/**

  * vim: set ts=4 :

  * =============================================================================

  * SourceMod SDKTools Extension

  * Copyright (C) 2004-2008 AlliedModders LLC.  All rights reserved.

  * =============================================================================

  *

  * This program is free software; you can redistribute it and/or modify it under

  * the terms of the GNU General Public License, version 3.0, as published by the

  * Free Software Foundation.

  * 

  * This program is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

  * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more

  * details.

  *

  * You should have received a copy of the GNU General Public License along with

  * this program.  If not, see <http://www.gnu.org/licenses/>.

  *

  * As a special exception, AlliedModders LLC gives you permission to link the

  * code of this program (as well as its derivative works) to "Half-Life 2," the

  * "Source Engine," the "SourcePawn JIT," and any Game MODs that run on software

  * by the Valve Corporation.  You must obey the GNU General Public License in

  * all respects for all other code used.  Additionally, AlliedModders LLC grants

  * this exception to all derivative works.  AlliedModders LLC defines further

  * exceptions, found in LICENSE.txt (as of this writing, version JULY-31-2007),

  * or <http://www.sourcemod.net/license.php>.

  *

  * Version: $Id$

  */

 #include "extension.h"

 void **g_pGameRules = NULL;

 void *g_EntList = NULL;

 void InitializeValveGlobals()

 {

 	g_EntList = gamehelpers->GetGlobalEntityList();

 	/*

 	 * g_pGameRules

 	 *

 	 * First try to lookup pointer directly for platforms with symbols.

 	 * If symbols aren't present (Windows or stripped Linux/Mac), 

 	 * attempt find via CreateGameRulesObject + offset

 	 */

 	char *addr;

 	if (g_pGameConf->GetMemSig("g_pGameRules", (void **)&addr) && addr)

 	{

 		g_pGameRules = reinterpret_cast<void **>(addr);

 	}

 	else if (g_pGameConf->GetMemSig("CreateGameRulesObject", (void **)&addr) && addr)

 	{

 		int offset;

 		if (!g_pGameConf->GetOffset("g_pGameRules", &offset) || !offset)

 		{

 			return;

 		}

 		g_pGameRules = *reinterpret_cast<void ***>(addr + offset);

 	}

 }

 size_t UTIL_StringToSignature(const char *str, char buffer[], size_t maxlength)

 {

 	size_t real_bytes = 0;

 	size_t length = strlen(str);

 	for (size_t i=0; i<length; i++)

 	{

 		if (real_bytes >= maxlength)

 		{

 			break;

 		}

 		buffer[real_bytes++] = (unsigned char)str[i];

 		if (str[i] == '\\'

 			&& str[i+1] == 'x')

 		{

 			if (i + 3 >= length)

 			{

 				continue;

 			}

 			/* Get the hex part */

 			char s_byte[3];

 			int r_byte;

 			s_byte[0] = str[i+2];

 			s_byte[1] = str[i+3];

 			s_byte[2] = '\n';

 			/* Read it as an integer */

 			sscanf(s_byte, "%x", &r_byte);

 			/* Save the value */

 			buffer[real_bytes-1] = (unsigned char)r_byte;

 			/* Adjust index */

 			i += 3;

 		}

 	}

 	return real_bytes;

 }

 bool UTIL_VerifySignature(const void *addr, const char *sig, size_t len)

 {

 	unsigned char *addr1 = (unsigned char *) addr;

 	unsigned char *addr2 = (unsigned char *) sig;

 	for (size_t i = 0; i < len; i++)

 	{

 		if (addr2[i] == '*')

 			continue;

 		if (addr1[i] != addr2[i])

 			return false;

 	}

 	return true;

 }

 #if defined PLATFORM_WINDOWS

 void GetIServer()

 {

 	const char *sigstr;

 	char sig[32];

 	size_t siglen;

 	int offset;

 	void *vfunc = NULL;

 #if defined METAMOD_PLAPI_VERSION || PLAPI_VERSION >= 11

 	/* Get the CreateFakeClient function pointer */

 	if (!(vfunc=SH_GET_ORIG_VFNPTR_ENTRY(engine, &IVEngineServer::CreateFakeClient)))

 	{

 		return;

 	}

 #else

 	/* Get the interface manually */

 	SourceHook::MemFuncInfo info = {true, -1, 0, 0};

 	SourceHook::GetFuncInfo(&IVEngineServer::CreateFakeClient, info);

 	vfunc = enginePatch->GetOrigFunc(info.vtbloffs, info.vtblindex);

 	if (!vfunc)

 	{

 		void **vtable = *reinterpret_cast<void ***>(enginePatch->GetThisPtr() + info.thisptroffs + info.vtbloffs);

 		vfunc = vtable[info.vtblindex];

 	}

 #endif

 	/* Get signature string for IVEngineServer::CreateFakeClient() */

 	sigstr = g_pGameConf->GetKeyValue("CreateFakeClient_Windows");

 	if (!sigstr)

 	{

 		return;

 	}

 	/* Convert signature string to signature bytes */

 	siglen = UTIL_StringToSignature(sigstr, sig, sizeof(sig));

 	/* Check if we're on the expected function */

 	if (!UTIL_VerifySignature(vfunc, sig, siglen))

 	{

 		return;

 	}

 	/* Get the offset into CreateFakeClient */

 	if (!g_pGameConf->GetOffset("sv", &offset))

 	{

 		return;

 	}

 	/* Finally we have the interface we were looking for */

 	iserver = *reinterpret_cast<IServer **>(reinterpret_cast<unsigned char *>(vfunc) + offset);

 }

 #elif defined PLATFORM_POSIX

 void GetIServer()

 {

 	void *addr;

 	if (!g_pGameConf->GetMemSig("sv", &addr) || !addr)

 	{

 		return;

 	}

 	iserver = reinterpret_cast<IServer *>(addr);

 }

 #endif