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• Processing potentially large STDIN data, more than once

  - by d11wtq

  I'd like to provide an accessor on a class that provides an NSInputStream for STDIN, which may be several hundred megabytes (or gigabytes, though unlikely, perhaps) of data. When I caller gets this NSInputStream it should be able to read from it without worrying about exhausting the data it contains. In other words, another block of code may request the NSInputStream and will expect to be able to read from it. Without first copying all of the data into an NSData object which (I assume) would cause memory exhaustion, what are my options for handling this? The returned NSInputStream does not have to be the same instance, it simply needs to provide the same data. The best I can come up with right now is to copy STDIN to a temporary file and then return NSInputStream instances using that file. Is this pretty much the only way to handle it? Is there anything I should be cautious of if I go the temporary file route?

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• Classes, constructor and pointer class members

  - by pocoa

  I'm a bit confused about the object references. Please check the examples below: class ListHandler { public: ListHandler(vector<int> &list); private: vector<int> list; } ListHandler::ListHandler(vector<int> &list) { this->list = list; } Here I would be wasting memory right? So the right one would be: class ListHandler { public: ListHandler(vector<int>* list); private: vector<int>* list; } ListHandler::ListHandler(vector<int>* list) { this->list = list; } ListHandler::~ListHandler() { delete list; }

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• C++ Access violation when calling dll function

  - by Manjoor

  I have a function definition in my VC++ Win32 DLL DEMO2_API void ProcessData(char* i_buff, unsigned short i_len, char* o_buf, unsigned *o_len, unsigned short *errorCode) { __describe (i_buff,&i_len,o_buf,o_len,errorCode); } This dll function is called by a c# application. When called, it generate access violation exception. After reasearching i found, the cause for my problem. http://social.msdn.microsoft.com/Forums/en-US/csharplanguage/thread/6e843243-baf4-4eb1-8a20-c691ad47762c But could not understand what exactly they are doinng in example code. Can someone explain it so me? And what would be P/Invoke signature in c# after externally allocating memory?

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• Which development Language is best suited to Network Inventory

  - by dastardlyandmuttley

  Dear stackoverflow I hope this is the corrcet type of question for stackoverflow to consider I would like to develop a "Hard Core" application that performs Network Inventory. High level requirements are Work on Windows and UNIX networks it has to be extremly performant it has to be 100% accuarate (massively) scalable and fun to write The sort of details I am after is manufacturer and versions of all major workstation hardware components such as motherboard, network card, sound card, hard drives, optical drives, memory, BIOS details, operating system information etc. I dont want to have to distribute a client on each workstation to collect the information although i will require automatic worksattion discovery I would value your thoughts on the best development language to employ I know there are products such as NEWT and stuff like nmap... I would like to do this type of technical programming myself "from scratch" Warm Regards DD

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• C++ Win32 Unhandled Exception Handler

  - by uray

  currently I used SetUnhandledExceptionFilter() to provide callback to get information when an unhandled exception was occurred, that callback will provides me with EXCEPTION_RECORD which provides ExceptionAddress. [1]what is actually ExceptionAddress is? does it the address of function / code that gives exception, or the memory address that some function tried to access? [2]is there any better mechanism that could give me better information when unhandled exception occured? (I can't use debug mode or add any code that affect runtime performance, since crash is rare and only on release build when code run as fast as possible) [3]is there any way for me to get several callstack address when unhandled exception occured. [4]suppose ExceptionAddress has address A, and I have DLL X loaded and executed at base address A-x, and some other DLL Y at A+y, is it good to assume that crash was PROBABLY caused by code on DLL X?

