iphone - NSArray of int[]

Question

I am needing to store a heap of int[] for my levels.

I decided that storing the int[]'s in an NSMutableArray and getting a random one from the array would be a good way to do it.

Thing is, an int[] is not an object and you cannot add it inside an obj-c array.

Does anyone have a suggestion on how I can get a random integer array?

My arrays looks like this:

int lvl1[] { 4,80,49,6,40,77,21,20,91,5,100,91,...... }; 
int lvl2[] { 20,260,385,20,290,448,21,210,329,21,...... }; 
int lvl3[] { 441,21,90,364,21,70,385,21,170,434,...... }; 
...
int lvl50[] { 441,21,90,364,21,70,385,21,170,434,...... }; 

I then need to get a random one of these.

Answer 1

EDIT: changed to use a less evil method courtesy of Tommy's comment.

You can treat the static arrays as pointers and store them in NSValue objects:

[mutableArray addObject:[NSValue valueWithPointer:lvl1]];

...

int* level = [(NSValue*)[mutableArray objectAtIndex:whatever] pointerValue];
int someContainedInt = level[index];

Alternatively, you could wrap each individual array in its own NSData object and store those in the mutable array:

[mutableArray addObject:[NSData dataWithBytes:lvl1 length:sizeof(int) * lengthOfArray]];

...

const int* level = (const int*) [(NSData*) [mutableArray objectAtIndex:whatever] bytes];

I have to concur with Frank C, though -- why do you need to use a Cocoa array to store these arrays at all? Can't you just treat the whole lot as a 2D C array? If it's static data anyway then the dynamic aspects of NSMutableArray seem pretty much superfluous.

EDIT 2: Using C arrays

If your level arrays are all the same length -- call it LEVEL_SIZE -- you can build a straight 2D array like this:

static int levels[][LEVEL_SIZE] = 
{
    {1, 2, 3, 4, ...},
    {15, 17, 19, 21, ...},
    {8, 7, 6, 5, ...}
};

Otherwise, you'll need to build each array separately and then put them together afterwards:

static int level1[] = {1, 2, 3, 4, ...};
static int level2[] = {15, 17, 19, 21, ...};
static int level3[] = {8, 7, 6, 5, ...};
...
static int* levels[] = {lvl1, lvl2, lvl3, ...};

Either way, you can pluck out one level as a pointer:

int* level = levels[0];
printf("%d
", level[1]); // should print 2

To start with, you'll have NUM_LEVELS levels -- in your case 50 -- so stick that many indices 0..49 into your mutable array, as NSNumber objects:

NSMutableArray* levelIndices = [NSMutableArray arrayWithCapacity:NUM_LEVELS];
for ( int i = 0; i < NUM_LEVELS; ++i )
    [levelIndices addObject:[NSNumber numberWithInt:i]];

Use this array for your counting, getting and removing needs. When you pull an NSNumber object out, use it to index into the levels array to get the level:

int* level = levels[[someNSNumber intValue]];

Et voila.