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  • Function with parameter type that has a copy-constructor with non-const ref chosen?

    - by Johannes Schaub - litb
    Some time ago I was confused by the following behavior of some code when I wanted to write a is_callable<F, Args...> trait. Overload resolution won't call functions accepting arguments by non-const ref, right? Why doesn't it reject in the following because the constructor wants a Test&? I expected it to take f(int)! struct Test { Test() { } // I want Test not be copyable from rvalues! Test(Test&) { } // But it's convertible to int operator int() { return 0; } }; void f(int) { } void f(Test) { } struct WorksFine { }; struct Slurper { Slurper(WorksFine&) { } }; struct Eater { Eater(WorksFine) { } }; void g(Slurper) { } void g(Eater) { } // chooses this, as expected int main() { // Error, why? f(Test()); // But this works, why? g(WorksFine()); } Error message is m.cpp: In function 'int main()': m.cpp:33:11: error: no matching function for call to 'Test::Test(Test)' m.cpp:5:3: note: candidates are: Test::Test(Test&) m.cpp:2:3: note: Test::Test() m.cpp:33:11: error: initializing argument 1 of 'void f(Test)' Can you please explain why one works but the other doesn't?

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  • Unable to persist objects in GAE JDO

    - by Basil Dsouza
    Hello Guys, I am completely fresh to both JDO and GAE, and have been struggling to get my data layer to persist any code at all! The issues I am facing may be very simple, but I just cant seem to find any a way no matter what solution I try. Firstly the problem: (Slightly simplified, but still contains all the info necessary) My data model is as such: User: (primary key) String emailID String firstName Car: (primary key) User user (primary key) String registration String model This was the initial datamodel. I implemented a CarPK object to get a composite primary key of the User and the registration. However that ran into a variety of issues. (Which i will save for another time/question) I then changed the design as such: User: (Unchanged) Car: (primary key) String fauxPK (here fauxPK = user.getEmailID() + SEP + registration) User user String registration String model This works fine for the user, and it can insert and retrieve user objects. However when i try to insert a Car Object, i get the following error: "Cannot have a java.lang.String primary key and be a child object" Found the following helpful link about it: http://stackoverflow.com/questions/2063467/persist-list-of-objects Went to the link suggested there, that explains how to create Keys, however they keep talking about "Entity Groups" and "Entity Group Parents". But I cant seem to find any articles or sites that explain what are "Entity Group"s or an "Entity Group Parents" I could try fiddling around some more to figure out if i can store an object somehow, But I am running sort on patience and also would rather understand and implement than vice versa. So i would appreciate any docs (even if its huge) that covers all these points, and preferably has some examples that go beyond the very basic data modeling. And thanks for reading such a long post :)

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  • MySQL query does not return any data

    - by Alex L
    Hi, I need to retrieve data from a specific time period. The query works fine until I specify the time period. Is there something wrong with the way I specify time period? I know there are many entries within that time-frame. This query returns empty: SELECT stop_times.stop_id, STR_TO_DATE(stop_times.arrival_time, '%H:%i:%s') as stopTime, routes.route_short_name, routes.route_long_name, trips.trip_headsign FROM trips JOIN stop_times ON trips.trip_id = stop_times.trip_id JOIN routes ON routes.route_id = trips.route_id WHERE stop_times.stop_id = 5508 HAVING stopTime BETWEEN DATE_SUB(stopTime,INTERVAL 1 MINUTE) AND DATE_ADD(stopTime,INTERVAL 20 MINUTE); Here is it's EXPLAIN: +----+-------------+------------+--------+------------------+---------+---------+-------------------------------+------+-------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+------------+--------+------------------+---------+---------+-------------------------------+------+-------------+ | 1 | SIMPLE | stop_times | ref | trip_id,stop_id | stop_id | 5 | const | 605 | Using where | | 1 | SIMPLE | trips | eq_ref | PRIMARY,route_id | PRIMARY | 4 | wmata_gtfs.stop_times.trip_id | 1 | | | 1 | SIMPLE | routes | eq_ref | PRIMARY | PRIMARY | 4 | wmata_gtfs.trips.route_id | 1 | | +----+-------------+------------+--------+------------------+---------+---------+-------------------------------+------+-------------+ 3 rows in set (0.00 sec) The query works if I remove the HAVING clause (don't specify time range). Returns: +---------+----------+------------------+-----------------+---------------+ | stop_id | stopTime | route_short_name | route_long_name | trip_headsign | +---------+----------+------------------+-----------------+---------------+ | 5508 | 06:31:00 | "80" | "" | "FORT TOTTEN" | | 5508 | 06:57:00 | "80" | "" | "FORT TOTTEN" | | 5508 | 07:23:00 | "80" | "" | "FORT TOTTEN" | | 5508 | 07:49:00 | "80" | "" | "FORT TOTTEN" | | 5508 | 08:15:00 | "80" | "" | "FORT TOTTEN" | | 5508 | 08:41:00 | "80" | "" | "FORT TOTTEN" | | 5508 | 09:08:00 | "80" | "" | "FORT TOTTEN" | I am using Google Transit format Data loaded into MySQL. The query is supposed to provide stop times and bus routes for a given bus stop. For a bus stop, I am trying to get: Route Name Bus Name Bus Direction (headsign) Stop time The results should be limited only to buses times from 1 min ago to 20 min from now. Please let me know if you could help.

