/// <summary>
/// Inits the vTable method from GUID. This is a tricky part of this class.
/// </summary>
/// <param name="ASIOGuid">The ASIO GUID.</param>
private void initFromGuid(Guid ASIOGuid)
{
const uint CLSCTX_INPROC_SERVER = 1;
// Start to query the virtual table a index 3 (init method of ASIODriver)
const int INDEX_VTABLE_FIRST_METHOD = 3;
// Pointer to the ASIO object
// USE CoCreateInstance instead of builtin COM-Class instantiation,
// because the ASIODriver expect to have the ASIOGuid used for both COM Object and COM interface
// The CoCreateInstance is working only in STAThread mode.
int hresult = CoCreateInstance(ref ASIOGuid, IntPtr.Zero, CLSCTX_INPROC_SERVER, ref ASIOGuid, out pASIOComObject);
if (hresult != 0)
{
throw new COMException("Unable to instantiate ASIO. Check if STAThread is set", hresult);
}
// The first pointer at the adress of the ASIO Com Object is a pointer to the
// C++ Virtual table of the object.
// Gets a pointer to VTable.
IntPtr pVtable = Marshal.ReadIntPtr(pASIOComObject);
// Instantiate our Virtual table mapping
asioDriverVTable = new ASIODriverVTable();
// This loop is going to retrieve the pointer from the C++ VirtualTable
// and attach an internal delegate in order to call the method on the COM Object.
FieldInfo[] fieldInfos = typeof(ASIODriverVTable).GetFields();
for (int i = 0; i < fieldInfos.Length; i++)
{
FieldInfo fieldInfo = fieldInfos[i];
// Read the method pointer from the VTable
IntPtr pPointerToMethodInVTable = Marshal.ReadIntPtr(pVtable, (i + INDEX_VTABLE_FIRST_METHOD) * IntPtr.Size);
// Instantiate a delegate
object methodDelegate = Marshal.GetDelegateForFunctionPointer(pPointerToMethodInVTable, fieldInfo.FieldType);
// Store the delegate in our C# VTable
fieldInfo.SetValue(asioDriverVTable, methodDelegate);
}
}
/// <summary>
/// Inits the vTable method from GUID. This is a tricky part of this class.
/// </summary>
/// <param name="ASIOGuid">The ASIO GUID.</param>
private void initFromGuid(Guid ASIOGuid)
{
const uint CLSCTX_INPROC_SERVER = 1;
// Start to query the virtual table a index 3 (init method of ASIODriver)
const int INDEX_VTABLE_FIRST_METHOD = 3;
// Pointer to the ASIO object
// USE CoCreateInstance instead of builtin COM-Class instantiation,
// because the ASIODriver expect to have the ASIOGuid used for both COM Object and COM interface
// The CoCreateInstance is working only in STAThread mode.
int hresult = CoCreateInstance(ref ASIOGuid, IntPtr.Zero, CLSCTX_INPROC_SERVER, ref ASIOGuid, out pASIOComObject);
if ( hresult != 0 )
{
throw new COMException("Unable to instantiate ASIO. Check if STAThread is set",hresult);
}
// The first pointer at the adress of the ASIO Com Object is a pointer to the
// C++ Virtual table of the object.
// Gets a pointer to VTable.
IntPtr pVtable = Marshal.ReadIntPtr(pASIOComObject);
// Instantiate our Virtual table mapping
asioDriverVTable = new ASIODriverVTable();
// This loop is going to retrieve the pointer from the C++ VirtualTable
// and attach an internal delegate in order to call the method on the COM Object.
FieldInfo[] fieldInfos = typeof (ASIODriverVTable).GetFields();
for (int i = 0; i < fieldInfos.Length; i++)
{
FieldInfo fieldInfo = fieldInfos[i];
// Read the method pointer from the VTable
IntPtr pPointerToMethodInVTable = Marshal.ReadIntPtr(pVtable, (i + INDEX_VTABLE_FIRST_METHOD) * IntPtr.Size);
// Instantiate a delegate
object methodDelegate = Marshal.GetDelegateForFunctionPointer(pPointerToMethodInVTable, fieldInfo.FieldType);
// Store the delegate in our C# VTable
fieldInfo.SetValue(asioDriverVTable, methodDelegate);
}
}
