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  • Raid 1 array won't assemble after power outage. How do I fix this ext4 mirror?

    - by Forkrul Assail
    Two ext4 drives on Raid 1 with mdadm won't reassemble after the power went out for an extended period (UPS drained). After turning the machine back on, mdadm said that the array was degraded, after which it took about 2 days for a full resync, which completed without problems. On trying to remount the array I get: mount: you must specify the filesystem type cat /etc/fstab lines relevant to setup: /dev/md127 /media/mediapool ext4 defaults 0 0 dmesg | tail (on trying to mount) says: [ 1050.818782] EXT3-fs (md127): error: can't find ext3 filesystem on dev md127. [ 1050.849214] EXT4-fs (md127): VFS: Can't find ext4 filesystem [ 1050.944781] FAT-fs (md127): invalid media value (0x00) [ 1050.944782] FAT-fs (md127): Can't find a valid FAT filesystem [ 1058.272787] EXT2-fs (md127): error: can't find an ext2 filesystem on dev md127. cat /proc/mdstat says: Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10] md127 : active (auto-read-only) raid1 sdj[2] sdi[0] 2930135360 blocks super 1.2 [2/2] [UU] unused devices: <none> fsck /dev/md127 says: fsck from util-linux 2.20.1 e2fsck 1.42 (29-Nov-2011) fsck.ext2: Superblock invalid, trying backup blocks... fsck.ext2: Bad magic number in super-block while trying to open /dev/md127 The superblock could not be read or does not describe a correct ext2 filesystem. If the device is valid and it really contains an ext2 filesystem (and not swap or ufs or something else), then the superblock is corrupt, and you might try running e2fsck with an alternate superblock: e2fsck -b 8193 <device> mdadm -E /dev/sdi gives me: /dev/sdi: Magic : a92b4efc Version : 1.2 Feature Map : 0x0 Array UUID : 37ac1824:eb8a21f6:bd5afd6d:96da6394 Name : sojourn:33 Creation Time : Sat Nov 10 10:43:52 2012 Raid Level : raid1 Raid Devices : 2 Avail Dev Size : 5860271016 (2794.40 GiB 3000.46 GB) Array Size : 2930135360 (2794.39 GiB 3000.46 GB) Used Dev Size : 5860270720 (2794.39 GiB 3000.46 GB) Data Offset : 262144 sectors Super Offset : 8 sectors State : clean Device UUID : 3e6e9a4f:6c07ab3d:22d47fce:13cecfd0 Update Time : Tue Nov 13 20:34:18 2012 Checksum : f7d10db9 - correct Events : 27 Device Role : Active device 0 Array State : AA ('A' == active, '.' == missing) boot@boot ~ $ sudo mdadm -E /dev/sdj /dev/sdj: Magic : a92b4efc Version : 1.2 Feature Map : 0x0 Array UUID : 37ac1824:eb8a21f6:bd5afd6d:96da6394 Name : sojourn:33 Creation Time : Sat Nov 10 10:43:52 2012 Raid Level : raid1 Raid Devices : 2 Avail Dev Size : 5860271016 (2794.40 GiB 3000.46 GB) Array Size : 2930135360 (2794.39 GiB 3000.46 GB) Used Dev Size : 5860270720 (2794.39 GiB 3000.46 GB) Data Offset : 262144 sectors Super Offset : 8 sectors State : clean Device UUID : 7fb84af4:e9295f7b:ede61f27:bec0cb57 Update Time : Tue Nov 13 20:34:18 2012 Checksum : b9d17fef - correct Events : 27 Device Role : Active device 1 Array State : AA ('A' == active, '.' == missing) machine@user ~ dmesg | tail [ 61.785866] init: alsa-restore main process (2736) terminated with status 99 [ 68.433548] eth0: no IPv6 routers present [ 534.142511] EXT4-fs (sdi): ext4_check_descriptors: Block bitmap for group 0 not in group (block 2838187772)! [ 534.142518] EXT4-fs (sdi): group descriptors corrupted! [ 546.418780] EXT2-fs (sdi): error: couldn't mount because of unsupported optional features (240) [ 549.654127] EXT3-fs (sdi): error: couldn't mount because of unsupported optional features (240) Since this is Raid 1 it was suggested that I try and mount or fsck the drives separately. After a long fsck on one drive, it ended with this as tail: Illegal double indirect block (2298566437) in inode 39717736. CLEARED. Illegal block #4231180 (2611866932) in inode 39717736. CLEARED. Error storing directory block information (inode=39717736, block=0, num=1092368): Memory allocation failed Recreate journal? yes Creating journal (32768 blocks): Done. *** journal has been re-created - filesystem is now ext3 again *** The drive however still doesn't want to mount: dmesg | tail [ 170.674659] md: export_rdev(sdc) [ 170.675152] md: export_rdev(sdc) [ 195.275288] md: export_rdev(sdc) [ 195.275876] md: export_rdev(sdc) [ 1338.540092] CE: hpet increased min_delta_ns to 30169 nsec [26125.734105] EXT4-fs (sdc): ext4_check_descriptors: Checksum for group 0 failed (43502!=37987) [26125.734115] EXT4-fs (sdc): group descriptors corrupted! [26182.325371] EXT3-fs (sdc): error: couldn't mount because of unsupported optional features (240) [27083.316519] EXT4-fs (sdc): ext4_check_descriptors: Checksum for group 0 failed (43502!=37987) [27083.316530] EXT4-fs (sdc): group descriptors corrupted! Please help me fix this. I never in my wildest nightmares thought a complete mirror would die this badly. Am I missing something? Suggestions on fixing this? Could someone explain why it would resync after the powerout, only to seemingly nuke the drive? Thanks for reading. Any help much appreciated. I've tried everything I can think of, including booting and filesystem checking with SystemRescue and Ubuntu liveboot discs.

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  • PHP - How to modify multi-dimensional array item from within a function?

    - by Marc
    My problem is as follows. I have a multidimensional array. I declare my array. Then, I run some code that populates my array partially. Then i run a function, which among others is supposed to modify some item in my array from within the function. This is unfortunately not working. So my question is simple. Is it normal? And if yes, how can I overcome this. Thank you very much in advance for your replies. Cheers. Marc. $list = array([0]=> array( [name]=>'James' [group]=>'' ) ); my_function(); print_r($list); function my_function(){ //some code here $list[0]['group'] = 'groupA'; }

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  • If array is thread safe, what the issue with this function?

