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• Which Table Should be Master and Child in Database Design

  - by Jason

  I am quickly learning the ins and outs of database design (something that, as of a week ago, was new to me), but I am running across some questions that don't seem immediately obvious, so I was hoping to get some clarification. The question I have right is about foreign keys. As part of my design, I have a Company table. Originally, I had included address information directly within the table, but, as I was hoping to achieve 3NF, I broke out the address information into its own table, Address. In order to maintain data integrity, I created a row in Company called "addressId" as an INT and the Address table has a corresponding addressId as its primary key. What I'm a little bit confused about (or what I want to make sure I'm doing correctly) is determining which table should be the master (referenced) table and which should be the child (referencing) table. When I originally set this up, I made the Address table the master and the Company the child. However, I now believe this is wrong due to the fact that there should be only one address per Company and, if a Company row is deleted, I would want the corresponding Address to be removed as well (CASCADE deletion). I may be approaching this completely wrong, so I would appreciate any good rules of thumb on how to best think about the relationship between tables when using foreign keys. Thanks!

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• Perl, regex, extract data from a line

  - by perlnoob

  Im trying to extract part of a line with perl use strict; use warnings; # Set path for my.txt and extract datadir my @myfile = "C:\backups\MySQL\my.txt"; my @datadir = ""; open READMYFILE, @myfile or die "Error, my.txt not found.\n"; while (<READMYFILE>) { # Read file and extract DataDir path if (/C:\backups/gi) { push @datadir, $_; } } # ensure the path was found print @datadir . " \n"; Basically at first im trying to set the location of the my.txt file. Next im trying to read it and pull part of the line with regex. The error Im getting is: Unrecognized escape \m passed through at 1130.pl line 17. I took a look at http://stackoverflow.com/questions/1040657/how-can-i-grab-multiple-lines-after-a-matching-line-in-perl to get an idea of how to read a file and match a line within it, however im not 100% sure I'm doing this right or in the best way. I also seem to produce the error: Error, my.txt not found. But the file does exist in the folder C:\backups\MySQL\

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• Can i use the open source rich text editor in my site ? what does this GNU do with that ?

  - by Shyju

  I want to use one rich text editor to one of my ASP page.I searched in internet and found that there are lot of open source items available like TinyMCE,FCK Editror,nice edit etc.. Can i put the same samples in my website.There is a GNU license associated with it.Can somebody interpret it for me to answer these questions 1 . Can i use it in my website without getting a permission from anyone ? 2 . Do i need maintain the same files always ? Can i make some customization and use it ? Customization is only the CSS changes its going to be. 3 . Do i need to put all the files as it is of the package which downloaded.because my download has samples which supports all languages. Do i need to put all those folders too From GNU license " if you distribute copies of such a program, whether gratis or for a fee, you must pass on to the recipients the same freedoms that you received. You must make sure that they, too, receive or can get the source code. And you must show them these terms so they know their rights."

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• Designing secure consumer blackberry application

  - by Kiran Kuppa

  I am evaluating a requirement for a consumer blackberry application that places high premium on security of user's data. Seems like it is an insurance company. Here are my ideas on how I could go about it. I am sure this would be useful for others who are looking for similar stuff Force the user to use device password. (I am guessing that this would be possible - though not checked it yet). Application can request notifications when the device is about to be locked and just after it has been unlocked. Encryption of application specific data can be managed at those times. Application data would be encrypted with user's password. User's credentials would be encrypted with device password. Remote backup of the data could be done over HTTPS (any better ideas are appreciated) Questions: What if the user forgets his device password. If the user forgets his application password, what is the best and secure way to reset the password? If the user losses the phone, remote backup must be done and the application data must be cleaned up. I have some ideas on how to achieve (3) and shall share them. There must be an off-line verification of the user's identity and the administrator must provide a channel using which the user must be able to send command to the device to perform the wiping of application data. The idea is that the user is ALWAYS in control of his data. Without the user's consent, even the admin must not be able to do activities such as cleaning up the data. In the above scheme of things, it appears as if the user's password need not be sent over the air to server. Am I correct? Thanks, --Kiran Kumar

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• Why do child elements cause 'dropleave' to be called (drag-n-drop file upload)?

