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  • vi issue in SSH TTYs to Ubuntu 14.04.1 LTS

    - by Steve Campbell
    After upgrading my server to Ubuntu 14.04.1 LTS, I can no longer use the vi editor to edit anything in an SSH terminal (I access the server by launching ssh sessions from Cygwin running on Windows). The empty portions of the vi window fill with garbage. The workaround is to launch an xterm from the server back to my Cygwin/X display. Using vi from within the xterm works fine. Setting my TERM to vt100/vt220/xterm does not help.

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  • Hash Sum Mismatch using preseed (Ubuntu Server 12.04)

    - by xorma
    My install through Preseed fails at around 80% on Select and Install Software. In VT-4, I can see Hash Sum mismatch errors. This may be because I am going through a firewall which is caching files. There is no-cache option for apt but I can't seem to get it to work with Preseed. Have tried: d-i debian-installer/no-cache string true d-i apt-setup/no-cache boolean true d-i preseed/early_command string mkdir -p /target/etc/apt/apt.conf.d; echo "Acquire::http {No-Cache=True;};" > /target/etc/apt/apt.conf.d/no-cache but none of these are working. It appears that the early_command occurs too early so is over written once install starts. I'm not sure if the other commands are even correct. Anyone know what is the correct way of disabling achieving this through Preseed?

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  • How to store Role Based Access rights in web application?

    - by JonH
    Currently working on a web based CRM type system that deals with various Modules such as Companies, Contacts, Projects, Sub Projects, etc. A typical CRM type system (asp.net web form, C#, SQL Server backend). We plan to implement role based security so that basically a user can have one or more roles. Roles would be broken down by first the module type such as: -Company -Contact And then by the actions for that module for instance each module would end up with a table such as this: Role1 Example: Module Create Edit Delete View Company Yes Owner Only No Yes Contact Yes Yes Yes Yes In the above case Role1 has two module types (Company, and Contact). For company, the person assigned to this role can create companies, can view companies, can only edit records he/she created and cannot delete. For this same role for the module contact this user can create contacts, edit contacts, delete contacts, and view contacts (full rights basically). I am wondering is it best upon coming into the system to session the user's role with something like a: List<Role> roles; Where the Role class would have some sort of List<Module> modules; (can contain Company, Contact, etc.).? Something to the effect of: class Role{ string name; string desc; List<Module> modules; } And the module action class would have a set of actions (Create, Edit, Delete, etc.) for each module: class ModuleActions{ List<Action> actions; } And the action has a value of whether the user can perform the right: class Action{ string right; } Just a rough idea, I know the action could be an enum and the ModuleAction can probably be eliminated with a List<x, y>. My main question is what would be the best way to store this information in this type of application: Should I store it in the User Session state (I have a session class where I manage things related to the user). I generally load this during the initial loading of the application (global.asax). I can simply tack onto this session. Or should this be loaded at the page load event of each module (page load of company etc..). I eventually need to be able to hide / unhide various buttons / divs based on the user's role and that is what got me thinking to load this via session. Any examples or points would be great.

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  • What is the best currency API out there?

    - by YouBook
    I may be asking an odd question, but webmasters seem like a decent place to post this. I'm in the search for an accurate, easy API (such as using JSON or XML) so I can use my web application. I've been trying Google's secret API, but it's dependency isn't that good because of parsing the string (weird JSON format that PHP sometimes return incorrect data or truncates the string due to parsing error, but Google's API is fair but can be improved. So, all I'm asking is your current best currency API out there, I want to have them to include documented API so I can use it with PHP. Cheers.

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  • ASP.NET Hosting :: ASP.NET File Upload Control

    - by mbridge
    The asp.net FileUpload control allows a user to browse and upload files to the web server. From developers perspective, it is as simple as dragging and dropping the FileUpload control to the aspx page. An extra control, like a Button control, or some other control is needed, to actually save the file. <asp:FileUploadID="FileUpload1"runat="server"/> <asp:ButtonID="B1"runat="server"Text="Save"OnClick="B1_Click"/> By default, the FileUpload control allows a maximum of 4MB file to be uploaded and the execution timeout is 110 seconds. These properties can be changed from within the web.config file’s httpRuntime section. The maxRequestLength property determines the maximum file size that can be uploaded. The executionTimeout property determines the maximum time for execution. <httpRuntimemaxRequestLength="8192"executionTimeout="220"/> From code behind, the mime type, size of the file, file name and the extension of the file can be obtained. The maximum file size that can be uploaded can be obtained and modified using the System.Web.Configuration.HttpRuntimeSection class. Files can be alternatively saved using the System.IO.HttpFileCollection class. This collection class can be populated using the Request.Files property. The collection contains HttpPostedFile class which contains a reference to the class. using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using System.IO; using System.Configuration; using System.Web.Configuration;   namespace WebApplication1 {     public partial class WebControls : System.Web.UI.Page     {         protected void Page_Load(object sender, EventArgs e)         {         }           //Using FileUpload control to upload and save files         protected void B1_Click(object sender, EventArgs e)         {             if (FileUpload1.HasFile && FileUpload1.PostedFile.ContentLength > 0)             {                 //mime type of the uploaded file                 string mimeType = FileUpload1.PostedFile.ContentType;                   //size of the uploaded file                 int size = FileUpload1.PostedFile.ContentLength; // bytes                   //extension of the uploaded file                 string extension = System.IO.Path.GetExtension(FileUpload1.FileName);                                  //save file                 string path = Server.MapPath("path");                                 FileUpload1.SaveAs(path + FileUpload1.FileName);                              }             //maximum file size allowed             HttpRuntimeSection rt = new HttpRuntimeSection();             rt.MaxRequestLength = rt.MaxRequestLength * 2;             int length = rt.MaxRequestLength;                     //execution timeout             TimeSpan ts = rt.ExecutionTimeout;             double secomds = ts.TotalSeconds;           }           //Using Request.Files to save files         private void AltSaveFile()         {             HttpFileCollection coll = Request.Files;             for (int i = 0; i < coll.Count; i++)             {                 HttpPostedFile file = coll[i];                   if (file.ContentLength > 0)                     ;//do something             }         }     } }

