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  • Is "Turn Off Windows write-cache buffer flushing" safe on a laptop?

    - by Earlz
    my laptop's internal harddrive is a bit slow. I looked at the drive properties and there are two options: [X] Enable write caching on the device [ ] Turn off windows write-cache buffer flushing on the device As you can see, the first option is checked already, but the second option isn't. I've heard the second option can really speed things up, but it also sounds very risky. Is it safe to do on a laptop that rarely is off of AC power? (but still has battery as well)

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  • Data Structures: What are some common examples of problems where "buffers" come into action?

    - by Dark Templar
    I was just wondering if there were some "standard" examples that everyone uses as a basis for explaining the nature of a problem that requires the use of a buffer. What are some well-known problems in the real world that can see great benefits from using a buffer? Also, a little background or explanation as to why the problem benefits from using a buffer, and how the buffer would be implemented, would be insightful for understanding the concept!

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  • How can I make Swig correctly wrap a char* buffer that is modified in C as a Java Something-or-other

    - by Ukko
    I am trying to wrap some legacy code for use in Java and I was quite happy to see that Swig was able to handle the header file and it generate a great wrapper that almost works. Now I am looking for the deep magic that will make it really work. In C I have a function that looks like this DLL_IMPORT int DustyVoodoo(char *buff, int len, char *curse); This integer returned by this function is an error code in case it fails. The arguments are buff is a character buffer len is the length of the data in the buffer curse the another character buffer that contains the result of calling DustyVoodoo So, you can see where this is going, the result is actually coming back via the third argument. Also len is confusing since it may be the length of both buffers, they are always allocated as being the same size in calling code but given what DustyVoodoo does I don't think that they need be the same. To be safe both buffers should be the same size in practice, say 512 chars. The C code generated for the binding is as follows: SWIGEXPORT jint JNICALL Java_pemapiJNI_DustyVoodoo(JNIEnv *jenv, jclass jcls, jstring jarg1, jint jarg2, jstring jarg3) { jint jresult = 0 ; char *arg1 = (char *) 0 ; int arg2 ; char *arg3 = (char *) 0 ; int result; (void)jenv; (void)jcls; arg1 = 0; if (jarg1) { arg1 = (char *)(*jenv)->GetStringUTFChars(jenv, jarg1, 0); if (!arg1) return 0; } arg2 = (int)jarg2; arg3 = 0; if (jarg3) { arg3 = (char *)(*jenv)->GetStringUTFChars(jenv, jarg3, 0); if (!arg3) return 0; } result = (int)PemnEncrypt(arg1,arg2,arg3); jresult = (jint)result; if (arg1) (*jenv)->ReleaseStringUTFChars(jenv, jarg1, (const char *)arg1); if (arg3) (*jenv)->ReleaseStringUTFChars(jenv, jarg3, (const char *)arg3); return jresult; } It is correct for what it does; however, it misses the fact that cursed is not just an input, it is altered by the function and should be returned as an output. It also does not know that the java Strings are really buffers and should be backed by a suitably sized array. I think that Swig can do the right thing here, I just can't figure out from the documentation how to tell Swig what it needs to know. Any typemap masers in the house?

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  • creating a Menu from SQLite values in Java