  - by tundoopani

  I have a HTML5 drag-n-drop script that allows users to drop files in #droparea. The #droparea div has child elements that are also div elements. <div id="droparea"> <div id="showif_no_dragover">Drag files here!</div> <div id="showif_dragover">Drop the files!</div> </div> The associated javascript/jquery is: var droptarget = "#droparea"; $(droptarget).live('dragenter', dragEnter); $(droptarget).live('dragleave', dragExit); $(droptarget).live('dragover', nothing); $(droptarget).live('drop', dropGo); (Side question: should I use .live(), .on() or .bind() here?) I have created a sample jsFiddle with some additional code here: http://jsfiddle.net/PwFr9/3/ If you look at the console, you will notice that as you drag a file within #droparea, dragenter() and dragleave() are called multiple times, even though the drag is still inside #droparea. If you remove the child elements (#child1 and #child2), the problem is gone because the child elements are gone. How can I keep the child elements and prevent them from messing up the drag events? I have searched Stackoverflow and Google for hours without much help. I found this questions here at Stackoverflow: How to keep child elements from interfering with HTML5 dragover and drop events? I don't know why it works, though. I have tried placing 2 div elements on top of each other (via CSS positioning). The top-most div has the drag events attached whereas the bottom-most div has the child elements. I do not like this approach because it doesn't work with the rest of my page and does not allow mouse-click interaction with the bottom-most div. Any help is appreciated! Thank you in advance. Regards, tundoo

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• Use auto_ptr in VC6 dll cause crash

  - by Yan Cheng CHEOK

  // dll #include <memory> __declspec(dllexport) std::auto_ptr<int> get(); __declspec(dllexport) std::auto_ptr<int> get() { return std::auto_ptr<int>(new int()); } // exe #include <iostream> #include <memory> __declspec(dllimport) std::auto_ptr<int> get(); int main() { { std::auto_ptr<int> x = get(); } std::cout << "done\n"; getchar(); } The following code run perfectly OK under VC9. However, under VC6, I will experience an immediate crash with the following message. Debug Assertion Failed! Program: C:\Projects\use_dynamic_link\Debug\use_dynamic_link.exe File: dbgheap.c Line: 1044 Expression: _CrtIsValidHeapPointer(pUserData) Is it exporting auto_ptr under VC6 is not allowed? It is a known problem that exporting STL collection classes through DLL. http://stackoverflow.com/questions/2451714/access-violation-when-accessing-an-stl-object-through-a-pointer-or-reference-in-a However, I Google around and do not see anything mention for std::auto_ptr. Any workaround?

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• remove specific values from multi value dictionary

  - by Anthony

  I've seen posts here on how to make a dictionary that has multiple values per key, like one of the solutions presented in this link: Multi Value Dictionary it seems that I have to use a List< as the value for the keys, so that a key can store multiple values. the solution in the link is fine if you want to add values. But my problem now is how to remove specific values from a single key. I have this code for adding values to a dictionary: private Dictionary<TKey, List<TValue>> mEventDict; // this is for initializing the dictionary public void Subscribe(eVtEvtId inEvent, VtEvtDelegate inCallbackMethod) { if (mEventDict.ContainsKey(inEvent)) { mEventDict[inEvent].Add(inCallbackMethod); } else { mEventDict.Add(inEvent, new List<TValue>() { v }); } } // this is for adding values to the dictionary. // if the "key" (inEvent) is not yet present in the dictionary, // the key will be added first before the value my problem now is removing a specific value from a key. I have this code: public void Unsubscribe(eVtEvtId inEvent, VtEvtDelegate inCallbackMethod) { try { mEventDict[inEvent].Remove(inCallbackMethod); } catch (ArgumentNullException) { MessageBox.Show("The event is not yet present in the dictionary"); } } basically, what I did is just replace the Add() with Remove() . Will this work? Also, if you have any problems or questions with the code (initialization, etc.), feel free to ask. Thanks for the advice.

