't accept username and password, which I had anticipated. Instead, it accepts two string fields named 'Username' and 'PasswordHash'. The 'PasswordHash' value that I have been given does indeed look like a hash, and not just a value for a mis-named password field. This is raising a red flag for me. I'm not sure why, but I feel uncomfortable sending a hashed password over the wire for some reason. Off the top of my head I can't think of a reason why this would be a bad thing... Technically, the hash is available on the database anyway. But it's making me nervous, and I'm not sure if there's a reason for this or if I'm just being paranoid.

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  • static variable lose its value

    - by user542719
    I have helper class with this static variable that is used for passing data between two classes. public class Helper{ public static String paramDriveMod;//this is the static variable in first calss } this variable is used in following second class mathod public void USB_HandleMessage(char []USB_RXBuffer){ int type=USB_RXBuffer[2]; MESSAGES ms=MESSAGES.values()[type]; switch(ms) { case READ_PARAMETER_VALUE: // read parameter values switch(prm){ case PARAMETER_DRIVE_MODE: // paramet drive mode Helper.paramDriveMod =(Integer.toString(((USB_RXBuffer[4]<< 8)&0xff00))); System.out.println(Helper.paramDriveMod+"drive mode is selectd ");//here it shows the value that I need. ..........}}//let say end switch and method and the following is an third class method use the above class method public void buttonSwitch(int value) throws InterruptedException{ boolean bool=true; int c=0; int delay=(int) Math.random(); while(bool){ int param=3; PARAMETERS prm=PARAMETERS.values()[param]; switch(value){ case 0: value=1; while(c<5){ Thread.sleep(delay); protocol.onSending(3,prm.PARAMETER_DRIVE_MODE.ordinal(),dataToRead,dataToRead.length);//read drive mode System.out.println(Helper.paramDriveMod+" drive mode is ..........in wile loop");//here it shows null value }}//let say end switch and method what is the reason that this variable lose its value?

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  • How to map a test onto a list of numbers

    - by Arthur Ulfeldt
    I have a function with a bug: user> (-> 42 int-to-bytes bytes-to-int) 42 user> (-> 128 int-to-bytes bytes-to-int) -128 user> looks like I need to handle overflow when converting back... Better write a test to make sure this never happens again. This project is using clojure.contrib.test-is so i write: (deftest int-to-bytes-to-int (let [lots-of-big-numbers (big-test-numbers)] (map #(is (= (-> % int-to-bytes bytes-to-int) %)) lots-of-big-numbers))) This should be testing converting to a seq of bytes and back again produces the origional result on a list of 10000 random numbers. Looks OK in theory? except none of the tests ever run. Testing com.cryptovide.miscTest Ran 23 tests containing 34 assertions. 0 failures, 0 errors. why don't the tests run? what can I do to make them run?

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  • struct and rand()

    - by teoz
    I have a struct with an array of 100 int (b) and a variable of type int (a) I have a function that checks if the value of "a" is in the array and i have generated the array elements and the variable with random values. but it doesn't work can someone help me fix it? #include <stdio.h> #include <stdlib.h> #include <time.h> typedef struct { int a; int b[100]; } h; int func(h v){ int i; for (i=0;i<100;i++){ if(v.b[i]==v.a) return 1; else return 0; } } int main(int argc, char** argv) { h str; srand(time(0)); int i; for(i=0;0<100;i++){ str.b[i]=(rand() % 10) + 1; } str.a=(rand() % 10) + 1; str.a=1; printf("%d\n",func(str)); return 0; }

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  • Android: Capturing the return of an activity.

    - by Chrispix
    I have a question regarding launching new activities. It boils down to this. I have 3 tabs on a view A) contains gMap activity B) camera activity C) some random text fields. Requirement is that the application runs in Portrait mode. All 3 tabs work as expected w/ the exception of the Camera Preview Surface (B). It is rotated 90 degrees. They only way to make it correct is to set the app to landscape which throws all my tabs around, and is pretty much unworkable. My solution is this : replace my camera activity with a regular activity that is empty w/ the exception of Intent i = new Intent(this,CameraActivity.class); startActivity(i); This launches my CameraActivity. And that works fine. I had to do a linear layout and include 3 images that look like real tabs, so I can try and mimic the operation of the tabs while rotating the screen to landscape and keep the visuals as portrait. The user can click one of the images(buttons) to display the next tab. This is my issue. It should exit my 'camera activity' returning to the 'blank activity' in a tab, where it should be interpreted to click the desiered tab from my image. The main thing is, when it returns, it returns to a blank (black) page under a tab (because it is 'empty'). How can I capture the return event back to the page that called the activity, and then see what action they performed? I can set an onclicklistener where I can respond to the fake tabs (images) being clicked to exit out of the camera activity. On exit, the tab should update so that is where you return. any Suggestions? Thanks,

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  • What is the best Design/Way to keep user connected ?

