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  • Is there a way to receive receive data as unsugned char over UDP on QT

    - by user269037
    I need to send floating point numbers using UDP connection to a QT application. Now in QT the only function available is qint64 readDatagram ( char * data, qint64 maxSize, QHostAddress * address = 0, quint16 * port = 0 ) which accepts data in the form of signed character buffer. I can convert my float into a string and send it but it will obviously not be very efficient converting a 4 byte float into a much longer sized character buffer. I got hold of these 2 functions to convert a 4 byte float into an unsinged 32 bit integer to transfer over network which works fine for a simple c++ udp program but for QT I need to receive the data as unsigned char. Is it possible to avoid converting the floatinf point data into a string and then sending it ?? uint32_t htonf(float f) { uint32_t p; uint32_t sign; if (f < 0) { sign = 1; f = -f; } else { sign = 0; } p = ((((uint32_t)f)&0x7fff)<<16) | (sign<<31); // whole part and sign p |= (uint32_t)(((f - (int)f) * 65536.0f))&0xffff; // fraction return p; } float ntohf(uint32_t p) { float f = ((p16)&0x7fff); // whole part f += (p&0xffff) / 65536.0f; // fraction if (((p>>31)&0x1) == 0x1) { f = -f; } // sign bit set return f; }

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  • Dynamically building and updating Histograms with JFreeChart

    - by job
    I've got a stream of incoming data that I would like to plot using a simple histogram. I don't know the range of values, or the proper resolution or bin width to use for the histogram. SimpleHistogramDataset provides some of this functionality, but I don't want to have to deal with catching exceptions in order to add new bins if the new value isn't covered. In addition, it doesn't easily allow me to rebuild the histogram using a different bin width (perhaps an integer multiples of some initial set width). Is there an easy way to accomplish this with JFreeChart or some alternate charting library, or am I going to have to write my own class here?

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  • Quick, beginner MASM register question - DX:AX

    - by Francisco P.
    Hello, I am currently studying for an exam I'll have on x86 assembly. I didn't have much luck googling for ":", too common of a punctuation mark :/ IDIV - Signed Integer Division Usage: IDIV src Modifies flags: (AF,CF,OF,PF,SF,ZF undefined) Signed binary division of accumulator by source. If source is a byte value, AX is divided by "src" and the quotient is stored in AL and the remainder in AH. If source is a word value, DX:AX is divided by "src", and the quotient is stored in AL and the remainder in DX. Taken from "Intel Opcodes and Mnemonics" What does DX:AX mean? Thanks a lot for your time :)

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  • Java: What are the various available security settings for applets

    - by bguiz
    I have an applet that throws this exception when trying to communicate with the server (running on localhost). This problem is limited to Applets only - a POJO client is able to communicate with the exact same server without any problem. Exception in thread "AWT-EventQueue-1" java.security.AccessControlException: access denied (java.net .SocketPermission 127.0.0.1:9999 connect,resolve) at java.security.AccessControlContext.checkPermission(AccessControlContext.java:323) My applet.policy file's contents is: grant { permission java.security.AllPermission; }; My question is what are the other places where I need to modify my security settings to grant an Applet more security settings? Thank you. EDIT: Further investigation has lead me to find that this problem only occurs on some machines - but not others. So it could be a machine level (global) setting that is causing this, rather than a application-specific setting such as the one in the applet.policy file. EDIT: Another SO question: Socket connection to originating server of an unsigned Java applet This seems to describe the exact same problem, and Tom Hawtin - tackline 's answer provides the reason why (a security patch released that disallows applets from connecting to localhost). Bearing this in mind, how do I grant the applet the security settings such that in can indeed run on my machine. Also why does it run as-is on other machines but not mine?

