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  • How can I return an object into PHP userspace from my extension?

    - by John Factorial
    I have a C++ object, Graph, which contains a property named cat of type Category. I'm exposing the Graph object to PHP in an extension I'm writing in C++. As long as the Graph's methods return primitives like boolean or long, I can use the Zend RETURN_*() macros (e.g. RETURN_TRUE(); or RETURN_LONG(123);. But how can I make Graph-getCategory(); return a Category object for the PHP code to manipulate? I'm following the tutorial over at http://devzone.zend.com/article/4486, and here's the Graph code I have so far: #include "php_getgraph.h" zend_object_handlers graph_object_handlers; struct graph_object { zend_object std; Graph *graph; }; zend_class_entry *graph_ce; #define PHP_CLASSNAME "WFGraph" ZEND_BEGIN_ARG_INFO_EX(php_graph_one_arg, 0, 0, 1) ZEND_END_ARG_INFO() ZEND_BEGIN_ARG_INFO_EX(php_graph_two_args, 0, 0, 2) ZEND_END_ARG_INFO() void graph_free_storage(void *object TSRMLS_DC) { graph_object *obj = (graph_object*)object; delete obj-graph; zend_hash_destroy(obj-std.properties); FREE_HASHTABLE(obj-std.properties); efree(obj); } zend_object_value graph_create_handler(zend_class_entry *type TSRMLS_DC) { zval *tmp; zend_object_value retval; graph_object *obj = (graph_object*)emalloc(sizeof(graph_object)); memset(obj, 0, sizeof(graph_object)); obj-std.ce = type; ALLOC_HASHTABLE(obj-std.properties); zend_hash_init(obj-std.properties, 0, NULL, ZVAL_PTR_DTOR, 0); zend_hash_copy(obj-std.properties, &type-default_properties, (copy_ctor_func_t)zval_add_ref, (void*)&tmp, sizeof(zval*)); retval.handle = zend_objects_store_put(obj, NULL, graph_free_storage, NULL TSRMLS_CC); retval.handlers = &graph_object_handlers; return retval; } PHP_METHOD(Graph, __construct) { char *perspectives; int perspectives_len; Graph *graph = NULL; zval *object = getThis(); if(zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s", &perspectives, &perspectives_len) == FAILURE) { RETURN_NULL(); } graph = new Graph(perspectives); graph_object *obj = (graph_object*)zend_object_store_get_object(object TSRMLS_CC); obj-graph = graph; } PHP_METHOD(Graph, hasCategory) { long perspectiveId; Graph *graph; graph_object *obj = (graph_object*)zend_object_store_get_object(getThis() TSRMLS_CC); graph = obj-graph; if (graph == NULL) { RETURN_NULL(); } if(zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "l", &perspectiveId) == FAILURE) { RETURN_NULL(); } RETURN_BOOL(graph-hasCategory(perspectiveId)); } PHP_METHOD(Graph, getCategory) { // what to do here? RETURN_TRUE; } function_entry php_getgraph_functions[] = { PHP_ME(Graph,__construct,NULL,ZEND_ACC_PUBLIC|ZEND_ACC_CTOR) PHP_ME(Graph,hasCategory,php_graph_one_arg,ZEND_ACC_PUBLIC) PHP_ME(Graph,getCategory,php_graph_one_arg,ZEND_ACC_PUBLIC) { NULL, NULL, NULL } }; PHP_MINIT_FUNCTION(getgraph) { zend_class_entry ce; INIT_CLASS_ENTRY(ce, PHP_CLASSNAME, php_getgraph_functions); graph_ce = zend_register_internal_class(&ce TSRMLS_CC); graph_ce-create_object = graph_create_handler; memcpy(&graph_object_handlers, zend_get_std_object_handlers(), sizeof(zend_object_handlers)); graph_object_handlers.clone_obj = NULL; return SUCCESS; } zend_module_entry getgraph_module_entry = { #if ZEND_MODULE_API_NO = 20010901 STANDARD_MODULE_HEADER, #endif PHP_GETGRAPH_EXTNAME, NULL, /* Functions */ PHP_MINIT(getgraph), NULL, /* MSHUTDOWN */ NULL, /* RINIT */ NULL, /* RSHUTDOWN */ NULL, /* MINFO */ #if ZEND_MODULE_API_NO = 20010901 PHP_GETGRAPH_EXTVER, #endif STANDARD_MODULE_PROPERTIES }; #ifdef COMPILE_DL_GETGRAPH extern "C" { ZEND_GET_MODULE(getgraph) } #endif

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  • Very simple shopping cart, remove button

    - by Kynian
    Im writing sales software that will be walking through a set of pages and on certain pages there are items listed to sell and when you click buy it basically just passes a hidden variable to the next page to be set as a session variable, and then when you get to the end it call gets reported to a database. However my employer wanted me to include a shopping cart, and this shopping cart should display the item name, sku, and price of whatever you're buying, as well as a remove button so the person doing the script doesnt need to go back through the entire thing to remove one item. At the moment I have the cart set to display everything, which was fairly simple. but I cant figure out how to get the remove button to work. Here is the code for the shopping cart: $total = 0; //TEST CODE: $_SESSION['itemname-addon'] = "Test addon"; $_SESSION ['price-addon'] = 10.00; $_SESSION ['sku-addon'] = "1234h"; $_SESSION['itemname-addon1'] = "Test addon1"; $_SESSION ['price-addon1'] = 99.90; $_SESSION ['sku-addon1'] = "1111"; $_SESSION['itemname-addon2'] = "Test addon2"; $_SESSION ['price-addon2'] = 19.10; $_SESSION ['sku-addon2'] = "123"; //end test code $items = Array ( "0"=> Array ( "name" => $_SESSION['itemname-mo'], "price" => $_SESSION ['price-mo'], "sku" => $_SESSION ['sku-mo'] ), "1" => Array ( "name" => $_SESSION['itemname-addon'], "price" => $_SESSION ['price-addon'], "sku" => $_SESSION ['sku-addon'] ), "2" => Array ( "name" => $_SESSION['itemname-addon1'], "price" => $_SESSION ['price-addon1'], "sku" => $_SESSION ['sku-addon1'] ), "3" => Array ( "name" => $_SESSION['itemname-addon2'], "price" => $_SESSION ['price-addon2'], "sku" => $_SESSION ['sku-addon2'] ) ); $a_length = count($items); for($x = 0; $x<$a_length; $x++){ $total +=$items[$x]['price']; } $formattedtotal = number_format($total,2,'.',''); for($i = 0; $i < $a_length; $i++){ $name = $items[$i]['name']; $price = $items[$i]['price']; $sku = $items[$i]['sku']; displaycart($name,$price,$sku); } echo "<br /> <b>Sub Total:</b> $$formattedtotal"; function displaycart($name,$price,$sku){ if($name != null || $price != null || $sku != null){ if ($name == "no sale" || $price == "no sale" || $sku == "no sale"){ echo ""; } else{ $formattedprice = number_format($price,2,'.',''); echo "$name: $$formattedprice ($sku)"; echo "<form action=\"\" method=\"post\">"; echo "<button type=\"submit\" />Remove</button><br />"; echo "</form>"; } } } So at this point Im not sure where to go from here for the remove button. Any suggestions would be appreciated.

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  • How can I keep my MVC Views, models, and model binders as clean as possible?

