/// <summary>
/// Returns the pointer for the provided page index.
/// </summary>
/// <param name="pageIndex">the index of the page that has been looked up for the position.</param>
/// <param name="incrementReferencedCount">the value to increment the referenced count.</param>
/// <returns></returns>
public IntPtr GetPointerToPage(int pageIndex, int incrementReferencedCount)
{
if (m_disposed)
{
throw new ObjectDisposedException(GetType().FullName);
}
InternalPageMetaData metaData = m_listOfPages.GetValue(pageIndex);
if (incrementReferencedCount > 0)
{
long newValue = metaData.ReferencedCount + (long)incrementReferencedCount;
if (newValue > int.MaxValue)
{
metaData.ReferencedCount = int.MaxValue;
}
else if (newValue < 0)
{
metaData.ReferencedCount = 0;
}
else
{
metaData.ReferencedCount = (int)newValue;
}
m_listOfPages.OverwriteValue(pageIndex, metaData);
}
return((IntPtr)metaData.LocationOfPage);
}
/// <summary>
/// Executes a collection cycle on the pages in this list.
/// </summary>
/// <param name="shiftLevel">the number of bits to shift the referenced counter by.
/// Value may be zero but cannot be negative</param>
/// <param name="excludedList">A set of values to exclude from the collection process</param>
/// <param name="e">Arguments for the collection.</param>
/// <returns>The number of pages returned to the memory pool</returns>
/// <remarks>If the collection mode is Emergency or Critical, it will only release the required number of pages and no more</remarks>
//ToDo: Since i'll be parsing the entire list, rebuilding a new sorted tree may be quicker than removing individual blocks and copying.
//ToDo: Also, I should probably change the ShouldCollect callback to an IEnumerable<int>.
public int DoCollection(int shiftLevel, HashSet <int> excludedList, CollectionEventArgs e)
{
if (m_disposed)
{
throw new ObjectDisposedException(GetType().FullName);
}
if (shiftLevel < 0)
{
throw new ArgumentOutOfRangeException("shiftLevel", "must be non negative");
}
int collectionCount = 0;
int maxCollectCount = -1;
if (e.CollectionMode == MemoryPoolCollectionMode.Emergency || e.CollectionMode == MemoryPoolCollectionMode.Critical)
{
maxCollectCount = e.DesiredPageReleaseCount;
}
for (int x = 0; x < m_pageIndexLookupByPositionIndex.Count; x++)
{
int pageIndex = m_pageIndexLookupByPositionIndex.Values[x];
InternalPageMetaData block = m_listOfPages.GetValue(pageIndex);
block.ReferencedCount >>= shiftLevel;
m_listOfPages.OverwriteValue(pageIndex, block);
if (block.ReferencedCount == 0)
{
if (maxCollectCount != collectionCount)
{
if (!excludedList.Contains(pageIndex))
{
collectionCount++;
m_pageIndexLookupByPositionIndex.RemoveAt(x);
x--;
m_listOfPages.SetNull(pageIndex);
e.ReleasePage(block.MemoryPoolIndex);
}
}
}
}
return(collectionCount);
}