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  • Jacob + Microsoft SpeechAPI trouble

    - by guai
    Following groovy code kills JVM on SetInterest method invocation It uses Scriptom, the groovy DSL for Jacob Spend whole day searching SAPI's SPFEI macro to rewrite it in groovy. Don't sure does it came out right. Or maybe other bugs %) Help welcomed import org.codehaus.groovy.scriptom.* import static org.codehaus.groovy.scriptom.tlb.sapi.SpeechVoiceSpeakFlags.* import static org.codehaus.groovy.scriptom.tlb.sapi.SpeechRunState.* import static org.codehaus.groovy.scriptom.tlb.sapi.SpeechLib.* import static org.codehaus.groovy.scriptom.tlb.sapi.SPEVENTENUM.* def spfei(Integer[] args) { res = 1<<SPEI_RESERVED1 | 1<<SPEI_RESERVED2 args.each {res |= 1<<it} res } Scriptom.inApartment { def voice = new ActiveXObject('SAPI.SpVoice') evtsrc = voice.toInterface(ISpEventSource) evtsrc.setInterest(spfei(SPEI_WORD_BOUNDARY), spfei(SPEI_WORD_BOUNDARY)) evtsrc.events.Callbacks = {args -> println 'jjj'} voice.speak "Hello, world", SVSFlagsAsync }

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  • WPF DataGridTextColumn Can't type point for float data

    - by Alvin
    I had a WPF DataGrid and use DataGridTextColumn Binding to a Collection. The items in Collection had some float property. When my program launched, I modify the value of float property in DataGrid, if I type a integer value, it works well. But if I type char . for a float value, char . can't be typed. I had to type all the numbers first, and then jump to the . position to type char . to finish my input. So how can I type . in my situation? Thanks.

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  • JNA-Mapping Delphi Function

    - by Florian
    Hi! How do i map this function with JNA: Delphi code: function getData(InData1: PChar; InData2: PChar; Data: TArray16; var OutData1: PChar; var OutData2: PChar): integer; stdcall; with: TArray16 = array[0..15] of char; The int value that is returned can be 0 for Error or 1 for right execution; My suggestion is: Java code: int getData(String inData1, String inData2, byte[] data, byte[] outData1 byte[] outData2); The problem is that the function of the dll returns 0. I also tried other Datatypes, but it hasn't worked jet. I think the problem is that the dll function can't write to the parameters outData1 and outData2. Who can help me?....Thanks!!

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  • radiobutton not working in allkeys

    - by gerred
    i have a radiobutton built throught my code. this is the code for that. dim 1 as intereger = 0 Dim rd As New RadioButton rd.ID = "rd_" & i rd.GroupName = "rd_g" TD.Controls.Add(rd) i = i+1 the reason i gave groupname is so that when i select the radiobutton only one is selected at one time and not all. but this creates a problem in my save button. here's the code for that - For Each key As String In Request.Form.AllKeys If key.Contains("rd_") Then Dim temp1 As String = key.Substring(key.IndexOf("rd_")).Replace("rd_", "") Dim id As Integer = Val(temp) If id 0 Then SQL = "select .... " In the Request.Form.AllKeys I only get the groupname and not the ID of the radiobutton that i need. what am i doing wrong?

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  • Creating line graph/chart in vb.net (VS2008)

    - by typoknig
    I am reluctant to ask this question because a lot of similar questions have been asked, but after reading through them I am not getting the info I need. I am trying to follow this tutorial and I think it is going to work ok, but I have a lot of data to put in and the tutorial has the reader create the chart data points manually. I want the data points to be generated from an integer which can change while the program is running (thus the chart size needs to change) and the y coordinate of the data points needs to come from an array. I have attempted to "bind" the data but I am messing it up somehow and I don't even think that is the best way to do what I want. Also, I do not have to use the methods suggested in the tutorial, I am looking for the highest quality most efficient way to generate a line graph in vb.net (VS2008) based on the criteria I previously mentioned.

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  • [MFC] I can't re-parent a window