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  • MythTV lost recordings - "No recordings available" and no recording rules either

    - by nimasmi
    I have a c.6 year old mythtv database. I recently upgraded from Ubuntu 10.04 to 12.04. This brought a MythTV upgrade from 0.24 to 0.25, which went well. Today, all my recordings have disappeared. They still exist in the /var/lib/mythtv/recordings folder, and the 'M' key in the Watch Recordings page says that there are 201 recordings available somewhere, but they will not display. See screenshot: (implicit thanks to whomever upvoted this, giving me sufficient reputation to upload images) Changing the filter does not remedy the fact that there is nothing shown in the lists. My Upcoming Recordings screen says that there are no rules set, but my list of previously recorded shows is still there, and has an entry from as recently as 3am today. mythbackend --printsched gives the following: user@box:~$ mythbackend --printsched 2012-09-22 12:59:20.537008 C mythbackend version: fixes/0.25 [v0.25.2-15-g46cab93] www.mythtv.org 2012-09-22 12:59:20.537043 C Qt version: compile: 4.8.1, runtime: 4.8.1 2012-09-22 12:59:20.537048 N Enabled verbose msgs: general 2012-09-22 12:59:20.537076 N Setting Log Level to LOG_INFO 2012-09-22 12:59:20.537142 I Added logging to the console 2012-09-22 12:59:20.537152 I Added database logging to table logging 2012-09-22 12:59:20.537279 N Setting up SIGHUP handler 2012-09-22 12:59:20.537373 N Using runtime prefix = /usr 2012-09-22 12:59:20.537394 N Using configuration directory = /home/user/.mythtv 2012-09-22 12:59:20.537999 I Assumed character encoding: en_GB.UTF-8 2012-09-22 12:59:20.538599 N Empty LocalHostName. 2012-09-22 12:59:20.538610 I Using localhost value of box 2012-09-22 12:59:20.538792 I Testing network connectivity to '192.168.1.2' 2012-09-22 12:59:20.539420 I Starting process manager 2012-09-22 12:59:20.541412 I Starting IO manager (read) 2012-09-22 12:59:20.541715 I Starting IO manager (write) 2012-09-22 12:59:20.541836 I Starting process signal handler 2012-09-22 12:59:20.684497 N Setting QT default locale to EN_GB 2012-09-22 12:59:20.684694 I Current locale EN_GB 2012-09-22 12:59:20.684813 N Reading locale defaults from /usr/share/mythtv//locales/en_gb.xml 2012-09-22 12:59:20.697623 I New static DB connectionDataDirectCon 2012-09-22 12:59:20.704769 I MythCoreContext: Connecting to backend server: 192.168.1.2:6543 (try 1 of 1) Calculating Schedule from database. Inputs, Card IDs, and Conflict info may be invalid if you have multiple tuners. 2012-09-22 12:59:27.710538 E MythSocket(21dfcd0:14): readStringList: Error, timed out after 7000 ms. 2012-09-22 12:59:27.710592 C Protocol version check failure. The response to MYTH_PROTO_VERSION was empty. This happens when the backend is too busy to respond, or has deadlocked in due to bugs or hardware failure. Things I have tried so far: restart the backend restart the frontend run mythtv-setup and check database passwords and IP addresses change the frontend setting for backend IP from localhost to 192.168.1.2 (the backend/frontend's IP) run optimize_mythdb.pl Other suggestions appreciated.

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  • Populate a WCF syndication podcast using MP3 ID3 metadata tags

