The following error occurs on the two lines that are commented below:
Assigning to 'float' from incompatible type 'id'
NSMutableArray *redValues = [NSMutableArray array];
NSUInteger *redValuesLength = [redValues count];
NSMutableArray *arrayOne = [NSMutableArray array];
NSUInteger arrayOneLength = [arrayOne count];
__block int counter = 0;
int amount = 1;
float totalOne, diffForAverage;
NSInteger j;
totalOne = redValues[25]; // ERROR OCCURS HERE
float average = totalOne / amount;
for (j = (counter + 25); j < (redValuesLength - 25); j++)
{
diffForAverage = average - [redValues[j + 1] floatValue];
if (diffForAverage > -1 && diffForAverage < 1)
{
totalOne += [redValues[j + 1] floatValue];
amount++;
[arrayOne addObject:[NSNumber numberWithInt:(j - 25)]];
counter++;
}
else
{
if (arrayOneLength >= 15)
{
break;
counter++;
}
else
{
[arrayOne removeAllObjects];
totalOne = redValues[j + 1]; // ERROR OCCURS HERE
counter++;
}
}
}
Why is this error caused, and how can I fix it?
totalOne is float. And your array hold NSInteger. Change to that:
totalOne = [redValues[25] floatValue];
Related
In my previous question, I asked why my application was terminating early. It turns out I'm getting this warning on one of the lines below and that may help me solve my problem.
Here's the code:
NSMutableArray *redValues = [NSMutableArray array];
NSUInteger redValuesLength = [redValues count];
float totalOne, diffForAverage;
int amount = 1;
__block int counter = 0;
NSInteger j;
GPUImageVideoCamera *videoCamera = [[GPUImageVideoCamera alloc] initWithSessionPreset:AVCaptureSessionPreset640x480 cameraPosition:AVCaptureDevicePositionBack];
videoCamera.outputImageOrientation = UIInterfaceOrientationPortrait;
GPUImageAverageColor *averageColor = [[GPUImageAverageColor alloc] init];
[averageColor setColorAverageProcessingFinishedBlock:^(CGFloat redComponent, CGFloat greenComponent, CGFloat blueComponent, CGFloat alphaComponent, CMTime frameTime)
{
NSLog(#"%f", redComponent);
[redValues addObject:#(redComponent * 255)];
}];
[videoCamera addTarget:averageColor];
[videoCamera startCameraCapture];
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, 27 * NSEC_PER_SEC), dispatch_get_main_queue(), ^{
[videoCamera stopCameraCapture];
});
totalOne = [redValues[25] floatValue];
float average = totalOne / amount;
for (j = (counter + 25); j < (redValuesLength - 25); j++)
{
diffForAverage = average - [redValues[j + 1] floatValue];
if (diffForAverage > -1 && diffForAverage < 1)
{
totalOne += [redValues[j + 1] floatValue];
amount++;
[arrayOne addObject:[NSNumber numberWithInt:(j - 25)]];
counter++;
}
else
{
if (arrayOneLength >= 15)
{
break;
counter++; // WARNING OCCURS HERE
}
else
{
[arrayOne removeAllObjects];
totalOne = [redValues[j + 1] floatValue];
counter++;
}
}
}
Why would the commented line above never be run? Is it a problem with my for loop, or my if statement, or something else entirely?
Because you have a break command just before it. The break command will immediately take you out of the for loop, so the next line won't be executed.
The arrayTwelveLEngth variable isn't working as expected. When I placed a breakpoint on the amount = 1; line above, I hovered over arrayTwelve, and found that it was empty with 0 elements. Immediately after, I then hovered about arrayTwelveLength, expecting to see 0, but instead it seems that the arrayTwelveLength had a value of 1876662112. I don't know how it got that value, and I need to solve that problem. What am I doing wrong?
