// all sizes+addresses are in ints (4 bytes)
sclass ManagedIntObjects_v1 {
  int[] memory = new int[0];
  MultiMap<Int, IntRange> freeList = treeMultiMap();
  
  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");
    addToFreeList(IntRange(size, newSize));
    memory = resizeIntArray(memory, newSize);
  }
  
  void addToFreeList(IntRange r) {
    freeList.add(r.length(), r);
  }
  
  void growMemory() {
    setMemorySize(memorySize()*2);
  }
  
  int alloc(int length) {
    Int freeLength;
    while ((freeLength = freeList.data.ceilingKey(length)) == null)
      growMemory();
    freeLength.get
  }
}