    - by brian_ritchie
    In the last post, I showed how to create a podcast using WCF syndication.  A podcast is an RSS feed containing a list of audio files to which users can subscribe.  The podcast not only contains links to the audio files, but also metadata about each episode.  A cool approach to building the feed is reading this metadata from the ID3 tags on the MP3 files used for the podcast. One library to do this is TagLib-Sharp.  Here is some sample code: .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: Consolas, "Courier New", Courier, Monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } 1: var taggedFile = TagLib.File.Create(f); 2: var fileInfo = new FileInfo(f); 3: var item = new iTunesPodcastItem() 4: { 5: title = taggedFile.Tag.Title, 6: size = fileInfo.Length, 7: url = feed.baseUrl + fileInfo.Name, 8: duration = taggedFile.Properties.Duration, 9: mediaType = feed.mediaType, 10: summary = taggedFile.Tag.Comment, 11: subTitle = taggedFile.Tag.FirstAlbumArtist, 12: id = fileInfo.Name 13: }; 14: if (!string.IsNullOrEmpty(taggedFile.Tag.Album)) 15: item.publishedDate = DateTimeOffset.Parse(taggedFile.Tag.Album); This reads the ID3 tags into an object for later use in creating the syndication feed.  When the MP3 is created, these tags are set...or they can be set after the fact using the Properties dialog in Windows Explorer.  The only "hack" is that there isn't an easily accessible tag for "subtitle" or "published date" so I used other tags in this example. Feel free to change this to meet your purposes.  You could remove the subtitle & use the file modified data for example. That takes care of the episodes, for the feed level settings we'll load those from an XML file: .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: Consolas, "Courier New", Courier, Monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } 1: <?xml version="1.0" encoding="utf-8" ?> 2: <iTunesPodcastFeed 3: baseUrl ="" 4: title="" 5: subTitle="" 6: description="" 7: copyright="" 8: category="" 9: ownerName="" 10: ownerEmail="" 11: mediaType="audio/mp3" 12: mediaFiles="*.mp3" 13: imageUrl="" 14: link="" 15: /> Here is the full code put together. Read the feed XML file and deserialize it into an iTunesPodcastFeed classLoop over the files in a directory reading the ID3 tags from the audio files .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: Consolas, "Courier New", Courier, Monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } 1: public static iTunesPodcastFeed CreateFeedFromFiles(string podcastDirectory, string podcastFeedFile) 2: { 3: XmlSerializer serializer = new XmlSerializer(typeof(iTunesPodcastFeed)); 4: iTunesPodcastFeed feed; 5: using (var fs = File.OpenRead(Path.Combine(podcastDirectory, podcastFeedFile))) 6: { 7: feed = (iTunesPodcastFeed)serializer.Deserialize(fs); 8: } 9: foreach (var f in Directory.GetFiles(podcastDirectory, feed.mediaFiles)) 10: { 11: try 12: { 13: var taggedFile = TagLib.File.Create(f); 14: var fileInfo = new FileInfo(f); 15: var item = new iTunesPodcastItem() 16: { 17: title = taggedFile.Tag.Title, 18: size = fileInfo.Length, 19: url = feed.baseUrl + fileInfo.Name, 20: duration = taggedFile.Properties.Duration, 21: mediaType = feed.mediaType, 22: summary = taggedFile.Tag.Comment, 23: subTitle = taggedFile.Tag.FirstAlbumArtist, 24: id = fileInfo.Name 25: }; 26: if (!string.IsNullOrEmpty(taggedFile.Tag.Album)) 27: item.publishedDate = DateTimeOffset.Parse(taggedFile.Tag.Album); 28: feed.Items.Add(item); 29: } 30: catch 31: { 32: // ignore files that can't be accessed successfully 33: } 34: } 35: return feed; 36: } Usually putting a "try...catch" like this is bad, but in this case I'm just skipping over files that are locked while they are being uploaded to the web site.Here is the code from the last couple of posts.  

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  • How do you play or record audio (to .WAV) on Linux in C++? [closed]

    - by Jacky Alcine
    Hello, I've been looking for a way to play and record audio on a Linux (preferably Ubuntu) system. I'm currently working on a front-end to a voice recognition toolkit that'll automate a few steps required to adapt a voice model for PocketSphinx and Julius. Suggestions of alternative means of audio input/output are welcome, as well as a fix to the bug shown below. Here is the current code I've used so far to play a .WAV file: void Engine::sayText ( const string OutputText ) { string audioUri = "temp.wav"; string requestUri = this->getRequestUri( OPENMARY_PROCESS , OutputText.c_str( ) ); int error , audioStream; pa_simple *pulseConnection; pa_sample_spec simpleSpecs; simpleSpecs.format = PA_SAMPLE_S16LE; simpleSpecs.rate = 44100; simpleSpecs.channels = 2; eprintf( E_MESSAGE , "Generating audio for '%s' from '%s'..." , OutputText.c_str( ) , requestUri.c_str( ) ); FILE* audio = this->getHttpFile( requestUri , audioUri ); fclose(audio); eprintf( E_MESSAGE , "Generated audio."); if ( ( audioStream = open( audioUri.c_str( ) , O_RDONLY ) ) < 0 ) { fprintf( stderr , __FILE__": open() failed: %s\n" , strerror( errno ) ); goto finish; } if ( dup2( audioStream , STDIN_FILENO ) < 0 ) { fprintf( stderr , __FILE__": dup2() failed: %s\n" , strerror( errno ) ); goto finish; } close( audioStream ); pulseConnection = pa_simple_new( NULL , "AudioPush" , PA_STREAM_PLAYBACK , NULL , "openMary C++" , &simpleSpecs , NULL , NULL , &error ); for (int i = 0;;i++ ) { const int bufferSize = 1024; uint8_t audioBuffer[bufferSize]; ssize_t r; eprintf( E_MESSAGE , "Buffering %d..",i); /* Read some data ... */ if ( ( r = read( STDIN_FILENO , audioBuffer , sizeof (audioBuffer ) ) ) <= 0 ) { if ( r == 0 ) /* EOF */ break; eprintf( E_ERROR , __FILE__": read() failed: %s\n" , strerror( errno ) ); if ( pulseConnection ) pa_simple_free( pulseConnection ); } /* ... and play it */ if ( pa_simple_write( pulseConnection , audioBuffer , ( size_t ) r , &error ) < 0 ) { fprintf( stderr , __FILE__": pa_simple_write() failed: %s\n" , pa_strerror( error ) ); if ( pulseConnection ) pa_simple_free( pulseConnection ); } usleep(2); } /* Make sure that every single sample was played */ if ( pa_simple_drain( pulseConnection , &error ) < 0 ) { fprintf( stderr , __FILE__": pa_simple_drain() failed: %s\n" , pa_strerror( error ) ); if ( pulseConnection ) pa_simple_free( pulseConnection ); } } NOTE: If you want the rest of the code to this file, you can download it here directly from Launchpad.

