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  • Read Parent nodes only from XML using LINQToXML

    - by ItsMeSri
    I have XML string that has parent nodes "Committee" and inside that another child node "Committee" is there. When I am using "from committee in xDocument.DescendantsAndSelf("Committee")" it is reading childnode also, but I don't want to read child nodes, I just want to read Parent nodes only. <Committee> <Position>STAFF</Position> <Appointment>1/16/2006</Appointment> <Committee>PPMSSTAFF</Committee> <CommitteeName>PPMS Staff</CommitteeName> <Expiration>12/25/2099</Expiration> </Committee> <Committee> <Position>STAFF</Position> <Appointment>4/16/2004</Appointment> <Committee>PMOSSTAFF</Committee> <CommitteeName>PPMS </CommitteeName> <Expiration>12/25/2099</Expiration> </Committee> XElement xDocument= XElement.Parse(xml); var committeeXmls = from Committee in xDocument.Descendants("Committee") select new { CommitteeName = Committee.Element("CommitteeName"), Position = Committee.Element("Position"), Appointment = Committee.Element("Appointment"), Expiration = Committee.Element("Expiration") }; int i = 0; foreach (var committeeXml in committeeXmls) { if (committeeXml != null) { drCommittee = dtCommittee.NewRow(); drCommittee["ID"] = ++i; drCommittee["CommitteeName"] = committeeXml.CommitteeName.Value; drCommittee["Position"] = committeeXml.Position.Value; drCommittee["Appointment"] = committeeXml.Appointment.Value; drCommittee["Expiration"] = committeeXml.Expiration.Value; dtCommittee.Rows.Add(drCommittee); // educationXml.GraduationDate.Value, educationXml.Major.Value); } }

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  • Cocoa Read NSInputStream from FTP connection

    - by Chuck
    Hi, I (apparently) manage to make a ftp connection, but fail to read anything from it, and with good cause: I don't reach the reading until the connection has timed out. Here's my code: NSHost *host = [NSHost hostWithAddress:@"127.0.0.1"]; [NSStream getStreamsToHost:host port:3333 inputStream:&iStream outputStream:&oStream]; NSMutableDictionary *settings = [NSMutableDictionary dictionaryWithCapacity:1]; [settings setObject:(NSString *)NSStreamSocketSecurityLevelTLSv1 forKey:(NSString *)kCFStreamSSLLevel]; [settings setObject:[NSNumber numberWithBool:YES] forKey:(NSString *)kCFStreamSSLAllowsAnyRoot]; [iStream retain]; [iStream setDelegate:self]; [iStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode]; CFReadStreamSetProperty((CFReadStreamRef)iStream, kCFStreamPropertySSLSettings, (CFTypeRef)settings);forKey:NSStreamSocketSecurityLevelKey]; [iStream open]; [oStream retain]; [oStream setDelegate:self]; [oStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode]; CFWriteStreamSetProperty((CFWriteStreamRef)oStream, kCFStreamPropertySSLSettings, (CFTypeRef)settings); forKey:NSStreamSocketSecurityLevelKey]; [oStream open]; NSMutableData *returnMessage = [NSMutableData dataWithLength: 300]; [iStream read: [returnMessage mutableBytes] maxLength: 300]; NSString *readData = [[NSString alloc] initWithBytes: [returnMessage bytes] length: 300 encoding: NSUTF8StringEncoding]; NSRunAlertPanel(@"response", readData, nil, nil, nil); I have not sent a request to the FTP to switch to ssl yet. Any help is greatly appreciated as I find Xcode quite horrible for debugging (no exception or error msg on failed steps what so ever). Chuck

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  • AS3: doesn't read Atom

    - by Vinzcent
    Hey, I want to read an Atom in Flex. I can see in the debugger that he can read the Atom and that there are entries, I can see each value. So far, so good. But when I want to assign a value from the atom to a variable, he never gives any text. It's always this: "". My code: ch.Name = xml.title; ch.Desc = xml.subtitle; ch.Updated = xml.updated; for each(var entry:XML in xml.entry) { var fee:Feed = new Feed(); fee.Name = entry.title; fee.Url = entry.link.@href; fee.Desc = entry.summary; fee.Updated = entry.updated; fee.Published = entry.published; ch.Children.addItem(fee); } For example this is the value ch.Name gets ch.Name = ""; But that's strange, because I can see in the debugger that it schould be "Tweakers.net". Thanks a lot, Vincent Sorry for my bad English.

