Audio rendering: reduce memory allocations (#6604)

* - WritableRegion: enable wrapping IMemoryOwner<byte>
- IVirtualMemoryManager impls of GetWritableRegion() use pooled memory when region is non-contiguous.
- IVirtualMemoryManager: add GetReadOnlySequence() and impls
- ByteMemoryPool: add new method RentCopy()
- ByteMemoryPool: make class static, remove ctor and singleton field from earlier impl

* - BytesReadOnlySequenceSegment: move from Ryujinx.Common.Memory to Ryujinx.Memory
- BytesReadOnlySequenceSegment: add IsContiguousWith() and Replace() methods
- VirtualMemoryManagerBase:
  - remove generic type parameters, instead use ulong for virtual addresses and nuint for host/physical addresses
  - implement IWritableBlock
  - add virtual GetReadOnlySequence() with coalescing of contiguous segments
  - add virtual GetSpan()
  - add virtual GetWritableRegion()
  - add abstract IsMapped()
  - add virtual MapForeign(ulong, nuint, ulong)
  - add virtual Read<T>()
  - add virtual Read(ulong, Span<byte>)
  - add virtual ReadTracked<T>()
  - add virtual SignalMemoryTracking()
  - add virtual Write()
  - add virtual Write<T>()
  - add virtual WriteUntracked()
  - add virtual WriteWithRedundancyCheck()
- VirtualMemoryManagerRefCountedBase: remove generic type parameters
- AddressSpaceManager: remove redundant methods, add required overrides
- HvMemoryManager: remove redundant methods, add required overrides, add overrides for _invalidAccessHandler handling
- MemoryManager: remove redundant methods, add required overrides, add overrides for _invalidAccessHandler handling
- MemoryManagerHostMapped: remove redundant methods, add required overrides, add overrides for _invalidAccessHandler handling
- NativeMemoryManager: add get properties for Pointer and Length
- throughout: removed invalid <inheritdoc/> comments

* - WritableRegion: enable wrapping IMemoryOwner<byte>
- IVirtualMemoryManager impls of GetWritableRegion() use pooled memory when region is non-contiguous.
- IVirtualMemoryManager: add GetReadOnlySequence() and impls
- ByteMemoryPool: add new method RentCopy()
- ByteMemoryPool: make class static, remove ctor and singleton field from earlier impl

* add PagedMemoryRange enumerator types, use them in IVirtualMemoryManager implementations to consolidate page-handling logic and add a new capability - the coalescing of pages for consolidating memory copies and segmentation.

* new: more tests for PagedMemoryRangeCoalescingEnumerator showing coalescing of contiguous segments

* make some struct properties readonly

* put braces around `foreach` bodies

* encourage inlining of some PagedMemoryRange*Enumerator members

* DynamicRingBuffer:
 - use ByteMemoryPool
 - make some methods return without locking when size/count argument = 0
 - make generic Read<T>()/Write<T>() non-generic because its only usage is as T = byte
 - change Read(byte[]...) to Read(Span<byte>...)
 - change Write(byte[]...) to Write(Span<byte>...)

* change IAudioRenderer.RequestUpdate() to take a ReadOnlySequence<byte>, enabling zero-copy audio rendering

* HipcGenerator: support ReadOnlySequence<byte> as IPC method parameter

* change IAudioRenderer/AudioRenderer RequestUpdate* methods to take input as ReadOnlySequence<byte>

* MemoryManagerHostTracked: use rented memory when contiguous in `GetWritableRegion()`

* rebase cleanup

* dotnet format fixes

* format and comment fixes

* format long parameter list - take 2

* - add support to HipcGenerator for buffers of type `Memory<byte>`
- change `AudioRenderer` `RequestUpdate()` and `RequestUpdateAuto()` to use Memory<byte> for output buffers, removing another memory block allocation/copy

* SplitterContext `UpdateState()` and `UpdateData()` smooth out advance/rewind logic, only rewind if magic is invalid