    - by MBonig
    I'm rather new to MVC and as I'm getting into the whole framework more and more I'm finding the modelbinders are becoming tough to maintain. Let me explain... I am writing a basic CRUD-over-database app. My domain models are going to be very rich. In an attempt to keep my controllers as thin as possible I've set it up so that on Create/Edit commands the parameter for the action is a richly populated instance of my domain model. To do this I've implemented a custom model binder. As a result, though, this custom model binder is very specific to the view and the model. I've decided to just override the DefaultModelBinder that ships with MVC 2. In the case where the field being bound to my model is just a textbox (or something as simple), I just delegate to the base method. However, when I'm working with a dropdown or something more complex (the UI dictates that date and time are separate data entry fields but for the model it is one Property), I have to perform some checks and some manual data munging. The end result of this is that I have some pretty tight ties between the View and Binder. I'm architecturally fine with this but from a code maintenance standpoint, it's a nightmare. For example, my model I'm binding here is of type Log (this is the object I will get as a parameter on my Action). The "ServiceStateTime" is a property on Log. The form values of "log.ServiceStartDate" and "log.ServiceStartTime" are totally arbitrary and come from two textboxes on the form (Html.TextBox("log.ServiceStartTime",...)) protected override object GetPropertyValue(ControllerContext controllerContext, ModelBindingContext bindingContext, PropertyDescriptor propertyDescriptor, IModelBinder propertyBinder) { if (propertyDescriptor.Name == "ServiceStartTime") { string date = bindingContext.ValueProvider.GetValue("log.ServiceStartDate").ConvertTo(typeof (string)) as string; string time = bindingContext.ValueProvider.GetValue("log.ServiceStartTime").ConvertTo(typeof (string)) as string; DateTime dateTime = DateTime.Parse(date + " " + time); return dateTime; } if (propertyDescriptor.Name == "ServiceEndTime") { string date = bindingContext.ValueProvider.GetValue("log.ServiceEndDate").ConvertTo(typeof(string)) as string; string time = bindingContext.ValueProvider.GetValue("log.ServiceEndTime").ConvertTo(typeof(string)) as string; DateTime dateTime = DateTime.Parse(date + " " + time); return dateTime; } The Log.ServiceEndTime is a similar field. This doesn't feel very DRY to me. First, if I refactor the ServiceStartTime or ServiceEndTime into different field names, the text strings may get missed (although my refactoring tool of choice, R#, is pretty good at this sort of thing, it wouldn't cause a build-time failure and would only get caught by manual testing). Second, if I decided to arbitrarily change the descriptors "log.ServiceStartDate" and "log.ServiceStartTime", I would run into the same problem. To me, runtime silent errors are the worst kind of error out there. So, I see a couple of options to help here and would love to get some input from people who have come across some of these issues: Refactor any text strings in common between the view and model binders out into const strings attached to the ViewModel object I pass from controller to the aspx/ascx view. This pollutes the ViewModel object, though. Provide unit tests around all of the interactions. I'm a big proponent of unit tests and haven't started fleshing this option out but I've got a gut feeling that it won't save me from foot-shootings. If it matters, the Log and other entities in the system are persisted to the database using Fluent NHibernate. I really want to keep my controllers as thin as possible. So, any suggestions here are greatly welcomed! Thanks

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  • Const-correctness semantics in C++

    - by thirtythreeforty
    For fun and profit™, I'm writing a trie class in C++ (using the C++11 standard.) My trie<T> has an iterator, trie<T>::iterator. (They're all actually functionally const_iterators, because you cannot modify a trie's value_type.) The iterator's class declaration looks partially like this: template<typename T> class trie<T>::iterator : public std::iterator<std::bidirectional_iterator_tag, T> { friend class trie<T>; struct state { state(const trie<T>* const node, const typename std::vector<std::pair<typename T::value_type, std::unique_ptr<trie<T>>>>::const_iterator& node_map_it ) : node{node}, node_map_it{node_map_it} {} // This pointer is to const data: const trie<T>* node; typename std::vector<std::pair<typename T::value_type, std::unique_ptr<trie<T>>>>::const_iterator node_map_it; }; public: typedef const T value_type; iterator() =default; iterator(const trie<T>* node) { parents.emplace(node, node->children.cbegin()); // ... } // ... private: std::stack<state> parents; // ... }; Notice that the node pointer is declared const. This is because (in my mind) the iterator should not be modifying the node that it points to; it is just an iterator. Now, elsewhere in my main trie<T> class, I have an erase function that has a common STL signature--it takes an iterator to data to erase (and returns an iterator to the next object). template<typename T> typename trie<T>::iterator trie<T>::erase(const_iterator it) { // ... // Cannot modify a const object! it.parents.top().node->is_leaf = false; // ... } The compiler complains because the node pointer is read-only! The erase function definitely should modify the trie that the iterator points to, even though the iterator shouldn't. So, I have two questions: Should iterator's constructors be public? trie<T> has the necessary begin() and end() members, and of course trie<T>::iterator and trie<T> are mutual friends, but I don't know what the convention is. Making them private would solve a lot of the angst I'm having about removing the const "promise" from the iterator's constructor. What are the correct const semantics/conventions regarding the iterator and its node pointer here? Nobody has ever explained this to me, and I can't find any tutorials or articles on the Web. This is probably the more important question, but it does require a good deal of planning and proper implementation. I suppose it could be circumvented by just implementing 1, but it's the principle of the thing!

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  • Are all <canvas> tag dimensions in pixels?

    - by Simon Omega
    Are all tag dimensions in pixels? I am asking because I understood them to be. But my math is broken or I am just not grasping something here. I have been doing python mostly and just jumped back into Java Scripting. If I am just doing something stupid let me know. For a game I am writing, I wanted to have a blocky gradient. I have the following: HTML <canvas id="heir"></canvas> CSS @media screen { body { font-size: 12pt } /* Game Rendering Space */ canvas { width: 640px; height: 480px; border-style: solid; border-width: 1px; } } JavaScript (Shortened) function testDraw ( thecontext ) { var myblue = 255; thecontext.save(); // Save All Settings (Before this Function was called) for (var i = 0; i < 480; i = i + 10 ) { if (myblue.toString(16).length == 1) { thecontext.fillStyle = "#00000" + myblue.toString(16); } else { thecontext.fillStyle = "#0000" + myblue.toString(16); } thecontext.fillRect(0, i, 640, 10); myblue = myblue - 2; }; thecontext.restore(); // Restore Settings to Save Point (Removing Styles, etc...) } function main () { var targetcontext = document.getElementById(“main”).getContext("2d"); testDraw(targetcontext); } To me this should produce a series of 640w by 10h pixel bars. In Google Chrome and Fire Fox I get 15 bars. To me that means ( 480 / 15 ) is 32 pixel high bars. So I change the code to: function testDraw ( thecontext ) { var myblue = 255; thecontext.save(); // Save All Settings (Before this Function was called) for (var i = 0; i < 16; i++ ) { if (myblue.toString(16).length == 1) { thecontext.fillStyle = "#00000" + myblue.toString(16); } else { thecontext.fillStyle = "#0000" + myblue.toString(16); } thecontext.fillRect(0, (i * 10), 640, 10); myblue = myblue - 10; }; thecontext.restore(); // Restore Settings to Save Point (Removing Styles, etc...) } And get a true 32 pixel height result for comparison. Other than the fact that the first code snippet has shades of blue rendering in non-visible portions of the they are measuring 32 pixels. Now back to the Original Java Code... If I inspect the tag in Chrome it reports 640 x 480. If I inspect it in Fire Fox it reports 640 x 480. BUT! Fire Fox exports the original code to png at 300 x 150 (which is 15 rows of 10). Is it some how being resized to 640 x 480 by the CSS instead of being set to a true 640 x 480? Why, how, what? O_o I confused...

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  • merge 2 php arrays which aren't of the same length by value

    - by Iain Urquhart
    Excuse me if this has indeed been asked before, I couldn't see anything that fitted my needs out of the dozens of similar titled posts out there ;) I'm trying to merge 2 php arrays which aren't of the same length, and merge them on a value that exists from identical key = values within both arrays. My first query produces an array from a nested set: array ( 1 => array ( 'node_id' => 1, 'lft' => 1, 'rgt' => 4, 'moved' => 0, 'label' => 'Home', 'entry_id' => 1, 'template_path' => '', 'custom_url' => '/', 'extra' => '', 'childs' => 1, 'level' => 0, 'lower' => 0, 'upper' => 0 ), 2 => array ( 'node_id' => 2, 'lft' => 2, 'rgt' => 3, 'moved' => 0, 'label' => 'Home', 'entry_id' => NULL, 'template_path' => '', 'custom_url' => 'http://google.com/', 'extra' => '', 'childs' => 0, 'level' => 1, 'lower' => 0, 'upper' => 0 ) ); My second array returns some additional key/values I'd like to insert to the above array: array ( 'entry_id' => 1, 'entry_title' => 'This is my title', ); I want to merge both of the arrays inserting the additional information into those that match on the key 'entry_id', as well as keeping the sub arrays which don't match. So, by combining the two arrays, I'd end up with array ( 1 => array ( 'node_id' => 1, 'lft' => 1, 'rgt' => 4, 'moved' => 0, 'label' => 'Home', 'entry_id' => 1, 'template_path' => '', 'custom_url' => '/', 'extra' => '', 'childs' => 1, 'level' => 0, 'lower' => 0, 'upper' => 0, 'entry_title' => 'This is my title' ), 2 => array ( 'node_id' => 2, 'lft' => 2, 'rgt' => 3, 'moved' => 0, 'label' => 'Home', 'entry_id' => NULL, 'template_path' => '', 'custom_url' => 'http://google.com/', 'extra' => '', 'childs' => 0, 'level' => 1, 'lower' => 0, 'upper' => 0, 'entry_title' => NULL ) ); Actually, writing this out makes me think I should do it via sql... Any help/advice greatly appreciated...