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  • Convert function to read from string instead of file in C

    - by Dusty
    I've been tasked with updating a function which currently reads in a configuration file from disk and populates a structure: static int LoadFromFile(FILE *Stream, ConfigStructure *cs) { int tempInt; ... if ( fscanf( Stream, "Version: %d\n",&tempInt) != 1 ) { printf("Unable to read version number\n"); return 0; } cs->Version = tempInt; ... } to one which allows us to bypass writing the configuration to disk and instead pass it directly in memory, roughly equivalent to this: static int LoadFromString(char *Stream, ConfigStructure *cs) A few things to note: The current LoadFromFile function is incredibly dense and complex, reading dozens of versions of the config file in a backward compatible manner, which makes duplication of the overall logic quite a pain. The functions that generate the config file and those that read it originate in totally different parts of the old system and therefore don't share any data structures so I can't pass those directly. I could potentially write a wrapper, but again, it would need to handle any structure passed in in a backwards compatible manner. I'm tempted to just pass the file as is in as a string (as in the prototype above) and convert all the fscanf's to sscanf's but then I have to handle incrementing the pointer along (and potentially dealing with buffer overrun errors) manually. This has to remain in C, so no C++ functionality like streams can help here Am I missing a better option? Is there some way to create a FILE * that actually just points to a location in memory instead of on disk? Any pointers, suggestions or other help is greatly appreciated.

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  • C++ Newbie: Passing an fstream to a function to read data

    - by vgm64
    I have a text file named num.txt who's only contents is the line 123. Then I have the following: void alt_reader(ifstream &file, char* line){ file.read(line, 3); cout << "First Time: " << line << endl; } int main() { ifstream inFile; int num; inFile.open("num.txt"); alt_reader(inFile, (char*)&num); cout << "Second Time: " << num << endl; } The output is: First Time: 123 Second Time: 3355185 Can you help me figure out how to get an fstream that is read in a function still assign the variable in main? I'm doing this because alt_reader really has a lot more to it, but this is the part I'm stuck on. Thanks a lot for the help.

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  • Read alphanumeric characters from csv file in C#

    - by Prasad
    I am using the following code to read my csv file: public DataTable ParseCSV(string path) { if (!File.Exists(path)) return null; string full = Path.GetFullPath(path); string file = Path.GetFileName(full); string dir = Path.GetDirectoryName(full); //create the "database" connection string string connString = "Provider=Microsoft.ACE.OLEDB.12.0;" + "Data Source=\"" + dir + "\\\";" + "Extended Properties=\"text;HDR=Yes;FMT=Delimited;IMEX=1\""; //create the database query string query = "SELECT * FROM " + file; //create a DataTable to hold the query results DataTable dTable = new DataTable(); //create an OleDbDataAdapter to execute the query OleDbDataAdapter dAdapter = new OleDbDataAdapter(query, connString); //fill the DataTable dAdapter.Fill(dTable); dAdapter.Dispose(); return dTable; } But the above doesn't reads the alphanumeric value from the csv file. it reads only i either numeric or alpha. Whats the fix i need to make to read the alphanumeric values? Please suggest.

