// all sizes+addresses are in ints (4 bytes)
sclass ManagedIntObjects_v1 {
  int[] memory = new int[0];
  new FreeList freeList;
  
  void ensureCapacity(int size) {
    if (memorySize() < size)
      setMemorySize(roundUpToPowerOfTwo(size));
  }
  
  int memorySize() { ret memory.length; }
  
  void setMemorySize(int newSize) {
    int size = memorySize();
    if (newSize < size) unimplemented("Shrinking memory");
    freeList.add(IntRange(size, newSize));
    memory = resizeIntArray(memory, newSize);
  }
  
  void growMemory() {
    setMemorySize(memorySize()*2);
  }
  
  int alloc(int length) {
    IntRange r;
    while ((IntRange = freeList.findFreeSpace(length)) == null)
      growMemory();
    freeList.remove(IntRange(r.start+length, r.length));
    ret r.start;
  }
}