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  • Some general C questions.

    - by b-gen-jack-o-neill
    Hello. I am trying to fully understand the process pro writing code in some language to execution by OS. In my case, the language would be C and the OS would be Windows. So far, I read many different articles, but I am not sure, whether I understand the process right, and I would like to ask you if you know some good articles on some subjects I couldn´t find. So, what I think I know about C (and basically other languages): C compiler itself handles only data types, basic math operations, pointers operations, and work with functions. By work with functions I mean how to pass argument to it, and how to get output from function. During compilation, function call is replaced by passing arguments to stack, and than if function is not inline, its call is replaced by some symbol for linker. Linker than find the function definition, and replace the symbol to jump adress to that function (and of course than jump back to program). If the above is generally true and I get it right, where to final .exe file actually linker saves the functions? After the main() function? And what creates the .exe header? Compiler or Linker? Now, additional capabilities of C, today known as C standart library is set of functions and the declarations of them, that other programmers wrote to extend and simplify use of C language. But these functions like printf() were (or could be?) written in different language, or assembler. And there comes my next question, can be, for example printf() function be written in pure C without use of assembler? I know this is quite big question, but I just mostly want to know, wheather I am right or not. And trust me, I read a lots of articles on the web, and I would not ask you, If I could find these infromation together on one place, in one article. Insted I must piece by piece gather informations, so I am not sure if I am right. Thanks.

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  • iPhone UIView frame animation inconsistent why?

    - by Rick
    I have an app that uses an image loaded in from an UIImagePickerController instance. Once the picker is dismissed so as to reduce the jarring transition from the picker layout to the layout of the next function I initially have the UIImageView for the image fill the whole screen and then when the picker is dismissed the image 'squeezes' up to the top left of the screen. from the initWithFrame... targetPicView = [[UIImageView alloc] initWithFrame:CGRectMake(0.0, 0.0, 320.0, 480.0)]; [targetPicView setContentMode:UIViewContentModeScaleToFill]; this in a function called after dismissing the picker... [UIView beginAnimations:@"squeeze" context:context]; [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut]; [UIView setAnimationDuration:0.75]; [targetPicView setFrame:CGRectMake(20.0, 20.0, 130.0, 150.0)]; [UIView commitAnimations]; The weird thing is that this works great when the image has been chosen from the library, the view shrinks down with the top left corner in place just as I planned but... If the image comes from the camera then the view shrinks with the top right corner in place instead and appears to come in from the left side of the screen. Can anyone shed any light on this?

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  • Trying to use a authlogic-connect as a plugin in place of gem - Server doesn't start

    - by Arkid
    I am trying to use Authlogic-connect as a plugin in Rails 3 in place of a gem. I have made an entry in the gemfile as gem "authlogic-connect", :require => "authlogic-connect", :path => "localgems" Now when I run the bundle install, it runs fine. When I try to start the server i get the error Could not find gem 'authlogic-connect (>= 0, runtime)' in source at localgems. Source does not contain any versions of 'authlogic-connect (>= 0, runtime)' Try running `bundle install`. I have placed the unzipped Gem renamed as authlogic-connect in the localgems folder. what is the problem? Here is what I get on using rails plugin install arkidmitra$ rails plugin install git://github.com/viatropos/authlogic-connect.git Usage: rails new APP_PATH [options] Options: [--skip-gemfile] # Don't create a Gemfile -d, [--database=DATABASE] # Preconfigure for selected database (options: mysql/oracle/postgresql/sqlite3/frontbase/ibm_db) # Default: sqlite3 -O, [--skip-active-record] # Skip Active Record files [--dev] # Setup the application with Gemfile pointing to your Rails checkout -J, [--skip-prototype] # Skip Prototype files -T, [--skip-test-unit] # Skip Test::Unit files -G, [--skip-git] # Skip Git ignores and keeps -r, [--ruby=PATH] # Path to the Ruby binary of your choice # Default: /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby -m, [--template=TEMPLATE] # Path to an application template (can be a filesystem path or URL) -b, [--builder=BUILDER] # Path to an application builder (can be a filesystem path or URL) [--edge] # Setup the application with Gemfile pointing to Rails repository Runtime options: -q, [--quiet] # Supress status output -s, [--skip] # Skip files that already exist -f, [--force] # Overwrite files that already exist -p, [--pretend] # Run but do not make any changes Rails options: -h, [--help] # Show this help message and quit -v, [--version] # Show Rails version number and quit Description: The 'rails new' command creates a new Rails application with a default directory structure and configuration at the path you specify. Example: rails new ~/Code/Ruby/weblog This generates a skeletal Rails installation in ~/Code/Ruby/weblog. See the README in the newly created application to get going.

