Add `FUNCTION_AT` and `VAR_AT` macros (#416)

* add FUNCTION_AT and VAR_AT macros

* fix build issues oops

* fix formatting

* add PREDEFINED_VAR_AT

* change func name

* fixup formatting

* update to use DEFINED_VAR_AT

7 files changed, 105 insertions, 53 deletions

diff --git a/NorthstarDLL/core/convar/concommand.cpp b/NorthstarDLL/core/convar/concommand.cpp
index 88bd8825..67c867f8 100644
--- a/NorthstarDLL/core/convar/concommand.cpp
+++ b/NorthstarDLL/core/convar/concommand.cpp
@@ -4,8 +4,6 @@
 
 #include <iostream>
 
-bool (*CCommand__Tokenize)(CCommand& self, const char* pCommandString, R2::cmd_source_t commandSource);
-
 //-----------------------------------------------------------------------------
 // Purpose: Returns true if this is a command
 // Output : bool
diff --git a/NorthstarDLL/core/hooks.cpp b/NorthstarDLL/core/hooks.cpp
index 34b48d1d..7c70b0a5 100644
--- a/NorthstarDLL/core/hooks.cpp
+++ b/NorthstarDLL/core/hooks.cpp
@@ -65,6 +65,9 @@ __dllLoadCallback::__dllLoadCallback(
 
 void __fileAutohook::Dispatch()
 {
+	for (__autovar* var : vars)
+		var->Dispatch();
+
 	for (__autohook* hook : hooks)
 		hook->Dispatch();
 }
@@ -114,6 +117,42 @@ bool ManualHook::Dispatch(LPVOID addr, LPVOID* orig)
 	return false;
 }
 
+uintptr_t ParseDLLOffsetString(const char* pAddrString)
+{
+	// in the format server.dll + 0xDEADBEEF
+	int iDllNameEnd = 0;
+	for (; !isspace(pAddrString[iDllNameEnd]) && pAddrString[iDllNameEnd] != '+'; iDllNameEnd++)
+		;
+
+	char* pModuleName = new char[iDllNameEnd + 1];
+	memcpy(pModuleName, pAddrString, iDllNameEnd);
+	pModuleName[iDllNameEnd] = '\0';
+
+	// get the module address
+	const HMODULE pModuleAddr = GetModuleHandleA(pModuleName);
+
+	if (!pModuleAddr)
+		return 0;
+
+	// get the offset string
+	uintptr_t iOffset = 0;
+
+	int iOffsetBegin = iDllNameEnd;
+	int iOffsetEnd = strlen(pAddrString);
+
+	// seek until we hit the start of the number offset
+	for (; !(pAddrString[iOffsetBegin] >= '0' && pAddrString[iOffsetBegin] <= '9') && pAddrString[iOffsetBegin]; iOffsetBegin++)
+		;
+
+	bool bIsHex = pAddrString[iOffsetBegin] == '0' && (pAddrString[iOffsetBegin + 1] == 'X' || pAddrString[iOffsetBegin + 1] == 'x');
+	if (bIsHex)
+		iOffset = std::stoi(pAddrString + iOffsetBegin + 2, 0, 16);
+	else
+		iOffset = std::stoi(pAddrString + iOffsetBegin);
+
+	return ((uintptr_t)pModuleAddr + iOffset);
+}
+
 // dll load callback stuff
 // this allows for code to register callbacks to be run as soon as a dll is loaded, mainly to allow for patches to be made on dll load
 struct DllLoadCallback
diff --git a/NorthstarDLL/core/hooks.h b/NorthstarDLL/core/hooks.h
index f47791fb..0144712f 100644
--- a/NorthstarDLL/core/hooks.h
+++ b/NorthstarDLL/core/hooks.h
@@ -63,16 +63,20 @@ class __dllLoadCallback
 
 // new macro hook stuff
 class __autohook;
+class __autovar;
 
 class __fileAutohook
 {
   public:
 	std::vector<__autohook*> hooks;
+	std::vector<__autovar*> vars;
 
 	void Dispatch();
 	void DispatchForModule(const char* pModuleName);
 };
 
