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  • How should I properly format this code?

    - by ct2k7
    Hi, I've a small issue here. I am using an if statement with UIAlertView and I have two situations, both result in UIAlertViews. However, in one situation, I want to dismiss just the UIAlertView, the other, I want the UIAlertView to be dismissed and view to return to root view. This code describes is: if([serverOutput isEqualToString:@"login.true"]){ [Alert dismissWithClickedButtonIndex:0 animated:YES]; [UIApplication sharedApplication].networkActivityIndicatorVisible = NO; UIAlertView *success = [[UIAlertView alloc] initWithTitle:@"Success" message:@"The transaction was a success!" delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:nil, nil]; [success show]; [success release]; } else { UIAlertView *failure = [[UIAlertView alloc] initWithTitle:@"Failure" message:@"The transaction failed. Contact sales operator!" delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:nil, nil]; [failure show]; [failure release]; } } -(void)alertView: (UIAlertView *)success clickedButtonAtIndex: (NSInteger)buttonIndex{ switch(buttonIndex) { case 0: { [self.navigationController popToRootViewControllerAnimated:YES]; } } } So, in both cases, they follow the above action, but obviously, that's not what I want. Any ideas on what I do here?

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  • SFINAE + sizeof = detect if expression compiles

    - by FredOverflow
    I just found out how to check if operator<< is provided for a type. template<class T> T& lvalue_of_type(); template<class T> T rvalue_of_type(); template<class T> struct is_printable { template<class U> static char test(char(*)[sizeof( lvalue_of_type<std::ostream>() << rvalue_of_type<U>() )]); template<class U> static long test(...); enum { value = 1 == sizeof test<T>(0) }; typedef boost::integral_constant<bool, value> type; }; Is this trick well-known, or have I just won the metaprogramming Nobel prize? ;) EDIT: I made the code simpler to understand and easier to adapt with two global function template declarations lvalue_of_type and rvalue_of_type.

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  • Linq2Sql: query - subquery optimisation

    - by Budda
    I have the following query: IList<InfrStadium> stadiums = (from sector in DbContext.sectors where sector.Type=typeValue select new InfrStadium(sector.TeamId) ).ToList(); and InfrStadium class constructor: private InfrStadium(int teamId) { IList<Sector> teamSectors = (from sector in DbContext.sectors where sector.TeamId==teamId select sector) .ToList<>(); ... work with data } Current implementation perform 1+n queries, where n - number of records fetched the 1st time. I want to optimize that. And another one I would love to do using 'group' operator in way like this: IList<InfrStadium> stadiums = (from sector in DbContext.sectors group sector by sector.TeamId into team_sectors select new InfrStadium(team_sectors.Key, team_sectors) ).ToList(); with appropriate constructor: private InfrStadium(int iTeamId, IEnumerable<InfrStadiumSector> eSectors) { IList<Sector> teamSectors = eSectors.ToList(); ... work with data } But attempt to launch query causes the following error: Expression of type 'System.Int32' cannot be used for constructor parameter of type 'System.Collections.Generic.IEnumerable`1[InfrStadiumSector]' Question 1: Could you please explain, what is wrong here, I don't understand why 'team_sectors' is applied as 'System.Int32'? I've tried to change query a little (replace IEnumerable with IQueryeable): IList<InfrStadium> stadiums = (from sector in DbContext.sectors group sector by sector.TeamId into team_sectors select new InfrStadium(team_sectors.Key, team_sectors.AsQueryable()) ).ToList(); with appropriate constructor: private InfrStadium(int iTeamId, IQueryeable<InfrStadiumSector> eSectors) { IList<Sector> teamSectors = eSectors.ToList(); ... work with data } In this case I've received another but similar error: Expression of type 'System.Int32' cannot be used for parameter of type 'System.Collections.Generic.IEnumerable1[InfrStadiumSector]' of method 'System.Linq.IQueryable1[InfrStadiumSector] AsQueryableInfrStadiumSector' Question 2: Actually, the same question: can't understand at all what is going on here... P.S. I have another to optimize query idea (describe here: Linq2Sql: query optimisation) but I would love to find a solution with 1 request to DB).

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  • PDFParsing & extracting the images only in iPhone application.