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  • Internal Mutation of Persistent Data Structures

    - by Greg Ros
    To clarify, when I mean use the terms persistent and immutable on a data structure, I mean that: The state of the data structure remains unchanged for its lifetime. It always holds the same data, and the same operations always produce the same results. The data structure allows Add, Remove, and similar methods that return new objects of its kind, modified as instructed, that may or may not share some of the data of the original object. However, while a data structure may seem to the user as persistent, it may do other things under the hood. To be sure, all data structures are, internally, at least somewhere, based on mutable storage. If I were to base a persistent vector on an array, and copy it whenever Add is invoked, it would still be persistent, as long as I modify only locally created arrays. However, sometimes, you can greatly increase performance by mutating a data structure under the hood. In more, say, insidious, dangerous, and destructive ways. Ways that might leave the abstraction untouched, not letting the user know anything has changed about the data structure, but being critical in the implementation level. For example, let's say that we have a class called ArrayVector implemented using an array. Whenever you invoke Add, you get a ArrayVector build on top of a newly allocated array that has an additional item. A sequence of such updates will involve n array copies and allocations. Here is an illustration: However, let's say we implement a lazy mechanism that stores all sorts of updates -- such as Add, Set, and others in a queue. In this case, each update requires constant time (adding an item to a queue), and no array allocation is involved. When a user tries to get an item in the array, all the queued modifications are applied under the hood, requiring a single array allocation and copy (since we know exactly what data the final array will hold, and how big it will be). Future get operations will be performed on an empty cache, so they will take a single operation. But in order to implement this, we need to 'switch' or mutate the internal array to the new one, and empty the cache -- a very dangerous action. However, considering that in many circumstances (most updates are going to occur in sequence, after all), this can save a lot of time and memory, it might be worth it -- you will need to ensure exclusive access to the internal state, of course. This isn't a question about the efficacy of such a data structure. It's a more general question. Is it ever acceptable to mutate the internal state of a supposedly persistent or immutable object in destructive and dangerous ways? Does performance justify it? Would you still be able to call it immutable? Oh, and could you implement this sort of laziness without mutating the data structure in the specified fashion?

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  • set installer background / not able to run early_command in custom preseed file (precise)

    - by user73093
    I have a custom preseed file for a Precise Live CD (which is well loaded on boot, I checked syslog for that). My initial problem is that when booting in install mode (default behavior for a Live CD), ubiquity runs X with a default wallpaper which is hardcoded to /usr/share/backgrounds/warty-final-ubuntu.png in Ubiquity code. So my idea was to run early_command (https://help.ubuntu.com/12.04/installation-guide/i386/preseed-advanced.html) to copy my custom wallpaper over /usr/share/backgrounds/warty-final-ubuntu.png. Assuming my custom wallpaper allready resides on the rootfs in /usr/share/backgrounds. But... It seems the early_command never runs (and I'm sure the preseed file is taken into account) Here is what I have added to my preseed file: d-i preseed/early_command string cp /usr/share/backgrounds/mywallpaper-defaults.jpg /usr/share/backgrounds/warty-final-ubuntu.png Even this one is never run: d-i preseed/early_command string /usr/bin/touch /tmp/testearly Thanks for helping !!

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  • Wine 1.5 %ProgramFiles% error

    - by elclanrs
    I'm trying to install d3dx9 with winetricks on wine 1.5 from ppa and I keep getting an error. I tried: WINEARCH=win32 WINEPREFIX=~/.win32 winecfg sudo WINEARCH=win32 WINEPREFIX=~/.win32 winetricks And still get this error: wine cmd.exe /c echo '%ProgramFiles%' returned empty string If I type wine cmd.exe /c echo '%ProgramFiles%' into the terminal I get C:\Program Files so the path seems correct but not when I run winetricks. I also tried this regedit fix with no luck. Any ideas?