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  • XML/C#: Read content if only if attribute is correct

    - by Zach
    Hi Guys, I have an XML file as follows, and I'm trying to read the content of the Name tag, only if the attribute of the Record tag is what I want. (continued below code) The XML file is: <?xml version="1.0" encoding="utf-8" ?> <Database> <Record Number="1"> <Name>John Doe</Name> <Position>1</Position> <HoursWorked>290</HoursWorked> <LastMonthChecked>0310</LastMonthChecked> </Record> <Record Number="2"> <Name>Jane Doe</Name> <Position>1</Position> <HoursWorked>251</HoursWorked> <LastMonthChecked>0310</LastMonthChecked> </Record> </Database> This is the C# code I have so far: public static string GetName(int EmployeeNumber) { XmlTextReader DataReader = new XmlTextReader("Database.xml"); DataReader.MoveToContent(); while (DataReader.Read()) { if (DataReader.NodeType == XmlNodeType.Element && DataReader.HasAttributes && DataReader.Name == "Record") { DataReader.MoveToAttribute(EmployeeNumber); DataReader.MoveToContent(); if (DataReader.NodeType == XmlNodeType.Element && DataReader.Name == "Name") { return DataReader.ReadContentAsString(); } } } } So for example, if 2 is passed to the function, I want it to return the string "Jane Doe". I'm new to XML parsing, so any help would be appreciated. Thanks.

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  • SSIS: "Failure inserting into the read-only column <ColumnName>"

    - by Cory
    I have an Excel source going into an OLE DB destination. I'm inserting data into a view that has an INSTEAD OF trigger that handles all inserts. When I try to execute the package I receive this error: "Failure inserting into the read-only column ColumnName" What can I do to let SSIS know that this view is safe to insert into because there is an INSTEAD OF trigger that will handle the insert? EDIT (Additional info): Some more additional info. I have a flat file that is being inserted into a normalized database. My initial problem was how do I take a flat file and insert that data into multiple tables while keeping track of all the primary/foreign key relationships. My solution was to create a VIEW that mimicked the structure of the flat file and then create an INSTEAD OF trigger on that view. In my INSTEAD OF trigger I would handle the logic of maintaining all the relationships between tables My view looks something like this. CREATE VIEW ImportView AS SELECT CONVERT(varchar(100, NULL) AS CustomerName, CONVERT(varchar(100), NULL) AS Address1, CONVERT(varchar(100), NULL) AS Address2, CONVERT(varchar(100), NULL) AS City, CONVERT(char(2), NULL) AS State, CONVERT(varchar(250), NULL) AS ItemOrdered, CONVERT(int, NULL) AS QuantityOrdered ... I will never need to select from this view, I only use it to insert data into it from this flat file I receive. I need someway to tell SQL Server that the fields aren't really read only because there is an INSTEAD OF trigger on this view.

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  • How to read spring-application-context.xml and AnnotationConfigWebApplicationContext both in spring mvc

    - by Suvasis
    In case I want to read bean definitions from spring-application-context.xml, I would do this in web.xml file. <context-param> <param-name>contextConfigLocation</param-name> <param-value> /WEB-INF/applicationContext.xml </param-value> </context-param> <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> In case I want to read bean definitions through Java Configuration Class (AnnotationConfigWebApplicationContext), I would do this in web.xml <servlet> <servlet-name>appServlet</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <param-name>contextClass</param-name> <param-value> org.springframework.web.context.support.AnnotationConfigWebApplicationContext </param-value> </init-param> <init-param> <param-name>contextConfigLocation</param-name> <param-value> org.package.MyConfigAnnotatedClass </param-value> </init-param> </servlet> How do I use both in my application. like reading beans from both configuration xml file and annotated class. Is there a way to load spring beans in xml file while we are using AppConfigAnnotatedClass to instantiate/use rest of the beans.

