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• Inode to device information

  - by Methos

  I have 3 questions: I want to figure out if a file belongs to a USB device given the file inode. By looking in the latest kernel sources (2.6.33) on LXR, I think one can find that information by following pointers as follows: inode-super_block-block_device-backing_dev_info-device-device_driver(or device_type). However, the kernel that I am working with - 2.6.22.14 - does not have struct device pointer in the backing_dev_info object. So how can I figure out to which device does a file belong to from just the inode? I see that each of the inode, super_block and block_device contain an object of type 'dev_t'. But even after searching a lot, I could not find out how to convert 'dev_t' into struct device *. Is there any way to get that infomation? I tried to print device major and minor numbers using imajor(inode) and iminor(inode). However, for every file - belonging to hdd or usb - it always prints major and minor number as zero. Why would that be happening? I searched online for USB major numbers and I found out that major number for a USB is 180. However, on multiple machines, it showed me the major number associated with the USB dev as 253. $ ls -ltr /dev/usb* crw-rw---- 1 root root 253, 4 2010-04-13 17:20 /dev/usbmon4 crw-rw---- 1 root root 253, 3 2010-04-13 17:20 /dev/usbmon3 crw-rw---- 1 root root 253, 8 2010-04-13 17:20 /dev/usbmon8 crw-rw---- 1 root root 253, 5 2010-04-13 17:20 /dev/usbmon5 crw-rw---- 1 root root 253, 1 2010-04-13 17:20 /dev/usbmon1 crw-rw---- 1 root root 253, 7 2010-04-13 17:20 /dev/usbmon7 Why is that so?

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• Sliding doors HTML buttons in Safari Win

  - by RyanP13

  Hi, I have the following HTML for buttons implementing sliding doors technique that look fine in everything but Safari on Windows: <button type="submit"> <span>Button</span> </button> This is the corresponding CSS: button { background:url("../images/sprBgBtn.png") no-repeat right -47px; border:0; cursor:pointer; font-weight:bold; height:27px; line-height:27px; overflow:visible; padding:0 26px 0 0; position:relative; text-align:center; text-transform:uppercase; width:auto; } button::-moz-focus-inner { border: none; /* overrides extra padding in Firefox */ padding:0; } button span { background:url("../images/sprBgBtn.png") no-repeat left top; display:block; height:27px; line-height:27px; padding:0 0 0 26px; position:relative; white-space:nowrap; } If i omit the following code then the same issue will appear in FFOX: button::-moz-focus-inner { border: none; /* overrides extra padding in Firefox */ padding:0; }

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• Save memory in Python. How to iterate over the lines and save them efficiently with a 2million line

  - by skyl

  I have a tab-separated data file with a little over 2 million lines and 19 columns. You can find it, in US.zip: http://download.geonames.org/export/dump/. I started to run the following but with for l in f.readlines(). I understand that just iterating over the file is supposed to be more efficient so I'm posting that below. Still, with this small optimization, I'm using 10% of my memory on the process and have only done about 3% of the records. It looks like, at this pace, it will run out of memory like it did before. Also, the function I have is very slow. Is there anything obvious I can do to speed it up? Would it help to del the objects with each pass of the for loop? def run(): from geonames.models import POI f = file('data/US.txt') for l in f: li = l.split('\t') try: p = POI() p.geonameid = li[0] p.name = li[1] p.asciiname = li[2] p.alternatenames = li[3] p.point = "POINT(%s %s)" % (li[5], li[4]) p.feature_class = li[6] p.feature_code = li[7] p.country_code = li[8] p.ccs2 = li[9] p.admin1_code = li[10] p.admin2_code = li[11] p.admin3_code = li[12] p.admin4_code = li[13] p.population = li[14] p.elevation = li[15] p.gtopo30 = li[16] p.timezone = li[17] p.modification_date = li[18] p.save() except IndexError: pass if __name__ == "__main__": run()

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• Pointers in C# to make int array?

