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  • List iterator not dereferencable?

    - by Roderick
    Hi All I get the error "list iterator not dereferencable" when using the following code: bool done = false; while (!_list_of_messages.empty() && !done) { // request the next message to create a frame // DEBUG ERROR WHEN NEXT LINE IS EXECUTED: Counted_message_reader reader = *(_list_of_messages.begin()); if (reader.has_more_data()) { _list_of_frames.push_back(new Dlp_data_frame(reader, _send_compressed_frames)); done = true; } else { _list_of_messages.pop_front(); } } (The line beginning with "Counted_message_reader..." is the one giving the problem) Note that the error doesn't always occur but seemingly at random times (usually when there's lots of buffered data). _list_of_messages is declared as follows: std::list<Counted_message_reader> _list_of_messages; In the surrounding code we could do pop_front, push_front and size, empty or end checks on _list_of_messages but no erase calls. I've studied the STL documentation and can't see any glaring problems. Is there something wrong with the above code or do I have a memory leak somewhere? Thanks! Appreciated!

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  • How to find Tomcat's PID and kill it in python?

    - by 4herpsand7derpsago
    Normally, one shuts down Apache Tomcat by running its shutdown.sh script (or batch file). In some cases, such as when Tomcat's web container is hosting a web app that does some crazy things with multi-threading, running shutdown.sh gracefully shuts down some parts of Tomcat (as I can see more available memory returning to the system), but the Tomcat process keeps running. I'm trying to write a simple Python script that: Calls shutdown.sh Runs ps -aef | grep tomcat to find any process with Tomcat referenced If applicable, kills the process with kill -9 <PID> Here's what I've got so far (as a prototype - I'm brand new to Python BTW): #!/usr/bin/python # Imports import sys import subprocess # Load from imported module. if __init__ == "__main__": main() # Main entry point. def main(): # Shutdown Tomcat shutdownCmd = "sh ${TOMCAT_HOME}/bin/shutdown.sh" subprocess.call([shutdownCmd], shell=true) # Check for PID grepCmd = "ps -aef | grep tomcat" grepResults = subprocess.call([grepCmd], shell=true) if(grepResult.length > 1): # Get PID and kill it. pid = ??? killPidCmd = "kill -9 $pid" subprocess.call([killPidCmd], shell=true) # Exit. sys.exit() I'm struggling with the middle part - with obtaining the grep results, checking to see if their size is greater than 1 (since grep always returns a reference to itself, at least 1 result will always be returned, methinks), and then parsing that returned PID and passing it into the killPidCmd. Thanks in advance!

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  • Displaying Flex Object References

    - by Pie21
    I have a bit of a memory leak issue in my Flex application, and the short version of my question is: is there any way (in AcitonScript 3) to find all live references to a given object? What I have is a number of views with presentation models behind each of them (using Swiz). The views of interest are children of a TabNavigator, so when I close the tab, the view is removed from the stage. When the view is removed from the stage, Swiz sets the model reference in the view to null, as it should. I also removeAllChildren() from the view. However when profiling the application, when I do this and run a GC, neither the view nor the presentation model are freed (though both set their references to each other to null). One model object used by the view (not a presenter, though) IS freed, so it's not completely broken. I've only just started profiling today (firmly believing in not optimising too early), so I imagine there's some kind of reference floating around somewhere, but I can't see where, and what would be super helpful would be the ability to debug and see a list of objects that reference the target object. Is this at all possible, and if not natively, is there some light-weight way to code this into future apps for debugging purposes? Cheers.

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  • How to get address of va_arg?

    - by lionbest
    I hack some old C API and i got a compile error with the following code: void OP_Exec( OP* op , ... ) { int i; va_list vl; va_start(vl,op); for( i = 0; i < op->param_count; ++i ) { switch( op->param_type[i] ) { case OP_PCHAR: op->param_buffer[i] = va_arg(vl,char*); // ok it works break; case OP_INT: op->param_buffer[i] = &va_arg(vl,int); // error here break; // ... more here } } op->pexec(op); va_end(vl); } The error with gcc version 4.4.1 (Ubuntu 4.4.1-4ubuntu9) was: main.c|55|error: lvalue required as unary ‘&’ operand So why exactly it's not possible here to get a pointer to argument? How to fix it? This code is executed very often with different OP*, so i prefer to not allocate extra memory. Is it possible to iterate over va_list knowing only the size of arguments?

