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  • XCode GCC-4.0 vs 4.2

    - by John Smith
    I have just changed a compiler option from 4.0 to 4.2. Now I get an error: jump to case label crosses initialization of 'const char* selectorName' It works fine in 4.0 Any ideas?

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  • object_getInstanceVariable works for float, int, bool, but not for double?

    - by Russel West
    I've got object_getInstanceVariable to work as here however it seems to only work for floats, bools and ints not doubles. I do suspect I'm doing something wrong but I've been going in circles with this. float myFloatValue; float someFloat = 2.123f; object_getInstanceVariable(self, "someFloat", (void*)&myFloatValue); works, and myFloatValue = 2.123 but when I try double myDoubleValue; double someDouble = 2.123f; object_getInstanceVariable(self, "someDouble", (void*)&myDoubleValue); i get myDoubleValue = 0. If I try to set myDoubleValue before the function eg. double myDoubleValue = 1.2f, the value is unchanged when I read it after the object_getInstanceVariable call. setting myIntValue to some other value before the getinstancevar function above returns 2 as it should, ie. it has been changed. then I tried Ivar tmpIvar = object_getInstanceVariable(self, "someDouble", (void*)&myDoubleValue); if i do ivar_getName(tmpIvar) i get "someDouble", but myDoubuleValue = 0 still! then i try ivar_getTypeEncoding(tmpIvar) and i get "d" as it should be. So to summarize, if typeEncoding = float, it works, if it is a double, the result is not set but it correctly reads the variable and the return value (Ivar) is also correct. I must be doing something basic wrong that I cant see so I'd appreciate if someone could point it out.

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  • Why is my app running

    - by John Smith
    I have compiled my iPhone app with setting (Device, Release). I install it on the test machine and it runs with no problem. Here's the problem. The app is linked to a C++ library. The compilation on the simulator has no errors. However the device compilation produces 568 errors, mostly about different visibilities w.r.t AppDelegate.o. They all look like: QL::Error::~Error()has different visibility (default) in /QL/build/Release-iphoneos/libQLLibrary.a(abcd.o) and (hidden) in /Programming/ObjC/Second/build/Second.build/Release-iphoneos/FG.build/Objects-normal/armv6/AppDelegate.o Why is this, and how can I stop the errors anyway?

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  • Mac OS X linker error in Qt; CoreGraphics & CGWindowListCreate

    - by Jake Petroules
    Here is my .mm file #include "windowmanagerutils.h" #ifdef Q_OS_MAC #import </System/Library/Frameworks/ApplicationServices.framework/Frameworks/CoreGraphics.framework/Headers/CGWindow.h> QRect WindowManagerUtils::getWindowRect(WId windowId) { CFArrayRef windows = CGWindowListCreate(kCGWindowListOptionOnScreenOnly, kCGNullWindowID); return QRect(); } QRect WindowManagerUtils::getClientRect(WId windowId) { return QRect(); } QString WindowManagerUtils::getWindowText(WId windowId) { return QString(); } WId WindowManagerUtils::rootWindow() { QApplication::desktop()->winId(); } WId WindowManagerUtils::windowFromPoint(const QPoint &p, WId parent, bool(*filterFunction)(WId)) { return NULL; } void WindowManagerUtils::setTopMostCarbon(const QWidget *const window, bool topMost) { if (!window) { return; } // Find a Cocoa equivalent for this Carbon function // [DllImport("/System/Library/Frameworks/Carbon.framework/Versions/Current/Carbon")] // OSStatus ret = HIViewSetZOrder(this->winId(), kHIViewZOrderAbove, NULL); } #endif The linker is telling me "_CGWindowListCreate" is undefined. What libraries must I link to? Apple's documentation is not very helpful on telling what to include or link to, like MSDN is. Also I couldn't just do #import <CGWindow.h>, I had to specify the absolute path to it... any way around that?

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  • Dock tile plug-ins for not running applications

    - by kiamlaluno
    Is the dock tile plug-in of an application used even when the application is not active? The documentation says that the dock title plug-in is used when the application is loaded in the dock, but that means that the application is running of that the application is put in the dock because the user wants it to stay on the dock?

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  • Looking for marg_setValue in UIKit

    - by John Smith
    I am trying to compile a library originally written for Cocoa. Things are good until it looks for the function marg_setValue(). It says it can't find it. I have googled and found it is defined in How can I use this file in cocoa-touch? Or does cocoa-touch not support runtime.