    - by shanahobo86
    I am trying to create a ListMenu using data from an SQLite database to define the name of each MenuItem. So in a class called menu.java I have defined the array String classes [] = {}; which should hold each menu item name. In a DBAdapter class I created a function so the user can insert info to a table (This all works fine btw). public long insertContact(String name, String code, String location, String comments, int days, int start, int end, String type) { ContentValues initialValues = new ContentValues(); initialValues.put(KEY_NAME, name); initialValues.put(KEY_CODE, code); initialValues.put(KEY_LOCATION, location); initialValues.put(KEY_COMMENTS, comments); initialValues.put(KEY_DAYS, days); initialValues.put(KEY_START, start); initialValues.put(KEY_END, end); initialValues.put(KEY_TYPE, type); return db.insert(DATABASE_TABLE, null, initialValues); } It would be the Strings inserted into KEY_NAME that I need to populate that String array with. Does anyone know if this is possible? Thanks so much for the help guys. If I implement that function by Sam/Mango the program crashes, am I using it incorrectly or is the error due to the unknown size of the array? DBAdapter db = new DBAdapter(this); String classes [] = db.getClasses(); edit: I should mention that if I manually define the array: String classes [] = {"test1", "test2", "test3", etc}; It works fine. The error is a NullPointerException Here's the logcat (sorry about the formatting). I hadn't initialized with db = helper.getReadableDatabase(); in the getClasses() function but unfortunately it didn't fix the problem. 11-11 22:53:39.117: D/dalvikvm(17856): Late-enabling CheckJNI 11-11 22:53:39.297: D/TextLayoutCache(17856): Using debug level: 0 - Debug Enabled: 0 11-11 22:53:39.337: D/libEGL(17856): loaded /system/lib/egl/libGLES_android.so 11-11 22:53:39.337: D/libEGL(17856): loaded /system/lib/egl/libEGL_adreno200.so 11-11 22:53:39.357: D/libEGL(17856): loaded /system/lib/egl/libGLESv1_CM_adreno200.so 11-11 22:53:39.357: D/libEGL(17856): loaded /system/lib/egl/libGLESv2_adreno200.so 11-11 22:53:39.387: I/Adreno200-EGLSUB(17856): <ConfigWindowMatch:2078>: Format RGBA_8888. 11-11 22:53:39.407: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x5c66d000 size:36593664 offset:32825344 fd:65 11-11 22:53:39.417: E/(17856): Can't open file for reading 11-11 22:53:39.417: E/(17856): Can't open file for reading 11-11 22:53:39.417: D/OpenGLRenderer(17856): Enabling debug mode 0 11-11 22:53:39.477: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x5ecd3000 size:40361984 offset:36593664 fd:68 11-11 22:53:40.507: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x61451000 size:7254016 offset:3485696 fd:71 11-11 22:53:41.077: I/Adreno200-EGLSUB(17856): <ConfigWindowMatch:2078>: Format RGBA_8888. 11-11 22:53:41.077: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x61c4c000 size:7725056 offset:7254016 fd:74 11-11 22:53:41.097: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x623aa000 size:8196096 offset:7725056 fd:80 11-11 22:53:41.937: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x62b7b000 size:8667136 offset:8196096 fd:83 11-11 22:53:41.977: D/memalloc(17856): /dev/pmem: Unmapping buffer base:0x61c4c000 size:7725056 offset:7254016 11-11 22:53:41.977: D/memalloc(17856): /dev/pmem: Unmapping buffer base:0x623aa000 size:8196096 offset:7725056 11-11 22:53:41.977: D/memalloc(17856): /dev/pmem: Unmapping buffer base:0x62b7b000 size:8667136 offset:8196096 11-11 22:53:42.167: I/Adreno200-EGLSUB(17856): <ConfigWindowMatch:2078>: Format RGBA_8888. 11-11 22:53:42.177: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x61c5d000 size:17084416 offset:13316096 fd:74 11-11 22:53:42.317: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x63853000 size:20852736 offset:17084416 fd:80 11-11 22:53:42.357: D/OpenGLRenderer(17856): Flushing caches (mode 0) 11-11 22:53:42.357: D/memalloc(17856): /dev/pmem: Unmapping buffer base:0x5c66d000 size:36593664 offset:32825344 11-11 22:53:42.357: D/memalloc(17856): /dev/pmem: Unmapping buffer base:0x5ecd3000 size:40361984 offset:36593664 11-11 22:53:42.367: D/memalloc(17856): /dev/pmem: Unmapping buffer base:0x61451000 size:7254016 offset:3485696 11-11 22:53:42.757: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x5c56d000 size:24621056 offset:20852736 fd:65 11-11 22:53:44.247: D/AndroidRuntime(17856): Shutting down VM 11-11 22:53:44.247: W/dalvikvm(17856): threadid=1: thread exiting with uncaught exception (group=0x40ac3210) 11-11 22:53:44.257: E/AndroidRuntime(17856): FATAL EXCEPTION: main 11-11 22:53:44.257: E/AndroidRuntime(17856): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{niall.shannon.timetable/niall.shannon.timetable.menu}: java.lang.NullPointerException 11-11 22:53:44.257: E/AndroidRuntime(17856): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1891) 11-11 22:53:44.257: E/AndroidRuntime(17856): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1992) 11-11 22:53:44.257: E/AndroidRuntime(17856): at android.app.ActivityThread.access$600(ActivityThread.java:127) 11-11 22:53:44.257: E/AndroidRuntime(17856): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1158) 11-11 22:53:44.257: E/AndroidRuntime(17856): at android.os.Handler.dispatchMessage(Handler.java:99) 11-11 22:53:44.257: E/AndroidRuntime(17856): at android.os.Looper.loop(Looper.java:137) 11-11 22:53:44.257: E/AndroidRuntime(17856): at android.app.ActivityThread.main(ActivityThread.java:4441) 11-11 22:53:44.257: E/AndroidRuntime(17856): at java.lang.reflect.Method.invokeNative(Native Method) 11-11 22:53:44.257: E/AndroidRuntime(17856): at java.lang.reflect.Method.invoke(Method.java:511) 11-11 22:53:44.257: E/AndroidRuntime(17856): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:823) 11-11 22:53:44.257: E/AndroidRuntime(17856): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:590) 11-11 22:53:44.257: E/AndroidRuntime(17856): at dalvik.system.NativeStart.main(Native Method) 11-11 22:53:44.257: E/AndroidRuntime(17856): Caused by: java.lang.NullPointerException 11-11 22:53:44.257: E/AndroidRuntime(17856): at android.content.ContextWrapper.openOrCreateDatabase(ContextWrapper.java:221) 11-11 22:53:44.257: E/AndroidRuntime(17856): at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:157) 11-11 22:53:44.257: E/AndroidRuntime(17856): at niall.shannon.timetable.DBAdapter.getClasses(DBAdapter.java:151) 11-11 22:53:44.257: E/AndroidRuntime(17856): at niall.shannon.timetable.menu.<init>(menu.java:15) 11-11 22:53:44.257: E/AndroidRuntime(17856): at java.lang.Class.newInstanceImpl(Native Method) 11-11 22:53:44.257: E/AndroidRuntime(17856): at java.lang.Class.newInstance(Class.java:1319) 11-11 22:53:44.257: E/AndroidRuntime(17856): at android.app.Instrumentation.newActivity(Instrumentation.java:1023) 11-11 22:53:44.257: E/AndroidRuntime(17856): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1882) 11-11 22:53:44.257: E/AndroidRuntime(17856): ... 11 more 11-11 22:53:46.527: I/Process(17856): Sending signal. PID: 17856 SIG: 9

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  • C++ Microsoft SAPI: How to set Windows text-to-speech output to a memory buffer?