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  • read text file from phone memory in android

    - by Sudhakar
    Hi..I just wanna create a text file into phone memory and have to read its content to display.Now i created a text file.But its not present in the path data/data/package-name/file name.txt & it didn't display the content on emulator. My code is.. public class PhonememAct extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); TextView tv=(TextView)findViewById(R.id.tv); FileOutputStream fos = null; try { fos = openFileOutput("Test.txt", Context.MODE_PRIVATE); } catch (FileNotFoundException e2) { // TODO Auto-generated catch block e2.printStackTrace(); } try { fos.write("Hai..".getBytes()); } catch (IOException e1) { // TODO Auto-generated catch block e1.printStackTrace(); } try { fos.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } FileInputStream fis = null; try { fis = openFileInput("Test.txt"); } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } int c; try { while((c=fis.read())!=-1) { tv.setText(c); setContentView(tv); //k += (char)c; } } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } try { fis.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } Thanks in adv.

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  • Minimum privileges to read SQL Jobs using SQL SMO

    - by Gustavo Cavalcanti
    I wrote an application to use SQL SMO to find all SQL Servers, databases, jobs and job outcomes. This application is executed through a scheduled task using a local service account. This service account is local to the application server only and is not present in any SQL Server to be inspected. I am having problems getting information on job and job outcomes when connecting to the servers using a user with dbReader rights on system tables. If we set the user to be sysadmin on the server it all works fine. My question to you is: What are the minimum privileges a local SQL Server user needs to have in order to connect to the server and inspect jobs/job outcomes using the SQL SMO API? I connect to each SQL Server by doing the following: var conn = new ServerConnection { LoginSecure = false, ApplicationName = "SQL Inspector", ServerInstance = serverInstanceName, ConnectAsUser = false, Login = user, Password = password }; var smoServer = new Server (conn); I read the jobs by reading smoServer.JobServer.Jobs and read the JobSteps property on each of these jobs. The variable server is of type Microsoft.SqlServer.Management.Smo.Server. user/password are of the user found in each SQL Server to be inspected. If "user" is SysAdmin on the SQL Server to be inspected all works ok, as well as if we set ConnectAsUser to true and execute the scheduled task using my own credentials, which grants me SysAdmin privileges on SQL Server per my Active Directory membership. Thanks!

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  • trying to read a delimited text file from resources - but it wont run

    - by Bigfatty
    I'm having a problem where instead of reading a text file from the location string, I changed it to read the text file from the resource location and it messes up my program. I've also used the insert snippet method to get most of this code, so it is safe to say I don't know what is going on. Could some one please help? 'reads the text out of a delimited text file and puts the words and hints into to separate arrays ' this works and made the program run ' Dim filename As String = Application.StartupPath + "\ProggramingList.txt" 'this dosnt work and brings back a Illegal characters in path error. dim filename as string = My.Resources.GamesList Dim fields As String() 'my text files are delimited Dim delimiter As String = "," Using parser As New TextFieldParser(filename) parser.SetDelimiters(delimiter) While Not parser.EndOfData ' Read in the fields for the current line fields = parser.ReadFields() ' Add code here to use data in fields variable. 'put the result into two arrays (the fields are the arrays im talking about). one holds the words, and one holds the corresponding hint Programingwords(counter) = Strings.UCase(fields(0)) counter += 1 'this is where the hint is at Programingwords(counter) = (fields(1)) counter += 1 End While End Using

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  • libpcap read packet size

    - by spicyramen
    I started to write an application which will read RTP/H.264 video packets from an existing .pcap file, I need to read the packet size. I tried to use packet-len or header-len, but it never displays the right number of bytes for packets (I'm using wireshark to verify packet size - under Length column). How to do it? This is part of my code: while (packet = pcap_next(handle,&header)) { u_char *pkt_ptr = (u_char *)packet; struct ip *ip_hdr = (struct ip *)pkt_ptr; //point to an IP header structure struct pcap_pkthdr *pkt_hdr =(struct pcap_pkthdr *)packet; unsigned int packet_length = pkt_hdr->len; unsigned int ip_length = ntohs(ip_hdr->ip_len); printf("Packet # %i IP Header length: %d bytes, Packet length: %d bytes\n",pkt_counter,ip_length,packet_length); Packet # 0 IP Header length: 180 bytes, Packet length: 104857664 bytes Packet # 1 IP Header length: 52 bytes, Packet length: 104857600 bytes Packet # 2 IP Header length: 100 bytes, Packet length: 104857600 bytes Packet # 3 IP Header length: 100 bytes, Packet length: 104857664 bytes Packet # 4 IP Header length: 52 bytes, Packet length: 104857600 bytes Packet # 5 IP Header length: 100 bytes, Packet length: 104857600 bytes Another option I tried is to use: pkt_ptr- I get: read_pcapfile.c:67:43: error: request for member ‘len’ in something not a structure or union

