// all sizes+addresses are in ints (4 bytes)
sclass ManagedIntObjects_v1 {
  replace Addr with int.
  replace Addr2 with Int.
  
  int[] mem = new int[0];
  new FreeList freeList;
  
  *() {
    alloc(1); // so 0 is usable as the null pointer
  }
  
  void ensureCapacity(int size) {
    if (memorySize() < size)
      setMemorySize(roundUpToPowerOfTwo(size));
  }
  
  int memorySize() { ret mem.length; }
  
  void setMemorySize(int newSize) {
    int size = memorySize();
    if (newSize == size) ret;
    if (newSize < size) unimplemented("Shrinking memory");
    freeList.add(IntRange(size, newSize));
    mem = resizeIntArray(mem, newSize);
  }
  
  void growMemory() {
    setMemorySize(max(1, memorySize()*2));
  }
  
  // all allocated ranges are filled with zero
  int alloc(int length) {
    IntRange r;
    while ((r = freeList.findFreeSpace(length)) == null)
      growMemory();
    
    freeList.remove(IntRange(r.start, r.start+length));
    ret r.start;
  }
  
  void free(int start, int length) {
    if (length == 0) ret;
    freeList.add(IntRange(start, start+length));
    Arrays.fill(mem, start, start+length, 0);
  }
  
  int get(Addr i) { ret mem[i]; }
  int read(Addr i) { ret mem[i]; }
  void set(Addr i, int val) { mem[i] = val; }
  void write(Addr i, int val) { mem[i] = val; }
  
  // words a pointer requires
  int sizeOfPointer() { ret 1; }
  
  Addr nullPtr() { ret 0; }
  
  // convenience pointer array handling (memory layout: length + data)
  
  L<Addr2> pointerArray(Addr addr) {
    int size = get(addr);
    ret new RandomAccessAbstractList<Addr2>() {
      public int size() { ret size; }
      public Addr2 get(int i) { rangeCheck(i, size); ret read(addr+1+i); }
      public Int set(int i, Int val) { rangeCheck(i, size); Int old = get(i); write(addr+1+i, val); ret old; }
    };
  }
  
  Addr newPointerArray(int size) {
    Addr a = alloc(size+1);
    set(a, size);
    ret a;
  }
  
  void freePointerArray(Addr a) {
    if (a != 0) free(a, read(a)+1);
  }
  
  // a can be nullPtr(), then we just make a new array
  Addr resizePointerArray(Addr a, int newSize) {
    ifdef ManagedIntObjects_v1_debug
    printFunctionCall resizePointerArray(a, newSize);
    endifdef
    if (a == 0) ret newPointerArray(newSize);
    int oldSize = get(a);
    if (oldSize == newSize) ret a;
    Addr a2 = newPointerArray(newSize);
    arraycopy(mem, a+1, mem, a2+1, min(oldSize, newSize));
    ret a2;
  }
}