    - by John
    Following on from this question, now I have a clearer picture what's going on... I have a MFC application with no main window, which exposes an API to create dialogs. When I call some of these methods repeatedly, the dialogs created are parented to each other instead of all being parented to the desktop... I have no idea why. But anyway even after creation, I am unable to change the parent back to NULL or CWnd::GetDesktopWindow()... if I call SetParent followed by GetParent, nothing has changed. So apart from the really weird question of why Windows is magically parenting each dialog to the last one created, is there anything I'm missing to be able to set these windows as children of the desktop? UPDATED: I have found the reason for all this, but not the solution. From my dialog constructor, we end up in: BOOL CDialog::CreateIndirect(LPCDLGTEMPLATE lpDialogTemplate, CWnd* pParentWnd, void* lpDialogInit, HINSTANCE hInst) { ASSERT(lpDialogTemplate != NULL); if (pParentWnd == NULL) pParentWnd = AfxGetMainWnd(); m_lpDialogInit = lpDialogInit; return CreateDlgIndirect(lpDialogTemplate, pParentWnd, hInst); } Note: if (pParentWnd == NULL)pParentWnd = AfxGetMainWnd(); The call-stack from my dialog constructor looks like this: mfc80d.dll!CDialog::CreateIndirect(const DLGTEMPLATE * lpDialogTemplate=0x005931a8, CWnd * pParentWnd=0x00000000, void * lpDialogInit=0x00000000, HINSTANCE__ * hInst=0x00400000) mfc80d.dll!CDialog::CreateIndirect(void * hDialogTemplate=0x005931a8, CWnd * pParentWnd=0x00000000, HINSTANCE__ * hInst=0x00400000) mfc80d.dll!CDialog::Create(const char * lpszTemplateName=0x0000009d, CWnd * pParentWnd=0x00000000) mfc80d.dll!CDialog::Create(unsigned int nIDTemplate=157, CWnd * pParentWnd=0x00000000) MyApp.exe!CMyDlg::CMyDlg(CWnd * pParent=0x00000000)

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  • Get special numbers from a random number generator

    - by Wikeno
    I have a random number generator: int32_t ksp_random_table[GENERATOR_DEG] = { -1726662223, 379960547, 1735697613, 1040273694, 1313901226, 1627687941, -179304937, -2073333483, 1780058412, -1989503057, -615974602, 344556628, 939512070, -1249116260, 1507946756, -812545463, 154635395, 1388815473, -1926676823, 525320961, -1009028674, 968117788, -123449607, 1284210865, 435012392, -2017506339, -911064859, -370259173, 1132637927, 1398500161, -205601318, }; int front_pointer=3, rear_pointer=0; int32_t ksp_rand() { int32_t result; ksp_random_table[ front_pointer ] += ksp_random_table[ rear_pointer ]; result = ( ksp_random_table[ front_pointer ] >> 1 ) & 0x7fffffff; front_pointer++, rear_pointer++; if (front_pointer >= GENERATOR_DEG) front_pointer = 0; if (rear_pointer >= GENERATOR_DEG) rear_pointer = 0; return result; } void ksp_srand(unsigned int seed) { int32_t i, dst=0, kc=GENERATOR_DEG, word, hi, lo; word = ksp_random_table[0] = (seed==0) ? 1 : seed; for (i = 1; i < kc; ++i) { hi = word / 127773, lo = word % 127773; word = 16807 * lo - 2836 * hi; if (word < 0) word += 2147483647; ksp_random_table[++dst] = word; } front_pointer=3, rear_pointer=0; kc *= 10; while (--kc >= 0) ksp_rand(); } I'd like know what type of pseudo random number generation algorithm this is. My guess is a multiple linear congruential generator. And is there a way of seeding this algorithm so that after 987721(1043*947) numbers it would return 15 either even-only, odd-only or alternating odd and even numbers? It is a part of an assignment for a long term competition and i've got no idea how to solve it. I don't want the final solution, I'd like to learn how to do it myself.

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  • Where to start on creating finger swipe navigation in an collection of items

    - by Thomas Stock
    Lets say I want to make a control to select any integer number by dragging on a "bar" with numbers: (156 is selected) Mousedown on "159" and dragging towards the left and then doing mouseup changes the control to this: (160 is selected) I've been experimenting for the past 3 hours but I'm inexperienced in Silverlight so I'm having problems getting started. My current guess is I should seperate this into 2 steps: Step 1: Build this control without swiping behavior. Just 2 buttons to go up a number or go down a number Step 2: Replace the buttons by handling mouse events. With my limited knowledge I think I would manage building a crappy control that does this, with very messy xaml and c# and lots of headaches when trying to apply styling and fancy state transitions, but I was hoping some xaml wizards could get me started with the basic approach? Edit: This is an implementation of what I'm trying to achieve in Silverlight: Iphone's datepicker:

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  • Advice using leaks in instruments for noobs