    - by sagar
    Hello - Every one. ** : My Query : ** I want to extract only images from entire pdf document. ( Using Objective C - for iPhone Application ) : My Efforts : I have gone through this link which has details regarding different operators of PDF Document. ( http://mail-archives.apache.org/mod_mbox/pdfbox-commits/200912.mbox/%[email protected]%3E ) I also studied this document - ( http://developer.apple.com/mac/library/documentation/GraphicsImaging/Conceptual/drawingwithquartz2d/dq_pdf_scan/dq_pdf_scan.html#//apple_ref/doc/uid/TP30001066-CH220-TPXREF101 ) I also have gone through entire document of PDFReference.pdf ( From original Adobe Site ) PDFReference.pdf (Adobe Document - says that - for image there are following operators ) q Q BI EI I have placed following table get the image myTable = CGPDFOperatorTableCreate(); CGPDFOperatorTableSetCallback(myTable, "q", arrayCallback2); CGPDFOperatorTableSetCallback(myTable, "TJ", arrayCallback); CGPDFOperatorTableSetCallback(myTable, "Tj", stringCallback); I have following arrayCallback2 method for getting image void arrayCallback2(CGPDFScannerRef inScanner, void *userInfo) { // how to extract image from this code // means I have tried too many different ways. following is incorrect way & not giving image // CGPDFStreamRef stream; // represents a sequence of bytes // if (CGPDFDictionaryGetStream (d, "BI", &stream)){ // CGPDFDataFormat t=CGPDFDataFormatJPEG2000; // CFDataRef data = CGPDFStreamCopyData (stream, &t); // } } above arrayCallback2 method is called for operator "q", But I don't know How to extract the image from it. In short. What should be the solution for extracting the images from the pdf documents? Thanks in advance for your kind help. Sagar kothari.

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  • Adding array to an object breaks the array

    - by DisgruntledGoat
    I have an array like this (output from print_r): Array ( [price] => 700.00 [room_prices] => Array ( [0] => [1] => [2] => [3] => [4] => ) [bills] => Array ( [0] => Gas ) ) I'm running a custom function to convert it to an object. Only the top-level should be converted, the sub-arrays should stay as arrays. The output comes out like this: stdClass Object ( [price] => 700.00 [room_prices] => Array ( [0] => Array ) [bills] => Array ( [0] => Array ) ) Here is my conversion function. All it does is set the value of each array member to an object: function array_to_object( $arr ) { $obj = new stdClass; if ( count($arr) == 0 ) return $obj; foreach ( $arr as $k=>$v ) $obj->$k = $v; return $obj; } I can't figure this out for the life of me!

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  • problem finding a header with a c++ makefile

    - by Max
    Hi. I've started working with my first makefile. I'm writing a roguelike in C++ using the libtcod library, and have the following hello world program to test if my environment's up and running: #include "libtcod.hpp" int main() { TCODConsole::initRoot(80, 50, "PartyHack"); TCODConsole::root->printCenter(40, 25, TCOD_BKGND_NONE, "Hello World"); TCODConsole::flush(); TCODConsole::waitForKeypress(true); } My project directory structure looks like this: /CppPartyHack ----/libtcod-1.5.1 # this is the libtcod root folder --------/include ------------libtcod.hpp ----/PartyHack --------makefile --------partyhack.cpp # the above code (while we're here, how do I do proper indentation? Using those dashes is silly.) and here's my makefile: SRCDIR = . INCDIR = ../libtcod-1.5.1/include CFLAGS = $(FLAGS) -I$(INCDIR) -I$(SRCDIR) -Wall CC = gcc CPP = g++ .SUFFIXES: .o .h .c .hpp .cpp $(TEMP)/%.o : $(SRCDIR)/%.cpp $(CPP) $(CFLAGS) -o $@ -c $< $(TEMP)/%.o : $(SRCDIR)/%.c $(CC) $(CFLAGS) -o $@ -c $< CPP_OBJS = $(TEMP)partyhack.o all : partyhack partyhack : $(CPP_OBJS) $(CPP) $(CPP_OBJS) -o $@ -L../libtcod-1.5.1 -ltcod -ltcod++ -Wl,-rpath,. clean : \rm -f $(CPP_OBJS) partyhack I'm using Ubuntu, and my terminal gives me the following errors: max@max-desktop:~/Desktop/Development/CppPartyhack/PartyHack$ make g++ -c -o partyhack.o partyhack.cpp partyhack.cpp:1:23: error: libtcod.hpp: No such file or directory partyhack.cpp: In function ‘int main()’: partyhack.cpp:5: error: ‘TCODConsole’ has not been declared partyhack.cpp:6: error: ‘TCODConsole’ has not been declared partyhack.cpp:6: error: ‘TCOD_BKGND_NONE’ was not declared in this scope partyhack.cpp:7: error: ‘TCODConsole’ has not been declared partyhack.cpp:8: error: ‘TCODConsole’ has not been declared make: * [partyhack.o] Error 1 So obviously, the makefile can't find libtcod.hpp. I've double checked and I'm sure the relative path to libtcod.hpp in INCDIR is correct, but as I'm just starting out with makefiles, I'm uncertain what else could be wrong. My makefile is based off a template that the libtcod designers provided along with the library itself, and while I've looked at a few online makefile tutorials, the code in this makefile is a good bit more complicated than any of the examples the tutorials showed, so I'm assuming I screwed up something basic in the conversion. Thanks for any help.