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  • Looking for marg_setValue fix in iPhoneOS

    - by John Smith
    I am trying to compile a library originally written for Cocoa. Things are good until it looks for the function marg_setValue(). It says there is a syntax error before char in marg_setValue(argumentList,argumentOffset,char,(char)lua_toboolean(state,luaArgument)); (it's talking about the third argument, not (char) ) I am trying to port LuaObjectiveCBridge to the iPhone. It has two choices, either using Runtime or Foundation. I have discovered there are some problems with foundation so I am trying runtime. But the compiler is not co-operating.

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  • Compare two Xcode build settings

    - by John Smith
    I have a project where I use two build settings predominantly. Unfortunately today something went wrong. One compiles and the other doesn't. How can I compare the two build settings in XCode to see what the differences are? (For those interested, the error I get in one build is jump to case label crosses initialization of 'const char* selectorName' if you know what this means I'll be very grateful )

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  • Returning from method inside a @synchronized block

    - by Michael Waterfall
    I'd just like to know if it's advised to return from a method within a @synchronized block? For example: - (id)test { @synchronized(self) { if (a) return @"A"; else return @"B"; } } As opposed to: - (id)test { NSString *value; @synchronized(self) { if (a) value = @"A"; else value = @"B"; } return value; } This sample is rather simplistic, but sometimes in a complex method it would make things simpler to be able to return from within a @synchronized block.

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  • Different results coming out of an init method than those expected. Why does this happen and how can

    - by Mark Reid
    When I run this method the two properties I have are set to (NULL) when I try and access them outside of the if statement. But they are set to 0 and NO if I check them inside the for loop. -(id) init { NSLog(@"Jumping into the init method!"); if (self = [super init]) { NSLog(@"Running the init method extras"); accumulator = 0; NSLog(@"self.accumulator is %g", accumulator); decimal = NO; } NSLog(@"Calc after init is: %@ and %@", self.accumulator, self.decimal); return self; } Any suggestions as to why what comes out is different from what's done in the for loop?

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  • C As Principal Class For Mac App

    - by CodaFi
    So, I've got a c file raring to go and be the main class behind an all-C mac-app, however, a combination of limiting factors are preventing the application from being launched. As it currently stands, the project is just a main.m and a class called AppDelegate.c, so I entered "AppDelegate" as the name of the principal class in the info.plist, and to my complete surprise, the log printed: Unable to find class: AppDelegate, exiting This would work perfectly well in iOS, because the main function accepts the name of a delegate class, and handles it automatically, but NSApplicationMain() takes no such argument. Now, I know this stems from the fact that there are no @interface/@implementation directives in C, and that's really what the OS seems to be looking for, so I wrote a simple NSApplication subclass and provided it as the Principal Class to the plist, and it launched perfectly well. My question is, how could one go about setting a c file as the principal class in a mac application and have it launch correctly? PS, don't ask what or why I'm doing this for, the foundation must be dug. For @millimoose's amusement, here be the AppDelegate.c file: #include <objc/runtime.h> #include <objc/message.h> struct AppDel { Class isa; id window; }; // This is a strong reference to the class of the AppDelegate // (same as [AppDelegate class]) Class AppDelClass; BOOL AppDel_didFinishLaunching(struct AppDel *self, SEL _cmd, void *application, void *options) { self->window = objc_msgSend(objc_getClass("NSWindow"), sel_getUid("alloc")); self->window = objc_msgSend(self->window, sel_getUid("init")); objc_msgSend(self->window, sel_getUid("makeKeyAndOrderFront:"), self); return YES; }

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  • Call instance method with objc_msgSend

    - by user772349
    I'm trying to use the objc_msgSend method to call some method dynamically. Say I want call some method in Class B from Class A and there are two methods in class B like: - (void) instanceTestWithStr1:(NSString *)str1 str2:(NSString *)str1; + (void) methodTestWithStr1:(NSString *)str1 str2:(NSString *)str1; And I can call the class method like this in Class A successfully: objc_msgSend(objc_getClass("ClassB"), sel_registerName("methodTestWithStr1:str2:"), @"111", @"222"); And I can call the instance method like this in Class A successfully as well: objc_msgSend([[objc_getClass("ClassB") alloc] init], sel_registerName("instanceTestWithStr1:str2:"), @"111", @"222"); But the thing is to get a instance of Class B I have to call "initWithXXXXX:XXXXXX:XXXXXX" instead of "init" so that to pass some necessary parameters to class B to do the init stuff. So I stored a instance of ClassB in class A as variable: self.classBInstance = [[ClassB alloc] initWithXXXXX:XXXXXX:XXXXXX]; And then I call the method like this (successfully): The problem is, I want to call a method by simply applying the classname and the method sel like "ClassName" and "SEL" and then call it dynamically: If it's a class method. then call it like: objc_msgSend(objc_getClass("ClassName"), sel_registerName("SEL")); If it's a instance method, find the existing class instance variable in the calling class then: objc_msgSend([self.classInstance, sel_registerName("SEL")); So I want to know if there is any way to: Check if a class has a given method (I found "responseToSelector" will be the one) Check if a given method in class method or instance method (maybe can use responseToSelector as well) Check if a class has a instance variable of a given class So I can call a instance method like: objc_msgSend(objc_getClassInstance(self, "ClassB"), sel_registerName("SEL"));