    - by Gyozo Kudor
    Hello I am pretty new to iphone development. I have run my app for the first time using the "Leaks" from "Instruments". It shows me several leaks around 20 the smallest is 32 bytes and there is one with 1KB. I have followed the memory management guidelines, (i (think i) understand how and when to use release, not to use it when adding to autorelease pools, for every copy, retain, init there should be a release,... etc). I don't think I understand the output of the Leaks in instruments. What does "Responsible library" and "Responsible frame" mean. Because there are some classes and methods i never used directly. Are there any good tutorials for debugging memory leaks in instruments or other advice you can give me regarding leaks. Thanks in advance. Here are the largest 2 leaks. Leaked Object # Address Size Responsible Library Responsible Frame Malloc 1.00 KB 0x4827400 1024 CFNetwork std::vector *, std::allocator * ::reserve(unsigned long) // i have no idea what this is. Leaked Object # Address Size Responsible Library Responsible Frame Malloc 128 Bytes 5 640 UIKit UIImagePickerLoadPhotoLibraryIfNecessary // so this means UIImagePicker is leaking memory? The first leak i get Leaked Object # Address Size Responsible Library Responsible Frame Malloc 128 Bytes 0x442dfd0 128 UIKit UIKeyboardInputManagerClassForInputMode I don't understand any of those.

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  • SWT Layout for absolute positioning with minimal-spanning composites

    - by pure.equal
    Hi, I'm writing a DND-editor where I can position elemtents (like buttons, images ...) freely via absolute positioning. Every element has a parent composite. These composites should span/grasp/embrace every element they contain. There can be two or more elements in the same composite and a composite can contain another composite. This image shows how it should look like. To achive this I wrote a custom layoutmanager: import org.eclipse.swt.SWT; import org.eclipse.swt.graphics.Point; import org.eclipse.swt.widgets.Composite; import org.eclipse.swt.widgets.Control; import org.eclipse.swt.widgets.Layout; public class SpanLayout extends Layout { Point[] sizes; int calcedHeight, calcedWidth, calcedX, calcedY; Point[] positions; /* * (non-Javadoc) * * @see * org.eclipse.swt.widgets.Layout#computeSize(org.eclipse.swt.widgets.Composite * , int, int, boolean) * * A composite calls computeSize() on its associated layout to determine the * minimum size it should occupy, while still holding all its child controls * at their minimum sizes. */ @Override protected Point computeSize(Composite composite, int wHint, int hHint, boolean flushCache) { int width = wHint, height = hHint; if (wHint == SWT.DEFAULT) width = composite.getBounds().width; if (hHint == SWT.DEFAULT) height = composite.getBounds().height; return new Point(width, height); } /* * (non-Javadoc) * * @see * org.eclipse.swt.widgets.Layout#layout(org.eclipse.swt.widgets.Composite, * boolean) * * Calculates the positions and sizes for the children of the passed * Composite, then places them accordingly by calling setBounds() on each * one. */ @Override protected void layout(Composite composite, boolean flushCache) { Control children[] = composite.getChildren(); for (int i = 0; i < children.length; i++) { calcedX = calcX(children[i]); calcedY = calcY(children[i]); calcedHeight = calcHeight(children[i]) - calcedY; calcedWidth = calcWidth(children[i]) - calcedX; if (composite instanceof Composite) { calcedX = calcedX - composite.getLocation().x; calcedY = calcedY - composite.getLocation().y; } children[i].setBounds(calcedX, calcedY, calcedWidth, calcedHeight); } } private int calcHeight(Control control) { int maximum = 0; if (control instanceof Composite) { if (((Composite) control).getChildren().length > 0) { for (Control child : ((Composite) control).getChildren()) { int calculatedHeight = calcHeight(child); if (calculatedHeight > maximum) { maximum = calculatedHeight; } } return maximum; } } return control.computeSize(SWT.DEFAULT, SWT.DEFAULT, true).y + control.getLocation().y; } private int calcWidth(Control control) { int maximum = 0; if (control instanceof Composite) { if (((Composite) control).getChildren().length > 0) { for (Control child : ((Composite) control).getChildren()) { int calculatedWidth = calcWidth(child); if (calculatedWidth > maximum) { maximum = calculatedWidth; } } return maximum; } } return control.computeSize(SWT.DEFAULT, SWT.DEFAULT, true).x + control.getLocation().x; } private int calcX(Control control) { int minimum = Integer.MAX_VALUE; if (control instanceof Composite) { if (((Composite) control).getChildren().length > 0) { for (Control child : ((Composite) control).getChildren()) { int calculatedX = calcX(child); if (calculatedX < minimum) { minimum = calculatedX; } } return minimum; } } return control.getLocation().x; } private int calcY(Control control) { int minimum = Integer.MAX_VALUE; if (control instanceof Composite) { if (((Composite) control).getChildren().length > 0) { for (Control child : ((Composite) control).getChildren()) { int calculatedY = calcY(child); if (calculatedY < minimum) { minimum = calculatedY; } } return minimum; } } return control.getLocation().y; } } The problem with it is that it always positions the composite at the position (0,0). This is because it tries to change the absolute positioning into a relative one. Lets say I position a image at position (100,100) and one at (200,200). Then it has to calculate the location of the composite to be at (100,100) and spanning the one at (200,200). But as all child positions are relative to their parents I have to change the positions of the children to remove the 100px offset of the parent. When the layout gets updated it moves everything to the top-left corner (as seen in the image) because the position of the image is not (100,100) but (0,0) since I tried to remove the 100px offset of the partent. Where is my error in reasoning? Is this maybe a totally wrong approach? Is there maybe an other way to achive the desired behavior? Thanks in advance! Best regards, Ed