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  • How to convert string with double high/wide characters to normal string [VC++6]

    - by Shaitan00
    My application typically recieves a string in the following format: " Item $5.69 " Some contants I always expect: - the LENGHT always 20 characters - the start index of the text always [5] - and most importantly the index of the DECIMAL for the price always [14] In order to identify this string correctly I validate all the expected contants listed above .... Some of my clients have now started sending the string with Doube-High / Double-Wide values (pair of characters which represent a single readable character) similar to the following: " Item $x80x90.x81x91x82x92 " For testing I simply scan the string character-by-character, compare char[i] and char[i+1] and replace these pairs with their corresponding single character when a match is found (works fine) as follows: [Code] for (int i=0; i < sData.length(); i++) { char ch = sData[i] & 0xFF; char ch2 = sData[i+1] & 0xFF; if (ch == '\x80' && ch2 == '\x90') zData.replace("\x80\x90", "0"); else if (ch == '\x81' && ch2 == '\x91') zData.replace("\x81\x91", "1"); else if (ch == '\x82' && ch2 == '\x92') zData.replace("\x82\x92", "2"); ... ... ... } [/Code] But the result is something like this: " Item $5.69 " Notice how this no longer matches my expectation: the lenght is now 17 (instead of 20) due to the 3 conversions and the decimal is now at index 13 (instead of 14) due to the conversion of the "5" before the decimal point. Ideally I would like to convert the string to a normal readable format keeping the constants (length, index of text, index of decimal) at the same place (so the rest of my application is re-usable) ... or any other suggestion (I'm pretty much stuck with this)... Is there a STANDARD way of dealing with these type of characters? Any help would be greatly appreciated, I've been stuck on this for a while now ... Thanks,

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  • Get the equivalent time between "dynamic" time zones

    - by doctore
    I have a table providers that has three columns (containing more columns but not important in this case): starttime, start time in which you can contact him. endtime, final hour in which you can contact him. region_id, region where the provider resides. In USA: California, Texas, etc. In UK: England, Scotland, etc starttime and endtime are time without timezone columns, but, "indirectly", their value has time zone of the region in which the provider resides. For example: starttime | endtime | region_id (time zone of region) | "real" st | "real" et ----------|----------|---------------------------------|-----------|----------- 03:00:00 | 17:00:00 | 1 (EGT => -1) | 02:00:00 | 16:00:00 Often I need to get the list of suppliers whose time range is within the current server time (taking into account the time zone conversion). The problem is that the time zones aren't "constant", ie, they may change during the summer time. However, this change is very specific to the region and not always carried out at the same time: EGT <= EGST, ART <= ARST, etc. The question is: 1. Is it necessary to use a webservice to update every so often the time zones in the regions? Does anyone know of a web service that can serve? 2. Is there a better approach to solve this problem? Thanks in advance. UPDATE I will give an example to clarify what I'm trying to get. In the table providers I found this records: idproviders | starttime | endtime | region_id ------------|-----------|----------|----------- 1 | 03:00:00 | 17:00:00 | 23 (Texas) 2 | 04:00:00 | 18:00:00 | 23 (Texas) If I execute the query in January, with this information: Server time (UTC offset) = 0 hours Texas providers (UTC offset) = +1 hour Server time = 02:00:00 I should get the following results: idproviders = 1 If I execute the query in June, with this information: Server time (UTC offset) = 0 hours Texas providers (UTC offset) = +2 hours (their local time has not changed, but their time zone has changed) Server time = 02:00:00 I should get the following results: idproviders = 1 and 2