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  • Add a hidden view above a UITableView that is only displayed when TableView is scrolled up

    - by noncogitas
    Goal/Situation: I currently have a UIView in the TableView header. I am trying to add another UIView (which contains two Buttons and a few TextFields) that will sit above the TableView header. I would like the view to be displayed when the user scrolls up past the header (a la "pull to refresh"), and go away when the user presses a "done" button on the view. My two questions: 1) How do I add a view above the tableview header? 2) How do I display said view when a user has scrolled up past the header? 3) How do I dismiss said view when the user has pressed a button on said view?

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  • objective-c uncompress/inflate a NSData object which contains a gzipped string

    - by user141146
    Hi, I'm using objective-c (iPhone) to read a sqlite table that contains blob data. The blob data is actually a gzipped string. The blob data is read into memory as an NSData object I then use a method (gzipInflate) which I grabbed from here (http://www.cocoadev.com/index.pl?NSDataCategory) -- see method below. However, the gzipInflate method is returning nil. If I step through the gzipInflate method, I can see that the status returned near the bottom of the method is -3, which I assume is some type of error (Z_STREAM_END = 1 and Z_OK = 0, but I don't know precisely what a status of -3 is). Consequently, the function returns nil even though the input NSData is 841 bytes in length. Any thoughts on what I'm doing wrong? Is there something wrong with the method? Something wrong with how I'm using the method? Any thoughts on how to test this? Thanks for any help! - (NSData *)gzipInflate { // NSData *compressed_data = [self.description dataUsingEncoding: NSUTF16StringEncoding]; NSData *compressed_data = self.description; if ([compressed_data length] == 0) return compressed_data; unsigned full_length = [compressed_data length]; unsigned half_length = [compressed_data length] / 2; NSMutableData *decompressed = [NSMutableData dataWithLength: full_length + half_length]; BOOL done = NO; int status; z_stream strm; strm.next_in = (Bytef *)[compressed_data bytes]; strm.avail_in = [compressed_data length]; strm.total_out = 0; strm.zalloc = Z_NULL; strm.zfree = Z_NULL; if (inflateInit2(&strm, (15+32)) != Z_OK) return nil; while (!done) { // Make sure we have enough room and reset the lengths. if (strm.total_out >= [decompressed length]) [decompressed increaseLengthBy: half_length]; strm.next_out = [decompressed mutableBytes] + strm.total_out; strm.avail_out = [decompressed length] - strm.total_out; // Inflate another chunk. status = inflate (&strm, Z_SYNC_FLUSH); NSLog(@"zstreamend = %d", Z_STREAM_END); if (status == Z_STREAM_END) done = YES; else if (status != Z_OK) break; //status here actually is -3 } if (inflateEnd (&strm) != Z_OK) return nil; // Set real length. if (done) { [decompressed setLength: strm.total_out]; return [NSData dataWithData: decompressed]; } else return nil; }

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  • Integers not properly returned from a property list (plist) array in Objective-C

    - by Gaurav
    In summary, I am having a problem where I read what I expect to be an NSNumber from an NSArray contained in a property list and instead of getting a number such as '1', I get what looks to be a memory address (i.e. '61879840'). The numbers are clearly correct in the property list. Below is my process for creating the property list and reading it back. Creating the property list I have created a simple Objective-C property list with arrays of integers within one root array: <array> <array> <integer>1</integer> <integer>2</integer> </array> <array> <integer>1</integer> <integer>2</integer> <integer>5</integer> </array> ... more arrays with integers ... </array> The arrays are NSArray objects and the integers are NSNumber objects. The property list has been created and serialized using the following code: // factorArray is an NSArray that contains NSArrays of NSNumbers as described above // serialize and compress factorArray as a property list, Factors-bin.plist NSString *error; NSString *rootPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0]; NSString *plistPath = [rootPath stringByAppendingPathComponent:@"Factors-bin.plist"]; NSData *plistData = [NSPropertyListSerialization dataFromPropertyList:factorArray format:NSPropertyListBinaryFormat_v1_0 errorDescription:&error]; Inspecting the created plist, all values and types are correct. Reading the property list The property list is read in as Data and then converted to an NSArray: NSString *path = [[NSBundle mainBundle] pathForResource:@"Factors" ofType:@"plist"]; NSData *plistData = [[NSData alloc] initWithContentsOfFile:path]; NSPropertyListFormat format; NSString *error = nil; NSArray *factorData = (NSArray *)[NSPropertyListSerialization propertyListFromData:plistData mutabilityOption:NSPropertyListImmutable format:&format errorDescription:&error]; Cycling through factorData to see what it contains is where I see the erroneous integers: for (int i = 0; i < 10; i++) { NSArray *factorList = (NSArray *)[factorData objectAtIndex:i]; NSLog(@"Factors of %d\n", i + 1); for (int j = 0; j < [factorList count]; j++) { NSLog(@" %d\n", (NSNumber *)[factorList objectAtIndex:j]); } } I see all the correct number of values, but the values themselves are incorrect, i.e.: Factors of 3 61879840 (should be 1) 61961200 (should be 3) Factors of 4 61879840 (should be 1) 61943472 (should be 2) 61943632 (should be 4) Factors of 5 61879840 (should be 1) 61943616 (should be 5)