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  • How to read XML using XPath in Java

    - by kaibuki
    Hi guys, I want to read XML data using XPath in Java, so for the information I have gathered I am not able to parse XML according to my requirement. here is what I want to do: Get XML file from online via its URL, then use XPath to parse it, I want to create two methods in it. One is in which I enter a specific node attribute id, and I get all the child nodes as result, and second is suppose I just want to get a specific child node value only <?xml version="1.0"?><howto> <topic name="Java"> <url>http://www.rgagnonjavahowto.htm</url> <car>taxi</car> </topic> <topic ame="PowerBuilder"> <url>http://www.rgagnon/pbhowto.htm</url> <url>http://www.rgagnon/pbhowtonew.htm</url> </topic> <topic name="Javascript"> <url>http://www.rgagnon/jshowto.htm</url> </topic> <topic name="VBScript"> <url>http://www.rgagnon/vbshowto.htm</url> </topic></howto> In above example I want to read all the elements if I search via @name and also one function in which I just want the url from @name 'Javascript' only return one node element. I hope I cleared my question :) Thanks. Kai

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  • read text file in xcode

    - by danielDhobbs
    hello. i tried to read text file in xcode but this "EXC_BAD_ACCESS message showed up when i tried to build my program here is my code and i put inputA.txt file in the same folder with project file my friend told me that i should put txt file in debug folder is this why i cannot read txt file in this code? please help me... macbook user. int main (int argc, const char * argv[]) { FILE* fp; char mychar; char arr[50][2] = {0, }; int i = 0; int j, k; graphType* G_; G_ = (graphType*)malloc(sizeof(graphType)); Create(G_); fp = fopen("inputA.txt", "r"); //fp = fopen("inputB.txt", "r"); //fp = fopen("inputC.txt", "r"); while(1){ for(j = 0 ; j < 2 ; j++){ mychar = fgetc(fp); if(mychar == EOF) break; else if(mychar == ' ') continue; arr[i][j] = mychar; } i++; }

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  • how to make sure the non disclosure agreement is read

    - by Xin Qian Ch'ang
    Every time a user registers to our site we need to show a non-disclosure agreement. In order to continue the user has to accept it. My issue is that I have the NDA in all one page and the user does not really read it and accept (like we all do). What I want is to make sure the user reads the NDA and accepts it one he "read" it? What I have now is a simple jqeury validation if the user checks a box and click on accept. then it goes to the next page. Here's what i have <script> $(document).ready(function() { $('#go').click(function() { // check if checkbox is check and go to next page }); }); </script> <div> full nda <hr> <input type=checkbox> <input type=button value=go id=go> </div> Thanks

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  • How to Read Device Data From serial port

    - by Aamir Khurshid
    I have one device which sends data on COM port say on COM13. Now i want to read that data and display it in the RichTextBox or in any text control. I have written the application with the help of IO and IO.Ports but comport.DataRecived event does not fire, even though device is sending data on that port. I have some software on which i define the port number and it successfully display data, which insure me that data is receiving on the Port but i am unable to receive. Is there any way i can read data? comm.Parity = cboParity.Text;//None comm.StopBits = cboStop.Text;//One comm.DataBits = cboData.Text;//8 comm.BaudRate = cboBaud.Text;//9600 comm.DisplayWindow = rtbDisplay;//Null comm.PortName = "COM13"; comm.OpenPort(); cmdOpen.Enabled = false; cmdClose.Enabled = true; cmdSend.Enabled = true; public bool OpenPort() { if (comPort.IsOpen) { comPort.Close(); } comPort.DataReceived += new SerialDataReceivedEventHandler(comPort_DataReceived); comPort.PortName = _portName; comPort.Open();return true; }