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  • Assemblies mysteriously loaded into new AppDomains

    - by Eric
    I'm testing some code that does work whenever assemblies are loaded into an appdomain. For unit testing (in VS2k8's built-in test host) I spin up a new, uniquely-named appdomain prior to each test with the idea that it should be "clean": [TestInitialize()] public void CalledBeforeEachTestMethod() { AppDomainSetup appSetup = new AppDomainSetup(); appSetup.ApplicationBase = @"G:\<ProjectDir>\bin\Debug"; Evidence baseEvidence = AppDomain.CurrentDomain.Evidence; Evidence evidence = new Evidence( baseEvidence ); _testAppDomain = AppDomain.CreateDomain( "myAppDomain" + _appDomainCounter++, evidence, appSetup ); } [TestMethod] public void MissingFactoryCausesAppDomainUnload() { SupportingClass supportClassObj = (SupportingClass)_testAppDomain.CreateInstanceAndUnwrap( GetType().Assembly.GetName().Name, typeof( SupportingClass ).FullName ); try { supportClassObj.LoadMissingRegistrationAssembly(); Assert.Fail( "Should have nuked the app domain" ); } catch( AppDomainUnloadedException ) { } } [TestMethod] public void InvalidFactoryMethodCausesAppDomainUnload() { SupportingClass supportClassObj = (SupportingClass)_testAppDomain.CreateInstanceAndUnwrap( GetType().Assembly.GetName().Name, typeof( SupportingClass ).FullName ); try { supportClassObj.LoadInvalidFactoriesAssembly(); Assert.Fail( "Should have nuked the app domain" ); } catch( AppDomainUnloadedException ) { } } public class SupportingClass : MarshalByRefObject { public void LoadMissingRegistrationAssembly() { MissingRegistration.Main(); } public void LoadInvalidFactoriesAssembly() { InvalidFactories.Main(); } } If every test is run individually I find that it works correctly; the appdomain is created and has only the few intended assemblies loaded. However, if multiple tests are run in succession then each _testAppDomain already has assemblies loaded from all previous tests. Oddly enough, the two tests get appdomains with different names. The test assemblies that define MissingRegistration and InvalidFactories (two different assemblies) are never loaded into the unit test's default appdomain. Can anyone explain this behavior?

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  • Windows mobile 6.0 network settings

    - by Gauls
    Hi I am using Windows mobile 6.0 classic PDA's , I want to use wireless to access my service on the server(Win 2008), what should be my settings in the PDA network management? here's what my settings which works for some PDA's and for some it works for some time and stops? and for some PDA's similar settings does not work at all?? "Programs that connect to the internet..." = ISP "Programs that connect to a private network..." = My Work Network BTW what is this My work network ??? i don't understand as my PDA's use wireless (with proxy) i wud guess ISP to both should work right? but when i change second option to ISP as well the PDA that can connect to internet and server thru PDA IE but not through .netCF application will not get connected at all, but will work fine (apart from .netCF application accessing the server) if i change the second option back to My work network, so basically PDA is not using the first option of ISP at all ?? All i want to know is 1.) correct settings for WM 6.0 classic wirelessly accesing server 2008 with proxy 2) explain what is my work network ? Thanks gauls

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  • Output is different for R-value and L-value. Why?