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  • Defining a Class in Objective C, XCode

    - by Brett
    Hello; I am new to Objective C, and am trying to write a class that defines a complex number. The code seems fine but when I print to the console, my values for instance variables are 0. Here is the code: // // ComplexNumber.h // Mandelbrot Set // // Created by Brett on 10-06-02. // Copyright 2010 __MyCompanyName__. All rights reserved. // #import <Foundation/Foundation.h> #import <stdio.h> @interface ComplexNumber : NSObject { double real; double imaginary; } // Getters -(double) real; -(double) imaginary; // Setters -(void)setReal: (double) a andImaginary: (double) b; //Function -(ComplexNumber *)squared; @end // // ComplexNumber.m // Mandelbrot Set // // Created by Brett on 10-06-02. // Copyright 2010 __MyCompanyName__. All rights reserved. // #import "ComplexNumber.h" #import <math.h> #import <stdio.h> @implementation ComplexNumber -(double)real{ return self->real; } -(double)imaginary{ return self->imaginary; } -(void)setReal: (double) a andImaginary: (double) b{ self->real=a; self->imaginary=b; } -(ComplexNumber *)squared{ double a = pow(real,2); double b = pow(imaginary, 2); double c = 2*real*imaginary; ComplexNumber *d; [d setReal:(a-b) andImaginary: c]; return d; } @end In the App Delegate for debugging purposes I added: - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { ComplexNumber *testNumber = [[ComplexNumber alloc] init]; [testNumber setReal:55.0 andImaginary:30.0]; NSLog(@"%d", testNumber.real); // Override point for customization after app launch [window addSubview:viewController.view]; [window makeKeyAndVisible]; return YES; } But the console returns 0 everytime. Help?

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  • Lua and Objective C not running script.

    - by beta
    I am trying to create an objective c interface that encapsulates the functionality of storing and running a lua script (compiled or not.) My code for the script interface is as follows: #import <Cocoa/Cocoa.h> #import "Types.h" #import "lua.h" #include "lualib.h" #include "lauxlib.h" @interface Script : NSObject<NSCoding> { @public s32 size; s8* data; BOOL done; } @property s32 size; @property s8* data; @property BOOL done; - (id) initWithScript: (u8*)data andSize:(s32)size; - (id) initFromFile: (const char*)file; - (void) runWithState: (lua_State*)state; - (void) encodeWithCoder: (NSCoder*)coder; - (id) initWithCoder: (NSCoder*)coder; @end #import "Script.h" @implementation Script @synthesize size; @synthesize data; @synthesize done; - (id) initWithScript: (s8*)d andSize:(s32)s { self = [super init]; self->size = s; self->data = d; return self; } - (id) initFromFile:(const char *)file { FILE* p; p = fopen(file, "rb"); if(p == NULL) return [super init]; fseek(p, 0, SEEK_END); s32 fs = ftell(p); rewind(p); u8* buffer = (u8*)malloc(fs); fread(buffer, 1, fs, p); fclose(p); return [self initWithScript:buffer andSize:size]; } - (void) runWithState: (lua_State*)state { if(luaL_loadbuffer(state, [self data], [self size], "Script") != 0) { NSLog(@"Error loading lua chunk."); return; } lua_pcall(state, 0, LUA_MULTRET, 0); } - (void) encodeWithCoder: (NSCoder*)coder { [coder encodeInt: size forKey: @"Script.size"]; [coder encodeBytes:data length:size forKey:@"Script.data"]; } - (id) initWithCoder: (NSCoder*)coder { self = [super init]; NSUInteger actualSize; size = [coder decodeIntForKey: @"Script.size"]; data = [[coder decodeBytesForKey:@"Script.data" returnedLength:&actualSize] retain]; return self; } @end Here is the main method: #import "Script.h" int main(int argc, char* argv[]) { Script* script = [[Script alloc] initFromFile:"./test.lua"]; lua_State* state = luaL_newstate(); luaL_openlibs(state); luaL_dostring(state, "print(_VERSION)"); [script runWithState:state]; luaL_dostring(state, "print(_VERSION)"); lua_close(state); } And the lua script is just: print("O Hai World!") Loading the file is correct, but I think it messes up at pcall. Any Help is greatly appreciated. Heading