    - by Fasih Hansmukh
    Am working on a POC for self learning in which I want to keep my user connected in LIVE pattern. For example, A game in which 4 user can play at a time , here I need to keep this user connected to my game . M not good at Socket type of programming and love to do that in Services way.What i wana know is 'What is the best way of doing this'. According to my initial Brain Storming, I have decided that I will use SilverLight(In Browser Or Out of Browser) as Front end [I have no issue in that]. I m more concern in back end. Either I make an handler or make a WCF service or use full duplex service and use pooling mechanism for that. As a random thought I come up with a Timer type logic that will fire every after 10 seconds at clients end and get status like Is it now Its turn to roll a dice Home many user left (in case if some of them left) What are connected user status in game like there score/points ect and update game view according to this at his end Kindly place your best answers here that will help me to learn this. Regards and thanks in Advance EDIT: Starting Bounty as i need more feedback. FH

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  • WSACONNREFUSED when connecting to server

    - by Robert Mason
    I'm currently working on a server. I know that the client side is working (I can connect to www.google.com on port 80, for example), but the server is not functioning correctly. The socket has socket()ed, bind()ed, and listen()ed successfully and is on an accept loop. The only problem is that accept() doesn't seem to work. netstat shows that the server connection is running fine, as it prints the PID of the server process as LISTENING on the correct port. However, accept never returns. Accept just keeps running, and running, and if i try to connect to the port on localhost, i get a 10061 WSACONNREFUSED. I tried looping the connection, and it just keeps refusing connections until i hit ctrl+c. I put a breakpoint directly after the call to accept(), and no matter how many times i try to connect to that port, the breakpoint never fires. Why is accept not accepting connections? Has anyone else had this problem before? Known: [breakpoint0] if ((new_fd = accept(sockint, NULL, NULL)) == -1) { throw netlib::error("Accept Error"); //netlib::error : public std::exception } else { [breakpoint1] code...; } breakpoint0 is reached (and then continued through), no exception is thrown, and breakpoint1 is never reached. The client code is proven to work. Netstat shows that the socket is listening. If it means anything, i'm connecting to 127.0.0.1 on port 5842 (random number). The server is configured to run on 5842, and netstat confirms that the port is correct.

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  • Save Xml in an Excel cell value causes ComException

    - by mas_oz2k1
    I am trying to save an object (Class1) as string in a cell value. My issue is that from time to time I have a ComException: HRESULT: 0x8007000E (E_OUTOFMEMORY) (It is kind of random but I have not identified any particular pattern yet) when I write the value into a cell. Any ideas will be welcome For illustration purposes: Let Class1 be the class to be converted to an Xml string. (Notice that I removed the xml declaration at the start of the string to avoid having the preamble present- non printable character) <Class1 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" <ElementID HL690375</ElementID </Class1" Class1 myClass = new Class1(); this class is converted to a string s. s= ConvertObjectToXmlString(myClass); then s is assigned to a cell Range r = Application.ActiveCell; r.Value2 = s; Note: (1) If the string is too big, I limit it to 32000 chars and split the string in chunks of 32000 chars and save the chunks in multiple cells. (2) I do not to quote the string before adding to a cell. Do I need to? If so how it can be done? (3) All object contents are English. (4) C# code sample will be great but VB.net code is OK.

