Haydn: Part 1 (#2007)

* Haydn: Part 1

Based on my reverse of audio 11.0.0.

As always, core implementation under LGPLv3 for the same reasons as for Amadeus.

This place the bases of a more flexible audio system while making audout & audin accurate.

This have the following improvements:
- Complete reimplementation of audout and audin.
- Audin currently only have a dummy backend.
- Dramatically reduce CPU usage by up to 50% in common cases (SoundIO and OpenAL).
- Audio Renderer now can output to 5.1 devices when supported.
- Audio Renderer init its backend on demand instead of keeping two up all the time.
- All backends implementation are now in their own project.
- Ryujinx.Audio.Renderer was renamed Ryujinx.Audio and was refactored because of this.

As a note, games having issues with OpenAL haven't improved and will not
because of OpenAL design (stopping when buffers finish playing causing
possible audio "pops" when buffers are very small).

* Update for latest hexkyz's edits on Switchbrew

* audren: Rollback channel configuration changes

* Address gdkchan's comments

* Fix typo in OpenAL backend driver

* Address last comments

* Fix a nit

* Address gdkchan's comments

Ryujinx.Audio/Renderer/Common/WorkBufferAllocator.cs

@@ -0,0 +1,78 @@
+//
+// Copyright (c) 2019-2021 Ryujinx
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+//
+
+using Ryujinx.Audio.Renderer.Utils;
+using Ryujinx.Common;
+using System;
+using System.Diagnostics;
+using System.Runtime.CompilerServices;
+
+namespace Ryujinx.Audio.Renderer.Common
+{
+    public class WorkBufferAllocator
+    {
+        public Memory<byte> BackingMemory { get; }
+
+        public ulong Offset { get; private set; }
+
+        public WorkBufferAllocator(Memory<byte> backingMemory)
+        {
+            BackingMemory = backingMemory;
+        }
+
+        public Memory<byte> Allocate(ulong size, int align)
+        {
+            Debug.Assert(align != 0);
+
+            if (size != 0)
+            {
+                ulong alignedOffset = BitUtils.AlignUp(Offset, align);
+
+                if (alignedOffset + size <= (ulong)BackingMemory.Length)
+                {
+                    Memory<byte> result = BackingMemory.Slice((int)alignedOffset, (int)size);
+
+                    Offset = alignedOffset + size;
+
+                    // Clear the memory to be sure that is does not contain any garbage.
+                    result.Span.Fill(0);
+
+                    return result;
+                }
+            }
+
+            return Memory<byte>.Empty;
+        }
+
+        public Memory<T> Allocate<T>(ulong count, int align) where T: unmanaged
+        {
+            Memory<byte> allocatedMemory = Allocate((ulong)Unsafe.SizeOf<T>() * count, align);
+
+            if (allocatedMemory.IsEmpty)
+            {
+                return Memory<T>.Empty;
+            }
+
+            return SpanMemoryManager<T>.Cast(allocatedMemory);
+        }
+
+        public static ulong GetTargetSize<T>(ulong currentSize, ulong count, int align) where T: unmanaged
+        {
+            return BitUtils.AlignUp(currentSize, align) + (ulong)Unsafe.SizeOf<T>() * count;
+        }
+    }
+}