/// <summary>
/// Writes a list of items to persistent storage using a "chain" format, where each
/// page stores a "pointer" to the next page containing the following range of elements.
/// </summary>
/// <param name="stream">data file to write to</param>
/// <param name="freeSpaceMgr">object that keeps track of available pages in the file</param>
/// <param name="list">list of items to write</param>
/// <param name="pages">list of pages we wrote to</param>
public void WriteList(FileStreamWrapper stream, StoragePageManager freeSpaceMgr, List <T> list, out List <int> pages)
{
// create the pages
this.CreateNewPage(list.Count, freeSpaceMgr);
for (int idx = 0; idx < list.Count; idx++)
{
var item = list[idx];
try
{
this.pageList.Peek().AddRecord(item);
this.pageHeaderList.Peek().PageEntriesCount++;
}
catch (StoragePage.InsuffcientSpaceException)
{
this.CreateNewPage(list.Count, freeSpaceMgr);
idx--;
}
}
// write the pages
int lastPageIndex = ListHdr.EOLPageIndex;
while (0 < this.pageList.Count)
{
lastPageIndex = this.WriteTopPage(stream, lastPageIndex);
}
// set the output parameter
pages = this.pageIdxList;
}
public void SPT_TestReadWriteTable()
{
int entryCount = 40;
int physicalPageDistance = 5;
string dataFile = "SPT_TestData1.tpdb";
if (File.Exists(dataFile))
{
File.Delete(dataFile);
}
List <int> freedPages = null;
StoragePageManager spaceMgr = new StoragePageManager();
StoragePageTable pageTable2 = new StoragePageTable();
StoragePageTable pageTable = new StoragePageTable();
for (int idx = 0; idx < entryCount; idx++)
{
pageTable.SetLogicalPage(idx + physicalPageDistance);
}
using (FileStreamWrapper dataFileStream = FileStreamWrapper.CreateObject(dataFile))
{
int root = pageTable.WritePageTableData(dataFileStream, spaceMgr, out freedPages);
dataFileStream.Seek(0, SeekOrigin.Begin);
pageTable2.ReadPageTableData(dataFileStream, root);
}
for (int idx = 0; idx < entryCount; idx++)
{
int physicalAddress = pageTable2.GetPhysicalPage(idx);
Assert.AreEqual(idx + physicalPageDistance, physicalAddress);
}
}
private void CreateNewPage(int count, StoragePageManager freeSpaceMgr)
{
// create a new header object
ListHdr header = new ListHdr()
{
NextPageIndex = ListHdr.EOLPageIndex,
TotalEntriesCount = count,
PageEntriesCount = 0,
PageWriteIndex = freeSpaceMgr.GetFreePage()
};
this.pageHeaderList.Push(header);
// create the page - and write a placeholder record for the header
StoragePage page = new StoragePage();
page.AddRecord(header);
this.pageList.Push(page);
}