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  • Java Concurrency in practice sample question

    - by andy boot
    I am reading "Java Concurrency in practice" and looking at the example code on page 51. This states that if a thread has references to a shared object then other threads may be able to access that object before the constructor has finished executing. I have tried to put this into practice and so I wrote this code thinking that if I ran it enough times a RuntimeException("World is f*cked") would occur. But it isn't doing. Is this a case of the Java spec not guaranting something but my particular implementation of java guaranteeing it for me? (java version: 1.5.0 on Ubuntu) Or have I misread something in the book? Code: (I expect an exception but it is never thrown) public class Threads { private Widgit w; public static void main(String[] s) throws Exception { while(true){ Threads t = new Threads(); t.runThreads(); } } private void runThreads() throws Exception{ new Checker().start(); w = new Widgit((int)(Math.random() * 100) + 1); } private class Checker extends Thread{ private static final int LOOP_TIMES = 1000; public void run() { int count = 0; for(int i = 0; i < LOOP_TIMES; i++){ try { w.checkMe(); count++; } catch(NullPointerException npe){ //ignore } } System.out.println("checked: "+count+" times out of "+LOOP_TIMES); } } private static class Widgit{ private int n; private int n2; Widgit(int n) throws InterruptedException{ this.n = n; Thread.sleep(2); this.n2 = n; } void checkMe(){ if (n != n2) { throw new RuntimeException("World is f*cked"); } } } }

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  • Find all ways to insert zeroes into a bit pattern

    - by James
    I've been struggling to wrap my head around this for some reason. I have 15 bits that represent a number. The bits must match a pattern. The pattern is defined in the way the bits start out: they are in the most flush-right representation of that pattern. So say the pattern is 1 4 1. The bits will be: 000000010111101 So the general rule is, take each number in the pattern, create that many bits (1, 4 or 1 in this case) and then have at least one space separating them. So if it's 1 2 6 1 (it will be random): 001011011111101 Starting with the flush-right version, I want to generate every single possible number that meets that pattern. The # of bits will be stored in a variable. So for a simple case, assume it's 5 bits and the initial bit pattern is: 00101. I want to generate: 00101 01001 01010 10001 10010 10100 I'm trying to do this in Objective-C, but anything resembling C would be fine. I just can't seem to come up with a good recursive algorithm for this. It makes sense in the above example, but when I start getting into 12431 and having to keep track of everything it breaks down.

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  • Display two array's in the same table

    - by Naeem Ahmed
    $row = $query->fetchAll(PDO::FETCH_ASSOC); $num_rows = count($row); for ($i = 0; $i < $num_rows; $i++) { $title = htmlspecialchars($row[$i]['title']); $author =htmlspecialchars($row[$i]['author']); $school =htmlspecialchars($row[$i]['school']); $solution = $row[$i]['solution']; $notes = $row[$i]['notes']; $ad = array($title, $price, $author, $school, $contact, $content, $date); $inlcude = array($solutions, $notes); $field = 0; echo "<table border='1'>"; // foreach($inlcude as $in) This failled miserably foreach ($ad as $post) { if ($field < 3) //The first three values are placed in the first row { echo "<td>$post</td>"; } if ($field >= 3) { echo "<tr><td>$post</td><td>$in</td></tr>"; } $field++; } echo '</table>'; } I have two arrays and I would like to display them in different columns in my table. $ad displays perfectly fine but I'm having trouble displaying the contents in $inlcude in the second column. I've tried putting another foreach loop to iterate through contents of the second array but that really screws up my table by placing random values in different places on the table. Besides the foreach loop, I don't know of any other way to iterate through the array. Any suggestions would be appreciated.Thanks!

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  • Best practices for encrypting continuous/small UDP data

    - by temp
    Hello everyone, I am having an application where I have to send several small data per second through the network using UDP. The application need to send the data in real-time (no waiting). I want to encrypt these data and insure that what I am doing is as secure as possible. Since I am using UDP, there is no way to use SSL/TLS, so I have to encrypt each packet alone since the protocol is connectionless/unreliable/unregulated. Right now, I am using a 128-bit key derived from a passphrase from the user, and AES in CBC mode (PBE using AES-CBC). I decided to use a random salt with the passphrase to derive the 128-bit key (prevent dictionary attack on the passphrase), and of course use IVs (to prevent statistical analysis for packets). However I am concerned about few things: Each packet contains small amount of data (like a couple of integer values per packet) which will make the encrypted packets vulnerable to known-plaintext attacks (which will result in making it easier to crack the key). Also, since the encryption key is derived from a passphrase, this will make the key space way less (I know the salt will help, but I have to send the salt through the network once and anyone can get it). Given these two things, anyone can sniff and store the sent data, and try to crack the key. Although this process might take some time, once the key is cracked all the stored data will be decrypted, which will be a real problem for my application. So my question is, what is the best practices for sending/encrypting continuous small data using a connectionless protocol (UDP)? Is my way the best way to do it? ...flowed? ...Overkill? ... Please note that I am not asking for a 100% secure solution, as there is no such thing. Cheers