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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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  • PHP/MySQL time zone migration

    - by El Yobo
    I have an application that currently stores timestamps in MySQL DATETIME and TIMESTAMP values. However, the application needs to be able to accept data from users in multiple time zones and show the timestamps in the time zone of other users. As such, this is how I plan to amend the application; I would appreciate any suggestions to improve the approach. Database modifications All TIMESTAMPs will be converted to DATETIME values; this is to ensure consistency in approach and to avoid having MySQL try to do clever things and convert time zones (I want to keep the conversion in PHP, as it involves less modification to the application, and will be more portable when I eventually manage to escape from MySQL). All DATETIME values will be adjusted to convert them to UTC time (currently all in Australian EST) Query modifications All usage of NOW() to be replaced with UTC_TIMESTAMP() in queries, triggers, functions, etc. Application modifications The application must store the time zone and preferred date format (e.g. US vs the rest of the world) All timestamps will be converted according to the user settings before being displayed All input timestamps will be converted to UTC according to the user settings before being input Additional notes Converting formats will be done at the application level for several main reasons The approach to converting time zones varies from DB to DB, so handing it there will be non-portable (and I really hope to be migrating away from MySQL some time in the not-to-distant future). MySQL TIMESTAMPs have limited ranges to the permitted dates (~1970 to ~2038) MySQL TIMESTAMPs have other undesirable attributes, including bizarre auto-update behaviour (if not carefully disabled) and sensitivity to the server zone settings (and I suspect I might screw these up when I migrate to Amazon later in the year). Is there anything that I'm missing here, or does anyone have better suggestions for the approach?

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  • Execute a function to affect different template class instances

    - by Samer Afach
    I have a complicated problem, and I need help. I have a base case, class ParamBase { string paramValue; //... } and a bunch of class templates with different template parameters. template <typename T> class Param : public ParamBase { T value; //... } Now, each instance of Param has different template parameter, double, int, string... etc. To make it easier, I have a vector to their base class pointers that contains all the instances that have been created: vector<ParamBase*> allParamsObjects; The question is: How can I run a single function (global or member or anything, your choice), that converts all of those different instances' strings paramValue with different templates arguments and save the conversion result to the appropriate type in Param::value. This has to be run over all objects that are saved in the vector allParamsObjects. So if the template argument of the first Param is double, paramValue has to be converted to double and saved in value; and if the second Param's argument is int, then the paramValue of the second has to be converted to int and saved in value... etc. I feel it's almost impossible... Any help would be highly appreciated :-)

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  • Using entity framework to connect to multiple similar tables in .net MVC.

    - by Dite
    A relative newcomer to .net MVC2 and the entity framework, I am working on a project which requires a single web application, (C# .net 4), to connect to multiple different databases depending on the route of access, (ie subdomain). No problem with this in principle and all the logic is written to transform the subdomain into an entity connection and pass this through to the Entity Model. The problem comes with the fact that the different database whilst being largely similar in structure contain 3 or 4 unique tables bespoke to that instance. To my mind there are two ways to solve this issue, neither of which i am sure will be possible. 1/ Use a separate entity model for each database. -Attempts down this route have through up conflicts where table/sp names are the same across differnt db's, or implicit conversion errors when I try and put the different models in different namespaces. or 2/ Overwrite the classes which refer to the changeable database objects based on the value of a base controller property. -I have found nothing to suggest i can even do this. My question is if either of theser routes can ever work in principle or if i should just give up on the EF and connect to the dtabases directlky using ADO. Perhaps there is another way to solve this problem i haven't thought of? Thanks for any help...