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• Cluster failover and strange gratuitous arp behavior

  - by lazerpld

  I am experiencing a strange Windows 2008R2 cluster related issue that is bothering me. I feel that I have come close as to what the issue is, but still don't fully understand what is happening. I have a two node exchange 2007 cluster running on two 2008R2 servers. The exchange cluster application works fine when running on the "primary" cluster node. The problem occurs when failing over the cluster ressource to the secondary node. When failing over the cluster to the "secondary" node, which for instance is on the same subnet as the "primary", the failover initially works ok and the cluster ressource continues to work for a couple of minutes on the new node. Which means that the recieving node does send out a gratuitous arp reply packet that updated the arp tables on the network. But after x amount of time (typically within 5 minutes time) something updates the arp-tables again because all of a sudden the cluster service does not answer to pings. So basically I start a ping to the exchange cluster address when its running on the "primary node". It works just great. I failover the cluster ressource group to the "secondary node" and I only have loss of one ping which is acceptable. The cluster ressource still answers for some time after being failed over and all of a sudden the ping starts timing out. This is telling me that the arp table initially is updated by the secondary node, but then something (which I haven't found out yet) wrongfully updates it again, probably with the primary node's MAC. Why does this happen - has anyone experienced the same problem? The cluster is NOT running NLB and the problem stops immidiately after failing over back to the primary node where there are no problems. Each node is using NIC teaming (intel) with ALB. Each node is on the same subnet and has gateway and so on entered correctly as far as I am concerned. Edit: I was wondering if it could be related to network binding order maybe? Because I have noticed that the only difference I can see from node to node is when showing the local arp table. On the "primary" node the arp table is generated on the cluster address as the source. While on the "secondary" its generated from the nodes own network card. Any input on this? Edit: Ok here is the connection layout. Cluster address: A.B.6.208/25 Exchange application address: A.B.6.212/25 Node A: 3 physical nics. Two teamed using intels teaming with the address A.B.6.210/25 called public The last one used for cluster traffic called private with 10.0.0.138/24 Node B: 3 physical nics. Two teamed using intels teaming with the address A.B.6.211/25 called public The last one used for cluster traffic called private with 10.0.0.139/24 Each node sits in a seperate datacenter connected together. End switches being cisco in DC1 and NEXUS 5000/2000 in DC2. Edit: I have been testing a little more. I have now created an empty application on the same cluster, and given it another ip address on the same subnet as the exchange application. After failing this empty application over, I see the exact same problem occuring. After one or two minutes clients on other subnets cannot ping the virtual ip of the application. But while clients on other subnets cannot, another server from another cluster on the same subnet has no trouble pinging. But if i then make another failover to the original state, then the situation is the opposite. So now clients on same subnet cannot, and on other they can. We have another cluster set up the same way and on the same subnet, with the same intel network cards, the same drivers and same teaming settings. Here we are not seeing this. So its somewhat confusing. Edit: OK done some more research. Removed the NIC teaming of the secondary node, since it didnt work anyway. After some standard problems following that, I finally managed to get it up and running again with the old NIC teaming settings on one single physical network card. Now I am not able to reproduce the problem described above. So it is somehow related to the teaming - maybe some kind of bug? Edit: Did some more failing over without being able to make it fail. So removing the NIC team looks like it was a workaround. Now I tried to reestablish the intel NIC teaming with ALB (as it was before) and i still cannot make it fail. This is annoying due to the fact that now i actually cannot pinpoint the root of the problem. Now it just seems to be some kind of MS/intel hick-up - which is hard to accept because what if the problem reoccurs in 14 days? There is a strange thing that happened though. After recreating the NIC team I was not able to rename the team to "PUBLIC" which the old team was called. So something has not been cleaned up in windows - although the server HAS been restarted! Edit: OK after restablishing the ALB teaming the error came back. So I am now going to do some thorough testing and i will get back with my observations. One thing is for sure. It is related to Intel 82575EB NICS, ALB and Gratuitous Arp.

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• why unsigned int 0xFFFFFFFF is equal to int -1?