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  • TCP client in C and server in Java

    - by faldren
    I would like to communicate with 2 applications : a client in C which send a message to the server in TCP and the server in Java which receive it and send an acknowledgement. Here is the client (the code is a thread) : static void *tcp_client(void *p_data) { if (p_data != NULL) { char const *message = p_data; int sockfd, n; struct sockaddr_in serv_addr; struct hostent *server; char buffer[256]; sockfd = socket(AF_INET, SOCK_STREAM, 0); if (sockfd < 0) { error("ERROR opening socket"); } server = gethostbyname(ALARM_PC_IP); if (server == NULL) { fprintf(stderr,"ERROR, no such host\n"); exit(0); } bzero((char *) &serv_addr, sizeof(serv_addr)); serv_addr.sin_family = AF_INET; bcopy((char *)server->h_addr, (char *)&serv_addr.sin_addr.s_addr, server->h_length); serv_addr.sin_port = htons(TCP_PORT); if (connect(sockfd,(struct sockaddr *) &serv_addr,sizeof(serv_addr)) < 0) { error("ERROR connecting"); } n = write(sockfd,message,strlen(message)); if (n < 0) { error("ERROR writing to socket"); } bzero(buffer,256); n = read(sockfd,buffer,255); if (n < 0) { error("ERROR reading from socket"); } printf("Message from the server : %s\n",buffer); close(sockfd); } return 0; } And the java server : try { int port = 9015; ServerSocket server=new ServerSocket(port); System.out.println("Server binded at "+((server.getInetAddress()).getLocalHost()).getHostAddress()+":"+port); System.out.println("Run the Client"); while (true) { Socket socket=server.accept(); BufferedReader in= new BufferedReader(new InputStreamReader(socket.getInputStream())); System.out.println(in.readLine()); PrintStream out=new PrintStream(socket.getOutputStream()); out.print("Welcome by server\n"); out.flush(); out.close(); in.close(); System.out.println("finished"); } } catch(Exception err) { System.err.println("* err"+err); } With n = read(sockfd,buffer,255); the client is waiting a response and for the server, the message is never ended so it doesn't send a response with PrintStream. If I remove these lines : bzero(buffer,256); n = read(sockfd,buffer,255); if (n < 0) { error("ERROR reading from socket"); } printf("Message from the server : %s\n",buffer); The server knows that the message is finished but the client can't receive the response. How solve that ? Thank you

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  • Merge XML files with configurable rules (context: Maven POMs, Java)

    - by Patrick Bergner
    Hi, I'm currently writing some kind of a Maven POM preprocessor that assembles a POM for a project from multiple input files (basically a template and a module specific file). The files are hierarchically ordered (template = most general, module specific = least general). The problem is now to merge these files into a single POM file. Long story short or if you're not familiar with Maven: a POM looks like this (shortened): <project> <modelVersion>4.0.0</modelVersion> <dependencies> <dependency> <groupId>org.apache.maven</groupId> <artifactId>maven-core</artifactId> </dependency> </dependencies> </project> Basically the merger shall replace all values of the more general file with the values of the more specific file (i.e. singletons, e.g. the <modelVersion> above) but there are certain elements where the merger shall add the more certain element to a parent (i.e. collections, e.g. <dependency> elements shall always be added to the <dependencies> element and no <dependency> element shall be replaced by another). A more detailed example with definition of desired output: File A: <project> <modelVersion>A</modelVersion> <dependencies> <dependency> <groupId>groupIdA</groupId> <artifactId>artifactIdA</artifactId> </dependency> </dependencies> </project> File B: <project> <modelVersion>B</modelVersion> <dependencies> <dependency> <groupId>groupIdB</groupId> <artifactId>artifactIdB</artifactId> </dependency> </dependencies> </project> Desired output: <project> <modelVersion>B</modelVersion> <dependencies> <dependency> <groupId>groupIdA</groupId> <artifactId>artifactIdA</artifactId> </dependency> <dependency> <groupId>groupIdB</groupId> <artifactId>artifactIdB</artifactId> </dependency> </dependencies> </project> The set of collection type elements are known and should be configurable (preferably via a set of XPath expressions). A Java based solution is appreciated. What looked most promising so far was the tool mentioned here but the MERGE action produces something like <dependency> <groupId>groupIdAgroupIdB</groupId> <artifactId>artifactIdAartifactIdB</artifactId> </dependency> when merging, which is not what I need. Any ideas? Thanks for your help!

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  • java ioexception error=24 too many files open

    - by MattS
    I'm writing a genetic algorithm that needs to read/write lots of files. The fitness test for the GA is invoking a program called gradif, which takes a file as input and produces a file as output. Everything is working except when I make the population size and/or the total number of generations of the genetic algorithm too large. Then, after so many generations, I start getting this: java.io.FileNotFoundException: testfiles/GradifOut29 (Too many open files). (I get it repeatedly for many different files, the index 29 was just the one that came up first last time I ran it). It's strange because I'm not getting the error after the first or second generation, but after a significant amount of generations, which would suggest that each generation opens up more files that it doesn't close. But as far as I can tell I'm closing all of the files. The way the code is set up is the main() function is in the Population class, and the Population class contains an array of Individuals. Here's my code: Initial creation of input files (they're random access so that I could reuse the same file across multiple generations) files = new RandomAccessFile[popSize]; for(int i=0; i<popSize; i++){ files[i] = new RandomAccessFile("testfiles/GradifIn"+i, "rw"); } At the end of the entire program: for(int i=0; i<individuals.length; i++){ files[i].close(); } Inside the Individual's fitness test: FileInputStream fin = new FileInputStream("testfiles/GradifIn"+index); FileOutputStream fout = new FileOutputStream("testfiles/GradifOut"+index); Process process = Runtime.getRuntime().exec ("./gradif"); OutputStream stdin = process.getOutputStream(); InputStream stdout = process.getInputStream(); Then, later.... try{ fin.close(); fout.close(); stdin.close(); stdout.close(); process.getErrorStream().close(); }catch (IOException ioe){ ioe.printStackTrace(); } Then, afterwards, I append an 'END' to the files to make parsing them easier. FileWriter writer = new FileWriter("testfiles/GradifOut"+index, true); writer.write("END"); try{ writer.close(); }catch(IOException ioe){ ioe.printStackTrace(); } My redirection of stdin and stdout for gradif are from this answer. I tried using the try{close()}catch{} syntax to see if there was a problem with closing any of the files (there wasn't), and I got that from this answer. It should also be noted that the Individuals' fitness tests run concurrently. UPDATE: I've actually been able to narrow it down to the exec() call. In my most recent run, I first ran in to trouble at generation 733 (with a population size of 100). Why are the earlier generations fine? I don't understand why, if there's no leaking, the algorithm should be able to pass earlier generations but fail on later generations. And if there is leaking, then where is it coming from? UPDATE2: In trying to figure out what's going on here, I would like to be able to see (preferably in real-time) how many files the JVM has open at any given point. Is there an easy way to do that?

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  • how to get rid off garbage in array of chars?

    - by fang_dejavu
    hi, I'm writing a C program but I keep having problems with my array of chars. I keep getting garbage when I print it using prinf. here is an example of what I get when I print it: char at t.symbol is Aôÿ¿ char at tabl[0].symbol is A char at tabl[1].symbol is a char at tabl[2].symbol is a char at tabl[3].symbol is d char at tabl[4].symbol is e char at tabl[5].symbol is f char at tabl[6].symbol is g char at tabl[7].symbol is h char at tabl[8].symbol is i char at tabl[9].symbol is x char at t[0].symbol is a0AÃ char at t[1].symbol is b)@Ã4 char at t[2].symbol is ckU* char at t[3].symbol is Aôÿ¿ char at t[4].symbol is gØ could someone tell me how to get rid off the garbage in the array of chars? here is my code #define MAX 100 #ifndef SYMBSIZE #define SYMBSIZE 1 #endif typedef struct tableme { char symbol[SYMBSIZE]; int value; int casenmbr; int otherinfo; }tabletype; int main(int argc, char **argv) { tabletype t[MAX]; t[3].symbol[0] = 'A'; t[0].value=1; t[0].casenmbr = 7; t[0].otherinfo = 682; tabletype tabl[MAX]; tabl[0].value = 1; tabl[0].symbol[0] = 'A'; tabl[1].value = 11; tabl[1].symbol[0]= 'a'; tabl[2].value = 12; tabl[2].symbol[0] = 'a'; tabl[3].value = 13; tabl[3].symbol[0] = 'd'; tabl[4].value = 14; tabl[4].symbol[0] = 'e'; tabl[5].value = 15; tabl[5].symbol[0] = 'f'; tabl[6].value = 16; tabl[6].symbol[0] = 'g'; tabl[7].value = 17; tabl[7].symbol[0] = 'h'; tabl[8].symbol[0] = 'i'; tabl[9].symbol[0] = 'x'; t[1].symbol[0] = 'b'; t[0].symbol[0]= 'a'; t[2].symbol[0]= 'c'; t[4].symbol[0]= 'g'; printf("char at t.symbol is %s \n", t[3].symbol); for( x=0;x<10;x++) { printf("char at tabl[%d].symbol is %s \n",x, tabl[x].symbol); } int j; for(j = 0; j<5;j++) { printf("char at t[%d].symbol is %s \n",j, t[j].symbol); } return 0; }