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• On Windows XP, programmatically set Pagefile to "No Paging File" on single c: drive

  - by NBPC77

  I'm trying to write a C#/.NET application that optimizes the hard drives for our XP workstations Set pagefile to "No paging file" Reboot Run a defrag utility to optimize the data and apps Create a contiguous page file Reboot, run pagedefrag from Sysinternals I'm really struggling with #1. I delete the following key: SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\PagingFiles Upon reboot, the System Control Panel shows "No page file", but c:\pagefile.sys still exists and its in use by the SYSTEM process so I can't delete it and I can't optimize HD. I tried using PendingFileRenamingOperations and that bombs out too. I tried using WMI: Win32_PageFileSetting, but that only lets you set sizes (not zero--defaults to 2MB). Of course, if I do the manual steps outlined above, it works. I think I need an API call to make this happen.

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• Is there a faster alternative to using textures in XNA?

  - by Matthew Bowen

  I am writing a map editing program for a 2D game using XNA. To create a Texture2D for all of the tiles that a map requires takes too long. Are there any alternatives to using textures for drawing with XNA? I attempted to create just one texture per tile set instead of a texture for every tile in a tile set, but there is a limit to the size of textures and I could not fit all the tiles of a tile set into one texture. Currently the program contains all the would-be textures in memory as Bitmap objects. Is there a way to simply draw a Bitmap object to the screen in XNA? I have searched but I cannot find any information on this. This approach would avoid having to create textures altogether, however any tinting or effects I would have to do to the bitmap directly. Any help would be very much appreciated. Thanks

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• Problem with between join for sqlalchemy orm relation.

  - by Gary van der Merwe

  I'm trying to create a relation that has a between join. Here is a shortish example of what I'm trying to do: #!/usr/bin/env python import sqlalchemy as sa from sqlalchemy import orm from sqlalchemy.engine.base import Engine from sqlalchemy.ext.declarative import declarative_base metadata = sa.MetaData() Base = declarative_base(metadata=metadata) engine = sa.create_engine('sqlite:///:memory:') class Network(Base): __tablename__ = "network" id = sa.Column(sa.Integer, primary_key=True) ip_net_addr_db = sa.Column('ip_net_addr', sa.Integer, index=True) ip_broadcast_addr_db = sa.Column('ip_broadcast_addr', sa.Integer, index=True) # This can be determined from the net address and the net mask, but we store # it in the db so that we can join with the address table. ip_net_mask_len = sa.Column(sa.SmallInteger) class Address(Base): __tablename__ = "address" ip_addr_db = sa.Column('ip_addr', sa.Integer, primary_key=True, index=True, unique=True) Network.addresses = orm.relation(Address, primaryjoin=Address.ip_addr_db.between( Network.ip_net_addr_db, Network.ip_broadcast_addr_db), foreign_keys=[Address.ip_addr_db]) metadata.create_all(engine) Session = orm.sessionmaker(bind=engine) Network() I you run this, you get this error: ArgumentError: Could not determine relation direction for primaryjoin condition 'address.ip_addr BETWEEN network.ip_net_addr AND network.ip_broadcast_addr', on relation Network.addresses. Do the columns in 'foreign_keys' represent only the 'foreign' columns in this join condition ? The answer to that question is Yes, but I cant figure out how to tell it that

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• Light weight C++ SAX XML parser

  - by John Bartholomew

  I know of at least three light weight C++ XML parsers: RapidXML, TinyXML and PugiXML. However, all three use a DOM based interface (ie, they build their own in-memory representation of the XML document and then provide an interface to traverse and manipulate it). For most situations that I have to deal with, I much prefer the SAX interface (where the parser just spits out a stream of events like start-of-tag, and the application code is responsible for doing whatever it wants based on those events). Can anyone recommend a light weight C++ XML library with a SAX interface? Edit: I should also note the Microsoft XmlLite library, which does use a SAX interface. Unfortunately, it's ruled out for me at the moment since as far as I know it's closed source and Windows only (please correct me if I'm wrong on this).

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• Why is it preferable to call a static method statically from within an instance of the method's clas

  - by javanix

  If I create an instance of a class in Java, why is it preferable to call a static method of that same class statically, rather than using this.method()? I get a warning from Eclipse when I try to call static method staticMethod() from within the custom class's constructor via this.staticMethod(). public MyClass() { this.staticMethod(); } vs public MyClass() { MyClass.staticMethod(); } Can anyone explain why this is a bad thing to do? It seems to me like the compiler should already have allocated an instance of the object, so statically allocating memory would be unneeded overhead.

