Firstborn/Library/PackageCache/com.unity.inputsystem@1.5.1/InputSystem/Events/InputEventBuffer.cs

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2023-03-28 13:24:16 -04:00
using System;
using System.Collections;
using System.Collections.Generic;
using Unity.Collections;
using Unity.Collections.LowLevel.Unsafe;
using UnityEngine.InputSystem.Utilities;
////TODO: batch append method
////TODO: switch to NativeArray long length (think we have it in Unity 2018.3)
////REVIEW: can we get rid of kBufferSizeUnknown and force size to always be known? (think this would have to wait until
//// the native changes have landed in 2018.3)
namespace UnityEngine.InputSystem.LowLevel
{
/// <summary>
/// A buffer of raw memory holding a sequence of <see cref="InputEvent">input events</see>.
/// </summary>
/// <remarks>
/// Note that event buffers are not thread-safe. It is not safe to write events to the buffer
/// concurrently from multiple threads. It is, however, safe to traverse the contents of an
/// existing buffer from multiple threads as long as it is not mutated at the same time.
/// </remarks>
public unsafe struct InputEventBuffer : IEnumerable<InputEventPtr>, IDisposable, ICloneable
{
public const long BufferSizeUnknown = -1;
/// <summary>
/// Total number of events in the buffer.
/// </summary>
/// <value>Number of events currently in the buffer.</value>
public int eventCount => m_EventCount;
/// <summary>
/// Size of the used portion of the buffer in bytes. Use <see cref="capacityInBytes"/> to
/// get the total allocated size.
/// </summary>
/// <value>Used size of buffer in bytes.</value>
/// <remarks>
/// If the size is not known, returns <see cref="BufferSizeUnknown"/>.
///
/// Note that the size does not usually correspond to <see cref="eventCount"/> times <c>sizeof(InputEvent)</c>.
/// as <see cref="InputEvent"/> instances are variable in size.
/// </remarks>
public long sizeInBytes => m_SizeInBytes;
/// <summary>
/// Total size of allocated memory in bytes. This value minus <see cref="sizeInBytes"/> is the
/// spare capacity of the buffer. Will never be less than <see cref="sizeInBytes"/>.
/// </summary>
/// <value>Size of allocated memory in bytes.</value>
/// <remarks>
/// A buffer's capacity determines how much event data can be written to the buffer before it has to be
/// reallocated.
/// </remarks>
public long capacityInBytes
{
get
{
if (!m_Buffer.IsCreated)
return 0;
return m_Buffer.Length;
}
}
/// <summary>
/// The raw underlying memory buffer.
/// </summary>
/// <value>Underlying buffer of unmanaged memory.</value>
public NativeArray<byte> data => m_Buffer;
/// <summary>
/// Pointer to the first event in the buffer.
/// </summary>
/// <value>Pointer to first event in buffer.</value>
public InputEventPtr bufferPtr
{
// When using ConvertExistingDataToNativeArray, the NativeArray isn't getting a "safety handle" (seems like a bug)
// and calling GetUnsafeReadOnlyPtr() will result in a NullReferenceException. Get the pointer without checks here.
get { return (InputEvent*)NativeArrayUnsafeUtility.GetUnsafeBufferPointerWithoutChecks(m_Buffer); }
}
/// <summary>
/// Construct an event buffer using the given memory block containing <see cref="InputEvent"/>s.
/// </summary>
/// <param name="eventPtr">A buffer containing <paramref name="eventCount"/> number of input events. The
/// individual events in the buffer are variable-sized (depending on the type of each event).</param>
/// <param name="eventCount">The number of events in <paramref name="eventPtr"/>. Can be zero.</param>
/// <param name="sizeInBytes">Total number of bytes of event data in the memory block pointed to by <paramref name="eventPtr"/>.