  - by Joshua

  The following C++ program compiles and runs as expected: #include <stdio.h> int main(int argc, char* argv[]) { int* test = new int[10]; for (int i = 0; i < 10; i++) test[i] = i * 10; printf("%d \n", test[5]); // 50 printf("%d \n", 5[test]); // 50 return getchar(); } The closest C# simple example I could make for this question is: using System; class Program { unsafe static int Main(string[] args) { // error CS0029: Cannot implicitly convert type 'int[]' to 'int*' int* test = new int[10]; for (int i = 0; i < 10; i++) test[i] = i * 10; Console.WriteLine(test[5]); // 50 Console.WriteLine(5[test]); // Error return (int)Console.ReadKey().Key; } } So how do I make the pointer?

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• Do fluent interfaces significantly impact runtime performance of a .NET application?

  - by stakx

  I'm currently occupying myself with implementing a fluent interface for an existing technology, which would allow code similar to the following snippet: using (var directory = Open.Directory(@"path\to\some\directory")) { using (var file = Open.File("foobar.html").In(directory)) { // ... } } In order to implement such constructs, classes are needed that accumulate arguments and pass them on to other objects. For example, to implement the Open.File(...).In(...) construct, you would need two classes: // handles 'Open.XXX': public static class OpenPhrase { // handles 'Open.File(XXX)': public static OpenFilePhrase File(string filename) { return new OpenFilePhrase(filename); } // handles 'Open.Directory(XXX)': public static DirectoryObject Directory(string path) { // ... } } // handles 'Open.File(XXX).XXX': public class OpenFilePhrase { internal OpenFilePhrase(string filename) { _filename = filename } // handles 'Open.File(XXX).In(XXX): public FileObject In(DirectoryObject directory) { // ... } private readonly string _filename; } That is, the more constituent parts statements such as the initial examples have, the more objects need to be created for passing on arguments to subsequent objects in the chain until the actual statement can finally execute. Question: I am interested in some opinions: Does a fluent interface which is implemented using the above technique significantly impact the runtime performance of an application that uses it? With runtime performance, I refer to both speed and memory usage aspects. Bear in mind that a potentially large number of temporary, argument-saving objects would have to be created for only very brief timespans, which I assume may put a certain pressure on the garbage collector. If you think there is significant performance impact, do you know of a better way to implement fluent interfaces?

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• Performance degrades for more than 2 threads on Xeon X5355

  - by zoolii

  Hi All, I am writing an application using boost threads and using boost barriers to synchronize the threads. I have two machines to test the application. Machine 1 is a core2 duo (T8300) cpu machine (windows XP professional - 4GB RAM) where I am getting following performance figures : Number of threads :1 , TPS :21 Number of threads :2 , TPS :35 (66 % improvement) further increase in number of threads decreases the TPS but that is understandable as the machine has only two cores. Machine 2 is a 2 quad core ( Xeon X5355) cpu machine (windows 2003 server with 4GB RAM) and has 8 effective cores. Number of threads :1 , TPS :21 Number of threads :2 , TPS :27 (28 % improvement) Number of threads :4 , TPS :25 Number of threads :8 , TPS :24 As you can see, performance is degrading after 2 threads (though it has 8 cores). If the program has some bottle neck , then for 2 thread also it should have degraded. Any idea? , Explanations ? , Does the OS has some role in performance ? - It seems like the Core2duo (2.4GHz) scales better than Xeon X5355 (2.66GHz) though it has better clock speed. Thank you -Zoolii

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• Should I release NSString before assigning a new value to it?

  - by Elliot Chen

  Hi, Please give me some suggestions about how to change a NSString variable. At my class, I set a member var: NSString *m_movieName; ... @property(nonatomic, retain) NSString *m_movieName; At viewDidLoad method, I assign a default name to this var: -(void)viewDidLoad{ NSString *s1 = [[NSString alloc] initWithFormat:@"Forrest Gump"]; self.m_movieName = s1; ... [s1 release]; [super viewDidLoad] } At some function, I want to give a new name to this var, so I did like: -(void)SomeFunc{ NSString *s2 = [[NSString alloc] initWithFormat:@"Brave Heart"]; //[self.movieName release]; // ??????? Should perform here? self.m_moiveName = s2; [s2 release]; } I know, NSString* var is just a pointer to an allocated memory block, and 'assign' operation will increment this memory block's using count. For my situation, should I release m_movieName before assigning a value to it? If I do not release it (via [self.movieName release]), when and where will the previous block be released? Thanks for your help very much!