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  • C++ Serial Port Question

    - by Pfeffer
    Problem: I have a hand held device that scans those graphic color barcodes on all packaging. There is a track device that I can use that will slide the device automatically. This track device functions by taking ascii code through a serial port. I need to get this thing to work in FileMaker on a Mac. So no terminal programs, etc... What I've got so far: I bought a Keyspan USB/Serial adapter. Using a program called ZTerm I was successful in sending commands to the device. Example: "C,7^M^J" I was also able to do the same thing in Terminal using this command: screen /dev/tty.KeySerial1 57600 and then type in the same command above(but when I typed in I just hit Control-M and Control-J for the carriage return and line feed) Now I'm writing a plug-in for FileMaker(in C++ of course). I want to get what I did above happen in C++ so when I install that plug-in in FileMaker I can just call one of those functions and have the whole process take place right there. I'm able to connect to the device, but I can't talk to it. It is not responding to anything. I've tried connecting to the device(successfully) using these: FILE *comport; if ((comport = fopen("/dev/tty.KeySerial1", "w")) == NULL){...} and int fd; fd = open("/dev/tty.KeySerial1", O_RDWR | O_NOCTTY | O_NDELAY); This is what I've tried so far in way of talking to the device: fputs ("C,7^M^J",comport); or fprintf(comport,"C,7^M^J"); or char buffer[] = { 'C' , ',' , '7' , '^' , 'M' , '^' , 'J' }; fwrite (buffer , 1 , sizeof(buffer) , comport ); or fwrite('C,7^M^J', 1, 1, comport); Questions: When I connected to the device from Terminal and using ZTerm, I was able to set my baud rate of 57600. I think that may be why it isn't responding here. But I don't know how to do it here.... Does any one know how to do that? I tried this, but it didn't work: comport->BaudRate = 57600; There are a lot of class solutions out there but they all call these include files like termios.h and stdio.h. I don't have these and, for whatever reason, I can't find them to download. I've downloaded a few examples but there are like 20 files in them and they're all calling other files I can't find(like the ones listed above). Do I need to find these and if so where? I just don't know enough about C++ Is there a website where I can download libraries?? Another solution might be to put those terminal commands in C++. Is there a way to do that? So this has been driving me crazy. I'm not a C++ guy, I only know basic programming concepts. Is anyone out there a C++ expert? I ideally I'd like this to just work using functions I already have, like those fwrite, fputs stuff. Thanks!

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  • How to find an element in an array in C

    - by gkaykck
    I am trying to find the location of an element in the array. I have tried to use this code i generated for(i=0;i<10;i++) { if (strcmp(temp[0],varptr[i])==0) j=i; } varptr is a pointer which points to array var[11][10] and it is by the definition *varptr[11][10]. I have assigned strings to var[i] and i want to get the "i" number of my element NOT THE ADRESS. Thanks for any comment. EDit: temp is also a pointer which points to the string that i want to check. Also i am using the 2D array for keeping variable names and their address. So yes i want to keep it inside a 2D array. The question is this code is not working at all, it does not assigns i to j, so i wonder where is the problem with this idea? writing a "break" does not change if the code works or not, it just optimizes the code a little. Full Code: #include <stdio.h> #include <string.h> #include <ctype.h> double atof(char*); int main(void) { char in[100], *temp[10],var[11][10],*varptr[11][10]; int i,j, n = 0,fullval=0; double val[11]; strcpy(var[11], "ans"); for(i=0;i<11;i++) { for(j=0;j<10;j++) varptr[i][j]=&var[i][j]; } START: printf("Enter the expression: "); fflush(stdout); for(i=0;i<10;i++) temp[i]=NULL; if (fgets(in, sizeof in, stdin) != NULL) { temp[0] = strtok(in, " "); if (temp[0] != NULL) { for (n = 1; n < 10 && (temp[n] = strtok(NULL," ")) != NULL; n++) ; } if (*temp[0]=="quit") { goto FINISH;} if (isdigit(*temp[0])) { if (*temp[1]=='+') val[0] = atof(temp[0])+atof(temp[2]); else if (*temp[1]=='-') val[0] = atof(temp[0])-atof(temp[2]); else if (*temp[1]=='*') val[0] = atof(temp[0])*atof(temp[2]); else if (*temp[1]=='/') val[0] = atof(temp[0])/atof(temp[2]); printf("%s = %f\n",var[11],val[0]); goto START; } else if (temp[1]==NULL) //asking the value of a variable { for(i=0;i<10;i++) { if (strcmp(temp[0],varptr[i])==0) j=i; } printf("%s = %d\n",var[j],val[j]); goto START; } if (*temp[1]==61) { strcpy(var[fullval], temp[0]); if ((temp[3])!=NULL) { } val[fullval]=atof(temp[2]); printf("%s = %f\n",var[fullval],val[fullval]); fullval++; goto START; } if (*temp[1]!=61) { } } getch(); FINISH: return 0; }

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  • android ftp upload has stopped error

    - by Goxel Arp
    class Asenkron extends AsyncTask<String,Integer,Long> { @Override protected Long doInBackground(String... aurl) { FTPClient con=null; try ` { con = new FTPClient(); con.connect(aurl[0]); if (con.login(aurl[1], aurl[2])) { con.enterLocalPassiveMode(); // important! con.setFileType(http://FTP.BINARY_FILE_TYPE); FileInputStream in = new FileInputStream(new File(aurl[3])); boolean result = con.storeFile(aurl[3], in); in.close(); con.logout(); con.disconnect(); } } catch (Exception e) { Toast.makeText(getApplicationContext(), e.toString(), Toast.LENGTH_LONG).show(); } return null; } protected void onPostExecute(String result) {} } I AM USING THIS CLASS LIKE BELOW.THERE IS BUTTON AND WHENEVER I CLICK THE BUTTON IT SHOULD START FTP UPLOAD PROCESS IN BACKGROUND BUT I GET "PROGRAM HAS STOPPED UNFORTUNATELY" ERROR. Assume that The ftp address and username password pathfile sections are true and I get the internet and network permissions already by the way ... button1.setOnClickListener(new OnClickListener() { public void onClick(View arg0) { new Asenkron().execute("ftpaddress","username","pass","pathfileon telephone"); } }); And here is the logcat for you to analyse the potential error and help me ... 10-13 13:01:25.591: I/dalvikvm(633): threadid=3: reacting to signal 3 10-13 13:01:25.711: I/dalvikvm(633): Wrote stack traces to '/data/anr/traces.txt' 10-13 13:01:25.921: D/gralloc_goldfish(633): Emulator without GPU emulation detected. 10-13 13:01:31.441: W/dalvikvm(633): threadid=11: thread exiting with uncaught exception (group=0x409c01f8) 10-13 13:01:31.461: E/AndroidRuntime(633): FATAL EXCEPTION: AsyncTask #1 10-13 13:01:31.461: E/AndroidRuntime(633): java.lang.RuntimeException: An error occured while executing doInBackground() 10-13 13:01:31.461: E/AndroidRuntime(633): at android.os.AsyncTask$3.done(AsyncTask.java:278) 10-13 13:01:31.461: E/AndroidRuntime(633): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273) 10-13 13:01:31.461: E/AndroidRuntime(633): at java.util.concurrent.FutureTask.setException(FutureTask.java:124) 10-13 13:01:31.461: E/AndroidRuntime(633): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307) 10-13 13:01:31.461: E/AndroidRuntime(633): at java.util.concurrent.FutureTask.run(FutureTask.java:137) 10-13 13:01:31.461: E/AndroidRuntime(633): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:208) 10-13 13:01:31.461: E/AndroidRuntime(633): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076) 10-13 13:01:31.461: E/AndroidRuntime(633): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569) 10-13 13:01:31.461: E/AndroidRuntime(633): at java.lang.Thread.run(Thread.java:856) 10-13 13:01:31.461: E/AndroidRuntime(633): Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare() 10-13 13:01:31.461: E/AndroidRuntime(633): at android.os.Handler.<init>(Handler.java:121) 10-13 13:01:31.461: E/AndroidRuntime(633): at android.widget.Toast$TN.<init>(Toast.java:317) 10-13 13:01:31.461: E/AndroidRuntime(633): at android.widget.Toast.<init>(Toast.java:91) 10-13 13:01:31.461: E/AndroidRuntime(633): at android.widget.Toast.makeText(Toast.java:233) 10-13 13:01:31.461: E/AndroidRuntime(633): at com.example.ftpodak.ODAK$Asenkron.doInBackground(ODAK.java:74) 10-13 13:01:31.461: E/AndroidRuntime(633): at com.example.ftpodak.ODAK$Asenkron.doInBackground(ODAK.java:1) 10-13 13:01:31.461: E/AndroidRuntime(633): at android.os.AsyncTask$2.call(AsyncTask.java:264) 10-13 13:01:31.461: E/AndroidRuntime(633): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305) 10-13 13:01:31.461: E/AndroidRuntime(633): ... 5 more By the way I changed the relevant code like that ; instead of catch (Exception e) { Toast.makeText(getApplicationContext(), e.toString(), Toast.LENGTH_LONG).show(); } I replaced with this code catch (Exception e) { HATA=e.toString(); } And I added the code to button textview1.setText(HATA); So I can see the error on the textview and it is writing that "Android java.net.UnknownHostException: Host is unresolved" But i know that the ftp server is correct and I check the ftp server from the AndFTP application. With the same address login and pass information ftp server is working.So the problem is in my code I think.Any help will be too much appreciated.Anyone who can help me I can give teamviewer to analyse what is the problem ...