/// If -1 (default), the size of the actual event data in the buffer is considered unknown and has to be determined by walking
/// <paramref name="eventCount"/> number of events (due to the variable size of each event).</param>
/// <param name="capacityInBytes">The total size of the memory block allocated at <paramref name="eventPtr"/>. If this
/// is larger than <paramref name="sizeInBytes"/>, additional events can be appended to the buffer until the capacity
/// is exhausted. If this is -1 (default), the capacity is considered unknown and no additional events can be
/// appended to the buffer.</param>
/// <exception cref="ArgumentException"><paramref name="eventPtr"/> is <c>null</c> and <paramref name="eventCount"/> is not zero
/// -or- <paramref name="capacityInBytes"/> is less than <paramref name="sizeInBytes"/>.</exception>
public InputEventBuffer(InputEvent* eventPtr, int eventCount, int sizeInBytes = -1, int capacityInBytes = -1)
: this()
{
if (eventPtr == null && eventCount != 0)
throw new ArgumentException("eventPtr is NULL but eventCount is != 0", nameof(eventCount));
if (capacityInBytes != 0 && capacityInBytes < sizeInBytes)
throw new ArgumentException($"capacity({capacityInBytes}) cannot be smaller than size({sizeInBytes})",
nameof(capacityInBytes));
if (eventPtr != null)
{
if (capacityInBytes < 0)
capacityInBytes = sizeInBytes;
m_Buffer = NativeArrayUnsafeUtility.ConvertExistingDataToNativeArray<byte>(eventPtr,
capacityInBytes > 0 ? capacityInBytes : 0, Allocator.None);
m_SizeInBytes = sizeInBytes >= 0 ? sizeInBytes : BufferSizeUnknown;
m_EventCount = eventCount;
m_WeOwnTheBuffer = false;
}
}
/// <summary>
/// Construct an event buffer using the array containing <see cref="InputEvent"/>s.
/// </summary>
/// <param name="buffer">A native array containing <paramref name="eventCount"/> number of input events. The
/// individual events in the buffer are variable-sized (depending on the type of each event).</param>
/// <param name="eventCount">The number of events in <paramref name="buffer"/>. Can be zero.</param>
/// <param name="sizeInBytes">Total number of bytes of event data in the <paramref cref="buffer"/>.
/// If -1 (default), the size of the actual event data in <paramref name="buffer"/> is considered unknown and has to be determined by walking
/// <paramref name="eventCount"/> number of events (due to the variable size of each event).</param>
/// <param name="transferNativeArrayOwnership">If true, ownership of the <c>NativeArray</c> given by <paramref name="buffer"/> is
/// transferred to the <c>InputEventBuffer</c>. Calling <see cref="Dispose"/> will deallocate the array. Also, <see cref="AllocateEvent"/>
/// may re-allocate the array.</param>
/// <exception cref="ArgumentException"><paramref name="buffer"/> has no memory allocated but <paramref name="eventCount"/> is not zero.</exception>
/// <exception cref="ArgumentOutOfRangeException"><paramref name="sizeInBytes"/> is greater than the total length allocated for
/// <paramref name="buffer"/>.</exception>
public InputEventBuffer(NativeArray<byte> buffer, int eventCount, int sizeInBytes = -1, bool transferNativeArrayOwnership = false)
{
if (eventCount > 0 && !buffer.IsCreated)
throw new ArgumentException("buffer has no data but eventCount is > 0", nameof(eventCount));
if (sizeInBytes > buffer.Length)
throw new ArgumentOutOfRangeException(nameof(sizeInBytes));
m_Buffer = buffer;
m_WeOwnTheBuffer = transferNativeArrayOwnership;
m_SizeInBytes = sizeInBytes >= 0 ? sizeInBytes : buffer.Length;
m_EventCount = eventCount;
}
/// <summary>
/// Append a new event to the end of the buffer by copying the event from <paramref name="eventPtr"/>.
/// </summary>
/// <param name="eventPtr">Data of the event to store in the buffer. This will be copied in full as
/// per <see cref="InputEvent.sizeInBytes"/> found in the event's header.</param>
/// <param name="capacityIncrementInBytes">If the buffer needs to be reallocated to accommodate the event, number of
/// bytes to grow the buffer by.</param>
/// <param name="allocator">If the buffer needs to be reallocated to accommodate the event, the type of allocation to
/// use.</param>
/// <exception cref="ArgumentNullException"><paramref name="eventPtr"/> is <c>null</c>.</exception>
/// <remarks>
/// If the buffer's current capacity (see <see cref="capacityInBytes"/>) is smaller than <see cref="InputEvent.sizeInBytes"/>
/// of the given event, the buffer will be reallocated.
/// </remarks>
public void AppendEvent(InputEvent* eventPtr, int capacityIncrementInBytes = 2048, Allocator allocator = Allocator.Persistent)
{
if (eventPtr == null)
throw new ArgumentNullException(nameof(eventPtr));
// Allocate space.
var eventSizeInBytes = eventPtr->sizeInBytes;
var destinationPtr = AllocateEvent((int)eventSizeInBytes, capacityIncrementInBytes, allocator);
// Copy event.
