private unsafe Page AllocateMoreSpace(FixedSizeTree fst)
{
int numberOfPagesToAllocate = GetNumberOfPagesToAllocate();
var allocatePage = _llt.AllocatePage(numberOfPagesToAllocate);
_llt.BreakLargeAllocationToSeparatePages(allocatePage.PageNumber);
var initialPageNumber = allocatePage.PageNumber;
bool isNew;
byte *ptr;
using (fst.DirectAdd(initialPageNumber, out isNew, out ptr))
{
if (isNew == false)
{
ThrowInvalidExistingBuffer();
}
// in 32 bits, we pre-allocate just 256 KB, not 2MB
Debug.Assert(numberOfPagesToAllocate % 8 == 0);
Debug.Assert(numberOfPagesToAllocate % 8 <= BitmapSize);
Memory.Set(ptr, 0xFF, BitmapSize); // mark the pages that we haven't allocated as busy
Memory.Set(ptr, 0, numberOfPagesToAllocate / 8); // mark just the first part as free
}
return(allocatePage);
}
private unsafe void UnsetValue(FixedSizeTree fst, long pageNumber, int positionInBitmap)
{
bool isNew;
byte *ptr;
using (fst.DirectAdd(pageNumber, out isNew, out ptr))
{
if (isNew)
{
ThrowInvalidNewBuffer();
}
PtrBitVector.SetBitInPointer(ptr, positionInBitmap, false);
// ptr[positionInBitmap / 8] &= (byte) ~(1 << (positionInBitmap % 8));
}
}
private unsafe Page AllocateMoreSpace(FixedSizeTree fst)
{
var allocatePage = _llt.AllocatePage(NumberOfPagesInSection);
_llt.BreakLargeAllocationToSeparatePages(allocatePage.PageNumber);
var initialPageNumber = allocatePage.PageNumber;
bool isNew;
byte *ptr;
using (fst.DirectAdd(initialPageNumber, out isNew, out ptr))
{
if (isNew == false)
{
ThrowInvalidExistingBuffer();
}
Memory.Set(ptr, 0, BitmapSize); // mark all pages as free
}
return(allocatePage);
}