    - by Ajay Sharma
    I am totally lost with the things that is happening with my code.It make me to think & get clear with Array's thread Safe concept. Is NSMutableArray OR NSMutableDictionary Thread Safe ? While my code is under execution, the values for the MainArray get's changes although, that has been added to Array. Please try to execute this code, onyour system its very much easy.I am not able to get out of this Trap. It is the function where it is returning Array. What I am Looking to do is : -(Array) (Main Array) --(Dictionary) with Key Value (Multiple Dictionary in Main Array) ----- Above dictionary has 9 Arrays in it. This is the structure I am developing for Array.But even before #define TILE_ROWS 3 #define TILE_COLUMNS 3 #define TILE_COUNT (TILE_ROWS * TILE_COLUMNS) -(NSArray *)FillDataInArray:(int)counter { NSMutableArray *temprecord = [[NSMutableArray alloc] init]; for(int i = 0; i <counter;i++) { if([temprecord count]<=TILE_COUNT) { NSMutableDictionary *d1 = [[NSMutableDictionary alloc]init]; [d1 setValue:[NSString stringWithFormat:@"%d/2011",i+1] forKey:@"serial_data"]; [d1 setValue:@"Friday 13 Sep 12:00 AM" forKey:@"date_data"]; [d1 setValue:@"Description Details " forKey:@"details_data"]; [d1 setValue:@"Subject Line" forKey:@"subject_data"]; [temprecord addObject:d1]; d1= nil; [d1 release]; if([temprecord count]==TILE_COUNT) { NSMutableDictionary *holderKey = [[NSMutableDictionary alloc]initWithObjectsAndKeys:temprecord,[NSString stringWithFormat:@"%d",[casesListArray count]+1],nil]; [self.casesListArray addObject:holderKey]; [holderKey release]; holderKey =nil; [temprecord removeAllObjects]; } } else { [temprecord removeAllObjects]; NSMutableDictionary *d1 = [[NSMutableDictionary alloc]init]; [d1 setValue:[NSString stringWithFormat:@"%d/2011",i+1] forKey:@"serial_data"]; [d1 setValue:@"Friday 13 Sep 12:00 AM" forKey:@"date_data"]; [d1 setValue:@"Description Details " forKey:@"details_data"]; [d1 setValue:@"Subject Line" forKey:@"subject_data"]; [temprecord addObject:d1]; d1= nil; [d1 release]; } } return temprecord; [temprecord release]; } What is the problem with this Code ? Every time there are 9 records in Array, it just replaces the whole Array value instead of just for specific key Value.

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  • Dashcode Web App: How to programmatically manipulate bound array in dataSource?

    - by Kross
    Hi Everyone, I've started using Dashcode to write an interface for presenting the report data for some of our Cocoa tools. I am using a Dashcode data source and bindings to populate the elements in the WebView, and it all seems to be working well so far. One of the objects in my dataSource is an array of objects that I would like to manipulate programmatically. I can change the object values in the array just fine but if I want to replace the array, or any objects in the array, my bound table isn't able to observe the added objects. Here is the code that I thought would let me easily replace the bound array with new content: var dataSource = dashcode.getDataSource("reportData"); var newDetailArray = testArray(); dataSource.setValueForKeyPath(newDetailArray, "content.detailArray"); But this throws the exception: Exception while binding "content" to keypath "arrangedObjects " TypeError: Result of expression 'this.object.valueForKeyPath' [undefined] is not a function. Is there something I'm missing that will let me easily manipulate the array's contents programmatically?

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  • jQuery, array form radio button name problem.

    - by borayeris
    <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>click div to select hidden options</title> <script type="text/javascript" src="jquery-1.4.4.js"></script> <style type="text/css"> .clickDiv { width:50px; height:50px; cursor:crosshair; } .red {border:1px #000 solid;} .green {border:1px #000 solid;} .redBG {background:#F00;} .greenBG {background:#0F0;} </style> <script type="text/javascript"> $(function() { $('div.clickDiv.red').click(function(){ var secilenMadde=$(this).attr('madde'); $('div#write').text(secilenMadde); $('input[name='+secilenMadde+'][value=red]').attr('checked', 'checked'); $('div.clickDiv.red[madde='+secilenMadde+']').addClass('redBG'); $('div.clickDiv.green[madde='+secilenMadde+']').removeClass('greenBG'); }); $('div.clickDiv.green').click(function(){ var secilenMadde=$(this).attr('madde'); $('div#write').text(secilenMadde); $('input[name='+secilenMadde+'][value=green]').attr('checked', 'checked'); $('div.clickDiv.green[madde='+secilenMadde+']').addClass('greenBG'); $('div.clickDiv.red[madde='+secilenMadde+']').removeClass('redBG'); }); }); </script> </head> <body> <div id="write"></div> <form id="formId" name="formName" method="post"> <table> <tr> <td><div class="clickDiv red" madde="line1"></div></td> <td><div class="clickDiv green" madde="line1"></div></td> </tr> <tr> <td><div class="clickDiv red" madde="line2"></div></td> <td><div class="clickDiv green" madde="line2"></div></td> </tr> </table> <label for="line1red"><input id="line1red" type="radio" name="line1" value="red" /> Red</label> <label for="line1green"><input id="line1green" type="radio" name="line1" value="green" /> Green</label><br /> <label for="line2red"><input type="radio" name="line2" value="red" /> Red</label> <label for="line2green"><input type="radio" name="line2" value="green" /> Green</label> </form> </body> </html> This works. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>click div to select hidden options</title> <script type="text/javascript" src="jquery-1.4.4.js"></script> <style type="text/css"> .clickDiv { width:50px; height:50px; cursor:crosshair; } .red {border:1px #000 solid;} .green {border:1px #000 solid;} .redBG {background:#F00;} .greenBG {background:#0F0;} </style> <script type="text/javascript"> $(function() { $('div.clickDiv.red').click(function(){ var secilenMadde=$(this).attr('madde'); $('div#write').text(secilenMadde); $('input[name='+secilenMadde+'][value=red]').attr('checked', 'checked'); $('div.clickDiv.red[madde='+secilenMadde+']').addClass('redBG'); $('div.clickDiv.green[madde='+secilenMadde+']').removeClass('greenBG'); }); $('div.clickDiv.green').click(function(){ var secilenMadde=$(this).attr('madde'); $('div#write').text(secilenMadde); $('input[name='+secilenMadde+'][value=green]').attr('checked', 'checked'); $('div.clickDiv.green[madde='+secilenMadde+']').addClass('greenBG'); $('div.clickDiv.red[madde='+secilenMadde+']').removeClass('redBG'); }); }); </script> </head> <body> <div id="write"></div> <form id="formId" name="formName" method="post"> <table> <tr> <td><div class="clickDiv red" madde="line[1]"></div></td> <td><div class="clickDiv green" madde="line[1]"></div></td> </tr> <tr> <td><div class="clickDiv red" madde="line[2]"></div></td> <td><div class="clickDiv green" madde="line[2]"></div></td> </tr> </table> <label for="line1red"><input id="line1red" type="radio" name="line[1]" value="red" /> Red</label> <label for="line1green"><input id="line1green" type="radio" name="line[1]" value="green" /> Green</label><br /> <label for="line2red"><input type="radio" name="line[2]" value="red" /> Red</label> <label for="line2green"><input type="radio" name="line[2]" value="green" /> Green</label> </form> </body> </html> This doesn't. I need input names as an array but it breaks my script. Why?

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  • How can I save a directory tree to an array in PHP?

    - by Greg
    I'm trying to take a directory with the structure: top folder1 file1 folder2 file1 file2 And save it into an array like: array ( 'folder1' => array('file1'), 'folder2' => array('file1', 'file2') ) This way, I can easily resuse the tree throughout my site. I've been playing around with this code but it's still not doing what I want: private function get_tree() { $uploads = __RELPATH__ . DS . 'public' . DS . 'uploads'; $iterator = new RecursiveIteratorIterator(new RecursiveDirectoryIterator($uploads), RecursiveIteratorIterator::SELF_FIRST); $output = array(); foreach($iterator as $file) { $relativePath = str_replace($uploads . DS, '', $file); if ($file->isDir()) { if (!in_array($relativePath, $output)) $output[$relativePath] = array(); } } return $output; }

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  • How to send an array(multidimensional/associative) and some varaibles together through json?