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• Generate and merge data with python multiprocessing

  - by Bobby

  I have a list of starting data. I want to apply a function to the starting data that creates a few pieces of new data for each element in the starting data. Some pieces of the new data are the same and I want to remove them. The sequential version is essentially: def create_new_data_for(datum): """make a list of new data from some old datum""" return [datum.modified_copy(k) for k in datum.k_list] data = [some list of data] #some data to start with #generate a list of new data from the old data, we'll reduce it next newdata = [] for d in data: newdata.extend(create_new_data_for(d)) #now reduce the data under ".matches(other)" reduced = [] for d in newdata: for seen in reduced: if d.matches(seen): break #so we haven't seen anything like d yet seen.append(d) #now reduced is finished and is what we want! I want to speed this up with multiprocessing. I was thinking that I could use a multiprocessing.Queue for the generation. Each process would just put the stuff it creates on, and when the processes are reducing the data, they can just get the data from the Queue. But I'm not sure how to have the different process loop over reduced and modify it without any race conditions or other issues. What is the best way to do this safely? or is there a different way to accomplish this goal better?

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• Any high-level languages that can use c libraries?

  - by Isaiah

  I know this question could be in vain, but it's just out of curiosity, and I'm still much a newb^^ Anyways I've been loving python for some time while learning it. My problem is obviously speed issues. I'd like to get into indie game creation, and for the short future, 2d and pygame will work. But I'd eventually like to branch into the 3d area, and python is really too slow to make anything 3d and professional. So I'm wondering if there has ever been work to create a high-level language able to import and use c libraries? I've looked at Genie and it seems to be able to use certain libraries, but I'm not sure to what extent. Will I be able to use it for openGL programing, or in a c game engine? I do know some lisp and enjoy it a lot, but there aren't a great many libraries out there for it. Which leads to the problem: I can't stand C syntax, but C has libraries galore that I could need! And game engines like irrlicht. Is there any language that can be used in place of C around C? Thanks so much guys

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• Getting size of a specific byte array from an array of pointers to bytes

  - by Pat James

  In the following example c code, used in an Arduino project, I am looking for the ability to get the size of a specific byte array within an array of pointers to bytes, for example void setup() { Serial.begin(9600); // for debugging byte zero[] = {8, 169, 8, 128, 2,171,145,155,141,177,187,187,2,152,2,8,134,199}; byte one[] = {8, 179, 138, 138, 177 ,2,146, 8, 134, 8, 194,2,1,14,199,7, 145, 8,131, 8,158,8,187,187,191}; byte two[] = {29,7,1,8, 169, 8, 128, 2,171,145,155,141,177,187,187,2,152,2,8,134,199, 2, 2, 8, 179, 138, 138, 177 ,2,146, 8, 134, 8, 194,2,1,14,199,7, 145, 8,131, 8,158,8,187,187,191}; byte* numbers[3] = {zero, one, two }; function(numbers[1], sizeof(numbers[1])/sizeof(byte)); //doesn't work as desired, always passes 2 as the length function(numbers[1], 25); //this works } void loop() { } void function( byte arr[], int len ) { Serial.print("length: "); Serial.println(len); for (int i=0; i<len; i++){ Serial.print("array element "); Serial.print(i); Serial.print(" has value "); Serial.println((int)arr[i]); } } In this code, I understand that sizeof(numbers1)/sizeof(byte)) doesn't work because numbers1 is a pointer and not the byte array value. Is there a way in this example that I can, at runtime, get at the length of a specific (runtime-determined) byte array within an array of pointers to bytes? Understand that I am limited to developing in c (or assembly) for an Arduino environment. Also open to other suggestions rather than the array of pointers to bytes. The overall objective is to organize lists of bytes which can be retrieved, with length, at runtime.

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• How to std::find using a Compare object?

