/*
* Main goals:
* 1. No copies, ever. States are deposited directly to, and read directly from, one giant ring buffer.
* As a consequence, there is no multi-threading because there is nothing to thread.
* 2. Support for arbitrary and changeable state sizes. Frequency is calculated dynamically.
* 3. No delta compression. Keep it simple. If there are cores that benefit heavily from delta compression, we should
* maintain a separate rewinder alongside this one that is customized for those cores.
*/
public ZwinderBuffer(IRewindSettings settings)
{
if (settings == null)
{
throw new ArgumentException("ZwinderBuffer's settings cannot be null.");
}
long targetSize = settings.BufferSize * 1024 * 1024;
if (settings.TargetFrameLength < 1)
{
throw new ArgumentOutOfRangeException(nameof(settings.TargetFrameLength));
}
Size = 1L << (int)Math.Floor(Math.Log(targetSize, 2));
_sizeMask = Size - 1;
_backingStoreType = settings.BackingStore;
switch (settings.BackingStore)
{
case IRewindSettings.BackingStoreType.Memory:
{
var buffer = new MemoryBlock((ulong)Size);
buffer.Protect(buffer.Start, buffer.Size, MemoryBlock.Protection.RW);
_disposables.Add(buffer);
_backingStore = new MemoryViewStream(true, true, (long)buffer.Start, (long)buffer.Size);
_disposables.Add(_backingStore);
break;
}
case IRewindSettings.BackingStoreType.TempFile:
{
var filename = TempFileManager.GetTempFilename("ZwinderBuffer");
var filestream = new FileStream(filename, FileMode.Create, FileAccess.ReadWrite, FileShare.None, 4096, FileOptions.DeleteOnClose);
filestream.SetLength(Size);
_backingStore = filestream;
_disposables.Add(filestream);
break;
}
default:
throw new ArgumentException("Unsupported store type for ZwinderBuffer.");
}
if (settings.UseFixedRewindInterval)
{
_fixedRewindInterval = true;
_targetRewindInterval = settings.TargetRewindInterval;
}
else
{
_fixedRewindInterval = false;
_targetFrameLength = settings.TargetFrameLength;
}
_allowOutOfOrderStates = settings.AllowOutOfOrderStates;
_states = new StateInfo[STATEMASK + 1];
_useCompression = settings.UseCompression;
}
/*
* Main goals:
* 1. No copies, ever. States are deposited directly to, and read directly from, one giant ring buffer.
* As a consequence, there is no multi-threading because there is nothing to thread.
* 2. Support for arbitrary and changeable state sizes. Frequency is calculated dynamically.
* 3. No delta compression. Keep it simple. If there are cores that benefit heavily from delta compression, we should
* maintain a separate rewinder alongside this one that is customized for those cores.
*/
public ZwinderBuffer(IRewindSettings settings)
{
long targetSize = settings.BufferSize * 1024 * 1024;
if (settings.TargetFrameLength < 1)
{
throw new ArgumentOutOfRangeException(nameof(settings.TargetFrameLength));
}
Size = 1L << (int)Math.Floor(Math.Log(targetSize, 2));
_sizeMask = Size - 1;
_buffer = new byte[Size];
_targetFrameLength = settings.TargetFrameLength;
_states = new StateInfo[StateMask + 1];
_useCompression = settings.UseCompression;
}
/*
* Main goals:
* 1. No copies, ever. States are deposited directly to, and read directly from, one giant ring buffer.
* As a consequence, there is no multi-threading because there is nothing to thread.
* 2. Support for arbitrary and changeable state sizes. Frequency is calculated dynamically.
* 3. No delta compression. Keep it simple. If there are cores that benefit heavily from delta compression, we should
* maintain a separate rewinder alongside this one that is customized for those cores.
*/
public ZwinderBuffer(IRewindSettings settings)
{
long targetSize = settings.BufferSize * 1024 * 1024;
if (settings.TargetFrameLength < 1)
{
throw new ArgumentOutOfRangeException(nameof(settings.TargetFrameLength));
}
Size = 1L << (int)Math.Floor(Math.Log(targetSize, 2));
_sizeMask = Size - 1;
_buffer = new MemoryBlock((ulong)Size);
_buffer.Protect(_buffer.Start, _buffer.Size, MemoryBlock.Protection.RW);
_targetFrameLength = settings.TargetFrameLength;
_states = new StateInfo[STATEMASK + 1];
_useCompression = settings.UseCompression;
}
public Zwinder(IStatable stateSource, IRewindSettings settings)
{
_buffer = new ZwinderBuffer(settings);
_stateSource = stateSource;
Active = true;
}