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  • Floating point conversion from Fixed point algorithm

    - by Viks
    Hi, I have an application which is using 24 bit fixed point calculation.I am porting it to a hardware which does support floating point, so for speed optimization I need to convert all fixed point based calculation to floating point based calculation. For this code snippet, It is calculating mantissa for(i=0;i<8207;i++) { // Do n^8/7 calculation and store // it in mantissa and exponent, scaled to // fixed point precision. } So since this calculation, does convert an integer to mantissa and exponent scaled to fixed point precision(23 bit). When I tried converting it to float, by dividing the mantissa part by precision bits and subtracting the exponent part by precision bit, it really does' t work. Please help suggesting a better way of doing it.

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  • Delegate, BeginInvoke. EndInvoke - How to clean up multiple Async threat calls to the same delegate?

    - by Dan
    I've created a Delegate that I intend to call Async. Module Level Delegate Sub GetPartListDataFromServer(ByVal dvOriginal As DataView, ByVal ProgramID As Integer) Dim dlgGetPartList As GetPartListDataFromServer The following code I use in a method Dim dlgGetPartList As New GetPartListDataFromServer(AddressOf AsyncThreadMethod_GetPartListDataFromServer) dlgGetPartList.BeginInvoke(ucboPart.DataSource, ucboProgram.Value, AddressOf AsyncCallback_GetPartListDataFromServer, Nothing) The method runs and does what it needs to The Asyn callback is fired upon completion where I do an EndInvoke Sub AsyncCallback_GetPartListDataFromServer(ByVal ar As IAsyncResult) dlgGetPartList.EndInvoke(Nothing) End Sub It works as long as the method that starts the BeginInvoke on the delegate only ever runs while there is not a BeginInvoke/Thread operation already running. Problem is that the a new thread could be invoked while another thread on the delegate is still running and hasnt yet been EndInvoke'd. The program needs to be able to have the delegate run in more than one instance at a time if necessary and they all need to complete and have EndInvoke called. Once I start another BeginInvoke I lose the reference to the first BeginInvoke so I am unable to clean up the new thread with an EndInvoke. What is a clean solution and best practice to overcome this problem?

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  • Google Gears - Database - VACUUM

    - by Sirber
    With this code: var db = google.gears.factory.create('beta.database'); db.open('cominar'); db.execute('CREATE TABLE IF NOT EXISTS Ajax (AJAX_ID INTEGER PRIMARY KEY AUTOINCREMENT , MODULE TEXT, FUNCTION TEXT, CONTENT_JSON TEXT);'); db.execute('VACUUM;'); // nettoye la DB I'm trying to clean the database (VACUUM) the database at each initialisation but I get this error: Uncaught Error: Database operation failed. ERROR: authorization denied DETAILS: not authorized The database was created by me (the same page). Thank you!