    - by Leonid Volnitsky
    Can someone explain to me why output for R-value is different from L-value? #include <iostream> #include <vector> using namespace std; template<typename Ct> struct ct_wrapper { Ct&& ct; // R or L ref explicit ct_wrapper(Ct&& ct) : ct(std::forward<Ct>(ct)) { std::cout << this->ct[1];}; }; int main() { // L-val vector<int> v{1,2,3}; ct_wrapper<vector<int>&> lv(v); cout << endl << lv.ct[0] << lv.ct[1] << lv.ct[2] << endl; // R-val ct_wrapper<vector<int>&&> rv(vector<int>{1,2,3}); cout << endl << rv.ct[0] << rv.ct[1] << rv.ct[2] << endl; } Output (same for gcc48 and clang32): 2 123 2 003

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  • "One or more breakpoints cannot be set and have been disabled. Execution will stop at the beginning

    - by sam
    I set a breakpoint in my code in Visual-C++, but when I run, I see the error mentioned in the title. I know this question has been asked before on Stack Overflow (http://stackoverflow.com/questions/657470/breakpoints-cannot-be-set-and-have-been-disabled-problem), but none of the answers there fully explained the problem I'm seeing. The closest I can see is something about the linker, but I don't understand that - so if someone could explain in more detail that would be great. In my case, I have 2 projects in Visual C++ - the production dsw, and the test code dsw. I have loaded and rebuilt both dsws in debug mode. I want a breakpoint in the production code, which is run via the test scripts. My issue is I get the error message when I run the test code, because the break point is in the production code, which isn't loaded up when the test starts. Near the beginning of the test script there is a mytest_initialize() command. I imagine this goes off and loads up the production dll. Once this line has executed, I can put the breakpoint in my production code and run until I hit it. But it's quite annoying to have to run to this line, set the breakpoint and continue every time I want to run the test. So I think the problem is Visual C++ doesn't realise the two projects are related. Is this a linker issue? What does the linker do and what settings should I change to make this work? Thanks in advance. Apologies if instead I should be appending this question to the existing one, this is my first post so not quite sure how this should work.

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  • Need some help understanding this problem

    - by Legend
    I was wondering if someone could help me understand this problem. I prepared a small diagram because it is much easier to explain it visually. Problem I am trying to solve: 1. Constructing the dependency graph Given the connectivity of the graph and a metric that determines how well a node depends on the other, order the dependencies. For instance, I could put in a few rules saying that node 3 depends on node 4 node 2 depends on node 3 node 3 depends on node 5 But because the final rule is not "valuable" (again based on the same metric), I will not add the rule to my system. 2. Execute the request order Once I built a dependency graph, execute the list in an order that maximizes the final connectivity. First and foremost, I am wondering if I constructed the problem correctly and if I should be aware of any corner cases. Secondly, is there a closely related algorithm that I can look at? Currently, I am thinking of something like Feedback Arc Set or the Secretary Problem but I am a little confused at the moment. Any suggestions? PS: I am a little confused about the problem myself so please don't flame on me for that. If any clarifications are needed, I will try to update the question.

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  • At which line in the following code should I commit my unit of work?

    - by Pure.Krome
    I have the following code which is in a transaction. I'm not sure where/when I should be commiting my unit of work. On purpose, I've not mentioned what type of Respoistory i'm using - eg. Linq-To-Sql, Entity Framework 4, NHibernate, etc. If someone knows where, can they please explain WHY they have said, where? (i'm trying to understand the pattern through example(s), as opposed to just getting my code to work). Here's what i've got :- using ( TransactionScope transactionScope = new TransactionScope ( TransactionScopeOption.RequiresNew, new TransactionOptions { IsolationLevel = IsolationLevel.ReadUncommitted } ) ) { _logEntryRepository.InsertOrUpdate(logEntry); //_unitOfWork.Commit(); // Here, commit #1 ? // Now, if this log entry was a NewConnection or an LostConnection, // then we need to make sure we update the ConnectedClients. if (logEntry.EventType == EventType.NewConnection) { _connectedClientRepository.Insert( new ConnectedClient { LogEntryId = logEntry.LogEntryId }); //_unitOfWork.Commit(); // Here, commit #2 ? } // A (PB) BanKick does _NOT_ register a lost connection, // so we need to make sure we handle those scenario's as a LostConnection. if (logEntry.EventType == EventType.LostConnection || logEntry.EventType == EventType.BanKick) { _connectedClientRepository.Delete( logEntry.ClientName, logEntry.ClientIpAndPort); //_unitOfWork.Commit(); // Here, commit #3 ? } _unitOfWork.Commit(); // Here, commit #4 ? transactionScope.Complete(); }

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  • Using an SHA1 with Microsoft CAPI

