/// <summary>
/// Removes all elements from the sequence from its beginning to the specified position,
/// considering that data to have been fully processed.
/// </summary>
/// <param name="position">
/// The position of the first element that has not yet been processed.
/// This is typically <see cref="ReadOnlySequence{T}.End"/> after reading all elements from that instance.
/// </param>
public void AdvanceTo(SequencePosition position)
{
var firstSegment = (SequenceSegment)position.GetObject();
if (firstSegment == null)
{
// Emulate PipeReader behavior which is to just return for default(SequencePosition)
return;
}
if (ReferenceEquals(firstSegment, SequenceSegment.Empty) && this.Length == 0)
{
// We were called with our own empty buffer segment.
return;
}
int firstIndex = position.GetInteger();
// Before making any mutations, confirm that the block specified belongs to this sequence.
var current = this.first;
while (current != firstSegment && current != null)
{
current = current.Next;
}
Requires.Argument(current != null, nameof(position), "Position does not represent a valid position in this sequence.");
// Also confirm that the position is not a prior position in the block.
Requires.Argument(firstIndex >= current.Start, nameof(position), "Position must not be earlier than current position.");
// Now repeat the loop, performing the mutations.
current = this.first;
while (current != firstSegment)
{
current = this.RecycleAndGetNext(current !);
}
firstSegment.AdvanceTo(firstIndex);
this.first = firstSegment.Length == 0 ? this.RecycleAndGetNext(firstSegment) : firstSegment;
if (this.first == null)
{
this.last = null;
}
}
private static void Byte_Default()
{
ReadOnlySequence <byte> buffer = default;
foreach (BenchmarkIteration iteration in Benchmark.Iterations)
{
int localInt = 0;
using (iteration.StartMeasurement())
{
for (int i = 0; i < Benchmark.InnerIterationCount; i++)
{
SequencePosition pos = buffer.GetPosition(0);
localInt ^= pos.GetInteger();
}
}
_volatileInt = localInt;
}
}
public bool TryGet(ref SequencePosition position, out T item, bool advance = true)
{
int index = position.GetInteger();
if (index < _count)
{
item = _array[index];
if (advance)
{
position = new SequencePosition(null, index + 1);
}
return(true);
}
item = default;
position = default;
return(false);
}
public bool HasUnexaminedData(SequencePosition examined)
{
if (IsEmpty)
{
return(false);
}
var examinedObject = examined.GetObject();
var examinedInteger = examined.GetInteger();
if (ReferenceEquals(examinedObject, _lastSegment) &&
examinedInteger == _lastIndex)
{
return(false);
}
return(true);
}
public void CheckEndReachableDoesNotCrossPastEnd()
{
var bufferSegment1 = new BufferSegment <byte>(new byte[100]);
BufferSegment <byte> bufferSegment2 = bufferSegment1.Append(new byte[100]);
BufferSegment <byte> bufferSegment3 = bufferSegment2.Append(new byte[100]);
BufferSegment <byte> bufferSegment4 = bufferSegment3.Append(new byte[100]);
var buffer = new ReadOnlySequence <byte>(bufferSegment1, 0, bufferSegment4, 100);
SequencePosition c1 = buffer.GetPosition(buffer.Start, 200);
Assert.Equal(0, c1.GetInteger());
Assert.Equal(bufferSegment3, c1.GetObject());
ReadOnlySequence <byte> seq = buffer.Slice(0, c1);
Assert.Equal(200, seq.Length);
}
private static void Char_Empty()
{
ReadOnlySequence <char> buffer = ReadOnlySequence <char> .Empty;
foreach (BenchmarkIteration iteration in Benchmark.Iterations)
{
int localInt = 0;
using (iteration.StartMeasurement())
{
for (int i = 0; i < Benchmark.InnerIterationCount; i++)
{
SequencePosition p = buffer.GetPosition(0);
localInt ^= p.GetInteger();
}
}
_volatileInt = localInt;
}
}
public bool TryFindPosition(byte[] value, out SequencePosition lastPosition)
{
if (value == null || value.Length == 0)
{
throw new ArgumentNullException(nameof(value));
}
int valueLength = value.Length;
if (valueLength == 1)
{
if (this.TryFindPosition(value[valueLength - 1], out lastPosition))
{
lastPosition.Offet(1);
}
}
SequencePosition startPosition = this.buffer.Start;
while (true)
{
if (startPosition.GetInteger() >= this.buffer.End.GetInteger())
{
break;
}