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  • SQL server deadlock between INSERT and SELECT statement

    - by dtroy
    Hi! I've got a problem with multiple deadlocks on SQL server 2005. This one is between an INSERT and a SELECT statement. There are two tables. Table 1 and Table2. Table2 has Table1's PK (table1_id) as foreign key. Index on table1_id is clustered. The INSERT inserts a single row into table2 at a time. The SELCET joins the 2 tables. (it's a long query which might take up to 12 secs to run) According to my understanding (and experiments) the INSERT should acquire an IS lock on table1 to check referential integrity (which should not cause a deadlock). But, in this case it acquired an IX page lock The deadlock report: <deadlock-list> <deadlock victim="process968898"> <process-list> <process id="process8db1f8" taskpriority="0" logused="2424" waitresource="OBJECT: 5:789577851:0 " waittime="12390" ownerId="61831512" transactionname="user_transaction" lasttranstarted="2010-04-16T07:10:13.347" XDES="0x222a8250" lockMode="IX" schedulerid="1" kpid="3764" status="suspended" spid="52" sbid="0" ecid="0" priority="0" transcount="2" lastbatchstarted="2010-04-16T07:10:13.350" lastbatchcompleted="2010-04-16T07:10:13.347" clientapp=".Net SqlClient Data Provider" hostname="VIDEV01-B-ME" hostpid="3040" loginname="DatabaseName" isolationlevel="read uncommitted (1)" xactid="61831512" currentdb="5" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128056"> <executionStack> <frame procname="DatabaseName.dbo.prcTable2_Insert" line="18" stmtstart="576" stmtend="1148" sqlhandle="0x0300050079e62d06e9307f000b9d00000100000000000000"> INSERT INTO dbo.Table2 ( f1, table1_id, f2 ) VALUES ( @p1, @p_DocumentVersionID, @p1 ) </frame> </executionStack> <inputbuf> Proc [Database Id = 5 Object Id = 103671417] </inputbuf> </process> <process id="process968898" taskpriority="0" logused="0" waitresource="PAGE: 5:1:46510" waittime="7625" ownerId="61831406" transactionname="INSERT" lasttranstarted="2010-04-16T07:10:12.717" XDES="0x418ec00" lockMode="S" schedulerid="2" kpid="1724" status="suspended" spid="53" sbid="0" ecid="0" priority="0" transcount="2" lastbatchstarted="2010-04-16T07:10:12.713" lastbatchcompleted="2010-04-16T07:10:12.713" clientapp=".Net SqlClient Data Provider" hostname="VIDEV01-B-ME" hostpid="3040" loginname="DatabaseName" isolationlevel="read committed (2)" xactid="61831406" currentdb="5" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128056"> <executionStack> <frame procname="DatabaseName.dbo.prcGetList" line="64" stmtstart="3548" stmtend="11570" sqlhandle="0x03000500dbcec17e8d267f000b9d00000100000000000000"> <!-- XXXXXXXXXXXXXX...SELECT STATEMENT WITH Multiple joins including both Table2 table 1 and .... XXXXXXXXXXXXXXX --> </frame> </executionStack> <inputbuf> Proc [Database Id = 5 Object Id = 2126630619] </inputbuf> </process> </process-list> <resource-list> <pagelock fileid="1" pageid="46510" dbid="5" objectname="DatabaseName.dbo.table1" id="lock6236bc0" mode="IX" associatedObjectId="72057594042908672"> <owner-list> <owner id="process8db1f8" mode="IX"/> </owner-list> <waiter-list> <waiter id="process968898" mode="S" requestType="wait"/> </waiter-list> </pagelock> <objectlock lockPartition="0" objid="789577851" subresource="FULL" dbid="5" objectname="DatabaseName.dbo.Table2" id="lock970a240" mode="S" associatedObjectId="789577851"> <owner-list> <owner id="process968898" mode="S"/> </owner-list> <waiter-list> <waiter id="process8db1f8" mode="IX" requestType="wait"/> </waiter-list> </objectlock> </resource-list> </deadlock> </deadlock-list> Can anyone explain why the INSERT gets the IX page lock ? Am I not reading the deadlock report properly? BTW, I have not managed to reproduce this issue. Thanks!

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  • Multiplication algorithm for abritrary precision (bignum) integers.

    - by nn
    Hi, I'm writing a small bignum library for a homework project. I am to implement Karatsuba multiplication, but before that I would like to write a naive multiplication routine. I'm following a guide written by Paul Zimmerman titled "Modern Computer Arithmetic" which is freely available online. On page 4, there is a description of an algorithm titled BasecaseMultiply which performs gradeschool multiplication. I understand step 2, 3, where B^j is a digit shift of 1, j times. But I don't understand step 1 and 3, where we have A*b_j. How is this multiplication meant to be carried out if the bignum multiplication hasn't been defined yet? Would the operation "*" in this algorithm just be the repeated addition method? Here is the parts I have written thus far. I have unit tested them so they appear to be correct for the most part: The structure I use for my bignum is as follows: #define BIGNUM_DIGITS 2048 typedef uint32_t u_hw; // halfword typedef uint64_t u_w; // word typedef struct { unsigned int sign; // 0 or 1 unsigned int n_digits; u_hw digits[BIGNUM_DIGITS]; } bn; Currently available routines: bn *bn_add(bn *a, bn *b); // returns a+b as a newly allocated bn void bn_lshift(bn *b, int d); // shifts d digits to the left, retains sign int bn_cmp(bn *a, bn *b); // returns 1 if a>b, 0 if a=b, -1 if a<b