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  • Largest triangle from a set of points

    - by Faken
    I have a set of random points from which i want to find the largest triangle by area who's verticies are each on one of those points. So far I have figured out that the largest triangle's verticies will only lie on the outside points of the cloud of points (or the convex hull) so i have programmed a function to do just that (using Graham scan in nlogn time). However that's where I'm stuck. The only way I can figure out how to find the largest triangle from these points is to use brute force at n^3 time which is still acceptable in an average case as the convex hull algorithm usually kicks out the vast majority of points. However in a worst case scenario where points are on a circle, this method would fail miserably. Dose anyone know an algorithm to do this more efficiently? Note: I know that CGAL has this algorithm there but they do not go into any details on how its done. I don't want to use libraries, i want to learn this and program it myself (and also allow me to tweak it to exactly the way i want it to operate, just like the graham scan in which other implementations pick up collinear points that i don't want).

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  • Checking if an SSH tunnel is up and running

    - by Jarmund
    I have a perl script which, when destilled a bit, looks like this: my $randport = int(10000 + rand(1000)); # Random port as other scripts like this run at the same time my $localip = '192.168.100.' . ($port - 4000); # Don't ask... backwards compatibility system("ssh -NL $randport:$localip:23 root\@$ip -o ConnectTimeout=60 -i somekey &"); # create the tunnel in the background sleep 10; # Give the tunnel some time to come up # Create the telnet object my $telnet = new Net::Telnet( Timeout => 10, Host => 'localhost', Port => $randport, Telnetmode => 0, Errmode => \&fail, ); # SNIPPED... a bunch of parsing data from $telnet The thing is that the target $ip is on a link with very unpredictable bandwidth, so the tunnel might come up right away, it might take a while, it might not come up at all. So a sleep is necessary to give the tunnel some time to get up and running. So the question is: How can i test if the tunnel is up and running? 10 seconds is a really undesirable delay if the tunnel comes up straight away. Ideally, i would like to check if it's up and continue with creating the telnet object once it is, to a maximum of, say, 30 seconds.

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  • How to maintain ComboBox.SelectedItem reference when DataSource is resorted?

    - by Dave
    This really seems like a bug to me, but perhaps some databinding gurus can enlighten me? (My WinForms databinding knowledge is quite limited.) I have a ComboBox bound to a sorted DataView. When the properties of the items in the DataView change such that items are resorted, the SelectedItem in my ComboBox does not keep in-sync. It seems to point to someplace completely random. Is this a bug, or am I missing something in my databinding? Here is a sample application that reproduces the problem. All you need is a Button and a ComboBox: public partial class Form1 : Form { private DataTable myData; public Form1() { this.InitializeComponent(); this.myData = new DataTable(); this.myData.Columns.Add("ID", typeof(int)); this.myData.Columns.Add("Name", typeof(string)); this.myData.Columns.Add("LastModified", typeof(DateTime)); this.myData.Rows.Add(1, "first", DateTime.Now.AddMinutes(-2)); this.myData.Rows.Add(2, "second", DateTime.Now.AddMinutes(-1)); this.myData.Rows.Add(3, "third", DateTime.Now); this.myData.DefaultView.Sort = "LastModified DESC"; this.comboBox1.DataSource = this.myData.DefaultView; this.comboBox1.ValueMember = "ID"; this.comboBox1.DisplayMember = "Name"; } private void saveStuffButton_Click(object sender, EventArgs e) { DataRowView preUpdateSelectedItem = (DataRowView)this.comboBox1.SelectedItem; // OUTPUT: SelectedIndex = 0; SelectedItem.Name = third Debug.WriteLine(string.Format("SelectedIndex = {0:N0}; SelectedItem.Name = {1}", this.comboBox1.SelectedIndex, preUpdateSelectedItem["Name"])); this.myData.Rows[0]["LastModified"] = DateTime.Now; DataRowView postUpdateSelectedItem = (DataRowView)this.comboBox1.SelectedItem; // OUTPUT: SelectedIndex = 2; SelectedItem.Name = second Debug.WriteLine(string.Format("SelectedIndex = {0:N0}; SelectedItem.Name = {1}", this.comboBox1.SelectedIndex, postUpdateSelectedItem["Name"])); // FAIL! Debug.Assert(object.ReferenceEquals(preUpdateSelectedItem, postUpdateSelectedItem)); } }

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