第一種作法, c++指標到c#從IntPtr轉換成byte後再依照自己的指定順序塞進結構中

1.cpp

PLUGIN_DLL_API const void* GetDataPtr(const int data_id, int &length)
  {
    length = sizeof(Data);

    const Data* Dta = ... // 資料來源
    if (NULL == Dta)
    {
      return NULL;
    }

    return (const void*)Dta;
  }

1.cs

[DllImport(PlatformDllName)]
private static extern System.IntPtr GetDataPtr(int data_id, ref int Length);

public static byte[] GetDataBytes(int data_id)
{
  int Length = 0;
  System.IntPtr ptr = GetDataPtr(data_id, ref Length);
  if (ptr == System.IntPtr.Zero)
  {
    return null;
  }
  byte[] Source = new byte[Length];
  Marshal.Copy(ptr, Source, 0, Length);
  return Source;
}

public static Data BytesToData(byte[] Source)
{
  Data Dta = new Data();
  unsafe
  {
    fixed (byte* pbuffer = Source)
    {
      byte* scan = pbuffer;
      GetBuffByte(ref Dta.m_OpenFlag, ref scan);
      GetBuffInt(ref Dta.m_ID, ref Source, ref scan, pbuffer);
      GetBuffByte(ref Dta.m_ShowFlag, ref scan);
      GetBuffInt(ref Dta.m_BuildType, ref Source, ref scan, pbuffer);
      GetBuffInt(ref Dta.m_NameID, ref Source, ref scan, pbuffer);
      GetBuffInt(ref Dta.m_DescriptionID, ref Source, ref scan, pbuffer);
      GetBuffInt(ref Dta.m_BuildLV, ref Source, ref scan, pbuffer);
      GetBuffInt(ref Dta.m_Group, ref Source, ref scan, pbuffer);


      GetBuffString(ref Dta.m_IconName, ref Source, ref scan, pbuffer, 100);
      GetBuffInt16(ref Dta.m_TestInt16, ref Source, ref scan, pbuffer);
      GetBuffInt64(ref Dta.m_TestInt64, ref Source, ref scan, pbuffer);
      GetBuffUInt16(ref Dta.m_TestUInt16, ref Source, ref scan, pbuffer);
      GetBuffUInt64(ref Dta.m_TestUInt64, ref Source, ref scan, pbuffer);
      GetBuffIntPtr(ref Dta.m_TestInt16Vec, ref Source, ref scan, pbuffer);

      GetBuffIntAry(ref Dta.m_FrontBuildID, ref Source, ref scan, pbuffer);
      GetBuffIntAry(ref Dta.m_FrontTechID, ref Source, ref scan, pbuffer);
      GetBuffIntAry(ref Dta.m_UpCostType, ref Source, ref scan, pbuffer);
      GetBuffIntAry(ref Dta.m_UpCostValue, ref Source, ref scan, pbuffer);
      GetBuffInt(ref Dta.m_BuildTime, ref Source, ref scan, pbuffer);
      GetBuffIntAry(ref Dta.m_BuildBuffID, ref Source, ref scan, pbuffer);
      GetBuffIntAry(ref Dta.m_BuildBuffIDPlus, ref Source, ref scan, pbuffer);
      GetBuffInt(ref Dta.m_BuildFightBuffType, ref Source, ref scan, pbuffer);
      GetBuffInt(ref Dta.m_BuildFightBuffValue, ref Source, ref scan, pbuffer);
      GetBuffInt(ref Dta.m_BuildShipID, ref Source, ref scan, pbuffer);
      GetBuffString(ref Dta.m_FileName, ref Source, ref scan, pbuffer, 100);
      GetBuffString(ref Dta.m_PrefabResPathLow, ref Source, ref scan, pbuffer, 100);
      GetBuffFloat(ref Dta.m_PrefabLowSize, ref Source, ref scan, pbuffer);
      GetBuffString(ref Dta.m_PrefabResPathHigh, ref Source, ref scan, pbuffer, 100);
      GetBuffFloat(ref Dta.m_PrefabHighSize, ref Source, ref scan, pbuffer);
      GetBuffString(ref Dta.m_UIStaticDisplay, ref Source, ref scan, pbuffer, 100);
      GetBuffFloat(ref Dta.m_UIDisplaySize, ref Source, ref scan, pbuffer);
      GetBuffIntPtr(ref Dta.m_TestUInt16Vec, ref Source, ref scan, pbuffer);
    }
  }