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  • Weak hashmap with weak references to the values?

    - by Razor Storm
    I am building an android app where each entity has a bitmap that represents its sprite. However, each entity can be be duplicated (there might be 3 copies of entity asdf for example). One approach is to load all the sprites upfront, and then put the correct sprite in the constructors of the entities. However, I want to decode the bitmaps lazily, so that the constructors of the entities will decode the bitmaps. The only problem with this is that duplicated entities will load the same bitmap twice, using 2x the memory (Or n times if the entity is created n times). To fix this, I built a SingularBitmapFactory that will store a decoded Bitmap into a hash, and if the same bitmap is asked for again, will simply return the previously hashed one instead of building a new one. Problem with this, though, is that the factory holds a copy of all bitmaps, and so won't ever get garbage collected. What's the best way to switch the hashmap to one with weakly referenced values? In otherwords, I want a structure where the values won't be GC'd if any other object holds a reference to it, but as long as no other objects refers it, then it can be GC'd.

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  • How do you organise multiple git repositories?

    - by dbr
    With SVN, I had a single big repository I kept on a server, and checked-out on a few machines. This was a pretty good backup system, and allowed me easily work on any of the machines. I could checkout a specific project, commit and it updated the 'master' project, or I could checkout the entire thing. Now, I have a bunch of git repositories, for various projects, several of which are on github. I also have the SVN repository I mentioned, imported via the git-svn command.. Basically, I like having all my code (not just projects, but random snippets and scripts, some things like my CV, articles I've written, websites I've made and so on) in one big repository I can easily clone onto remote machines, or memory-sticks/harddrives as backup. The problem is, since it's a private repository, and git doesn't allow checking out of a specific folder (that I could push to github as a separate project, but have the changes appear in both the master-repo, and the sub-repos) I could use the git submodule system, but it doesn't act how I want it too (submodules are pointers to other repositories, and don't really contain the actual code, so it's useless for backup) Currently I have a folder of git-repos (for example, ~/code_projects/proj1/.git/ ~/code_projects/proj2/.git/), and after doing changes to proj1 I do git push github, then I copy the files into ~/Documents/code/python/projects/proj1/ and do a single commit (instead of the numerous ones in the individual repos). Then do git push backupdrive1, git push mymemorystick etc So, the question: How do your personal code and projects with git repositories, and keep them synced and backed-up?

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  • cell and array in Matlab

    - by Tim
    Hi, I am a little confused about the usage of cell and array in Matlab. I would like to hear about your understandings. Here are my observations: (1). array can dynamically adjust its own memory to allow dynamic number of elements, while cell seems not act in the same way. a=[]; a=[a 1]; b={}; b={b 1}; (2). several elements can be retrieved from cell, while they seem not from array. a={'1' '2'}; figure, plot(...); hold on; plot(...) ; legend(a{1:2}); b=['1' '2']; figure, plot(...); hold on; plot(...) ; legend(b(1:2)); % b(1:2) is an array, not its elements, so it is wrong with legend. Are these correct? What are some other different usages between the cell and array? Thanks and regards!

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  • CreateThread() fails on 64 bit Windows, works on 32 bit Windows. Why?

    - by Stephen Kellett
    Operating System: Windows XP 64 bit, SP2. I have an unusual problem. I am porting some code from 32 bit to 64 bit. The 32 bit code works just fine. But when I call CreateThread() for the 64 bit version the call fails. I have three places where this fails. 2 call CreateThread(). 1 calls beginthreadex() which calls CreateThread(). All three calls fail with error code 0x3E6, "Invalid access to memory location". The problem is all the input parameters are correct. HANDLE h; DWORD threadID; h = CreateThread(0, // default security 0, // default stack size myThreadFunc, // valid function to call myParam, // my param 0, // no flags, start thread immediately &threadID); All three calls to CreateThread() are made from a DLL I've injected into the target program at the start of the program execution (this is before the program has got to the start of main()/WinMain()). If I call CreateThread() from the target program (same params) via say a menu, it works. Same parameters etc. Bizarre. If I pass NULL instead of &threadID, it still fails. If I pass NULL as myParam, it still fails. I'm not calling CreateThread from inside DllMain(), so that isn't the problem. I'm confused and searching on Google etc hasn't shown any relevant answers. If anyone has seen this before or has any ideas, please let me know. Thanks for reading.