  - by conejoroy

  perhaps it's a very stupid question but I'm having a hard time figuring this out =) in C or C++ it is said that the maximum number a size_t (an unsigned int data type) can hold is the same as casting -1 to that data type. for example see http://stackoverflow.com/questions/1420982/invalid-value-for-sizet Why?? I'm confused.. I mean, (talking about 32 bit ints) AFAIK the most significant bit holds the sign in a signed data type (that is, bit 0x80000000 to form a negative number). then, 1 is 0x00000001.. 0x7FFFFFFFF is the greatest positive number a int data type can hold. then, AFAIK the binary representation of -1 int should be 0x80000001 (perhaps I'm wrong). why/how this binary value is converted to anything completely different (0xFFFFFFFF) when casting ints to unsigned?? or.. how is it possible to form a binary -1 out of 0xFFFFFFFF? I have no doubt that in C: ((unsigned int)-1) == 0xFFFFFFFF or ((int)0xFFFFFFFF) == -1 is equally true than 1 + 1 == 2, I'm just wondering why. thanks!

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• ADO/SQL Server: What is the error code for "timeout expired"?

  - by Ian Boyd

  i'm trying to trap a "timeout expired" error from ADO. When a timeout happens, ADO returns: Number: 0x80040E31 (DB_E_ABORTLIMITREACHED in oledberr.h) SQLState: HYT00 NativeError: 0 The NativeError of zero makes sense, since the timeout is not a function of the database engine (i.e. SQL Server), but of ADO's internal timeout mechanism. The Number (i.e. the COM hresult) looks useful, but the definition of DB_E_ABORTLIMITREACHED in oledberr.h says: Execution stopped because a resource limit was reached. No results were returned. This error could apply to things besides "timeout expired" (some potentially server-side), such as a governor that limits: CPU usage I/O reads/writes network bandwidth and stops a query. The final useful piece is SQLState, which is a database-independent error code system. Unfortunately the only reference for SQLState error codes i can find have no mention of HYT00. What to do? What do do? Note: i can't trust 0x80040E31 (DB_E_ABORTLIMITREACHED) to mean "timeout expired", anymore than i could trust 0x80004005 (E_UNSPECIFIED_ERROR) to mean "Transaction was deadlocked on lock resources with another process and has been chosen as the deadlock victim". My pseudo-question becomes: does anyone have documentation on what the SQLState "HYT000" means? And my real question still remains: How can i specifically trap an ADO timeout expired exception thrown by ADO? Gotta love the questions where the developer is trying to "do the right thing", but nobody knows how to do the right thing. Also gotta love how googling for DB_E_ABORTLIMITREACHED and this question is #9, with MSDN nowhere to be found. Update 3 From the OLEdb ICommand.Execute reference: DB_E_ABORTLIMITREACHED Execution has been aborted because a resource limit has been reached. For example, a query timed out. No results have been returned. "For example", meaning not an exhaustive list.

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• Float a div in top right corner without overlapping sibling header

  - by Maxime R.

  Having a div and a h1 inside a section, how do i float the div in the top right corner without overlapping the text of the header ? The HTML code is the following: <section> <h1>some long long long long header, a whole line, 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6</h1> <div><button>button</button></div> </section> I tried an absolute position relative to the parent but the text is overlapped, http://jsfiddle.net/FnpS8/2/ Using this CSS code: section { position: relative; } h1 { display: inline; } div { position: absolute; top: 0; right: 0; } I tried floating the div to the right but it doesn't remain in the top right corner, http://jsfiddle.net/P6xCw/2/ Using this CSS code: h1 { display: inline; } div { float: right; } ? I know there is a lot of similar questions but I couldn't find one solving this case.

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• Django: Serving Media Behind Custom URL

  - by TheLizardKing

  So I of course know that serving static files through Django will send you straight to hell but I am confused on how to use a custom url to mask the true location of the file using Django. http://stackoverflow.com/questions/2681338/django-serving-a-download-in-a-generic-view but the answer I accepted seems to be the "wrong" way of doing things. urls.py: url(r'^song/(?P<song_id>\d+)/download/$', song_download, name='song_download'), views.py: def song_download(request, song_id): song = Song.objects.get(id=song_id) fsock = open(os.path.join(song.path, song.filename)) response = HttpResponse(fsock, mimetype='audio/mpeg') response['Content-Disposition'] = "attachment; filename=%s - %s.mp3" % (song.artist, song.title) return response This solution works perfectly but not perfectly enough it turns out. How can I avoid having a direct link to the mp3 while still serving through nginx/apache? EDIT 1 - ADDITIONAL INFO Currently I can get my files by using an address such as: http://www.example.com/music/song/1692/download/ But the above mentioned method is the devil's work. How can I accomplished what I get above while still making nginx/apache serve the media? Is this something that should be done at the webserver level? Some crazy mod_rewrite? http://static.example.com/music/Aphex%20Twin%20-%20Richard%20D.%20James%20(V0)/10%20Logon-Rock%20Witch.mp3

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• Have suggestions for these assembly mnemonics?