    - by Erik Jõgi
    I have an SHA1 hash and I need to sign it. The CryptSignHash() method requires a HCRYPTHASH handle for signing. I create it and as I have the actual hash value already then set it: CryptCreateHash(cryptoProvider, CALG_SHA1, 0, 0, &hash); CryptSetHashParam(hash, HP_HASHVAL, hashBytes, 0); The hashBytes is an array of 20 bytes. However the problem is that the signature produced from this HCRYPTHASH handle is incorrect. I traced the problem down to the fact that CAPI actually doesn't use all 20 bytes from my hashBytes array. For some reason it thinks that SHA1 is only 4 bytes. To verify this I wrote this small program: HCRYPTPROV cryptoProvider; CryptAcquireContext(&cryptoProvider, NULL, NULL, PROV_RSA_FULL, 0); HCRYPTHASH hash; HCRYPTKEY keyForHash; CryptCreateHash(cryptoProvider, CALG_SHA1, keyForHash, 0, &hash); DWORD hashLength; CryptGetHashParam(hash, HP_HASHSIZE, NULL, &hashLength, 0); printf("hashLength: %d\n", hashLength); And this prints out hashLength: 4 ! Can anyone explain what I am doing wrong or why Microsoft CAPI thinks that SHA1 is 4 bytes (32 bits) instead of 20 bytes (160 bits).

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  • Common Lisp condition system for transfer of control

    - by Ken
    I'll admit right up front that the following is a pretty terrible description of what I want to do. Apologies in advance. Please ask questions to help me explain. :-) I've written ETLs in other languages that consist of individual operations that look something like: // in class CountOperation IEnumerable<Row> Execute(IEnumerable<Row> rows) { var count = 0; foreach (var row in rows) { row["record number"] = count++; yield return row; } } Then you string a number of these operations together, and call The Dispatcher, which is responsible for calling Operations and pushing data between them. I'm trying to do something similar in Common Lisp, and I want to use the same basic structure, i.e., each operation is defined like a normal function that inputs a list and outputs a list, but lazily. I can define-condition a condition (have-value) to use for yield-like behavior, and I can run it in a single loop, and it works great. I'm defining the operations the same way, looping through the inputs: (defun count-records (rows) (loop for count from 0 for row in rows do (signal 'have-value :value `(:count ,count @,row)))) The trouble is if I want to string together several operations, and run them. My first attempt at writing a dispatcher for these looks something like: (let ((next-op ...)) ;; pick an op from the set of all ops (loop (handler-bind ((have-value (...))) ;; records output from operation (setq next-op ...) ;; pick a new next-op (call next-op))) But restarts have only dynamic extent: each operation will have the same restart names. The restart isn't a Lisp object I can store, to store the state of a function: it's something you call by name (symbol) inside the handler block, not a continuation you can store for later use. Is it possible to do something like I want here? Or am I better off just making each operation function explicitly look at its input queue, and explicitly place values on the output queue?

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  • Why Does Private Access Remain Non-Private in .NET Within a Class?

    - by AMissico
    While cleaning some code today written by someone else, I changed the access modifier from Public to Private on a class variable/member/field. I expected a long list of compiler errors that I use to "refactor/rework/review" the code that used this variable. Imagine my surprise when I didn't get any errors. After reviewing, it turns out that another instance of the Class can access the private members of another instance declared within the Class. Totally unexcepted. Is this normal? I been coding in .NET since the beginning and never ran into this issue, nor read about it. I may have stumbled onto it before, but only "vaguely noticed" and move on. Can anyone explain this behavoir to me? Am I doing something wrong? I found this behavior in both C# and VB.NET. The code seems to take advantage of the ability to access private variables. Sincerely, Totally Confused Class Foo Private _int As Integer Private _foo As Foo Private _jack As Jack Private _fred As Fred Public Sub SetPrivate() _foo = New Foo _foo._int = 3 'TOTALLY UNEXPECTED _jack = New Jack '_jack._int = 3 'expected compile error because Foo doesn't know Jack _fred = New Fred '_fred._int = 3 'expected compile error because Fred hides from Foo End Sub Private Class Fred Private _int As Integer End Class End Class Class Jack Private _int As Integer End Class

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  • C++: parsing with simple regular expression or shoud I use sscanf?