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  • JavaScript function to Redirects parent of IFrame to specified URL

    - by Michael Freidgeim
    /// <summary>    /// Redirects parent of IFrame to specified URL    /// If current page doesn't have parent, redirect itself    /// </summary>    /// <param name="page"></param>    /// <param name="url"></param>    public static void NavigateParentToUrl(Page page, string url)    {     String script = @" try { var sUrl='" + url + @"'; if (self.parent.frames.length != 0)     self.parent.location=sUrl; else   self.location = sUrl; } catch (Exception) {} ";     page.ClientScript.RegisterStartupScript(TypeForClientScript(), MethodBase.GetCurrentMethod().Name, script, true);    }    /// <summary>

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  • Java - 2d Array Tile Map Collision

    - by Corey
    How would I go about making certain tiles in my array collide with my player? Like say I want every number 2 in the array to collide. I am reading my array from a txt file if that matters and I am using the slick2d library. Here is my code if needed. public class Tiles { Image[] tiles = new Image[3]; int[][] map = new int[500][500]; Image grass, dirt, mound; SpriteSheet tileSheet; int tileWidth = 32; int tileHeight = 32; public void init() throws IOException, SlickException { tileSheet = new SpriteSheet("assets/tiles.png", tileWidth, tileHeight); grass = tileSheet.getSprite(0, 0); dirt = tileSheet.getSprite(7, 7); mound = tileSheet.getSprite(2, 6); tiles[0] = grass; tiles[1] = dirt; tiles[2] = mound; int x=0, y=0; BufferedReader in = new BufferedReader(new FileReader("assets/map.txt")); String line; while ((line = in.readLine()) != null) { String[] values = line.split(","); for (String str : values) { int str_int = Integer.parseInt(str); map[x][y]=str_int; //System.out.print(map[x][y] + " "); y=y+1; } //System.out.println(""); x=x+1; y = 0; } in.close(); } public void update() { } public void render(GameContainer gc) { for(int x = 0; x < 50; x++) { for(int y = 0; y < 50; y ++) { int textureIndex = map[y][x]; Image texture = tiles[textureIndex]; texture.draw(x*tileWidth,y*tileHeight); } } } } I tried something like this, but I it doesn't ever "collide". X and y are my player position. if (tiles.map[(int)x/32][(int)y/32] == 2) { System.out.println("Collided"); }

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  • Strengthening code with possibly useless exception handling

    - by rdurand
    Is it a good practice to implement useless exception handling, just in case another part of the code is not coded correctly? Basic example A simple one, so I don't loose everybody :). Let's say I'm writing an app that will display a person's information (name, address, etc.), the data being extracted from a database. Let's say I'm the one coding the UI part, and someone else is writing the DB query code. Now imagine that the specifications of your app say that if the person's information is incomplete (let's say, the name is missing in the database), the person coding the query should handle this by returning "NA" for the missing field. What if the query is poorly coded and doesn't handle this case? What if the guy who wrote the query handles you an incomplete result, and when you try to display the informations, everything crashes, because your code isn't prepared to display empty stuff? This example is very basic. I believe most of you will say "it's not your problem, you're not responsible for this crash". But, it's still your part of the code which is crashing. Another example Let's say now I'm the one writing the query. The specifications don't say the same as above, but that the guy writing the "insert" query should make sure all the fields are complete when adding a person to the database to avoid inserting incomplete information. Should I protect my "select" query to make sure I give the UI guy complete informations? The questions What if the specifications don't explicitly say "this guy is the one in charge of handling this situation"? What if a third person implements another query (similar to the first one, but on another DB) and uses your UI code to display it, but doesn't handle this case in his code? Should I do what's necessary to prevent a possible crash, even if I'm not the one supposed to handle the bad case? I'm not looking for an answer like "(s)he's the one responsible for the crash", as I'm not solving a conflict here, I'd like to know, should I protect my code against situations it's not my responsibility to handle? Here, a simple "if empty do something" would suffice. In general, this question tackles redundant exception handling. I'm asking it because when I work alone on a project, I may code 2-3 times a similar exception handling in successive functions, "just in case" I did something wrong and let a bad case come through.

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  • Is case after case in a switch efficient?

    - by RandomGuy
    Just a random question regarding switch case efficiency in case after case; is the following code (assume pseudo code): function bool isValid(String myString){ switch(myString){ case "stringA": case "stringB": case "stringC": return true; default: return false; } more efficient than this: function bool isValid(String myString){ switch(myString){ case "stringA": return true; case "stringB": return true; case "stringC": return true; default: return false; } Or is the performance equal? I'm not thinking in a specific language but if needed let's assume it's Java or C (for this case would be needed to use chars instead of strings).

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  • Tuxedo Load Balancing

    - by Todd Little
    A question I often receive is how does Tuxedo perform load balancing.  This is often asked by customers that see an imbalance in the number of requests handled by servers offering a specific service. First of all let me say that Tuxedo really does load or request optimization instead of load balancing.  What I mean by that is that Tuxedo doesn't attempt to ensure that all servers offering a specific service get the same number of requests, but instead attempts to ensure that requests are processed in the least amount of time.   Simple round robin "load balancing" can be employed to ensure that all servers for a particular service are given the same number of requests.  But the question I ask is, "to what benefit"?  Instead Tuxedo scans the queues (which may or may not correspond to servers based upon SSSQ - Single Server Single Queue or MSSQ - Multiple Server Single Queue) to determine on which queue a request should be placed.  The scan is always performed in the same order and during the scan if a queue is empty the request is immediately placed on that queue and request routing is done.  However, should all the queues be busy, meaning that requests are currently being processed, Tuxedo chooses the queue with the least amount of "work" queued to it where work is the sum of all the requests queued weighted by their "load" value as defined in the UBBCONFIG file.  What this means is that under light loads, only the first few queues (servers) process all the requests as an empty queue is often found before reaching the end of the scan.  Thus the first few servers in the queue handle most of the requests.  While this sounds non-optimal, in fact it capitalizes on the underlying operating systems and hardware behavior to produce the best possible performance.  Round Robin scheduling would spread the requests across all the available servers and thus require all of them to be in memory, and likely not share much in the way of hardware or memory caches.  Tuxedo's system maximizes the various caches and thus optimizes overall performance.  Hopefully this makes sense and now explains why you may see a few servers handling most of the requests.  Under heavy load, meaning enough load to keep all servers that can handle a request busy, you should see a relatively equal number of requests processed.  Next post I'll try and cover how this applies to servers in a clustered (MP) environment because the load balancing there is a little more complicated. Regards,Todd LittleOracle Tuxedo Chief Architect

