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  • Use native HBitmap in C# while preserving alpha channel/transparency. Please check this code, it works on my computer...

    - by David
    Let's say I get a HBITMAP object/handle from a native Windows function. I can convert it to a managed bitmap using Bitmap.FromHbitmap(nativeHBitmap), but if the native image has transparency information (alpha channel), it is lost by this conversion. There are a few questions on Stack Overflow regarding this issue. Using information from the first answer of this question (How to draw ARGB bitmap using GDI+?), I wrote a piece of code that I've tried and it works. It basically gets the native HBitmap width, height and the pointer to the location of the pixel data using GetObject and the BITMAP structure, and then calls the managed Bitmap constructor: Bitmap managedBitmap = new Bitmap(bitmapStruct.bmWidth, bitmapStruct.bmHeight, bitmapStruct.bmWidth * 4, PixelFormat.Format32bppArgb, bitmapStruct.bmBits); As I understand (please correct me if I'm wrong), this does not copy the actual pixel data from the native HBitmap to the managed bitmap, it simply points the managed bitmap to the pixel data from the native HBitmap. And I don't draw the bitmap here on another Graphics (DC) or on another bitmap, to avoid unnecessary memory copying, especially for large bitmaps. I can simply assign this bitmap to a PictureBox control or the the Form BackgroundImage property. And it works, the bitmap is displayed correctly, using transparency. When I no longer use the bitmap, I make sure the BackgroundImage property is no longer pointing to the bitmap, and I dispose both the managed bitmap and the native HBitmap. The Question: Can you tell me if this reasoning and code seems correct. I hope I will not get some unexpected behaviors or errors. And I hope I'm freeing all the memory and objects correctly. private void Example() { IntPtr nativeHBitmap = IntPtr.Zero; /* Get the native HBitmap object from a Windows function here */ // Create the BITMAP structure and get info from our nativeHBitmap NativeMethods.BITMAP bitmapStruct = new NativeMethods.BITMAP(); NativeMethods.GetObjectBitmap(nativeHBitmap, Marshal.SizeOf(bitmapStruct), ref bitmapStruct); // Create the managed bitmap using the pointer to the pixel data of the native HBitmap Bitmap managedBitmap = new Bitmap( bitmapStruct.bmWidth, bitmapStruct.bmHeight, bitmapStruct.bmWidth * 4, PixelFormat.Format32bppArgb, bitmapStruct.bmBits); // Show the bitmap this.BackgroundImage = managedBitmap; /* Run the program, use the image */ MessageBox.Show("running..."); // When the image is no longer needed, dispose both the managed Bitmap object and the native HBitmap this.BackgroundImage = null; managedBitmap.Dispose(); NativeMethods.DeleteObject(nativeHBitmap); } internal static class NativeMethods { [StructLayout(LayoutKind.Sequential)] public struct BITMAP { public int bmType; public int bmWidth; public int bmHeight; public int bmWidthBytes; public ushort bmPlanes; public ushort bmBitsPixel; public IntPtr bmBits; } [DllImport("gdi32", CharSet = CharSet.Auto, EntryPoint = "GetObject")] public static extern int GetObjectBitmap(IntPtr hObject, int nCount, ref BITMAP lpObject); [DllImport("gdi32.dll")] internal static extern bool DeleteObject(IntPtr hObject); }

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  • who free's setvbuf buffer?

    - by Evan Teran
    So I've been digging into how the stdio portion of libc is implemented and I've come across another question. Looking at man setvbuf I see the following: When the first I/O operation occurs on a file, malloc(3) is called, and a buffer is obtained. This makes sense, your program should have a malloc in it for I/O unless you actually use it. My gut reaction to this is that libc will clean up its own mess here. Which I can only assume it does because valgrind reports no memory leaks (they could of course do something dirty and not allocate it via malloc directly... but we'll assume that it literally uses malloc for now). But, you can specify your own buffer too... int main() { char *p = malloc(100); setvbuf(stdio, p, _IOFBF, 100); puts("hello world"); } Oh no, memory leak! valgrind confirms it. So it seems that whenever stdio allocates a buffer on its own, it will get deleted automatically (at the latest on program exit, but perhaps on stream close). But if you specify the buffer explicitly, then you must clean it up yourself. There is a catch though. The man page also says this: You must make sure that the space that buf points to still exists by the time stream is closed, which also happens at program termination. For example, the following is invalid: Now this is getting interesting for the standard streams. How would one properly clean up a manually allocated buffer for them, since they are closed in program termination? I could imagine a "clean this up when I close flag" inside the file struct, but it get hairy because if I read this right doing something like this: setvbuf(stdio, 0, _IOFBF, 100); printf("hello "); setvbuf(stdio, 0, _IOLBF, 100); printf("world\n"); would cause 2 allocations by the standard library because of this sentence: If the argument buf is NULL, only the mode is affected; a new buffer will be allocated on the next read or write operation.

