From 46850a353b23207c085509dd91905f73295c8933 Mon Sep 17 00:00:00 2001
From: NovaRain <novarain@gmail.com>
Date: Sun, 20 Jan 2019 22:13:30 +0800
Subject: [PATCH] Corrected code in FileSystem.cpp (from Mr.Stalin)

Added fix for db_freadInt_ engine function from BugFixes.cpp when enabling UseFileSystemOverride.
---
 sfall/Modules/BugFixes.cpp     |  4 +--
 sfall/Modules/FileSystem.cpp   | 50 +++++++++++++++++++++++++---------
 sfall/Modules/FileSystem.h     |  2 +-
 sfall/Modules/LoadGameHook.cpp |  2 +-
 4 files changed, 41 insertions(+), 17 deletions(-)

diff --git a/sfall/Modules/BugFixes.cpp b/sfall/Modules/BugFixes.cpp
index a2d79870..3594ee24 100644
--- a/sfall/Modules/BugFixes.cpp
+++ b/sfall/Modules/BugFixes.cpp
@@ -2200,8 +2200,8 @@ void BugFixes::init()
 	// number of values (for chem_primary_desire)
 	MakeJump(0x42C12C, config_get_values_hack);
 
-	// Fix returned result value
-	HookCall(0x4C6162, db_freadInt_hook); // TODO: Resolve conflict in FileSystem.cpp
+	// Fix returned result value when the file is missing
+	HookCall(0x4C6162, db_freadInt_hook);
 }
 
 }
diff --git a/sfall/Modules/FileSystem.cpp b/sfall/Modules/FileSystem.cpp
index 7a2d9b90..60f43ac0 100644
--- a/sfall/Modules/FileSystem.cpp
+++ b/sfall/Modules/FileSystem.cpp
@@ -57,19 +57,22 @@ std::vector<fsFile> files;
 static DWORD loadedFiles = 0; // used for internal sfall data
 bool FileSystem::UsingFileSystem = false;
 
-static void _stdcall xfclose(sFile* file) {
+static long _stdcall xfclose(sFile* file) {
 	delete file->opnFile;
 	delete file;
+	return 0;
 }
 
 static void __declspec(naked) asm_xfclose(sFile* file) {
 	__asm {
 		cmp  [eax], 3; // byte
 		jnz  end;
-		pushadc;
+		push edx;
+		push ecx;
 		push eax;
 		call xfclose;
-		popadc;
+		pop  ecx;
+		pop  edx;
 		retn;
 end:
 		jmp  fo::funcoffs::xfclose_;
@@ -259,6 +262,25 @@ end:
 	}
 }
 
+static __declspec(naked) int asm_xfread_fix(void* buf, int elsize, int count, sFile* file) {
+	__asm {
+		cmp  [ecx], 3;
+		jnz  end;
+		push ebx;    // count
+		push eax;    // buf
+		call xfread; // ecx - file, edx - elsize
+		retn;
+end:
+		call fo::funcoffs::xfread_;
+		// fix
+		test eax, eax;
+		jnz  skip;
+		dec  eax;
+skip:
+		retn;
+	}
+}
+
 static int __fastcall xfwrite(sFile* file, int elsize, const void* buf, int count) {
 	return 0;
 }
@@ -388,7 +410,7 @@ end:
 	}
 }
 
-void FileSystemReset() {
+static void FileSystemReset() {
 	if (files.empty()) return;
 	for (DWORD i = loadedFiles; i < files.size(); i++) {
 		if (files[i].data) delete[] files[i].data;
@@ -415,7 +437,6 @@ void FileSystem::Save(HANDLE h) {
 }
 
 static void FileSystemLoad() {
-	FileSystemReset();
 	char buf[MAX_PATH];
 	GetSavePath(buf, "fs");
 
