FFmpeg abstractions API (#227)

* First prototype

* First - something is working version

* Drop old generator and update example to use new packages

* simplify bindings

* Working version

* Test Dynamically Linked version

* Working version

* Add bsf.h

* FunctionLoader -> FunctionResolver

* Fix typo

* Fix namings

* Add in modifier for const fixed arrays #221

* Fix build warnings

* Fix example project

* Improve solution navigation

Co-authored-by: Ruslan Balanukhin <[email protected]>

Author: Ruslan-B

.gitignore

@@ -106,4 +106,8 @@ UpgradeLog*.XML
 *.stackdump
 
 # Local 
-/FFmpeg.AutoGen.Example/frame.*.jpg
+/FFmpeg.AutoGen.Example/frames
+
+# JetBrains Rider
+.idea/
+*.sln.iml

Directory.Build.props

@@ -1,11 +1,11 @@
 <Project>
   <PropertyGroup>
     <PackageId>$(AssemblyName)</PackageId>
-    <Version>5.1.1</Version>
+    <Version>5.1.1.1</Version>
     <Authors>Ruslan Balanukhin</Authors>
-    <Company>Rational Core</Company>
+    <Company>Rationale One</Company>
     <Product>FFmpeg.AutoGen</Product>
-    <Copyright>Copyright © Ruslan Balanukhin 2021 All rights reserved.</Copyright>
+    <Copyright>Copyright © Ruslan Balanukhin 2022 All rights reserved.</Copyright>
     <PackageProjectUrl>https://github.com/Ruslan-B/FFmpeg.AutoGen</PackageProjectUrl>
     <RepositoryType>Git</RepositoryType>
     <AssemblyVersion>$(Version)</AssemblyVersion>
@@ -16,7 +16,8 @@
   </PropertyGroup>
 
   <PropertyGroup>
-    <PublicSign Condition="'$(OS)' != 'Windows_NT'">true</PublicSign>
+    <!--<PublicSign Condition="'$(OS)' != 'Windows_NT'">true</PublicSign>-->
+    <PublicSign>true</PublicSign>
     <SignAssembly>true</SignAssembly>
     <DelaySign>false</DelaySign>
     <AssemblyOriginatorKeyFile>$(MSBuildThisFileDirectory)FFmpeg.AutoGen.snk</AssemblyOriginatorKeyFile>

FFmpeg.AutoGen.Abstractions/ConstCharPtrMarshaler.cs

@@ -0,0 +1,24 @@
+using System;
+using System.Runtime.InteropServices;
+
+namespace FFmpeg.AutoGen.Abstractions;
+
+public class ConstCharPtrMarshaler : ICustomMarshaler
+{
+    private static readonly ConstCharPtrMarshaler Instance = new();
+    public object MarshalNativeToManaged(IntPtr pNativeData) => Marshal.PtrToStringAnsi(pNativeData);
+
+    public IntPtr MarshalManagedToNative(object managedObj) => IntPtr.Zero;
+
+    public void CleanUpNativeData(IntPtr pNativeData)
+    {
+    }
+
+    public void CleanUpManagedData(object managedObj)
+    {
+    }
+
+    public int GetNativeDataSize() => IntPtr.Size;
+
+    public static ICustomMarshaler GetInstance(string cookie) => Instance;
+}

FFmpeg.AutoGen.Abstractions/FFmpeg.AutoGen.Abstractions.csproj

@@ -0,0 +1,31 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFrameworks>netstandard2.1;netstandard2.0;net45</TargetFrameworks>
+    <Description>FFmpeg auto generated unsafe bindings for C#/.NET and Mono. Abstractions todo</Description>
+    <GeneratePackageOnBuild Condition=" $(Configuration) == 'Release' ">true</GeneratePackageOnBuild>
+  </PropertyGroup>
+
+  <PropertyGroup>
+    <AllowUnsafeBlocks>True</AllowUnsafeBlocks>
+    <NoWarn>108;169;612;618;1573;1591;1701;1702;1705</NoWarn>
+    <TreatWarningsAsErrors>false</TreatWarningsAsErrors>
+    <WarningsAsErrors />
+    <DocumentationFile>bin\$(Configuration)\$(TargetFramework)\$(AssemblyName).xml</DocumentationFile>
+  </PropertyGroup>
+
+  <PropertyGroup>
+    <!-- Build symbol package (.snupkg) to distribute the PDB containing Source Link -->
+    <IncludeSymbols>true</IncludeSymbols>
+    <SymbolPackageFormat>snupkg</SymbolPackageFormat>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.1.1" PrivateAssets="all" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Update="Microsoft.Net.Compilers.Toolset" Version="4.2.0" />
+  </ItemGroup>
+
+</Project>

