/// <summary>
/// Retrieve physical address of next iterator value
/// (under epoch protection if it is from main page buffer)
/// </summary>
/// <param name="physicalAddress"></param>
/// <param name="entryLength"></param>
/// <param name="currentAddress"></param>
/// <param name="nextAddress"></param>
/// <returns></returns>
private unsafe bool GetNextInternal(out long physicalAddress, out int entryLength, out long currentAddress, out long nextAddress)
{
while (true)
{
physicalAddress = 0;
entryLength = 0;
currentAddress = NextAddress;
nextAddress = NextAddress;
// Check for boundary conditions
if (currentAddress < allocator.BeginAddress)
{
currentAddress = allocator.BeginAddress;
}
var _currentPage = currentAddress >> allocator.LogPageSizeBits;
var _currentFrame = _currentPage % frameSize;
var _currentOffset = currentAddress & allocator.PageSizeMask;
var _headAddress = allocator.HeadAddress;
if (disposed)
{
return(false);
}
if ((currentAddress >= endAddress) || (currentAddress >= fasterLog.CommittedUntilAddress))
{
return(false);
}
if (currentAddress < _headAddress)
{
if (BufferAndLoad(currentAddress, _currentPage, _currentFrame, _headAddress))
{
continue;
}
physicalAddress = frame.GetPhysicalAddress(_currentFrame, _currentOffset);
}
else
{
physicalAddress = allocator.GetPhysicalAddress(currentAddress);
}
// Get and check entry length
entryLength = fasterLog.GetLength((byte *)physicalAddress);
if (entryLength == 0)
{
// We are likely at end of page, skip to next
currentAddress = (1 + (currentAddress >> allocator.LogPageSizeBits)) << allocator.LogPageSizeBits;
Utility.MonotonicUpdate(ref NextAddress, currentAddress, out _);
if (0 != fasterLog.GetChecksum((byte *)physicalAddress))
{
epoch.Suspend();
var curPage = currentAddress >> allocator.LogPageSizeBits;
throw new FasterException("Invalid checksum found during scan, skipping page " + curPage);
}
else
{
continue;
}
}
int recordSize = headerSize + Align(entryLength);
if (entryLength < 0 || (_currentOffset + recordSize > allocator.PageSize))
{
currentAddress = (1 + (currentAddress >> allocator.LogPageSizeBits)) << allocator.LogPageSizeBits;
if (Utility.MonotonicUpdate(ref NextAddress, currentAddress, out _))
{
epoch.Suspend();
throw new FasterException("Invalid length of record found: " + entryLength + " at address " + currentAddress + ", skipping page");
}
else
{
continue;
}
}
// Verify checksum if needed
if (currentAddress < _headAddress)
{
if (!fasterLog.VerifyChecksum((byte *)physicalAddress, entryLength))
{
var curPage = currentAddress >> allocator.LogPageSizeBits;
currentAddress = (1 + (currentAddress >> allocator.LogPageSizeBits)) << allocator.LogPageSizeBits;
if (Utility.MonotonicUpdate(ref NextAddress, currentAddress, out _))
{
epoch.Suspend();
throw new FasterException("Invalid checksum found during scan, skipping page " + curPage);
}
else
{
continue;
}
}
}
if ((currentAddress & allocator.PageSizeMask) + recordSize == allocator.PageSize)
{
currentAddress = (1 + (currentAddress >> allocator.LogPageSizeBits)) << allocator.LogPageSizeBits;
}
else
{
currentAddress += recordSize;
}
if (Utility.MonotonicUpdate(ref NextAddress, currentAddress, out long oldCurrentAddress))
{
nextAddress = currentAddress;
currentAddress = oldCurrentAddress;
return(true);
}
}
}
/// <summary>
/// Retrieve physical address of next iterator value
/// (under epoch protection if it is from main page buffer)
/// </summary>
/// <param name="physicalAddress"></param>
/// <param name="entryLength"></param>
/// <param name="epochTaken"></param>
/// <returns></returns>
private unsafe bool GetNextInternal(out long physicalAddress, out int entryLength, out bool epochTaken)
{
physicalAddress = 0;
entryLength = 0;
epochTaken = false;
currentAddress = nextAddress;
while (true)
{
// Check for boundary conditions
if (currentAddress < allocator.BeginAddress)
{
Debug.WriteLine("Iterator address is less than log BeginAddress " + allocator.BeginAddress + ", adjusting iterator address");
currentAddress = allocator.BeginAddress;
}
if ((currentAddress >= endAddress) || (currentAddress >= fasterLog.CommittedUntilAddress))
{
nextAddress = currentAddress;
return(false);
}
if (frameSize == 0 && currentAddress < allocator.HeadAddress)
{
throw new Exception("Iterator address is less than log HeadAddress in memory-scan mode");
}
var currentPage = currentAddress >> allocator.LogPageSizeBits;
var offset = currentAddress & allocator.PageSizeMask;
var headAddress = allocator.HeadAddress;
if (currentAddress < headAddress)
{
BufferAndLoad(currentAddress, currentPage, currentPage % frameSize);
physicalAddress = frame.GetPhysicalAddress(currentPage % frameSize, offset);
}
else
{
epoch.Resume();
headAddress = allocator.HeadAddress;
if (currentAddress < headAddress) // rare case
{
epoch.Suspend();
continue;
}
physicalAddress = allocator.GetPhysicalAddress(currentAddress);
}
// Get and check entry length
entryLength = fasterLog.GetLength((byte *)physicalAddress);
if (entryLength == 0)
{
if (currentAddress >= headAddress)
{
epoch.Suspend();
}
nextAddress = (1 + (currentAddress >> allocator.LogPageSizeBits)) << allocator.LogPageSizeBits;
if (0 != fasterLog.GetChecksum((byte *)physicalAddress))
{
var curPage = currentAddress >> allocator.LogPageSizeBits;
throw new Exception("Invalid checksum found during scan, skipping page " + curPage);
}
else
{
// We are likely at end of page, skip to next
currentAddress = nextAddress;
continue;
}
}
int recordSize = headerSize + Align(entryLength);
if ((currentAddress & allocator.PageSizeMask) + recordSize > allocator.PageSize)
{
if (currentAddress >= headAddress)
{
epoch.Suspend();
}
nextAddress = (1 + (currentAddress >> allocator.LogPageSizeBits)) << allocator.LogPageSizeBits;
throw new Exception("Invalid length of record found: " + entryLength + ", skipping page");
}
// Verify checksum if needed
if (currentAddress < headAddress)
{
if (!fasterLog.VerifyChecksum((byte *)physicalAddress, entryLength))
{
var curPage = currentAddress >> allocator.LogPageSizeBits;
nextAddress = (1 + (currentAddress >> allocator.LogPageSizeBits)) << allocator.LogPageSizeBits;
throw new Exception("Invalid checksum found during scan, skipping page " + curPage);
}
}
if ((currentAddress & allocator.PageSizeMask) + recordSize == allocator.PageSize)
{
nextAddress = (1 + (currentAddress >> allocator.LogPageSizeBits)) << allocator.LogPageSizeBits;
}
else
{
nextAddress = currentAddress + recordSize;
}
epochTaken = currentAddress >= headAddress;
return(true);
}
}