Use Span<T> for APIs

SFML.Module.props

@@ -21,4 +21,8 @@
     <PackageReference Include="CSFML" Version="[3.0.0-rc.1, 3.1)" />
   </ItemGroup>
 
+  <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
+    <PackageReference Include="System.Memory" Version="4.6.0" />
+  </ItemGroup>
+
 </Project>

examples/opengl/OpenGL.cs

@@ -58,7 +58,7 @@ private static void Main()
             {
                 GL.GenTextures(1, out texture);
                 GL.BindTexture(TextureTarget.Texture2D, texture);
-                GL.TexImage2D(TextureTarget.Texture2D, 0, PixelInternalFormat.Rgba, (int)image.Size.X, (int)image.Size.Y, 0, PixelFormat.Rgba, PixelType.UnsignedByte, image.Pixels);
+                GL.TexImage2D(TextureTarget.Texture2D, 0, PixelInternalFormat.Rgba, (int)image.Size.X, (int)image.Size.Y, 0, PixelFormat.Rgba, PixelType.UnsignedByte, image.Pixels.ToArray());
                 GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMagFilter, (int)TextureMagFilter.Linear);
                 GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMinFilter, (int)TextureMinFilter.Linear);
             }

src/SFML.Audio/EffectProcessor.cs

@@ -84,8 +84,8 @@ namespace SFML.Audio
     /// occur.
     /// </summary>
     ////////////////////////////////////////////////////////////
-    public delegate long EffectProcessor(float[] inputFrames, float[] outputFrames, uint frameChannelCount);
+    public delegate long EffectProcessor(ReadOnlySpan<float> inputFrames, out uint inputFramesRead, Span<float> outputFrames, out uint outputFramesWritten, uint frameChannelCount);
 
     [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
-    internal delegate long EffectProcessorInternal(IntPtr inputFrames, uint inputFrameCount, IntPtr outputFrames, uint outputFrameCount, uint frameChannelCount);
+    internal unsafe delegate long EffectProcessorInternal(float* inputFrames, ref uint inputFrameCount, float* outputFrames, ref uint outputFrameCount, uint frameChannelCount);
 }

src/SFML.Audio/Music.cs

@@ -46,7 +46,7 @@ public Music(string filename) :
         /// </summary>
         /// <param name="stream">Source stream to read from</param>
         ////////////////////////////////////////////////////////////
-        public Music(Stream stream) :
+        public Music(Stream stream) :  // TODO this stream needs to stay alive
             base(IntPtr.Zero)
         {
             _stream = new StreamAdaptor(stream);
@@ -71,7 +71,7 @@ public Music(Stream stream) :
         /// <param name="bytes">Byte array containing the file contents</param>
         /// <exception cref="LoadingFailedException" />
         ////////////////////////////////////////////////////////////
-        public Music(byte[] bytes) :
+        public Music(byte[] bytes) :  // TODO this memory needs to stay alive
             base(IntPtr.Zero)
         {
             unsafe
@@ -140,21 +140,21 @@ public Music(byte[] bytes) :
         /// position during spatialisation.
         /// </summary>
         ////////////////////////////////////////////////////////////
-        public SoundChannel[] ChannelMap
+        public ReadOnlySpan<SoundChannel> ChannelMap
         {
             get
             {
                 unsafe
                 {
                     var channels = sfMusic_getChannelMap(CPointer, out var count);
-                    var arr = new SoundChannel[(int)count];
+                    Array.Resize(ref _channels, (int)count);
 
-                    for (var i = 0; i < arr.Length; i++)
+                    for (var i = 0; i < _channels.Length; i++)
                     {
-                        arr[i] = channels[i];
+                        _channels[i] = channels[i];
                     }
 
-                    return arr;
+                    return _channels;
                 }
             }
         }
@@ -498,17 +498,16 @@ public TimeSpan LoopPoints
         ////////////////////////////////////////////////////////////
         public void SetEffectProcessor(EffectProcessor effectProcessor)
         {
-            _effectProcessor = (inputFrames, inputFrameCount, outputFrames, outputFrameCount, frameChannelCount) =>
+            unsafe
             {
-                var inputFramesArray = new float[inputFrameCount];
-                var outputFramesArray = new float[outputFrameCount];
-
-                Marshal.Copy(inputFrames, inputFramesArray, 0, inputFramesArray.Length);
-                var written = effectProcessor(inputFramesArray, outputFramesArray, frameChannelCount);
-                Marshal.Copy(outputFramesArray, 0, outputFrames, outputFramesArray.Length);
+                _effectProcessor = (float* inputFrames, ref uint inputFrameCount, float* outputFrames, ref uint outputFrameCount, uint frameChannelCount) =>
+                {
+                    var inputBuffer = new ReadOnlySpan<float>(inputFrames, (int)inputFrameCount);
+                    var outputBuffer = new Span<float>(outputFrames, (int)outputFrameCount);
 