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• Disabling Xdebug's dumping of caught exceptions

  - by nuqqsa

  By default Xdebug will dump any exception regardless of whether it is caught or not: try { throw new Exception(); } catch (Exception $e) { } echo 'life goes on'; With XDebug enabled and the default settings this piece of code will actually output something like the following (nicely formatted): ( ! ) Exception: in /test.php on line 3 Call Stack # Time Memory Function Location 1 0.0003 52596 {main}( ) ../test.php:0 life goes on Is it possible to disable this behaviour and have it dumping only the uncaught exceptions? Thanks in advance. UPDATE: I'm about to conclude that this is a bug, since xdebug.show_exception_trace is disabled by default yet it doesn't behave as expected (using Xdebug v2.0.5 with PHP 5.2.10 on Ubuntu 9.10).

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• Django as S3 proxy

  - by schneck

  Hi there, I extended a ModelAdmin with a custom field "Download file", which is a link to a URL in my Django project, like: http://www.myproject.com/downloads/1 There, I want to serve a file which is stored in a S3-bucket. The files in the bucket are not public readable, and the user may not have direct access to it. Now I want to avoid that the file has to be loaded in the server memory (these are multi-gb-files) avoid to have temp files on the server The ideal solution would be to let django act as a proxy that streams S3-chunks directly to the user. I use boto, but did not find a possibility to stream the chunks. Any ideas? Thanks.

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• Why Read In UTF-16LE File Won't Convert "\r\n" Into "\n" In Windows

  - by Dbger

  I am using Perl to read UTF-16LE files in Windows 7. If I read in an ascii file with following code: open CUR_FILE, "<", $asciiFile; Then each "\r\n" in file will be converted into a "\n" in memory; if I read in an UTF-16LE(windows 1200) file with following code: open CUR_FILE, "<:encoding(UTF-16LE)", $utf16leFile; Then "\r\n" will keep unchanged. This inconsistency cause problems when I trying to regexp lines with line breaks. My questions is: Is this how unicode works in Perl & Windows? Or Am I using the wrong code? Thanks so much!

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• Tomcat - virtualhosting - name / ip / port - based

  - by lisak

  Hey, what are the usage scenarios for these kinds of virtual hosting ? Name Based - typical tomcat virtual hosting, one HOME instance with many contexts, each as an individual host IP based / port based - multiple instances of tomcat ( how is it with performance and memory consuption?) running on IP aliases (virtual IPs) for one network adapter, usually behind http apache server that can run name based virtual hostings. Otherwise I can't figure out how would I forward requests in iptables/firewall based on IP address, which is just one. How is IP based virtual hosting done as to Tomcat and multiple instances ? I'd like to hear some usage scenarios from your experience. How are you running your applications. Cause there are applications having it's own modified classloader and they are developed in a way to run alone withing a tomcat instance. Then there are trivial applications which can run within one instance without problems. Many thanks

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• GPU YUV to RGB. Worth the effort?

  - by Jaime Pardos

  Hello, I have to convert several full PAL videos (720x576@25) from YUV 4:2:2 to RGB, in real time, and probably a custom resize for each. I have thought of using the GPU, as I have seen some example that does just this (except that it's 4:4:4 so the bpp is the same in source and destiny)-- http://www.fourcc.org/source/YUV420P-OpenGL-GLSLang.c However, I don't have any experience with using GPU's and I'm not sure of what can be done. The example, as I understand it, just converts the video frame to YUV and displays it in the screen. Is it possible to get the processed frame instead? Would it be worth the effort to send it to the GPU, get it transformed, and sending it again to main memory, or would it kill performance? Being a bit platform-specific, assuming I work on windows, is it possible to get an OpenGL or DirectDraw surface from a window so the GPU can draw directly to it?