  - by dehmann

  I am confused about the interface of std::find. Why doesn't it take a Compare object that tells it how to compare two objects? If I could pass a Compare object I could make the following code work, where I would like to compare by value, instead of just comparing the pointer values directly: typedef std::vector<std::string*> Vec; Vec vec; std::string* s1 = new std::string("foo"); std::string* s2 = new std::string("foo"); vec.push_back(s1); Vec::const_iterator found = std::find(vec.begin(), vec.end(), s2); // not found, obviously, because I can't tell it to compare by value delete s1; delete s2; Is the following the recommended way to do it? template<class T> struct MyEqualsByVal { const T& x_; MyEqualsByVal(const T& x) : x_(x) {} bool operator()(const T& y) const { return *x_ == *y; } }; // ... vec.push_back(s1); Vec::const_iterator found = std::find_if(vec.begin(), vec.end(), MyEqualsByVal<std::string*>(s2)); // OK, will find "foo"

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• delete row from result set in web sql with javascript

  - by Kaijin

  I understand that the result set from web sql isn't quite an array, more of an object? I'm cycling through a result set and to speed things up I'd like to remove a row once it's been found. I've tried "delete" and "splice", the former does nothing and the latter throws an error. Here's a piece of what I'm trying to do, notice the delete on line 18: function selectFromReverse(reverseRay,suggRay){ var reverseString = reverseRay.toString(); db.transaction(function (tx) { tx.executeSql('SELECT votecount, comboid FROM counterCombos WHERE comboid IN ('+reverseString+') AND votecount>0', [], function(tx, results){ processSelectFromReverse(results,suggRay); }); }, function(){onError}); } function processSelectFromReverse(results,suggRay){ var i = suggRay.length; while(i--){ var j = results.rows.length; while(j--){ console.log('searching'); var found = 0; if(suggRay[i].reverse == results.rows.item(j).comboid){ delete results.rows.item(j); console.log('found'); found++; break; } } if(found == 0){ console.log('lost'); } } }

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• check whether mmap'ed address is correct

  - by reddot

  I'm writing a high-loaded daemon that should be run on the FreeBSD 8.0 and on Linux as well. The main purpose of daemon is to pass files that are requested by their identifier. Identifier is converted into local filename/file size via request to db. And then I use sequential mmap() calls to pass file blocks with send(). However sometimes there are mismatch of filesize in db and filesize on filesystem (realsize < size in db). In this situation I've sent all real data blocks and when next data block is mapped -- mmap returns no errors, just usual address (I've checked errno variable also, it's equal to zero after mmap). And when daemon tries to send this block it gets Segmentation Fault. (This behaviour is guarantedly issued on FreeBSD 8.0 amd64) I was using safe check before open to ensure size with stat() call. However real life shows to me that segfault still can be raised in rare situtaions. So, my question is there a way to check whether pointer is accessible before dereferencing it? When I've opened core in gdb, gdb says that given address is out of bound. Probably there is another solution somebody can propose.

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• CSS filters - sometimes working, sometimes not?

  - by a2h

  I'm on the verge of pulling my hair out over this. Here I have a block of perfectly functioning CSS: #admin .block.mode.off { opacity: 0.25; -ms-filter: "progid:DXImageTransform.Microsoft.Alpha(opacity=25)"; filter: progid:DXImageTransform.Microsoft.Alpha(opacity=25); } Meanwhile... Internet Explorer 8 couldn't care less about my filter declarations here: #admin .drop .tabs { margin-bottom: 12px; } #admin .drop .tab { margin-right: 4px; } #admin .drop .tab.off { cursor: pointer; opacity: 0.5; -ms-filter: "progid:DXImageTransform.Microsoft.Alpha(opacity=50)"; filter: progid:DXImageTransform.Microsoft.Alpha(opacity=50); } #admin .drop .tab.off:hover { text-shadow: 0px 0px 4px #fff; } #admin .drop .tab.on { cursor: default; text-shadow: 0px 0px 4px #fff; -ms-filter: "progid:DXImageTransform.Microsoft.Glow(color=#fff, strength=4)"; filter: progid:DXImageTransform.Microsoft.Glow(color=#fff, strength=4); } My document shows in IE8 Standards, and I am assuming the developer tools are a load of tuna, because the functioning block shows up in its CSS tab as: filter: progid:DXImageTransform.Microsoft.Alpha(opacity=25); opacity: 0.25 Does anyone have any ideas?