    - by I Like PHP
    i have an multidimensional array $ouptput=Array ( [0] => Array ( [0] => mov_1 [1] => MY FAIR LADY ) [1] => Array ( [1] => mov_10 [2] => love actually ) ) and two variables $avlblQnty=50 $success= true when i send these data via json echo json_encode( array('movieData'=>$output,'stock'=>$avlblQnty,'sucess'=>$success)); it returns {"movieData":[["mov_1","MY FAIR LAD],{"1":"mov_10","2":"love actually"}],"stock":0,"success":true} but i need json encoded data properly so that i can create an select box on movieData using(movieData.length), so for that i want json edcoded data in below format so that i can retrive successfully {"movieData":[{"mov_1":"MY FAIR LAD,mov_10":"love actually"}],"stock":0,"success":true} i want to know how to send an array(multidimensional/associative) and some varaibles together through json?

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  • How can i initialize an array without knowing it size?

    - by Sara
    I have a situation where i have to apply a criteria on an input array and reuturn another array as output which will have smaller size based upon the filtering criteria. Now problem is i do not know the size of filtered results, so i can not initialize the array with specific value. And i do not want it to be large size will null values because i am using array.length; later on. One way is to first loop the original input array and set a counter, and then make another loop with that counter length and initialize and fill this array[]. But is there anyway to do the job in just one loop?

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  • How do I tell gdb how long my zero-length array is?

    - by Joe
    Slightly oxymoronic title! Bonus points for Xcode answer but it's a gdb question. If I have a standard, statically sized array gdb will print all its elements [and Xcode will let me browse through it] but if I have a zero length array, it won't, because it doesn't know. Obviously I can print the array indexes one by one, but I'd like a dump of the whole thing. How do I tell gdb how much space I have allocated for the array to allow it to print the array (or to allow Xcode to view the array). Is it even possible?

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  • Array from HTML forms - Internal Server Error

    - by user1392411
    I try to make a requestform for our school. But if I transmit this form I get a "Internal Server Error". I searched but I found nothing like that. Also I don't get a only this error message "Internal Server Error", nothing more. Any ideas why? <!DOCTYPE html> <html> <head> <title></title> <meta charset="utf-8"> <meta name="description" content=""> <link rel="stylesheet" href="../css/normalize.css" /> <link rel="stylesheet" href="../css/bestellformular.css" /> <!-- HTML 5 in Internet Explorer 9 und kleiner aktivieren --> <!--[if lt IE 9]> <script type="textt/javascript" src="js/html5shiv.js"></script> <![endif]--> </head> <body> <section id="head"> </section> <form action="../php/einlesen.php" method="post"> <section id="body"> <h1>Bestellung</h1> <table> <colgroup> <col width="10%"> <col width="80%"> <col width="10%"> </colgroup> <tr> <th> Artikel-Nr. </th> <th> Artikel </th> <th> Menge </th> </tr> <tr> <td> <input type="number" placeholder="Artikel-Nr." name="articelnr[]" required /> </td> <td> <input type="text" placeholder="Name des Artikels" name="articelname[]" required /> </td> <td> <input type="number" placeholder="Menge" name="quantity[]" required /> </td> </tr> <tr> <td> <input type="number" name="articelnr[]" /> </td> <td> <input type="text" name="articelname[]" /> </td> <td> <input type="number" name="quantity[]"/> </td> </tr> <tr> <td> <input type="number" name="articelnr[]" /> </td> <td> <input type="text" name="articelname[]" /> </td> <td> <input type="number" name="quantity[]"/> </td> </tr> <tr> <td> <input type="number" name="articelnr[]" /> </td> <td> <input type="text" name="articelname[]" /> </td> <td> <input type="number" name="quantity[]"/> </td> </tr> <tr> <td> <input type="number" name="articelnr[]" /> </td> <td> <input type="text" name="articelname[]" /> </td> <td> <input type="number" name="quantity[]"/> </td> </tr> <tr> <td> <input type="number" name="articelnr[]" /> </td> <td> <input type="text" name="articelname[]" /> </td> <td> <input type="number" name="quantity[]"/> </td> </tr> <tr> <td> <input type="number" name="articelnr[]" /> </td> <td> <input type="text" name="articelname[]" /> </td> <td> <input type="number" name="quantity[]"/> </td> </tr> <tr> <td> <input type="number" name="articelnr[]" /> </td> <td> <input type="text" name="articelname[]" /> </td> <td> <input type="number" name="quantity[]"/> </td> </tr> <tr> <td> <input type="number" name="articelnr[]" /> </td> <td> <input type="text" name="articelname[]" /> </td> <td> <input type="number" name="quantity[]"/> </td> </tr> <tr> <td> <input type="number" name="articelnr[]" /> </td> <td> <input type="text" name="articelname[]" /> </td> <td> <input type="number" name="quantity[]"/> </td> </tr> <tr> <td> <input type="number" name="articelnr[]" /> </td> <td> <input type="text" name="articelname[]" /> </td> <td> <input type="number" name="quantity[]"/> </td> </tr> <tr> <td> <input type="number" name="articelnr[]" /> </td> <td> <input type="text" name="articelname[]" /> </td> <td> <input type="number" name="quantity[]"/> </td> </tr> </table> </section> <section id="info"> <div class="left"> <hr /> <p> Kundennummer <input type="text" /> </p> </div> <div class="right"> <table> <tr> <td>Firma</td> <td><input type="text" name="company"required /></td> </tr> <tr> <td>Ort, PLZ</td> <td><input type="text" name="place" required /></td> <td><input type="number" name="plz" class="number" required /></td> </tr> <tr> <td>Straße, Nr.</td> <td><input type="text" name="street"required /></td> <td><input type="number" name="streetnr" class="number" required /></td> </tr> <tr> <td>Telefon</td> <td><input type="tel" name="tel" required /></td> </tr> <tr> <td>Fax</td> <td><input type="text" name="fax" required /></td> </tr> <tr> <td>E-Mail</td> <td><input type="email" name="email" required /></td> </tr> <tr> <td>Datum</td> <td><input type="date" name="date" required placeholder="tt.mm.jj"/></td> </tr> </table> </div> </section> <section id="submit"> <input type="checkbox" name="agb" required /> Ich habe die <a href="../docs/agb.pdf">AGB</a> gelesen und akzeptiere diese. <input type="submit" value="Bestellung Abschicken"/> </section> </form> <section id="footer"> <hr /> </section> </body> </html> Any Ideas why? The data is sent to a yet empty PHP document. The bracelets in the name tag are used to get an array. My PHP version is 5.3.8

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  • Can't seem to get C TCP Server-Client Communications Right

