/// <summary>
/// Constructor
/// </summary>
/// <param name="hlog"></param>
/// <param name="beginAddress"></param>
/// <param name="endAddress"></param>
/// <param name="scanBufferingMode"></param>
/// <param name="epoch"></param>
/// <param name="forceInMemory">Provided address range is known by caller to be in memory, even if less than HeadAddress</param>
public VariableLengthBlittableScanIterator(VariableLengthBlittableAllocator <Key, Value> hlog, long beginAddress, long endAddress, ScanBufferingMode scanBufferingMode, LightEpoch epoch, bool forceInMemory = false)
: base(beginAddress == 0 ? hlog.GetFirstValidLogicalAddress(0) : beginAddress, endAddress, scanBufferingMode, epoch, hlog.LogPageSizeBits)
{
this.hlog = hlog;
this.forceInMemory = forceInMemory;
if (frameSize > 0)
{
frame = new BlittableFrame(frameSize, hlog.PageSize, hlog.GetDeviceSectorSize());
}
}
/// <summary>
/// Constructor
/// </summary>
/// <param name="hlog"></param>
/// <param name="beginAddress"></param>
/// <param name="endAddress"></param>
/// <param name="scanBufferingMode"></param>
/// <param name="epoch"></param>
/// <param name="forceInMemory">Provided address range is known by caller to be in memory, even if less than HeadAddress</param>
public unsafe VariableLengthBlittableScanIterator(VariableLengthBlittableAllocator <Key, Value> hlog, long beginAddress, long endAddress, ScanBufferingMode scanBufferingMode, LightEpoch epoch, bool forceInMemory = false)
{
this.hlog = hlog;
this.forceInMemory = forceInMemory;
// If we are protected when creating the iterator, we do not need per-GetNext protection
if (!epoch.ThisInstanceProtected())
{
this.epoch = epoch;
}
if (beginAddress == 0)
{
beginAddress = hlog.GetFirstValidLogicalAddress(0);
}
this.endAddress = endAddress;
currentAddress = -1;
nextAddress = beginAddress;
if (scanBufferingMode == ScanBufferingMode.SinglePageBuffering)
{
frameSize = 1;
}
else if (scanBufferingMode == ScanBufferingMode.DoublePageBuffering)
{
frameSize = 2;
}
else if (scanBufferingMode == ScanBufferingMode.NoBuffering)
{
frameSize = 0;
return;
}
frame = new BlittableFrame(frameSize, hlog.PageSize, hlog.GetDeviceSectorSize());
loaded = new CountdownEvent[frameSize];
// Only load addresses flushed to disk
if (nextAddress < hlog.HeadAddress && !forceInMemory)
{
var frameNumber = (nextAddress >> hlog.LogPageSizeBits) % frameSize;
hlog.AsyncReadPagesFromDeviceToFrame
(nextAddress >> hlog.LogPageSizeBits,
1, endAddress, AsyncReadPagesCallback, Empty.Default,
frame, out loaded[frameNumber]);
}
}
/// <summary>
/// Constructor
/// </summary>
/// <param name="hlog"></param>
/// <param name="beginAddress"></param>
/// <param name="endAddress"></param>
/// <param name="scanBufferingMode"></param>
public unsafe VariableLengthBlittableScanIterator(VariableLengthBlittableAllocator <Key, Value> hlog, long beginAddress, long endAddress, ScanBufferingMode scanBufferingMode)
{
this.hlog = hlog;
if (beginAddress == 0)
{
beginAddress = hlog.GetFirstValidLogicalAddress(0);
}
this.beginAddress = beginAddress;
this.endAddress = endAddress;
currentAddress = -1;
nextAddress = beginAddress;
if (scanBufferingMode == ScanBufferingMode.SinglePageBuffering)
{
frameSize = 1;
}
else if (scanBufferingMode == ScanBufferingMode.DoublePageBuffering)
{
frameSize = 2;
}
else if (scanBufferingMode == ScanBufferingMode.NoBuffering)
{
frameSize = 0;
return;
}
frame = new BlittableFrame(frameSize, hlog.PageSize, hlog.GetDeviceSectorSize());
loaded = new CountdownEvent[frameSize];
// Only load addresses flushed to disk
if (nextAddress < hlog.HeadAddress)
{
var frameNumber = (nextAddress >> hlog.LogPageSizeBits) % frameSize;
hlog.AsyncReadPagesFromDeviceToFrame
(nextAddress >> hlog.LogPageSizeBits,
1, endAddress, AsyncReadPagesCallback, Empty.Default,
frame, out loaded[frameNumber]);
}
}