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• Memory leak when returning object

  - by Yakattak

  I have this memory leak that has been very stubborn for the past week or so. I have a class method I use in a class called "ArchiveManager" that will unarchive a specific .dat file for me, and return an array with it's contents. Here is the method: +(NSMutableArray *)unarchiveCustomObject { NSMutableArray *array = [NSMutableArray arrayWithArray:[NSKeyedUnarchiver unarchiveObjectWithFile:/* Archive Path */]]; return array; } I understand I don't have ownership of it at this point, and I return it. CustomObject *myObject = [[ArchiveManager unarchiveCustomObject] objectAtIndex:0]; Then, later when I unarchive it in a view controller to be used (I don't even create an array of it, nor do I make a pointer to it, I just reference it to get something out of the array returned by unarchiveCustomIbject (objectAtIndex). This is where Instruments is calling a memory leak, yet I don't see how this can leak! Any ideas? Thanks in advance. Edit: CustomObject initWithCoder added: -(id)initWithCoder:(NSCoder *)aDecoder { if (self = [super init]) { self.string1 = [aDecoder decodeObjectForKey:kString1]; self.string2 = [aDecoder decodeObjectForKey:kString2]; self.string3 = [aDecoder decodeObjectForKey:kString3]; UIImage *picture = [[UIImage alloc] initWithData:[aDecoder decodeObjectForKey:kPicture]]; self.picture = picture; self.array = [aDecoder decodeObjectForKey:kArray]; [picture release]; } return self; }

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• Using Partitions for a large MySQL table

  - by user293594

  An update on my attempts to implement a 505,000,000-row table on MySQL on my MacBook Pro: Following the advice given, I have partitioned my table, tr: i UNSIGNED INT NOT NULL, j UNSIGNED INT NOT NULL, A FLOAT(12,8) NOT NULL, nu BIGINT NOT NULL, KEY (nu), key (A) with a range on nu. nu ought to be a real number, but because I only have 6-d.p. accuracy and the maximum value of nu is 30000. I multiplied it by 10^8 made it a BIGINT - I gather one can't use FLOAT or DOUBLE values to PARTITION a MySQL table. Anyway, I have 15 partitions (p0: nu<25,000,000,000, p1: nu<50,000,000,000, etc.). I was thinking that this should speed up a typical to SELECT: SELECT * FROM tr WHERE nu>95000000000 AND nu<100000000000 AND A.>1. to something of the order of the same query on a table consisting of only the data in the relevant partition (<30 secs). But it's taking 30mins+ to return rows for queries within a partition and double that if the query is for rows spanning two (contiguous) partitions. I realise I could just have 15 different tables, and query them separately, but is there a way to do this 'automatically' with partitions? Has anyone got any suggestions?

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• Safe to pass objects to C functions when working in JNI Invocation API?

  - by bubbadoughball

  I am coding up something using the JNI Invocation API. A C program starts up a JVM and makes calls into it. The JNIenv pointer is global to the C file. I have numerous C functions which need to perform the same operation on a given class of jobject. So I wrote helper functions which take a jobject and process it, returning the needed data (a C data type...for example, an int status value). Is it safe to write C helper functions and pass jobjects to them as arguments? i.e. (a simple example - designed to illustrate the question): int getStatusValue(jobject jStatus) { return (*jenv)->CallIntMethod(jenv,jStatus,statusMethod); } int function1() { int status; jobject aObj = (*jenv)->NewObject (jenv, aDefinedClass, aDefinedCtor); jobject j = (*jenv)->CallObjectMethod (jenv, aObj, aDefinedObjGetMethod) status = getStatusValue(j); (*jenv)->DeleteLocalRef(jenv,aObj); (*jenv)->DeleteLocalRef(jenv,j); return status; } Thanks.