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  • My mental block - struggling to learn Objective C

    - by iqessar
    Hello people, this would be my first question after signing up! Anyway heres my question, I did Java at university and I was always told I am a good programmer. However I never pursued it as a career - I went into support and management instead. Im pretty much bored with my job, I have therefore started to learn Objective C so that I can develop apps for the iphone. I am currently watching several different Videos / Books. My problem is that when I go through the Apple documentation, although I understand most of it, sometimes I stumble. I believe that because you/we have the Apple documentation (i.e. Framework references) , everything should be clear, and therefore you should have no need to refer to a book or video (in order to learn how to use a particular class). But I alway do refer to a book and video and subsequently feel guilty as I believe the framework reference should be enough. (I therefore feel I am not up to being a programmer) I also believe that you shouldn't need example code in order to learn how to use a particular class because Apple provides documentation for each class, but AGAIN I find my self googling example code and I find my answer like that - again I feel guilty for doing this. Am I right in saying that Apple documentation is simply not clear? and that its ok to refer to a video/book or google? or forums for that matter? I have proffesional programmers who tell me that I am worrying too much and that I should get on with it and use all the resources that I have. I just cant seem to get round this mental block that I have in my head. When I start a programming project I am able to use the excellent search skills that I have to find the code I need, copy and paste it (yes I do understand it) BUT then I feel guilty telling myself that why didn't you think up the code yourself???? Therefore your not a real programmer, your just good at googling. Currently I am going through 20+ books so that I can learn most of the frameworks, syntax etc to develop iphone apps. I believe if I do this, then when I think of a project I can make it quickly. Should I read a few books, like 2-3 and then just start a project /app , and if I get stuck just google it and get the code I need? Can anybody please answer my questions?

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  • Objective-c design advice for use of different data sources, swapping between test and live

    - by user200341
    I'm in the process of designing an application that is part of a larger piece of work, depending on other people to build an API that the app can make use of to retrieve data. While I was thinking about how to setup this project and design the architecture around it, something occurred to me, and I'm sure many people have been in similar situations. Since my work is depending on other people to complete their tasks, and a test server, this slows work down at my end. So the question is: What's the best practice for creating test repositories and classes, implementing them, and not having to depend on altering several places in the code to swap between the test classes and the actual repositories / proper api calls. Contemplate the following scenario: GetDataFromApiCommand *getDataCommand = [[GetDataFromApiCommand alloc]init]; getDataCommand.delegate = self; [getDataCommand getData]; Once the data is available via the API, "GetDataFromApiCommand" could use the actual API, but until then a set of mock data could be returned upon the call of [getDataCommand getData] There might be multiple instances of this, in various places in the code, so replacing all of them wherever they are, is a slow and painful process which inevitably leads to one or two being overlooked. In strongly typed languages we could use dependency injection and just alter one place. In objective-c a factory pattern could be implemented, but is that the best route to go for this? GetDataFromApiCommand *getDataCommand = [GetDataFromApiCommandFactory buildGetDataFromApiCommand]; getDataCommand.delegate = self; [getDataCommand getData]; What is the best practices to achieve this result? Since this would be most useful, even if you have the actual API available, to run tests, or work off-line, the ApiCommands would not necessarily have to be replaced permanently, but the option to select "Do I want to use TestApiCommand or ApiCommand". It is more interesting to have the option to switch between: All commands are test and All command use the live API, rather than selecting them one by one, however that would also be useful to do for testing one or two actual API commands, mixing them with test data. EDIT The way I have chosen to go with this is to use the factory pattern. I set up the factory as follows: @implementation ApiCommandFactory + (ApiCommand *)newApiCommand { // return [[ApiCommand alloc]init]; return [[ApiCommandMock alloc]init]; } @end And anywhere I want to use the ApiCommand class: GetDataFromApiCommand *getDataCommand = [ApiCommandFactory newApiCommand]; When the actual API call is required, the comments can be removed and the mock can be commented out. Using new in the message name implies that who ever uses the factory to get an object, is responsible for releasing it (since we want to avoid autorelease on the iPhone). If additional parameters are required, the factory needs to take these into consideration i.e: [ApiCommandFactory newSecondApiCommand:@"param1"]; This will work quite well with repositories as well.