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  • cakephp read and display from more than one related table

    - by z22
    I have 2 tables Users and Artists. User: id name password city_id state_id country_id Artist: id user_id description I wish to create add and edit form(single form acts as add and edit). But on click of edit link, I wish to fill in the form fields from user as well as artist table. How do i do that? Below is my controller code: public function artist_register() { $this->country_list(); if ($this->request->is('post')) { $this->request->data['User']['group_id'] = 2; if ($this->{$this->modelClass}->saveAll($this->request->data)) { $this->redirect(array('controller' => 'Users', 'action' => 'login')); } } $this->render('artist_update'); } public function artist_update($id) { $artist = $this->{$this->modelClass}->findByuser_id($id); $artist_id = $artist[$this->modelClass]['id']; if($this->request->is('get')) { $this->request->data = $this->{$this->modelClass}->read(null, $artist_id); $this->request->data = $this->{$this->modelClass}->User->read(null, $id); } else { if($this->{$this->modelClass}->save($this->request->data)) { $this->Session->setFlash('Your Profile has been updated'); $this->redirect(array('action' => 'index')); } } } The code doesnt work. how do i solve it?

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  • Can I get rid of this read lock?

    - by Pieter
    I have the following helper class (simplified): public static class Cache { private static readonly object _syncRoot = new object(); private static Dictionary<Type, string> _lookup = new Dictionary<Type, string>(); public static void Add(Type type, string value) { lock (_syncRoot) { _lookup.Add(type, value); } } public static string Lookup(Type type) { string result; lock (_syncRoot) { _lookup.TryGetValue(type, out result); } return result; } } Add will be called roughly 10/100 times in the application and Lookup will be called by many threads, many of thousands of times. What I would like is to get rid of the read lock. How do you normally get rid of the read lock in this situation? I have the following ideas: Require that _lookup is stable before the application starts operation. The could be build up from an Attribute. This is done automatically through the static constructor the attribute is assigned to. Requiring the above would require me to go through all types that could have the attribute and calling RuntimeHelpers.RunClassConstructor which is an expensive operation; Move to COW semantics. public static void Add(Type type, string value) { lock (_syncRoot) { var lookup = new Dictionary<Type, string>(_lookup); lookup.Add(type, value); _lookup = lookup; } } (With the lock (_syncRoot) removed in the Lookup method.) The problem with this is that this uses an unnecessary amount of memory (which might not be a problem) and I would probably make _lookup volatile, but I'm not sure how this should be applied. (John Skeets' comment here gives me pause.) Using ReaderWriterLock. I believe this would make things worse since the region being locked is small. Suggestions are very welcome.

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  • Object Oriented Perl interface to read from and write to a socket

    - by user654967
    I need a perl client-server implementation as a wrapper for a server in C#. A perl script passes the server address and port number and an input string to a module, this module has to create the socket and send the input string to the server. The data sent has to follow ISO-8859-1 encoding. On receiving the information, the client has to first receive 3 byte, then the next 8 bytes, this has the length of the data that has to be received next.. so based on the length the client has to read the next data. each of the data that is read has to be stored in a variable and sent another module for further processing. Currently this is what my perl client looks like..which I'm sure isn't right..could someone tell me how to do this..and set me on the right direction.. sub WriteInfo { my ($addr, $port, $Input) = @_; $socket = IO::Socket::INET->new( Proto => "tcp", PeerAddr => $addr, PeerPort => $port, ); unless ($socket) { die "cannot connect to remote" } while (1) { $socket->send($Input); } } sub ReadData { while (1) { my $ExecutionResult = $socket->recv( $recv_data, 3); my $DataLength = $socket->recv( $recv_data, 8); $DataLength =~ s/^0+// ; my $decval = hex($DataLength); my $Data = $socket->recv( $recv_data, $decval); return($Data); } thanks a lot.. Archer

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  • Using shared_ptr to implement RCU (read-copy-update)?

