/*-------------------------------------------------------------------------
 * drawElements Utility Library
 * ----------------------------
 *
 * Copyright 2014 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 *//*!
 * \file
 * \brief Dynamic link library abstraction.
 *//*--------------------------------------------------------------------*/

#include "deDynamicLibrary.h"
#include "deMemory.h"

#if (DE_OS == DE_OS_UNIX) || (DE_OS == DE_OS_ANDROID) || (DE_OS == DE_OS_OSX) || (DE_OS == DE_OS_SYMBIAN) || (DE_OS == DE_OS_IOS)
/* Posix implementation. */

#include <dlfcn.h>

struct deDynamicLibrary_s
{
	void*	libHandle;
};

deDynamicLibrary* deDynamicLibrary_open (const char* fileName)
{
	deDynamicLibrary* library = (deDynamicLibrary*)deCalloc(sizeof(deDynamicLibrary));
	if (!library)
		return DE_NULL;
	
	library->libHandle = dlopen(fileName, RTLD_LAZY);
	if (!library->libHandle)
	{
		deFree(library);
		return DE_NULL;
	}
	
	return library;
}

void deDynamicLibrary_close (deDynamicLibrary* library)
{
	if (library && library->libHandle)
		dlclose(library->libHandle);
	deFree(library);
}

deFunctionPtr deDynamicLibrary_getFunction (const deDynamicLibrary* library, const char* symbolName)
{
	/* C forbids direct cast from object pointer to function pointer */
	union
	{
		deFunctionPtr	funcPtr;
		void*			objPtr;
	} ptr;

	DE_ASSERT(library && library->libHandle && symbolName);
	ptr.objPtr = dlsym(library->libHandle, symbolName);
	return ptr.funcPtr;
}

#elif (DE_OS == DE_OS_WIN32)
/* Win32 implementation. */

#define WIN32_LEAN_AND_MEAN
#define VC_EXTRALEAN
#include <windows.h>

struct deDynamicLibrary_s
{
	HINSTANCE	handle;
};

deDynamicLibrary* deDynamicLibrary_open (const char* fileName)
{
	deDynamicLibrary* library = (deDynamicLibrary*)deCalloc(sizeof(deDynamicLibrary));
	if (!library)
		return DE_NULL;
	
	library->handle = LoadLibrary(fileName);
	if (!library->handle)
	{
		deFree(library);
		return DE_NULL;
	}
	
	return library;
}

void deDynamicLibrary_close (deDynamicLibrary* library)
{
	if (library && library->handle)
		FreeLibrary(library->handle);
	deFree(library);
}

deFunctionPtr deDynamicLibrary_getFunction (const deDynamicLibrary* library, const char* symbolName)
{
	DE_ASSERT(library && library->handle && symbolName);
	return (deFunctionPtr)GetProcAddress(library->handle, symbolName);
}

#else
#	error deDynamicLibrary is not implemented on this OS
#endif