    - by Helltone
    I need to parse a string like func1(arg1, arg2); func2(arg3, arg4);. It's not a very complex parsing problem, so I would prefer to avoid resorting to flex/bison or similar utilities. My first approch was to try to use POSIX C regcomp/regexec or Boost implementation of C++ std::regex. I wrote the following regular expression, which does not work (I'll explain why further on). "^" "[ ;\t\n]*" "(" // (1) identifier "[a-zA-Z_][a-zA-Z0-9_]*" ")" "[ \t\n]*" "(" // (2) non-marking "\[" "(" // (3) non-marking "[ \t]*" "(" // (4..n-1) argument "[a-zA-Z0-9_]+" ")" "[ \t\n]*" "," ")*" "[ \t\n]*" "(" // (n) last argument "[a-zA-Z0-9_]+" ")" "]" ")?" "[ \t\n]*" ";" Note that the group 1 captures the identifier and groups 4..n-1 are intended to capture arguments except the last, which is captured by group n. When I apply this regex to, say func(arg1, arg2, arg3) the result I get is an array {func, arg2, arg3}. This is wrong because arg1 is not in it! The problem is that in the standard regex libraries, submarkings only capture the last match. In other words, if you have for instance the regex "((a*|b*))*" applied on "babb", the results of the inner match will be bb and all previous captures will have been forgotten. Another thing that annoys me here is that in case of error there is no way to know which character was not recognized as these functions provide very little information about the state of the parser when the input is rejected. So I don't know if I'm missing something here... In this case should I use sscanf or similar instead? Note that I prefer to use C/C++ standard libraries (and maybe boost).

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  • Wrapper Classes for Backward compatibility in Java

    - by Casebash
    There is an interesting article here on maintaing backwards compatibility for Java. In the wrapper class section, I can't actually understand what the wrapper class accomplishes. In the following code from MyApp, WrapNewClass.checkAvailable() could be replaced by Class.forName("NewClass"). static { try { WrapNewClass.checkAvailable(); mNewClassAvailable = true; } catch (Throwable ex) { mNewClassAvailable = false; } } Consider when NewClass is unavailable. In the code where we use the wrapper (see below), all we have done is replace a class that doesn't exist, with one that exists, but which can't be compiled as it uses a class that doesn't exist. public void diddle() { if (mNewClassAvailable) { WrapNewClass.setGlobalDiv(4); WrapNewClass wnc = new WrapNewClass(40); System.out.println("newer API is available - " + wnc.doStuff(10)); }else { System.out.println("newer API not available"); } } Can anyone explain why this makes a difference? I assume it has something to do with how Java compiles code - which I don't know much about.

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  • Protecting Content with AuthLogic

    - by Rob Wilkerson
    I know this sounds like a really, really simple use case and I'm hoping that it is, but I swear I've looked all over the place and haven't found any mention of any way - not even the best way - of doing this. I'm brand-spanking new to Ruby, Rails and everything surrounding either (which may explain a lot). The dummy app that I'm using as my learning tool requires authentication in order to do almost anything meaningful, so I chose to start by solving that problem. I've installed the AuthLogic gem and have it working nicely to the extent that is covered by the intro documentation and Railscast, but now that I can register, login and logout...I need to do something with it. As an example, I need to create a page where users can upload images. I'm planning to have an ImagesController with an upload action method, but I want that only accessible to logged in users. I suppose that in every restricted action I could add code to redirect if there's no current_user, but that seems really verbose. Is there a better way of doing this that allows me to define or identify restricted areas and handle the authentication check in one place?

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  • ArrayList<Int> Collections.Sort and LineNumberReader Help How to

    - by user1819551
    I have a issue i can't get it to work now let going to the point a explain in the code thanks. This is my class: what I want to do is insert the Integers sort the list and buffer writer in a column with out coma. Now I getting this: [1110018, 1110032, 1110056, 1110059, 1110063, 1110085, 1110096, 1110123, 1110125, 1110185, 1110456, 1110459] I want like this: 111xxxxx 111xxxx xxxx....... I can't do it in single array, have to be in ArrayList. This is my collecting: list.addNumbers(numbers); list.display(); This is my writer: Is buffered coma.write("\n"+list.display()); coma.flush();<br/> Here is my class: public class IdCount {<br/> private ArrayList<Integer> properNumber = new ArrayList<>(); public void addNumbers(Integer numbers) { properNumber.add(numbers); Collections.sort(properNumber); } public String display() { //(I try .toString() Not work) return properNumber.toString(); } My second issue is LineNumberReader: This is my collecting and my writing: try { Reader input = new BufferedReader( new FileReader(inputFile)); try (Scanner in = new Scanner(input)) { while (in.hasNext()) { //(More Code) asp = new LineNumberReader(input); int rom = 0; while (asp.readLine()!=null){ rom++; } System.out.println(rom); coma.write(rom); This one will not write anything an my System Print give me only 12 0 in column.

