Question

I have a tight loop that iterates about 500 times. In every iteration, it will create a few NSDecimalNumber objects to do some arithmetics.

Example – this code snippet is in the for loop. the -decimalNumberByAdding: method creates a new NSDecimalNumber instance and autoreleases it.

resultDecimalNumber = [resultDecimalNumber decimalNumberByAdding:anotherDecimalNumber];

So let me get that right: If the loop is huge, I collect thousands of NSDecimalNumber objects which wait for the whole loop to finish and the method to return, in order to get autoreleased after long time waiting.

How could I prevent a memory overflow? I’ve always tried to use non-autoreleased objects, but in this case it seems I have to live with them.

Imagine this was my loop:

for(i=0, i<500, i++) {
    resultDecimalNumber = [resultDecimalNumber decimalNumberByAdding:anotherDecimalNumber];
}

What would I have to add there? Must I create a autorelease pool inside the loop and drain it? Would that make sense?

Answer 1

Yes. You should create your own autorelease pool inside the loop. This is exactly the situation that nested autorelease pools are for.