    - by Zeesponge
    Ok i need some serious help here. I have to make a TCP Server Client. When the Client connects to server using a three stage handshake. AFterwards... while the Client is running in the terminal, the user enters linux shell commands like xinput list, ls -1, ect... something that uses standard output. The server accepts the commands and uses system() (in a fork() in an infinite loop) to run the commands and the standard output is redirected to the client, where the client prints out each line. Afterward the server sends a completion signal of "\377\n". In which the client goes back to the command prompt asking for a new command and closes its connection and exit()'s when inputting "quit". I know that you have to dup2() both the STDOUT_FILENO and STDERR_FILENO to the clients file descriptor {dup2(client_FD, STDOUT_FILENO). Everything works accept when it comes for the client to retrieve system()'s stdout and printing it out... all i get is a blank line with a blinking cursor (client waiting on stdin). I tried all kinds of different routes with no avail... If anyone can help out i would greatly appreciate it TCP SERVER CODE include #include <sys/socket.h> #include <stdio.h> #include <string.h> #include <netinet/in.h> #include <signal.h> #include <unistd.h> #include <stdlib.h> #include <errno.h> //Prototype void handle_client(int connect_fd); int main() { int server_sockfd, client_sockfd; socklen_t server_len, client_len; struct sockaddr_in server_address; struct sockaddr_in client_address; server_sockfd = socket(AF_INET, SOCK_STREAM, 0); server_address.sin_family = AF_INET; server_address.sin_addr.s_addr = htonl(INADDR_ANY); server_address.sin_port = htons(9734); server_len = sizeof(server_address); bind(server_sockfd, (struct sockaddr *)&server_address, server_len); /* Create a connection queue, ignore child exit details and wait for clients. */ listen(server_sockfd, 10); signal(SIGCHLD, SIG_IGN); while(1) { printf("server waiting\n"); client_len = sizeof(client_address); client_sockfd = accept(server_sockfd, (struct sockaddr *)&client_address, &client_len); if(fork() == 0) handle_client(client_sockfd); else close(client_sockfd); } } void handle_client(int connect_fd) { const char* remsh = "<remsh>\n"; const char* ready = "<ready>\n"; const char* ok = "<ok>\n"; const char* command = "<command>\n"; const char* complete = "<\377\n"; const char* shared_secret = "<shapoopi>\n"; static char server_msg[201]; static char client_msg[201]; static char commands[201]; int sys_return; //memset client_msg, server_msg, commands memset(&client_msg, 0, sizeof(client_msg)); memset(&server_msg, 0, sizeof(client_msg)); memset(&commands, 0, sizeof(commands)); //read remsh from client read(connect_fd, &client_msg, 200); //check remsh validity from client if(strcmp(client_msg, remsh) != 0) { errno++; perror("Error Establishing Handshake"); close(connect_fd); exit(1); } //memset client_msg memset(&client_msg, 0, sizeof(client_msg)); //write remsh to client write(connect_fd, remsh, strlen(remsh)); //read shared_secret from client read(connect_fd, &client_msg, 200); //check shared_secret validity from client if(strcmp(client_msg, shared_secret) != 0) { errno++; perror("Invalid Security Passphrase"); write(connect_fd, "no", 2); close(connect_fd); exit(1); } //memset client_msg memset(&client_msg, 0, sizeof(client_msg)); //write ok to client write(connect_fd, ok, strlen(ok)); // dup2 STDOUT_FILENO <= client fd, STDERR_FILENO <= client fd dup2(connect_fd, STDOUT_FILENO); dup2(connect_fd, STDERR_FILENO); //begin while... while read (client_msg) from server and >0 while(read(connect_fd, &client_msg, 200) > 0) { //check command validity from client if(strcmp(client_msg, command) != 0) { errno++; perror("Error, unable to retrieve data"); close(connect_fd); exit(1); } //memset client_msg memset(&client_msg, 0, sizeof(client_msg)); //write ready to client write(connect_fd, ready, strlen(ready)); //read commands from client read(connect_fd, &commands, 200); //run commands using system( ) sys_return = system(commands); //check success of system( ) if(sys_return < 0) { perror("Invalid Commands"); errno++; } //memset commands memset(commands, 0, sizeof(commands)); //write complete to client write(connect_fd, complete, sizeof(complete)); } } TCP CLIENT CODE #include <sys/types.h> #include <sys/socket.h> #include <stdio.h> #include <string.h> #include <netinet/in.h> #include <arpa/inet.h> #include <unistd.h> #include <stdlib.h> #include <errno.h> #include "readline.c" int main(int argc, char *argv[]) { int sockfd; int len; struct sockaddr_in address; int result; const char* remsh = "<remsh>\n"; const char* ready = "<ready>\n"; const char* ok = "<ok>\n"; const char* command = "<command>\n"; const char* complete = "<\377\n"; const char* shared_secret = "<shapoopi>\n"; static char server_msg[201]; static char client_msg[201]; memset(&client_msg, 0, sizeof(client_msg)); memset(&server_msg, 0, sizeof(server_msg)); /* Create a socket for the client. */ sockfd = socket(AF_INET, SOCK_STREAM, 0); /* Name the socket, as agreed with the server. */ memset(&address, 0, sizeof(address)); address.sin_family = AF_INET; address.sin_addr.s_addr = inet_addr(argv[1]); address.sin_port = htons(9734); len = sizeof(address); /* Now connect our socket to the server's socket. */ result = connect(sockfd, (struct sockaddr *)&address, len); if(result == -1) { perror("ACCESS DENIED"); exit(1); } //write remsh to server write(sockfd, remsh, strlen(remsh)); //read remsh from server read(sockfd, &server_msg, 200); //check remsh validity from server if(strcmp(server_msg, remsh) != 0) { errno++; perror("Error Establishing Initial Handshake"); close(sockfd); exit(1); } //memset server_msg memset(&server_msg, 0, sizeof(server_msg)); //write shared secret text to server write(sockfd, shared_secret, strlen(shared_secret)); //read ok from server read(sockfd, &server_msg, 200); //check ok velidity from server if(strcmp(server_msg, ok) != 0 ) { errno++; perror("Incorrect security phrase"); close(sockfd); exit(1); } //? dup2 STDIN_FILENO = server socket fd? //dup2(sockfd, STDIN_FILENO); //begin while(1)/////////////////////////////////////// while(1){ //memset both msg arrays memset(&client_msg, 0, sizeof(client_msg)); memset(&server_msg, 0, sizeof(server_msg)); //print Enter Command, scan input, fflush to stdout printf("<<Enter Command>> "); scanf("%s", client_msg); fflush(stdout); //check quit input, if true close and exit successfully if(strcmp(client_msg, "quit") == 0) { printf("Exiting\n"); close(sockfd); exit(EXIT_SUCCESS); } //write command to server write(sockfd, command, strlen(command)); //read ready from server read(sockfd, &server_msg, 200); //check ready validity from server if(strcmp(server_msg, ready) != 0) { errno++; perror("Failed Server Communications"); close(sockfd); exit(1); } //memset server_msg memset(&server_msg, 0, sizeof(server_msg)); //begin looping and retrieving from stdin, //break loop at EOF or complete while((read(sockfd, server_msg, 200) != 0) && (strcmp(server_msg, complete) != 0)) { //while((fgets(server_msg, 4096, stdin) != EOF) || (strcmp(server_msg, complete) == 0)) { printf("%s", server_msg); memset(&server_msg, 0, sizeof(server_msg)); } } }

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  • Inside the Concurrent Collections: ConcurrentDictionary