  - by Noctis Skytower

  Greetings! Last semester in college, my teacher in the Computer Languages class taught us the esoteric language named Whitespace. In the interest of learning the language better with a very busy schedule (midterms), I wrote an interpreter and assembler in Python. An assembly language was designed to facilitate writing programs easily, and a sample program was written with the given assembly mnemonics. Now that it is summer, a new project has begun with the objective being to rewrite the interpreter and assembler for Whitespace 0.3, with further developments coming afterwards. Since there is so much extra time than before to work on its design, you are presented here with an outline that provides a revised set of mnemonics for the assembly language. This post is marked as a wiki for their discussion. Have you ever had any experience with assembly languages in the past? Were there some instructions that you thought should have been renamed to something different? Did you find yourself thinking outside the box and with a different paradigm than in which the mnemonics were named? If you can answer yes to any of those questions, you are most welcome here. Subjective answers are appreciated! Stack Manipulation (IMP: [Space]) Stack manipulation is one of the more common operations, hence the shortness of the IMP [Space]. There are four stack instructions. hold N Push the number onto the stack copy Duplicate the top item on the stack copy N Copy the nth item on the stack (given by the argument) onto the top of the stack swap Swap the top two items on the stack drop Discard the top item on the stack drop N Slide n items off the stack, keeping the top item Arithmetic (IMP: [Tab][Space]) Arithmetic commands operate on the top two items on the stack, and replace them with the result of the operation. The first item pushed is considered to be left of the operator. add Addition sub Subtraction mul Multiplication div Integer Division mod Modulo Heap Access (IMP: [Tab][Tab]) Heap access commands look at the stack to find the address of items to be stored or retrieved. To store an item, push the address then the value and run the store command. To retrieve an item, push the address and run the retrieve command, which will place the value stored in the location at the top of the stack. save Store load Retrieve Flow Control (IMP: [LF]) Flow control operations are also common. Subroutines are marked by labels, as well as the targets of conditional and unconditional jumps, by which loops can be implemented. Programs must be ended by means of [LF][LF][LF] so that the interpreter can exit cleanly. L: Mark a location in the program call L Call a subroutine goto L Jump unconditionally to a label if=0 L Jump to a label if the top of the stack is zero if<0 L Jump to a label if the top of the stack is negative return End a subroutine and transfer control back to the caller halt End the program I/O (IMP: [Tab][LF]) Finally, we need to be able to interact with the user. There are IO instructions for reading and writing numbers and individual characters. With these, string manipulation routines can be written. The read instructions take the heap address in which to store the result from the top of the stack. print chr Output the character at the top of the stack print int Output the number at the top of the stack input chr Read a character and place it in the location given by the top of the stack input int Read a number and place it in the location given by the top of the stack Question: How would you redesign, rewrite, or rename the previous mnemonics and for what reasons?

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• How to pass parameters to manage_shared_memory.construct() in Boost.Interprocess

  - by recipriversexclusion

  I've stared at the Boost.Interprocess documentation for hours but still haven't been able to figure this out. In the doc, they have an example of creating a vector in shared memory like so: //Define an STL compatible allocator of ints that allocates from the managed_shared_memory. //This allocator will allow placing containers in the segment typedef allocator<int, managed_shared_memory::segment_manager> ShmemAllocator; //Alias a vector that uses the previous STL-like allocator so that allocates //its values from the segment typedef vector<int, ShmemAllocator> MyVector; int main(int argc, char *argv[]) { //Create a new segment with given name and size managed_shared_memory segment(create_only, "MySharedMemory", 65536); //Initialize shared memory STL-compatible allocator const ShmemAllocator alloc_inst (segment.get_segment_manager()); //Construct a vector named "MyVector" in shared memory with argument alloc_inst MyVector *myvector = segment.construct<MyVector>("MyVector")(alloc_inst); Now, I understand this. What I'm stuck is how to pass a second parameter to segment.construct() to specify the number of elements. The interprocess document gives the prototype for construct() as MyType *ptr = managed_memory_segment.construct<MyType>("Name") (par1, par2...); but when I try MyVector *myvector = segment.construct<MyVector>("MyVector")(100, alloc_inst); I get compilation errors. My questions are: Who actually gets passed the parameters par1, par2 from segment.construct, the constructor of the object, e.g. vector? My understanding is that the template allocator parameter is being passed. Is that correct? How can I add another parameter, in addition to alloc_inst that is required by the constructor of the object being created in shared memory? There's very little information other than the terse Boost docs on this.