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  • Path to background in servlet

    - by kapil chhattani
    //the below line is the element of my HTML form which renders the image sent by the servlet written further below. <img style="margin-left:91px; margin-top:-6px;" class="image" src="http://www.abcd.com/captchaServlet"> I generate a captcha code using the following code in java. public class captchaServlet extends HttpServlet { protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { int width = 150; int height = 50; int charsToPrint = 6; String elegibleChars = "ABCDEFGHJKLMPQRSTUVWXYabcdefhjkmnpqrstuvwxy1234567890"; char[] chars = elegibleChars.toCharArray(); StringBuffer finalString = new StringBuffer(); for ( int i = 0; i < charsToPrint; i++ ) { double randomValue = Math.random(); int randomIndex = (int) Math.round(randomValue * (chars.length - 1)); char characterToShow = chars[randomIndex]; finalString.append(characterToShow); } System.out.println(finalString); BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); Graphics2D g2d = bufferedImage.createGraphics(); Font font = new Font("Georgia", Font.BOLD, 18); g2d.setFont(font); RenderingHints rh = new RenderingHints( RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); rh.put(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY); g2d.setRenderingHints(rh); GradientPaint gp = new GradientPaint(0, 0, Color.BLUE, 0, height/2, Color.black, true); g2d.setPaint(gp); g2d.fillRect(0, 0, width, height); g2d.setColor(new Color(255, 255, 0)); Random r = new Random(); int index = Math.abs(r.nextInt()) % 5; char[] data=new String(finalString).toCharArray(); String captcha = String.copyValueOf(data); int x = 0; int y = 0; for (int i=0; i<data.length; i++) { x += 10 + (Math.abs(r.nextInt()) % 15); y = 20 + Math.abs(r.nextInt()) % 20; g2d.drawChars(data, i, 1, x, y); } g2d.dispose(); response.setContentType("image/png"); OutputStream os = response.getOutputStream(); ImageIO.write(bufferedImage, "png", os); os.close(); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { processRequest(request, response); } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { processRequest(request, response); } } But in the above code background is also generated using the setPaint menthod I am guessing. I want the background to be some image from my local machine whoz URL i should be able to mention like URL url=this.getClass().getResource("Desktop/images.jpg"); BufferedImage bufferedImage = ImageIO.read(url); I am just writing the above two lines for making the reader understand better what the issue is. Dont want to use the exact same commands. All I want is the the background of the captcha code generated should be an image of my choice.

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  • "assignment makes integer from pointer without a cast " warning in c

    - by mekasperasky
    #include<stdio.h> /* this is a lexer which recognizes constants , variables ,symbols, identifiers , functions , comments and also header files . It stores the lexemes in 3 different files . One file contains all the headers and the comments . Another file will contain all the variables , another will contain all the symbols. */ int main() { int i=0,j; char a,b[20],c[30]; FILE *fp1,*fp2; c[0]='"if"; c[1]="then"; c[2]="else"; c[3]="switch"; c[4]="printf"; c[5]="scanf"; c[6]="NULL"; c[7]="int"; c[8]="char"; c[9]="float"; c[10]="long"; c[11]="double"; c[12]="char"; c[13]="const"; c[14]="continue"; c[15]="break"; c[16]="for"; c[17]="size of"; c[18]="register"; c[19]="short"; c[20]="auto"; c[21]="while"; c[22]="do"; c[23]="case"; fp1=fopen("source.txt","r"); //the source file is opened in read only mode which will passed through the lexer fp2=fopen("lext.txt","w"); //now lets remove all the white spaces and store the rest of the words in a file if(fp1==NULL) { perror("failed to open source.txt"); //return EXIT_FAILURE; } i=0; while(!feof(fp1)) { a=fgetc(fp1); if(a!=' ') { b[i]=a; } else { for (j=0;j<23;j++) { if(c[j]==b) { fprintf(fp2, "%.20s\n", c[j]); continue ; } b[i]='\0'; fprintf(fp2, "%.20s\n", b); i=0; continue; } //else if //{ i=i+1; /*Switch(a) { case EOF :return eof; case '+':sym=sym+1; case '-':sym=sym+1; case '*':sym=sym+1; case '/':sym=sym+1; case '%':sym=sym+1; case ' */ } fclose(fp1); fclose(fp2); return 0; } This is my c code for lexical analysis .. its giving warnings and also not writing anything into the lext file ..

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  • LINQ-like or SQL-like DSL for end-users to run queries to select (not modify) data?

    - by Mark Rushakoff
    For a utility I'm working on, the client would like to be able to generate graphic reports on the data that has been collected. I can already generate a couple canned graphs (using ZedGraph, which is a very nice library); however, the utility would be much more flexible if the graphs were more programmable or configurable by the end-user. TLDR version I want users to be able to use something like SQL to safely extract and select data from a List of objects that I provide and can describe. What free tools or libraries will help me accomplish this? Full version I've given thought to using IronPython, IronRuby, and LuaInterface, but frankly they're all a bit overpowered for what I want to do. My classes are fairly simple, along the lines of: class Person: string Name; int HeightInCm; DateTime BirthDate; Weight[] WeighIns; class Weight: int WeightInKg; DateTime Date; Person Owner; (exact classes have been changed to protect the innocent). To come up with the data for the graph, the user will choose whether it's a bar graph, scatter plot, etc., and then to actually obtain the data, I would like to obtain some kind of List from the user simply entering something SQL-ish along the lines of SELECT Name, AVG(WeighIns) FROM People SELECT WeightInKg, Owner.HeightInCm FROM Weights And as a bonus, it would be nice if you could actually do operations as well: SELECT WeightInKg, (Date - Owner.BirthDate) AS Age FROM Weights The DSL doesn't have to be compliant SQL in any way; it doesn't even have to resemble SQL, but I can't think of a more efficient descriptive language for the task. I'm fine filling in blanks; I don't expect a library to do everything for me. What I would expect to exist (but haven't been able to find in any way, shape, or form) is something like Fluent NHibernate (which I am already using in the project) where I can declare a mapping, something like var personRequest = Request<Person>(); personRequest.Item("Name", (p => p.Name)); personRequest.Item("HeightInCm", (p => p.HeightInCm)); personRequest.Item("HeightInInches", (p => p.HeightInCm * CM_TO_INCHES)); // ... var weightRequest = Request<Weight>(); weightRequest.Item("Owner", (w => w.Owner), personRequest); // Indicate a chain to personRequest // ... var people = Table<Person>("People", GetPeopleFromDatabase()); var weights = Table<Weight>("Weights", GetWeightsFromDatabase()); // ... TryRunQuery(userInputQuery); LINQ is so close to what I want to do, but AFAIK there's no way to sandbox it. I don't want to expose any unnecessary functionality to the end user; meaning I don't want the user to be able to send in and process: from p in people select (p => { System.IO.File.Delete("C:\\something\\important"); return p.Name }) So does anyone know of any free .NET libraries that allow something like what I've described above? Or is there some way to sandbox LINQ? cs-script is close too, but it doesn't seem to offer sandboxing yet either. I'd be hesitant to expose the NHibernate interface either, as the user should have a read-only view of the data at this point in the usage. I'm using C# 3.5, and pure .NET solutions would be preferred. The bottom line is that I'm really trying to avoid writing my own parser for a subset of SQL that would only apply to this single project.