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  • Ruby zlib deflate massive data

    - by Bub Bradlee
    I'm trying to use Zlib::Deflate.deflate on a massive file (4 gigs). There are obvious problems with doing that, the first of which being that I can't load the entire file into memory all at once. Zlib::GzipWriter would work, since it works with streams, but it's not zlib compression. Any ideas?

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  • Create certificate for a client app in .NET

    - by galets
    I'm looking for a server app to be routinely generating certificates for client applications using self-signed root. Is there any streamlined process in .NET to programmatically generate those certificates? I can, of course, keep spawning makecert or openssl, but I was looking for more programmatic, in-memory method, when you just get X509Certificate on output. If someone got a code snippet, can you please share?

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  • Adding Parsekit To An Xcode Project

    - by Garry
    I am trying to add the Parsekit framework to my OSX Xcode project. I've never added a 3rd party framework before and I can't get it to work right. I dragged the included Xcode project into my 'Groups & Files' pane and chose to Add it to my project. I then dragged Parsekit.framework underneath the Link Binary With Libraries heading. Then I double-clicked my target app and added Parsekit as a Direct Dependency. I also added libicucore.dylib as a Linked Library (as it says to do this on their site). Finally, in the Build settings tab of my target info I set the Header Search Paths to /Users/path/to/include/directory and the Other Linker Flags to -ObjC -all_load. Running this as a debug build work fine with no errors. However, when I build my app to release and then try to run the executable created, the app fails to load with the following error message: MyApp cannot be opened because of a problem. Check with the developer to make sure myApp works with this version of Mac OS X. Here is the dump from the crash reporter: Process: MyApp [11658] Path: /Users/Garry/Programming/Xcode/Mac/MyApp/build/Release/MyApp.app/Contents/MacOS/MyApp Identifier: com.yourcompany.MyApp Version: ??? (???) Code Type: X86-64 (Native) Parent Process: launchd [135] Date/Time: 2010-05-24 17:08:08.475 +0100 OS Version: Mac OS X 10.6.3 (10D573) Report Version: 6Interval Since Last Report: 133300 sec Crashes Since Last Report: 3 Per-App Crashes Since Last Report: 3 Anonymous UUID: DF0265E4-B5A0-45E1-8B71-D52A27CFDDCA Exception Type: EXC_BREAKPOINT (SIGTRAP) Exception Codes: 0x0000000000000002, 0x0000000000000000 Crashed Thread: 0 Dyld Error Message: Library not loaded: @executable_path/../Frameworks/ParseKit.framework/Versions/A/ParseKit Referenced from: /Users/Garry/Programming/Xcode/Mac/MyApp/build/Release/MyApp.app/Contents/MacOS/MyApp Reason: image not found Model: MacBookPro5,5, BootROM MBP55.00AC.B03, 2 processors, Intel Core 2 Duo, 2.53 GHz, 4 GB, SMC 1.47f2 Graphics: NVIDIA GeForce 9400M, NVIDIA GeForce 9400M, PCI, 256 MB Memory Module: global_name AirPort: spairport_wireless_card_type_airport_extreme (0x14E4, 0x8D), Broadcom BCM43xx 1.0 (5.10.91.27) Bluetooth: Version 2.3.1f4, 2 service, 2 devices, 1 incoming serial ports Network Service: AirPort, AirPort, en1 Network Service: Ethernet Adaptor (en6), Ethernet, en6 Serial ATA Device: Hitachi HTS545025B9SA02, 232.89 GB Serial ATA Device: HL-DT-ST DVDRW GS23N USB Device: Built-in iSight, 0x05ac (Apple Inc.), 0x8507, 0x24400000 USB Device: Internal Memory Card Reader, 0x05ac (Apple Inc.), 0x8403, 0x26500000 USB Device: IR Receiver, 0x05ac (Apple Inc.), 0x8242, 0x04500000 USB Device: Apple Internal Keyboard / Trackpad, 0x05ac (Apple Inc.), 0x0237, 0x04600000 USB Device: BRCM2046 Hub, 0x0a5c (Broadcom Corp.), 0x4500, 0x06100000 USB Device: Bluetooth USB Host Controller, 0x05ac (Apple Inc.), 0x8213, 0x06110000 After building the app, in addition to the executable file, Xcode is also creating a file called MyApp.app.dSYM. Any idea what that is?? I am developing with Xcode 3.2.2 on an Intel MBP running 10.6.3. Many thanks for any help offered.