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  • Automatically generating Regex from set of strings residing in DB C#

    - by Muhammad Adeel Zahid
    Hello Everyone i have about 100,000 strings in database and i want to if there is a way to automatically generate regex pattern from these strings. all of them are alphabetic strings and use set of alphabets from English letters. (X,W,V) is not used for example. is there any function or library that can help me achieve this target in C#. Example Strings are KHTK RAZ given these two strings my target is to generate a regex that allows patterns like (k, kh, kht,khtk, r, ra, raz ) case insensitive of course. i have downloaded and used some C# applications that help in generating regex but that is not useful in my scenario because i want a process in which i sequentially read strings from db and add rules to regex so this regex could be reused later in the application or saved on the disk. i m new to regex patterns and don't know if the thing i m asking is even possible or not. if it is not possible please suggest me some alternate approach. Any help and suggestions are highly appreciated. regards Adeel Zahid

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  • Netbeans and EOF

    - by sqlnoob
    Hey there, Java, ANTLR and Netbeans newbie here. I have installed a jdk and netbeans. I started a new project on netbeans 6.8 and i have added the antlr-3.2.jar as a library. I also created a lexer and parser class using AntlrWorks. These classes are named ExprParser.java and ExprLexer.java. I copied them into a directory named path-to-netbeans-project/src/parsers. I have a main file: package javaapplication2; import org.antlr.runtime.*; import parsers.*; public class Main { public static void main(String[] args) throws Exception{ ANTLRInputStream input = new ANTLRInputStream(System.in); ExprLexer lexer = new ExprLexer(input); CommonTokenStream tokens = new CommonTokenStream(lexer); ExprParser parser = new ExprParser(tokens); parser.prog(); } } The application builds fine. The book I'm reading says I should run the program and type in some stuff and then press Ctrl+Z (I'm on windows) to send EOF to the console. Problem is that nothing happens when I press Ctrl+z in the netbeans console. When I run from the command line, ctrl+z works fine. This is probably WAY too much information, but I can't figure it out. Sorry. Probably not a good idea to learn 3 new technologies at once.

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  • Service reference addition issue in visual studio 2010

    - by user293072
    I am currently working on an application that allows reverse geocoding using silverlight + bing maps. The thing is that I want to add a reference to the reverse geocoding service provided in msdn ( http://msdn.microsoft.com/en-us/library/cc879136.aspx) i.e. http:// dev.virtualearth.net/webservices/v1/geocodeservice/geocodeservice.svc?wsdl, but when I try to get a reference in vs2010, I get the following error: The document at the url http:// dev.virtualearth.net/webservices/v1/metadata/geocodeservice/geocodeservice.wsdl was not recognized as a known document type. The error message from each known type may help you fix the problem: Report from 'XML Schema' is ''', hexadecimal value 0x1F, is an invalid character. Line 1, position 1.'. Report from 'DISCO Document' is ''', hexadecimal value 0x1F, is an invalid character. Line 1, position 1.'. Report from 'WSDL Document' is 'There is an error in XML document (1, 1).'. '', hexadecimal value 0x1F, is an invalid character. Line 1, position 1. Metadata contains a reference that cannot be resolved: 'http://dev.virtualearth.net/webservices/v1/geocodeservice/geocodeservice.svc?wsdl'. Content Type application/soap+xml; charset=utf-8 was not supported by service http: //dev.virtualearth.net/webservices/v1/geocodeservice/geocodeservice.svc?wsdl. The client and service bindings may be mismatched. The remote server returned an error: (415) Unsupported Media Type. If the service is defined in the current solution, try building the solution and adding the service reference again. It is good to mention that I can access the service URL from the browser (with a no style information warning). I am aware that there are other reverse geolocoding services out there, but I am somewhat forced by certain circumstances to use only Microsoft-related components/services. Please help :)

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  • subsonic . navigate among records ,view,query

    - by gmo camilo
    hello everybody i'm some newbie in this matter of .net i'm trying understand this new paradigm i began with linq for SQl but i found this library, kind of framework of T4 more specifically: subsonic T4 i think it could be very usefull but the support docs outside are very scarce my first intention is use them in the very simple form: a catalog lets say... Users so... how can i use the model generated with subsonic ( using the iactiverecord) to implement the record-navigational part.,...???!!! i mean i want a simple form to create, delete or modify records and that is fairy easy but what about to move among records ? i found how to get the first, the last record.. but how can i advance or go back among them??? how can i order the records..? it seems everytime imust query the table.. its so? but how can imove among the records i already got? all of the exmples found are very simple dont touch the matter and/ or are repetitive everywhere so.. please if anybody can help me or give more references... i'd thank you a lot gmo camilo

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  • Make WebStart Java desktop application to start on system startup on Windows and Mac