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  • Hibernates generates VARBINARY column with JPA @Enumerated annotation

    - by tran
    Hibernates is generating a VARBINARY column with JPA @Enumerated annotation. I'm using SQL Server 2005 w/ JTDS driver. The mapping is dirt simple: @Basic @Enumerated(EnumType.ORDINAL) private MyEnum foo; I would have expected Hibernate to generate an integer column? I've also tried EnumType.STRING (expecting a varchar column) with no success. Note that my app works fine; the column type makes it hard to inspect the DB, and to issue adhoc SQL when poking at the database.

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  • BufferedReader.readLine() gives error java.net.SocketException: Software caused connection abort: re

    - by javatcp
    I am trying to code my program such that until the buffered reader gets something in readLine() from my tcp client it should keep running in the while loop checking but I get this error as soon as the program executes Mar 31, 2010 11:03:36 PM deswash.DESWashView$5 run SEVERE: null java.net.SocketException: Software caused connection abort: recv failed at java.net.SocketInputStream.socketRead0(Native Method) at java.net.SocketInputStream.read(SocketInputStream.java:129) at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:264) at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:306) at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:158) at java.io.InputStreamReader.read(InputStreamReader.java:167) at java.io.BufferedReader.fill(BufferedReader.java:136) at java.io.BufferedReader.readLine(BufferedReader.java:299) at java.io.BufferedReader.readLine(BufferedReader.java:362) at deswash.DESWashView$5.run(DESWashView.java:448) the second line in the following code throws the error while(running){ String temp = in.readLine(); if(!(temp.equals(null))){ int inid = Integer.parseInt(temp); stationList.add(inid); } }

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  • Why is setting HTML5's CanvasPixelArray values ridiculously slow and how can I do it faster?

    - by Nixuz
    I am trying to do some dynamic visual effects using the HTML 5 canvas' pixel manipulation, but I am running into a problem where setting pixels in the CanvasPixelArray is ridiculously slow. For example if I have code like: imageData = ctx.getImageData(0, 0, 500, 500); for (var i = 0; i < imageData.length; i += 4){ imageData.data[i] = buffer[i]; imageData.data[i + 1] = buffer[i + 1]; imageData.data[i + 2] = buffer[i + 2]; } ctx.putImageData(imageData, 0, 0); Profiling with Chrome reveals, it runs 44% slower than the following code where CanvasPixelArray is not used. tempArray = new Array(500 * 500 * 4); imageData = ctx.getImageData(0, 0, 500, 500); for (var i = 0; i < imageData.length; i += 4){ tempArray[i] = buffer[i]; tempArray[i + 1] = buffer[i + 1]; tempArray[i + 2] = buffer[i + 2]; } ctx.putImageData(imageData, 0, 0); My guess is that the reason for this slowdown is due to the conversion between the Javascript doubles and the internal unsigned 8bit integers, used by the CanvasPixelArray. Is this guess correct? Is there anyway to reduce the time spent setting values in the CanvasPixelArray?

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  • NSStepper ignores current NSTextField value

    - by JanX2
    I have the same initial problem as described in Integrate NSStepper with NSTextField: I need to have a NSTextField working with a NSStepper as being one control so that I can edit an integer value either by changing it directly on the text field or using the stepper up/down arrows. Using bindings as commented on by carlosb results in a usable UI. However, in the initial question carlosb describes the following: Problem is that if I edit the text field then click the stepper again it will forget about the value I manually edited and use the stepper's internal value. This is why I am posting a variation on this question again. carlosb's use of bindings doesn't solve this problem. This happens in both the current project I am working on and a test project I have created. The test project can be found at GitHub. You can download it there (even without git) via the "Download Source" button in the top right. Is there a clean way to solve this issue?

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  • Create ntp time stamp from gettimeofday

    - by krunk
    I need to calculate an ntp time stamp using gettimeofday. Below is how I've done it with comments on method. Look good to you guys? (minus error checking). Also, here's a codepad link. #include <unistd.h> #include <sys/time.h> const unsigned long EPOCH = 2208988800UL; // delta between epoch time and ntp time const double NTP_SCALE_FRAC = 4294967295.0; // maximum value of the ntp fractional part int main() { struct timeval tv; uint64_t ntp_time; uint64_t tv_ntp; double tv_usecs; gettimeofday(&tv, NULL); tv_ntp = tv.tv_sec + EPOCH; // convert tv_usec to a fraction of a second // next, we multiply this fraction times the NTP_SCALE_FRAC, which represents // the maximum value of the fraction until it rolls over to one. Thus, // .05 seconds is represented in NTP as (.05 * NTP_SCALE_FRAC) tv_usecs = (tv.tv_usec * 1e-6) * NTP_SCALE_FRAC; // next we take the tv_ntp seconds value and shift it 32 bits to the left. This puts the // seconds in the proper location for NTP time stamps. I recognize this method has an // overflow hazard if used after around the year 2106 // Next we do a bitwise AND with the tv_usecs cast as a uin32_t, dropping the fractional // part ntp_time = ((tv_ntp << 32) & (uint32_t)tv_usecs); }