* DynamicRingBuffer.Write(): change Span<byte> to ReadOnlySpan<byte>

1 files changed, 181 insertions, 0 deletions

diff --git a/src/Ryujinx.Common/Extensions/SequenceReaderExtensions.cs b/src/Ryujinx.Common/Extensions/SequenceReaderExtensions.cs
new file mode 100644
index 00000000..5403c87c
--- /dev/null
+++ b/src/Ryujinx.Common/Extensions/SequenceReaderExtensions.cs
@@ -0,0 +1,181 @@
+using System;
+using System.Buffers;
+using System.Diagnostics;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.Common.Extensions
+{
+    public static class SequenceReaderExtensions
+    {
+        /// <summary>
+        /// Dumps the entire <see cref="SequenceReader{byte}"/> to a file, restoring its previous location afterward.
+        /// Useful for debugging purposes.
+        /// </summary>
+        /// <param name="reader">The <see cref="SequenceReader{Byte}"/> to write to a file</param>
+        /// <param name="fileFullName">The path and name of the file to create and dump to</param>
+        public static void DumpToFile(this ref SequenceReader<byte> reader, string fileFullName)
+        {
+            var initialConsumed = reader.Consumed;
+
+            reader.Rewind(initialConsumed);
+
+            using (var fileStream = System.IO.File.Create(fileFullName, 4096, System.IO.FileOptions.None))
+            {
+                while (reader.End == false)
+                {
+                    var span = reader.CurrentSpan;
+                    fileStream.Write(span);
+                    reader.Advance(span.Length);
+                }
+            }
+
+            reader.SetConsumed(initialConsumed);
+        }
+
+        /// <summary>
+        /// Returns a reference to the desired value. This ref should always be used. The argument passed in <paramref name="copyDestinationIfRequiredDoNotUse"/> should never be used, as this is only used for storage if the value
+        /// must be copied from multiple <see cref="ReadOnlyMemory{Byte}"/> segments held by the <see cref="SequenceReader{Byte}"/>.
+        /// </summary>
+        /// <typeparam name="T">Type to get</typeparam>
+        /// <param name="reader">The <see cref="SequenceReader{Byte}"/> to read from</param>
+        /// <param name="copyDestinationIfRequiredDoNotUse">A location used as storage if (and only if) the value to be read spans multiple <see cref="ReadOnlyMemory{Byte}"/> segments</param>
+        /// <returns>A reference to the desired value, either directly to memory in the <see cref="SequenceReader{Byte}"/>, or to <paramref name="copyDestinationIfRequiredDoNotUse"/> if it has been used for copying the value in to</returns>
+        /// <remarks>
+        /// DO NOT use <paramref name="copyDestinationIfRequiredDoNotUse"/> after calling this method, as it will only
+        /// contain a value if the value couldn't be referenced directly because it spans multiple <see cref="ReadOnlyMemory{Byte}"/> segments.
+        /// To discourage use, it is recommended to to call this method like the following:
+        /// <c>
+        ///     ref readonly MyStruct value = ref sequenceReader.GetRefOrRefToCopy{MyStruct}(out _);
+        /// </c>
+        /// </remarks>
+        /// <exception cref="ArgumentOutOfRangeException">The <see cref="SequenceReader{Byte}"/> does not contain enough data to read a value of type <typeparamref name="T"/></exception>
+        public static ref readonly T GetRefOrRefToCopy<T>(this scoped ref SequenceReader<byte> reader, out T copyDestinationIfRequiredDoNotUse) where T : unmanaged
+        {
+            int lengthRequired = Unsafe.SizeOf<T>();
+
+            ReadOnlySpan<byte> span = reader.UnreadSpan;
+            if (lengthRequired <= span.Length)
+            {
+                reader.Advance(lengthRequired);
+
+                copyDestinationIfRequiredDoNotUse = default;
+
+                ReadOnlySpan<T> spanOfT = MemoryMarshal.Cast<byte, T>(span);
+
+                return ref spanOfT[0];
+            }
+            else
+            {
+                copyDestinationIfRequiredDoNotUse = default;
+
+                Span<T> valueSpan = MemoryMarshal.CreateSpan(ref copyDestinationIfRequiredDoNotUse, 1);
+
+                Span<byte> valueBytesSpan = MemoryMarshal.AsBytes(valueSpan);
+
+                if (!reader.TryCopyTo(valueBytesSpan))
+                {
+                    throw new ArgumentOutOfRangeException(nameof(reader), "The sequence is not long enough to read the desired value.");