if (this.TryFindPosition(value[valueLength - 1], out var endPos))
{
var tempEndPos = endPos.Offet(1);
var startPos = this.GetStartPosition(ref tempEndPos, valueLength);
var tempSequence = this.buffer.Slice(startPos, tempEndPos);
if (this.VerifySequence(ref tempSequence, value))
{
lastPosition = tempEndPos;
return(true);
}
startPosition = tempEndPos;
}
}
lastPosition = default;
return(false);
}
public ReadWriteBytes Slice(SequencePosition start, SequencePosition end)
{
var kind = Kind;
switch (kind)
{
case Type.Array:
var(array, index) = start.Get <byte[]>();
return(new ReadWriteBytes(array, index, end.GetInteger() - index));
case Type.MemoryList:
var(startList, startIndex) = start.Get <ReadOnlySequenceSegment <byte> >();
var(endList, endIndex) = end.Get <ReadOnlySequenceSegment <byte> >();
return(new ReadWriteBytes(startList, startIndex, endList, endIndex));
default:
throw new NotImplementedException();
}
}
public void ConsumeTo(SequencePosition consumed)
{
var segment = (Segment)consumed.GetObject();
var index = consumed.GetInteger();
if (segment == _endSegment && index == _endIndex)
{
// keep the last page; burn anything else
_startSegment !.RecycleBefore(segment);
_startSegment = _endSegment;
_startIndex = _endIndex = 0;
}
else
{
// discard any pages that we no longer need
_startSegment !.RecycleBefore(segment);
_startSegment = segment;
_startIndex = index;
}
}
public ReadOnlySequence <byte> Slice(SequencePosition markStart, SequencePosition markEnd)
{
if (start == null)
{
return(ReadOnlySequence <byte> .Empty);
}
var a = (_Segment)(markStart.GetObject() ?? start);
var b = (_Segment)(markEnd.GetObject() ?? start);
var pa = markStart.GetInteger();
var pb = markEnd.GetInteger();
if (a == b && pa == pb)
{
return(ReadOnlySequence <byte> .Empty);
}
return(new ReadOnlySequence <byte>(a, pa, b, pb));
}
/// <summary>
/// Removes all elements from the sequence from its beginning to the specified position,
/// considering that data to have been fully processed.
/// </summary>
/// <param name="position">
/// The position of the first element that has not yet been processed.
/// This is typically <see cref="ReadOnlySequence{T}.End"/> after reading all elements from that instance.
/// </param>
public void AdvanceTo(SequencePosition position)
{
var firstSegment = (SequenceSegment)position.GetObject();
int firstIndex = position.GetInteger();
// Before making any mutations, confirm that the block specified belongs to this sequence.
var current = this.first;
while (current != firstSegment && current != null)
{
current = current.Next;
}
Requires.Argument(current != null, nameof(position), "Position does not represent a valid position in this sequence.");
// Also confirm that the position is not a prior position in the block.
Requires.Argument(firstIndex >= current.Start, nameof(position), "Position must not be earlier than current position.");
// Now repeat the loop, performing the mutations.
current = this.first;
while (current != firstSegment)
{
var next = current.Next;
current.ResetMemory();
current = next;
}
firstSegment.AdvanceTo(firstIndex);
if (firstSegment.Length == 0)
{
firstSegment = this.RecycleAndGetNext(firstSegment);
}
this.first = firstSegment;
if (this.first == null)
{
this.last = null;
}
}
internal SequencePosition Seek(SequencePosition start, SequencePosition end, int count, bool checkEndReachable = true)
{
int startIndex = start.GetInteger();
int endIndex = end.GetInteger();
SequenceType type = GetSequenceType();
startIndex = GetIndex(startIndex);
endIndex = GetIndex(endIndex);
switch (type)
{
case SequenceType.MemoryList:
if (start.GetObject() == end.GetObject() && endIndex - startIndex >= count)
{
return(new SequencePosition(start.GetObject(), startIndex + count));
}
return(SeekMultiSegment((IMemoryList <byte>)start.GetObject(), startIndex, (IMemoryList <byte>)end.GetObject(), endIndex, count, checkEndReachable));
case SequenceType.OwnedMemory:
case SequenceType.Array:
if (start.GetObject() != end.GetObject())
{
ThrowHelper.ThrowInvalidOperationException_EndPositionNotReached();
}
if (endIndex - startIndex >= count)
{
return(new SequencePosition(start.GetObject(), startIndex + count));
