/// <summary>
/// Releases db item by its reference
/// </summary>
/// <param name="reference">Reference to item to release</param>
public void Free(DbItemReference reference)
{
IPage page = _pageManager.FetchPage(reference.PageIndex);
var header = PageFormatter.GetPageHeader(page);
if (header.SizeRange == SizeRange.MultiPage)
{
while (page != null)
{
_pageManager.RemovePage(page.Index);
var nextPageIndex = ((MultipageItemPageHeader)PageFormatter.GetPageHeader(page)).NextPageIndex;
page = nextPageIndex == -1
? null
: _pageManager.FetchPage(nextPageIndex);
}
}
else
{
if (PageFormatter.ReadFixedSizeItemsCount(page) == 1)
{
_pageManager.RemovePage(page.Index);
_fsm.Set(page.Index, FsmValue.Full);
}
else
{
PageFormatter.DeleteFixedSizeItem(page, reference.ItemIndex);
_pageManager.UpdatePage(page);
_fsm.Set(page.Index, EnumHelper.FsmValueFromSizeRange(header.SizeRange));
}
}
}
public void FixedSizeItemsPage()
{
int pageSize = 32768;
var dummyPageManager = new FileSystemPageManager(pageSize);
var p = new Page(dummyPageManager, 0, new byte[pageSize]);
var header = new FixedSizeItemsPageHeader();
var r = new Random();
foreach (var sizeRange in EnumHelper.FixedSizeItemsSizeRanges())
{
header.SizeRange = sizeRange;
PageFormatter.InitPage(p, header);
var item = new DbItem(new byte[DbItem.GetMaxSize(header.SizeRange)]);
r.NextBytes(item.RawData);
// fill the page with the items
short count = 0;
bool spaceRemains = true;
while (PageFormatter.HasFreeSpaceForFixedSizeItem(p))
{
Assert.IsTrue(spaceRemains);
PageFormatter.AddFixedSizeItem(p, item, out spaceRemains);
count++;
Assert.AreEqual(count, PageFormatter.ReadFixedSizeItemsCount(p));
}
Assert.IsFalse(spaceRemains);
// check if fetched objects are equal to originals
for (short j = 0; j < PageFormatter.ReadFixedSizeItemsCount(p); j++)
{
DbItem readItem = PageFormatter.ReadFixedSizeItem(p, j);
Assert.IsTrue(AreEqualByteArrays(item.RawData, readItem.RawData));
}
// delete all added items
short itemindex = 0;
while (PageFormatter.ReadFixedSizeItemsCount(p) > 0)
{
PageFormatter.DeleteFixedSizeItem(p, itemindex);
count--;
itemindex++;
Assert.AreEqual(count, PageFormatter.ReadFixedSizeItemsCount(p));
}
}
}