    - by parxier
    I developed small cross-platform (Windows and Mac) SWT desktop application. It is distributed with WebStart. So far so good, everything works. I've got a new requirement to make my app start on system startup (with no user interaction). What is the best way to accomplish that? In JNLP file I've got this: <shortcut online="false"> <desktop/> <menu submenu="CompanyName"/> </shortcut> On Windows WebStart creates a desktop link [app_name].lnk and it points to javaws.exe and then some Java cache file as a parameter with funny name like ..\Sun\Java\Deployment\cache\6.0\4\2c0a6a781-213476. I can possibly programmatically find that link on user's machine by name... erm... and then copy it into user's Startup folder. I can see a problem here though as user can disable WebStart desktop shortcut creation option all together. On Mac WebStart pops up a dialog to prompt user for the location where to create an [app_name].app (user is allowed to change link name there!) file that launches an application. On Mac I don't event know where the Startup folder is located (and it seems to be much more complex there). Is there Java library out there that abstracts start app on system startup concept on different platforms as SWT does for GUI abstraction?

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  • Extending spring based app

    - by pitr
    I have a spring-based Web Service. I now want to build a sort of plugin for it that extends it with beans. What I have now in web.xml is: <context-param> <param-name>contextConfigLocation</param-name> <param-value>/WEB-INF/classes/*-configuration.xml</param-value> </context-param> My core app has main-configuration.xml which declares its beans. My plugin app has plugin-configuration.xml which declares additional beans. Now when I deploy, my build deploys plugin.jar into /WEB-INF/lib/ and copies plugin-configuration.xml into /WEB-INF/classes/ all under main.war. This is all fine (although I think there could be a better solution), but when I develop the plugin, I don't want to have two projects in Eclipse with dependencies. I wish to have main.jar that I include as a library. However, web.xml from main.jar isn't automatically discovered. How can I do this? Bean injection? Bean discovery of some sort? Something else? Note: I expect to have multiple different plugins in production, but development of each of them will be against pure main.jar Thank you.

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  • Symfony sfDoctrineGuard plugin sfGuardUser module

    - by Joe Mc
    When using sfDoctrineGuard plugin, it automatically generates the backend administration functionality where I can edit users of the system and assign them permissions. So I visit http://.../backend_dev.php/sf_guard_user/:id/edit where I am presented with the user's information including the available permissions to select. By default the permissions are shown as a multiple select box, HTML follows: <select name="sf_guard_user[permissions_list][]" multiple="multiple" id="sf_guard_user_permissions_list"> <option value="1">Permission1</option> <option value="2">Permission2</option> <option value="3">Permission3</option> <option value="4">Permission4</option> </select> What I would prefer is a list of checkboxes. So I searched around and found that if I add the option "expanded" set to true to the following code: 'permissions_list' => new sfWidgetFormDoctrineChoice(array('multiple' => true, 'model' => 'sfGuardPermission', 'expanded' => true,)), The code is part of this file: lib/form/doctrine/sfDoctrineGuardPlugin/base/BasesfGuardUserForm.class.php. I don't think I should've edited this file (potential for changes to be overwritten should sfDoctrineGuard ever be re-installed) but couldn't think of another way to make it work. The generated HTML is as follows: <ul class="checkbox_list"> <li><input name="sf_guard_user[permissions_list][]" type="checkbox" value="1" id="sf_guard_user_permissions_list_1" />&nbsp;<label for="sf_guard_user_permissions_list_1">Permission1</label></li> <li><input name="sf_guard_user[permissions_list][]" type="checkbox" value="2" id="sf_guard_user_permissions_list_2" />&nbsp;<label for="sf_guard_user_permissions_list_2">Permission2</label></li> <li><input name="sf_guard_user[permissions_list][]" type="checkbox" value="3" id="sf_guard_user_permissions_list_3" />&nbsp;<label for="sf_guard_user_permissions_list_3">Permission3</label></li> <li><input name="sf_guard_user[permissions_list][]" type="checkbox" value="4" id="sf_guard_user_permissions_list_4" />&nbsp;<label for="sf_guard_user_permissions_list_4">Permission4</label></li> </ul> What I need to do now is split up the permissions based on their prefix. For example if I had permissions named user_action1, user_action2, file_action1, file_action2, they would display like: User checkbox (custom label) Action One checkbox Action Two File checkbox (custom label) Action One checkbox Action Two but have no idea where to start with this. It would be easy if there was a template to edit but since I'm dealing with the Forms framework it is my understanding that the templates are generated on the fly - I can see them in my symonfy cache folder. How would I go about this? I started writing my own sfWidgetFormDoctrineChoicePermission class that extends the same class as sfWidgetFormDoctrineChoice but am struggling to edit the rendering functions correctly for the desired output. Is this the correct way to go about this work? I also need to integrate my sfGuardUserProfile model into the edit user page (same as above), I read somwhere that editing the generator.yml file for the sfGuardUser plugin module and simply adding the field names from the sfGuardUserProfile table would make it work, but sadly it doesn't. Any help with any of my queries would be appreciated. Thanks

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  • Mac OS X software always order files alphabetically rather than by type.