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• PHP website Optimization

  - by ana

  I have a high traffic website and I need make sure my site is fast enough to display my pages to everyone rapidly. I searched on Google many articles about speed and optimization and here's what I found: Cache the page Save it to the disk Caching the page in memory: This is very fast but if I need to change the content of my page I have to remove it from cache and then re-save the file on the disk. Save it to disk This is very easy to maintain but every time the page is accessed I have to read on the disk. Which method should I go with? Thanks

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• how to match a regulas expresion like (%i1) in python pexpect

  - by mike

  I want to use maxima from python using pexpect, whenever maxima starts it will print a bunch of stuff of this form: $ maxima Maxima 5.27.0 http://maxima.sourceforge.net using Lisp SBCL 1.0.57-1.fc17 Distributed under the GNU Public License. See the file COPYING. Dedicated to the memory of William Schelter. The function bug_report() provides bug reporting information. (%i1) i would like to start up pexpect like so: import pexpect cmd = 'maxima' child = pexpect.spawn(cmd) child.expect (' match all that stuff up to and including (%i1)') child.sendline ('integrate(sin(x),x)') chil.expect( match (%o1 ) ) print child.before how do i match the starting banner up to the prompt (%i1)? and so on, also maxima increments the (%i1)'s by one as the session goes along, so the next expect would be: child.expect ('match (%i2)') child.sendline ('integrate(sin(x),x)') chil.expect( match (%o2 ) ) print child.before how do i match the (incrementing) integers?

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• Dispelling the UIImage imageNamed: FUD

  - by Roger Nolan

  I see a lot of people saying imageNamed is bad but equal numbers of people saying the performance is good - especially when rendering UITableViews. See this SO question for example or this article on iPhoneDeveloperTips.com UIImage's imageNamed method used to leak so it was best avoided but has been fixed in recent releases. I'd like to understand the caching algorithm better in order to make a reasoned decision about where I can trust the system to cache my images and where I need to go the extra mile and do it myself. My current basic understanding is that it's a simple NSMutableDictionary of UIImages referenced by filename. It gets bigger and when memory runs out it gets a lot smaller. For example, does anyone know for sure that the image cache behind imageNamed does not respond to didReceiveMemoryWarning? It seems unlikely that Apple would not do this. If you have any insight into the caching algorithm, please post it here.

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• C# - Removing items from lists and all references to them.

  - by LiamV

  Hi there, I'm facing a situation where I have dependent objects and I would like to be able to remove an object and all references to it. Say I have an object structure like the code below, with a Branch type which references two Nodes. public class Node { // Has Some Data! } public class Branch { // Contains references to Nodes public Node NodeA public Node NodeB } public class Graph { public List<Node> Nodes; public List<Branch> Branches; } If I remove a Node from the Nodes list in the Graph class, it is still possible that one or more Branch objects still contains a reference to the removed Node, thus retaining it in memory, whereas really what I would quite like would be to set any references to the removed Node to null and let the garbage collection kick in. Other than enumerating through each Branch and checking each Node reference sequentially, are there any smart ideas on how I remove references to the Node in each Branch instance AND indeed any other class which reference the removed Node? Much appreciated, Liam

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• Advantage of using a static member function instead of an equivalent non-static member function?

  - by jonathanasdf

  I was wondering whether there's any advantages to using a static member function when there is a non-static equivalent. Will it result in faster execution (because of not having to care about all of the member variables), or maybe less use of memory (because of not being included in all instances)? Basically, the function I'm looking at is an utility function to rotate an integer array representing pixel colours an arbitrary number of degrees around an arbitrary centre point. It is placed in my abstract Bullet base class, since only the bullets will be using it and I didn't want the overhead of calling it in some utility class. It's a bit too long and used in every single derived bullet class, making it probably not a good idea to inline. How would you suggest I define this function? As a static member function of Bullet, of a non-static member function of Bullet, or maybe not as a member of Bullet but defined outside of the class in Bullet.h? What are the advantages and disadvantages of each?