+uintptr_t ParseDLLOffsetString(const char* pAddrString);
+
 // initialise autohooks for this file
 #define AUTOHOOK_INIT()                                                                                                                    \
 	namespace                                                                                                                              \
@@ -187,39 +191,7 @@ class __autohook
 
 		case OFFSET_STRING:
 		{
-			// in the format server.dll + 0xDEADBEEF
-			int iDllNameEnd = 0;
-			for (; !isspace(pAddrString[iDllNameEnd]) && pAddrString[iDllNameEnd] != '+'; iDllNameEnd++)
-				;
-
-			char* pModuleName = new char[iDllNameEnd + 1];
-			memcpy(pModuleName, pAddrString, iDllNameEnd);
-			pModuleName[iDllNameEnd] = '\0';
-
-			// get the module address
-			const HMODULE pModuleAddr = GetModuleHandleA(pModuleName);
-
-			if (!pModuleAddr)
-				break;
-
-			// get the offset string
-			uintptr_t iOffset = 0;
-
-			int iOffsetBegin = iDllNameEnd;
-			int iOffsetEnd = strlen(pAddrString);
-
-			// seek until we hit the start of the number offset
-			for (; !(pAddrString[iOffsetBegin] >= '0' && pAddrString[iOffsetBegin] <= '9') && pAddrString[iOffsetBegin]; iOffsetBegin++)
-				;
-
-			bool bIsHex =
-				pAddrString[iOffsetBegin] == '0' && (pAddrString[iOffsetBegin + 1] == 'X' || pAddrString[iOffsetBegin + 1] == 'x');
-			if (bIsHex)
-				iOffset = std::stoi(pAddrString + iOffsetBegin + 2, 0, 16);
-			else
-				iOffset = std::stoi(pAddrString + iOffsetBegin);
-
-			targetAddr = (LPVOID)((uintptr_t)pModuleAddr + iOffset);
+			targetAddr = (LPVOID)ParseDLLOffsetString(pAddrString);
 			break;
 		}
 
@@ -309,3 +281,51 @@ class ManualHook
 
 void MakeHook(LPVOID pTarget, LPVOID pDetour, void* ppOriginal, const char* pFuncName = "");
 #define MAKEHOOK(pTarget, pDetour, ppOriginal) MakeHook(pTarget, pDetour, ppOriginal, __STR(pDetour))
+
+class __autovar
+{
+  public:
+	char* m_pAddrString;
+	void** m_pTarget;
+
+  public:
+	__autovar(__fileAutohook* pAutohook, const char* pAddrString, void** pTarget)
+	{
+		m_pTarget = pTarget;
+
+		const int iAddrStrlen = strlen(pAddrString) + 1;
+		m_pAddrString = new char[iAddrStrlen];
+		memcpy(m_pAddrString, pAddrString, iAddrStrlen);
+
+		pAutohook->vars.push_back(this);
+	}
+
+	void Dispatch()
+	{
+		*m_pTarget = (void*)ParseDLLOffsetString(m_pAddrString);
+	}
+};
+
+// VAR_AT(engine.dll+0x404, ConVar*, Cvar_host_timescale)
+#define VAR_AT(addrString, type, name)                                                                                                     \
+	type name;                                                                                                                             \
+	namespace                                                                                                                              \
+	{                                                                                                                                      \
+		__autovar CONCAT2(__autovar, __LINE__)(&__FILEAUTOHOOK, __STR(addrString), (void**)&name);                                         \
+	}
+
+// FUNCTION_AT(engine.dll + 0xDEADBEEF, void, __fastcall, SomeFunc, (void* a1))
+#define FUNCTION_AT(addrString, type, callingConvention, name, args)                                                                       \
+	type(*callingConvention name) args;                                                                                                    \
+	namespace                                                                                                                              \
+	{                                                                                                                                      \
+		__autovar CONCAT2(__autovar, __LINE__)(&__FILEAUTOHOOK, __STR(addrString), (void**)&name);                                         \
+	}
+
+// int* g_pSomeInt;
+// DEFINED_VAR_AT(engine.dll + 0x5005, g_pSomeInt)
+#define DEFINED_VAR_AT(addrString, name)                                                                                                   \
+	namespace                                                                                                                              \
+	{                                                                                                                                      \
+		__autovar CONCAT2(__autovar, __LINE__)(&__FILEAUTOHOOK, __STR(addrString), (void**)&name);                                         \
+	}
diff --git a/NorthstarDLL/engine/host.cpp b/NorthstarDLL/engine/host.cpp
index 436a169d..49cc3663 100644
--- a/NorthstarDLL/engine/host.cpp
+++ b/NorthstarDLL/engine/host.cpp
@@ -5,7 +5,9 @@
 #include "shared/misccommands.h"
 #include "r2engine.h"
 #include "core/tier0.h"
+
 AUTOHOOK_INIT()
+
 // clang-format off
 AUTOHOOK(Host_Init, engine.dll + 0x155EA0,
 void, __fastcall, (bool bDedicated))
@@ -24,6 +26,7 @@ void, __fastcall, (bool bDedicated))
 	else
 		R2::Cbuf_AddText(R2::Cbuf_GetCurrentPlayer(), "exec autoexec_ns_client", R2::cmd_source_t::kCommandSrcCode);
 }
+
 ON_DLL_LOAD("engine.dll", Host_Init, (CModule module))
 {
 	AUTOHOOK_DISPATCH()
diff --git a/NorthstarDLL/engine/hoststate.cpp b/NorthstarDLL/engine/hoststate.cpp
index 5a295425..44a66113 100644
--- a/NorthstarDLL/engine/hoststate.cpp
+++ b/NorthstarDLL/engine/hoststate.cpp
@@ -18,10 +18,10 @@ namespace R2
 	CHostState* g_pHostState;
 } // namespace R2
 
