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// ****************************************************************************
// File: IASIOThiscallResolver.h
// Description: The IASIOThiscallResolver class implements the IASIO
// interface and acts as a proxy to the real IASIO interface by
// calling through its vptr table using the thiscall calling
// convention. To put it another way, we interpose
// IASIOThiscallResolver between ASIO SDK code and the driver.
// This is necessary because most non-Microsoft compilers don't
// implement the thiscall calling convention used by IASIO.
//
// iasiothiscallresolver.cpp contains the background of this
// problem plus a technical description of the vptr
// manipulations.
//
// In order to use this mechanism one simply has to add
// iasiothiscallresolver.cpp to the list of files to compile
// and #include <iasiothiscallresolver.h>
//
// Note that this #include must come after the other ASIO SDK
// #includes, for example:
//
// #include <windows.h>
// #include <asiosys.h>
// #include <asio.h>
// #include <asiodrivers.h>
// #include <iasiothiscallresolver.h>
//
// Actually the important thing is to #include
// <iasiothiscallresolver.h> after <asio.h>. We have
// incorporated a test to enforce this ordering.
//
// The code transparently takes care of the interposition by
// using macro substitution to intercept calls to ASIOInit()
// and ASIOExit(). We save the original ASIO global
// "theAsioDriver" in our "that" variable, and then set
// "theAsioDriver" to equal our IASIOThiscallResolver instance.
//
// Whilst this method of resolving the thiscall problem requires
// the addition of #include <iasiothiscallresolver.h> to client
// code it has the advantage that it does not break the terms
// of the ASIO licence by publishing it. We are NOT modifying
// any Steinberg code here, we are merely implementing the IASIO
// interface in the same way that we would need to do if we
// wished to provide an open source ASIO driver.
//
// For compilation with MinGW -lole32 needs to be added to the
// linker options. For BORLAND, linking with Import32.lib is
// sufficient.
//
// The dependencies are with: CoInitialize, CoUninitialize,
// CoCreateInstance, CLSIDFromString - used by asiolist.cpp
// and are required on Windows whether ThiscallResolver is used
// or not.
//
// Searching for the above strings in the root library path
// of your compiler should enable the correct libraries to be
// identified if they aren't immediately obvious.
//
// Note that the current implementation of IASIOThiscallResolver
// is not COM compliant - it does not correctly implement the
// IUnknown interface. Implementing it is not necessary because
// it is not called by parts of the ASIO SDK which call through
// theAsioDriver ptr. The IUnknown methods are implemented as
// assert(false) to ensure that the code fails if they are
// ever called.
// Restrictions: None. Public Domain & Open Source distribute freely
// You may use IASIOThiscallResolver commercially as well as
// privately.
// You the user assume the responsibility for the use of the
// files, binary or text, and there is no guarantee or warranty,
// expressed or implied, including but not limited to the
// implied warranties of merchantability and fitness for a
// particular purpose. You assume all responsibility and agree
// to hold no entity, copyright holder or distributors liable
// for any loss of data or inaccurate representations of data
// as a result of using IASIOThiscallResolver.
// Version: 1.4 Added separate macro CALL_THISCALL_1_DOUBLE from
// Andrew Baldwin, and volatile for whole gcc asm blocks,
// both for compatibility with newer gcc versions. Cleaned up
// Borland asm to use one less register.
// 1.3 Switched to including assert.h for better compatibility.
// Wrapped entire .h and .cpp contents with a check for
// _MSC_VER to provide better compatibility with MS compilers.
// Changed Singleton implementation to use static instance
// instead of freestore allocated instance. Removed ASIOExit
// macro as it is no longer needed.
// 1.2 Removed semicolons from ASIOInit and ASIOExit macros to
// allow them to be embedded in expressions (if statements).
// Cleaned up some comments. Removed combase.c dependency (it
// doesn't compile with BCB anyway) by stubbing IUnknown.
// 1.1 Incorporated comments from Ross Bencina including things
// such as changing name from ThiscallResolver to
// IASIOThiscallResolver, tidying up the constructor, fixing
// a bug in IASIOThiscallResolver::ASIOExit() and improving
// portability through the use of conditional compilation
// 1.0 Initial working version.
