From b4fc237823a13cfa563475b555ffc3b4c8ea560b Mon Sep 17 00:00:00 2001
From: Duncan Ogilvie <mr.exodia.tpodt@gmail.com>
Date: Mon, 3 Jan 2022 05:20:09 +0100
Subject: [PATCH] Only use the new string detection algorithm in certain code
 pages

---
 src/dbg/_exports.cpp      |  7 ++++
 src/dbg/debugger.cpp      |  1 +
 src/dbg/debugger.h        |  1 +
 src/dbg/disasm_helper.cpp | 80 ++++++++++++++++++++++++---------------
 4 files changed, 58 insertions(+), 31 deletions(-)

diff --git a/src/dbg/_exports.cpp b/src/dbg/_exports.cpp
index 93654720..72acce37 100644
--- a/src/dbg/_exports.cpp
+++ b/src/dbg/_exports.cpp
@@ -1203,6 +1203,13 @@ extern "C" DLL_EXPORT duint _dbg_sendmessage(DBGMSG type, void* param1, void* pa
             maxSkipExceptionCount = setting;
         else
             BridgeSettingSetUint("Engine", "MaxSkipExceptionCount", maxSkipExceptionCount);
+
+        duint newStringAlgorithm = 0;
+        if(!BridgeSettingGetUint("Engine", "NewStringAlgorithm", &newStringAlgorithm))
+        {
+            auto acp = GetACP();
+            newStringAlgorithm = acp == 932 || acp == 936 || acp == 949 || acp == 950 || acp == 951 || acp == 1251;
+        }
     }
     break;
 
diff --git a/src/dbg/debugger.cpp b/src/dbg/debugger.cpp
index 65e26cd6..8c73cfd9 100644
--- a/src/dbg/debugger.cpp
+++ b/src/dbg/debugger.cpp
@@ -87,6 +87,7 @@ bool bVerboseExceptionLogging = true;
 bool bNoWow64SingleStepWorkaround = false;
 bool bTraceBrowserNeedsUpdate = false;
 bool bForceLoadSymbols = false;
+bool bNewStringAlgorithm = false;
 duint DbgEvents = 0;
 duint maxSkipExceptionCount = 0;
 HANDLE mProcHandle;
diff --git a/src/dbg/debugger.h b/src/dbg/debugger.h
index ca3a68ce..62822f01 100644
--- a/src/dbg/debugger.h
+++ b/src/dbg/debugger.h
@@ -149,6 +149,7 @@ extern bool bNoForegroundWindow;
 extern bool bVerboseExceptionLogging;
 extern bool bNoWow64SingleStepWorkaround;
 extern bool bForceLoadSymbols;
+extern bool bNewStringAlgorithm;
 extern duint maxSkipExceptionCount;
 extern HANDLE mProcHandle;
 extern HANDLE mForegroundHandle;
diff --git a/src/dbg/disasm_helper.cpp b/src/dbg/disasm_helper.cpp
index 455d40c3..05235d81 100644
--- a/src/dbg/disasm_helper.cpp
+++ b/src/dbg/disasm_helper.cpp
@@ -308,41 +308,59 @@ bool isunicodestring(const WString & data)
 // These functions are exported so that plugins can use this to detect a string, or replace with a plugin-developed string dection algorithm through hooking
 extern "C" __declspec(dllexport) bool isasciistring(const unsigned char* data, int maxlen)
 {
-    int len = 0;
-    char* safebuffer = new char[maxlen];
-    if(!safebuffer)
-        return false;
-    for(const char* p = (const char*)data; *p && len < maxlen - 1; len++, p++)
+    if(bNewStringAlgorithm)
     {
-        safebuffer[p - (const char*)data] = *p;
-    }
+        int len = 0;
+        char* safebuffer = new char[maxlen];
+        if(!safebuffer)
+            return false;
+        for(const char* p = (const char*)data; *p && len < maxlen - 1; len++, p++)
+        {
+            safebuffer[p - (const char*)data] = *p;
+        }
 
-    if(len < 2)
-    {
+        if(len < 2)
+        {
+            delete[] safebuffer;
+            return false;
+        }
+        safebuffer[len] = 0; // Mark the end of string
+        if(len >= maxlen - 1 && (maxlen % 2) == 0 && (safebuffer[maxlen - 2] & 0x80))
+            safebuffer[maxlen - 2] = 0; // Keep DBCS strings from being chopped in the middle
+
+        String data2;
+        WString wdata2;
+        // Convert to and from Unicode
+        wdata2 = StringUtils::LocalCpToUtf16(safebuffer);
         delete[] safebuffer;
-        return false;
+        if(wdata2.size() < 2)
+            return false;
+        data2 = StringUtils::Utf16ToLocalCp(wdata2);
+        if(data2.size() < 2)
+            return false;
+        // Is the data exactly representable in both ANSI and Unicode?
+        if(memcmp(data2.c_str(), data, data2.size()) != 0)
+            return false;
+        // Filter out bad chars
+        if(!isunicodestring(wdata2))
+            return false;
+        return true;
+    }
+    else
+    {
+        int len = 0;
+        for(const char* p = (const char*)data; *p; len++, p++)
+        {
+            if(len >= maxlen)
+                break;
+        }
+        if(len < 2 || len + 1 >= maxlen)
+            return false;
+        for(int i = 0; i < len; i++)
+            if(!isprint(data[i]) && !isspace(data[i]))
+                return false;
+        return true;
     }
-    safebuffer[len] = 0; // Mark the end of string
-    if(len >= maxlen - 1 && (maxlen % 2) == 0 && (safebuffer[maxlen - 2] & 0x80))
-        safebuffer[maxlen - 2] = 0; // Keep DBCS strings from being chopped in the middle
-
-    String data2;
-    WString wdata2;
-    // Convert to and from Unicode
-    wdata2 = StringUtils::LocalCpToUtf16(safebuffer);
-    delete[] safebuffer;
-    if(wdata2.size() < 2)
-        return false;
-    data2 = StringUtils::Utf16ToLocalCp(wdata2);
-    if(data2.size() < 2)
-        return false;
-    // Is the data exactly representable in both ANSI and Unicode?
-    if(memcmp(data2.c_str(), data, data2.size()) != 0)
-        return false;
-    // Filter out bad chars
-    if(!isunicodestring(wdata2))
-        return false;
-    return true;
 }
 
 extern "C" __declspec(dllexport) bool isunicodestring(const unsigned char* data, int maxlen)