    - by Vladimir
    Hi all, I have been trying to figure out how to "speak" a text into a memory buffer using Windows SAPI 5.1 but so far no success, even though it seems it should be quite simple. There is an example of streaming the synthesized speech into a .wav file, but no examples of how to stream it to a memory buffer. In the end I need to have the synthesized speech in a char* array in 16 kHz 16-bit little-endian PCM format. Currently I create a temp .wav file, redirect speech output there, then read it, but it seems to be a rather stupid solution. Anyone knows how to do that? Thanks!

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  • How do I write the audio stream to a memory buffer instead of a file using DirectShow?

    - by yngvedh
    Hi, I have made a sample application which constructs a filter graph to capture audio from the microphone and stream it to a file. Is there any filter which allows me to stream to a memory buffer instead? I'm following the approach outlined in an article on msdn and are currently using the CLSID_FileWriter object to write the audio to file. This works nicely, but I cannot figure out how to write to a memory buffer. Is there such a memory sink filter or do I have to create it myself? (I would prefer one which is bundled with windows XP)

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  • How to do inline paste from system buffer in Vim?

    - by yetapb
    When pasting from the system buffer in a line like foo( someVal , <cursor is here>, someVal3); If I use "*p I get foo( someVal, , someVal3); <pasted text> If I use "*P I get <pasted text> foo( someVal, , someVal3); but I want foo( someVal, <pasted text>, someVal3 ); How can I get the result I want? edit If there is a newline in the buffer as @amardeep suspects, is there a way I can tell vim to ignore it?

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  • how do i detect \r\n in a u_char type of buffer?

    - by aDi Adam
    i am trying to construct http content from packet sniffing in C. right now i am able to save all the packets in a file but i want to get rid of the headers in the first packet. they are also being saved as per they are a part of tcp payload. the actual body after the header starts after double "crlf" or \r\n\r\n in http response. how do i detect \r\n so that i can only save the following part of the buffer in the file. the buffer is u_char type. i cant figure out the command or the part i looked on google and other places but i mostly find c# commands, nothing in C.

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  • Difference between tcp recv buffer and tcp receive window size?

    - by pradeepchhetri
    The command shows the tcp receive buffer size in bytes. $ cat /proc/sys/net/ipv4/tcp_rmem 4096 87380 4001344 where the three values signifies the min, default and max values respectively. Then I tried to find the tcp window size using tcpdump command. $ sudo tcpdump -n -i eth0 'tcp[tcpflags] & (tcp-syn|tcp-ack) == tcp-syn and port 80 and host google.com' tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes 16:15:41.465037 IP 172.16.31.141.51614 > 74.125.236.73.80: Flags [S], seq 3661804272, win 14600, options [mss 1460,sackOK,TS val 4452053 ecr 0,nop,wscale 6], length 0 I got the window size to be 14600 which is 10 times the size of MSS. Can anyone please tell me the relationship between the two.

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  • SQL server could not connect: Lacked Sufficient Buffer Space...

    - by chumad
    I recently moved my app to a new server - the app is written in c# against the 3.5 framework. The hardware is faster but the OS is the same (Win Server 2003). No new software is running. On the prior hardware the app would run for months with no problems. Now, in this new install, I get the following error after about 3 days, and the only way to fix it is to reboot: A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: TCP Provider, error: 0 - An operation on a socket could not be performed because the system lacked sufficient buffer space or because a queue was full.) I have yet to find a service I can even shut down to make it work. Anyone had this before and know a solution?

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  • Problem on getting the vendor id and product id of a usb device