  return Dta;
}

static unsafe void GetBuffIntPtr(ref IntPtr Target, ref byte[] array, ref byte* scan, byte* Origin)
{
  if (Marshal.SizeOf(typeof(IntPtr)) == 8)
  {
    Target = (IntPtr)System.BitConverter.ToUInt64(array, (int)(scan - Origin));
    scan += 8;
  }
  else
  {
    Target = (IntPtr)System.BitConverter.ToUInt32(array, (int)(scan - Origin));
    scan += 4;
  }
}


static unsafe void GetBuffInt16(ref Int16 Target, ref byte[] array, ref byte* scan, byte* Origin)
{
  Target = System.BitConverter.ToInt16(array, (int)(scan - Origin));
  scan += 2;
}
static unsafe void GetBuffInt16Ary(ref Int16[] Target, ref byte[] array, ref byte* scan, byte* Origin)
{
  for (int i = 0; i < Target.Length; ++i)
  {
    Target[i] = System.BitConverter.ToInt16(array, (int)(scan - Origin));
    scan += 2;
  }
}

static unsafe void GetBuffInt64(ref Int64 Target, ref byte[] array, ref byte* scan, byte* Origin)
{
  Target = System.BitConverter.ToInt64(array, (int)(scan - Origin));
  scan += 8;
}
static unsafe void GetBuffUInt16(ref UInt16 Target, ref byte[] array, ref byte* scan, byte* Origin)
{
  Target = System.BitConverter.ToUInt16(array, (int)(scan - Origin));
  scan += 2;
}
static unsafe void GetBuffUInt64(ref UInt64 Target, ref byte[] array, ref byte* scan, byte* Origin)
{
  Target = System.BitConverter.ToUInt64(array, (int)(scan - Origin));
  scan += 8;
}


static unsafe void GetBuffInt(ref int Target, ref byte[] array, ref byte* scan, byte* Origin)
{
  Target = System.BitConverter.ToInt32(array, (int)(scan - Origin));
  scan += 4;
}

static unsafe void GetBuffIntAry(ref int[] Target, ref byte[] array, ref byte* scan, byte* Origin)
{
  for (int i = 0; i < Target.Length; ++i)
  {
    Target[i] = System.BitConverter.ToInt32(array, (int)(scan - Origin));
    scan += 4;
  }
}

static unsafe void GetBuffByte(ref byte Target, ref byte* scan)
{
  byte[] a = new byte[1];
  a[0] = *(byte*)(scan);
  UnityEngine.Debug.Log(System.BitConverter.ToString(a));
  Target = *(byte*)(scan);
  scan += 1;
}

static unsafe void GetBuffFloat(ref float Target, ref byte[] array, ref byte* scan, byte* Origin)
{

  byte[] Tmp = new byte[4];
  Tmp[0] = array[(int)(scan - Origin) + 0];
  Tmp[1] = array[(int)(scan - Origin) + 1];
  Tmp[2] = array[(int)(scan - Origin) + 2];
  Tmp[3] = array[(int)(scan - Origin) + 3];

  UnityEngine.Debug.Log("GetBuffFloat_1_" + System.BitConverter.ToString(Tmp));
  Target = System.BitConverter.ToSingle(array, (int)(scan - Origin));
  UnityEngine.Debug.Log("GetBuffFloat_2_" + System.BitConverter.ToString(System.BitConverter.GetBytes(Target)));
  scan += 4;
}

static unsafe void GetBuffString(ref string Target, ref byte[] array, ref byte* scan, byte* Origin, int ByteSize)
{
  //
  //  這樣的作法要自己找字串結尾..
  //

  Target = (Encoding.UTF8.GetString(array, (int)(scan - Origin), ByteSize));
  //Target = Target.TrimEnd('\0');
  int i = Target.IndexOf('\0');
  if (i >= 0) Target = Target.Substring(0, i);
  
  scan += ByteSize;
}