/* user defined */
DataSegment tree {
	DataSegment tree first;
	DataSegment tree second;
	int v;
};
/* replace above to below.  */
typedef int32_t DS_offset;
struct tree {
	/* system defined.  */
	struct {
		int allocated_size;
		int size;
		DS_offset parent;
	}
	/* user defined.  */
	DS_offset first;
	DS_offset second;
	void *v;
}

tree a = new tree();
newDS(type) {
	data = malloc(defaultsize);
	data->allocated_size = defaultsize;
	data->size = sizeof(type);
	data->parent = 0;
	return data;
}

a->first = othertree; // 完全にコピーされる
// 次のように扱われる
copyDS(DS a, field fld, DS othertree) {
	DS top;
	top = a;
	while (top->parent!=0) {
		top = top + top->parent;
	}

	DS newspace;
	//if (top->allocated_size < top->size + othertree->size) realloc();
	newspace = top + top->size;
	top->size += othertree->size;

	memcpy(newspace, othertree, othertree->size);
	a->fld = newspace - a;
	newspace->parent = a - newspace;
}

*(a->first);
	*(a + a->first);

//deleteはできない




#if 0

class DS_offset {
	uint32_t offset;
}
/*   */
class DataSegmentBase {
	int allocated_size;
	int size;
	DS_offset parent;
};

DataSegment tree {
	DataSegment tree first;
	DataSegment tree second;
	int v;
};
class tree : DataSegmentBase {
	DS_offset first;
	DS_offset second;
	int v;
};

DataSegmentBase::operator new() {
}
DS_offset::operator =(DataSegmentBase ) {
}
#endif

/*
 *  -------------------------------------
 *  | Sfsv|first|second|      |
 *  -------------------------------------
 *
 */
void
main() {
	DataSegment tree a = new DataSegment tree;
	a->first = null;
	a->second = null;
	a->v = "aiueo";

	DataSegment tree top = new DataSegment tree;
	a->first = a;
	//a->first = new DataSegment tree;
	
	a->first->first = new DataSegment tree;
}