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  • Career day in kindergarten

    - by Péter Török
    I was invited to the kindergarten group of my elder daughter to talk and answer the kids' questions about my profession. There are 26 kids of age 4-6 in the group, plus 3 teachers who are fairly scared of anything related to programming and IT themselves, but bold enough to learn new tricks. I would have about 20-30 minutes, without projector or anything. They have an old computer though, which by its look may be a 486, and I am not even sure if it's functioning. My research turned up excellent earlier threads, with lots of good tips: How would you explain your job to a 5-year old? Career Day: how do I make “computer programmer” sound cool to 8 year olds? What things can I teach a group of children about programming in one day? My situation is different from each of the above though: the latter ones are concerned with older children, while the first one is about talking to a single kid (or elder person)—a group of 20 is a whole different challenge. How can I teach the kids and their teachers about programming in a fun way?

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  • string maniupulations, oops, how do I replace parts of a string

    - by Joe Gibson
    I am very new to python. Could someone explain how I can manipulate a string like this? This function receives three inputs: complete_fmla: has a string with digits and symbols but has no hyphens ('-') nor spaces. partial_fmla: has a combination of hyphens and possibly some digits or symbols, where the digits and symbols that are in it (other than hyphens) are in the same position as in the complete_formula. symbol: one character The output that should be returned is: If the symbol is not in the complete formula, or if the symbol is already in the partial formula, the function should return the same formula as the input partial_formula. If the symbol is in the complete_formula and not in the partial formula, the function should return the partial_formula with the symbol substituting the hyphens in the positions where the symbol is, in all the occurrences of symbol in the complete_formula. For example: generate_next_fmla (‘abcdeeaa’, ‘- - - - - - - - ’, ‘d’) should return ‘- - - d - - - -’ generate_next_fmla (‘abcdeeaa’, ‘- - - d - - - - ’, ‘e’) should return ‘- - - d e e - -’ generate_next_fmla (‘abcdeeaa’, ‘- - - d e e - - ’, ‘a’) should return ‘a - - d e e a a’ Basically, I'm working with the definition: def generate_next_fmla (complete_fmla, partial_fmla, symbol): Do I turn them into lists? and then append? Also, should I find out the index number for the symbol in the complete_fmla so that I know where to append it in the string with hyphens??

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  • P/Invoke declarations should not be safe-critical

    - by Bobrovsky
    My code imports following native methods: DeleteObject, GetFontData and SelectObject from gdi32.dll GetDC and ReleaseDC from user32.dll I want to run the code in full trust and medium trust environments (I am fine with exceptions being thrown when these imported methods are indirectly used in medium trust environments). When I run Code Analysis on the code I get warnings like: CA5122 P/Invoke declarations should not be safe-critical. P/Invoke method 'GdiFont.DeleteObject(IntPtr)' is marked safe-critical. Since P/Invokes may only be called by critical code, this declaration should either be marked as security critical, or have its annotation removed entirely to avoid being misleading. Could someone explain me (in layman terms) what does this warning really mean? I tried putting these imports in static SafeNativeMethods class as internal static methods but this doesn't make the warnings go away. I didn't try to put them in NativeMethods because after reading this article I am unsure that it's the right way to go because I don't want my code to be completely unusable in medium trust environments (I think this will be the consequence of moving imports to NativeMethods). Honestly, I am pretty much confused about the real meaning of the warning and consequences of different options to suppressing it. Could someone shed some light on all this? EDIT: My code target .NET 2.0 framework. Assembly is marked with [assembly: AllowPartiallyTrustedCallers] Methods are declared like this: [DllImport("gdi32")] internal static extern int DeleteObject(HANDLE hObject);

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  • Design: How to declare a specialized memory handler class

    - by Michael Dorgan
    On an embedded type system, I have created a Small Object Allocator that piggy backs on top of a standard memory allocation system. This allocator is a Boost::simple_segregated_storage< class and it does exactly what I need - O(1) alloc/dealloc time on small objects at the cost of a touch of internal fragmentation. My question is how best to declare it. Right now, it's scope static declared in our mem code module, which is probably fine, but it feels a bit exposed there and is also now linked to that module forever. Normally, I declare it as a monostate or a singleton, but this uses the dynamic memory allocator (where this is located.) Furthermore, our dynamic memory allocator is being initialized and used before static object initialization occurs on our system (as again, the memory manager is pretty much the most fundamental component of an engine.) To get around this catch 22, I added an extra 'if the small memory allocator exists' to see if the small object allocator exists yet. That if that now must be run on every small object allocation. In the scheme of things, this is nearly negligable, but it still bothers me. So the question is, is there a better way to declare this portion of the memory manager that helps decouple it from the memory module and perhaps not costing that extra isinitialized() if statement? If this method uses dynamic memory, please explain how to get around lack of initialization of the small object portion of the manager.