@@ -448,11 +469,7 @@ static void __declspec(naked) FSLoadHook() {
 	}
 }
 
-void FileSystemInit() {
-	FileSystem::UsingFileSystem = true;
-
-	MakeJump(0x47CCE2, FSLoadHook);
-
+static void FileSystemOverride() {
 	HookCalls(asm_xfclose, {0x4C5DBD, 0x4C5EA5, 0x4C5EB4});
 	HookCalls(asm_xfopen, {0x4C5DA9, 0x4C5E16, 0x4C5EC8});
 
@@ -466,7 +483,7 @@ void FileSystemInit() {
 	HookCall(0x4C5FF4, asm_xfungetc);
 
 	HookCalls(asm_xfread, {0x4C5E5C, 0x4C5E8A, 0x4C5E9E, 0x4C603D, 0x4C6076, 0x4C60AA});
-	HookCall(0x4C6162, asm_xfread); // for fix
+	HookCall(0x4C6162, asm_xfread_fix); // with bug fix from BugFixes.cpp
 
 	HookCall(0x4C60B8, asm_xfwrite);
 	HookCall(0x4C60C0, asm_xfseek);
@@ -477,7 +494,7 @@ void FileSystemInit() {
 	HookCalls(asm_xfilelength, {0x4C5DB4, 0x4C5E2D, 0x4C68BC});
 }
 
-DWORD NewFile(fsFile &file, const char* path, int size) {
+static DWORD NewFile(fsFile &file, const char* path, int size) {
 	strcpy_s(file.name, path);
 	file.length = size;
 	file.wpos = 0;
@@ -679,10 +696,17 @@ void _stdcall FSresize(DWORD id, DWORD size) {
 	delete[] buf;
 }
 
+bool FileSystem::IsEmpty() {
+	return (int)(files.size() - loadedFiles) <= 0;
+}
+
 void FileSystem::init() {
 	if (GetConfigInt("Misc", "UseFileSystemOverride", 0)) {
-		FileSystemInit();
+		FileSystemOverride();
+		UsingFileSystem = true;
 	}
+	MakeJump(0x47CCE2, FSLoadHook); // LoadGame_
+
 	LoadGameHook::OnGameReset() += FileSystemReset;
 }
 
diff --git a/sfall/Modules/FileSystem.h b/sfall/Modules/FileSystem.h
index 5e933861..83c47826 100644
--- a/sfall/Modules/FileSystem.h
+++ b/sfall/Modules/FileSystem.h
@@ -31,6 +31,7 @@ public:
 	static bool UsingFileSystem;
 	// save FileSystem data to a save game file
 	static void Save(HANDLE h);
+	static bool IsEmpty();
 };
 
 DWORD _stdcall FScreate(const char* path, int size);
@@ -40,7 +41,6 @@ DWORD _stdcall FSfind(const char* path);
 void _stdcall FSwrite_byte(DWORD id, int data);
 void _stdcall FSwrite_short(DWORD id, int data);
 void _stdcall FSwrite_int(DWORD id, int data);
-//void _stdcall fs_write_float(DWORD id, int data);
 void _stdcall FSwrite_string(DWORD id, const char* data);
 void _stdcall FSwrite_bstring(DWORD id, const char* data);
 int _stdcall FSread_byte(DWORD id);
diff --git a/sfall/Modules/LoadGameHook.cpp b/sfall/Modules/LoadGameHook.cpp
index 522fa6fb..a46f8caf 100644
--- a/sfall/Modules/LoadGameHook.cpp
+++ b/sfall/Modules/LoadGameHook.cpp
@@ -142,7 +142,7 @@ static void _stdcall SaveGame2() {
 		CloseHandle(h);
 	}
 
-	if (!FileSystem::UsingFileSystem) return;
+	if (FileSystem::IsEmpty()) return;
 	GetSavePath(buf, "fs");
 	h = CreateFileA(buf, GENERIC_WRITE, 0, 0, CREATE_ALWAYS, 0, 0);
 	if (h != INVALID_HANDLE_VALUE) {