    - by yongsun
    I'm very interested in the user-space RCU (read-copy-update), and trying to simulate one via tr1::shared_ptr, here is the code, while I'm really a newbie in concurrent programming, would some experts help me to review? The basic idea is, reader calls get_reading_copy() to gain the pointer of current protected data (let's say it's generation one, or G1). writer calls get_updating_copy() to gain a copy of the G1 (let's say it's G2), and only one writer is allowed to enter the critical section. After the updating is done, writer calls update() to do a swap, and make the m_data_ptr pointing to data G2. The ongoing readers and the writer now hold the shared_ptr of G1, and either a reader or a writer will eventually deallocate the G1 data. Any new readers would get the pointer to G2, and a new writer would get the copy of G2 (let's say G3). It's possible the G1 is not released yet, so multiple generations of data my co-exists. template <typename T> class rcu_protected { public: typedef T type; typedef std::tr1::shared_ptr<type> rcu_pointer; rcu_protected() : m_data_ptr (new type()) {} rcu_pointer get_reading_copy () { spin_until_eq (m_is_swapping, 0); return m_data_ptr; } rcu_pointer get_updating_copy () { spin_until_eq (m_is_swapping, 0); while (!CAS (m_is_writing, 0, 1)) {/* do sleep for back-off when exceeding maximum retry times */} rcu_pointer new_data_ptr(new type(*m_data_ptr)); // as spin_until_eq does not have memory barrier protection, // we need to place a read barrier to protect the loading of // new_data_ptr not to be re-ordered before its construction _ReadBarrier(); return new_data_ptr; } void update (rcu_pointer new_data_ptr) { while (!CAS (m_is_swapping, 0, 1)) {} m_data_ptr.swap (new_data_ptr); // as spin_until_eq does not have memory barrier protection, // we need to place a write barrier to protect the assignments of // m_is_writing/m_is_swapping be re-ordered bofore the swapping _WriteBarrier(); m_is_writing = 0; m_is_swapping = 0; } private: volatile long m_is_writing; volatile long m_is_swapping; rcu_pointer m_data_ptr; };

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  • Thread-safety of read-only memory access

    - by Edmund
    I've implemented the Barnes-Hut gravity algorithm in C as follows: Build a tree of clustered stars. For each star, traverse the tree and apply the gravitational forces from each applicable node. Update the star velocities and positions. Stage 2 is the most expensive stage, and so is implemented in parallel by dividing the set of stars. E.g. with 1000 stars and 2 threads, I have one thread processing the first 500 stars and the second thread processing the second 500. In practice this works: it speeds the computation by about 30% with two threads on a two-core machine, compared to the non-threaded version. Additionally, it yields the same numerical results as the original non-threaded version. My concern is that the two threads are accessing the same resource (namely, the tree) simultaneously. I have not added any synchronisation to the thread workers, so it's likely they will attempt to read from the same location at some point. Although access to the tree is strictly read-only I am not 100% sure it's safe. It has worked when I've tested it but I know this is no guarantee of correctness! Questions Do I need to make a private copy of the tree for each thread? Even if it is safe, are there performance problems of accessing the same memory from multiple threads?