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  • Calculating negative fractions in Objective C

    - by Mark Reid
    I've been coding my way through Steve Kochan's Programming in Objective-C 2.0 book. I'm up to an exercise in chapter 7, ex 4, in case anyone has the book. The question posed by the exercise it will the Fraction class written work with negative fractions such as -1/2 + -2/3? Here's the implementation code in question - @implementation Fraction @synthesize numerator, denominator; -(void) print { NSLog(@"%i/%i", numerator, denominator); } -(void) setTo: (int) n over: (int) d { numerator = n; denominator = d; } -(double) convertToNum { if (denominator != 0) return (double) numerator / denominator; else return 1.0; } -(Fraction *) add: (Fraction *) f { // To add two fractions: // a/b + c/d = ((a * d) + (b * c)) / (b * d) // result will store the result of the addition Fraction *result = [[Fraction alloc] init]; int resultNum, resultDenom; resultNum = (numerator * f.denominator) + (denominator * f.numerator); resultDenom = denominator * f.denominator; [result setTo: resultNum over: resultDenom]; [result reduce]; return result; } -(Fraction *) subtract: (Fraction *) f { // To subtract two fractions: // a/b - c/d = ((a * d) - (b * c)) / (b * d) // result will store the result of the addition Fraction *result = [[Fraction alloc] init]; int resultNum, resultDenom; resultNum = numerator * f.denominator - denominator * f.numerator; resultDenom = denominator * f.denominator; [result setTo: resultNum over: resultDenom]; [result reduce]; return result; } -(Fraction *) multiply: (Fraction *) f { // To multiply two fractions // a/b * c/d = (a*c) / (b*d) // result will store the result of the addition Fraction *result = [[Fraction alloc] init]; int resultNum, resultDenom; resultNum = numerator * f.numerator; resultDenom = denominator * f.denominator; [result setTo: resultNum over: resultDenom]; [result reduce]; return result; } -(Fraction *) divide: (Fraction *) f { // To divide two fractions // a/b / c/d = (a*d) / (b*c) // result will store the result of the addition Fraction *result = [[Fraction alloc] init]; int resultNum, resultDenom; resultNum = numerator * f.denominator; resultDenom = denominator * f.numerator; [result setTo: resultNum over: resultDenom]; [result reduce]; return result; } -(void) reduce { int u = numerator; int v = denominator; int temp; while (v != 0) { temp = u % v; u = v; v = temp; } numerator /= u; denominator /= u; } @end My question to you is will it work with negative fractions and can you explain how you know? Part of the issue is I don't know how to calculate negative fractions myself so I'm not too sure how to know. Many thanks.

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  • Objective-C vs JavaScript loop performance

    - by micadelli
    I have a PhoneGap mobile application that I need to generate an array of match combinations. In JavaScript side, the code hanged pretty soon when the array of which the combinations are generated from got a bit bigger. So, I thought I'll make a plugin to generate the combinations, passing the array of javascript objects to native side and loop it there. To my surprise the following codes executes in 150 ms (JavaScript) whereas in native side (Objective-C) it takes ~1000 ms. Does anyone know any tips for speeding up those executing times? When players exceeds 10, i.e. the length of the array of teams equals 252 it really gets slow. Those execution times mentioned above are for 10 players / 252 teams. Here's the JavaScript code: for (i = 0; i < GAME.teams.length; i += 1) { for (j = i + 1; j < GAME.teams.length; j += 1) { t1 = GAME.teams[i]; t2 = GAME.teams[j]; if ((t1.mask & t2.mask) === 0) { GAME.matches.push({ Team1: t1, Team2: t2 }); } } } ... and here's the native code: NSArray *teams = [[NSArray alloc] initWithArray: [options objectForKey:@"teams"]]; NSMutableArray *t = [[NSMutableArray alloc] init]; int mask_t1; int mask_t2; for (NSInteger i = 0; i < [teams count]; i++) { for (NSInteger j = i + 1; j < [teams count]; j++) { mask_t1 = [[[teams objectAtIndex:i] objectForKey:@"mask"] intValue]; mask_t2 = [[[teams objectAtIndex:j] objectForKey:@"mask"] intValue]; if ((mask_t1 & mask_t2) == 0) { [t insertObject:[teams objectAtIndex:i] atIndex:0]; [t insertObject:[teams objectAtIndex:j] atIndex:1]; /* NSArray *newCombination = [[NSArray alloc] initWithObjects: [teams objectAtIndex:i], [teams objectAtIndex:j], nil]; */ [combinations addObject:t]; } } } ... the array in question (GAME.teams) looks like this: { count = 2; full = 1; list = ( { index = 0; mask = 1; name = A; score = 0; }, { index = 1; mask = 2; name = B; score = 0; } ); mask = 3; name = A; }, { count = 2; full = 1; list = ( { index = 0; mask = 1; name = A; score = 0; }, { index = 2; mask = 4; name = C; score = 0; } ); mask = 5; name = A; },

