c# - 通过 Net Core 将 C++ 数组传递到 C# 层

Question

我有一个 native 库，我想做的是为这个 native 库编写一个 .NET Core 包装器。

在 native 方面，我有一个名为 OnSpeechEnded 的事件:

virtual void OnSpeechEnded(SpeechEndInfo seInfo) = 0;

和原生结构 SpeechEndInfo 具有以下结构:

struct SpeechEndInfo
{
    std::vector<AudioData> UntouchedData;
    std::vector<AudioData> AudioAfterPostSpeechUntilSilenceTrigger;
};

对应的 .NET 标准类:

 public struct SpeechEndedInfo
    {
        public SpeechEndedInfo(short[] untouchedData, short[] audioAfterPostSpeechUntilSilenceTrigger)
        {
            UntouchedData = new short[untouchedData.Length];
            untouchedData.CopyTo(UntouchedData, 0);


            AudioAfterPostSpeechUntilSilenceTrigger = new short[audioAfterPostSpeechUntilSilenceTrigger.Length];
            audioAfterPostSpeechUntilSilenceTrigger.CopyTo(AudioAfterPostSpeechUntilSilenceTrigger, 0);


        }

        public short[] UntouchedData { get; set; }
        public short[] AudioAfterPostSpeechUntilSilenceTrigger { get; set; }
    };

在 .NET Standard 端，定义了以下委托(delegate):

delegate void OnSpeechEndedInter(
            [In, MarshalAs(UnmanagedType.LPArray)] short[] untouched, 
            int untouchedSize, 
            [In, MarshalAs(UnmanagedType.LPArray)] short[] audioAfterPostSpeechUntilSilenceTrigger,
            int audioAfterPostSpeechUntilSilenceTriggerSize);

声明pinvoke:

[DllImport("VadLite.Pinvokable.dll", CallingConvention = CallingConvention.Cdecl)]
        private static extern void RegisterToSpeechEndedEvent(IntPtr parameters, [MarshalAs(UnmanagedType.FunctionPtr)]OnSpeechEndedInter onSpeechEndedInter);

声明 _onSpeechEndedInter:

 private OnSpeechEndedInter _onSpeechEndedInter;

为事件分配一个方法:

 _onSpeechEndedInter = invokedMethod;

...

void invokedMethod(short[] untouchedData, 
            int untouchedSize, 
            short[] audioAfterPostSpeechUntilSilenceTrigger,
            int audioAfterPostSpeechUntilSilenceTriggerSize)
        {
            OnSpeechEnded?.Invoke(new SpeechEndedInfo(untouchedData, audioAfterPostSpeechUntilSilenceTrigger));
        }

最后是发送原生数组的代码:

RegisterToSpeechEndedEvent(
        void * possiblyOperations,
        void __stdcall onSpeechEndedListener(const int16_t* pUntouchedData, int pUntouchedDataSize, const int16_t *vAudioAfterPostSpeechUntilSilenceTrigger, int vAudioAfterPostSpeechUntilSilenceTriggerSize))
    {

        auto op = (OperationParameters *)possiblyOperations;
        op->OnSpeechEnded([onSpeechEndedListener](SpeechEndInfo ssInfo) {


            std::vector<int16_t> untouchedData;
            std::vector<int16_t> audioAfterPostSpeechUntilSilenceTrigger;

            for (auto & audioData : ssInfo.UntouchedData)
            {
                untouchedData.insert(untouchedData.end(), audioData.Samples, audioData.Samples + audioData.SampleCount);
            }


            for (auto & audioData : ssInfo.AudioAfterPostSpeechUntilSilenceTrigger)
            {
                audioAfterPostSpeechUntilSilenceTrigger.insert(audioAfterPostSpeechUntilSilenceTrigger.end(), audioData.Samples, audioData.Samples + audioData.SampleCount);
            }



            onSpeechEndedListener(untouchedData.empty() ? nullptr : untouchedData.data(),
                    (int)untouchedData.size(),
                    audioAfterPostSpeechUntilSilenceTrigger.empty() ? nullptr : audioAfterPostSpeechUntilSilenceTrigger.data(),
                    (int)audioAfterPostSpeechUntilSilenceTrigger.size());

        });

在运行测试程序并在 native 端获得有意义的数组大小后，C# 数组 UntouchedData 和 AudioAfterPostSpeechUntilSilenceTrigger 的大小似乎始终为 1。

可能有一个细节我错过了。如果需要，我可以提供更多详细信息。谢谢。

Answer 1

太棒了!我终于找到问题所在了。在委托(delegate)声明中，我只需要引入参数 SizeParamIndex :

delegate void OnSpeechEndedInter(
            [In, MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 1)] short[] untouched, 
            int untouchedSize, 
            [In, MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 3)] short[] audioAfterPostSpeechUntilSilenceTrigger,
            int audioAfterPostSpeechUntilSilenceTriggerSize);

因为编码(marshal)拆收器无法确定非托管数组的大小，考虑到方法的签名和基于零的索引，我们必须将其作为单独的参数传入。