    - by Simon Cooper
    Using locks to implement a thread-safe collection is rather like using a sledgehammer - unsubtle, easy to understand, and tends to make any other tool redundant. Unlike the previous two collections I looked at, ConcurrentStack and ConcurrentQueue, ConcurrentDictionary uses locks quite heavily. However, it is careful to wield locks only where necessary to ensure that concurrency is maximised. This will, by necessity, be a higher-level look than my other posts in this series, as there is quite a lot of code and logic in ConcurrentDictionary. Therefore, I do recommend that you have ConcurrentDictionary open in a decompiler to have a look at all the details that I skip over. The problem with locks There's several things to bear in mind when using locks, as encapsulated by the lock keyword in C# and the System.Threading.Monitor class in .NET (if you're unsure as to what lock does in C#, I briefly covered it in my first post in the series): Locks block threads The most obvious problem is that threads waiting on a lock can't do any work at all. No preparatory work, no 'optimistic' work like in ConcurrentQueue and ConcurrentStack, nothing. It sits there, waiting to be unblocked. This is bad if you're trying to maximise concurrency. Locks are slow Whereas most of the methods on the Interlocked class can be compiled down to a single CPU instruction, ensuring atomicity at the hardware level, taking out a lock requires some heavy lifting by the CLR and the operating system. There's quite a bit of work required to take out a lock, block other threads, and wake them up again. If locks are used heavily, this impacts performance. Deadlocks When using locks there's always the possibility of a deadlock - two threads, each holding a lock, each trying to aquire the other's lock. Fortunately, this can be avoided with careful programming and structured lock-taking, as we'll see. So, it's important to minimise where locks are used to maximise the concurrency and performance of the collection. Implementation As you might expect, ConcurrentDictionary is similar in basic implementation to the non-concurrent Dictionary, which I studied in a previous post. I'll be using some concepts introduced there, so I recommend you have a quick read of it. So, if you were implementing a thread-safe dictionary, what would you do? The naive implementation is to simply have a single lock around all methods accessing the dictionary. This would work, but doesn't allow much concurrency. Fortunately, the bucketing used by Dictionary allows a simple but effective improvement to this - one lock per bucket. This allows different threads modifying different buckets to do so in parallel. Any thread making changes to the contents of a bucket takes the lock for that bucket, ensuring those changes are thread-safe. The method that maps each bucket to a lock is the GetBucketAndLockNo method: private void GetBucketAndLockNo( int hashcode, out int bucketNo, out int lockNo, int bucketCount) { // the bucket number is the hashcode (without the initial sign bit) // modulo the number of buckets bucketNo = (hashcode & 0x7fffffff) % bucketCount; // and the lock number is the bucket number modulo the number of locks lockNo = bucketNo % m_locks.Length; } However, this does require some changes to how the buckets are implemented. The 'implicit' linked list within a single backing array used by the non-concurrent Dictionary adds a dependency between separate buckets, as every bucket uses the same backing array. Instead, ConcurrentDictionary uses a strict linked list on each bucket: This ensures that each bucket is entirely separate from all other buckets; adding or removing an item from a bucket is independent to any changes to other buckets. Modifying the dictionary All the operations on the dictionary follow the same basic pattern: void AlterBucket(TKey key, ...) { int bucketNo, lockNo; 1: GetBucketAndLockNo( key.GetHashCode(), out bucketNo, out lockNo, m_buckets.Length); 2: lock (m_locks[lockNo]) { 3: Node headNode = m_buckets[bucketNo]; 4: Mutate the node linked list as appropriate } } For example, when adding another entry to the dictionary, you would iterate through the linked list to check whether the key exists already, and add the new entry as the head node. When removing items, you would find the entry to remove (if it exists), and remove the node from the linked list. Adding, updating, and removing items all follow this pattern. Performance issues There is a problem we have to address at this point. If the number of buckets in the dictionary is fixed in the constructor, then the performance will degrade from O(1) to O(n) when a large number of items are added to the dictionary. As more and more items get added to the linked lists in each bucket, the lookup operations will spend most of their time traversing a linear linked list. To fix this, the buckets array has to be resized once the number of items in each bucket has gone over a certain limit. (In ConcurrentDictionary this limit is when the size of the largest bucket is greater than the number of buckets for each lock. This check is done at the end of the TryAddInternal method.) Resizing the bucket array and re-hashing everything affects every bucket in the collection. Therefore, this operation needs to take out every lock in the collection. Taking out mutiple locks at once inevitably summons the spectre of the deadlock; two threads each hold a lock, and each trying to acquire the other lock. How can we eliminate this? Simple - ensure that threads never try to 'swap' locks in this fashion. When taking out multiple locks, always take them out in the same order, and always take out all the locks you need before starting to release them. In ConcurrentDictionary, this is controlled by the AcquireLocks, AcquireAllLocks and ReleaseLocks methods. Locks are always taken out and released in the order they are in the m_locks array, and locks are all released right at the end of the method in a finally block. At this point, it's worth pointing out that the locks array is never re-assigned, even when the buckets array is increased in size. The number of locks is fixed in the constructor by the concurrencyLevel parameter. This simplifies programming the locks; you don't have to check if the locks array has changed or been re-assigned before taking out a lock object. And you can be sure that when a thread takes out a lock, another thread isn't going to re-assign the lock array. This would create a new series of lock objects, thus allowing another thread to ignore the existing locks (and any threads controlling them), breaking thread-safety. Consequences of growing the array Just because we're using locks doesn't mean that race conditions aren't a problem. We can see this by looking at the GrowTable method. The operation of this method can be boiled down to: private void GrowTable(Node[] buckets) { try { 1: Acquire first lock in the locks array // this causes any other thread trying to take out // all the locks to block because the first lock in the array // is always the one taken out first // check if another thread has already resized the buckets array // while we were waiting to acquire the first lock 2: if (buckets != m_buckets) return; 3: Calculate the new size of the backing array 4: Node[] array = new array[size]; 5: Acquire all the remaining locks 6: Re-hash the contents of the existing buckets into array 7: m_buckets = array; } finally { 8: Release all locks } } As you can see, there's already a check for a race condition at step 2, for the case when the GrowTable method is called twice in quick succession on two separate threads. One will successfully resize the buckets array (blocking the second in the meantime), when the second thread is unblocked it'll see that the array has already been resized & exit without doing anything. There is another case we need to consider; looking back at the AlterBucket method above, consider the following situation: Thread 1 calls AlterBucket; step 1 is executed to get the bucket and lock numbers. Thread 2 calls GrowTable and executes steps 1-5; thread 1 is blocked when it tries to take out the lock in step 2. Thread 2 re-hashes everything, re-assigns the buckets array, and releases all the locks (steps 6-8). Thread 1 is unblocked and continues executing, but the calculated bucket and lock numbers are no longer valid. Between calculating the correct bucket and lock number and taking out the lock, another thread has changed where everything is. Not exactly thread-safe. Well, a similar problem was solved in ConcurrentStack and ConcurrentQueue by storing a local copy of the state, doing the necessary calculations, then checking if that state is still valid. We can use a similar idea here: void AlterBucket(TKey key, ...) { while (true) { Node[] buckets = m_buckets; int bucketNo, lockNo; GetBucketAndLockNo( key.GetHashCode(), out bucketNo, out lockNo, buckets.Length); lock (m_locks[lockNo]) { // if the state has changed, go back to the start if (buckets != m_buckets) continue; Node headNode = m_buckets[bucketNo]; Mutate the node linked list as appropriate } break; } } TryGetValue and GetEnumerator And so, finally, we get onto TryGetValue and GetEnumerator. I've left these to the end because, well, they don't actually use any locks. How can this be? Whenever you change a bucket, you need to take out the corresponding lock, yes? Indeed you do. However, it is important to note that TryGetValue and GetEnumerator don't actually change anything. Just as immutable objects are, by definition, thread-safe, read-only operations don't need to take out a lock because they don't change anything. All lockless methods can happily iterate through the buckets and linked lists without worrying about locking anything. However, this does put restrictions on how the other methods operate. Because there could be another thread in the middle of reading the dictionary at any time (even if a lock is taken out), the dictionary has to be in a valid state at all times. Every change to state has to be made visible to other threads in a single atomic operation (all relevant variables are marked volatile to help with this). This restriction ensures that whatever the reading threads are doing, they never read the dictionary in an invalid state (eg items that should be in the collection temporarily removed from the linked list, or reading a node that has had it's key & value removed before the node itself has been removed from the linked list). Fortunately, all the operations needed to change the dictionary can be done in that way. Bucket resizes are made visible when the new array is assigned back to the m_buckets variable. Any additions or modifications to a node are done by creating a new node, then splicing it into the existing list using a single variable assignment. Node removals are simply done by re-assigning the node's m_next pointer. Because the dictionary can be changed by another thread during execution of the lockless methods, the GetEnumerator method is liable to return dirty reads - changes made to the dictionary after GetEnumerator was called, but before the enumeration got to that point in the dictionary. It's worth listing at this point which methods are lockless, and which take out all the locks in the dictionary to ensure they get a consistent view of the dictionary: Lockless: TryGetValue GetEnumerator The indexer getter ContainsKey Takes out every lock (lockfull?): Count IsEmpty Keys Values CopyTo ToArray Concurrent principles That covers the overall implementation of ConcurrentDictionary. I haven't even begun to scratch the surface of this sophisticated collection. That I leave to you. However, we've looked at enough to be able to extract some useful principles for concurrent programming: Partitioning When using locks, the work is partitioned into independant chunks, each with its own lock. Each partition can then be modified concurrently to other partitions. Ordered lock-taking When a method does need to control the entire collection, locks are taken and released in a fixed order to prevent deadlocks. Lockless reads Read operations that don't care about dirty reads don't take out any lock; the rest of the collection is implemented so that any reading thread always has a consistent view of the collection. That leads us to the final collection in this little series - ConcurrentBag. Lacking a non-concurrent analogy, it is quite different to any other collection in the class libraries. Prepare your thinking hats!