FFmpeg.AutoGen.Abstractions/FFmpeg.cs

@@ -0,0 +1,49 @@
+using System;
+using System.Runtime.InteropServices;
+
+namespace FFmpeg.AutoGen.Abstractions;
+
+public static partial class ffmpeg
+{
+    public static readonly int EAGAIN;
+
+    public static readonly int ENOMEM = 12;
+
+    public static readonly int EINVAL = 22;
+
+    public static readonly int EPIPE = 32;
+    
+    static ffmpeg()
+    {
+#if NET
+
+#elif NETSTANDARD2_0_OR_GREATER
+        EAGAIN = RuntimeInformation.IsOSPlatform(OSPlatform.OSX) ? 35 : 11;
+#else
+        EAGAIN = Environment.OSVersion.Platform == PlatformID.MacOSX ? 35 : 11;
+#endif
+
+    }
+
+    public static ulong UINT64_C<T>(T a)
+        => Convert.ToUInt64(a);
+
+    public static int AVERROR<T1>(T1 a)
+        => -Convert.ToInt32(a);
+
+    public static int MKTAG<T1, T2, T3, T4>(T1 a, T2 b, T3 c, T4 d)
+        => (int)(Convert.ToUInt32(a) | (Convert.ToUInt32(b) << 8) | (Convert.ToUInt32(c) << 16) |
+                 (Convert.ToUInt32(d) << 24));
+
+    public static int FFERRTAG<T1, T2, T3, T4>(T1 a, T2 b, T3 c, T4 d)
+        => -MKTAG(a, b, c, d);
+
+    public static int AV_VERSION_INT<T1, T2, T3>(T1 a, T2 b, T3 c) =>
+        (Convert.ToInt32(a) << 16) | (Convert.ToInt32(b) << 8) | Convert.ToInt32(c);
+
+    public static string AV_VERSION_DOT<T1, T2, T3>(T1 a, T2 b, T3 c)
+        => $"{a}.{b}.{c}";
+
+    public static string AV_VERSION<T1, T2, T3>(T1 a, T2 b, T3 c)
+        => AV_VERSION_DOT(a, b, c);
+}

FFmpeg.AutoGen.Abstractions/IFixedArray.cs

@@ -0,0 +1,13 @@
+namespace FFmpeg.AutoGen.Abstractions;
+
+public interface IFixedArray
+{
+    int Length { get; }
+}
+
+internal interface IFixedArray<T> : IFixedArray
+{
+    T this[uint index] { get; set; }
+    T[] ToArray();
+    void UpdateFrom(T[] array);
+}

FFmpeg.AutoGen.Abstractions/UTF8Marshaler.cs

@@ -0,0 +1,82 @@
+using System;
+using System.Runtime.InteropServices;
+using System.Text;
+
+namespace FFmpeg.AutoGen.Abstractions;
+
+public class UTF8Marshaler : ICustomMarshaler
+{
+    private static readonly UTF8Marshaler Instance = new();
+
+    public virtual object MarshalNativeToManaged(IntPtr pNativeData) => FromNative(Encoding.UTF8, pNativeData);
+
+    public virtual IntPtr MarshalManagedToNative(object managedObj)
+    {
+        if (managedObj == null)
+            return IntPtr.Zero;
+
+        if (managedObj is not string str)
+            throw new MarshalDirectiveException($"{GetType().Name} must be used on a string.");
+
+        return FromManaged(Encoding.UTF8, str);
+    }
+
+    public virtual void CleanUpNativeData(IntPtr pNativeData)
+    {
+        //Free anything allocated by MarshalManagedToNative
+        //This is called after the native function call completes
+
+        if (pNativeData != IntPtr.Zero)
+            Marshal.FreeHGlobal(pNativeData);
+    }
+
+    public void CleanUpManagedData(object managedObj)
+    {
+        //Free anything allocated by MarshalNativeToManaged
+        //This is called after the native function call completes
+    }
+
+    public int GetNativeDataSize() => -1; // Not a value type
+
+    public static ICustomMarshaler GetInstance(string cookie) => Instance;
+
+    public static unsafe string FromNative(Encoding encoding, IntPtr pNativeData) => FromNative(encoding, (byte*)pNativeData);
+
+    public static unsafe string FromNative(Encoding encoding, byte* pNativeData)
+    {
+        if (pNativeData == null)
+            return null;
+
+        var start = pNativeData;
+        var walk = start;
+
+        // Find the end of the string
+        while (*walk != 0) walk++;
+
+        if (walk == start)
+            return string.Empty;
+
+        return new string((sbyte*)pNativeData, 0, (int)(walk - start), encoding);
+    }
+
+    public static unsafe IntPtr FromManaged(Encoding encoding, string value)
+    {
+        if (encoding == null || value == null)
+            return IntPtr.Zero;
+
+        var length = encoding.GetByteCount(value);
+        var buffer = (byte*)Marshal.AllocHGlobal(length + 1).ToPointer();
+
+        if (length > 0)
+        {
+            fixed (char* pValue = value)
+            {
+                encoding.GetBytes(pValue, value.Length, buffer, length);
+            }
+        }
+
+        buffer[length] = 0;
+
+        return new IntPtr(buffer);
+    }
+}