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• Trouble with using ActiveX control in .net windows application

  - by alex dee

  C#, visual studio 2005 I have several 3rd party activeX control. I need to use them in my .net windows application. These controls are graphical. I created a wrapper with aximp.exe for them. But it seems that something wrong. When I call some methods of wrapped activeX control == targetinvocativeexception occured. Or visual studio writes "you are attempting to write or read protected memory". I know that something wrong. But what is exactly wrong - i don't know. I find out about method CreateControl() or STAthread attribute. but it doesn't help me. What is the common problem and common solution for my type of problem ? These activex control from big and trusted company, other developers work with them.

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• Why doesn't Maven's mvn clean ever work the first time?

  - by hoffmandirt

  Nine times out of ten when I run mvn clean on my projects I experience a build error. I have to execute mvn clean multiple times until the build error goes away. Does anyone else experience this? Is there any way to fix this within Maven? If not, how do you get around it? I wrote a bat file that deletes the target folders and that works well, but it's not practical when you are working on multiple projects. I am using Maven 2.2.1. [ERROR] BUILD ERROR [INFO] ------------------------------------------------------------------------ [INFO] Failed to delete directory: C:\Documents and Settings\user\My Documents\software-developm ent\a\b\c\application-domain\target. Reason: Unable to delete directory C:\Documen ts and Settings\user\My Documents\software-development\a\b\c\application-domai n\target\classes\com\a\b [INFO] ------------------------------------------------------------------------ [INFO] For more information, run Maven with the -e switch [INFO] ------------------------------------------------------------------------ [INFO] Total time: 6 seconds [INFO] Finished at: Fri Oct 23 15:22:48 EDT 2009 [INFO] Final Memory: 11M/254M [INFO] ------------------------------------------------------------------------

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• LINQ to SQL SubmitChangess() progress

  - by Emir

  I'm using LINQ to SQLto import old DBF files into MSSQL. I'm reading all rows and adding them to database using ctx.MyTable.InsertOnSubmit(row) After reading phase is completed I have around 100 000 pending inserts. ctx.SubmitChanges() naturally is taking a long time. Is there any way to track progress of the ctx.submitchanges()? Can ctx.Log somehow be used for this purpose? Update: Is it possible to use ctx.GetChangeSet().Inserts.Count and track insert statements using the Log? Dividing ctx.SubmitChanges() into smaller chunks is not working for me, because I need transaction, all or nothing. Update 2: I've found nice class ActionTextWriter using which I will try to count inserts. http://damieng.com/blog/2008/07/30/linq-to-sql-log-to-debug-window-file-memory-or-multiple-writers

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• How do I edit an interface builder object programmatically?

  - by Evelyn

  I created a label using Interface Builder, and now I want to set the background color of the label using code instead of IB's color picker. (I want to do this so that I can define the color using RGB and eventually change the colorspace for the label.) I'm in cocoa. How do I edit the attributes of an IB object using code? My code looks like this: //.h file #import <UIKit/UIKit.h> @interface IBAppDelegate : NSObject { UILabel *label; } @property (nonatomic, retain) IBOutlet UILabel *label; @end //.m file #import "IBAppDelegate.h" @implementation IBAppDelegate @synthesize label; (memory stuff...) @end

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• Dereferencing pointers without pointing them at a variable

  - by Miguel

  I'm having trouble understanding how some pointers work. I always thought that when you created a pointer variable (p), you couldn't deference and assign (*p = value) unless you either malloc'd space for it (p = malloc(x)), or set it to the address of another variable (p = &a) However in this code, the first assignment works consistently, while the last one causes a segfault: typedef struct { int value; } test_struct; int main(void) { //This works int* colin; *colin = 5; //This never works test_struct* carter; carter->value = 5; } Why does the first one work when colin isn't pointing at any spare memory? And why does the 2nd never work? I'm writing this in C, but people with C++ knowledge should be able to answer this as well.

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