-                return written;
-            };
+                    return effectProcessor(inputBuffer, out inputFrameCount, outputBuffer, out outputFrameCount, frameChannelCount);
+                };
+            }
 
             sfMusic_setEffectProcessor(CPointer, Marshal.GetFunctionPointerForDelegate(_effectProcessor));
         }
@@ -560,6 +559,7 @@ protected override void Destroy(bool disposing)
 
         private readonly StreamAdaptor _stream;
         private EffectProcessorInternal _effectProcessor;
+        private SoundChannel[] _channels;
 
         /// <summary>
         /// Structure defining a Time range. 

src/SFML.Audio/Properties/PublishProfiles/FolderProfile.pubxml

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <!--
 This file is used by the publish/package process of your project. You can customize the behavior of this process
 by editing this MSBuild file. In order to learn more about this please visit https://go.microsoft.com/fwlink/?LinkID=208121. 
@@ -7,7 +7,7 @@ by editing this MSBuild file. In order to learn more about this please visit htt
   <PropertyGroup>
     <PublishProtocol>FileSystem</PublishProtocol>
     <Configuration>Release</Configuration>
-    <TargetFramework>netstandard2.0</TargetFramework>
+    <TargetFrameworks>netstandard2.0;netstandard2.1</TargetFrameworks>
     <PublishDir>bin\PublishOutput</PublishDir>
   </PropertyGroup>
 </Project>

src/SFML.Audio/SFML.Audio.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk" ToolsVersion="15.0">
 
   <PropertyGroup>
-    <TargetFramework>netstandard2.0</TargetFramework>
+    <TargetFrameworks>netstandard2.0;netstandard2.1</TargetFrameworks>
     <SFMLModule>Audio</SFMLModule>
     <Platforms>AnyCPU;x64;x86</Platforms>
   </PropertyGroup>

src/SFML.Audio/Sound.cs

@@ -403,17 +403,16 @@ public float Attenuation
         ////////////////////////////////////////////////////////////
         public void SetEffectProcessor(EffectProcessor effectProcessor)
         {
-            _effectProcessor = (inputFrames, inputFrameCount, outputFrames, outputFrameCount, frameChannelCount) =>
+            unsafe
             {
-                var inputFramesArray = new float[inputFrameCount];
-                var outputFramesArray = new float[outputFrameCount];
+                _effectProcessor = (float* inputFrames, ref uint inputFrameCount, float* outputFrames, ref uint outputFrameCount, uint frameChannelCount) =>
+                {
+                    var inputBuffer = new ReadOnlySpan<float>(inputFrames, (int)inputFrameCount);
+                    var outputBuffer = new Span<float>(outputFrames, (int)outputFrameCount);
 
-                Marshal.Copy(inputFrames, inputFramesArray, 0, inputFramesArray.Length);
-                var written = effectProcessor(inputFramesArray, outputFramesArray, frameChannelCount);
-                Marshal.Copy(outputFramesArray, 0, outputFrames, outputFramesArray.Length);
-
-                return written;
-            };
+                    return effectProcessor(inputBuffer, out inputFrameCount, outputBuffer, out outputFrameCount, frameChannelCount);
+                };
+            }
 
             sfSound_setEffectProcessor(CPointer, Marshal.GetFunctionPointerForDelegate(_effectProcessor));
         }

src/SFML.Audio/SoundBuffer.cs

@@ -69,7 +69,7 @@ public SoundBuffer(Stream stream) :
         /// <param name="bytes">Byte array containing the file contents</param>
         /// <exception cref="LoadingFailedException" />
         ////////////////////////////////////////////////////////////
-        public SoundBuffer(byte[] bytes) :
+        public SoundBuffer(ReadOnlySpan<byte> bytes) :
             base(IntPtr.Zero)
         {
             unsafe
@@ -96,7 +96,7 @@ public SoundBuffer(byte[] bytes) :
         /// <param name="channelMapData">Map of position in sample frame to sound channel</param>
         /// <exception cref="LoadingFailedException" />
         ////////////////////////////////////////////////////////////
-        public SoundBuffer(short[] samples, uint channelCount, uint sampleRate, SoundChannel[] channelMapData) :
+        public SoundBuffer(ReadOnlySpan<short> samples, uint channelCount, uint sampleRate, ReadOnlySpan<SoundChannel> channelMapData) :
             base(IntPtr.Zero)
         {
             unsafe
@@ -172,13 +172,17 @@ public SoundBuffer(SoundBuffer copy) :
         /// (sf::Int16).
         /// </summary>
         ////////////////////////////////////////////////////////////
-        public short[] Samples
+        public ReadOnlySpan<short> Samples
         {
             get
             {
-                var samplesArray = new short[sfSoundBuffer_getSampleCount(CPointer)];
-                Marshal.Copy(sfSoundBuffer_getSamples(CPointer), samplesArray, 0, samplesArray.Length);
-                return samplesArray;
+                unsafe
+                {
+                    // Sample array should remain constant and not get invalidated as a result
+                    var samplesCount = sfSoundBuffer_getSampleCount(CPointer);
+                    var samples = sfSoundBuffer_getSamples(CPointer);
+                    return new ReadOnlySpan<short>(samples.ToPointer(), (int)samplesCount);
+                }
             }
         }
 
