Retain/release question

FROM : Bruce Truax
DATE : Fri Dec 10 17:05:18 2004

I am still struggling with the retain/release concept. I hope someday to
fully understand it.  Most of the time I end up with the correct pairing
because I poke around and look at the retain count and because most times it
does not make much difference.  I now have a case where I want to create a 2
dimensional NSArray from a C array of floats and I have upwards of 200,000
elements in the array so I don't want to have a lot of improperly retained
variables.  Below I have included the source code to the function which
creates the array.  Could someone provide me with the proper retain/release
protocol?  Should I set up an autorelease pool for this function?

When I call the function I the calling statement is:

    [self setDisplayArray:[self buildArrayFromCArray:outputArray
                                              ofSize:numberOfPoints
                                      withXDimension:xSize
                                    withYDimensiont:ySize]];


When I call this setter function and the display array is released I want to
make sure that all of the row arrays are also released.

- (NSMutableArray *)buildArrayFromCArray:(float*)input
                      ofSize:(int)nPoints
              withXDimension:(int)xDimension
            withYDimensiont:(int) yDimension
{
    NSMutableArray *theArray;
    int column=0;
    int row=0;
    int i=0;
   
    theArray = [[NSMutableArray alloc] initWithCapacity:xDimension];
    for (column = 0; column<xDimension; column++){
        NSMutableArray *rowArray = [[NSMutableArray
alloc]initWithCapacity:yDimension];
        for (row = 0;row<yDimension; row++){
            NSNumber *point = [[NSNumber alloc] initWithFloat:input[i]];
            [rowArray addObject:point];
            i++;
        }
        [theArray addObject:rowArray];
    }
    return theArray;
}

Thanks.

Bruce