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  • iphone: caching and updating xml fields

    - by pJosh
    Thanks for your help. Here I have another question. I get the data through XMLParsing, now I want to store it in iphone's cache, and the XML Fields are updates every 12 hours.how can i check that XML Fields are change or not? and how can I store the data in iphone's cache memory so that evry it does not has to interact with web. Can anybody please help me???

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  • Subclassing a window from a thread in c#

    - by user258651
    I'm creating a thread that looks for a window. When it finds the window, it overrides its windowproc, and handles WM_COMMAND and WM_CLOSE. Here's the code that looks for the window and subclasses it: public void DetectFileDialogProc() { Window fileDialog = null; // try to find the dialog twice, with a delay of 500 ms each time for (int attempts = 0; fileDialog == null && attempts < 2; attempts++) { // FindDialogs enumerates all windows of class #32770 via an EnumWindowProc foreach (Window wnd in FindDialogs(500)) { IntPtr parent = NativeMethods.User32.GetParent(wnd.Handle); if (parent != IntPtr.Zero) { // we're looking for a dialog whose parent is a dialog as well Window parentWindow = new Window(parent); if (parentWindow.ClassName == NativeMethods.SystemWindowClasses.Dialog) { fileDialog = wnd; break; } } } } // if we found the dialog if (fileDialog != null) { OldWinProc = NativeMethods.User32.GetWindowLong(fileDialog.Handle, NativeMethods.GWL_WNDPROC); NativeMethods.User32.SetWindowLong(fileDialog.Handle, NativeMethods.GWL_WNDPROC, Marshal.GetFunctionPointerForDelegate(new WindowProc(WndProc)).ToInt32()); } } And the windowproc: public IntPtr WndProc(IntPtr hWnd, uint msg, IntPtr wParam, IntPtr lParam) { lock (this) { if (!handled) { if (msg == NativeMethods.WM_COMMAND || msg == NativeMethods.WM_CLOSE) { // adding to a list. i never access the window via the hwnd from this list, i just treat it as a number _addDescriptor(hWnd); handled = true; } } } return NativeMethods.User32.CallWindowProc(OldWinProc, hWnd, msg, wParam, lParam); } This all works well under normal conditions. But I am seeing two instances of bad behavior in order of badness: If I do not close the dialog within a minute or so, the app crashes. Is this because the thread is getting garbage collected? This would kind of make sense, as far as GC can tell the thread is done? If this is the case, (and I don't know that it is), how can I make the thread stay around as long as the dialog is around? If I immediately close the dialog with the 'X' button (WM_CLOSE) the app crashes. I believe its crashing in the windowproc, but I can't get a breakpoint in there. I'm getting an AccessViolationException, The exception says "Attempted to read or write protected memory. This is often an indication that other memory is corrupt." Its a race condition, but of what I don't know. FYI, I had been reseting the old windowproc once I processed the commands, but that was crashing even more often! Any ideas on how I can solve these issues?

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  • How get page size from MemoryStream or Byte ?

    - by Nakul Chaudhary
    I have images of active report in database, when i get into bytes and convert into memory stream so it can pass to active report viewer then how i get paper size of paper display in active report? My code : Dim repmem As New System.IO.MemoryStream(rptBytes) repmem.Position = 0 Viewer1.Document.Load(repmem)

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  • Concerns with compressing sensitive data in OSX

    - by Derek Adair
    Hi, I have some really sensitive data that I am trying to compress and back up so I can reformat. It's absolutely imperative that nothing happens to these files. I'm a developer so I have very little room for error... plus I'd really hate it if any of my .mp3's got corrupted! File Formats Include... .mp3 .php .js .ai - .psd - .flv (and many more) Is the mac OSX file compression safe enough? Or should I look elsewhere? Is there a more efficient/secure file-format other than .zip (i'm assuming so...)