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  • Trying to packetize TCP with non-blocking IO is hard! Am I doing something wrong?

    - by Ricket
    Oh how I wish TCP was packet-based like UDP is! But alas, that's not the case, so I'm trying to implement my own packet layer. Here's the chain of events so far (ignoring writing packets) Oh, and my Packets are very simply structured: two unsigned bytes for length, and then byte[length] data. (I can't imagine if they were any more complex, I'd be up to my ears in if statements!) Server is in an infinite loop, accepting connections and adding them to a list of Connections. PacketGatherer (another thread) uses a Selector to figure out which Connection.SocketChannels are ready for reading. It loops over the results and tells each Connection to read(). Each Connection has a partial IncomingPacket and a list of Packets which have been fully read and are waiting to be processed. On read(): Tell the partial IncomingPacket to read more data. (IncomingPacket.readData below) If it's done reading (IncomingPacket.complete()), make a Packet from it and stick the Packet into the list waiting to be processed and then replace it with a new IncomingPacket. There are a couple problems with this. First, only one packet is being read at a time. If the IncomingPacket needs only one more byte, then only one byte is read this pass. This can of course be fixed with a loop but it starts to get sorta complicated and I wonder if there is a better overall way. Second, the logic in IncomingPacket is a little bit crazy, to be able to read the two bytes for the length and then read the actual data. Here is the code, boiled down for quick & easy reading: int readBytes; // number of total bytes read so far byte length1, length2; // each byte in an unsigned short int (see getLength()) public int getLength() { // will be inaccurate if readBytes < 2 return (int)(length1 << 8 | length2); } public void readData(SocketChannel c) { if (readBytes < 2) { // we don't yet know the length of the actual data ByteBuffer lengthBuffer = ByteBuffer.allocate(2 - readBytes); numBytesRead = c.read(lengthBuffer); if(readBytes == 0) { if(numBytesRead >= 1) length1 = lengthBuffer.get(); if(numBytesRead == 2) length2 = lengthBuffer.get(); } else if(readBytes == 1) { if(numBytesRead == 1) length2 = lengthBuffer.get(); } readBytes += numBytesRead; } if(readBytes >= 2) { // then we know we have the entire length variable // lazily-instantiate data buffers based on getLength() // read into data buffers, increment readBytes // (does not read more than the amount of this packet, so it does not // need to handle overflow into the next packet's data) } } public boolean complete() { return (readBytes > 2 && readBytes == getLength()+2); } Basically I need feedback on my code. Please suggest any improvements. Even overhauling my entire system would be okay, if you have suggestions for how better to implement the whole thing. Book recommendations are welcome too; I love books. I just get the feeling that something isn't quite right.

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  • C++ Simple thread with parameter (no .net)

    - by Marc Vollmer
    I've searched the internet for a while now and found different solutions but then all don't really work or are to complicated for my use. I used C++ until 2 years ago so it might be a bit rusty :D I'm currently writing a program that posts data to an URL. It only posts the data nothing else. For posting the data I use curl, but it blocks the main thread and while the first post is still running there will be a second post that should start. In the end there are about 5-6 post operations running at the same time. Now I want to push the posting with curl into another thread. One thread per post. The thread should get a string parameter with the content what to push. I'm currently stuck on this. Tried the WINAPI for windows but that crashes on reading the parameter. (the second thread is still running in my example while the main thread ended (waiting on system("pause")). It would be nice to have a multi plattform solution, because it will run under windows and linux! Heres my current code: #define CURL_STATICLIB #include <curl/curl.h> #include <curl/easy.h> #include <cstdlib> #include <iostream> #include <stdio.h> #include <stdlib.h> #include <string> #if defined(WIN32) #include <windows.h> #else //#include <pthread.h> #endif using namespace std; void post(string post) { // Function to post it to url CURL *curl; // curl object CURLcode res; // CURLcode object curl = curl_easy_init(); // init curl if(curl) { // is curl init curl_easy_setopt(curl, CURLOPT_URL, "http://10.8.27.101/api.aspx"); // set url string data = "api=" + post; // concat post data strings curl_easy_setopt(curl, CURLOPT_POSTFIELDS, data.c_str()); // post data res = curl_easy_perform(curl); // execute curl_easy_cleanup(curl); // cleanup } else { cerr << "Failed to create curl handle!\n"; } } #if defined(WIN32) DWORD WINAPI thread(LPVOID data) { // WINAPI Thread string pData = *((string*)data); // convert LPVOID to string [THIS FAILES] post(pData); // post it with curl } #else // Linux version #endif void startThread(string data) { // FUnction to start the thread string pData = data; // some Test #if defined(WIN32) CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)thread, &pData, 0, NULL); // Start a Windows thread with winapi #else // Linux version #endif } int main(int argc, char *argv[]) { // The post data to send string postData = "test1234567890"; startThread(postData); // Start the thread system("PAUSE"); // Dont close the console window return EXIT_SUCCESS; } Has anyone a suggestion? Thanks for the help!

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  • Haskell: monadic takeWhile?

    - by Mark Rushakoff
    I have some functions written in C that I call from Haskell. These functions return IO (CInt). Sometimes I want to run all of the functions regardless of what any of them return, and this is easy. For sake of example code, this is the general idea of what's happening currently: Prelude> let f x = print x >> return x Prelude> mapM_ f [0..5] 0 1 2 3 4 5 Prelude> I get my desired side effects, and I don't care about the results. But now I need to stop execution immediately after the first item that doesn't return my desired result. Let's say a return value of 4 or higher requires execution to stop - then what I want to do is this: Prelude> takeWhile (<4) $ mapM f [0..5] Which gives me this error: <interactive:1:22: Couldn't match expected type `[b]' against inferred type `IO a' In the first argument of `mapM', namely `f' In the second argument of `($)', namely `mapM f ([0 .. 5])' In the expression: takeWhile (< 4) $ mapM f ([0 .. 5]) And that makes sense to me - the result is still contained in the IO monad, and I can't just compare two values contained in the IO monad. I know this is precisely the purpose of monads -- chaining results together and discarding operations when a certain condition is met -- but is there an easy way to "wrap up" the IO monad in this case to stop executing the chain upon a condition of my choosing, without writing an instance of MonadPlus? Can I just "unlift" the values from f, for the purposes of the takeWhile? Is this a solution where functors fit? Functors haven't "clicked" with me yet, but I sort of have the impression that this might be a good situation to use them. Update: @sth has the closest answer to what I want - in fact, that's almost exactly what I was going for, but I'd still like to see whether there is a standard solution that isn't explicitly recursive -- this is Haskell, after all! Looking back on how I worded my question, now I can see that I wasn't clear enough about my desired behavior. The f function I used above for an example was merely an example. The real functions are written in C and used exclusively for their side effects. I can't use @Tom's suggestion of mapM_ f (takeWhile (&lt;4) [0..5]) because I have no idea whether any input will really result in success or failure until executed. I don't actually care about the returned list, either -- I just want to call the C functions until either the list is exhausted or the first C function returns a failure code. In C-style pseudocode, my behavior would be: do { result = function_with_side_effects(input_list[index++]); } while (result == success && index < max_index); So again, @sth's answer performs the exact behavior that I want, except that the results may (should?) be discarded. A dropWhileM_ function would be equivalent for my purposes. Why isn't there a function like that or takeWhileM_ in Control.Monad? I see that there was a similar discussion on a mailing list, but it appears that nothing has come of that.

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  • How to define template directives (from an API perspective)?