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  • Trying to parse OpenCV YAML ouput with yaml-cpp

    - by Kenn Sebesta
    I've got a series of OpenCv generated YAML files and would like to parse them with yaml-cpp I'm doing okay on simple stuff, but the matrix representation is proving difficult. # Center of table tableCenter: !!opencv-matrix rows: 1 cols: 2 dt: f data: [ 240, 240] This should map into the vector 240 240 with type float. My code looks like: #include "yaml.h" #include <fstream> #include <string> struct Matrix { int x; }; void operator >> (const YAML::Node& node, Matrix& matrix) { unsigned rows; node["rows"] >> rows; } int main() { std::ifstream fin("monsters.yaml"); YAML::Parser parser(fin); YAML::Node doc; Matrix m; doc["tableCenter"] >> m; return 0; } But I get terminate called after throwing an instance of 'YAML::BadDereference' what(): yaml-cpp: error at line 0, column 0: bad dereference Abort trap I searched around for some documentation for yaml-cpp, but there doesn't seem to be any, aside from a short introductory example on parsing and emitting. Unfortunately, neither of these two help in this particular circumstance. As I understand, the !! indicate that this is a user-defined type, but I don't see with yaml-cpp how to parse that.

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  • how to use gettimeofday() or something equivalent with Visual Studio C++ 2008?

    - by make
    Hi, Could someone please help me to use gettimeofday() function with Visual Studio C++ 2008 on Windows XP? here is a code that I found somewhere on the net: #include < time.h > #include <windows.h> #if defined(_MSC_VER) || defined(_MSC_EXTENSIONS) #define DELTA_EPOCH_IN_MICROSECS 11644473600000000Ui64 #else #define DELTA_EPOCH_IN_MICROSECS 11644473600000000ULL #endif struct timezone { int tz_minuteswest; /* minutes W of Greenwich */ int tz_dsttime; /* type of dst correction */ }; int gettimeofday(struct timeval *tv, struct timezone *tz) { FILETIME ft; unsigned __int64 tmpres = 0; static int tzflag; if (NULL != tv) { GetSystemTimeAsFileTime(&ft); tmpres |= ft.dwHighDateTime; tmpres <<= 32; tmpres |= ft.dwLowDateTime; /*converting file time to unix epoch*/ tmpres -= DELTA_EPOCH_IN_MICROSECS; tmpres /= 10; /*convert into microseconds*/ tv->tv_sec = (long)(tmpres / 1000000UL); tv->tv_usec = (long)(tmpres % 1000000UL); } if (NULL != tz) { if (!tzflag) { _tzset(); tzflag++; } tz->tz_minuteswest = _timezone / 60; tz->tz_dsttime = _daylight; } return 0; } ... // call gettimeofday() gettimeofday(&tv, &tz); tm = localtime(&tv.tv_sec); Last yesr when I tested this code VC++6, it works fine. But now when I use VC++ 2008, I am getting error of exception handling. So is there any idea on how to use gettimeofday or something equivalent? Thanks for your reply and any help would be very appreciated:

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  • posix pthreads in c

    - by Codenotguru
    Iam new to c programming and needs some help. long *taskids[NUM_THREADS]; for(t=0; t<NUM_THREADS; t++) { taskids[t] = (long *) malloc(sizeof(long)); *taskids[t] = t; printf("Creating thread %ld\n", t); rc = pthread_create(&threads[t], NULL, PrintHello, (void *) taskids[t]); ... } This code fragment demonstrates how to pass a simple integer to each thread. The calling thread uses a unique data structure for each thread, insuring that each thread's argument remains intact throughout the program. Iam not able to understand how this is happening can somebody explain it??

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