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• Script to copy files on CD and not on hard disk to a new directory

  - by John22

  I need to copy files from a set of CDs that have a lot of duplicate content, with each other, and with what's already on my hard disk. The file names of identical files are not the same, and are in sub-directories of different names. I want to copy non-duplicate files from the CD into a new directory on the hard disk. I don't care about the sub-directories - I will sort it out later - I just want the unique files. I can't find software to do that - see my post at SuperUser http://superuser.com/questions/129944/software-to-copy-non-duplicate-files-from-cd-dvd Someone at SuperUser suggested I write a script using GNU's "find" and the Win32 version of some checksum tools. I glanced at that, and have not done anything like that before. I'm hoping something exists that I can modify. I found a good program to delete duplicates, Duplicate Cleaner (it compares checksums), but it won't help me here, as I'd have to copy all the CDs to disk, and each is probably about 80% duplicates, and I don't have room to do that - I'd have to cycle through a few at a time copying everything, then turning around and deleting 80% of it, working the hard drive a lot. Thanks for any help.

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• How to perform spatial partitioning in n-dimensions?

  - by kevin42

  I'm trying to design an implementation of Vector Quantization as a c++ template class that can handle different types and dimensions of vectors (e.g. 16 dimension vectors of bytes, or 4d vectors of doubles, etc). I've been reading up on the algorithms, and I understand most of it: here and here I want to implement the Linde-Buzo-Gray (LBG) Algorithm, but I'm having difficulty figuring out the general algorithm for partitioning the clusters. I think I need to define a plane (hyperplane?) that splits the vectors in a cluster so there is an equal number on each side of the plane. [edit to add more info] This is an iterative process, but I think I start by finding the centroid of all the vectors, then use that centroid to define the splitting plane, get the centroid of each of the sides of the plane, continuing until I have the number of clusters needed for the VQ algorithm (iterating to optimize for less distortion along the way). The animation in the first link above shows it nicely. My questions are: What is an algorithm to find the plane once I have the centroid? How can I test a vector to see if it is on either side of that plane?

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• Debugging fortran code in Eclipse with Photran and GDB debugger: missing symbols

  - by tvandenbrande

  I have a program, written in fortran90, previously successfully compiled on a compaq compiler and working, that I'm now trying to compile with gfortran. I can compile the code to an .exe and run it. It works fine until a certain point in the routine and then an error is thrown. My current configuration: Windows 7 Eclipse Juno with CDT Photran Cygwin installation with gfortran compiler and GDB debugger (gdb.exe) Configurations for the debugger: GDB command set: Standard (Windows) Protocol: mi Shared libraries: don't load shared library symbols automatically (when activating this, no changes are noted). When running the debug command I get the following output: .gdbinit: No such file or directory. Reading symbols from /cygdrive/c/Users/thys/Documents/doctoraat/12_in progress/Hamfem/Debug/Hamfem.exe...done. auto-solib-add on Undefined command: "auto-solib-add". Try "help". Warning: C:/Users/thys/Documents/doctoraat/12_in progress/Hamfem/Hamfem/in: No such file or directory. [New Thread 5816.0x1914] [New Thread 5816.0x654] Basicly that leaves me with 2 questions: Where can I find the .gdbinit file in the cygwin installation? Are there any other possible errors in my setup, or points to think about?