    - by george
    I have noticed many Mac applications sort the files alphabetically rather than by type. A good example would be Coda by panic.com. The files in the file menu are organized alphabetically. I requested for them to add the feature to organize files by type, and they've said that it's a Finder thing. So I looked at other applications to see if they were organizing by type. I noticed Dreamweaver CS4 had this same problem and now including Dreamweaver CS5. There has to be something in the Mac that does this and that I can modify. I played with Spotlight and it now displays its files by type (thinking that's what I can do) but it didn't take effect in other applications. What library are these applications using to display a file menu for their files? here is an example-- file menu layout of coda by panic.com. (i couldnt post another link because it wouldnt let me). can you see how everything is organised alphabetically rather than by folder? i just want the file menu to show all folders first then all the files. 1) http://www.iaddesign.com/coda.png there must be a way to modify mac to let me to do this.

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  • How should I go about implementing a points-to analysis in Maude?

    - by reprogrammer
    I'm going to implement a points-to analysis algorithm. I'd like to implement this analysis mainly based on the algorithm by Whaley and Lam. Whaley and Lam use a BDD based implementation of Datalog to represent and compute the points-to analysis relations. The following lists some of the relations that are used in a typical points-to analysis. Note that D(w, z) :- A(w, x),B(x, y), C(y, z) means D(w, z) is true if A(w, x), B(x, y), and C(y, z) are all true. BDD is the data structure used to represent these relations. Relations input vP0 (variable : V, heap : H) input store (base : V, field : F, source : V) input load (base : V, field : F, dest : V) input assign (dest : V, source : V) output vP (variable : V, heap : H) output hP (base : H, field : F, target : H) Rules vP(v, h) :- vP0(v, h) vP(v1, h) :- assign(v1, v2), vP(v2, h) hP(h1, f,h2) :- store(v1, f, v2), vP(v1, h1), vP(v2, h2) vP(v2, h2) :- load(v1, f, v2), vP(v1, h1), hP(h1, f, h2) I need to understand if Maude is a good environment for implementing points-to analysis. I noticed that Maude uses a BDD library called BuDDy. But, it looks like that Maude uses BDDs for a different purpose, i.e. unification. So, I thought I might be able to use Maude instead of a Datalog engine to compute the relations of my points-to analysis. I assume Maude propagates independent information concurrently. And this concurrency could potentially make my points-to analysis faster than sequential processing of rules. But, I don't know the best way to represent my relations in Maude. Should I implement BDD in Maude myself, or Maude's internal unification based on BDD has the same effect?

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  • call/cc in Lua - Possible?

    - by Pessimist
    The Wikipedia article on Continuation says: "In any language which supports closures, it is possible to write programs in continuation passing style and manually implement call/cc." Either that is true and I need to know how to do it or it is not true and that statement needs to be corrected. If this is true, please show me how to implement call/cc in Lua because I can't see how. I think I'd be able to implement call/cc manually if Lua had the coroutine.clone function as explained here. If closures are not enough to implement call/cc then what else is needed? The text below is optional reading. P.S.: Lua has one-shot continuations with its coroutine table. A coroutine.clone function would allow me to clone it to call it multiple times, thus effectively making call/cc possible (unless I misunderstand call/cc). However that cloning function doesn't exist in Lua. Someone on the Lua IRC channel suggested that I use the Pluto library (it implements serialization) to marshal a coroutine, copy it and then unmarshal it and use it again. While that would probably work, I am more interested in the theoretical implementation of call/cc and in finding what is the actual minimum set of features that a language needs to have in order to allow for its manual implementation.

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  • Writing to a log4net FileAppender with multiple threads performance problems

    - by Wayne
    TickZoom is a very high performance app which uses it's own parallelization library and multiple O/S threads for smooth utilization of multi-core computers. The app hits a bottleneck where users need to write information to a LogAppender from separate O/S threads. The FileAppender uses the MinimalLock feature so that each thread can lock and write to the file and then release it for the next thread to write. If MinimalLock gets disabled, log4net reports errors about the file being already locked by another process (thread). A better way for log4net to do this would be to have a single thread that takes care of writing to the FileAppender and any other threads simply add their messages to a queue. In that way, MinimalLock could be disabled to greatly improve performance of logging. Additionally, the application does a lot of CPU intensive work so it will also improve performance to use a separate thread for writing to the file so the CPU never waits on the I/O to complete. So the question is, does log4net already offer this feature? If so, how do you do enable threaded writing to a file? Is there another, more advanced appender, perhaps? If not, then since log4net is already wrapped in the platform, that makes it possible to implement a separate thread and queue for this purpose in the TickZoom code. Sincerely, Wayne

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  • record output sound in python