    - by new
    Hi... my application comes and prints this "\?\usb#vid_04f2&pid_0111#5&1ba5a77f&0&2#{a5dcbf1 0-6530-11d2-901f-00c04fb951ed}" again it goes to while loop .... here it gets breaked in the else statement... Qt Code: if (GetLastError() == ERROR_INSUFFICIENT_BUFFER) { // Change the buffer size. if (buffer) LocalFree(buffer); buffer = (LPTSTR)LocalAlloc(LPTR,buffersize); } else { qDebug ()<<"Here it quits the application"; // Insert error handling here. break; } Any ideas in this.... full source code comes here static GUID GUID_DEVINTERFACE_USB_DEVICE = { 0xA5DCBF10L, 0x6530, 0x11D2, { 0x90, 0x1F, 0x00, 0xC0, 0x4F, 0xB9, 0x51, 0xED } }; HANDLE hInfo = SetupDiGetClassDevs(&GUID_DEVINTERFACE_USB_DEVICE,NULL,NULL, DIGCF_PRESENT | DIGCF_INTERFACEDEVICE); if ( hInfo == INVALID_HANDLE_VALUE ) { qDebug ()<<"invalid"; } else { qDebug ()<<"valid handle"; SP_DEVINFO_DATA DeviceInfoData; DeviceInfoData.cbSize = sizeof(SP_DEVINFO_DATA); SP_INTERFACE_DEVICE_DATA Interface_Info; Interface_Info.cbSize = sizeof(Interface_Info); BYTE Buf[1024]; DWORD i; DWORD InterfaceNumber= 0; PSP_DEVICE_INTERFACE_DETAIL_DATA pspdidd = (PSP_DEVICE_INTERFACE_DETAIL_DATA) Buf; for (i=0;SetupDiEnumDeviceInfo(hInfo,i,&DeviceInfoData);i++) { DWORD DataT; LPTSTR buffer = NULL; DWORD buffersize = 0; while (!SetupDiGetDeviceRegistryProperty( hInfo, &DeviceInfoData,SPDRP_DEVICEDESC, &DataT,(PBYTE)buffer,buffersize, &buffersize)) { if (GetLastError() == ERROR_INSUFFICIENT_BUFFER) { // Change the buffer size. if (buffer) LocalFree(buffer); buffer = (LPTSTR)LocalAlloc(LPTR,buffersize); } else { // Insert error handling here. break; } qDebug ()<<(TEXT("Device Number %i is: %s\n"),i, buffer); if (buffer) LocalFree(buffer); if ( GetLastError() != NO_ERROR && GetLastError() != ERROR_NO_MORE_ITEMS ) { // Insert error handling here. qDebug ()<<"return false"; } InterfaceNumber = 0; // this just returns the first one, you can iterate on this if (SetupDiEnumDeviceInterfaces(hInfo, NULL, &GUID_DEVINTERFACE_USB_DEVICE, InterfaceNumber, &Interface_Info)) { printf("Got interface"); DWORD needed; pspdidd->cbSize = sizeof(*pspdidd); SP_DEVICE_INTERFACE_DETAIL_DATA *pDetData = NULL; DWORD dwDetDataSize = sizeof (SP_DEVICE_INTERFACE_DETAIL_DATA) + 256; pDetData = (SP_DEVICE_INTERFACE_DETAIL_DATA*) malloc (dwDetDataSize); pDetData->cbSize = sizeof (SP_DEVICE_INTERFACE_DETAIL_DATA); SetupDiGetDeviceInterfaceDetail(hInfo,&Interface_Info, pDetData,dwDetDataSize, NULL,&DeviceInfoData); qDebug ()<<pDetData->DevicePath; qDebug ()<<QString::fromWCharArray(pDetData->DevicePath); free(pDetData); } else { printf("\nNo interface"); //ErrorExit((LPTSTR) "SetupDiEnumDeviceInterfaces"); if ( GetLastError() == ERROR_NO_MORE_ITEMS) printf(", since there are no more items found."); else printf(", unknown reason."); } // Cleanup SetupDiDestroyDeviceInfoList(hInfo); } } }

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  • C# DirectSound - Capture buffers not continuous

    - by Wizche
    Hi, I'm trying to capture raw data from my line-in using DirectSound. My problem is that, from a buffer to another the data are just inconsistent, if for example I capture a sine I see a jump from my last buffer and the new one. To detected this I use a graph widget to draw the first 500 elements of the last buffer and the 500 elements from the new one: Snapshot I initialized my buffer this way: format = new WaveFormat { SamplesPerSecond = 44100, BitsPerSample = (short)bitpersample, Channels = (short)channels, FormatTag = WaveFormatTag.Pcm }; format.BlockAlign = (short)(format.Channels * (format.BitsPerSample / 8)); format.AverageBytesPerSecond = format.SamplesPerSecond * format.BlockAlign; _dwNotifySize = Math.Max(4096, format.AverageBytesPerSecond / 8); _dwNotifySize -= _dwNotifySize % format.BlockAlign; _dwCaptureBufferSize = NUM_BUFFERS * _dwNotifySize; // my capture buffer _dwOutputBufferSize = NUM_BUFFERS * _dwNotifySize / channels; // my output buffer I set my notifications one at half the buffer and one at the end: _resetEvent = new AutoResetEvent(false); _notify = new Notify(_dwCapBuffer); bpn1 = new BufferPositionNotify(); bpn1.Offset = ((_dwCapBuffer.Caps.BufferBytes) / 2) - 1; bpn1.EventNotifyHandle = _resetEvent.SafeWaitHandle.DangerousGetHandle(); bpn2 = new BufferPositionNotify(); bpn2.Offset = (_dwCapBuffer.Caps.BufferBytes) - 1; bpn2.EventNotifyHandle = _resetEvent.SafeWaitHandle.DangerousGetHandle(); _notify.SetNotificationPositions(new BufferPositionNotify[] { bpn1, bpn2 }); observer.updateSamplerStatus("Events listener initialization complete!\r\n"); And here is how I process the events. /* Process thread */ private void eventReceived() { int offset = 0; _dwCaptureThread = new Thread((ThreadStart)delegate { _dwCapBuffer.Start(true); while (isReady) { _resetEvent.WaitOne(); // Notification received /* Read the captured buffer */ Array read = _dwCapBuffer.Read(offset, typeof(short), LockFlag.None, _dwOutputBufferSize - 1); observer.updateTextPacket("Buffer: " + count.ToString() + " # " + read.GetValue(read.Length - 1).ToString() + " # " + read.GetValue(0).ToString() + "\r\n"); /* Print last/new part of the buffer to the debug graph */ short[] graphData = new short[1001]; Array.Copy(read, graphData, 1000); db.SetBufferDebug(graphData, 500); observer.updateGraph(db.getBufferDebug()); offset = (offset + _dwOutputBufferSize) % _dwCaptureBufferSize; /* Out buffer not used */ /*_dwDevBuffer.Write(0, read, LockFlag.EntireBuffer); _dwDevBuffer.SetCurrentPosition(0); _dwDevBuffer.Play(0, BufferPlayFlags.Default);*/ } _dwCapBuffer.Stop(); }); _dwCaptureThread.Start(); } Any advise? I'm sure I'm failing somewhere in the event processing, but I cant find where. I had developed the same application using the WaveIn API and it worked well. Thanks a lot...