UnsafeUtility.MemCpy(destinationPtr, eventPtr, eventSizeInBytes);
}
/// <summary>
/// Make space for an event of <paramref name="sizeInBytes"/> bytes and return a pointer to
/// the memory for the event.
/// </summary>
/// <param name="sizeInBytes">Number of bytes to make available for the event including the event header (see <see cref="InputEvent"/>).</param>
/// <param name="capacityIncrementInBytes">If the buffer needs to be reallocated to accommodate the event, number of
/// bytes to grow the buffer by.</param>
/// <param name="allocator">If the buffer needs to be reallocated to accommodate the event, the type of allocation to
/// use.</param>
/// <returns>A pointer to a block of memory in <see cref="bufferPtr"/>. Store the event data here.</returns>
/// <exception cref="ArgumentException"><paramref name="sizeInBytes"/> is less than the size needed for the
/// header of an <see cref="InputEvent"/>. Will automatically be aligned to a multiple of 4.</exception>
/// <remarks>
/// Only <see cref="InputEvent.sizeInBytes"/> is initialized by this method. No other fields from the event's
/// header are touched.
///
/// The event will be appended to the buffer after the last event currently in the buffer (if any).
/// </remarks>
public InputEvent* AllocateEvent(int sizeInBytes, int capacityIncrementInBytes = 2048, Allocator allocator = Allocator.Persistent)
{
if (sizeInBytes < InputEvent.kBaseEventSize)
throw new ArgumentException(
$"sizeInBytes must be >= sizeof(InputEvent) == {InputEvent.kBaseEventSize} (was {sizeInBytes})",
nameof(sizeInBytes));
var alignedSizeInBytes = sizeInBytes.AlignToMultipleOf(InputEvent.kAlignment);
// See if we need to enlarge our buffer.
var necessaryCapacity = m_SizeInBytes + alignedSizeInBytes;
var currentCapacity = capacityInBytes;
if (currentCapacity < necessaryCapacity)
{
// Yes, so reallocate.
var newCapacity = necessaryCapacity.AlignToMultipleOf(capacityIncrementInBytes);
if (newCapacity > int.MaxValue)
throw new NotImplementedException("NativeArray long support");
var newBuffer =
new NativeArray<byte>((int)newCapacity, allocator, NativeArrayOptions.ClearMemory);
if (m_Buffer.IsCreated)
{
UnsafeUtility.MemCpy(newBuffer.GetUnsafePtr(),
NativeArrayUnsafeUtility.GetUnsafeBufferPointerWithoutChecks(m_Buffer),
this.sizeInBytes);
if (m_WeOwnTheBuffer)
m_Buffer.Dispose();
}
m_Buffer = newBuffer;
m_WeOwnTheBuffer = true;
}
var eventPtr = (InputEvent*)((byte*)NativeArrayUnsafeUtility.GetUnsafeBufferPointerWithoutChecks(m_Buffer) + m_SizeInBytes);
eventPtr->sizeInBytes = (uint)sizeInBytes;
m_SizeInBytes += alignedSizeInBytes;
++m_EventCount;
return eventPtr;
}
/// <summary>
/// Whether the given event pointer refers to data within the event buffer.
/// </summary>
/// <param name="eventPtr"></param>
/// <returns></returns>
/// <remarks>
/// Note that this method does NOT check whether the given pointer points to an actual
/// event in the buffer. It solely performs a pointer out-of-bounds check.
///
/// Also note that if the size of the memory buffer is unknown (<see cref="BufferSizeUnknown"/>,
/// only a lower-bounds check is performed.
/// </remarks>
public bool Contains(InputEvent* eventPtr)
{
if (eventPtr == null)
return false;
if (sizeInBytes == 0)
return false;
var bufferPtr = NativeArrayUnsafeUtility.GetUnsafeBufferPointerWithoutChecks(data);
if (eventPtr < bufferPtr)
return false;
if (sizeInBytes != BufferSizeUnknown && eventPtr >= (byte*)bufferPtr + sizeInBytes)
return false;
return true;
}
public void Reset()
{
m_EventCount = 0;
if (m_SizeInBytes != BufferSizeUnknown)
m_SizeInBytes = 0;
}
/// <summary>
/// Advance the read position to the next event in the buffer, preserving or not preserving the
/// current event depending on <paramref name="leaveEventInBuffer"/>.