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  • changing output in objective-c app

    - by Zack
    // // RC4.m // Play5 // // Created by svp on 24.05.10. // Copyright 2010 __MyCompanyName__. All rights reserved. // #import "RC4.h" @implementation RC4 @synthesize txtLyrics; @synthesize sbox; @synthesize mykey; - (IBAction) clicked: (id) sender { NSData *asciidata1 = [@"4875" dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES]; NSString *asciistr1 = [[NSString alloc] initWithData:asciidata1 encoding:NSASCIIStringEncoding]; //[txtLyrics setText:@"go"]; NSData *asciidata = [@"sdf883jsdf22" dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES]; NSString *asciistr = [[NSString alloc] initWithData:asciidata encoding:NSASCIIStringEncoding]; //RC4 * x = [RC4 alloc]; [txtLyrics setText:[self decrypt:asciistr1 andKey:asciistr]]; } - (NSMutableArray*) hexToChars: (NSString*) hex { NSMutableArray * arr = [[NSMutableArray alloc] init]; NSRange range; range.length = 2; for (int i = 0; i < [hex length]; i = i + 2) { range.location = 0; NSString * str = [[hex substringWithRange:range] uppercaseString]; unsigned int value; [[NSScanner scannerWithString:str] scanHexInt:&value]; [arr addObject:[[NSNumber alloc] initWithInt:(int)value]]; } return arr; } - (NSString*) charsToStr: (NSMutableArray*) chars { NSString * str = @""; for (int i = 0; i < [chars count]; i++) { str = [NSString stringWithFormat:@"%@%@",[NSString stringWithFormat:@"%c", [chars objectAtIndex:i]],str]; } return str; } //perfect except memory leaks - (NSMutableArray*) strToChars: (NSString*) str { NSData *asciidata = [str dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES]; NSString *asciistr = [[NSString alloc] initWithData:asciidata encoding:NSASCIIStringEncoding]; NSMutableArray * arr = [[NSMutableArray alloc] init]; for (int i = 0; i < [str length]; i++) { [arr addObject:[[NSNumber alloc] initWithInt:(int)[asciistr characterAtIndex:i]]]; } return arr; } - (void) initialize: (NSMutableArray*) pwd { sbox = [[NSMutableArray alloc] init]; mykey = [[NSMutableArray alloc] init]; int a = 0; int b; int c = [pwd count]; int d = 0; while (d < 256) { [mykey addObject:[pwd objectAtIndex:(d % c)]]; [sbox addObject:[[NSNumber alloc] initWithInt:d]]; d++; } d = 0; while (d < 256) { a = (a + [[sbox objectAtIndex:d] intValue] + [[mykey objectAtIndex:d] intValue]) % 256; b = [[sbox objectAtIndex:d] intValue]; [sbox replaceObjectAtIndex:d withObject:[sbox objectAtIndex:a]]; [sbox replaceObjectAtIndex:a withObject:[[NSNumber alloc] initWithInt:b]]; d++; } } - (NSMutableArray*) calculate: (NSMutableArray*) plaintxt andPsw: (NSMutableArray*) psw { [self initialize:psw]; int a = 0; int b = 0; NSMutableArray * c = [[NSMutableArray alloc] init]; int d; int e; int f; int g = 0; while (g < [plaintxt count]) { a = (a + 1) % 256; b = (b + [[sbox objectAtIndex:a] intValue]) % 256; e = [[sbox objectAtIndex:a] intValue]; [sbox replaceObjectAtIndex:a withObject:[sbox objectAtIndex:b]]; [sbox replaceObjectAtIndex:b withObject:[[NSNumber alloc] initWithInt:e]]; int h = ([[sbox objectAtIndex:a]intValue] + [[sbox objectAtIndex:b]intValue]) % 256; d = [[sbox objectAtIndex:h] intValue]; f = [[plaintxt objectAtIndex:g] intValue] ^ d; [c addObject:[[NSNumber alloc] initWithInt:f]]; g++; } return c; } - (NSString*) decrypt: (NSString*) src andKey: (NSString*) key { NSMutableArray * plaintxt = [self hexToChars:src]; NSMutableArray * psw = [self strToChars:key]; NSMutableArray * chars = [self calculate:plaintxt andPsw:psw]; NSData *asciidata = [[self charsToStr:chars] dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES]; NSString *asciistr = [[NSString alloc] initWithData:asciidata encoding:NSUTF8StringEncoding]; return asciistr; } @end This is supposed to decrypt a hex string with an ascii string, using rc4 decryption. I'm converting my java application to objective-c. The output keeps changing, every time i run it.