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  • Why does multiple sessions started on the same page gets the same session id?

    - by Calmarius
    I tryed the following: <?php session_name('user'); session_start(); // sets an 'user' cookie with session id. // This session stores the user's login data. // Its an ordinary session. $USERSESSION=$_SESSION; // saving this session $userSessId=session_id(); session_write_close(); //closing this session session_name('chatroom'); session_start(); // set a 'chatroom' cookie but contains the same session id and points to the same data :( . // This session would be used to store the chat text. This session would be // shared between all users joined in this chat room by setting the same session id for all members. // by calling session_regenerate_id would make a diffent session id for every user and it won't be a chat room anymore. ?> So I want to do a chat like thing with sessions. On the client side it would be done with ajax that polls this php page in every 5-10 seconds. Sessions may be cached in the server's memory so it can be accessible fast. I can store the chat in the database but my service runs on a free webhost which is limited, only 4 mysql connections allowed at a time which is almost nothing. I try to touch my database as least times as possible.

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  • Which fieldtype is best for storing PRICE values?

    - by BerggreenDK
    Hi there I am wondering whats the best "price field" in MSSQL for a shoplike structure? Looking at this overview: http://www.teratrax.com/sql_guide/data_types/sql_server_data_types.html We have datatypes called money, smallmoney, then we have decimal/numeric and lastly float and real Name, memory/disk-usage and value ranges: Money: 8 bytes (values: -922,337,203,685,477.5808 to +922,337,203,685,477.5807) Smallmoney: 4 bytes (values: -214,748.3648 to +214,748.3647) Decimal: 9 [default, min. 5] bytes (values: -10^38 +1 to 10^38 -1 ) Float: 8 bytes (values: -1.79E+308 to 1.79E+308 ) Real: 4 bytes (values: -3.40E+38 to 3.40E+38 ) My question is: is it really wise to store pricevalues in those types? what about eg. INT? Int: 4 bytes (values: -2,147,483,648 to 2,147,483,647) Lets say a shop uses dollars, they have cents, but I dont see prices being $49.2142342 so the use of a lot of decimals showing cents seems waste of SQL bandwidth. Secondly, most shops wouldn't show any prices near 200.000.000 (not in normal webshops at least... unless someone is trying to sell me a famous tower in Paris) So why not go for an int? An int is fast, its only 4 bytes and you can easily make decimals, by saving values in cents instead of dollars and then divide when you present the values. The other approach would be to use smallmoney which is 4 bytes too, but this will require the math part of the CPU to do the calc, where as Int is integer power... on the downside you will need to divide every single outcome. Are there any "currency" related problems with regionalsettings when using smallmoney/money fields? what will these transfer too in C#/.NET ? Any pros/cons? Go for integer prices or smallmoney or some other? Whats does your experience tell?

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  • Creating a complex tree model in Qt

    - by Zeke
    I'm writing an IRC Client (yes another one). Long story short. I'm writing a Server dialogue that keeps a list of this: Identity Networks Channels Addresses I have 3 different list views that will be for the Networks, Channels and Addresses. When the user changes the Identity (combo box). The network listview will lookup all the networks for that specific Identity. After it loads up the Networks it will automatically select the first network and then load all the channels and addresses for that specific network. The problem is I want to have 3 views for 1 model, to minimise all the memory and the loading of data. So that it makes it much easier to manage and not do a bunch of work. If you'd look at QColumnView it's the same exact thing. But I don't need it to be on one exact page since the views are on entirely different tabs to make it easier to go through the Server dialogue. I'm wondering what will be the best way to go about handling this complexity. The information is stored in a SQLite database. I already have the classes written to extract and store it. Just the modelling is the painful part of this solution.