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  • C++ Matrix class hierachy

    - by bpw1621
    Should a matrix software library have a root class (e.g., MatrixBase) from which more specialized (or more constrained) matrix classes (e.g., SparseMatrix, UpperTriangluarMatrix, etc.) derive? If so, should the derived classes be derived publicly/protectively/privately? If not, should they be composed with a implementation class encapsulating common functionality and be otherwise unrelated? Something else? I was having a conversation about this with a software developer colleague (I am not per se) who mentioned that it is a common programming design mistake to derive a more restricted class from a more general one (e.g., he used the example of how it was not a good idea to derive a Circle class from an Ellipse class as similar to the matrix design issue) even when it is true that a SparseMatrix "IS A" MatrixBase. The interface presented by both the base and derived classes should be the same for basic operations; for specialized operations, a derived class would have additional functionality that might not be possible to implement for an arbitrary MatrixBase object. For example, we can compute the cholesky decomposition only for a PositiveDefiniteMatrix class object; however, multiplication by a scalar should work the same way for both the base and derived classes. Also, even if the underlying data storage implementation differs the operator()(int,int) should work as expected for any type of matrix class. I have started looking at a few open-source matrix libraries and it appears like this is kind of a mixed bag (or maybe I'm looking at a mixed bag of libraries). I am planning on helping out with a refactoring of a math library where this has been a point of contention and I'd like to have opinions (that is unless there really is an objective right answer to this question) as to what design philosophy would be best and what are the pros and cons to any reasonable approach.

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  • How do I send floats in window messages.

    - by yngvedh
    Hi, What is the best way to send a float in a windows message using c++ casting operators? The reason I ask is that the approach which first occurred to me did not work. For the record I'm using the standard win32 function to send messages: PostWindowMessage(UINT nMsg, WPARAM wParam, LPARAM lParam) What does not work: Using static_cast<WPARAM>() does not work since WPARAM is typedef'ed to UINT_PTR and will do a numeric conversion from float to int, effectively truncating the value of the float. Using reinterpret_cast<WPARAM>() does not work since it is meant for use with pointers and fails with a compilation error. I can think of two workarounds at the moment: Using reinterpret_cast in conjunction with the address of operator: float f = 42.0f; ::PostWindowMessage(WM_SOME_MESSAGE, *reinterpret_cast<WPARAM*>(&f), 0); Using an union: union { WPARAM wParam, float f }; f = 42.0f; ::PostWindowMessage(WM_SOME_MESSAGE, wParam, 0); Which of these are preffered? Are there any other more elegant way of accomplishing this?

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  • convert variable with mixed date formats to one format in r

    - by jalapic
    A sample of my dataframe: date 1 25 February 1987 2 20 August 1974 3 9 October 1984 4 18 August 1992 5 19 September 1995 6 16-Oct-63 7 30-Sep-65 8 22 Jan 2008 9 13-11-1961 10 18 August 1987 11 15-Sep-70 12 5 October 1994 13 5 December 1984 14 03/23/87 15 30 August 1988 16 26-10-1993 17 22 August 1989 18 13-Sep-97 I have a large dataframe with a date variable that has multiple formats for dates. Most of the formats in the variable are shown above- there are a couple of very rare others too. The reason why there are multiple formats is that the data were pulled together from various websites that each used different formats. I have tried using straightforward conversions e.g. strftime(mydf$date,"%d/%m/%Y") but these sorts of conversion will not work if there are multiple formats. I don't want to resort to multiple gsub type editing. I was wondering if I am missing a more simple solution? Code for example: structure(list(date = structure(c(12L, 8L, 18L, 6L, 7L, 4L, 14L, 10L, 1L, 5L, 3L, 17L, 16L, 11L, 15L, 13L, 9L, 2L), .Label = c("13-11-1961", "13-Sep-97", "15-Sep-70", "16-Oct-63", "18 August 1987", "18 August 1992", "19 September 1995", "20 August 1974", "22 August 1989", "22 Jan 2008", "03/23/87", "25 February 1987", "26-10-1993", "30-Sep-65", "30 August 1988", "5 December 1984", "5 October 1994", "9 October 1984"), class = "factor")), .Names = "date", row.names = c(NA, -18L), class = "data.frame")

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  • [C++] My First Go With Function Templates