+                }
+
+                reader.Advance(lengthRequired);
+
+                return ref valueSpan[0];
+            }
+        }
+
+        /// <summary>
+        /// Reads an <see cref="int"/> as little endian.
+        /// </summary>
+        /// <param name="reader">The <see cref="SequenceReader{Byte}"/> to read from</param>
+        /// <param name="value">A location to receive the read value</param>
+        /// <exception cref="ArgumentOutOfRangeException">Thrown if there wasn't enough data for an <see cref="int"/></exception>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static void ReadLittleEndian(this ref SequenceReader<byte> reader, out int value)
+        {
+            if (!reader.TryReadLittleEndian(out value))
+            {
+                throw new ArgumentOutOfRangeException(nameof(value), "The sequence is not long enough to read the desired value.");
+            }
+        }
+
+        /// <summary>
+        /// Reads the desired unmanaged value by copying it to the specified <paramref name="value"/>.
+        /// </summary>
+        /// <typeparam name="T">Type to read</typeparam>
+        /// <param name="reader">The <see cref="SequenceReader{Byte}"/> to read from</param>
+        /// <param name="value">The target that will receive the read value</param>
+        /// <exception cref="ArgumentOutOfRangeException">The <see cref="SequenceReader{Byte}"/> does not contain enough data to read a value of type <typeparamref name="T"/></exception>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static void ReadUnmanaged<T>(this ref SequenceReader<byte> reader, out T value) where T : unmanaged
+        {
+            if (!reader.TryReadUnmanaged(out value))
+            {
+                throw new ArgumentOutOfRangeException(nameof(value), "The sequence is not long enough to read the desired value.");
+            }
+        }
+
+        /// <summary>
+        /// Sets the reader's position as bytes consumed.
+        /// </summary>
+        /// <param name="reader">The <see cref="SequenceReader{Byte}"/> to set the position</param>
+        /// <param name="consumed">The number of bytes consumed</param>
+        public static void SetConsumed(ref this SequenceReader<byte> reader, long consumed)
+        {
+            reader.Rewind(reader.Consumed);
+            reader.Advance(consumed);
+        }
+
+        /// <summary>
+        /// Try to read the given type out of the buffer if possible. Warning: this is dangerous to use with arbitrary
+        /// structs - see remarks for full details.
+        /// </summary>
+        /// <typeparam name="T">Type to read</typeparam>
+        /// <remarks>
+        /// IMPORTANT: The read is a straight copy of bits. If a struct depends on specific state of it's members to
+        /// behave correctly this can lead to exceptions, etc. If reading endian specific integers, use the explicit
+        /// overloads such as <see cref="SequenceReader{T}.TryReadLittleEndian"/>
+        /// </remarks>
+        /// <returns>
+        /// True if successful. <paramref name="value"/> will be default if failed (due to lack of space).
+        /// </returns>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static unsafe bool TryReadUnmanaged<T>(ref this SequenceReader<byte> reader, out T value) where T : unmanaged
+        {
+            ReadOnlySpan<byte> span = reader.UnreadSpan;
+
+            if (span.Length < sizeof(T))
+            {
+                return TryReadUnmanagedMultiSegment(ref reader, out value);
+            }
+
+            value = Unsafe.ReadUnaligned<T>(ref MemoryMarshal.GetReference(span));
+
+            reader.Advance(sizeof(T));
+
+            return true;
+        }
+
+        private static unsafe bool TryReadUnmanagedMultiSegment<T>(ref SequenceReader<byte> reader, out T value) where T : unmanaged
+        {
+            Debug.Assert(reader.UnreadSpan.Length < sizeof(T));
+
+            // Not enough data in the current segment, try to peek for the data we need.
+            T buffer = default;
+
+            Span<byte> tempSpan = new Span<byte>(&buffer, sizeof(T));
+
+            if (!reader.TryCopyTo(tempSpan))
+            {
+                value = default;
+                return false;
+            }
+
+            value = Unsafe.ReadUnaligned<T>(ref MemoryMarshal.GetReference(tempSpan));
+
+            reader.Advance(sizeof(T));
+
+            return true;
+        }
+    }
+}