// all sizes+addresses are in longs (8 bytes, 2 words)

// longs are stored big-endian (like twoIntsToLong)

asclass ManagedIntObjects64 {

  replace Addr with long.

  replace Addr2 with Long.

  new FreeList64 freeList;

  *() {

    alloc(reservedSpaceAtBeginning()); // so 0 is usable as the null pointer

  }

  // overridable

  public abstract long size();

  public abstract int get(Addr i);

  public abstract void set(Addr i, int val);

  public void setLong(Addr i, long val) {

    set(i, firstIntFromLong(val));

    set(i+1, secondIntFromLong(val));

  }

  public long getLong(Addr i) {

    ret twoIntsToLong(get(i), get(i+1));

  }

  swappable void onMemorySizeChanged() {}

  void ensureCapacity(long size) {

    if (memorySize() < size)

      setMemorySize(roundUpToPowerOfTwo(size));

  }

  abstract void setMemorySize(long newSize);

  void growMemory() {

    setMemorySize(max(1, memorySize()*2));

  }

  // all allocated ranges are filled with zero

  long alloc(long length) {

    LongRange r;

    while ((r = freeList.findFreeSpace(length)) == null)

      growMemory();

    freeList.remove(LongRange(r.start, r.start+length));

    ret r.start;

  }

  void free(long start, long length) {

    if (length == 0) ret;

    freeList.add(LongRange(start, start+length));

    clearMemory(start, length);

  }

  abstract void clearMemory(long start, long length);

  abstract long memorySize();

  final int read(Addr i) { ret get(i); }

  final long readLong(Addr i) { ret getLong(i); }

  final void write(Addr i, int val) { set(i, val); }

  final void writeLong(Addr i, long val) { setLong(i, val); }

  // words a pointer requires

  long sizeOfPointer() { ret 2; }

  int wordSizeInBytes() { ret 4; }

  public Addr nullPtr() { ret 0; }

  // convenience pointer array handling (memory layout: length + data)

  // it's a List, so max size 31 bit

  L<Addr2> pointerArray(Addr addr) {

    if (addr == 0) null;

    int size = get(addr);

    ret new RandomAccessAbstractList<Addr2>() {

      public int size() { ret size; }

      public Addr2 get(int i) { rangeCheck(i, size); ret readLong(addr+1+i*sizeOfPointer()); }

      public Addr2 set(int i, Int val) { rangeCheck(i, size); Addr2 old = get(i); writeLong(addr+1+i*sizeOfPointer(), val); ret old; }

    };

  }

  Addr newPointerArray(int size) {

    Addr a = alloc(size*sizeOfPointer()+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);

    memCopy(a+1, a2+1, min(oldSize, newSize));

    ret a2;

  }

  abstract void memCopy(long from, long to, long length);

  long totalFree() { ret freeList.totalFree(); }

  long reservedSpaceAtBeginning() { ret 2; }

  void collectAndCompact(IManagedObject64 rootObject) {

    ManagedIntObjects64_Collector collector = new(this);

    if (rootObject != null)

      rootObject.scanForCollection(collector);

    collector.collectAndCompact();

  }

  void printStats {

    print("Managed memory size: " + toM(size()*(long) wordSizeInBytes()) + " MB, free: " + ratioToIntPercent(freeList.totalFree(), size()) + "%");

  }

  // +1, actually

  long highestUsedWord() {

    LongRange r = freeList.highestFreeRange();

    ret r != null && r.end == size() ? r.start : size();

  }

}