Fast enumeration on an NSIndexSet

Can you fast enumerate a NSIndexSet? if not, what's the best way to enumerate the items in the set?

In OS X 10.6+ and iOS SDK 4.0+, you can use the -enumerateIndexesUsingBlock: message:

NSIndexSet *idxSet = ...

[idxSet enumerateIndexesUsingBlock:^(NSUInteger idx, BOOL *stop) {
  //... do something with idx
  // *stop = YES; to stop iteration early
}];

A while loop should do the trick. It increments the index after you use the previous index.

/*int (as commented, unreliable across different platforms)*/
NSUInteger currentIndex = [someIndexSet firstIndex];
while (currentIndex != NSNotFound)
{
    //use the currentIndex

    //increment
    currentIndex = [someIndexSet indexGreaterThanIndex: currentIndex];
}