    - by aaronstacy
    i want to programatically record sound coming out of my laptop in python. i found PyAudio and came up with the following program that accomplishes the task: import pyaudio, wave, sys chunk = 1024 FORMAT = pyaudio.paInt16 CHANNELS = 1 RATE = 44100 RECORD_SECONDS = 5 WAVE_OUTPUT_FILENAME = sys.argv[1] p = pyaudio.PyAudio() channel_map = (0, 1) stream_info = pyaudio.PaMacCoreStreamInfo( flags = pyaudio.PaMacCoreStreamInfo.paMacCorePlayNice, channel_map = channel_map) stream = p.open(format = FORMAT, rate = RATE, input = True, input_host_api_specific_stream_info = stream_info, channels = CHANNELS) all = [] for i in range(0, RATE / chunk * RECORD_SECONDS): data = stream.read(chunk) all.append(data) stream.close() p.terminate() data = ''.join(all) wf = wave.open(WAVE_OUTPUT_FILENAME, 'wb') wf.setnchannels(CHANNELS) wf.setsampwidth(p.get_sample_size(FORMAT)) wf.setframerate(RATE) wf.writeframes(data) wf.close() the problem is i have to connect the headphone jack to the microphone jack. i tried replacing these lines: input = True, input_host_api_specific_stream_info = stream_info, with these: output = True, output_host_api_specific_stream_info = stream_info, but then i get this error: Traceback (most recent call last): File "./test.py", line 25, in data = stream.read(chunk) File "/Library/Python/2.5/site-packages/pyaudio.py", line 562, in read paCanNotReadFromAnOutputOnlyStream) IOError: [Errno Not input stream] -9975 is there a way to instantiate the PyAudio stream so that it inputs from the computer's output and i don't have to connect the headphone jack to the microphone? is there a better way to go about this? i'd prefer to stick w/ a python app and avoid cocoa.

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  • Rendering LaTeX on third-party websites

    - by A. Rex
    There are some sites on the web that render LaTeX into some more readable form, such as Wikipedia, some Wordpress blogs, and MathOverflow. They may use images, MathML, jsMath, or something like that. There are other sites on the web where LaTeX appears inline and is not rendered, such as the arXiv, various math forums, or my email. In fact, it is quite common to see an arXiv paper's abstract with raw LaTeX in it, e.g. this paper. Is there a plugin available for Firefox, or would it be possible to write one, that renders LaTeX within pages that do not provide a rendering mechanism themselves? Some notes: It may be impossible to render some of the code, because authors often copy-paste code directly from their source TeX files, which may contain things like "\cite{foo}" or undefined commands. These should be left alone. This question is a repost of a question from MathOverflow that was closed for not being related to math. I program a lot, but Javascript is not my specialty, so comments along the lines of "look at this library" are not particularly helpful to me (but may be to others).

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  • Encryption in Java & Flex

    - by Jef
    I want tp encrypt and decrypt string, with defined salt. But the result must be same if the code run in java and adobe flex. The main goal is: the app in adobe flex will be generate a string that can be decrypt in server using java. I use this flex library http://crypto.hurlant.com/demo/ Try to 'Secret Key' Tab. I want to use AES Encryption, 'CBC' or 'PKCS5'. var k:String = "1234567890123456"; var kdata:ByteArray = Hex.toArray(k); var txt:String = "hello"; var data:ByteArray = Hex.toArray(Hex.fromString(txt));; var name:String = "simple-aes-cbc"; var pad:IPad =new PKCS5(); var mode:ICipher = Crypto.getCipher(name, kdata, pad); pad.setBlockSize(mode.getBlockSize()); mode.encrypt(data); encrypted.text=Hex.fromArray(data); trace(Hex.fromArray(data)); And here is the code in java String plaintext = "hello"; String key = "1234567890123456"; SecretKey keyspec = new SecretKeySpec(key.getBytes(), "AES"); Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding"); cipher.init(Cipher.ENCRYPT_MODE,keyspec); byte[] encrypted = cipher.doFinal(plaintext.getBytes()); BASE64Encoder base64 = new BASE64Encoder(); String encodedString = base64.encode(encrypted); System.out.println(encodedString); Why the result is not same? Can you guys provide the sample with the same result both of java and flex (encrypt and decrypt)? And if I want to change the paramater, for example, from cbc to ebc, which line that need to be changed? Thanks!

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  • Autodetect Presence of CSV Headers in a File

    - by banzaimonkey
    Short question: How do I automatically detect whether a CSV file has headers in the first row? Details: I've written a small CSV parsing engine that places the data into an object that I can access as (approximately) an in-memory database. The original code was written to parse third-party CSV with a predictable format, but I'd like to be able to use this code more generally. I'm trying to figure out a reliable way to automatically detect the presence of CSV headers, so the script can decide whether to use the first row of the CSV file as keys / column names or start parsing data immediately. Since all I need is a boolean test, I could easily specify an argument after inspecting the CSV file myself, but I'd rather not have to (go go automation). I imagine I'd have to parse the first 3 to ? rows of the CSV file and look for a pattern of some sort to compare against the headers. I'm having nightmares of three particularly bad cases in which: The headers include numeric data for some reason The first few rows (or large portions of the CSV) are null There headers and data look too similar to tell them apart If I can get a "best guess" and have the parser fail with an error or spit out a warning if it can't decide, that's OK. If this is something that's going to be tremendously expensive in terms of time or computation (and take more time than it's supposed to save me) I'll happily scrap the idea and go back to working on "important things". I'm working with PHP, but this strikes me as more of an algorithmic / computational question than something that's implementation-specific. If there's a simple algorithm I can use, great. If you can point me to some relevant theory / discussion, that'd be great, too. If there's a giant library that does natural language processing or 300 different kinds of parsing, I'm not interested.