NSMutableArray *redValues = [NSMutableArray array];
NSMutableArray *arrayTwelve = [NSMutableArray array];
__block int counter = 0;
__block NSInteger u;
NSUInteger redValuesLength = [redValues count];
__block int arrayTwelveLength = 0;
__block float diffForAverage, fps, averageTime, bloodSpeed;
float average;
__block int amount = 1;
__block float totalTwelve, totalThirteen;
__block NSUInteger totalNumberOfFramesInSmallArrays = 0;
__block NSUInteger totalNumberOfFramesNotInSmallArrays;
for (u = (counter + 24); u < (redValuesLength - 24); u++)
{
diffForAverage = average - [redValues[u + 1] floatValue];
float test = [redValues[u] floatValue];
arrayTwelveLength = [arrayTwelve count];
if (diffForAverage > -1 && diffForAverage < 1)
{
totalTwelve += [redValues[u + 1] floatValue];
amount++;
[arrayTwelve addObject:#(test)];
counter++;
}
else
{
if (arrayTwelveLength >= 8)
{
counter++;
break;
}
else
{
[arrayTwelve removeAllObjects];
totalTwelve = [redValues[u + 1] floatValue];
counter++;
amount = 1;
}
}
}
amount = 1; // I added a breakpoint here
totalThirteen = [redValues[u + 1] floatValue];
average = totalThirteen / amount;
if (counter == redValuesLength)
{
totalNumberOfFramesNotInSmallArrays = redValuesLength - totalNumberOfFramesInSmallArrays - 25 - (redValuesLength - counter);
fps = redValuesLength / 30;
averageTime = totalNumberOfFramesNotInSmallArrays / fps;
bloodSpeed = 3 / averageTime;
[_BloodSpeedValue setText:[NSString stringWithFormat:#"%f", bloodSpeed]];
}
if (arrayTwelveLength == NULL)
{
arrayTwelveLength = 0;
}
totalNumberOfFramesInSmallArrays += arrayTwelveLength;
You have problems with unsigned/signed types and with your data set the first for loop should not even enter, because your for loop index variable u (== 24) < (redValuesLength (== 0) - 24) but, because redValuesLength being Unsigned type it wraps around and you get:
(unsigned long)0 - (unsigned long)24 = -24 modulo ULONG_MAX + 1= 18446744073709551592
Also, you are not initialising average before usage.
I am trying to make an add method that works like long addition, so I want to start the addition from the end and work my way backwards so I can get the carrys right and etc. So I am currently trying to start working backwards over the array.
For example what im trying to do.
two arrays with the character 123456789
and i want to add them starting at 9 + 9 then move to 8+8
So I'm pretty sure I'm using the right way to iterate backwards over an array, but everytime I try I get just the runtime error, index out of bounds, and I can't figure out why. Any help would be great, I just cant figure out why it keeps throwing the exception.
-(MPInteger *) add: (MPInteger *) x
{
NSMutableArray *a = self->intString;
NSMutableArray *b = x->intString;
NSMutableArray *c = [NSMutableArray arrayWithCapacity:100];
//for (int i = 0; i < [a count]; i++) {
for (NSInteger i = [a count] - 1; i > 0; i--) {
int num = 10;
NSNumber *ourNum = [NSNumber numberWithInt:num];
NSNumber *total = [NSNumber numberWithInt:[[a objectAtIndex:i] intValue] + [[b objectAtIndex:i] intValue]];
if ([total intValue] >= [ourNum intValue]) {
total = [NSNumber numberWithInt:([total intValue] - [ourNum intValue])];
[c addObject:[NSNumber numberWithInt:([total intValue])]];
} else {
[c addObject:[NSNumber numberWithInt:[[a objectAtIndex:i] intValue]+[[b objectAtIndex:i] intValue]]];
}
NSLog(#"%#", c[i]);
}
return x;
}
First, let's clean up this code.
- (MPInteger *)add:(MPInteger *)x {
NSMutableArray *a = self->intString;
NSMutableArray *b = x->intString;
NSMutableArray *c = [NSMutableArray arrayWithCapacity:100];
for (NSInteger i = [a count] - 1; i > 0; i--) {
int num = 10;
NSNumber *ourNum = #(num);
NSNumber *total = #([a[i] intValue] + [b[i] intValue]);
if ([total intValue] >= [ourNum intValue]) {
total = #([total intValue] - [ourNum intValue]);
[c addObject:#([total intValue])];
} else {
[c addObject:#([a[i] intValue] + [b[i] intValue])];
}
NSLog(#"%#", c[i]);
}
return x;
}
Next, let's remove redundant/duplicate code.
- (MPInteger *)add:(MPInteger *)x {
NSMutableArray *a = self->intString;
NSMutableArray *b = x->intString;
NSMutableArray *c = [NSMutableArray arrayWithCapacity:100];
for (NSInteger i = [a count] - 1; i > 0; i--) {
int num = 10;
NSNumber *total = #([a[i] intValue] + [b[i] intValue]);
if ([total intValue] >= num) {
total = #([total intValue] - num);
}
[c addObject:total];
NSLog(#"%#", c[i]);
}
return x;
}
Now we can clearly see all of the issues.