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• Linked List pop() function

  - by JKid314159

  Consider the following list: [LinkNode * head -- LinkNode * node1 -- LinkNode * node2] I'm creating a stack of FIFO. I Call pop() which I want to pop node1. LinkNode::LinkNode(int numIn) { this->numIn = numIn; next = null; } . . . int LinkNode::pop() { Link * temp = head->next; head = temp->next; int popped = head->nodeNum; delete temp; Return numOut; Question: 1) head should be a pointer or a LinkNode *? 2) Link * temp is created on the call stack and when pop finishes doesn't temp delete automatically? 3) My major confusion is on what is the value of temp-next? Does this point to node1.next which equals node2? Appreciate your help? My reference is C++ for Java Programmers by Weiss.

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• css problem - 'post link'

  - by csetzkorn

  Hi, I am no css expert so I am wondering whether someone could help. I have several forms to delete an item like this: <form action="/Items/DeleteItem" class="deleteForm" method="post"> Some text <input id="Id" name="Id" value="14014" type="hidden"> <input value="Delete" class="link_button" type="submit"> </form> This should look like this: Some text Delete Here ‘Some text’ describes the item and Delete is a ‘link’ which performs a post request to delete the item (as virtually all browsers only support the post and get requests). I have started to style things (CSS below) but the ‘Delete’ ‘link’ is still slightly offset in relation to ‘Some text’ (at least in firefox). I would appreciate any help with the css. Thanks! .link_button { background-color:white; border:0; color:#034af3; text-decoration:underline; font-size:1em; font-family:inherit; cursor:pointer; float:left; margin:0; padding:0; } .deleteForm { float:right; margin:0; padding:0; } Christian

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• Combining cache methods - memcache/disk based

  - by Industrial

  Hi! Here's the deal. We would have taken the complete static html road to solve performance issues, but since the site will be partially dynamic, this won't work out for us. What we have thought of instead is using memcache + eAccelerator to speed up PHP and take care of caching for the most used data. Here's our two approaches that we have thought of right now: Using memcache on all<< major queries and leaving it alone to do what it does best. Usinc memcache for most commonly retrieved data, and combining with a standard harddrive-stored cache for further usage. The major advantage of only using memcache is of course the performance, but as users increases, the memory usage gets heavy. Combining the two sounds like a more natural approach to us, even though the theoretical compromize in performance. Memcached appears to have some replication features available as well, which may come handy when it's time to increase the nodes. What approach should we use? - Is it stupid to compromize and combine the two methods? Should we insted be focusing on utilizing memcache and instead focusing on upgrading the memory as the load increases with the number of users? Thanks a lot!

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• Zend_Form using subforms getValues() problem

  - by wiseguydigital

  Hi all, I am building a form in Zend Framework 1.9 using subforms as well as Zend_JQuery being enabled on those forms. The form itself is fine and all the error checking etc is working as normal. But the issue I am having is that when I'm trying to retrieve the values in my controller, I'm receiving just the form entry for the last subform e.g. My master form class (abbreviated for speed): Master_Form extends Zend_Form { public function init() { ZendX_JQuery::enableForm($this); $this->setAction('actioninhere') ... ->setAttrib('id', 'mainForm') $sub_one = new Form_One(); $sub_one->setDecorators(... in here I add the jQuery as per the docs); $this->addSubForm($sub_one, 'form-one'); $sub_two = new Form_Two(); $sub_two->setDecorators(... in here I add the jQuery as per the docs); $this->addSubForm($sub_two, 'form-two'); } } So that all works as it should in the display and when I submit without filling in the required values, the correct errors are returned. However, in my controller I have this: class My_Controller extends Zend_Controller_Action { public function createAction() { $request = $this->getRequest(); $form = new Master_Form(); if ($request->isPost()) { if ($form->isValid($request->getPost()) { // This is where I am having the problems print_r($form->getValues()); } } } } When I submit this and it gets past isValid(), the $form-getValues() is only returning the elements from the second subform, not the entire form.