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  • Some Async Socket Code - Help with Garbage Collection?

    - by divinci
    Hi all, I think this question is really about my understanding of Garbage collection and variable references. But I will go ahead and throw out some code for you to look at. // Please note do not use this code for async sockets, just to highlight my question // SocketTransport // This is a simple wrapper class that is used as the 'state' object // when performing Async Socket Reads/Writes public class SocketTransport { public Socket Socket; public byte[] Buffer; public SocketTransport(Socket socket, byte[] buffer) { this.Socket = socket; this.Buffer = buffer; } } // Entry point - creates a SocketTransport, then passes it as the state // object when Asyncly reading from the socket. public void ReadOne(Socket socket) { SocketTransport socketTransport_One = new SocketTransport(socket, new byte[10]); socketTransport_One.Socket.BeginRecieve ( socketTransport_One.Buffer, // Buffer to store data 0, // Buffer offset 10, // Read Length SocketFlags.None // SocketFlags new AsyncCallback(OnReadOne), // Callback when BeginRead completes socketTransport_One // 'state' object to pass to Callback. ); } public void OnReadOne(IAsyncResult ar) { SocketTransport socketTransport_One = ar.asyncState as SocketTransport; ProcessReadOneBuffer(socketTransport_One.Buffer); // Do processing // New Read // Create another! SocketTransport (what happens to first one?) SocketTransport socketTransport_Two = new SocketTransport(socket, new byte[10]); socketTransport_Two.Socket.BeginRecieve ( socketTransport_One.Buffer, 0, 10, SocketFlags.None new AsyncCallback(OnReadTwo), socketTransport_Two ); } public void OnReadTwo(IAsyncResult ar) { SocketTransport socketTransport_Two = ar.asyncState as SocketTransport; .............. So my question is: The first SocketTransport to be created (socketTransport_One) has a strong reference to a Socket object (lets call is ~SocketA~). Once the async read is completed, a new SocketTransport object is created (socketTransport_Two) also with a strong reference to ~SocketA~. Q1. Will socketTransport_One be collected by the garbage collector when method OnReadOne exits? Even though it still contains a strong reference to ~SocketA~ Thanks all!

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  • Working with a string as an array of characters

    - by Malfunction
    I'm having some trouble with a string represented as an array of characters. What I'd like to do, as I would do in java, is the following: while (i < chars.length) { char ch = chars[i]; if ((WORD_CHARS.indexOf(ch) >= 0) == punctuation) { String token = buffer.toString(); if (token.length() > 0) { parts.add(token); } buffer = new StringBuffer(); } buffer.append(ch); i++; } What I'm doing is something like this: while(i < strlen(chars)) { char ch = chars[i]; if(([WORD_CHARS rangeOfString:ch] >= 0) == punctuation) { NSString *token = buffer.toString(); if([token length] > 0) { [parts addObject:token]; } buffer = [NSMutableString string]; } [buffer append(ch)]; i++; } I'm not sure how I'm supposed to convert String token = buffer.toString(); to objective c, where buffer is an NSMutableString. Also, how do I check this if condition in objective c? if ((WORD_CHARS.indexOf(ch) >= 0) == punctuation) WORD_CHARS is an NSString. I'm also having trouble with appending ch to buffer. Any help is greatly appreciated.

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  • Coherence Warnings in WLS

