Re: Accessing buffers in NSData/NSMutableData under garbage collection

FROM : Chris Suter
DATE : Tue Feb 19 19:38:51 2008

On 19/02/2008, at 10:48 PM, Alastair Houghton wrote:

> I'm not sure what the best fix is for this.  Like Chris said, one 
> option would be to allow us to allocate "autoreleased" memory (in 
> which case -UTF8String should probably be doing that too).  Or maybe 
> the GC should support interior pointers to memory allocated with 
> NSAllocateCollectable()?


I'm not convinced that supporting interior pointers is the right 
solution. I can imagine a situation where the pointer that's lying 
around is pointing beyond the end of the array. For example, with 
optimisations this might break:

for (n = 0, myPointer = myArray; n < size; ++n, ++myPointer) {
  // Do something
}

// In the following the compiler could optimise this to be myPointer[-1]
doSomethingWith (myArray[size - 1]);
// No further references to myArray