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  • Best exception handling practices or recommendations?

    - by user828584
    I think the two main problems with my programs are my code structure/organization and my error handling. I'm reading Code Complete 2, but I need something to read for working with potential problems. For example, on a website, if something can only happen if the user tampers with data via javascript, do you write for that? Also, when do you not catch errors? When you write a class that expects a string and an int as input, and they aren't a string and int, do you check for that, or do you let it bubble up to the calling method that passed incorrect parameters? I know this is a broad topic that can't be answered in a single answer here, so what I'm looking for is a book or resource that's commonly accepted as teaching proper exception handling practice.

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  • Finding the lowest average Hamming distance when the order of the strings matter

    - by user1049697
    I have a sequence of binary strings that I want to find a match for among a set of longer sequences of binary strings. A match means that the compared sequence gives the lowest average Hamming distance when all elements in the shorter sequence have been matched against a sequence in one of the longer sets. Let me try to explain with an example. I have a set of video frames that have been hashed using a perceptual hashing algorithm so that the video frames that look the same has roughly the same hash. I want to match a short video clip against a set of longer videos, to see if the clip is contained in one of these. This means that I need to find out where the sequence of the hashed frames in the short video has the lowest average Hamming distance when compared with the long videos. The short video is the sub strings Sub1, Sub2 and Sub3, and I want to match them against the hashes of the long videos in Src. The clue here is that the strings need to match in the specific order that they are given in, e.g. that Sub1 always has to match the element before Sub2, and Sub2 always has to match the element before Sub3. In this example it would map thusly: Sub1-Src3, Sub2-Src4 and Sub3-Src5. So the question is this: is there an algorithm for finding the lowest average Hamming distance when the order of the elements compared matter? The naïve approach to compare the substring sequence to every source string won't cut it of course, so I need something that preferably can match a (much) shorter sub string to a set of million of elements. I have looked at MVP-trees, BK-trees and similar, but everything seems to only take into account one binary string and not a sequence of them. Sub1: 100111011111011101 Sub2: 110111000010010100 Sub3: 111111010110101101 Src1: 001011010001010110 Src2: 010111101000111001 Src3: 101111001110011101 Src4: 010111100011010101 Src5: 001111010110111101 Src6: 101011111111010101 I have added a calculation of the examples below. (The Hamming distances aren't correct, but it doesn't matter) **Run 1.** dist(Sub1, Src1) = 8 dist(Sub2, Src2) = 10 dist(Sub3, Src3) = 12 average = 10 **Run 2.** dist(Sub1, Src2) = 10 dist(Sub2, Src3) = 12 dist(Sub3, Src4) = 10 average = 11 **Run 3.** dist(Sub1, Src3) = 7 dist(Sub2, Src4) = 6 dist(Sub3, Src5) = 10 average = 8 **Run 4.** dist(Sub1, Src3) = 10 dist(Sub2, Src4) = 4 dist(Sub3, Src5) = 2 average = 5 So the winner here is sequence 4 with an average distance of 5.

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  • How to unicode Myanmar texts on Java? [closed]

    - by Spacez Ly Wang
    I'm just beginner of Java. I'm trying to unicode (display) correctly Myanmar texts on Java GUI ( Swing/Awt ). I have four TrueType fonts which support Myanmar unicode texts. There are Myanmar3, Padauk, Tharlon, Myanmar Text ( Window 8 built-in ). You may need the fonts before the code. Google the fonts, please. Each of the fonts display on Java GUI differently and incorrectly. Here is the code for GUI Label displaying myanmar texts: ++++++++++++++++++++++++ package javaapplication1; import javax.swing.JFrame; import javax.swing.JTextField; public class CusFrom { private static void createAndShowGUI() { JFrame frame = new JFrame("Hello World Swing"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); String s = "\u1015\u102F \u103C\u1015\u102F"; JLabel label = new JLabel(s); label.setFont(new java.awt.Font("Myanmar3", 0, 20));// font insert here, Myanmar Text, Padauk, Myanmar3, Tharlon frame.getContentPane().add(label); frame.pack(); frame.setVisible(true); } public static void main(String[] args) { javax.swing.SwingUtilities.invokeLater(new Runnable() { public void run() { createAndShowGUI(); } }); } } ++++++++++++++++++++++++ Outputs vary. See the pictures: Myanmar3 IMG Padauk IMG Tharlon IMG Myanmar Text IMG What is the correct form? (on notepad) Well, next is the code for GUI Textfield inputting Myanmar texts: ++++++++++++++++++++++++ package javaapplication1; import javax.swing.JFrame; import javax.swing.JTextField; public class XusForm { private static void createAndShowGUI() { JFrame frame = new JFrame("Frame Title"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JTextField textfield = new JTextField(); textfield.setFont(new java.awt.Font("Myanmar3", 0, 20)); frame.getContentPane().add(textfield); frame.pack(); frame.setVisible(true); } public static void main(String[] args) { javax.swing.SwingUtilities.invokeLater(new Runnable() { public void run() { createAndShowGUI(); } }); } } ++++++++++++++++++++++++ Outputs vary when I input keys( unicode text ) on keyboards. Myanmar Text Output IMG Padauk Output IMG Myanmar3 Output IMG Tharlon Output IMG Those fonts work well on Linux when opening text files with Text Editor application. My Question is how to unicode Myanmar texts on Java GUI. Do I need additional codes left to display well? Or Does Java still have errors? The fonts display well on Web Application (HTML, CSS) but I'm not sure about displaying on Java Web Application.