    - by bobber205
    Thought it was pretty straight forward. But I get a "iterator not dereferencable" errro when running the below code. What's wrong? template<typename T> struct SumsTo : public std::binary_function<T, T, bool> { int myInt; SumsTo(int a) { myInt = a; } bool operator()(const T& l, const T& r) { cout << l << " + " << r; if ((l + r) == myInt) { cout << " does add to " << myInt; } else { cout << " DOES NOT add to " << myInt; } return true; } }; void main() { list<int> l1; l1.push_back(1); l1.push_back(2); l1.push_back(3); l1.push_back(4); list<int> l2; l2.push_back(9); l2.push_back(8); l2.push_back(7); l2.push_back(6); transform(l1.begin(), l1.end(), l2.begin(), l2.end(), SumsTo<int>(10) ); }

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  • JRuby app throws exception in Spring

    - by mat3001
    I am trying to run a JRuby app in Spring. I use Eclipse to run it. But it doesn't compile. Does anybody know what's going on here? Exception in thread "Launcher:/oflaDemo" [INFO] [Launcher:/oflaDemo] org.springframework.beans.factory.support.DefaultListableBeanFactory - Destroying singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@4a009ab0: defining beans [placeholderConfig,web.context,web.scope,web.handler,demoService.service]; parent: org.springframework.beans.factory.support.DefaultListableBeanFactory@f5d8d75 [INFO] [Launcher:/installer] org.red5.server.service.Installer - Installer service created org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'web.scope' defined in ServletContext resource [/WEB-INF/red5-web.xml]: Initialization of bean failed; nested exception is org.springframework.beans.TypeMismatchException: Failed to convert property value of type [org.springframework.scripting.jruby.JRubyScriptFactory] to required type [org.red5.server.api.IScopeHandler] for property 'handler'; nested exception is java.lang.IllegalArgumentException: Cannot convert value of type [org.springframework.scripting.jruby.JRubyScriptFactory] to required type [org.red5.server.api.IScopeHandler] for property 'handler': no matching editors or conversion strategy found at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:480) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory$1.run(AbstractAutowireCapableBeanFactory.java:409) at java.security.AccessController.doPrivileged(Native Method) I don't have a lot of experience with Spring, so I would really appreciate hits. If you're familiar with red5 - yes it's the oflademo app supplied by red5.

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  • Combining two data sets and plotting in matlab

    - by bautrey
    I am doing experiments with different operational amplifier circuits and I need to plot my measured results onto a graph. I have two data sets: freq1 = [.1 .2 .5 .7 1 3 4 6 10 20 35 45 60 75 90 100]; %kHz Vo1 = [1.2 1.6 1.2 2 2 2.4 14.8 20.4 26.4 30.4 53.6 68.8 90 114 140 152]; %mV V1 = 19.6; Acm = Vo1/(1000*V1); And: freq2 = [.1 .5 1 30 60 70 85 100]; %kHz Vo1 = [3.96 3.96 3.96 3.84 3.86 3.88 3.88 3.88]; %V V1 = .96; Ad = Vo1/(2*V1); (I would show my plots but apparently I need more reps for that) I need to plot the equation, CMRR vs freq: CMRR = 20*log10(abs(Ad/Acm)); The size of Ad and Acm are different and the frequency points do not match up, but the boundaries of both of these is the same, 100Hz to 100kHz (x-axis). On the line of CMRR, Matlab says that Ad and Acm matrix dimensions do not agree. How I think I would solve this is using freq1 as the x-axis for CMRR and then taking approximated points from Ad according to the value on freq1. Or I could do function approximations of Ad and Acm and then do the divide operator on those. I do not know how I would code up this two ideas. Any other ideas would helpful, especially simpler ones. Thanks

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  • Solved: Help with this compile error