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  • Problem in Building mplsh-run in lshkit

    - by Yijinsei
    Hi guy, been trying out this for quite some time but I'm still unable to built mplsh-run from lshkit Not sure if this would help to explain my situation during the building process /tmp/cc17kth4.o: In function `lshkit::MultiProbeLshRecallTable::reset(lshkit::MultiProbeLshModel, unsigned int, double, double)': mplsh-run.cpp:(.text._ZN6lshkit24MultiProbeLshRecallTable5resetENS_18MultiProbeLshModelEjdd[lshkit::MultiProbeLshRecallTable::reset(lshkit::MultiProbeLshModel, unsigned int, double, double)]+0x230): undefined reference to `lshkit::MultiProbeLshModel::recall(double) const' /tmp/cc17kth4.o: In function `void lshkit::MultiProbeLshIndex<unsigned int>::query_recall<lshkit::TopkScanner<lshkit::Matrix<float>::Accessor, lshkit::metric::l2sqr<float> > >(float const*, float, lshkit::TopkScanner<lshkit::Matrix<float>::Accessor, lshkit::metric::l2sqr<float> >&) const': mplsh-run.cpp:(.text._ZNK6lshkit18MultiProbeLshIndexIjE12query_recallINS_11TopkScannerINS_6MatrixIfE8AccessorENS_6metric5l2sqrIfEEEEEEvPKffRT_[void lshkit::MultiProbeLshIndex<unsigned int>::query_recall<lshkit::TopkScanner<lshkit::Matrix<float>::Accessor, lshkit::metric::l2sqr<float> > >(float const*, float, lshkit::TopkScanner<lshkit::Matrix<float>::Accessor, lshkit::metric::l2sqr<float> >&) const]+0x2c4): undefined reference to `lshkit::MultiProbeLsh::genProbeSequence(float const*, std::vector<unsigned int, std::allocator<unsigned int> >&, unsigned int) const' /tmp/cc17kth4.o: In function `void lshkit::MultiProbeLshIndex<unsigned int>::query<lshkit::TopkScanner<lshkit::Matrix<float>::Accessor, lshkit::metric::l2sqr<float> > >(float const*, unsigned int, lshkit::TopkScanner<lshkit::Matrix<float>::Accessor, lshkit::metric::l2sqr<float> >&)': mplsh-run.cpp:(.text._ZN6lshkit18MultiProbeLshIndexIjE5queryINS_11TopkScannerINS_6MatrixIfE8AccessorENS_6metric5l2sqrIfEEEEEEvPKfjRT_[void lshkit::MultiProbeLshIndex<unsigned int>::query<lshkit::TopkScanner<lshkit::Matrix<float>::Accessor, lshkit::metric::l2sqr<float> > >(float const*, unsigned int, lshkit::TopkScanner<lshkit::Matrix<float>::Accessor, lshkit::metric::l2sqr<float> >&)]+0x4a): undefined reference to `lshkit::MultiProbeLsh::genProbeSequence(float const*, std::vector<unsigned int, std::allocator<unsigned int> >&, unsigned int) const' collect2: ld returned 1 exit status the command that i used to built mplsh-run is g++ -I./lshkit/include -L/usr/lib -lm -lgsl -lgslcblas -lboost_program_options-mt mplsh-run.cpp Do you guys have any clue on how I could solve this?

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  • Calculate location and number of intersections between multiple date/time ranges?