    - by Ralph
    Preface I'm writing a template language (don't bother trying to talk me out of it), and in it, there are two kinds of user-extensible nodes. TemplateTags and TemplateDirectives. A TemplateTag closely relates to an HTML tag -- it might look something like div(class="green") { "content" } And it'll be rendered as <div class="green">content</div> i.e., it takes a bunch of attributes, plus some content, and spits out some HTML. TemplateDirectives are a little more complicated. They can be things like for loops, ifs, includes, and other such things. They look a lot like a TemplateTag, but they need to be processed differently. For example, @for($i in $items) { div(class="green") { $i } } Would loop over $items and output the content with the variable $i substituted in each time. So.... I'm trying to decide on a way to define these directives now. Template Tags The TemplateTags are pretty easy to write. They look something like this: [TemplateTag] static string div(string content = null, object attrs = null) { return HtmlTag("div", content, attrs); } Where content gets the stuff between the curly braces (pre-rendered if there are variables in it and such), and attrs is either a Dictionary<string,object> of attributes, or an anonymous type used like a dictionary. It just returns the HTML which gets plunked into its place. Simple! You can write tags in basically 1 line. Template Directives The way I've defined them now looks like this: [TemplateDirective] static string @for(string @params, string content) { var tokens = Regex.Split(@params, @"\sin\s").Select(s => s.Trim()).ToArray(); string itemName = tokens[0].Substring(1); string enumName = tokens[1].Substring(1); var enumerable = data[enumName] as IEnumerable; var sb = new StringBuilder(); var template = new Template(content); foreach (var item in enumerable) { var templateVars = new Dictionary<string, object>(data) { { itemName, item } }; sb.Append(template.Render(templateVars)); } return sb.ToString(); } (Working example). Basically, the stuff between the ( and ) is not split into arguments automatically (like the template tags do), and the content isn't pre-rendered either. The reason it isn't pre-rendered is because you might want to add or remove some template variables or something first. In this case, we add the $i variable to the template variables, var templateVars = new Dictionary<string, object>(data) { { itemName, item } }; And then render the content manually, sb.Append(template.Render(templateVars)); Question I'm wondering if this is the best approach to defining custom Template Directives. I want to make it as easy as possible. What if the user doesn't know how to render templates, or doesn't know that he's supposed to? Maybe I should pass in a Template instance pre-filled with the content instead? Or maybe only let him tamper w/ the template variables, and then automatically render the content at the end? OTOH, for things like "if" if the condition fails, then the template wouldn't need to be rendered at all. So there's a lot of flexibility I need to allow in here. Thoughts?

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  • Can someone help me compare using F# over C# in this specific example (IP Address expressions)?

    - by Phobis
    So, I am writing code to parse and IP Address expression and turn it into a regular expression that could be run against and IP Address string and return a boolean response. I wrote the code in C# (OO) and it was 110 lines of code. I am trying to compare the amount of code and the expressiveness of C# to F# (I am a C# programmer and a noob at F#). I don't want to post both the C# and F#, just because I don't want to clutter the post. If needed, I will do so. Anyway, I will give an example. Here is an expression: 192.168.0.250,244-248,108,51,7;127.0.0.1 I would like to take that and turn it into this regular expression: ((192.168.0.(250|244|245|246|247|248|108|51|7))|(127.0.0.1)) Here are some steps I am following: Operations: Break by ";" 192.168.0.250,244-248,108,51,7 127.0.0.1 Break by "." 192 168 0 250,244-248,108,51,7 Break by "," 250 244-248 108 51 7 Break by "-" 244 248 I came up with F# that produces the output. I am trying to forward-pipe through my operations listed above, as I think that would be more expressive. Can anyone make this code better? Teach me something :) open System let createItemArray (group:bool) (y:char) (items:string[]) = [| let indexes = items.Length - 1 let group = indexes > 0 && group if group then yield "(" for i in 0 .. indexes do yield items.[i].ToString() if i < indexes then yield y.ToString() if group then yield ")" |] let breakBy (group:bool) (x:string) (y:char): string[] = x.Split(y) |> createItemArray group y let breakItem (x:string) (y:char): string[] = breakBy false x y let breakGroup (x:string) (y:char): string[] = breakBy true x y let AddressExpression address:string = let builder = new System.Text.StringBuilder "(" breakGroup address ';' |> Array.collect (fun octet -> breakItem octet '.') |> Array.collect (fun options -> breakGroup options ',') |> Array.collect (fun (ranges : string) -> match (breakGroup ranges '-') with | x when x.Length > 3 -> match (Int32.TryParse(x.[1]), Int32.TryParse(x.[3])) with | ((true, a) ,(true, b)) -> [|a .. b|] |> Array.map (int >> string) |> createItemArray false '-' | _ -> [|ranges|] | _ -> [|ranges|] ) |> Array.iter (fun item -> match item with | ";" -> builder.Append ")|(" | "." -> builder.Append "\." | "," | "-" -> builder.Append "|" | _ -> builder.Append item |> ignore ) builder.Append(")").ToString() let address = "192.168.0.250,244-248,108,51,7;127.0.0.1" AddressExpression address

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  • Tool or library for end-users to run queries to select (not modify) data?

    - by Mark Rushakoff
    For a utility I'm working on, the client would like to be able to generate graphic reports on the data that has been collected. I can already generate a couple canned graphs (using ZedGraph, which is a very nice library); however, the utility would be much more flexible if the graphs were more programmable or configurable by the end-user. TLDR version I want users to be able to use something like SQL to safely extract and select data from a List of objects that I provide and can describe. What free tools or libraries will help me accomplish this? Full version I've given thought to using IronPython, IronRuby, and LuaInterface, but frankly they're all a bit overpowered for what I want to do. My classes are fairly simple, along the lines of: class Person: string Name; int HeightInCm; DateTime BirthDate; Weight[] WeighIns; class Weight: int WeightInKg; DateTime Date; Person Owner; (exact classes have been changed to protect the innocent). To come up with the data for the graph, the user will choose whether it's a bar graph, scatter plot, etc., and then to actually obtain the data, I would like to obtain some kind of List from the user simply entering something SQL-ish along the lines of SELECT Name, AVG(WeighIns) FROM People SELECT WeightInKg, Owner.HeightInCm FROM Weights And as a bonus, it would be nice if you could actually do operations as well: SELECT WeightInKg, (Date - Owner.BirthDate) AS Age FROM Weights The DSL doesn't have to be compliant SQL in any way; it doesn't even have to resemble SQL, but I can't think of a more efficient descriptive language for the task. I'm fine filling in blanks; I don't expect a library to do everything for me. What I would expect to exist (but haven't been able to find in any way, shape, or form) is something like Fluent NHibernate (which I am already using in the project) where I can declare a mapping, something like var personRequest = Request<Person>(); personRequest.Item("Name", (p => p.Name)); personRequest.Item("HeightInCm", (p => p.HeightInCm)); personRequest.Item("HeightInInches", (p => p.HeightInCm * CM_TO_INCHES)); // ... var weightRequest = Request<Weight>(); weightRequest.Item("Owner", (w => w.Owner), personRequest); // Indicate a chain to personRequest // ... var people = Table<Person>("People", GetPeopleFromDatabase()); var weights = Table<Weight>("Weights", GetWeightsFromDatabase()); // ... TryRunQuery(userInputQuery); LINQ is so close to what I want to do, but AFAIK there's no way to sandbox it. I don't want to expose any unnecessary functionality to the end user; meaning I don't want the user to be able to send in and process: from p in people select (p => { System.IO.File.Delete("C:\\something\\important"); return p.Name }) So does anyone know of any free .NET libraries that allow something like what I've described above? Or is there some way to sandbox LINQ? cs-script is close too, but it doesn't seem to offer sandboxing yet either. I'd be hesitant to expose the NHibernate interface either, as the user should have a read-only view of the data at this point in the usage. I'm using C# 3.5, and pure .NET solutions would be preferred. The bottom line is that I'm really trying to avoid writing my own parser for a subset of SQL that would only apply to this single project.