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• Help needed in grokking password hashes and salts

  - by javafueled

  I've read a number of SO questions on this topic, but grokking the applied practice of storing a salted hash of a password eludes me. Let's start with some ground rules: a password, "foobar12" (we are not discussing the strength of the password). a language, Java 1.6 for this discussion a database, postgreSQL, MySQL, SQL Server, Oracle Several options are available to storing the password, but I want to think about one (1): Store the password hashed with random salt in the DB, one column Found on SO and elsewhere is the automatic fail of plaintext, MD5/SHA1, and dual-columns. The latter have pros and cons MD5/SHA1 is simple. MessageDigest in Java provides MD5, SHA1 (through SHA512 in modern implementations, certainly 1.6). Additionally, most RDBMSs listed provide methods for MD5 encryption functions on inserts, updates, etc. The problems become evident once one groks "rainbow tables" and MD5 collisions (and I've grokked these concepts). Dual-column solutions rest on the idea that the salt does not need to be secret (grok it). However, a second column introduces a complexity that might not be a luxury if you have a legacy system with one (1) column for the password and the cost of updating the table and the code could be too high. But it is storing the password hashed with a random salt in single DB column that I need to understand better, with practical application. I like this solution for a couple of reasons: a salt is expected and considers legacy boundaries. Here's where I get lost: if the salt is random and hashed with the password, how can the system ever match the password? I have theory on this, and as I type I might be grokking the concept: Given a random salt of 128 bytes and a password of 8 bytes ('foobar12'), it could be programmatically possible to remove the part of the hash that was the salt, by hashing a random 128 byte salt and getting the substring of the original hash that is the hashed password. Then re hashing to match using the hash algorithm...??? So... any takers on helping. :) Am I close?

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• Reading a large file into Perl array of arrays and manipulating the output for different purposes

  - by Brian D.

  Hello, I am relatively new to Perl and have only used it for converting small files into different formats and feeding data between programs. Now, I need to step it up a little. I have a file of DNA data that is 5,905 lines long, with 32 fields per line. The fields are not delimited by anything and vary in length within the line, but each field is the same size on all 5905 lines. I need each line fed into a separate array from the file, and each field within the line stored as its own variable. I am having no problems storing one line, but I am having difficulties storing each line successively through the entire file. This is how I separate the first line of the full array into individual variables: my $SampleID = substr("@HorseArray", 0, 7); my $PopulationID = substr("@HorseArray", 9, 4); my $Allele1A = substr("@HorseArray", 14, 3); my $Allele1B = substr("@HorseArray", 17, 3); my $Allele2A = substr("@HorseArray", 21, 3); my $Allele2B = substr("@HorseArray", 24, 3); ...etc. My issues are: 1) I need to store each of the 5905 lines as a separate array. 2) I need to be able to reference each line based on the sample ID, or a group of lines based on population ID and sort them. I can sort and manipulate the data fine once it is defined in variables, I am just having trouble constructing a multidimensional array with each of these fields so I can reference each line at will. Any help or direction is much appreciated. I've poured over the Q&A sections on here, but have not found the answer to my questions yet. Thanks!! -Brian

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• Using SDK 3.2 API in Universal iPhone/iPad application

  - by psychotik

  I have a project configured (I think) to produce Universal binaries. The base SDK is set to 3.2 and the Deployment Target is set to 3.1. Target Device Family is iPhone/iPad and the architecture is armv6 armv7. I had a few questions about how this Universal binary thing really works: 1) When I want to submit an app binary for review, what configuration should I set as the build target? If I set it as "Device - 3.1" I get a warning which says "warning: building with Targeted Device Family" that includes iPad('1,2') requires building with the 3.2 or later SDK". However, if I build with SDK 3.2, will it still run on iPhones with OS 3.1? What's the right configuration for device and architecture (arm6/arm7)? 2) How do I test the scenario above (built with SDK 3.2, but installed on a device running OS 3.1)? If I build with SDK 3.2, when I try to install it on a phone with OS 3.1, I get an error saying that the phone's OS isn't updated. Thanks!