// Created: 6/09/2003
// Authors: Fraser Adams
// Ross Bencina
// Rene G. Ceballos
// Martin Fay
// Antti Silvast
// Andrew Baldwin
//
// ****************************************************************************
#ifndef included_iasiothiscallresolver_h
#define included_iasiothiscallresolver_h
// We only need IASIOThiscallResolver at all if we are on Win32. For other
// platforms we simply bypass the IASIOThiscallResolver definition to allow us
// to be safely #include'd whatever the platform to keep client code portable
#if (defined(WIN32) || defined(_WIN32) || defined(__WIN32__)) && !defined(_WIN64)
// If microsoft compiler we can call IASIO directly so IASIOThiscallResolver
// is not used.
#if !defined(_MSC_VER)
// The following is in order to ensure that this header is only included after
// the other ASIO headers (except for the case of iasiothiscallresolver.cpp).
// We need to do this because IASIOThiscallResolver works by eclipsing the
// original definition of ASIOInit() with a macro (see below).
#if !defined(iasiothiscallresolver_sourcefile)
#if !defined(__ASIO_H)
#error iasiothiscallresolver.h must be included AFTER asio.h
#endif
#endif
#include <windows.h>
#include <asiodrvr.h> /* From ASIO SDK */
class IASIOThiscallResolver : public IASIO {
private:
IASIO* that_; // Points to the real IASIO
static IASIOThiscallResolver instance; // Singleton instance
// Constructors - declared private so construction is limited to
// our Singleton instance
IASIOThiscallResolver();
IASIOThiscallResolver(IASIO* that);
public:
// Methods from the IUnknown interface. We don't fully implement IUnknown
// because the ASIO SDK never calls these methods through theAsioDriver ptr.
// These methods are implemented as assert(false).
virtual HRESULT STDMETHODCALLTYPE QueryInterface(REFIID riid, void **ppv);
virtual ULONG STDMETHODCALLTYPE AddRef();
virtual ULONG STDMETHODCALLTYPE Release();
// Methods from the IASIO interface, implemented as forwarning calls to that.
virtual ASIOBool init(void *sysHandle);
virtual void getDriverName(char *name);
virtual long getDriverVersion();
virtual void getErrorMessage(char *string);
virtual ASIOError start();
virtual ASIOError stop();
virtual ASIOError getChannels(long *numInputChannels, long *numOutputChannels);
virtual ASIOError getLatencies(long *inputLatency, long *outputLatency);
virtual ASIOError getBufferSize(long *minSize, long *maxSize, long *preferredSize, long *granularity);
virtual ASIOError canSampleRate(ASIOSampleRate sampleRate);
virtual ASIOError getSampleRate(ASIOSampleRate *sampleRate);
virtual ASIOError setSampleRate(ASIOSampleRate sampleRate);
virtual ASIOError getClockSources(ASIOClockSource *clocks, long *numSources);
virtual ASIOError setClockSource(long reference);
virtual ASIOError getSamplePosition(ASIOSamples *sPos, ASIOTimeStamp *tStamp);
virtual ASIOError getChannelInfo(ASIOChannelInfo *info);
virtual ASIOError createBuffers(ASIOBufferInfo *bufferInfos, long numChannels, long bufferSize, ASIOCallbacks *callbacks);
virtual ASIOError disposeBuffers();
virtual ASIOError controlPanel();
virtual ASIOError future(long selector,void *opt);
virtual ASIOError outputReady();
// Class method, see ASIOInit() macro below.
static ASIOError ASIOInit(ASIODriverInfo *info); // Delegates to ::ASIOInit
};
// Replace calls to ASIOInit with our interposing version.
// This macro enables us to perform thiscall resolution simply by #including
// <iasiothiscallresolver.h> after the asio #includes (this file _must_ be
// included _after_ the asio #includes)
#define ASIOInit(name) IASIOThiscallResolver::ASIOInit((name))
#endif /* !defined(_MSC_VER) */
#endif /* Win32 */
#endif /* included_iasiothiscallresolver_h */
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