-ConVar* Cvar_hostport;
 std::string sLastMode;
 
-void (*_fastcall _Cmd_Exec_f)(const CCommand& arg, bool bOnlyIfExists, bool bUseWhitelists);
+VAR_AT(engine.dll + 0x13FA6070, ConVar*, Cvar_hostport);
+FUNCTION_AT(engine.dll + 0x1232C0, void, __fastcall, _Cmd_Exec_f, (const CCommand& arg, bool bOnlyIfExists, bool bUseWhitelists));
 
 void ServerStartingOrChangingMap()
 {
@@ -194,7 +194,4 @@ ON_DLL_LOAD_RELIESON("engine.dll", HostState, ConVar, (CModule module))
 	AUTOHOOK_DISPATCH()
 
 	g_pHostState = module.Offset(0x7CF180).As<CHostState*>();
-	Cvar_hostport = module.Offset(0x13FA6070).As<ConVar*>();
-
-	_Cmd_Exec_f = module.Offset(0x1232C0).As<void (*__fastcall)(const CCommand&, bool, bool)>();
 }
diff --git a/NorthstarDLL/shared/playlist.cpp b/NorthstarDLL/shared/playlist.cpp
index 018b2a9b..ab7aab22 100644
--- a/NorthstarDLL/shared/playlist.cpp
+++ b/NorthstarDLL/shared/playlist.cpp
@@ -11,10 +11,10 @@ AUTOHOOK_INIT()
 // use the R2 namespace for game funcs
 namespace R2
 {
-	const char* (*GetCurrentPlaylistName)();
-	void (*SetCurrentPlaylist)(const char* pPlaylistName);
-	void (*SetPlaylistVarOverride)(const char* pVarName, const char* pValue);
-	const char* (*GetCurrentPlaylistVar)(const char* pVarName, bool bUseOverrides);
+	DEFINED_VAR_AT(engine.dll + 0x18C640, GetCurrentPlaylistName);
+	DEFINED_VAR_AT(engine.dll + 0x18EB20, SetCurrentPlaylist);
+	DEFINED_VAR_AT(engine.dll + 0x18ED00, SetPlaylistVarOverride);
+	DEFINED_VAR_AT(engine.dll + 0x18C680, GetCurrentPlaylistVar);
 } // namespace R2
 
 ConVar* Cvar_ns_use_clc_SetPlaylistVarOverride;
@@ -104,11 +104,6 @@ ON_DLL_LOAD_RELIESON("engine.dll", PlaylistHooks, (ConCommand, ConVar), (CModule
 {
 	AUTOHOOK_DISPATCH()
 
-	R2::GetCurrentPlaylistName = module.Offset(0x18C640).As<const char* (*)()>();
-	R2::SetCurrentPlaylist = module.Offset(0x18EB20).As<void (*)(const char*)>();
-	R2::SetPlaylistVarOverride = module.Offset(0x18ED00).As<void (*)(const char*, const char*)>();
-	R2::GetCurrentPlaylistVar = module.Offset(0x18C680).As<const char* (*)(const char*, bool)>();
-
 	// playlist is the name of the command on respawn servers, but we already use setplaylist so can't get rid of it
 	RegisterConCommand("playlist", ConCommand_playlist, "Sets the current playlist", FCVAR_NONE);
 	RegisterConCommand("setplaylist", ConCommand_playlist, "Sets the current playlist", FCVAR_NONE);
diff --git a/NorthstarDLL/shared/playlist.h b/NorthstarDLL/shared/playlist.h
index c77b37d9..e56fdf96 100644
--- a/NorthstarDLL/shared/playlist.h
+++ b/NorthstarDLL/shared/playlist.h
@@ -3,8 +3,8 @@
 // use the R2 namespace for game funcs
 namespace R2
 {
-	extern const char* (*GetCurrentPlaylistName)();
-	extern void (*SetCurrentPlaylist)(const char* pPlaylistName);
-	extern void (*SetPlaylistVarOverride)(const char* pVarName, const char* pValue);
-	extern const char* (*GetCurrentPlaylistVar)(const char* pVarName, bool bUseOverrides);
+	inline const char* (*GetCurrentPlaylistName)();
+	inline void (*SetCurrentPlaylist)(const char* pPlaylistName);
+	inline void (*SetPlaylistVarOverride)(const char* pVarName, const char* pValue);
+	inline const char* (*GetCurrentPlaylistVar)(const char* pVarName, bool bUseOverrides);
 } // namespace R2