From 7cba9cab9e76a7351b9ef299faa1cf611820af19 Mon Sep 17 00:00:00 2001
From: dosse91 <info@fdossena.com>
Date: Tue, 24 Nov 2020 20:56:58 +0100
Subject: [PATCH] New, simpler, pattern finding code

---
 ME2KasumiCrashFix/main.cpp | 78 ++++++++++++++------------------------
 README.md                  |  4 +-
 2 files changed, 29 insertions(+), 53 deletions(-)

diff --git a/ME2KasumiCrashFix/main.cpp b/ME2KasumiCrashFix/main.cpp
index 025630b..232b090 100644
--- a/ME2KasumiCrashFix/main.cpp
+++ b/ME2KasumiCrashFix/main.cpp
@@ -1,69 +1,47 @@
 #include <windows.h>
 #include <winuser.h>
 
-#define	patternLength 32
+#define	PATTERN_LENGTH 32
 BYTE	pattern[] = {0x83,0x3D,0xAC,0xA2,0x26,0x01,0x00,0x56,0x74,0x76,0xA1,0xBC,0xA7,0x26,0x01,0x83,0x78,0x54,0x00,0x74,0x6B,0x8B,0x40,0x54,0x83,0x78,0x40,0x00,0x74,0x62,0x8B,0x40};
 
-bool DataCompare(const BYTE* OpCodes, const BYTE* Mask, const char* StrMask)
-{
-	while (*StrMask)
-	{
-		if (*StrMask == 'x' && *OpCodes != *Mask)
-			return false;
-		++StrMask;
-		++OpCodes;
-		++Mask;
-	}
-	return true;
-}
-
-DWORD FindPattern(DWORD StartAddress, DWORD CodeLen, BYTE* Mask, char* StrMask, unsigned short ignore)
-{
-	unsigned short Ign = 0;
-	DWORD i = 0;
-	while (Ign <= ignore)
-	{
-		if (DataCompare((BYTE*)(StartAddress + i++), Mask, StrMask))
-			++Ign;
-		else if (i >= CodeLen)
-			return 0;
+DWORD FindPattern(DWORD start, DWORD codeLength, BYTE* pattern, unsigned int patternLength) {
+	unsigned int matchLength = 0;
+	for (DWORD ptr = start; ptr <= start + codeLength - patternLength; ptr++) {
+		while (((BYTE*)ptr)[matchLength] == pattern[matchLength]) {
+			matchLength++;
+			if (matchLength == patternLength) return ptr;
+		}
+		matchLength = 0;
 	}
-	return StartAddress + i - 1;
+	return NULL;
 }
 
 DWORD WINAPI Start(LPVOID lpParam)
 {
-	char patternMask[patternLength + 1];
-	for (int i = 0; i < patternLength; i++) patternMask[i] = 'x';
-	patternMask[patternLength] = 0;
 	DWORD target;
 	for (int count = 0; count < 10; count++) {
-		target = FindPattern(0x401000, 0xE52000, pattern, patternMask, 0);
-		if (target) 
-			break; 
-		else 
-			Sleep(300); //pattern not found, try again in 300ms, max 10 times
+		target = FindPattern(0x401000, 0xE52000, pattern, PATTERN_LENGTH);
+		if(!target) Sleep(300); //pattern not found, try again in 300ms, max 10 times
 	}
 	if (target) {
 		//pattern found, remove write protection and overwrite target code
 		DWORD originalProtection;
-		VirtualProtect((void*)target, patternLength, PAGE_EXECUTE_READWRITE, &originalProtection);
-		BYTE* ptr = (BYTE*)target;
-		ptr[0x0F] = 0x85;
-		ptr[0x10] = 0xC0;
-		ptr[0x11] = 0x74;
-		ptr[0x12] = 0x6D;
-		ptr[0x13] = 0xEB;
-		ptr[0x14] = 0x6F;
-		ptr[0x84] = 0x83;
-		ptr[0x85] = 0x78;
-		ptr[0x86] = 0x54;
-		ptr[0x87] = 0x00;
-		ptr[0x88] = 0x74;
-		ptr[0x89] = 0xF6;
-		ptr[0x8A] = 0xEB;
-		ptr[0x8B] = 0x89;
-		VirtualProtect((void*)target, patternLength, originalProtection, NULL);
+		VirtualProtect((void*)target, PATTERN_LENGTH, PAGE_EXECUTE_READWRITE, &originalProtection);
+		((BYTE*)target)[0x0F] = 0x85;
+		((BYTE*)target)[0x10] = 0xC0;
+		((BYTE*)target)[0x11] = 0x74;
+		((BYTE*)target)[0x12] = 0x6D;
+		((BYTE*)target)[0x13] = 0xEB;
+		((BYTE*)target)[0x14] = 0x6F;
+		((BYTE*)target)[0x84] = 0x83;
+		((BYTE*)target)[0x85] = 0x78;
+		((BYTE*)target)[0x86] = 0x54;
+		((BYTE*)target)[0x87] = 0x00;
+		((BYTE*)target)[0x88] = 0x74;
+		((BYTE*)target)[0x89] = 0xF6;
+		((BYTE*)target)[0x8A] = 0xEB;
+		((BYTE*)target)[0x8B] = 0x89;
+		VirtualProtect((void*)target, PATTERN_LENGTH, originalProtection, NULL);
 		return 0;
 	} else {
 		//pattern not found, display error
diff --git a/README.md b/README.md
index e2ead7a..78ad7a7 100644
--- a/README.md
+++ b/README.md
@@ -2,9 +2,7 @@
 
 This ASI mod fixes a crash that occurs on modern systems at the end of Kasumi's loyalty mission, when returning to Normandy after defeating the boss.
 
-For use with Erik-JS's [Binkw32 proxy DLL](https://github.com/Erik-JS/masseffect-binkw32)
-
-__Consider this an EXPERIMENTAL fix: I'm currently doing a complete run of the game on Windows 10 to see if it causes problems elsewhere__
+__For use with Erik-JS's [Binkw32 proxy DLL](https://github.com/Erik-JS/masseffect-binkw32)__
 
 It should work with all versions of the game: Steam, Origin, Disc and "DRM-free 😏".