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  • How to use a list of values in Excel as filter in a query

    - by Luca Zavarella
    It often happens that a customer provides us with a list of items for which to extract certain information. Imagine, for example, that our clients wish to have the header information of the sales orders only for certain orders. Most likely he will give us a list of items in a column in Excel, or, less probably, a simple text file with the identification code:     As long as the given values ??are at best a dozen, it costs us nothing to copy and paste those values ??in our SSMS and place them in a WHERE clause, using the IN operator, making sure to include the quotes in the case of alphanumeric elements (the database sample is AdventureWorks2008R2): SELECT * FROM Sales.SalesOrderHeader AS SOH WHERE SOH.SalesOrderNumber IN ( 'SO43667' ,'SO43709' ,'SO43726' ,'SO43746' ,'SO43782' ,'SO43796') Clearly, the need to add commas and quotes becomes an hassle when dealing with hundreds of items (which of course has happened to us!). It’d be comfortable to do a simple copy and paste, leaving the items as they are pasted, and make sure the query works fine. We can have this commodity via a User Defined Function, that returns items in a table. Simply we’ll provide the function with an input string parameter containing the pasted items. I give you directly the T-SQL code, where comments are there to clarify what was written: CREATE FUNCTION [dbo].[SplitCRLFList] (@List VARCHAR(MAX)) RETURNS @ParsedList TABLE ( --< Set the item length as your needs Item VARCHAR(255) ) AS BEGIN DECLARE --< Set the item length as your needs @Item VARCHAR(255) ,@Pos BIGINT --< Trim TABs due to indentations SET @List = REPLACE(@List, CHAR(9), '') --< Trim leading and trailing spaces, then add a CR\LF at the end of the list SET @List = LTRIM(RTRIM(@List)) + CHAR(13) + CHAR(10) --< Set the position at the first CR/LF in the list SET @Pos = CHARINDEX(CHAR(13) + CHAR(10), @List, 1) --< If exist other chars other than CR/LFs in the list then... IF REPLACE(@List, CHAR(13) + CHAR(10), '') <> '' BEGIN --< Loop while CR/LFs are over (not found = CHARINDEX returns 0) WHILE @Pos > 0 BEGIN --< Get the heading list chars from the first char to the first CR/LF and trim spaces SET @Item = LTRIM(RTRIM(LEFT(@List, @Pos - 1))) --< If the so calulated item is not empty... IF @Item <> '' BEGIN --< ...insert it in the @ParsedList temporary table INSERT INTO @ParsedList (Item) VALUES (@Item) --(CAST(@Item AS int)) --< Use the appropriate conversion if needed END --< Remove the first item from the list... SET @List = RIGHT(@List, LEN(@List) - @Pos - 1) --< ...and set the position to the next CR/LF SET @Pos = CHARINDEX(CHAR(13) + CHAR(10), @List, 1) --< Repeat this block while the upon loop condition is verified END END RETURN END At this point, having created the UDF, our query is transformed trivially in: SELECT * FROM Sales.SalesOrderHeader AS SOH WHERE SOH.SalesOrderNumber IN ( SELECT Item FROM SplitCRLFList('SO43667 SO43709 SO43726 SO43746 SO43782 SO43796') AS SCL) Convenient, isn’t it? You can find the script DBA_SplitCRLFList.sql here. Bye!!

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  • Best way to grow Linux software RAID 1 to RAID 10

    - by Hans Malherbe
    mdadm does not seem to support growing an array from level 1 to level 10. I have two disks in RAID 1. I want to add two new disks and convert the array to a four disk RAID 10 array. My current strategy: Make good backup. Create a degraded 4 disk RAID 10 array with two missing disks. rsync the RAID 1 array with the RAID 10 array. fail and remove one disk from the RAID 1 array. Add the available disk to the RAID 10 array and wait for resynch to complete. Destroy the RAID 1 array and add the last disk to the RAID 10 array. The problem is the lack of redundancy at step 5. Is there a better way?

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  • Best way to grow Linux software RAID 1 to RAID 10

    - by Hans Malherbe
    mdadm does not seem to support growing an array from level 1 to level 10. I have two disks in RAID 1. I want to add two new disks and convert the array to a four disk RAID 10 array. My current strategy: Make good backup. Create a degraded 4 disk RAID 10 array with two missing disks. rsync the RAID 1 array with the RAID 10 array. fail and remove one disk from the RAID 1 array. Add the available disk to the RAID 10 array and wait for resynch to complete. Destroy the RAID 1 array and add the last disk to the RAID 10 array. The problem is the lack of redundancy at step 5. Is there a better way?

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  • In an Entity/Component system, can component data be implemented as a simple array of key-value pairs? [on hold]

    - by 010110110101
    I'm trying to wrap my head around how to organize components in an Entity Component Systems once everything in the current scene/level is loaded in memory. (I'm a hobbyist BTW) Some people seem to implement the Entity as an object that contains a list of of "Component" objects. Components contain data organized as an array of key-value pairs. Where the value is serialized "somehow". (pseudocode is loosely in C# for brevity) class Entity { Guid _id; List<Component> _components; } class Component { List<ComponentAttributeValue> _attributes; } class ComponentAttributeValue { string AttributeName; object AttributeValue; } Others describe Components as an in-memory "table". An entity acquires the component by having its key placed in a table. The attributes of the component-entity instance are like the columns in a table class Renderable_Component { List<RenderableComponentAttributeValue> _entities; } class RenderableComponentAttributeValue { Guid entityId; matrix4 transformation; // other stuff for rendering // everything is strongly typed } Others describe this actually as a table. (and such tables sound like an EAV database schema BTW) (and the value is serialized "somehow") Render_Component_Table ---------------- Entity Id Attribute Name Attribute Value and when brought into running code: class Entity { Guid _id; Dictionary<string, object> _attributes; } My specific question is: Given various components, (Renderable, Positionable, Explodeable, Hideable, etc) and given that each component has an attribute with a particular name, (TRANSLATION_MATRIX, PARTICLE_EMISSION_VELOCITY, CAN_HIDE, FAVORITE_COLOR, etc) should: an entity contain a list of components where each component, in turn, has their own array of named attributes with values serialized somehow or should components exist as in-memory tables of entity references and associated with each "row" there are "columns" representing the attribute with values that are specific to each entity instance and are strongly typed or all attributes be stored in an entity as a singular array of named attributes with values serialized somehow (could have name collisions) or something else???