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  • Unity: Assigning a key to perform an action in the inspector

    - by Marc Pilgaard
    I am trying to write a simple piece of code in JavaScript where a button toggles the activation of a shield, by dragging a prefab with Resources.load("ActivateShieldPreFab") and destroying it again (Haven't implemented that yet). I wish to assign this button through the inspector, so I have created a string variable which appears as intended in the inspector. Though it doesn't seem to register the inspector input, even though I changed the value through the inspector. It only provides the error: "Input Key named: is unknown" When the button name is assigned within the code, there is no issues. Code as follows: var ShieldOn = false; var stringbutton : String; function Start(){ } function Update () { if(Input.GetKey(stringbutton) && ShieldOn != true) { Instantiate(Resources.load("ActivateShieldPreFab"), Vector3 (0, 0, 0), Quaternion.identity); ShieldOn = true; } }

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  • Brightness Crash and Fan issues in 12.04.1

    - by S.A. McIntosh
    I would just like to state beforehand that I am a total novice in using Ubuntu when it comes to the more complex issues. So I thought it would be best to finally come here and ask for help before being re-directed or closed out for a solution. I have already looked high and low on this board for one but nothing came up for my particular case, so I might as well take a shot asking for the first time here. This is what I have at the moment: -Dell Insprion 1764 w/ 64-bit Intel i5 Core -Dual Boot: Windows 7/Ubuntu 12.04.1 32-bit (from 12.04 install) -Unity shell -Linux kernel: 3.2.0-32 generic-pae ...and this is my fglrxinfo: OpenGL vendor string: Advanced Micro Devices, Inc. OpenGL renderer string: ATI Mobility Radeon HD 5000 Series OpenGL version string: 4.2.11627 Compatibility Profile Context The one issue I have with using Ubuntu is brightness. With the driver in every time I use the slider in the brightness and lock settings or use the keyboard function, it freezes, goes black and comes up with a scrambled colors page like this in the video. So I have looked all over this board and the web for answers looking for a solution that might have an answer. This is what I have done so far to fix this: -First Solution: Looking around, I found this small fix using terminal: sudo gedit /etc/rc.local followed by adding this into "rc.local" echo # > /sys/class/backlight/acpi_video0/brightness This works rarely with the graphics driver still in and I often get lucky say during restart but reboot would only snap back the brightness at max. -Second Solution Simply remove the graphics driver while leaving the solution of first behind. This solves the issue but results in having the monitor flicker and flash at startup which in itself is not a problem to me but maybe not so good for monitor health. Also it causes the fan to speed up throughout the session and render any program that needs the driver useless. -Third Solution This is the most obvious. Just simply use the brightness on AMD Catalyst Control Center software that came with the driver, and I can say that it's form of brightness is HORRIBLE compared to the actual settings. Which leads up to where I am now, back to the driver to stop the fan speed-up and seems that the only solution to the brightness crash is to use the keyboard-controlled brightness at the login screen NOT the desktop if I want the issued effect but will just snap at max bright again if I restart. Fan speed problem is dealt with but now run the risk of crashing my computer if I so much touch the brightness settings. Speaking of which I found this on launchpad and it seems that the issue has been going far since June of 2012. Any help, redirect link or reference would be greatly appreciated. Thank you.

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  • Is ASP.NET MVC completely (and exclusively) based on conventions?