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  • Drawing and filling different polygons at the same time in MATLAB

    - by Hossein
    Hi,I have the code below. It load a CSV file into memory. This file contains the coordinates for different polygons.Each row of this file has X,Y coordinates and a string which tells that to which polygon this datapoint belongs. for example a polygone named "Poly1" with 100 data points has 100 rows in this file like : Poly1,X1,Y1 Poly1,X2,Y2 ... Poly1,X100,Y100 Poly2,X1,Y1 ..... The index.csv file has the number of datapoint(number of rows) for each polygon in file Polygons.csv. These details are not important. The thing is: I can successfully extract the datapoints for each polygon using the code below. However, When I plot the lines of different polygons are connected to each other and the plot looks crappy. I need the polygons to be separated(they are connected and overlapping the some areas though). I thought by using "fill" I can actually see them better. But "fill" just filles every polygon that it can find and that is not desirable. I only want to fill inside the polygons. Can someone help me? I can also send you my datapoint if necessary, they are less than 200Kb. Thanks [coordinates,routeNames,polygonData] = xlsread('Polygons.csv'); index = dlmread('Index.csv'); firstPointer = 0 lastPointer = index(1) for Counter=2:size(index) firstPointer = firstPointer + index(Counter) + 1 hold on plot(coordinates(firstPointer:lastPointer,2),coordinates(firstPointer:lastPointer,1),'r-') lastPointer = lastPointer + index(Counter) end

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  • Building "isolated" and "automatically updated" caches (java.util.List) in Java.

    - by Aidos
    Hi Guys, I am trying to write a framework which contains a lot of short-lived caches created from a long-living cache. These short-lived caches need to be able to return their entier contents, which is a clone from the original long-living cache. Effectively what I am trying to build is a level of transaction isolation for the short-lived caches. The user should be able to modify the contents of the short-lived cache, but changes to the long-living cache should not be propogated through (there is also a case where the changes should be pushed through, depending on the Cache type). I will do my best to try and explain: master-cache contains: [A,B,C,D,E,F] temporary-cache created with state [A,B,C,D,E,F] 1) temporary-cache adds item G: [A,B,C,D,E,F] 2) temporary-cache removes item B: [A,C,D,E,F] master-cache contains: [A,B,C,D,E,F] 3) master-cache adds items [X,Y,Z]: [A,B,C,D,E,F,X,Y,Z] temporary-cache contains: [A,C,D,E,F] Things get even harder when the values in the items can change and shouldn't always be updated (so I can't even share the underlying object instances, I need to use clones). I have implemented the simple approach of just creating a new instance of the List using the standard Collection constructor on ArrayList, however when you get out to about 200,000 items the system just runs out of memory. I know the value of 200,000 is excessive to iterate, but I am trying to stress my code a bit. I had thought that it might be able to somehow "proxy" the list, so the temporary-cache uses the master-cache, and stores all of it's changes (effectively a Memento for the change), however that quickly becomes a nightmare when you want to iterate the temporary-cache, or retrieve an item at a specific index. Also given that I want some modifications to the contents of the list to come through (depending on the type of the temporary-cache, whether it is "auto-update" or not) and I get completly out of my depth. Any pointers to techniques or data-structures or just general concepts to try and research will be greatly appreciated. Cheers, Aidos

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  • MS Access Bulk Insert exits app

    - by Brij
    In the web service, I have to bulk insert data in MS Access database. First, There was single complex Insert-Select query,There was no error but app exited after inserting some records. I have divided the query to make it simple and using linq to remove complexity of query. now I am inserting records using for loop. there are approx 10000 records. Again, same problem. I put a breakpoint after loop, but No hit. I have used try catch, but no error found. For Each item In lstSelDel Try qry = String.Format("insert into Table(Id,link,file1,file2,pID) values ({0},""{1}"",""{2}"",""{3}"",{4})", item.WebInfoID, item.Links, item.Name, item.pName, pDateID) DAL.ExecN(qry) Catch ex As Exception Throw ex End Try Next Public Shared Function ExecN(ByVal SQL As String) As Integer Dim ret As Integer = -1 Dim nowConString As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + System.AppDomain.CurrentDomain.BaseDirectory + "DataBase\\mydatabase.mdb;" Dim nowCon As System.Data.OleDb.OleDbConnection nowCon = New System.Data.OleDb.OleDbConnection(nowConString) Dim cmd As New OleDb.OleDbCommand(SQL, nowCon) nowCon.Open() ret = cmd.ExecuteNonQuery() nowCon.Close() nowCon.Dispose() cmd.Dispose() Return ret End Function After exiting app, I see w3wp.exe uses more than 50% of Memory. Any idea, What is going wrong? Is there any limitation of MS Access?