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  • Objective-C function dispatch collisions; Or, how to achieve "namespaces"?

    - by fbrereto
    I have an application for Mac OS X that supports plugins that are intended to be loaded at the same time. Some of these plugins are built on top of a Cocoa framework that may receive updates in one plugin but not another. Given Objective-C's current method for function dispatching, any call from any plugin to a given Objective-C routine will go to the same routine every time. That means plugin A can find itself inside plugin B with a trivial Objective-C call! Obviously what we're looking for is for each plugin to interact with its own version of the framework upon which it was built. I have been reading some on Objective-C and this particular need, but haven't found a definitive solution for it yet. Update: My use of the word "framework" above is misleading: the framework is a statically-linked library, built into the plugin(s) that need it. The way Objective-C handles dispatching, however, even these statically linked pieces of disparate code will co-mingle in the Objective-C dispatcher, leading to unintended consequences. Update 2: I'm still a bit fuzzy on the answer provided here, as it doesn't seem to propose a solution as much as an unproven hypothesis.

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  • Using SQL Developer to Debug your Anonymous PL/SQL Blocks

    - by JeffS
    Everyone knows that SQL Developer has a PL/SQL debugger – check! Everyone also knows that it’s only setup for debugging standalone PL/SQL objects like Functions, Procedures, and Packages, right? – NO! SQL Developer can also debug your Stored Java Procedures AND it can debug your standalone PLSQL blocks. These bits of PLSQL which do not live in the database are also known as ‘Anonymous Blocks.’ Anonymous PL/SQL blocks can be submitted to interactive tools such as SQL*Plus and Enterprise Manager, or embedded in an Oracle Precompiler or OCI program. At run time, the program sends these blocks to the Oracle database, where they are compiled and executed. Here’s an example of something you might want help debugging: Declare x number := 0; Begin Dbms_Output.Put(Sysdate || ' ' || Systimestamp); For Stuff In 1..100 Loop Dbms_Output.Put_Line('Stuff is equal to ' || Stuff || '.'); x := Stuff; End Loop; End; / With the power of remote debugging and unshared worksheets, we are going to be able to debug this ANON block! The trick – we need to create a dummy stored procedure and call it in our ANON block. Then we’re going to create an unshared worksheet and execute the script from there while the SQL Developer session is listening for remote debug connections. We step through the dummy procedure, and this takes OUT to our calling ANON block. Then we can use watches, breakpoints, and all that fancy debugger stuff! First things first, create this dummy procedure - create or replace procedure do_nothing is begin null; end; Then mouse-right-click on your Connection and select ‘Remote Debug.’ For an in-depth post on how to use the remote debugger, check out Barry’s excellent post on the subject. Open an unshared worksheet using Ctrl+Shift+N. This gives us a dedicated connection for our worksheet and any scripts or commands executed in it. Paste in your ANON block you want to debug. Add in a call to the dummy procedure above to the first line of your BEGIN block like so Begin do_nothing(); ... Then we need to setup the machine for remote debug for the session we have listening – basically we connect to SQL Developer. You can do that via a Environment Variable, or you can just add this line to your script - CALL DBMS_DEBUG_JDWP.CONNECT_TCP( 'localhost', '4000' ); Where ‘localhost’ is the machine where SQL Developer is running and ’4000′ is the port you started the debug listener on. Ok, with that all set, now just RUN the script. Once the PL/SQL call is made, the debugger will be invoked. You’ll end up in the DO_NOTHING() object. Debugging an ANON block from SQL Developer is possible! If you step out to the ANON block, we’ll end up in the script that’s used to call the procedure – which is the script you want to debug. The Anonymous Block is opened in a new SQL Dev page You can now step through the block, using watches and breakpoints as expected. I’m guessing your scripts are going to be a bit more complicated than mine, but this serves as a decent example to get you started. Here’s a screenshot of a watch and breakpoint defined in the anon block being debugged: Breakpoints, watches, and callstacks - oh my! For giggles, I created a breakpoint with a passcount of 90 for the FOR LOOP to see if it works. And of course it does You Might Also EnjoyUsing Pass Counts to Turbo Charge Your PL/SQL BreakpointsSQL Developer Tip: Viewing REFCURSOR OutputThe PL/SQL Debugger Strikes Back: Episode VDebugging PL/SQL with SQL Developer: Episode IVHow to find dependent objects in your PL/SQL Programs using SQL Developer

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