    - by Mike Valeriano
    --TL;DR Is there a "Hello World!" ASP.NET MVC tutorial out there that doesn't rely on conventions and "stock" projects? Is it even possible to take advantage of the technology without reusing the default file structure, and start from a single "hello_world.asp" file or something (like in PHP)? Am I completely mistaken and I should be looking somewhere else, maybe this? I'm interested in the MVC framework, not Web Forms --Background I've played a bit with PHP in the past, just for fun, and now I'm back to it since web development became relevant for me once again. I'm no professional, but I try to gain as much knowledge and control over the technology I'm working with as possible. I'm using Visual Studio 2012 for C# - my "desktop" language of choice - and since I got the Professional Edition from Dreamspark, the Web Development Tools are available, including ASP.NET MVC 4. I won't touch Web Forms, but the MVC Framework got my attention because the MVC pattern is something I can really relate to, since it provides the control I want but... not quite. Learning PHP was easy - and right form the start I could just create a "hello_world.php" file and just do something like this for immediate results: <!-- file: hello_world.php --> <?php> echo "Hello World!"; <?> But I couldn't find a single ASP.NET (MVC) tutorial out there (I'll be sure to buy one of the upcoming MVC 4 books, only a month away or so) that would start like that. They all start with a sample project, building up knowledge from the basics and heavily using conventions as they go along. Which is fine, I suppose, but it's now the best way for me to learn things. Even the "Empty" project template for a new ASP.NET MVC 4 Application in VS2012 is not empty at all: several files and folders are created for you - much like a new C# desktop application project, but with C# I can in fact start from scratch, creating the project structure myself. It is not the case with PHP: I can choose from a plethora of different MVC frameworks I can just create my own framework I can just skip frameworks altogether, and toss random PHP along with my HTML on a single file and make it work I understand the framework needs to establish some rules, but what if I just want to create a single page website with some C# logic behind it? Do I really need to create a whole bloat of files and folders for the sake of convention? Also, please understand that I haven't gotten far on any of those tutorials mainly because of this reason, but, if that's the only way to do it, I'll go for it using one of the books I've mentioned before. This is my first contact with ASP.NET but from the few comparisons I've read, I believe I should stay the hell away from Web Forms. Thank you. (Please forgive the broken English - it is not my primary language.)

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  • How to customize the ubuntu gnome 3 desktop?

    - by Francesco
    This is maybe a stupid question, but how can I choose my own background image on ubuntu gnome 3?? I click on Settings - Background - then I click on the current background preview to change it but I see only the defaults images! No + symbol to add or something. On the 'Pictures' tab there is nothing to select, I get an empty white page? I am running ubuntu gnome 13.04 3.9.6-030906-generic. Thanks!

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  • How should I make searching a relational database more efficient?

    - by Travis J
    This is in the scope of a web application. I have a database which has a few nested relations. There is a feature which depicts the history of a large chain of relations. It is essentially a data analysis feature. The issue is that in order to search, a large object graph must be loaded - the loading time for this object graph is not quick enough to be viable. The problem is that without loading the whole graph it makes searching from a single string nearly impossible. In order to search, explicit fields must be specified and the search data supplied. Is there a design pattern for exposing the data in a way which facilitates a single string search instead of having to explicitly define parameters?

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  • Organizing Git repositories with common nested sub-modules

    - by André Caron
    I'm a big fan of Git sub-modules. I like to be able to track a dependency along with its version, so that you can roll-back to a previous version of your project and have the corresponding version of the dependency to build safely and cleanly. Moreover, it's easier to release our libraries as open source projects as the history for libraries is separate from that of the applications that depend on them (and which are not going to be open sourced). I'm setting up workflow for multiple projects at work, and I was wondering how it would be if we took this approach a bit of an extreme instead of having a single monolithic project. I quickly realized there is a potential can of worms in really using sub-modules. Supposing a pair of applications: studio and player, and dependent libraries core, graph and network, where dependencies are as follows: core is standalone graph depends on core (sub-module at ./libs/core) network depdends on core (sub-module at ./libs/core) studio depends on graph and network (sub-modules at ./libs/graph and ./libs/network) player depends on graph and network (sub-modules at ./libs/graph and ./libs/network) Suppose that we're using CMake and that each of these projects has unit tests and all the works. Each project (including studio and player) must be able to be compiled standalone to perform code metrics, unit testing, etc. The thing is, a recursive git submodule fetch, then you get the following directory structure: studio/ studio/libs/ (sub-module depth: 1) studio/libs/graph/ studio/libs/graph/libs/ (sub-module depth: 2) studio/libs/graph/libs/core/ studio/libs/network/ studio/libs/network/libs/ (sub-module depth: 2) studio/libs/network/libs/core/ Notice that core is cloned twice in the studio project. Aside from this wasting disk space, I have a build system problem because I'm building core twice and I potentially get two different versions of core. Question How do I organize sub-modules so that I get the versioned dependency and standalone build without getting multiple copies of common nested sub-modules? Possible solution If the the library dependency is somewhat of a suggestion (i.e. in a "known to work with version X" or "only version X is officially supported" fashion) and potential dependent applications or libraries are responsible for building with whatever version they like, then I could imagine the following scenario: Have the build system for graph and network tell them where to find core (e.g. via a compiler include path). Define two build targets, "standalone" and "dependency", where "standalone" is based on "dependency" and adds the include path to point to the local core sub-module. Introduce an extra dependency: studio on core. Then, studio builds core, sets the include path to its own copy of the core sub-module, then builds graph and network in "dependency" mode. The resulting folder structure looks like: studio/ studio/libs/ (sub-module depth: 1) studio/libs/core/ studio/libs/graph/ studio/libs/graph/libs/ (empty folder, sub-modules not fetched) studio/libs/network/ studio/libs/network/libs/ (empty folder, sub-modules not fetched) However, this requires some build system magic (I'm pretty confident this can be done with CMake) and a bit of manual work on the part of version updates (updating graph might also require updating core and network to get a compatible version of core in all projects). Any thoughts on this?

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