}
ThrowHelper.ThrowArgumentOutOfRangeException_CountOutOfRange();
return(default);
default:
ThrowHelper.ThrowInvalidOperationException_UnexpectedSegmentType();
return(default);
}
}
private long GetLength(SequencePosition start, SequencePosition end)
{
int startIndex = start.GetInteger();
int endIndex = end.GetInteger();
SequenceType type = GetSequenceType();
startIndex = GetIndex(startIndex);
endIndex = GetIndex(endIndex);
switch (type)
{
case SequenceType.MemoryList:
return(GetLength((IMemoryList <T>)start.GetObject(), startIndex, (IMemoryList <T>)end.GetObject(), endIndex));
case SequenceType.OwnedMemory:
case SequenceType.Array:
return(endIndex - startIndex);
default:
ThrowHelper.ThrowInvalidOperationException_UnexpectedSegmentType();
return(default);
}
}
private static void Byte_Array(int bufSize, int bufOffset)
{
var buffer = new ReadOnlySequence <byte>(new byte[bufSize], bufOffset, bufSize - 2 * bufOffset);
int offset = (int)buffer.Length / 10;
SequencePosition end = buffer.GetPosition(0, buffer.End);
foreach (BenchmarkIteration iteration in Benchmark.Iterations)
{
int localInt = 0;
using (iteration.StartMeasurement())
{
for (int i = 0; i < Benchmark.InnerIterationCount; i++)
{
SequencePosition pos = buffer.Start;
while (!pos.Equals(end))
{
pos = buffer.GetPosition(offset, pos);
localInt ^= pos.GetInteger();
}
}
}
_volatileInt = localInt;
}
}
/// <summary>
/// Initializes a new instance of the <see cref="InvalidPacketHeaderException"/> class.
/// </summary>
/// <param name="header">The header which is invalid.</param>
/// <param name="bufferContent">Content of the buffer when the header was read. With this information you can e.g. find out if a previous packet was malformed.</param>
/// <param name="position">The position of the <paramref name="header"/> in the <paramref name="bufferContent"/>.</param>
public InvalidPacketHeaderException(byte[] header, ReadOnlySequence <byte> bufferContent, SequencePosition position)
{
this.Header = header.ToArray();
this.BufferContent = bufferContent.ToArray();
this.Position = position.GetInteger();
}
/// <inheritdoc />
public override void AdvanceTo(SequencePosition consumed, SequencePosition examined)
{
ThrowIfCompleted();
AdvanceTo((BufferSegment?)consumed.GetObject(), consumed.GetInteger(), (BufferSegment?)examined.GetObject(), examined.GetInteger());
}
/// <summary>
/// Indicates how much data was consumed, and how much examined, from a read operation
/// </summary>
public override void AdvanceTo(SequencePosition consumed, SequencePosition examined)
{
var cPage = (MappedPage)consumed.GetObject();
var ePage = (MappedPage)examined.GetObject();
if (cPage == null || ePage == null)
{
if (_first == null)
{
return; // that's fine - means they called Advance on an empty EOF
}
Throw.Argument("Invalid position; consumed/examined must remain inside the buffer");
}
Debug.Assert(ePage != null, "No examined page");
Debug.Assert(cPage != null, "No consumed page");
MappedPage newKeep;
var cOffset = consumed.GetInteger();
if (cOffset == cPage.Capacity)
{
newKeep = cPage.Next;
}
else
{
newKeep = cPage;
newKeep.Consumed = cOffset;
}
if (newKeep == null)
{
DebugLog($"Retaining nothing");
_last = null;
}
else
{
DebugLog($"Retaining page {newKeep}");
}
// now drop any pages we don't need
if (newKeep != _first)
{
var page = _first;
while (page != null && page != newKeep)
{
DebugLog($"Dropping page {page}");
page.Dispose();
page = page.Next;
}
_first = newKeep;
}
// check whether they looked at everything
if (_last == null)
{
_loadMore = true; // definitely
}
else
{
var eOffset = examined.GetInteger();
_loadMore = ePage == _last && eOffset == ePage.Capacity;
}
DebugLog($"After AdvanceTo, {CountAvailable(_first)} available bytes, {_remaining} remaining unloaded bytes, load more: {_loadMore}");
}
internal bool TryGetBuffer(SequencePosition start, SequencePosition end, out ReadOnlyMemory <T> data, out SequencePosition next)
{
if (start.GetObject() == null)
{
data = default;
next = default;
return(false);
}
int startIndex = start.GetInteger();
int endIndex = end.GetInteger();
SequenceType type = GetSequenceType();
startIndex = GetIndex(startIndex);