    - by john.graves(at)oracle.com
    With 11g (10.3.4 WLS), coherence is now built into many applications.  I’ve been noticing errors in my OSB logs like these:####<10/03/2011 10:45:40 AM EST> <Warning> <Coherence> <osb-jeos> <osb_server1> <Logger@324239121 3.6.0.4> <<anonymous>> <> <583c1 0bfdbd326ba:-8c38159:12e9d02c829:-8000-0000000000000003> <1299714340643> <BEA-000000> <Oracle Coherence 3.6.0.4 (member=n/a): Unic astUdpSocket failed to set receive buffer size to 714 packets (1023KB); actual size is 12%, 89 packets (127KB). Consult your OS do cumentation regarding increasing the maximum socket buffer size. Proceeding with the actual value may cause sub-optimal performanc e.> ####<10/03/2011 10:45:40 AM EST> <Warning> <Coherence> <osb-jeos> <osb_server1> <Logger@324239121 3.6.0.4> <<anonymous>> <> <583c1 0bfdbd326ba:-8c38159:12e9d02c829:-8000-0000000000000003> <1299714340650> <BEA-000000> <Oracle Coherence 3.6.0.4 (member=n/a): Pref erredUnicastUdpSocket failed to set receive buffer size to 1428 packets (1.99MB); actual size is 6%, 89 packets (127KB). Consult y our OS documentation regarding increasing the maximum socket buffer size. Proceeding with the actual value may cause sub-optimal p erformance.> ####<10/03/2011 10:45:40 AM EST> <Warning> <Coherence> <osb-jeos> <osb_server1> <Logger@324239121 3.6.0.4> <<anonymous>> <> <583c1 0bfdbd326ba:-8c38159:12e9d02c829:-8000-0000000000000003> <1299714340659> <BEA-000000> <Oracle Coherence 3.6.0.4 (member=n/a): Mult icastUdpSocket failed to set receive buffer size to 714 packets (1023KB); actual size is 12%, 89 packets (127KB). Consult your OS documentation regarding increasing the maximum socket buffer size. Proceeding with the actual value may cause sub-optimal performa nce.> I was able to “fix” this on my ubuntu system by adding the following lines to the /etc/sysctl.conf file:# Setup networking for coherence # maximum receive socket buffer size, default 131071 net.core.rmem_max = 2000000 # maximum send socket buffer size, default 131071 net.core.wmem_max = 1000000 # default receive socket buffer size, default 65535 net.core.rmem_default = 2524287 # default send socket buffer size, default 65535 net.core.wmem_default = 2524287 .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }

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  • Triple buffering causes input lag?

    - by user782220
    Consider some time in between two vsyncs. Suppose the first display buffer is being used to display the current image, and suppose the game was really fast and computed and rendered the next image to the second display buffer and the next one after that to the third display buffer. That is the rendering to the second and third display buffer happens so fast that it occurs before the next vsync. Suppose input from the user comes in now. What you would like is for the results of the input to show up on the next vsync or (probably more typical) the vsync after that. However, with the third display buffer already rendered the input can only effect the image after that. Meaning the input will only take effect at best 3 vsyncs later. I wish i had an image to show the exact timings of what I mean.

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  • What utility is like Ten Clips, providing an enumerated clipboard?

    - by Aaron Newton
    A very useful (Windows) utility I use is TenClips - http://www.paludour.net/TenClips.html It allows you to create enumerated clipboards/emacs-like buffers easily using ctrl + f1, ctrl + f2, ctrl + f3, etc., copy to the clipboard in the first buffer, switch to the second buffer, copy without loosing our first buffer, switch back to the first buffer and paste, switch to the second buffer and paste and so forth. Does something like this exist for Ubuntu? The closest post I could find was Looking for an application that saves clipboard history which recommended Parcellite (http://parcellite.sourceforge.net/?page_id=2) - which keeps the history - but this is not quite what I'm after. If not I might make this a pet project :D

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  • Implementing a robust async stream reader

