How can a string be converted into binary with the spaces intact? - objective-c

Question

For my app, I want to convert an NSString to a NSMutableString containing the binary equivalent. All spaces must be put in the appropriate spot.
I've found a snippet that converts the string to binary, but all spaces are excluded. It looked like this more or less:
NSMutableString *str2 = [NSMutableString stringWithFormat:#""];
for(NSInteger numberCopy = str; numberCopy > 0; numberCopy >>=1) {
//Prepend "0" or "1", depending on the bit
[str2 insertString:((numberCopy & 1) ? #"1" : #"0") atIndex:0];
}
Str is input, str2 is output.
For the version that includes spaces, I have an array divide the input string by componentsSeparatedByString: #" ", and then the binary converter snippet (above) to each array object. I add the spaces back in.
However, I get the console error
*** -[__NSArrayM objectAtIndex:]: index 2 beyond bounds [0 .. 1]
Followed by this (although I don't think its important):
0 CoreFoundation 0x00007fff84a08b06 __exceptionPreprocess + 198
1 libobjc.A.dylib 0x00007fff8c72f3f0 objc_exception_throw + 43
2 CoreFoundation 0x00007fff849a58ec -[__NSArrayM objectAtIndex:] + 252
3 G-Clock 0x0000000100001ff1 -[GCAppController tick:] + 1937
4 Foundation 0x00007fff8a011d05 __NSFireDelayedPerform + 358
5 CoreFoundation 0x00007fff849c5804 __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 20
6 CoreFoundation 0x00007fff849c531d __CFRunLoopDoTimer + 557
7 CoreFoundation 0x00007fff849aaad9 __CFRunLoopRun + 1529
8 CoreFoundation 0x00007fff849aa0e2 CFRunLoopRunSpecific + 290
9 HIToolbox 0x00007fff83bbdeb4 RunCurrentEventLoopInMode + 209
10 HIToolbox 0x00007fff83bbdb94 ReceiveNextEventCommon + 166
11 HIToolbox 0x00007fff83bbdae3 BlockUntilNextEventMatchingListInMode + 62
12 AppKit 0x00007fff88b7a533 _DPSNextEvent + 685
13 AppKit 0x00007fff88b79df2 -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 128
14 AppKit 0x00007fff88b711a3 -[NSApplication run] + 517
15 AppKit 0x00007fff88b15bd6 NSApplicationMain + 869
16 G-Clock 0x0000000100000ea2 main + 34
17 libdyld.dylib 0x00007fff864fc7e1 start + 0
18 ??? 0x0000000000000003 0x0 + 3
)
I can't figure out whats wrong, let alone how to change it.
My code, with str being input and str2 being output:
//Convert to binary
NSMutableString *str2 = [NSMutableString stringWithFormat:#""];
int count = -1;
NSArray *array = [str componentsSeparatedByString: #" "];
NSUInteger numObjects = [array count];
//Converts each object of array into binary separately, so spaces remain intact.
while (1) {
++count;
NSString *string = array[count];
NSMutableString *mutStr = [NSMutableString stringWithFormat:#""];
for (NSInteger numberCopy = [string intValue]; numberCopy > 0; numberCopy >>=1) {
//Prepend "0" or "1", depending on the bit
[mutStr insertString:((numberCopy & 1) ? #"1" : #"0") atIndex:0];
}
if (numObjects != count + 1) {
//Add space if this is not last run through
[mutStr appendString: #" "];
} else break;
[str2 appendString: mutStr];
}

Answer 1

You have two places in the loop where count is incremented.
Also mutStr must be appended to str2 in any case.
But I would use a for-loop instead:
for (count = 0; count < numObjects; count++) {
NSString *string = array[count];
NSMutableString *mutStr = [NSMutableString stringWithFormat:#""];
for (NSInteger numberCopy = [string intValue]; numberCopy > 0; numberCopy >>=1) {
//Prepend "0" or "1", depending on the bit
[mutStr insertString:((numberCopy & 1) ? #"1" : #"0") atIndex:0];
}
[str2 appendString: mutStr];
if (numObjects != count + 1) {
//Add space if this is not last run through
[str2 appendString: #" "];
}
}

Answer 2

It was a logic error. After #Martin 's part, on the last run, the else break was after the part where [array count] was called, and since there was no array object at that index of count, the program broke.
while (1) {
++count;
if (count == numbObjects)
break;
...
}