@@ -190,21 +194,21 @@ public short[] Samples
         /// position during spatialisation.
         /// </summary>
         ////////////////////////////////////////////////////////////
-        public virtual SoundChannel[] ChannelMap
+        public virtual ReadOnlySpan<SoundChannel> ChannelMap
         {
             get
             {
                 unsafe
                 {
                     var channels = sfSoundBuffer_getChannelMap(CPointer, out var count);
-                    var arr = new SoundChannel[(int)count];
+                    Array.Resize(ref _channels, (int)count);
 
-                    for (var i = 0; i < arr.Length; i++)
+                    for (var i = 0; i < _channels.Length; i++)
                     {
-                        arr[i] = channels[i];
+                        _channels[i] = channels[i];
                     }
 
-                    return arr;
+                    return _channels;
                 }
             }
         }
@@ -236,6 +240,8 @@ public override string ToString()
         ////////////////////////////////////////////////////////////
         protected override void Destroy(bool disposing) => sfSoundBuffer_destroy(CPointer);
 
+        private SoundChannel[] _channels;
+
         #region Imports
         [DllImport(CSFML.Audio, CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
         private static extern IntPtr sfSoundBuffer_createFromFile(string filename);

src/SFML.Audio/SoundBufferRecorder.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 
 namespace SFML.Audio
@@ -59,9 +60,12 @@ protected override bool OnStart()
         /// <param name="samples">Array of samples to process</param>
         /// <returns>False to stop recording audio data, true to continue</returns>
         ////////////////////////////////////////////////////////////
-        protected override bool OnProcessSamples(short[] samples)
+        protected override bool OnProcessSamples(ReadOnlySpan<short> samples)
         {
-            _samplesArray.AddRange(samples);
+            for (var i = 0; i < samples.Length; i++)
+            {
+                _samplesArray.Add(samples[i]);
+            }
             return true;
         }
 

src/SFML.Audio/SoundRecorder.cs

@@ -97,21 +97,21 @@ public uint ChannelCount
         /// position during spatialisation.
         /// </summary>
         ////////////////////////////////////////////////////////////
-        public SoundChannel[] ChannelMap
+        public ReadOnlySpan<SoundChannel> ChannelMap
         {
             get
             {
                 unsafe
                 {
                     var channels = sfSoundRecorder_getChannelMap(CPointer, out var count);
-                    var arr = new SoundChannel[(int)count];
+                    Array.Resize(ref _channels, (int)count);
 
-                    for (var i = 0; i < arr.Length; i++)
+                    for (var i = 0; i < _channels.Length; i++)
                     {
-                        arr[i] = channels[i];
+                        _channels[i] = channels[i];
                     }
 
-                    return arr;
+                    return _channels;
                 }
             }
         }
@@ -173,7 +173,7 @@ protected virtual bool OnStart() =>
         /// <param name="samples">Array of samples to process</param>
         /// <returns>False to stop recording audio data, true to continue</returns>
         ////////////////////////////////////////////////////////////
-        protected abstract bool OnProcessSamples(short[] samples);
+        protected abstract bool OnProcessSamples(ReadOnlySpan<short> samples);
 
         ////////////////////////////////////////////////////////////
         /// <summary>
@@ -195,23 +195,25 @@ protected virtual void OnStop()
         /// Get the list of the names of all available audio capture devices
         /// </summary>
         ////////////////////////////////////////////////////////////
-        public static string[] AvailableDevices
+        public static ReadOnlySpan<string> AvailableDevices
         {
             get
             {
                 unsafe
                 {
                     var devicesPtr = sfSoundRecorder_getAvailableDevices(out var count);
-                    var devices = new string[(int)count];
-                    for (var i = 0; i < (int)count; ++i)
+                    Array.Resize(ref _availableDevices, (int)count);
+
+                    for (var i = 0; i < _availableDevices.Length; i++)
                     {
-                        devices[i] = Marshal.PtrToStringAnsi(devicesPtr[i]);
+                        _availableDevices[i] = Marshal.PtrToStringAnsi(devicesPtr[i]);
                     }
 
-                    return devices;
+                    return _availableDevices;
                 }
             }
         }
+        private static string[] _availableDevices;
 
         ////////////////////////////////////////////////////////////
         /// <summary>
@@ -267,10 +269,10 @@ public static string[] AvailableDevices
         ////////////////////////////////////////////////////////////
         private bool ProcessSamples(IntPtr samples, UIntPtr nbSamples, IntPtr userData)
         {
-            var samplesArray = new short[(int)nbSamples];
-            Marshal.Copy(samples, samplesArray, 0, samplesArray.Length);
-
-            return OnProcessSamples(samplesArray);
+            unsafe
+            {
+                return OnProcessSamples(new ReadOnlySpan<short>((void*)samples, (int)nbSamples));
+            }
         }
 
         ////////////////////////////////////////////////////////////
@@ -294,6 +296,7 @@ private bool ProcessSamples(IntPtr samples, UIntPtr nbSamples, IntPtr userData)
         private readonly StartCallback _startCallback;
         private readonly ProcessCallback _processCallback;
         private readonly StopCallback _stopCallback;
+        private SoundChannel[] _channels;
 
         #region Imports
         [DllImport(CSFML.Audio, CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]