public void Set(long pageIndex, FsmValue value)
{
if (!_isInitialized)
{
Init();
}
IPage page = GetFsmPageByTargetPageIndex(pageIndex);
if (page == null)
{
// fsm-page is missing for requested page index
long previousPageIndex = _lastFsmPage.Index;
var missingPageCount = (int)((pageIndex - (_fsmPageCount - _fsmPageIndexes.Count) * _entryPerPage) / _entryPerPage + 1);
var pages = new List <IPage>(missingPageCount);
// allocate new pages
for (int i = 0; i < missingPageCount; i++)
{
pages.Add(_pageManager.CreatePage());
}
var baseIndex = PageFormatter.GetBasePageIndex(_lastFsmPage);
// initialize them
for (int i = 0; i < missingPageCount; i++)
{
baseIndex += _entryPerPage;
InitFsmPage(pages[i],
previousPageIndex,
i == missingPageCount - 1 ? -1 : pages[i + 1].Index,
baseIndex);
previousPageIndex = pages[i].Index;
}
// and update
pages.ForEach(_pageManager.UpdatePage);
// save reference to added pages
var lastPageHeader = (FreeSpaceMapPageHeader)PageFormatter.GetPageHeader(_lastFsmPage);
lastPageHeader.NextPageIndex = pages[0].Index;
lastPageHeader.WriteToPage(_lastFsmPage);
_pageManager.UpdatePage(_lastFsmPage);
_lastFsmPage = null;
_fsmPageCount = -1;
Set(pageIndex, value);
}
else
{
PageFormatter.SetFsmValue(page, (int)pageIndex % _entryPerPage, value);
_pageManager.UpdatePage(page);
var fsmValuesToUpdate = _luckyFsmPages.Where(item => item.Value.Page.Index == page.Index).Select(item => item.Key).ToList();
foreach (var fsmValue in fsmValuesToUpdate)
{
_luckyFsmPages[fsmValue].Page = page;
}
if (!_luckyFsmPages.ContainsKey(value))
{
_luckyFsmPages[value] = new LuckyPage {
Page = page, LastGoodIndex = pageIndex
}
}
;
else
{
if (_scanned.Contains(value))
{
_scanned.Remove(value);
}
}
}
}
public long GetFreePageIndex(FsmValue value)
{
if (!_isInitialized)
{
Init();
}
// try to find in lucky pages
if (_luckyFsmPages.ContainsKey(value))
{
IPage page = _luckyFsmPages[value].Page;
var requestedFsmIndex = (int)(_luckyFsmPages[value].LastGoodIndex % _entryPerPage);
int matchingFsmIndex;
if (PageFormatter.GetFsmValue(page, requestedFsmIndex) == value)
{
matchingFsmIndex = requestedFsmIndex;
}
else
{
matchingFsmIndex = PageFormatter.GetIndexOfFirstMatchingFsmValue(page, value);
_luckyFsmPages[value].LastGoodIndex = matchingFsmIndex;
}
if (matchingFsmIndex == -1)
{
// page becomes unlucky
_luckyFsmPages.Remove(value);
}
else
{
return(PageFormatter.GetBasePageIndex(page) + matchingFsmIndex);
}
}
var currentPageIndex = _firstFsmPageIndex;
long index = 0;
if (_scanned.Contains(value))
{
return(-1);
}
while (true)
{
// sequential scan all fsm pages for specified fsm-value
var currentPage = _pageManager.FetchPage(currentPageIndex);
int matchingFsmIndex = PageFormatter.GetIndexOfFirstMatchingFsmValue(currentPage, value);
if (matchingFsmIndex == -1)
{
index += _entryPerPage;
var header = (FreeSpaceMapPageHeader)PageFormatter.GetPageHeader(currentPage);
if (header.NextPageIndex == -1)
{
_scanned.Add(value);
return(-1);
}
currentPageIndex = header.NextPageIndex;
}
else
{
// make found page lucky
_luckyFsmPages[value] = new LuckyPage {
Page = currentPage, LastGoodIndex = matchingFsmIndex + index
};
return(index + matchingFsmIndex);
}
}
}