    - by Jon
    I recently provided an answer to this question: C# - Realtime console output redirection. As often happens, explaining stuff (here "stuff" was how I tackled a similar problem) leads you to greater understanding and/or, as is the case here, "oops" moments. I realized that my solution, as implemented, has a bug. The bug has little practical importance, but it has an extremely large importance to me as a developer: I can't rest easy knowing that my code has the potential to blow up. Squashing the bug is the purpose of this question. I apologize for the long intro, so let's get dirty. I wanted to build a class that allows me to receive input from a Stream in an event-based manner. The stream, in my scenario, is guaranteed to be a FileStream and there is also an associated StreamReader already present to leverage. The public interface of the class is this: public class MyStreamManager { public event EventHandler<ConsoleOutputReadEventArgs> StandardOutputRead; public void StartSendingEvents(); public void StopSendingEvents(); } Obviously this specific scenario has to do with a console's standard output, but that is a detail and does not play an important role. StartSendingEvents and StopSendingEvents do what they advertise; for the purposes of this discussion, we can assume that events are always being sent without loss of generality. The class uses these two fields internally: protected readonly StringBuilder inputAccumulator = new StringBuilder(); protected readonly byte[] buffer = new byte[256]; The functionality of the class is implemented in the methods below. To get the ball rolling: public void StartSendingEvents(); { this.stopAutomation = false; this.BeginReadAsync(); } To read data out of the Stream without blocking, and also without requiring a carriage return char, BeginRead is called: protected void BeginReadAsync() { if (!this.stopAutomation) { this.StandardOutput.BaseStream.BeginRead( this.buffer, 0, this.buffer.Length, this.ReadHappened, null); } } The challenging part: BeginRead requires using a buffer. This means that when reading from the stream, it is possible that the bytes available to read ("incoming chunk") are larger than the buffer. Since we are only handing off data from the stream to a consumer, and that consumer may well have inside knowledge about the size and/or format of these chunks, I want to call event subscribers exactly once for each chunk. Otherwise the abstraction breaks down and the subscribers have to buffer the incoming data and reconstruct the chunks themselves using said knowledge. This is much less convenient to the calling code, and detracts from the usefulness of my class. To this end, if the buffer is full after EndRead, we don't send its contents to subscribers immediately but instead append them to a StringBuilder. The contents of the StringBuilder are only sent back whenever there is no more to read from the stream (thus preserving the chunks). private void ReadHappened(IAsyncResult asyncResult) { var bytesRead = this.StandardOutput.BaseStream.EndRead(asyncResult); if (bytesRead == 0) { this.OnAutomationStopped(); return; } var input = this.StandardOutput.CurrentEncoding.GetString( this.buffer, 0, bytesRead); this.inputAccumulator.Append(input); if (bytesRead < this.buffer.Length) { this.OnInputRead(); // only send back if we 're sure we got it all } this.BeginReadAsync(); // continue "looping" with BeginRead } After any read which is not enough to fill the buffer, all accumulated data is sent to the subscribers: private void OnInputRead() { var handler = this.StandardOutputRead; if (handler == null) { return; } handler(this, new ConsoleOutputReadEventArgs(this.inputAccumulator.ToString())); this.inputAccumulator.Clear(); } (I know that as long as there are no subscribers the data gets accumulated forever. This is a deliberate decision). The good This scheme works almost perfectly: Async functionality without spawning any threads Very convenient to the calling code (just subscribe to an event) Maintains the "chunkiness" of the data; this allows the calling code to use inside knowledge of the data without doing any extra work Is almost agnostic to the buffer size (it will work correctly with any size buffer irrespective of the data being read) The bad That last almost is a very big one. Consider what happens when there is an incoming chunk with length exactly equal to the size of the buffer. The chunk will be read and buffered, but the event will not be triggered. This will be followed up by a BeginRead that expects to find more data belonging to the current chunk in order to send it back all in one piece, but... there will be no more data in the stream. In fact, as long as data is put into the stream in chunks with length exactly equal to the buffer size, the data will be buffered and the event will never be triggered. This scenario may be highly unlikely to occur in practice, especially since we can pick any number for the buffer size, but the problem is there. Solution? Unfortunately, after checking the available methods on FileStream and StreamReader, I can't find anything which lets me peek into the stream while also allowing async methods to be used on it. One "solution" would be to have a thread wait on a ManualResetEvent after the "buffer filled" condition is detected. If the event is not signaled (by the async callback) in a small amount of time, then more data from the stream will not be forthcoming and the data accumulated so far should be sent to subscribers. However, this introduces the need for another thread, requires thread synchronization, and is plain inelegant. Specifying a timeout for BeginRead would also suffice (call back into my code every now and then so I can check if there's data to be sent back; most of the time there will not be anything to do, so I expect the performance hit to be negligible). But it looks like timeouts are not supported in FileStream. Since I imagine that async calls with timeouts are an option in bare Win32, another approach might be to PInvoke the hell out of the problem. But this is also undesirable as it will introduce complexity and simply be a pain to code. Is there an elegant way to get around the problem? Thanks for being patient enough to read all of this.

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  • Thread Local Memory, Using std::string's internal buffer for c-style Scratch Memory.

    - by Hassan Syed
    I am using Protocol Buffers and OpensSSL to generate, HMACs and then CBC encrypt the two fields to obfuscate the session cookies -- similar Kerberos tokens. Protocol Buffers' API communicates with std::strings and has a buffer caching mechanism; I exploit the caching mechanism, for successive calls in the the same thread, by placing it in thread local memory; additionally the OpenSSL HMAC and EVP CTX's are also placed in the same thread local memory structure ( see this question for some detail on why I use thread local memory and the massive amount of speedup it enables even with a single thread). The generation and deserialization, "my algorithms", of these cookie strings uses intermediary void *s and std::strings and since Protocol Buffers has an internal memory retention mechanism I want these characteristics for "my algorithms". So how do I implement a common scratch memory ? I don't know much about the rdbuf(streambuf - strinbuf ??) of the std::string object. I would presumeably need to grow it to the lowest common size ever encountered during the execution of "my algorithms". Thoughts ? My question I guess would be: " is the internal buffer of a string re-usable, and if so, how ?" Edit: See comments to Vlad's answer please.

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  • Implementing a robust async stream reader for a console