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  • python crc32 woes

    - by lazyr
    I'm writing a python program to extract data from the middle of a 6 GB bz2 file. A bzip2 file is made up of independently decryptable blocks of data, so I only need to find a block (they are delimited by magic bits), then create a temporary one-block bzip2 file from it in memory, and finally pass that to the bz2.decompress function. Easy, no? The bzip2 format has a crc32 checksum for the file at the end. No problem, binascii.crc32 to the rescue. But wait. The data to be checksummed does not necessarily end on a byte boundary, and the crc32 function operates on a whole number of bytes. My plan: use the binascii.crc32 function on all but the last byte, and then a function of my own to update the computed crc with the last 1-7 bits. But hours of coding and testing has left me bewildered, and my puzzlement can be boiled down to this question: how come crc32("\x00") is not 0x00000000? Shouldn't it be, according to the wikipedia article? You start with 0b00000000 and pad with 32 0's, then do polynomial division with 0x04C11DB7 until there are no ones left in the first 8 bits, which is immediately. Your last 32 bits is the checksum, and how can that not be all zeroes? I've searched google for answers and looked at the code of several crc32 implementations without finding any clue to why this is so.

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  • Explanation of `self` usage during dealloc?

    - by Greg
    I'm trying to lock down my understanding of proper memory management within Objective-C. I've gotten into the habit of explicitly declaring self.myProperty rather than just myProperty because I was encountering occasional scenarios where a property would not be set to the reference that I intended. Now, I'm reading Apple documentation on releasing IBOutlets, and they say that all outlets should be set to nil during dealloc. So, I put this in place as follows and experienced crashes as a result: - (void)dealloc { [self.dataModel close]; [self.dataModel release], self.dataModel = nil; [super dealloc]; } So, I tried taking out the "self" references, like so: - (void)dealloc { [dataModel close]; [dataModel release], dataModel = nil; [super dealloc]; } This second system seems to work as expected. However, it has me a bit confused. Why would self cause a crash in that case, when I thought self was a fairly benign reference more used as a formality than anything else? Also, if self is not appropriate in this case, then I have to ask: when should you include self references, and when should you not?

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  • What is the fastest way to filter a list of strings when making an Intellisense/Autocomplete list?

    - by user559548
    Hello everyone, I'm writing an Intellisense/Autocomplete like the one you find in Visual Studio. It's all fine up until when the list contains probably 2000+ items. I'm using a simple LINQ statement for doing the filtering: var filterCollection = from s in listCollection where s.FilterValue.IndexOf(currentWord, StringComparison.OrdinalIgnoreCase) >= 0 orderby s.FilterValue select s; I then assign this collection to a WPF Listbox's ItemSource, and that's the end of it, works fine. Noting that, the Listbox is also virtualised as well, so there will only be at most 7-8 visual elements in memory and in the visual tree. However the caveat right now is that, when the user types extremely fast in the richtextbox, and on every key up I execute the filtering + binding, there's this semi-race condition, or out of sync filtering, like the first key stroke's filtering could still be doing it's filtering or binding work, while the fourth key stroke is also doing the same. I know I could put in a delay before applying the filter, but I'm trying to achieve a seamless filtering much like the one in Visual Studio. I'm not sure where my problem exactly lies, so I'm also attributing it to IndexOf's string operation, or perhaps my list of string's could be optimised in some kind of index, that could speed up searching. Any suggestions of code samples are much welcomed. Thanks.

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  • Using SMO to call Database.ExecuteNonQuery() concurrently?