    - by Patricker
    I need to calculate the location of intersections between multiple date ranges, and the number of overlapping intersections. Then I need to show which date/time ranges overlap each of those intersecting sections. It is slightly more complicated than that so I'll do my best to explain by providing an example. I am working in VB.Net, but C# examples are acceptable as well as I work in both. We have several high risk tasks that involve the same system. Below I have three example jobs named HR1/2/3/4 with start and end date/times. HR1 {1/6/2010 10:00 - 1/6/2010 15:00} HR2 {1/6/2010 11:00 - 1/6/2010 18:00} HR3 {1/6/2010 12:00 - 1/6/2010 14:00} HR4 {1/6/2010 18:00 - 1/6/2010 20:00} What I want the end result to be is shown below. I am having trouble describing it any way but by example. HRE1 {1/6/2010 10:00 - 1/6/2010 11:00} - Intersects 1 {End Time Split 1, for readability only, not needed in solution} HRE1 {1/6/2010 11:00 - 1/6/2010 12:00} - Intersects 2 HRE2 {1/6/2010 11:00 - 1/6/2010 12:00} - Intersects 2 {End Time Split 2, for readability only, not needed in solution} HRE1 {1/6/2010 12:00 - 1/6/2010 14:00} - Intersects 3 HRE2 {1/6/2010 12:00 - 1/6/2010 14:00} - Intersects 3 HRE3 {1/6/2010 12:00 - 1/6/2010 14:00} - Intersects 3 {End Time Split 3, for readability only, not needed in solution} HRE1 {1/6/2010 14:00 - 1/6/2010 15:00} - Intersects 2 HRE2 {1/6/2010 14:00 - 1/6/2010 15:00} - Intersects 2 {End Time Split 4, for readability only, not needed in solution} HRE2 {1/6/2010 15:00 - 1/6/2010 18:00} - Intersects 1 {End Time Split 5, for readability only, not needed in solution} HR4 {1/6/2010 18:00 - 1/6/2010 20:00} - Intersects 1 Any help would be greatly appreciated.

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  • Adding <tr> from repeater's ItemDataBound Event

    - by nemiss
    My repeater's templates generate a table, where each item is a table row. When a very very specific condition is met (itemdata), I want to add an additional row to the table from this event. How can I do that? protected void rptData_ItemDataBound(object sender, RepeaterItemEventArgs e) { if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem) { bool tmp = bool.Parse(DataBinder.Eval(e.Item.DataItem, "somedata").ToString()); if (!tmp && e.Item.ItemIndex != 0) { //Add row after this item } } } I can use e.Item.Controls.Add() and add TableRow but for that I need to locate a table right? How can I solve that? UPDATE I will explain now why I need this: I am creating a sort of message board, where data entries are displayed in a tabled style. The first items in the table are "important" items after those items, i want to add this row. I could solved it using 2 repeaters, where the first repeater will be bounded to pinned items, and the second repeater will be bounded to refular items. But I don't want to have to repeaters nor I want to complex the business logic for separating the fetched data to pinned and not-pinned collection. I think the best opton is to do it "onfly", using one repeater and one datasource.

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  • Does unboxing just return a pointer to the value within the boxed object on the heap?

    - by Charles
    I this MSDN Magazine article, the author states (emphasis mine): Note that boxing always creates a new object and copies the unboxed value's bits to the object. On the other hand, unboxing simply returns a pointer to the data within a boxed object: no memory copy occurs. However, it is commonly the case that your code will cause the data pointed to by the unboxed reference to be copied anyway. I'm confused by the sentence I've bolded and the sentence that follows it. From everything else I've read, including this MSDN page, I've never before heard that unboxing just returns a pointer to the value on the heap. I was under the impression that unboxing would result in you having a variable containing a copy of the value on the stack, just as you began with. After all, if my variable contains "a pointer to the value on the heap", then I haven't got a value type, I've got a pointer. Can someone explain what this means? Was the author on crack? (There is at least one other glaring error in the article). And if this is true, what are the cases where "your code will cause the data pointed to by the unboxed reference to be copied anyway"? I just noticed that the article is nearly 10 years old, so maybe this is something that changed very early on in the life of .Net.

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  • Is there any danger in committing to a component library such as SmartGwt or Swing?

    - by Banang
    Since February this year I have been working on an app that's built using SmartGWT components. Generally, I find the components very nice to work with, and the fact that they're open source and free to use is just fantastic. However, I can't seem to shake the feeling that it's not a durable way of developing, but I can't quite explain why. Maybe it's because I know that any minute now the team developing it could decide to stop, which would leave me and my team in a bit of a pickle, but I'm sure there must be something more. I have been trying to find ways of explaining this feeling to myself, but to no avail. Therefore I turn to you, dear community, to ask if you can come up with a good reason why committing to building your app (that's supposed to be around for many more years to come) using a component library such as SmartGWT is a bad idea? Is there any reason I should just have developed the components myself? Or did I make the right choice when deciding not to reinvent the wheel and just go for what was readily available?

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