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  • Do classes which have a vector has a member have memory issues

    - by user263766
    I am just starting out C++, so sorry if this is a dumb question. I have a class Braid whose members are vectors. I have not written an assignment operator. When I do a lot of assignments to an object of the type Braid, I run into memory issues :- 0 0xb7daff89 in _int_malloc () from /lib/libc.so.6 #1 0xb7db2583 in malloc () from /lib/libc.so.6 #2 0xb7f8ac59 in operator new(unsigned int) () from /usr/lib/libstdc++.so.6 #3 0x0804d05e in __gnu_cxx::new_allocator<int>::allocate (this=0xbf800204, __n=1) at /usr/lib/gcc/i686-pc-linux-gnu/4.4.3/../../../../include/c++/4.4.3/ext/new_allocator.h:89 #4 0x0804cb0e in std::_Vector_base<int, std::allocator<int> >::_M_allocate (this=0xbf800204, __n=1) at /usr/lib/gcc/i686-pc-linux-gnu/4.4.3/../../../../include/c++/4.4.3/bits/stl_vector.h:140 #5 0x0804c086 in _Vector_base (this=0xbf800204, __n=1, __a=...) at /usr/lib/gcc/i686-pc-linux-gnu/4.4.3/../../../../include/c++/4.4.3/bits/stl_vector.h:113 #6 0x0804b4b7 in vector (this=0xbf800204, __x=...) at /usr/lib/gcc/i686-pc-linux-gnu/4.4.3/../../../../include/c++/4.4.3/bits/stl_vector.h:242 #7 0x0804b234 in Braid (this=0xbf800204) at braid.h:13 #8 0x080495ed in Braid::cycleBraid (this=0xbf8001b4) at braid.cpp:191 #9 0x080497c6 in Braid::score (this=0xbf800298, b=...) at braid.cpp:251 #10 0x08049c46 in Braid::evaluateMove (this=0xbf800468, move=1, pos=0, depth=2, b=...) I suspect that these memory issues are because the vectors are getting resized. What I want to know is whether objects of type Braid automatically expand when its members expand? he code I am writing is really long so I will post the section which is causing the problems. Here is the relevant section of the code :- class Braid { private : vector<int> braid; //Stores the braid. int strands; vector < vector<bool> > history; vector < vector<bool> > CM; public : Braid () : strands(0) {} Braid operator * (Braid); Braid* inputBraid(int,vector<int>); int printBraid(); int printBraid(vector<vector<int>::iterator>); vector<int>::size_type size() const; ..... ..... } Here is the function which causes the issue :- int Braid::evaluateMove(int move,int pos,int depth,Braid b) { int netscore = 0; Braid curr(*this); curr = curr.move(move,pos); netscore += curr.score(b); while(depth > 1) { netscore += curr.evaluateMove(1,0,depth,b); netscore += curr.evaluateMove(2,0,depth,b); for(int i = 0; i < braid.size();++i) { netscore += curr.evaluateMove(3,i,depth,b); netscore += curr.evaluateMove(4,i,depth,b); netscore += curr.evaluateMove(5,i,depth,b); curr = curr.cycleBraid(); netscore += curr.evaluateMove(6,0,depth,b); } --depth; } return netscore; }

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  • CakePHP access indirectly related model - beginner's question

    - by user325077
    Hi everyone, I am writing a CakePHP application to log the work I do for various clients, but after trying for days I seem unable to get it to do what I want. I have read most of the book CakePHP's website. and googled for all I'm worth, so I presume I am missing something obvious! Every 'log item' belongs to a 'sub-project, which in turn belongs to a 'project', which in turn belongs to a 'sub-client' which finally belongs to a client. These are the 5 MySQL tables I am using: mysql> DESCRIBE log_items; +-----------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-----------------+--------------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | date | date | NO | | NULL | | | time | time | NO | | NULL | | | time_spent | int(11) | NO | | NULL | | | sub_projects_id | int(11) | NO | MUL | NULL | | | title | varchar(100) | NO | | NULL | | | description | text | YES | | NULL | | | created | datetime | YES | | NULL | | | modified | datetime | YES | | NULL | | +-----------------+--------------+------+-----+---------+----------------+ mysql> DESCRIBE sub_projects; +-------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-------------+--------------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | name | varchar(100) | NO | | NULL | | | projects_id | int(11) | NO | MUL | NULL | | | created | datetime | YES | | NULL | | | modified | datetime | YES | | NULL | | +-------------+--------------+------+-----+---------+----------------+ mysql> DESCRIBE projects; +----------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +----------------+--------------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | name | varchar(100) | NO | | NULL | | | sub_clients_id | int(11) | NO | MUL | NULL | | | created | datetime | YES | | NULL | | | modified | datetime | YES | | NULL | | +----------------+--------------+------+-----+---------+----------------+ mysql> DESCRIBE sub_clients; +------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +------------+--------------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | name | varchar(100) | NO | | NULL | | | clients_id | int(11) | NO | MUL | NULL | | | created | datetime | YES | | NULL | | | modified | datetime | YES | | NULL | | +------------+--------------+------+-----+---------+----------------+ mysql> DESCRIBE clients; +----------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +----------+--------------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | name | varchar(100) | NO | | NULL | | | created | datetime | YES | | NULL | | | modified | datetime | YES | | NULL | | +----------+--------------+------+-----+---------+----------------+ I have set up the following associations in CakePHP: LogItem belongsTo SubProjects SubProject belongsTo Projects Project belongsTo SubClients SubClient belongsTo Clients Client hasMany SubClients SubClient hasMany Projects Project hasMany SubProjects SubProject hasMany LogItems Using 'cake bake' I have created the models, controllers (index, view add, edit and delete) and views, and things seem to function - as in I am able to perform simple CRUD operations successfully. The Question When editing a 'log item' at www.mydomain/log_items/edit I am presented with the view you would all suspect; namely the columns of the log_items table with the appropriate textfields/select boxes etc. I would also like to incorporate select boxes to choose the client, sub-client, project and sub-project in the 'log_items' edit view. Ideally the 'sub-client' select box should populate itself depending upon the 'client' chosen, the 'project' select box should also populate itself depending on the 'sub-client' selected etc, etc. I guess the way to go about populating the select boxes with relevant options is Ajax, but I am unsure of how to go about actually accessing a model from the child view of a indirectly related model, for example how to create a 'sub-client' select box in the 'log_items' edit view. I have have found this example: http://forum.phpsitesolutions.com/php-frameworks/cakephp/ajax-cakephp-dynamically-populate-html-select-dropdown-box-t29.html where someone achieves something similar for US states, counties and cities. However, I noticed in the database schema - which is downloadable from the site above link - that the database tables don't have any foreign keys, so now I'm wondering if I'm going about things in the correct manner. Any pointers and advice would be very much appreciated. Kind regards, Chris

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  • PHP setting cookies in a child class

    - by steve
    I am writing a custom session handler and for the life of me I cannot get a cookie to set in it. I'm not outputting anything to the browser before I set the cookie but it still doesn't work. Its killing me. The cookie will set if I set it in the script I define and call on the session handler with. If necessary I will post code. Any ideas people? <?php /* require the needed classes comment out what is not needed */ require_once("classes/sessionmanager.php"); require_once("classes/template.php"); require_once("classes/database.php"); $title=" "; //titlebar of the web browser $description=" "; $keywords=" "; //meta keywords $menutype="default"; //default or customer, customer is elevated $pagetitle="dflsfsf "; //title of the webpage $pagebody=" "; //body of the webpage $template=template::def_instance(); $database=database::def_instance(); $session=sessionmanager::def_instance(); $session->sessions(); session_start(); ?> and this is the one that actually sets the cookie for the session function write($session_id,$session_data) { $session_id = mysql_real_escape_string($session_id); $session_data = mysql_real_escape_string(serialize($session_data)); $expires = time() + 3600; $user_ip = $_SERVER['REMOTE_ADDR']; $bol = FALSE; $time = time(); $newsession = FALSE; $auth = FALSE; $query = "SELECT * FROM 'sessions' WHERE 'expires' > '$time'"; $sessions_result = $this->query($query); $newsession = $this->newsession_check($session_id,$sessions_result); while($sessions_array = mysql_fetch_array($sessions_result) AND $auth = FALSE) { $session_array = $this->strip($session_array); $auth = $this->auth_check($session_array,$session_id); } /* this is an authentic session. build queries and update it */ if($auth = TRUE AND $newsession = FALSE) { $session_data = mysql_real_escape_string($session_data); $update_query1 = "UPDATE 'sessions' SET 'user_ip' = '$user_ip' WHERE 'session_id' = '$session_id'"; $update_query2 = "UPDATE 'sessions' SET 'data' = '$session_data' WHERE 'session_id = '$session_id'"; $update_query3 = "UPDATE 'sessions' SET 'expires' = '$expires' WHERE 'session_id' = '$session_id'"; $this->query($update_query1); $this->query($update_query2); $this->query($update_query3); $bol = TRUE; } elseif($newsession = TRUE) { /* this is a new session, build and create it */ $random_number = $this->obtain_random(); $cookieval = hash("sha512",$random_number); setcookie("rndn",$cookieval); $query = "INSERT INTO sessions VALUES('$session_id','0','$user_ip','$random_number','$session_data','$expires')"; $this->query($query); //echo $cookieval."this is the cookie <<"; $bol = TRUE; } return $bol; }

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