audio: Rewrite SoundIo bindings (#4088)

* audio: Rewrite SoundIo bindings

This rewrite SoundIo bindings to be safer and not a pedantic autogenerated mess.

* Address comments

* Switch DllImport to LibraryImport

* Address gdkchan's comment

Ryujinx.Audio.Backends.SoundIo/Native/SoundIoOutStreamContext.cs

@@ -0,0 +1,164 @@
+using System;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+using static Ryujinx.Audio.Backends.SoundIo.Native.SoundIo;
+
+namespace Ryujinx.Audio.Backends.SoundIo.Native
+{
+    public class SoundIoOutStreamContext : IDisposable
+    {
+        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
+        private unsafe delegate void WriteCallbackDelegate(IntPtr ctx, int frameCountMin, int frameCountMax);
+
+        private IntPtr _context;
+        private IntPtr _nameStored;
+        private Action<int, int> _writeCallback;
+        private WriteCallbackDelegate _writeCallbackNative;
+
+        public IntPtr Context => _context;
+
+        internal SoundIoOutStreamContext(IntPtr context)
+        {
+            _context = context;
+            _nameStored = IntPtr.Zero;
+            _writeCallback = null;
+            _writeCallbackNative = null;
+        }
+
+        private ref SoundIoOutStream GetOutContext()
+        {
+            unsafe
+            {
+                return ref Unsafe.AsRef<SoundIoOutStream>((SoundIoOutStream*)_context);
+            }
+        }
+
+        public string Name
+        {
+            get => Marshal.PtrToStringAnsi(GetOutContext().Name);
+            set
+            {
+                var context = GetOutContext();
+
+                if (_nameStored != IntPtr.Zero && context.Name == _nameStored)
+                {
+                    Marshal.FreeHGlobal(_nameStored);
+                }
+
+                _nameStored = Marshal.StringToHGlobalAnsi(value);
+                GetOutContext().Name = _nameStored;
+            }
+        }
+
+        public SoundIoChannelLayout Layout
+        {
+            get => GetOutContext().Layout;
+            set => GetOutContext().Layout = value;
+        }
+
+        public SoundIoFormat Format
+        {
+            get => GetOutContext().Format;
+            set => GetOutContext().Format = value;
+        }
+
+        public int SampleRate
+        {
+            get => GetOutContext().SampleRate;
+            set => GetOutContext().SampleRate = value;
+        }
+
+        public float Volume
+        {
+            get => GetOutContext().Volume;
+            set => GetOutContext().Volume = value;
+        }
+
+        public int BytesPerFrame
+        {
+            get => GetOutContext().BytesPerFrame;
+            set => GetOutContext().BytesPerFrame = value;
+        }
+
+        public int BytesPerSample
+        {
+            get => GetOutContext().BytesPerSample;
+            set => GetOutContext().BytesPerSample = value;
+        }
+
+        public Action<int, int> WriteCallback
+        {
+            get { return _writeCallback; }
+            set
+            {
+                _writeCallback = value;
+
+                if (_writeCallback == null)
+                {
+                    _writeCallbackNative = null;
+                }
+                else
+                {
+                    _writeCallbackNative = (ctx, frameCountMin, frameCountMax) => _writeCallback(frameCountMin, frameCountMax);
+                }
+
+                GetOutContext().WriteCallback = Marshal.GetFunctionPointerForDelegate(_writeCallbackNative);
+            }
+        }
+
+        private static void CheckError(SoundIoError error)
+        {
+            if (error != SoundIoError.None)
+            {
+                throw new SoundIoException(error);
+            }
+        }
+
+        public void Open() => CheckError(soundio_outstream_open(_context));
+
+        public void Start() => CheckError(soundio_outstream_start(_context));
+
+        public void Pause(bool pause) => CheckError(soundio_outstream_pause(_context, pause));
+
+        public void SetVolume(double volume) => CheckError(soundio_outstream_set_volume(_context, volume));
+
+        public Span<SoundIoChannelArea> BeginWrite(ref int frameCount)
+        {
+            IntPtr arenas = default;
+            int nativeFrameCount = frameCount;
+
+            unsafe
+            {
+                var frameCountPtr = &nativeFrameCount;
+                var arenasPtr = &arenas;
+                CheckError(soundio_outstream_begin_write(_context, (IntPtr)arenasPtr, (IntPtr)frameCountPtr));
+
+                frameCount = *frameCountPtr;
+
+                return new Span<SoundIoChannelArea>((void*)arenas, Layout.ChannelCount);
+            }
+        }
+
+        public void EndWrite() => CheckError(soundio_outstream_end_write(_context));
+
+        protected virtual void Dispose(bool disposing)
+        {
+            if (_context != IntPtr.Zero)
+            {
+                soundio_outstream_destroy(_context);
+                _context = IntPtr.Zero;
+            }
+        }
+
+        public void Dispose()
+        {
+            Dispose(true);
+            GC.SuppressFinalize(this);
+        }
+
+        ~SoundIoOutStreamContext()
+        {
+            Dispose(false);
+        }
+    }
+}