| public abstract AcquirePagePointer ( long pageNumber, PagerState pagerState = null ) : byte* | ||
| pageNumber | long | |
| pagerState | PagerState | |
| return | byte* | |
public void Write(long posBy4Kbs, int numberOf4Kbs, byte *source)
{
const int pageSizeTo4KbRatio = (Constants.Storage.PageSize / (4 * Constants.Size.Kilobyte));
var pageNumber = posBy4Kbs / pageSizeTo4KbRatio;
var offsetBy4Kb = posBy4Kbs % pageSizeTo4KbRatio;
var numberOfPages = numberOf4Kbs / pageSizeTo4KbRatio;
if (numberOf4Kbs % pageSizeTo4KbRatio != 0)
{
numberOfPages++;
}
var newPagerState = _abstractPager.EnsureContinuous(pageNumber, numberOfPages);
if (newPagerState != null)
{
_pagerState.Release();
newPagerState.AddRef();
_pagerState = newPagerState;
}
var toWrite = numberOf4Kbs * 4 * Constants.Size.Kilobyte;
byte *destination = _abstractPager.AcquirePagePointer(null, pageNumber, _pagerState)
+ (offsetBy4Kb * 4 * Constants.Size.Kilobyte);
_abstractPager.UnprotectPageRange(destination, (ulong)toWrite);
Memory.Copy(destination, source, toWrite);
_abstractPager.ProtectPageRange(destination, (ulong)toWrite);
}
public static byte *AcquirePagePointerWithOverflowHandling <T>(this AbstractPager pager, T tx, long pageNumber) where T : IPagerLevelTransactionState
{
// Case 1: Page is not overflow ==> no problem, returning a pointer to existing mapping
var pageHeader = (PageHeader *)pager.AcquirePagePointer(tx, pageNumber);
if ((pageHeader->Flags & PageFlags.Overflow) != PageFlags.Overflow)
{
return((byte *)pageHeader);
}
// Case 2: Page is overflow and already mapped large enough ==> no problem, returning a pointer to existing mapping
if (pager.EnsureMapped(tx, pageNumber, GetNumberOfOverflowPages(pageHeader->OverflowSize)) == false)
{
return((byte *)pageHeader);
}
// Case 3: Page is overflow and was ensuredMapped above, view was re-mapped so we need to acquire a pointer to the new mapping.
return(pager.AcquirePagePointer(tx, pageNumber));
}
public void Write(long pageNumber, int numberOfPages, byte *source)
{
var newPagerState = _abstractPager.EnsureContinuous(pageNumber, numberOfPages);
if (newPagerState != null)
{
_pagerState.Release();
newPagerState.AddRef();
_pagerState = newPagerState;
}
var toWrite = numberOfPages * _abstractPager.PageSize;
byte *destination = _abstractPager.AcquirePagePointer(null, pageNumber, _pagerState);
_abstractPager.UnprotectPageRange(destination, (ulong)toWrite);
Memory.BulkCopy(destination, source, toWrite);
_abstractPager.ProtectPageRange(destination, (ulong)toWrite);
}
public static Page ReadPage(this AbstractPager pager, LowLevelTransaction tx, long pageNumber, PagerState pagerState = null)
{
return(new Page(pager.AcquirePagePointer(tx, pageNumber, pagerState), pager));
}
public static TreePage Read(this AbstractPager pager, LowLevelTransaction tx, long pageNumber, PagerState pagerState = null)
{
return(new TreePage(pager.AcquirePagePointer(tx, pageNumber, pagerState), pager.DebugInfo, pager.PageSize));
}