/// </summary>
/// <param name="currentReadPos"></param>
/// <param name="currentWritePos"></param>
/// <param name="numEventsRetainedInBuffer"></param>
/// <param name="numRemainingEvents"></param>
/// <param name="leaveEventInBuffer"></param>
/// <remarks>
/// This method MUST ONLY BE CALLED if the current event has been fully processed. If the at <paramref name="currentWritePos"/>
/// is smaller than the current event, then this method will OVERWRITE parts or all of the current event.
/// </remarks>
internal void AdvanceToNextEvent(ref InputEvent* currentReadPos,
ref InputEvent* currentWritePos, ref int numEventsRetainedInBuffer,
ref int numRemainingEvents, bool leaveEventInBuffer)
{
Debug.Assert(currentReadPos >= currentWritePos, "Current write position is beyond read position");
// Get new read position *before* potentially moving the current event so that we don't
// end up overwriting the data we need to find the next event in memory.
var newReadPos = currentReadPos;
if (numRemainingEvents > 1)
{
// Don't perform safety check in non-debug builds.
#if UNITY_EDITOR || DEVELOPMENT_BUILD
newReadPos = InputEvent.GetNextInMemoryChecked(currentReadPos, ref this);
#else
newReadPos = InputEvent.GetNextInMemory(currentReadPos);
#endif
}
// If the current event should be left in the buffer, advance write position.
if (leaveEventInBuffer)
{
Debug.Assert(Contains(currentWritePos), "Current write position should be contained in buffer");
// Move down in buffer if read and write pos have deviated from each other.
var numBytes = currentReadPos->sizeInBytes;
if (currentReadPos != currentWritePos)
UnsafeUtility.MemMove(currentWritePos, currentReadPos, numBytes);
currentWritePos = (InputEvent*)((byte*)currentWritePos + numBytes.AlignToMultipleOf(4));
++numEventsRetainedInBuffer;
}
currentReadPos = newReadPos;
--numRemainingEvents;
}
public IEnumerator<InputEventPtr> GetEnumerator()
{
return new Enumerator(this);
}
IEnumerator IEnumerable.GetEnumerator()
{
return GetEnumerator();
}
public void Dispose()
{
// Nothing to do if we don't actually own the memory.
if (!m_WeOwnTheBuffer)
return;
Debug.Assert(m_Buffer.IsCreated, "Buffer has not been created");
m_Buffer.Dispose();
m_WeOwnTheBuffer = false;
m_SizeInBytes = 0;
m_EventCount = 0;
}
public InputEventBuffer Clone()
{
var clone = new InputEventBuffer();
if (m_Buffer.IsCreated)
{
clone.m_Buffer = new NativeArray<byte>(m_Buffer.Length, Allocator.Persistent);
clone.m_Buffer.CopyFrom(m_Buffer);
clone.m_WeOwnTheBuffer = true;
}
clone.m_SizeInBytes = m_SizeInBytes;
clone.m_EventCount = m_EventCount;
return clone;
}
object ICloneable.Clone()
{
return Clone();
}
private NativeArray<byte> m_Buffer;
private long m_SizeInBytes;
private int m_EventCount;
private bool m_WeOwnTheBuffer; ////FIXME: what we really want is access to NativeArray's allocator label
private struct Enumerator : IEnumerator<InputEventPtr>
{
private readonly InputEvent* m_Buffer;
private readonly int m_EventCount;
private InputEvent* m_CurrentEvent;
private int m_CurrentIndex;
public Enumerator(InputEventBuffer buffer)
{
m_Buffer = buffer.bufferPtr;
m_EventCount = buffer.m_EventCount;
m_CurrentEvent = null;
m_CurrentIndex = 0;
}
public bool MoveNext()
{
if (m_CurrentIndex == m_EventCount)
return false;
if (m_CurrentEvent == null)
{
m_CurrentEvent = m_Buffer;
return m_CurrentEvent != null;
}
Debug.Assert(m_CurrentEvent != null, "Current event must not be null");
++m_CurrentIndex;
if (m_CurrentIndex == m_EventCount)
return false;
m_CurrentEvent = InputEvent.GetNextInMemory(m_CurrentEvent);
return true;
}
public void Reset()
{
m_CurrentEvent = null;
m_CurrentIndex = 0;
}
public void Dispose()
{
}
public InputEventPtr Current => m_CurrentEvent;
object IEnumerator.Current => Current;
}
}
}