endIndex = GetIndex(endIndex);
switch (type)
{
case SequenceType.MemoryList:
var segment = (IMemoryList <T>)start.GetObject();
Memory <T> bufferSegmentMemory = segment.Memory;
int currentEndIndex = bufferSegmentMemory.Length;
if (segment == end.GetObject())
{
currentEndIndex = endIndex;
next = default;
}
else
{
IMemoryList <T> nextSegment = segment.Next;
if (nextSegment == null)
{
if (end.GetObject() != null)
{
ThrowHelper.ThrowInvalidOperationException_EndPositionNotReached();
}
next = default;
}
else
{
next = new SequencePosition(nextSegment, 0);
}
}
data = bufferSegmentMemory.Slice(startIndex, currentEndIndex - startIndex);
return(true);
case SequenceType.OwnedMemory:
var ownedMemory = (OwnedMemory <T>)start.GetObject();
if (ownedMemory != end.GetObject())
{
ThrowHelper.ThrowInvalidOperationException_EndPositionNotReached();
}
data = ownedMemory.Memory.Slice(startIndex, endIndex - startIndex);
next = default;
return(true);
case SequenceType.Array:
var array = (T[])start.GetObject();
if (array != end.GetObject())
{
ThrowHelper.ThrowInvalidOperationException_EndPositionNotReached();
}
data = new Memory <T>(array, startIndex, endIndex - startIndex);
next = default;
return(true);
default:
ThrowHelper.ThrowInvalidOperationException_UnexpectedSegmentType();
next = default;
data = default;
return(false);
}
}
public static SequencePosition Min(SequencePosition x, SequencePosition y) => x.GetInteger() < y.GetInteger() ? x : y;
public static SequencePosition Add(this SequencePosition x, int y) => new SequencePosition(x.GetObject(), x.GetInteger() + y);
/// <inheritdoc />
public override void AdvanceTo(SequencePosition consumed, SequencePosition examined)
{
ThrowIfCompleted();
if (_readHead == null || _readTail == null)
{
ThrowHelper.ThrowInvalidOperationException_NoDataRead();
}
AdvanceTo((BufferSegment)consumed.GetObject(), consumed.GetInteger(), (BufferSegment)examined.GetObject(), examined.GetInteger());
}
internal void AdvanceReader(SequencePosition consumed, SequencePosition examined)
{
BufferSegment returnStart = null;
BufferSegment returnEnd = null;
Action continuation = null;
lock (_sync)
{
var examinedEverything = false;
if (examined.GetObject() == _commitHead)
{
examinedEverything = _commitHead != null?examined.GetInteger() == _commitHeadIndex - _commitHead.Start : examined.GetInteger() == 0;
}
if (consumed.GetObject() != null)
{
if (_readHead == null)
{
ThrowHelper.ThrowInvalidOperationException_AdvanceToInvalidCursor();
return;
}
var consumedSegment = (BufferSegment)consumed.GetObject();
returnStart = _readHead;
returnEnd = consumedSegment;
// Check if we crossed _maximumSizeLow and complete backpressure
long consumedBytes = new ReadOnlySequence <byte>(returnStart, _readHeadIndex, consumedSegment, consumed.GetInteger()).Length;
long oldLength = _length;
_length -= consumedBytes;
if (oldLength >= _resumeWriterThreshold &&
_length < _resumeWriterThreshold)
{
continuation = _writerAwaitable.Complete();
}
// Check if we consumed entire last segment
// if we are going to return commit head we need to check that there is no writing operation that
// might be using tailspace
if (consumed.GetInteger() == returnEnd.Length && _writingHead != returnEnd)
{
BufferSegment nextBlock = returnEnd.NextSegment;
if (_commitHead == returnEnd)
{
_commitHead = nextBlock;
_commitHeadIndex = 0;
}
_readHead = nextBlock;
_readHeadIndex = 0;
returnEnd = nextBlock;
}
else
{
_readHead = consumedSegment;
_readHeadIndex = consumed.GetInteger();
}
}
// We reset the awaitable to not completed if we've examined everything the producer produced so far
// but only if writer is not completed yet
if (examinedEverything && !_writerCompletion.IsCompleted)
{
// Prevent deadlock where reader awaits new data and writer await backpressure
if (!_writerAwaitable.IsCompleted)
{
ThrowHelper.ThrowInvalidOperationException_BackpressureDeadlock();
}
_readerAwaitable.Reset();
}
while (returnStart != null && returnStart != returnEnd)
{
returnStart.ResetMemory();
ReturnSegmentUnsynchronized(returnStart);
returnStart = returnStart.NextSegment;
}
_readingState.End();
}
TrySchedule(_writerScheduler, continuation);
}
