sclass ManagedIntObjects_v1_Collector implements IManagedObjectCollector {
  ManagedIntObjects_v1 mem;
  TreeSet<IntRange> objects = new(intRangeComparatorByStart());
  new Set<Int> pointers;
  new Map<Int> relocationMap;
  
  *(ManagedIntObjects_v1 *mem) {}
  
  // notify collector that there is an object in a location
  public void noteObject(int start, int size) {
    objects.add(intRange(start, start+size));
  }
  
  // notify collector that there is a pointer in a location
  public void notePointer(int addr) {
    if (addr != 0)
      pointers.add(addr);
  }
  
  // notify collector that there is a pointer array in a location
  public void notePointerArray(int start) {
    if (start == 0) ret;
    int n = mem.get(start);
    noteObject(start, n+1);
    for i to n:
      notePointer(start+1+i);
  }
  
  int sizeNeeded() {
    ret totalIntRangesLength_int(objects);
  }
  
  void collectAndCompact() {
    int sizeNeeded = sizeNeeded();
    if (mem.size() == sizeNeeded) ret;
    
    // reserve new memory
    int freePtr = mem.reservedSpaceAtBeginning();
    int[] newMem = new[freePtr+sizeNeeded];
    
    // copy all the objects, fill relocationMap
    for (IntRange r : objects) {
      putIfKeyNotEqualToValue(relocationMap, r.start, freePtr);
      arraycopy(mem.mem, r.start, newMem, freePtr, r.length());
      freePtr += r.length();
    }
    
    // update the pointers
    for (int pointerAddr : pointers) {
      // find enclosing object
      IntRange obj = objects.floor(IntRange(pointerAddr, pointerAddr));
      if (obj == null) continue with print("Pointer without object");
      
      int newObjAddr = lookupOrKeep(relocationMap, obj.start);
      int newPointerAddr = newObjAddr-obj.start+pointerAddr;
      
      // find target, update pointer
      int target = mem.get(pointerAddr);
      if (target == 0) continue;
      
      Int newTarget = relocationMap.get(target);
      if (newTarget != null)
        newMem[newPointerAddr] = newTarget;
    }
    
    mem.mem = newMem;
    mem.freeList.clear();
  }
  
  // call after collectAndCompact to get new location of objects
  public int getNewLocation(int addr) {
    ret lookupOrKeep(relocationMap, addr);
  }
}