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  • Spring: Bean fails to read off values from external Properties file when using @Value annotation

    - by daydreamer
    XML Configuration <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:util="http://www.springframework.org/schema/util" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util.xsd"> <util:properties id="mongoProperties" location="file:///storage/local.properties" /> <bean id="mongoService" class="com.business.persist.MongoService"></bean> </beans> and MongoService looks like @Service public class MongoService { @Value("#{mongoProperties[host]}") private String host; @Value("#{mongoProperties[port]}") private int port; @Value("#{mongoProperties[database]}") private String database; private Mongo mongo; private static final Logger LOGGER = LoggerFactory.getLogger(MongoService.class); public MongoService() throws UnknownHostException { LOGGER.info("host=" + host + ", port=" + port + ", database=" + database); mongo = new Mongo(host, port); } public void putDocument(@Nonnull final DBObject document) { LOGGER.info("inserting document - " + document.toString()); mongo.getDB(database).getCollection(getCollectionName(document)).insert(document, WriteConcern.SAFE); } I write my MongoServiceTest as public class MongoServiceTest { @Autowired private MongoService mongoService; public MongoServiceTest() throws UnknownHostException { mongoRule = new MongoRule(); } @Test public void testMongoService() { final DBObject document = DBContract.getUniqueQuery("001"); document.put(DBContract.RVARIABLES, "values"); document.put(DBContract.PVARIABLES, "values"); mongoService.putDocument(document); } and I see failures in tests as 12:37:25.224 [main] INFO c.s.business.persist.MongoService - host=null, port=0, database=null java.lang.NullPointerException at com.business.persist.MongoServiceTest.testMongoService(MongoServiceTest.java:40) Which means bean was not able to read the values from local.properties local.properties ### === MongoDB interaction === ### host="127.0.0.1" port=27017 database=contract How do I fix this? update It doesn't seem to read off the values even after creating setters/getters for the fields. I am really clueless now. How can I even debug this issue? Thanks much!

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  • can't read XML via PHP

    - by jasmine
    I can't find the reason, only see the following error message. Input is not proper UTF-8, indicate encoding ! Bytes: 0x00 0x5D 0x5D 0x3E the followings are my php code $reader2 = new XMLReader(); $reader2->XML($xmlstring); $user_data=""; while ($reader2->read()) { if ($reader2->name == "user_id" && $reader2->nodeType == XMLReader::ELEMENT) { $reader2->read(); $user_data .=$reader2->value; } } $reader2->close(); The followings are XML data <?xml version="1.0" encoding="UTF-8" ?> <SOAP:Envelope xmlns:SOAP="http://www.w3.org/2003/05/soap-envelope" > <SOAP:Body > <user_id>1234567890</user_id> <greeting_name><![CDATA[ABCDEF ..yl/?]]></greeting_name> </SOAP:Body> </SOAP:Envelope> I try a lot of ways,but still can't find the solution. the greeting tag value may be chinese or English words.

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  • Read Cookies using Javascript

    - by Ajith
    I want to create a cookie using php,an also i need to read it using javascript.ie, by using setcookie('mycookie','hello',time()+34000) in php i am creating a cookie in my system.Now,i need to read it using javascript.Is it possible?If anybody knows please give me some idea.Please....help me.I am using javscript as follows ` function Get_Cookie( check_name ) { // first we'll split this cookie up into name/value pairs // note: document.cookie only returns name=value, not the other components var a_all_cookies = document.cookie.split( ';' ); var a_temp_cookie = ''; var cookie_name = ''; var cookie_value = ''; var b_cookie_found = false; // set boolean t/f default f for ( i = 0; i < a_all_cookies.length; i++ ) { // now we'll split apart each name=value pair a_temp_cookie = a_all_cookies[i].split( '=' ); // and trim left/right whitespace while we're at it cookie_name = a_temp_cookie[0].replace(/^\s+|\s+$/g, ''); // if the extracted name matches passed check_name if ( cookie_name == check_name ) { b_cookie_found = true; // we need to handle case where cookie has no value but exists (no = sign, that is): if ( a_temp_cookie.length > 1 ) { cookie_value = unescape( a_temp_cookie[1].replace(/^\s+|\s+$/g, '') ); } // note that in cases where cookie is initialized but no value, null is returned return cookie_value; break; } a_temp_cookie = null; cookie_name = ''; } if ( !b_cookie_found ) { return null; } } if (Get_Cookie('__gsb')) { alert('Found'); } `

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