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  • Is SHA-1 secure for password storage?

    - by Tgr
    Some people throw around remarks like "SHA-1 is broken" a lot, so I'm trying to understand what exactly that means. Let's assume I have a database of SHA-1 password hashes, and an attacker whith a state of the art SHA-1 breaking algorithm and a botnet with 100,000 machines gets access to it. (Having control over 100k home computers would mean they can do about 10^15 operations per second.) How much time would they need to find out the password of any one user? find out the password of a given user? find out the password of all users? find a way to log in as one of the users? find a way to log in as a specific user? How does that change if the passwords are salted? Does the method of salting (prefix, postfix, both, or something more complicated like xor-ing) matter? Here is my current understanding, after some googling. Please correct in the answers if I misunderstood something. If there is no salt, a rainbow attack will immediately find all passwords (except extremely long ones). If there is a sufficiently long random salt, the most effective way to find out the passwords is a brute force or dictionary attack. Neither collision nor preimage attacks are any help in finding out the actual password, so cryptographic attacks against SHA-1 are no help here. It doesn't even matter much what algorithm is used - one could even use MD5 or MD4 and the passwords would be just as safe (there is a slight difference because computing a SHA-1 hash is slower). To evaluate how safe "just as safe" is, let's assume that a single sha1 run takes 1000 operations and passwords contain uppercase, lowercase and digits (that is, 60 characters). That means the attacker can test 1015*60*60*24 / 1000 ~= 1017 potential password a day. For a brute force attack, that would mean testing all passwords up to 9 characters in 3 hours, up to 10 characters in a week, up to 11 characters in a year. (It takes 60 times as much for every additional character.) A dictionary attack is much, much faster (even an attacker with a single computer could pull it off in hours), but only finds weak passwords. To log in as a user, the attacker does not need to find out the exact password; it is enough to find a string that results in the same hash. This is called a first preimage attack. As far as I could find, there are no preimage attacks against SHA-1. (A bruteforce attack would take 2160 operations, which means our theoretical attacker would need 1030 years to pull it off. Limits of theoretical possibility are around 260 operations, at which the attack would take a few years.) There are preimage attacks against reduced versions of SHA-1 with negligible effect (for the reduced SHA-1 which uses 44 steps instead of 80, attack time is down from 2160 operations to 2157). There are collision attacks against SHA-1 which are well within theoretical possibility (the best I found brings the time down from 280 to 252), but those are useless against password hashes, even without salting. In short, storing passwords with SHA-1 seems perfectly safe. Did I miss something?

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  • Question about registering COM server and Add Reference to it in a C# project

    - by smwikipedia
    I build a COM server in raw C++, here is the procedure: (1) write an IDL file to define the interface and library. (2) use msidl.exe to compile the IDL file to necessary .h, .c, .tlb files. (3) implement the COM server in C++ and build a .dll file. (4) add the following registry entris: [HKEY_CLASSES_ROOT\RawComCarLib.ComCar.1\CurVer] @="RawComCarLib.ComCar.1" ;CLSID [HKEY_CLASSES_ROOT\CLSID{6CC26343-167B-4CF2-9EDF-99368A62E91C}] @="RawComCarLib.ComCar.1" [HKEY_CLASSES_ROOT\CLSID{6CC26343-167B-4CF2-9EDF-99368A62E91C}\InprocServer32] @="D:\com\Project01.dll" [HKEY_CLASSES_ROOT\CLSID{6CC26343-167B-4CF2-9EDF-99368A62E91C}\ProgID] @="RawComCarLib.ComCar.1" [HKEY_CLASSES_ROOT\CLSID{6CC26343-167B-4CF2-9EDF-99368A62E91C}\TypeLib] @="{E5C0EE8F-8806-4FE3-BC0E-3A56CFB38BEE}" ;TypeLib [HKEY_CLASSES_ROOT\TypeLib{E5C0EE8F-8806-4FE3-BC0E-3A56CFB38BEE}] [HKEY_CLASSES_ROOT\TypeLib{E5C0EE8F-8806-4FE3-BC0E-3A56CFB38BEE}\1.0] @="Car Server Type Lib" [HKEY_CLASSES_ROOT\TypeLib{E5C0EE8F-8806-4FE3-BC0E-3A56CFB38BEE}\1.0\0] [HKEY_CLASSES_ROOT\TypeLib{E5C0EE8F-8806-4FE3-BC0E-3A56CFB38BEE}\1.0\0\win32] @="D:\com\Project01.tlb" [HKEY_CLASSES_ROOT\TypeLib{E5C0EE8F-8806-4FE3-BC0E-3A56CFB38BEE}\1.0\FLAGS] @="0" [HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib{E5C0EE8F-8806-4FE3-BC0E-3A56CFB38BEE}\1.0\0\win32] @="C:\Windows\System32\msdatsrc.tlb" (5) I try to add reference to the COM by click the Add Reference in the C# project. (6) In the COM tab, I saw my "Car Server Type Lib", it's ok until now. I try to use the Object Browser to browse my COM lib, but the Visual Studio said "the following components could not be browsed", and I noticed that there's no new reference added to the list in the C# project Reference. I can use the tlbimp.exe to generate a interop.CarCom.dll, and then use the COM through this interop dll, but I want this interop assembly to be generated automatically when I just add reference to the COM. Could someone tell me what's wrong? Many thanks.