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  • how to generate random bubbles from array of sprites in cocos2d?

    - by prakash s
    I am devoloping the bubble shooter game in cocos2d how to generate random bubbles from array of sprites here is my code (void)addTarget { CGSize winSize = [[CCDirector sharedDirector] winSize]; //CCSprite *target = [CCSprite spriteWithFile:@"3.png" rect:CGRectMake(0, 0, 256, 256)]; NSMutableArray * movableSprites = [[NSMutableArray alloc] init]; NSArray *images = [NSArray arrayWithObjects:@"1.png", @"2.png", @"3.png", @"4.png",@"5.png",@"1.png",@"5.png", @"3.png", nil]; for(int i = 0; i < images.count; ++i) { NSString *image = [images objectAtIndex:i]; // generate random number based on size of array (array size is larger than 10) CCSprite*target = [CCSprite spriteWithFile:image]; float offsetFraction = ((float)(i+1))/(images.count+1); target.position = ccp(winSize.width*offsetFraction, winSize.height/2); target.position = ccp(350*offsetFraction, 460); [self addChild:target]; [movableSprites addObject:target]; //[target runAction:]; id actionMove = [CCMoveTo actionWithDuration:10 position:ccp(winSize.width/2,winSize. height/2)]; This code generating bubbles with *.png colour bubbles but i want to generate randomly because for shooting the bubbles by shooter class help me please id actionMoveDone = [CCCallFuncN actionWithTarget:self selector:@selector(spriteMoveFinished:)]; [target runAction:[CCSequence actions:actionMove, actionMoveDone, nil]]; } }

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  • Building an interleaved buffer for pyopengl and numpy

    - by Nick Sonneveld
    I'm trying to batch up a bunch of vertices and texture coords in an interleaved array before sending it to pyOpengl's glInterleavedArrays/glDrawArrays. The only problem is that I'm unable to find a suitably fast enough way to append data into a numpy array. Is there a better way to do this? I would have thought it would be quicker to preallocate the array and then fill it with data but instead, generating a python list and converting it to a numpy array is "faster". Although 15ms for 4096 quads seems slow. I have included some example code and their timings. #!/usr/bin/python import timeit import numpy import ctypes import random USE_RANDOM=True USE_STATIC_BUFFER=True STATIC_BUFFER = numpy.empty(4096*20, dtype=numpy.float32) def render(i): # pretend these are different each time if USE_RANDOM: tex_left, tex_right, tex_top, tex_bottom = random.random(), random.random(), random.random(), random.random() left, right, top, bottom = random.random(), random.random(), random.random(), random.random() else: tex_left, tex_right, tex_top, tex_bottom = 0.0, 1.0, 1.0, 0.0 left, right, top, bottom = -1.0, 1.0, 1.0, -1.0 ibuffer = ( tex_left, tex_bottom, left, bottom, 0.0, # Lower left corner tex_right, tex_bottom, right, bottom, 0.0, # Lower right corner tex_right, tex_top, right, top, 0.0, # Upper right corner tex_left, tex_top, left, top, 0.0, # upper left ) return ibuffer # create python list.. convert to numpy array at end def create_array_1(): ibuffer = [] for x in xrange(4096): data = render(x) ibuffer += data ibuffer = numpy.array(ibuffer, dtype=numpy.float32) return ibuffer # numpy.array, placing individually by index def create_array_2(): if USE_STATIC_BUFFER: ibuffer = STATIC_BUFFER else: ibuffer = numpy.empty(4096*20, dtype=numpy.float32) index = 0 for x in xrange(4096): data = render(x) for v in data: ibuffer[index] = v index += 1 return ibuffer # using slicing def create_array_3(): if USE_STATIC_BUFFER: ibuffer = STATIC_BUFFER else: ibuffer = numpy.empty(4096*20, dtype=numpy.float32) index = 0 for x in xrange(4096): data = render(x) ibuffer[index:index+20] = data index += 20 return ibuffer # using numpy.concat on a list of ibuffers def create_array_4(): ibuffer_concat = [] for x in xrange(4096): data = render(x) # converting makes a diff! data = numpy.array(data, dtype=numpy.float32) ibuffer_concat.append(data) return numpy.concatenate(ibuffer_concat) # using numpy array.put def create_array_5(): if USE_STATIC_BUFFER: ibuffer = STATIC_BUFFER else: ibuffer = numpy.empty(4096*20, dtype=numpy.float32) index = 0 for x in xrange(4096): data = render(x) ibuffer.put( xrange(index, index+20), data) index += 20 return ibuffer # using ctype array CTYPES_ARRAY = ctypes.c_float*(4096*20) def create_array_6(): ibuffer = [] for x in xrange(4096): data = render(x) ibuffer += data ibuffer = CTYPES_ARRAY(*ibuffer) return ibuffer def equals(a, b): for i,v in enumerate(a): if b[i] != v: return False return True if __name__ == "__main__": number = 100 # if random, don't try and compare arrays if not USE_RANDOM and not USE_STATIC_BUFFER: a = create_array_1() assert equals( a, create_array_2() ) assert equals( a, create_array_3() ) assert equals( a, create_array_4() ) assert equals( a, create_array_5() ) assert equals( a, create_array_6() ) t = timeit.Timer( "testing2.create_array_1()", "import testing2" ) print 'from list:', t.timeit(number)/number*1000.0, 'ms' t = timeit.Timer( "testing2.create_array_2()", "import testing2" ) print 'array: indexed:', t.timeit(number)/number*1000.0, 'ms' t = timeit.Timer( "testing2.create_array_3()", "import testing2" ) print 'array: slicing:', t.timeit(number)/number*1000.0, 'ms' t = timeit.Timer( "testing2.create_array_4()", "import testing2" ) print 'array: concat:', t.timeit(number)/number*1000.0, 'ms' t = timeit.Timer( "testing2.create_array_5()", "import testing2" ) print 'array: put:', t.timeit(number)/number*1000.0, 'ms' t = timeit.Timer( "testing2.create_array_6()", "import testing2" ) print 'ctypes float array:', t.timeit(number)/number*1000.0, 'ms' Timings using random numbers: $ python testing2.py from list: 15.0486779213 ms array: indexed: 24.8184704781 ms array: slicing: 50.2214789391 ms array: concat: 44.1691994667 ms array: put: 73.5879898071 ms ctypes float array: 20.6674289703 ms edit note: changed code to produce random numbers for each render to reduce object reuse and to simulate different vertices each time. edit note2: added static buffer and force all numpy.empty() to use dtype=float32 note 1/Apr/2010: still no progress and I don't really feel that any of the answers have solved the problem yet.

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  • HttpServerUtility.UrlTokenDecode fails "sometimes" (Invalid length for a Base-64 char array.)