    - by JimDaniel
    I have been banging my head against the wall trying to figure out how I can run update scripts concurrently against multiple databases in a single SQL Server instance using SMO. Our environments have an ever-increasing number of databases which need updating, and iterating through one at a time is becoming a problem (too slow). From what I understand SMO does not support concurrent operations, and my tests have bore that out. There seems to be shared memory at the Server object level, for things like DataReader context, keeps throwing exceptions such as "reader is already open." I apologize for not having the exact exceptions I am getting. I will try to get them and update this post. I am no expert on SMO and just feeling my way through to be honest. Not really sure I am approaching it the right way, but it's something that has to be done, or our productivity will slow to a crawl. So how would you guys do something like this? Am I using the wrong technology with SMO? All I am wanting to do is execute sql scripts against databases in a single sql server instance in parallel. Thanks for any help you can give, Daniel

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  • How to get the size of a binary tree ?

    - by Andrei Ciobanu
    I have a very simple binary tree structure, something like: struct nmbintree_s { unsigned int size; int (*cmp)(const void *e1, const void *e2); void (*destructor)(void *data); nmbintree_node *root; }; struct nmbintree_node_s { void *data; struct nmbintree_node_s *right; struct nmbintree_node_s *left; }; Sometimes i need to extract a 'tree' from another and i need to get the size to the 'extracted tree' in order to update the size of the initial 'tree' . I was thinking on two approaches: 1) Using a recursive function, something like: unsigned int nmbintree_size(struct nmbintree_node* node) { if (node==NULL) { return(0); } return( nmbintree_size(node->left) + nmbintree_size(node->right) + 1 ); } 2) A preorder / inorder / postorder traversal done in an iterative way (using stack / queue) + counting the nodes. What approach do you think is more 'memory failure proof' / performant ? Any other suggestions / tips ? NOTE: I am probably going to use this implementation in the future for small projects of mine. So I don't want to unexpectedly fail :).

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  • Code Golf: Counting XML elements in file on Android

    - by CSharperWithJava
    Take a simple XML file formatted like this: <Lists> <List> <Note/> ... <Note/> </List> <List> <Note/> ... <Note/> </List> </Lists> Each node has some attributes that actually hold the data of the file. I need a very quick way to count the number of each type of element, (List and Note). Lists is simply the root and doesn't matter. I can do this with a simple string search or something similar, but I need to make this as fast as possible. Design Parameters: Must be in java (Android application). Must AVOID allocating memory as much as possible. Must return the total number of Note elements and the number of List elements in the file, regardless of location in file. Number of Lists will typically be small (1-4), and number of notes can potentially be very large (upwards of 1000, typically 100) per file. I look forward to your suggestions.

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  • How do the operators < and > work with pointers?

    - by Øystein
    Just for fun, I had a std::list of const char*, each element pointing to a null-terminated text string, and ran a std::list::sort() on it. As it happens, it sort of (no pun intended) did not sort the strings. Considering that it was working on pointers, that makes sense. According to the documentation of std::list::sort(), it (by default) uses the operator < between the elements to compare. Forgetting about the list for a moment, my actual question is: How do these (, <, =, <=) operators work on pointers in C++ and C? Do they simply compare the actual memory addresses? char* p1 = (char*) 0xDAB0BC47; char* p2 = (char*) 0xBABEC475; e.g. on a 32-bit, little-endian system, p1 p2 because 0xDAB0BC47 0xBABEC475? Testing seems to confirm this, but I thought it'd be good to put it on StackOverflow for future reference. C and C++ both do some weird things to pointers, so you never really know...

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  • Negative number representation across multiple architechture

    - by Donotalo
    I'm working with OKI 431 micro controller. It can communicate with PC with appropriate software installed. An EEPROM is connected in the I2C bus of the micro which works as permanent memory. The PC software can read from and write to this EEPROM. Consider two numbers, B and C, each is two byte integer. B is known to both the PC software and the micro and is a constant. C will be a number so close to B such that B-C will fit in a signed 8 bit integer. After some testing, appropriate value for C will be determined by PC and will be stored into the EEPROM of the micro for later use. Now the micro can store C in two ways: The micro can store whole two byte representing C The micro can store B-C as one byte signed integer, and can later derive C from B and B-C I think that two's complement representation of negative number is now universally accepted by hardware manufacturers. Still I personally don't like negative numbers to be stored in a storage medium which will be accessed by two different architectures because negative number can be represented in different ways. For you information, 431 also uses two's complement. Should I get rid of the headache that negative number can be represented in different ways and accept the one byte solution as my other team member suggested? Or should I stick to the decision of the two byte solution because I don't need to deal with negative numbers? Which one would you prefer and why?

