From af370088fc178996a46ee508aaa1a2c46318bbf2 Mon Sep 17 00:00:00 2001
From: Michael Smith <mikesmiffy128@gmail.com>
Date: Fri, 26 Dec 2025 23:12:11 +0000
Subject: Move to static trampolines and type-safe hooks

For some reason the DLL got a tiny little bit bigger again but that's
fine. This will make orig_ calls more efficient in the inline case, and
also make it harder to screw up and hook the wrong thing by mistake.

Self-explanatory-ish, apart from the fact it's a fairly large API change
of course. And it relies on some more bonkers assembler directive
hackery.

But it works!

The only complaint one might have is that the featsetup functions no
longer take an explicit string which occasionally yields slightly less
perfect error messages, but I've decided this isn't really a problem and
makes the API nicer to use. It's a tradeoff, innit.
---
 src/fastfwd.c | 33 ++++++++++++++++-----------------
 1 file changed, 16 insertions(+), 17 deletions(-)

(limited to 'src/fastfwd.c')

diff --git a/src/fastfwd.c b/src/fastfwd.c
index 78f2d47..0e6cb06 100644
--- a/src/fastfwd.c
+++ b/src/fastfwd.c
@@ -17,8 +17,6 @@
  * PERFORMANCE OF THIS SOFTWARE.
  */
 
-#include <stdlib.h>
-
 #include "chunklets/x86.h"
 #include "engineapi.h"
 #include "errmsg.h"
@@ -42,12 +40,12 @@ REQUIRE_GAMEDATA(vtidx_Frame)
 REQUIRE_GAMEDATA(vtidx_GetRealTime)
 REQUIRE_GAMEDATA(vtidx_HostFrameTime)
 
-typedef void (*Host_AccumulateTime_func)(float dt);
-static Host_AccumulateTime_func orig_Host_AccumulateTime;
 static float *realtime, *host_frametime;
-
 static float skiptime = 0.0, skiprate;
-static void hook_Host_AccumulateTime(float dt) {
+
+typedef void (*Host_AccumulateTime_func)(float dt);
+DEF_INLINE_HOOK(Host_AccumulateTime_func, Host_AccumulateTime)
+static void hookdest_Host_AccumulateTime(float dt) {
 	float skipinc = skiprate * dt;
 	if_hot (!skiptime) {
 		orig_Host_AccumulateTime(dt);
@@ -127,7 +125,8 @@ static inline void *find_FrameUpdate(void *HostState_Frame) {
 	return 0;
 }
 
-static inline bool find_Host_AccumulateTime(void *_Host_RunFrame) {
+static inline Host_AccumulateTime_func find_Host_AccumulateTime(
+		void *_Host_RunFrame) {
 #ifdef _WIN32
 	const uchar *insns = (const uchar *)_Host_RunFrame;
 	for (const uchar *p = insns; p - insns < 384;) {
@@ -135,17 +134,16 @@ static inline bool find_Host_AccumulateTime(void *_Host_RunFrame) {
 			NEXT_INSN(p, "Host_AccumulateTime");
 			while (p - insns < 384) {
 				if (p[0] == X86_CALL) {
-					orig_Host_AccumulateTime = (Host_AccumulateTime_func)(
+					return (Host_AccumulateTime_func)(
 							p + 5 + mem_loads32(p + 1));
-					return true;
 				}
 				NEXT_INSN(p, "Host_AccumulateTime");
 			}
-			return false;
+			return 0;
 		}
 		NEXT_INSN(p, "Host_AccumulateTime");
 	}
-	return false;
+	return 0;
 #else
 #warning TODO(linux): yet another assembly thing
 #endif
@@ -232,21 +230,22 @@ INIT {
 		errmsg_errorx("couldn't find _Host_RunFrame function");
 		return FEAT_INCOMPAT;
 	}
-	if_cold (!find_Host_AccumulateTime(func)) {
+	Host_AccumulateTime_func Host_AccumulateTime =
+			find_Host_AccumulateTime(func);
+	if_cold (!Host_AccumulateTime) {
 		errmsg_errorx("couldn't find Host_AccumulateTime function");
 		return FEAT_INCOMPAT;
 	}
-	struct hook_inline_featsetup_ret h = hook_inline_featsetup(
-			(void *)orig_Host_AccumulateTime, (void **)&orig_Host_AccumulateTime,
-			"Host_AccumulateTime");
+	struct hook_featsetup_ret_Host_AccumulateTime h =
+			hook_featsetup_Host_AccumulateTime(Host_AccumulateTime);
 	if_cold (h.err) return h.err;
-	hook_inline_commit(h.prologue, (void *)&hook_Host_AccumulateTime);
+	hook_commit_Host_AccumulateTime(h.hookpos, &hookdest_Host_AccumulateTime);
 	return FEAT_OK;
 }
 
 END {
 	if_hot (!sst_userunloaded) return;
-	unhook_inline((void *)orig_Host_AccumulateTime);
+	unhook_Host_AccumulateTime();
 }
 
 // vi: sw=4 ts=4 noet tw=80 cc=80
-- 
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