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

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: @" "];
    }
}