You're going from [a count] - 1 to 1. You should be going all the way to 0.
a and b might have different sizes, so if you only do [a count] - 1 to 0, then if for example [b count] < [a count], you'll get an index out of bounds error when you try to access b[i].
You're adding stuff to the end of c, but you should be adding it to the beginning of c since you're iterating backwards.
You don't store the carry anywhere.
You are accessing c[i], which doesn't exist.
You are starting with an empty array 'c', and you NSLog c[i] which is obviously out of bounds on the first iteration.
I am trying to sort 15 random numbers using Objective-C in the code shown below. The code is not working as planned. I took the concept from the the insertion sort C code. The 15 random numbers are generating properly but the sort is not working.
C code:
int i, j, index;
for (i = 1; i < array_size; ++i)
{
index = a[i];
for (j = i; j > 0 && a[j-1] > index; j--)
a[j] = a[j-1];
a[j] = index;
}
Objective-C code:
-(IBAction)clicked_insertsort:(id)sender
{
NSMutableArray *array = [NSMutableArray array];
for (int x = 0; x < 15; x++)
{
[array addObject: [NSNumber numberWithInt: arc4random()%200]];
}
NSLog(#"%#",array);
{
int i, j;
id index;
for (i = 1; i < 15; ++i)
{
index = [array objectAtIndex:(NSUInteger)i]; // a[i];
for (j = i; j > 0 && [array objectAtIndex:(NSUInteger)j-1] > index; j--)
[array replaceObjectAtIndex: (j) withObject: [array objectAtIndex: (j-1)]];
[array objectAtIndex:(NSUInteger)j] == index ;
}
}
NSLog(#"%#",array);
}
You are comparing pointers, which is just sorting your array by the memory addresses of your objects, not their actual value.
index = [array objectAtIndex:(NSUInteger)i]; // a[i];
[array objectAtIndex:(NSUInteger)j-1] > index
You need to get the primitive integer value of the NSNumber:
[NSNumber numberWithInt:20] != 20; // This is wrong.
[[NSNumber numberWithInt:20] intValue] == 20; // This is correct.
Here's your code, with revisions:
-(IBAction)clicked_insertsort:(id)sender
{
NSMutableArray *array = [NSMutableArray array];
for (int x = 0; x < 15; x++)
{
[array addObject: [NSNumber numberWithInt: arc4random()%200]];
}
NSLog(#"%#",array);
{
int i, j;
id index;
for (i = 1; i < 15; ++i)
{
index = [[array objectAtIndex:(NSUInteger)i] intValue]; // a[i];
for (j = i; j > 0 && [[array objectAtIndex:(NSUInteger)j-1] intValue] > index; j--)
[array replaceObjectAtIndex: (j) withObject: [array objectAtIndex: (j-1)]];
[[array objectAtIndex:(NSUInteger)j] intValue] == index ;
}
}
NSLog(#"%#",array);
}
Actually the problem is that the algorithm itself does not make much sense.
This line:
[array objectAtIndex:(NSUInteger)j] == index ;
Should be:
[array replaceObjectAtIndex:j withObject:index]; //yes again
Try this way, with modern syntax:
-(IBAction)clicked_insertsort:(id)sender
{
NSMutableArray *array = [NSMutableArray array];
for (int x = 0; x < 15; x++)
{
[array addObject: #(arc4random()%200)];
}
NSLog(#"%#",array);
NSUInteger i, j;
for (i = 1; i < 15; ++i)
{
NSNumber *current = array[i];
for (j = i; j > 0 && [array[j-1] unsignedIntegerValue] > [current unsignedIntegerValue]; j--)
array[j] = array[j-1];
array[j] = current;
}
NSLog(#"%#",array);
}
Run the code and see the result.
I am new to Objective-C, but am an experienced developer (C#), but I can't figure this out:
I have a string which is RC4 encrypted, and I need to decrypt it using Objective-C on the iPad (iOS 5.0). I have looked all over the net for a working example, but have had no luck finding an example that works end-to-end. Not only does the code below not return the decrypted string correctly, it returns something different every time it executes, which makes me thing a pointer is being released someplace.
Note: I do not know if it matters, but the string was encrypted using http://archive.plugins.jquery.com/project/RC4 and then stored as text in a Sqlite database, which I am now accessing from Objective-C (I know, the architecture sounds messy, but I can't change that at this point.)