    - by Scott
    I just picked up an old project and I'm not sure what the following error could mean. g++ -o BufferedReader.o -c -g -Wall -std=c++0x -I/usr/include/xmms2 -Ijsoncpp/include/json/ -fopenmp -I/usr/include/ImageMagick -I/usr/include/xmms2 -I/usr/include/libvisual-0.4 -D_GNU_SOURCE=1 -D_REENTRANT -I/usr/include/SDL -DQT_CORE_LIB -DQT_GUI_LIB -DQT_SCRIPT_LIB -DQT_SHARED -I/usr/include/QtCore -I/usr/include/QtGui -I/usr/include/QtScript BufferedReader.cpp In file included from BufferedReader.cpp:23: /usr/include/string.h:36:42: error: missing binary operator before token "(" In file included from /usr/lib/gcc/i686-redhat-linux/4.4.3/../../../../include/c++/4.4.3/cwchar:47, from /usr/lib/gcc/i686-redhat-linux/4.4.3/../../../../include/c++/4.4.3/bits/postypes.h:42, from /usr/lib/gcc/i686-redhat-linux/4.4.3/../../../../include/c++/4.4.3/iosfwd:42, from /usr/lib/gcc/i686-redhat-linux/4.4.3/../../../../include/c++/4.4.3/ios:39, from /usr/lib/gcc/i686-redhat-linux/4.4.3/../../../../include/c++/4.4.3/istream:40, from /usr/lib/gcc/i686-redhat-linux/4.4.3/../../../../include/c++/4.4.3/sstream:39, from BufferedReader.cpp:24: At line 24 of BufferedReader.cpp is #include <string.h>. I've tried it with just <string> but get the same thing. Any clue? Here's the snippet of code from string.h /* Tell the caller that we provide correct C++ prototypes. */ #if defined __cplusplus && __GNUC_PREREQ (4, 4) //line 36 # define __CORRECT_ISO_CPP_STRING_H_PROTO #endif Does that mean __GNUC_PREREQ isn't defined? Edit: Changing -Ijsoncpp/include/json/ to Ijsoncpp/include stopped the errors. I noticed I was including <json/json.h>. I'm about to switch to JsonGlib though, which is the reason I pulled the project up again. So it's all good. :)

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  • Suggestions for a django db structure

    - by rh0dium
    Hi Say I have the unknown number of questions. For example: Is the sky blue [y/n] What date were your born on [date] What is pi [3.14] What is a large integ [100] Now each of these questions poses a different but very type specific answer (boolean, date, float, int). Natively django can happily deal with these in a model. class SkyModel(models.Model): question = models.CharField("Is the sky blue") answer = models.BooleanField(default=False) class BirthModel(models.Model): question = models.CharField("What date were your born on") answer = models.DateTimeField(default=today) class PiModel(models.Model) question = models.CharField("What is pi") answer = models.FloatField() But this has the obvious problem in that each question has a specific model - so if we need to add a question later I have to change the database. Yuck. So now I want to get fancy - How do a set up a model where by the answer type conversion happens automagically? ANSWER_TYPES = ( ('boolean', 'boolean'), ('date', 'date'), ('float', 'float'), ('int', 'int'), ('char', 'char'), ) class Questions(models.model): question = models.CharField(() answer = models.CharField() answer_type = models.CharField(choices = ANSWER_TYPES) default = models.CharField() So in theory this would do the following: When I build up my views I look at the type of answer and ensure that I only put in that value. But when I want to pull that answer back out it will return the data in the format specified by the answer_type. Example 3.14 comes back out as a float not as a str. How can I perform this sort of automagic transformation? Or can someone suggest a better way to do this? Thanks much!!

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  • Simple matrix example using C++ template class

    - by skyeagle
    I am trying to write a trivial Matrix class, using C++ templates in an attempt to brush up my C++, and also to explain something to a fellow coder. This is what I have som far: template class<T> class Matrix { public: Matrix(const unsigned int rows, const unsigned int cols); Matrix(const Matrix& m); Matrix& operator=(const Matrix& m); ~Matrix(); unsigned int getNumRows() const; unsigned int getNumCols() const; template <class T> T getCellValue(unsigned int row, unsigned col) const; template <class T> void setCellValue(unsigned int row, unsigned col, T value) const; private: // Note: intentionally NOT using smart pointers here ... T * m_values; }; template<class T> inline T Matrix::getCellValue(unsigned int row, unsigned col) const { } template<class T> inline void Matrix::setCellValue(unsigned int row, unsigned col, T value) { } I'm stuck on the ctor, since I need to allocate a new[] T, it seems like it needs to be a template method - however, I'm not sure I have come accross a templated ctor before. How can I implemnt the ctor?

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  • Is memory allocation in linux non-blocking?