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  • Read/Write/Find/Replace huge csv file

    - by notapipe
    I have a huge (4,5 GB) csv file.. I need to perform basic cut and paste, replace operations for some columns.. the data is pretty well organized.. the only problem is I cannot play with it with Excel because of the size (2000 rows, 550000 columns). here is some part of the data: ID,Affection,Sex,DRB1_1,DRB1_2,SENum,SEStatus,AntiCCP,RFUW,rs3094315,rs12562034,rs3934834,rs9442372,rs3737728 D0024949,0,F,0101,0401,SS,yes,?,?,A_A,A_A,G_G,G_G D0024302,0,F,0101,7,SN,yes,?,?,A_A,G_G,A_G,?_? D0023151,0,F,0101,11,SN,yes,?,?,A_A,G_G,G_G,G_G I need to remove 4th, 5th, 6th, 7th, 8th and 9th columns; I need to find every _ character from column 10 onwards and replace it with a space ( ) character; I need to replace every ? with zero (0); I need to replace every comma with a tab; I need to remove first row (that has column names; I need to replace every 0 with 1, every 1 with 2 and every ? with 0 in 2nd column; I need to replace F with 2, M with 1 and ? with 0 in 3rd column; so that in the resulting file the output reads: D0024949 1 2 A A A A G G G G D0024302 1 2 A A G G A G 0 0 D0023151 1 2 A A G G G G G G (both input and output should read one line per row, ne extra blank row) Is there a memory efficient way of doing that with java(and I need a code to do that) or a usable tool for playing with this large data so that I can easily apply Excel functionality..

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  • Multi-reader IPC solution?

    - by gct
    I'm working on a framework in C++ (just for fun for now), that lets the user write plugins that use a standard API to stream data between each other. There's going to be three basic transport mechanisms for the data: files, sockets, and some kind of IPC piping system. The system is set up so that for the non-file transport, each stream can have multiple readers. IE once a server socket it setup, multiple computers can connect and stream the data. I'm a little stuck at the multi-reader IPC system though. All my plugins run in threads so they live in the same address space, so some kind of shared memory system would work fine, I was thinking I'd write my own circular buffer with a write pointer and read pointers chassing it around the buffer, but I have my doubts that I can achieve the same performance as something like linux pipes. I'm curious what people would suggest for a multi-reader solution to something like this? Is the overhead for pipes or domain sockets low enough that I could just open a connection to each reader and issue separate writes to each reader? This is intended to be significant volumes of data (tens of mega-samples/sec), so performance is a must.

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  • function returns after an XMLHttpRequest

    - by ashays
    Alright, I know questions like this have probably been asked dozens of times, but I can't seem to find a working solution for my project. Recently, while using jQuery for a lot of AJAX calls, I've found myself in a form of callback hell. Whether or not jQuery is too powerful for this project is beyond the scope of this question. So basically here's some code that shows what's going on: function check_form(table) { var file = "/models/"+table+".json"; var errs = {}; var xhr = $.getJSON(file, function(json) { for (key in json) { var k = key; var r = json[k]; $.extend(errs, check_item("#"+k,r)); } }); return errs; } And... as you can probably guess, I get an empty object returned. My original idea was to use some sort of onReadyStateChange idea that would return whenever the readyState had finally hit 4. This causes my application to hang indefinitely, though. I need these errors to decide whether or not the form is allowed to submit or not (as well as to tell the user where the errors are in the application. Any ideas? Edit. It's not the prettiest solution, but I've managed to get it to work. Basically, check_form has the json passed to it from another function, instead of loading it. I was already loading it there, too, so it's probably best that I don't continue to load the same file over and over again anyways. I was just worried about overloading memory. These files aren't absolutely huge, though, so I guess it's probably okay.

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