The code I am using is (taken from RC4 encryption - CommonCrypto (Objective-C) vs PHP):
+ (NSString*)decryptData:(NSData*) dataToDecrypt
{
const void *vplainText;
size_t plainTextBufferSize;
plainTextBufferSize = [dataToDecrypt length];
vplainText = [dataToDecrypt bytes];
CCCryptorStatus ccStatus;
uint8_t *bufferPtr = NULL;
size_t bufferPtrSize = 0;
size_t movedBytes = 0;
bufferPtrSize = (plainTextBufferSize + kCCBlockSize3DES) & ~(kCCBlockSize3DES - 1);
bufferPtr = malloc( bufferPtrSize * sizeof(uint8_t));
memset((void *)bufferPtr, 0x0, bufferPtrSize);
NSString *key = #"theKeyIUsedtoEncryptInTheFirstPlace";
const void *vkey = (const void *) [key UTF8String];
size_t keyLength = [[key dataUsingEncoding:NSUTF8StringEncoding] length];
ccStatus = CCCrypt(kCCDecrypt,
kCCAlgorithmRC4,
0,
vkey,
kCCKeySizeDES,
nil,
vplainText,
plainTextBufferSize,
(void *)bufferPtr,
bufferPtrSize,
&movedBytes);
if (ccStatus == kCCSuccess) NSLog(#"SUCCESS");
/*else*/ if (ccStatus == kCCParamError) return #"PARAM ERROR";
else if (ccStatus == kCCBufferTooSmall) return #"BUFFER TOO SMALL";
else if (ccStatus == kCCMemoryFailure) return #"MEMORY FAILURE";
else if (ccStatus == kCCAlignmentError) return #"ALIGNMENT";
else if (ccStatus == kCCDecodeError) return #"DECODE ERROR";
else if (ccStatus == kCCUnimplemented) return #"UNIMPLEMENTED";
NSString *result = [[ NSString alloc ] initWithData: [NSData dataWithBytes:(const void *)bufferPtr length:(NSUInteger)movedBytes] encoding:NSASCIIStringEncoding];
NSLog(#"%#", result);
return result;
}
Use this function for encryption and decryption. (Just put in the encoded string with same key again to decode it).
-(NSString*) rc4Key:(NSString*) key str:(NSString*) str
{
int j = 0;
unichar res[str.length];
const unichar* buffer = res;
unsigned char s[256];
for (int i = 0; i < 256; i++)
{
s[i] = i;
}
for (int i = 0; i < 256; i++)
{
j = (j + s[i] + [key characterAtIndex:(i % key.length)]) % 256;
swap(s[i], s[j]);
}
int i = j = 0;
for (int y = 0; y < str.length; y++)
{
i = (i + 1) % 256;
j = (j + s[i]) % 256;
swap(s[i], s[j]);
unsigned char f = [str characterAtIndex:y] ^ s[ (s[i] + s[j]) % 256];
res[y] = f;
}
return [NSString stringWithCharacters:buffer length:str.length];
}
I see a couple of references to DES in your code (kCCKeySizeDES, kCCBlockSize3DES). That doesn't seem right -- at a minimum, kCCKeySizeDES should probably be replaced with keyLength.
If that doesn't solve it, I'd look next at possible text encoding issues. The data in SQLite might be UTF8-encoded binary data, in which case you'll probably have to "decode" it by converting from UTF8 to ISO8859-1.
RC4 implementation translated from .net:
+(NSString*)RC4:(NSString *)data key:(NSString *)key
{
id x;
int y = 0;
int i = 0;
int j = 0;
NSMutableArray *box = [[NSMutableArray alloc] initWithCapacity:256];
NSString *result = #"";
for (i = 0; i < 256; i++) {
[box addObject:[NSNumber numberWithInt:i]];
}
for (i = 0; i < 256; i++) {
j = ((int)[key characterAtIndex:(i % key.length)] + [[box objectAtIndex:i] intValue] + j) % 256;
x = [box objectAtIndex:i];
[box setObject:[box objectAtIndex:j] atIndexedSubscript:i];
[box setObject:x atIndexedSubscript:j];
}
for (i = 0; i < data.length; i++) {
y = i % 256;
j = ([[box objectAtIndex:y] intValue] + j) % 256;
x = [box objectAtIndex:y];
[box setObject:[box objectAtIndex:j] atIndexedSubscript:y];
[box setObject:x atIndexedSubscript:j];
NSString *c = [NSString stringWithFormat:#"%c", ([data characterAtIndex:i] ^ (char)[[box objectAtIndex:([[box objectAtIndex:y] intValue] + [[box objectAtIndex:j] intValue]) % 256] intValue])];
result = [result stringByAppendingString:c];
}
return result;
}