    - by Mark
    I am curious to know if the allocating memory using a default new operator is a non-blocking operation. e.g. struct Node { int a,b; }; ... Node foo = new Node(); If multiple threads tried to create a new Node and if one of them was suspended by the OS in the middle of allocation, would it block other threads from making progress? The reason why I ask is because I had a concurrent data structure that created new nodes. I then modified the algorithm to recycle the nodes. The throughput performance of the two algorithms was virtually identical on a 24 core machine. However, I then created an interference program that ran on all the system cores in order to create as much OS pre-emption as possible. The throughput performance of the algorithm that created new nodes decreased by a factor of 5 relative the the algorithm that recycled nodes. I'm curious to know why this would occur. Thanks. *Edit : pointing me to the code for the c++ memory allocator for linux would be helpful as well. I tried looking before posting this question, but had trouble finding it.

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  • C++ Suppress Automatic Initialization and Destruction

    - by Travis G
    How does one suppress the automatic initialization and destruction of a type? While it is wonderful that T buffer[100] automatically initializes all the elements of buffer, and destroys them when they fall out of scope, this is not the behavior I want. #include <iostream> static int created = 0, destroyed = 0; struct S { S() { ++created; } ~S() { ++destroyed; } }; template <typename T, size_t KCount> class Array { private: T m_buffer[KCount]; public: Array() { // some way to suppress the automatic initialization of m_buffer } ~Array() { // some way to suppress the automatic destruction of m_buffer } }; int main() { { Array<S, 100> arr; } std::cout << "Created:\t" << created << std::endl; std::cout << "Destroyed:\t" << destroyed << std::endl; return 0; } The output of this program is: Created: 100 Destroyed: 100 I would like it to be: Created: 0 Destroyed: 0 My only idea is to make m_buffer some trivially constructed and destructed type like char and then rely on operator[] to wrap the pointer math for me, although this seems like a horribly hacked solution. Another solution would be to use malloc and free, but that gives a level of indirection that I do not want.

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  • why BOOST_FOREACH cannot handle const boost::ptr_map?

    - by psaghelyi
    void main() { typedef boost::ptr_map<int, char> MyMap; MyMap mymap; mymap[1] = 'a'; mymap[2] = 'b'; mymap[3] = 'c'; BOOST_FOREACH(MyMap::value_type value, mymap) { std::cout << value.first << " " << value.second << std::endl; } MyMap const & const_mymap = mymap; BOOST_FOREACH(MyMap::value_type value, const_mymap) { std::cout << value.first << " " << value.second << std::endl; } } The following error message comes from GCC at the second BOOST_FOREACH error: conversion from 'boost::ptr_container_detail::ref_pair<int, const char* const>' to non-scalar type 'boost::ptr_container_detail::ref_pair<int, char* const>' requested I reckon that this is the weakness of the pointer container's ref_pair...

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  • Casting Type array to Generic array?

    - by George R
    The short version of the question - why can't I do this? I'm restricted to .NET 3.5. T[] genericArray; // Obviously T should be float! genericArray = new T[3]{ 1.0f, 2.0f, 0.0f }; // Can't do this either, why the hell not genericArray = new float[3]{ 1.0f, 2.0f, 0.0f }; Longer version - I'm working with the Unity engine here, although that's not important. What is - I'm trying to throw conversion between its fixed Vector2 (2 floats) and Vector3 (3 floats) and my generic Vector< class. I can't cast types directly to a generic array. using UnityEngine; public struct Vector { private readonly T[] _axes; #region Constructors public Vector(int axisCount) { this._axes = new T[axisCount]; } public Vector(T x, T y) { this._axes = new T[2] { x, y }; } public Vector(T x, T y, T z) { this._axes = new T[3]{x, y, z}; } public Vector(Vector2 vector2) { // This doesn't work this._axes = new T[2] { vector2.x, vector2.y }; } public Vector(Vector3 vector3) { // Nor does this this._axes = new T[3] { vector3.x, vector3.y, vector3.z }; } #endregion #region Properties public T this[int i] { get { return _axes[i]; } set { _axes[i] = value; } } public T X { get { return _axes[0];} set { _axes[0] = value; } } public T Y { get { return _axes[1]; } set { _axes[1] = value; } } public T Z { get { return this._axes.Length (Vector2 vector2) { Vector vector = new Vector(vector2); return vector; } public static explicit operator Vector(Vector3 vector3) { Vector vector = new Vector(vector3); return vector; } #endregion }

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