    - by Jon
    I recently provided an answer to this question: C# - Realtime console output redirection. As often happens, explaining stuff (here "stuff" was how I tackled a similar problem) leads you to greater understanding and/or, as is the case here, "oops" moments. I realized that my solution, as implemented, has a bug. The bug has little practical importance, but it has an extremely large importance to me as a developer: I can't rest easy knowing that my code has the potential to blow up. Squashing the bug is the purpose of this question. I apologize for the long intro, so let's get dirty. I wanted to build a class that allows me to receive input from a Stream in an event-based manner. The stream, in my scenario, is guaranteed to be a FileStream and there is also an associated StreamReader already present to leverage. The public interface of the class is this: public class MyStreamManager { public event EventHandler<ConsoleOutputReadEventArgs> StandardOutputRead; public void StartSendingEvents(); public void StopSendingEvents(); } Obviously this specific scenario has to do with a console's standard output. StartSendingEvents and StopSendingEvents do what they advertise; for the purposes of this discussion, we can assume that events are always being sent without loss of generality. The class uses these two fields internally: protected readonly StringBuilder inputAccumulator = new StringBuilder(); protected readonly byte[] buffer = new byte[256]; The functionality of the class is implemented in the methods below. To get the ball rolling: public void StartSendingEvents(); { this.stopAutomation = false; this.BeginReadAsync(); } To read data out of the Stream without blocking, and also without requiring a carriage return char, BeginRead is called: protected void BeginReadAsync() { if (!this.stopAutomation) { this.StandardOutput.BaseStream.BeginRead( this.buffer, 0, this.buffer.Length, this.ReadHappened, null); } } The challenging part: BeginRead requires using a buffer. This means that when reading from the stream, it is possible that the bytes available to read ("incoming chunk") are larger than the buffer. Since we are only handing off data from the stream to a consumer, and that consumer may well have inside knowledge about the size and/or format of these chunks, I want to call event subscribers exactly once for each chunk. Otherwise the abstraction breaks down and the subscribers have to buffer the incoming data and reconstruct the chunks themselves using said knowledge. This is much less convenient to the calling code, and detracts from the usefulness of my class. Edit: There are comments below correctly stating that since the data is coming from a stream, there is absolutely nothing that the receiver can infer about the structure of the data unless it is fully prepared to parse it. What I am trying to do here is leverage the "flush the output" "structure" that the owner of the console imparts while writing on it. I am prepared to assume (better: allow my caller to have the option to assume) that the OS will pass me the data written between two flushes of the stream in exactly one piece. To this end, if the buffer is full after EndRead, we don't send its contents to subscribers immediately but instead append them to a StringBuilder. The contents of the StringBuilder are only sent back whenever there is no more to read from the stream (thus preserving the chunks). private void ReadHappened(IAsyncResult asyncResult) { var bytesRead = this.StandardOutput.BaseStream.EndRead(asyncResult); if (bytesRead == 0) { this.OnAutomationStopped(); return; } var input = this.StandardOutput.CurrentEncoding.GetString( this.buffer, 0, bytesRead); this.inputAccumulator.Append(input); if (bytesRead < this.buffer.Length) { this.OnInputRead(); // only send back if we 're sure we got it all } this.BeginReadAsync(); // continue "looping" with BeginRead } After any read which is not enough to fill the buffer, all accumulated data is sent to the subscribers: private void OnInputRead() { var handler = this.StandardOutputRead; if (handler == null) { return; } handler(this, new ConsoleOutputReadEventArgs(this.inputAccumulator.ToString())); this.inputAccumulator.Clear(); } (I know that as long as there are no subscribers the data gets accumulated forever. This is a deliberate decision). The good This scheme works almost perfectly: Async functionality without spawning any threads Very convenient to the calling code (just subscribe to an event) Maintains the "chunkiness" of the data; this allows the calling code to use inside knowledge of the data without doing any extra work Is almost agnostic to the buffer size (it will work correctly with any size buffer irrespective of the data being read) The bad That last almost is a very big one. Consider what happens when there is an incoming chunk with length exactly equal to the size of the buffer. The chunk will be read and buffered, but the event will not be triggered. This will be followed up by a BeginRead that expects to find more data belonging to the current chunk in order to send it back all in one piece, but... there will be no more data in the stream. In fact, as long as data is put into the stream in chunks with length exactly equal to the buffer size, the data will be buffered and the event will never be triggered. This scenario may be highly unlikely to occur in practice, especially since we can pick any number for the buffer size, but the problem is there. Solution? Unfortunately, after checking the available methods on FileStream and StreamReader, I can't find anything which lets me peek into the stream while also allowing async methods to be used on it. One "solution" would be to have a thread wait on a ManualResetEvent after the "buffer filled" condition is detected. If the event is not signaled (by the async callback) in a small amount of time, then more data from the stream will not be forthcoming and the data accumulated so far should be sent to subscribers. However, this introduces the need for another thread, requires thread synchronization, and is plain inelegant. Specifying a timeout for BeginRead would also suffice (call back into my code every now and then so I can check if there's data to be sent back; most of the time there will not be anything to do, so I expect the performance hit to be negligible). But it looks like timeouts are not supported in FileStream. Since I imagine that async calls with timeouts are an option in bare Win32, another approach might be to PInvoke the hell out of the problem. But this is also undesirable as it will introduce complexity and simply be a pain to code. Is there an elegant way to get around the problem? Thanks for being patient enough to read all of this.

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  • What would it take to get auto-revert-mode to actually work in my dired buffer?

    - by Cheeso
    Apparently auto-revert-mode is supposed to work in dired buffers. I had never heard of this, but the doc says it works. Then I read a little more and found some fine print: Auto-reverting Dired buffers currently works on GNU or Unix style operating systems. It may not work satisfactorily on some other systems. ...and... [dired buffers] do not auto-revert when information about a particular file changes (e.g. when the size changes) or when inserted subdirectories change. To be sure that all listed information is up to date, you have to manually revert using g, even if auto-reverting is enabled in the Dired buffer. source Well, uh, gee.... That doesn't sound like autorevert to me. What would it take to get auto-revert for dired to actually work? Even on (gasp) non-Unix operating systems. Could I just modify auto-revert-handler to call revert-buffer on dired buffers?

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