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• ANTLR Tree Grammar and StringTemplate Code Translation

  - by Behrooz Nobakht

  I am working on a code translation project with a sample ANTLR tree grammar as: start: ^(PROGRAM declaration+) -> program_decl_tmpl(); declaration: class_decl | interface_decl; class_decl: ^(CLASS ^(ID CLASS_IDENTIFIER)) -> class_decl_tmpl(cid={$CLASS_IDENTIFIER.text}); The group template file for it looks like: group My; program_decl_tmpl() ::= << *WHAT?* >> class_decl_tmpl(cid) ::= << public class <cid> {} >> Based on this, I have these questions: Everything works fine apart from that what I should express in WHAT? to say that a program is simply a list of class declarations to get the final generated output? Is this approach averagely suitable for not so a high-level language? I have also studied ANTLR Code Translation with String Templates, but it seems that this approach takes much advantage of interleaving code in tree grammar. Is it also possible to do it as much as possible just in String Templates?

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• Will the following NHibernate interface mapping work?

  - by Ben Aston

  I'd like to program against interfaces when working with NHibernate due to type dependency issues within the solution I am working with. SO questions such as this indicate it is possible. I have an ILocation interface and a concrete Location type. Will the following work? HBM mapping: <class name="ILocation" abstract="true" table="ILocation"> <id name="Id" type="System.Guid" unsaved-value="00000000-0000-0000-0000-000000000000"> <column name="LocationId" /> <generator class="guid" /> </id> <union-subclass table="Location" name="Location"> <property name="Name" type="System.String"/> </union-subclass> </class> Detached criteria usage using the interface: var criteria = DetachedCriteria.For<ILocation>().Add(Restrictions.Eq("Name", "blah")); var locations = criteria.GetExecutableCriteria(UoW.Session).List<ILocation>(); Are there any issues with not using the hilo ID generator and/or with this approach in general?

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• getchar does not stop when using scanf

  - by Oz123

  I am have a difficulty understanding getchar(). In the following program getchar works as expected: #include <stdio.h> int main() { printf("Type Enter to continue..."); getchar(); return 0; } However, in the following program, getchar does not create a delay and the program ends: #include <stdio.h> int main() { char command[100]; scanf("%s", command ); printf("Type Enter to continue..."); getchar(); return 0; } I have the following weired workaround, which works, but I understand why: #include <stdio.h> int main() { char command[100]; int i; scanf("%s", command ); printf("Type Enter to continue..."); while ( getchar() != '\n') { i=0; } getchar(); return 0; } So my questions are: 1. What is scanf doing? Why does scanf do this ? 2. Why is my work around working? 3. What is a good way to emulate the following Python code: raw_input("Type Enter to continue")

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• How to make a small flash swf with ComboBox in Actionscript 3?

  - by Sint

  I have a pure Actionscript 3 project, using flash.* libraries, compiles down to about 6k (using mxmlc). Program handles about 1k shapes, a few sprites, a sockets connection, works great (tastes less filling). Now, how would I add a ComboBox control without incurring excessive bloat? More specificially, I would like to keep the size under 100k. So far I have tried: Adobe mx.controls ComboBoxexample - simple mxml example compiles to 200+k both on my main Linux Box using mxmlc and in Windows using Flash Builder 4 Yahoo Astra - uses mx libraries underneath(so as bloated as Adobe?), plus does not contain exact ComboBox Keith Peter's MinimalComps - seems small, but far from providing ComboBox functionality SPAS (Swing Package for Actionscript) - compiles to 130k, but alpha version of ComboBox does not let me adjust height... asuilib - compiles to 40k, unfortunately this ComboBox does not provide for scrolling items...if it does not fit on screen no way to scroll to it Now my questions: Is there a way to lower size for projects importing mx.controls ? Maybe there is a way to fix SPAS or asuilib ComboBoxes? Perhaps, there are some other libraries which provide a ComboBox(or DropList)?

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• Caching and accessing configuration data in ASP.NET MVC app.

  - by Sosh

  I'm about to take a look at how to implement internationalisation for an ASP.NET MVC project. I'm looking at how to allow the user to change languages. My initial though is a dropdownlist containing each of the supported langauages. Whoever a few questions have come to mind: How to store the list of supported languages? (e.g. just "en", "English"; "fr", "French" etc.) An xml file? .config files? If I store this in a file I'll have to cache this (at startup I guess). So, what would be best, load the xml data into a list (somehow) and store this list in the System.Web.Cache? Application State? How then to load this data into the view (for display in a dropdown)? Give the view direct access to the cache? Just want to make sure I'm going in the right direction here... Thank you.

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