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  • How low-power can a home server get?

    - by Halik
    I've got quite simple question actually. How green, low-power and efficient x86 home server can I build using consumer parts with rather constrained budget. After looking through some Google hits I've found out that system based on dual-core atom, some modest mITX board (gigabit lan, integrated audio and gfx etc), one RAM module and one 'green' WD HDD, powered by picoITX PSU uses about 30W at idle up to 40 at load. Can you get lower (or how much lower) then that? Maybe some VIA nano chips, or single core atom? My home server would take care of some back-upping mixed with little ftp/http traffic.

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  • Application Freezing after some idle time

    - by Rakib Hasan
    Hello, I am developing a software using C# 2.0 which uses about 200MB of memory and occasionally high CPU. The problem is, when i am leaving my machine idle for about 20-30 mins with the application running, after i come back and try to use the application, it freezes for about 2 mins, then becomes interactive. Why does this happen? Is there any way to avoid this? Thank you all. Regards, -Rakib

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  • Converting gzip files to bzip2 efficiently

    - by sundar
    I have a bunch of gzip files that I have to convert to bzip2 every now and then. Currently, I'm using a shell script that simply 'gunzip's each file and then 'bzip2's it. Though this works, it takes a lot of time to complete. Is it possible to make this process more efficient? I'm ready to take a dive and look into gunzip and bzip2's source codes if necessary, but I just want to be sure of the payoff. Is there any hope of improving the efficiency of the process?

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  • Monitoring and terminating a hanged process in Linux

    - by Yoav
    Hi, I'm writing a script that runs many simultaneous processes that run the "dig" command. Once in a while (relatively rare, but happens in every run since I run dig many times) the dig command hangs with 0% CPU. Therefore, my script never terminates. I've created a monitor process for each dig command I run, which terminates it after a while, but I was wondering if there isn't a simpler and more efficient way to run a process with a pre-determined "expiration date", i.e. if the process runs more then X seconds it gets a signal that terminates it. Thanks!

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  • Fiddler - Daily stop start

    - by weismat
    What is the best way to stop/start Fiddler as a daily task? I am usin Fiddler to monitor/logs https trafficon machine which runs fully automated and runs software which is not controlled by me, but uses https. My machine stopped yesterday because Fiddler went out of memory after running over 3 days and now I want to have a clean way to start/stop it. I guess I could just specify a process duration in the task manager, but I would prefer something cleaner, especially to avoid issues when things are started manually.

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  • io operations in compilers

    - by Aastha
    How are constructs of io operations handled by a compiler? Like the RTL mapping for memory related operations which is done in a compiler at the time of target code generation, where and how exactly is the same done for io operations? How are the appeoaches different for processors supporting MMIO and I/O mapped I/O? Are there any optimizations done for the io operations in compilers?

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  • Switch from Microsofts STL to STLport

    - by Laserallan
    Hi! I'm using quite much STL in performance critical C++ code under windows. One possible "cheap" way to get some extra performance would be to change to a faster STL library. According to this post STLport is faster and uses less memory, however it's a few years old. Has anyone made this change recently and what were your results?

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  • How does SSMS and SQL Server Licensing work?

    - by DrewK
    Could not get a efficient enough answer from MSFT or some of their vendors. Trying to determine exactly how the licensing works before dropping the money on it. Looking to get Server/CAL. We will have the server at our datacenter and then be using SSMS remote on each developers computer. That is, installing SSMS on all developers machine. I am not familiar with MSFT licensing (postgresql & mysql). If I were to pay for the server license and 5 CALs does that mean we can install SSMS locally on each machine. Does each CAL have a specific lic. # that is entered when installing SSMS? We were messing with just the trial edition and the only way I know of installing SSMS is using the full sql server install and choosing only SSMS, it still requires a license number. Any information would be very useful.

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  • Sqlite / SQLAlchemy: how to enforce Foreign Keys?

    - by Nick Perkins
    The new version of SQLite has the ability to enforce Foreign Key constraints, but for the sake of backwards-compatibility, you have to turn it on for each database connection separately! sqlite> PRAGMA foreign_keys = ON; I am using SQLAlchemy -- how can I make sure this always gets turned on? What I have tried is this: engine = sqlalchemy.create_engine('sqlite:///:memory:', echo=True) engine.execute('pragma foreign_keys=on') ...but it is not working!...What am I missing?

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