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  • ruby gem not found although it is installed

    - by Eimantas
    I found some similar problems here on SO, but none seem to match my case (sorry if I overlooked). Here's my problem: I installed oauth-plugin gem to ruby gems dir, but trying to use it in rails app tells me that it's not being found. Here's the output of relevant commands: Instalation % s gem install oauth-plugin Successfully installed oauth-plugin-0.3.14 1 gem installed Installing ri documentation for oauth-plugin-0.3.14... Installing RDoc documentation for oauth-plugin-0.3.14... gem which oauth-plugin output: % gem which oauth-plugin /usr/lib/ruby/gems/1.8/gems/oauth-plugin-0.3.14/lib/oauth-plugin.rb gem env output: % gem env RubyGems Environment: - RUBYGEMS VERSION: 1.3.6 - RUBY VERSION: 1.8.7 (2009-12-24 patchlevel 248) [i686-darwin10.2.0] - INSTALLATION DIRECTORY: /usr/lib/ruby/gems/1.8 - RUBY EXECUTABLE: /usr/bin/ruby - EXECUTABLE DIRECTORY: /usr/bin - RUBYGEMS PLATFORMS: - ruby - x86-darwin-10 - GEM PATHS: - /usr/lib/ruby/gems/1.8 - /Users/eimantas/.gem/ruby/1.8 - GEM CONFIGURATION: - :update_sources => true - :verbose => true - :benchmark => false - :backtrace => true - :bulk_threshold => 1000 - :gem => ["--no-ri", "--no-rdoc"] - :sources => ["http://gems.ruby.lt/", "http://rubygems.org/"] - REMOTE SOURCES: - http://gems.ruby.lt/ - http://rubygems.org/ Doing ls -l /usr/lib/ruby shows this: % ls -l /usr/lib/ruby lrwxr-xr-x 1 root wheel 76 Aug 14 2009 /usr/lib/ruby -> ../../System/Library/Frameworks/Ruby.framework/Versions/Current/usr/lib/ruby And the gem in question is in intended location. This is not a single gem that is not being found by rubygems (although it's located where it should be). Any guidance towards the solution is much appreciated.

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  • Long running stateful service in .NET

    - by Asaf R
    Hi, I need to create a service in .NET that maintains (inner) state in-memory, spawns multiple threads and is generally long-running. There are a lot options - Good-old Windows Service Windows Communication Services Windows Workflow Foundation I really don't know which to choose. Most of the functionality is in a library used by this service, so the service itself is rather simple. On one hand, it's important the service host is as close to "simply working" as possible, which excludes Windows Service. On the other hand, it's important that the service is not taken down by the host just because there's no external activity, which makes WCF kind o' "scary". As for WF, it's strongest selling point is the ability to create processes as, um..., workflows, which is something I don't need nor want. To sum it up, the plethora of Microsoft technologies got me a bit confused. I'd appreciate help regarding the pros and cons of each solution (or other's I've failed to mention) for the problem of a stateful, long running service in .NET Thanks, Asaf P.S., I'm using .NET 4. EDIT: What I mean by the host "simply working" is, for example, that the service I create be reactivated if it crashes. I guess the reason for this question is that I've created Windows Services in the past (I think it was in plain C++ with Win32 API), and I don't want to miss out on something simpler if there's is such as thing. Thanks for all the replies thus far! Asaf.

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  • (C#) Get index of current foreach iteration

    - by Graphain
    Hi, Is there some rare language construct I haven't encountered (like the few I've learned recently, some on Stack Overflow) in C# to get a value representing the current iteration of a foreach loop? For instance, I currently do something like this depending on the circumstances: int i=0; foreach (Object o in collection) { ... i++; } Answers: @bryansh: I am setting the class of an element in a view page based on the position in the list. I guess I could add a method that gets the CSSClass for the Objects I am iterating through but that almost feels like a violation of the interface of that class. @Brad Wilson: I really like that - I've often thought about something like that when using the ternary operator but never really given it enough thought. As a bit of food for thought it would be nice if you could do something similar to somehow add (generically to all IEnumerable objects) a handle on the enumerator to increment the value that an extension method returns i.e. inject a method into the IEnumerable interface that returns an iterationindex. Of course this would be blatant hacks and witchcraft... Cool though... @crucible: Awesome I totally forgot to check the LINQ methods. Hmm appears to be a terrible library implementation though. I don't see why people are downvoting you though. You'd expect the method to either use some sort of HashTable of indices or even another SQL call, not an O(N) iteration... (@Jonathan Holland yes you are right, expecting SQL was wrong) @Joseph Daigle: The difficulty is that I assume the foreach casting/retrieval is optimised more than my own code would be. @Jonathan Holland: Ah, cheers for explaining how it works and ha at firing someone for using it.

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