/// <summary>
/// Allocates and returns the initial node page.
/// </summary>
public void Init(int initialPageSize)
{
// 0th slot: Index 0 is reserved to mean "null node". Only use 0th slot to store PageInfo.
_pageSize = initialPageSize;
_page = new XPathNode[_pageSize];
_pageInfo = new XPathNodePageInfo(null, 1);
_page[0].Create(_pageInfo);
}
/// <summary>
/// Allocate the next slot in the current node page. Return a reference to the page and the index
/// of the allocated slot.
/// </summary>
public void AllocateSlot(out XPathNode[] page, out int idx)
{
page = _page;
idx = _pageInfo.NodeCount;
// Allocate new page if necessary
if (++_pageInfo.NodeCount >= _page.Length)
{
if (_pageSize < (1 << 16))
{
// New page shouldn't contain more slots than 16 bits can address
_pageSize *= 2;
}
_page = new XPathNode[_pageSize];
_pageInfo.NextPage = _page;
_pageInfo = new XPathNodePageInfo(page, _pageInfo.PageNumber + 1);
_page[0].Create(_pageInfo);
}
}