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• ColdFusion 8 Slow Performance

  - by JoeBob

  We have started a new CF8 app and it is running dog slow. A test where we go around ColdFusion (queries within a database utility) show normal speed (80ms). CF8 returns the same query in something like 60 to 80 seconds! I have been looking online and seeing lots of posts about CF8 and performance problems, but don't get any overall sense of a solution; just lots of people trying things and saying that they didn't have the problem with CF7. We are also seeing instability on the server, and some errors relating to garbage collection and the memory heap. We have a number of other applications running on CF8 and they perform adequately...our programmer is not an expert or a guru, he just plugs away. We have isolated this down to a single query that takes forever to return, so it is not a complicated test. Are there any known CF8 problems or obvious tweaks that we should consider trying? If we have to start over and learn a new environment, I will never make deadline. JoeBob

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• RSA_sign and RSACryptoProvider.VerifySignature

  - by Miky D

  I'm trying to get up to speed on how to get some code that uses OpenSSL for cryptography, to play nice with another program that I'm writing in C#, using the Microsoft cryptography providers available in .NET. More to the point, I'm trying to have the C# program verify an RSA message signature generated by the OpenSSL code. The code that generates the signature looks something like this: // Code in C, using the OpenSSL RSA implementation char msgToSign[] = "Hello World"; // the message to be signed char signature[RSA_size(rsa)]; // buffer that will hold signature int slen = 0; // will contain signature size // rsa is an OpenSSL RSA context, that's loaded with the public/private key pair memset(signature, 0, sizeof(signature)); RSA_sign(NID_sha1 , (unsigned char*)msgToSign , strlen(msgToSign) , signature , &slen , rsa); // now signature contains the message signature // and can be verified using the RSA_verify counterpart // .. I would like to verify the signature in C# In C#, I would do the following: import the other side's public key into an RSACryptoServiceProvider object receive the message and it's signature try to verify the signature I've got the first two parts working (I've verified that the public key is loading properly because I managed to send an RSA encrypted text from the C# code to the OpenSSL code in C and successfully have it decrypted) In order to verify the signature in C#, I've tried using the: VerifySignature method of the RSACryptoServiceProvider but that didn't work. And digging around the internet I was only able to find some vague information pointing out that .NET uses a different method for generating the signature than OpenSSL does. So, does anybody know how to accomplish this?

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• Scheme: what are the benefits of letrec?

  - by Ixmatus

  While reading "The Seasoned Schemer" I've begun to learn about letrec. I understand what it does (can be duplicated with a Y-Combinator) but the book is using it in lieu of recurring on the already defined function operating on arguments that remain static. An example of an old function using the defined function recurring on itself (nothing special): (define (substitute new old lat) (cond ((null? l) '()) ((eq? (car l) old) (cons new (substitute new old (cdr l)))) (else (cons (car l) (substitute new old (cdr l)))))) Now for an example of that same function but using letrec: (define (substitute new old lat) (letrec ((replace (lambda (l) (cond ((null? l) '()) ((eq? (car l) old) (cons new (replace (cdr l)))) (else (cons (car l) (replace (cdr l)))))))) (replace lat))) Aside from being slightly longer and more difficult to read I don't know why they are rewriting functions in the book to use letrec. Is there a speed enhancement when recurring over a static variable this way because you don't keep passing it?? Is this standard practice for functions with arguments that remain static but one argument that is reduced (such as recurring down the elements of a list)? Some input from more experienced Schemers/LISPers would help!

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• MSBuild file for deployment process

  - by Lee Englestone

  I could do with some pointers, code examples or references that may help me do the following in an msbuild file to help speed up the deployment process.. This scenario involves getting a developers 'local' version onto a 'development' server.. Increment a developers local Web Applications Assembly version number Publish a developers local Web Application files somewhere .rar the publsihed files or folder into the format v[IncrementedAssemblyNumber].rar Copy the .rar to somewhere Backup (.rar) the existing live website folder (located elsewhere) in the format Pre_v[IncrementedAssemblyNumber].rar Move the backed up .rar to a /Backup folder. Overwrite the development web files with the published local web files Should be simple for all those MSBUILD Gurus out there. Like I said, answers or 'Good and applicable' links would be much appreciated. Also i'm thinking of getting one of the MSbuild books. From what I can tell there are 2, possibly 3 contenders. I am not using TFS. Can anyone recommend a book for beginning MSBUILD? Ideally from people that have read more than one book on the subject. Cheers, -- Lee

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