    - by Josef
    We have an IHttpHandler for stylesheets and add a <link/> tag to the page like this: HtmlGenericControl link = new HtmlGenericControl("link"); link.Attributes.Add("rel", "stylesheet"); link.Attributes.Add("href", "stylesheet.axd?d=" + HttpServerUtility.UrlTokenEncode(token)); head.Controls.Add(link); In the stylesheet.axd handler, we UrlTokenDecode the d query string parameter like this: var token = HttpServerUtility.UrlTokenDecode(Request.QueryString["d"]); This works most of the time but every now and then we find one of the following two exceptions in our log: [FormatException: Invalid character in a Base-64 string.] System.Convert.FromBase64CharArray(Char[] inArray, Int32 offset, Int32 length) System.Web.HttpServerUtility.UrlTokenDecode(String input) ... [FormatException: Invalid length for a Base-64 char array.] System.Convert.FromBase64CharArray(Char[] inArray, Int32 offset, Int32 length) System.Web.HttpServerUtility.UrlTokenDecode(String input) System.Web.HttpServerUtilityWrapper.UrlTokenDecode(String input) ... Any ideas what would cause this phenomenon? Remarks: the resulting URL is < 1500, so below any known URL limits (e.g. IE: 2083) seems to be independent of user agent (we have these exceptions for IE6,7,8, FF & Chrome) our (unconfirmed) suspicions include AntiVirus products, HTTP proxies, browser addons found this remotely related question, but it's about a viewstate issue

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  • How do I import and call unmanaged C dll with ansi string "char *" pointer string from VB.net?

    - by Warren P
    I have written my own function, which in C would be declared like this, using standard Win32 calling conventions: int Thing( char * command, char * buffer, int * BufSize); I have the following amount of VB figured out, which should import the dll and call this function, wrapping it up to make it easy to call Thing("CommandHere",GetDataBackHere): Imports Microsoft.VisualBasic Imports System.Runtime.InteropServices Imports System Imports System.Text Namespace dllInvocationSpace Public Class dllInvoker ' tried attributes but could not make it build: ' <DllImport("Thing1.dll", False, CallingConvention.Cdecl, CharSet.Ansi, "Baton", True, True, False, True)> Declare Ansi Function Thing Lib "Thing1.dll" (ByVal Command As String, ByRef Buffer As String, ByRef BufferLength As Integer) Shared Function dllCall(ByVal Command As String, ByRef Results As String) As Integer Dim Buffer As StringBuilder = New StringBuilder(65536) Dim retCode As Integer Dim bufsz As Integer bufsz = 65536 retCode = Thing(Command, Buffer, bufsz) Results = Buffer Return retCode End Function End Class End Namespace The current code doesn't build, because although I think I should be able to create a "buffer" that the C Dll can write data back into using a string builder, I haven't got it quite right. (Value of type System.Text.STringBuilder cannot be converted to 'String'). I have looked all over the newsgroups and forums and can not find an example where the C dll needs to pass between 1 and 64kbytes of data back (char *buffer, int bufferlen) to visual basic.net.

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  • Is there really such a thing as a char or short in modern programming?

    - by Dean P
    Howdy all, I've been learning to program for a Mac over the past few months (I have experience in other languages). Obviously that has meant learning the Objective C language and thus the plainer C it is predicated on. So I have stumbles on this quote, which refers to the C/C++ language in general, not just the Mac platform. With C and C++ prefer use of int over char and short. The main reason behind this is that C and C++ perform arithmetic operations and parameter passing at integer level, If you have an integer value that can fit in a byte, you should still consider using an int to hold the number. If you use a char, the compiler will first convert the values into integer, perform the operations and then convert back the result to char. So my question, is this the case in the Mac Desktop and IPhone OS environments? I understand when talking about theses environments we're actually talking about 3-4 different architectures (PPC, i386, Arm and the A4 Arm variant) so there may not be a single answer. Nevertheless does the general principle hold that in modern 32 bit / 64 bit systems using 1-2 byte variables that don't align with the machine's natural 4 byte words doesn't provide much of the efficiency we may expect. For instance, a plain old C-Array of 100,000 chars is smaller than the same 100,000 ints by a factor of four, but if during an enumeration, reading out each index involves a cast/boxing/unboxing of sorts, will we see overall lower 'performance' despite the saved memory overhead?

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  • CakePHP Multiple Nested Joins

    - by Paul
    I have an App in which several of the models are linked by hasMany/belongsTo associations. So for instance, A hasMany B, B hasMany C, C hasMany D, and D hasMany E. Also, E belongs to D, D belongs to C, C belongs to B, and B belongs to A. Using the Containable behavior has been great for controlling the amount of information comes back with each query, but I seem to be having a problem when trying to get data from table A while using a condition that involves table D. For instance, here is an example of my 'A' model: class A extends AppModel { var $name = 'A'; var $hasMany = array( 'B' => array('dependent' => true) ); function findDependentOnE($condition) { return $this->find('all', array( 'contain' => array( 'B' => array( 'C' => array( 'D' => array( 'E' => array( 'conditions' => array( 'E.myfield' => $some_value ) ) ) ) ) ) )); } } This still gives me back all the records in 'A', and if it's related 'E' records don't satisfy the condition, then I just get this: Array( [0] => array( [A] => array( [field1] => // stuff [field2] => // more stuff // ...etc ), [B] => array( [field1] => // stuff [field2] => // more stuff // ...etc ), [C] => array( [field1] => // stuff [field2] => // more stuff // ...etc ), [D] => array( [field1] => // stuff [field2] => // more stuff // ...etc ), [E] => array( // empty if 'E.myfield' != $some_value' ) ), [1] => array( // ...etc ) ) When If 'E.myfield' != $some_value, I don't want the record returned at all. I hope this expresses my problem clearly enough... Basically, I want the following query, but in a database-agnostic/CakePHP-y kind of way: SELECT * FROM A INNER JOIN (B INNER JOIN (C INNER JOIN (D INNER JOIN E ON D.id=E.d_id) ON C.id=D.c_id) ON B.id=C.b_id) ON A.id=B.a_id WHERE E.myfield = $some_value

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  • Correct way to use Drupal 7 Entities and Field API

    - by Martin Petts
    I'm trying to use Drupal 7's entities and field API to correctly build a new module. What I have been unable to understand from the documentation is the correct way to use the new API to create a 'content type' (not a node type) with a number of set fields, such as Body. I'm trying to set up the entity using hook_entity_info, then I believe I need to add the body field using field_create_instance, but I can't seem to get it to work. In mycontenttype.module: /** * Implements hook_entity_info(). */ function mycontenttype_entity_info() { $return = array( 'mycontenttype' => array( 'label' => t('My Content Type'), 'controller class' => 'MyContentTypeEntityController', 'base table' => 'content_type', 'uri callback' => 'content_type_uri', 'entity keys' => array( 'id' => 'cid', 'label' => 'title' ), 'bundles' => array( 'mycontenttype' => array( 'label' => 'My Content Type', 'admin' => array( 'path' => 'admin/contenttype', 'access arguments' => array('administer contenttype') ) ) ), 'fieldable' => true ) ); return $return; } /** * Implements hook_field_extra_fields(). */ function mycontenttype_field_extra_fields() { $return['mycontenttype']['mycontenttype'] = array( 'form' = array( 'body' = array( 'label' = 'Body', 'description' = t('Body content'), 'weight' = 0, ), ), ); return $return; } Then does this go in the .install file? function mycontenttype_install() { $field = array( 'field_name' => 'body', 'type' => 'text_with_summary', 'entity_types' => array('survey'), 'translatable' => TRUE, ); field_create_field($field); $instance = array( 'entity_type' => 'mycontenttype', 'field_name' => 'body', 'bundle' => 'mycontenttype', 'label' => 'Body', 'widget_type' => 'text_textarea_with_summary', 'settings' => array('display_summary' => TRUE), 'display' => array( 'default' => array( 'label' => 'hidden', 'type' => 'text_default', ), 'teaser' => array( 'label' => 'hidden', 'type' => 'text_summary_or_trimmed', ) ) ); field_create_instance($instance); }

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