// Copyright (c) 2006-2009 Nokia Corporation and/or its subsidiary(-ies).

// All rights reserved.

// This component and the accompanying materials are made available

// under the terms of "Eclipse Public License v1.0"

// which accompanies this distribution, and is available

// at the URL "http://www.eclipse.org/legal/epl-v10.html".

//

// Initial Contributors:

// Nokia Corporation - initial contribution.

//

// Contributors:

//

// Description:

// For the Winscw Emulator only, selects between REF, GCE and non-GCE version of EGL.

// Notes:

//   The default is the non-GCE based version.

//   To use the REF version GCE needs to be enabled. 

//

// To select the GCE version do one of:

// 1. Add a line to the epoc.ini file in \epoc32\data like this:

// symbian_graphics_use_gce ON

// or

// 2. Start epoc.exe with these parameters, (the "--" IS necessary):

// -Dsymbian_graphics_use_gce=ON --

// or

// 3. epoc.exe can be told to switch to a different initialisation file than epoc.ini, with the -M parameter.

// Progress chaining to the real libEGL is logged in epocwind.out.

// 

// To select the REF version do one of the steps above, adding 

// symbian_graphics_use_egl_ref in addition to symbian_graphics_use_gce. 

//

//

#include <emulator.h>

#include <e32svr.h>

#include <u32hal.h>

extern "C" {

#include "egl_stubs.h"

FARPROC vector[MAX_ORDINAL+1];		// 1 additional entry: vector[0] to set the initialised state

void Stop(char* aErrorMessage)

	{

	int err = GetLastError();

	RDebug::Printf("%S, (last error = %i)", aErrorMessage, err);

	_asm int 3;

	}

void fill_vector(HINSTANCE aDll)

	{

	FARPROC address = NULL;

	for (int i=1;i<=MAX_ORDINAL;i++)

		{

		address = GetProcAddress(aDll, (LPCSTR)i);

		if (address == NULL)

			{

			Stop("... has too few exported functions");

			}

		vector[i] = address;

		}

	// There's an additional _E32Dll entry point after last ordinal position.

	// Read it, but no need to store it

	address = GetProcAddress(aDll, (LPCSTR)(MAX_ORDINAL+1));

	if (address == NULL)

		{

		Stop("... has too few exported functions");

		}

	// next position should be empty

	address = GetProcAddress(aDll, (LPCSTR)(MAX_ORDINAL+2));

	if (address != NULL)

		{

		Stop("... has too many exported functions");

		}

	// Set initialised

	vector[0] = (FARPROC)1;	

	}

// redirects DLL calls to GCE or non-GCE implementation

void init_vector()

	{

	// ask HAL which configuration to use

	TBool gce = EFalse;

	UserSvr::HalFunction(EHalGroupEmulator, EEmulatorHalBoolProperty,  (TAny*)"symbian_graphics_use_gce",  &gce);

    const char* library = "";

    if (gce)

        {

		// reference EGL is for NGA only

		TBool ref = EFalse;

        UserSvr::HalFunction(EHalGroupEmulator, EEmulatorHalBoolProperty,  (TAny*)"symbian_graphics_use_egl_ref",  &ref);

        library = ref ? "libegl_ref.dll" : "libegl_gce.dll";

        }

	else

		{

		library = "libegl_nongce.dll";

		}

	RDebug::Printf("Redirecting libEGL.dll to \"%s\" ...\n", library);

	Emulator::Escape();		// prevent deadlock between EKA2 scheduler and MS kernel

	// try to load selected DLL

	HINSTANCE instance = LoadLibraryA(library);

	Emulator::Reenter();

	if (instance == NULL)

		{

		Stop("... unable to load");

		}

	else

		{

		fill_vector(instance);

		RDebug::Printf("... DLL loaded successfully");

		}

	}

__declspec(naked) void common_dispatch()

	{

	_asm cmp	dword ptr vector,0		// initialised?

	_asm je  	do_init_vector

call_though_vector:

	_asm jmp	[vector+eax*4]

do_init_vector:

	_asm push	eax

	_asm push	ecx

	_asm push	edx

	_asm call	init_vector

	_asm pop	edx

	_asm pop 	ecx

	_asm pop 	eax

	_asm jmp	call_though_vector

	}

}