FFileReader::IsEof() doesn't work with text files

Config file didn't read with recent changes in code.
- Added appError() for this situation.
- Returned to use "binary file" mode for reading configs.

Author: gildor2

UmodelTool/UmodelSettings.cpp

@@ -207,7 +207,7 @@ void CUmodelSettings::Load()
 	FString ConfigFile;
 	SetPathOption(ConfigFile, CONFIG_FILE);
 
-	FArchive* Ar = new FFileReader(*ConfigFile, FAO_TextFile|FAO_NoOpenError);
+	FArchive* Ar = new FFileReader(*ConfigFile, FAO_NoOpenError); // can't use FAO_TextFile because of FFileReader::IsEof will not work fine with it
 	if (!Ar->IsOpen())
 	{
 		delete Ar;

Unreal/UnCoreSerialize.cpp

@@ -729,23 +729,26 @@ int64 FFileReader::GetFileSize64() const
 	// lazy file size computation
 	if (FileSize < 0)
 	{
-#if _WIN32
 		FFileReader* _this = const_cast<FFileReader*>(this);
-		// don't rewind file back
-		_this->FilePos = _this->FileSize = _filelengthi64(fileno(f));
-		_this->SeekPos = 0;
+#if _WIN32
+		_this->FileSize = _filelengthi64(fileno(f));
 #else
 		fseeko64(f, 0, SEEK_END);
-		FFileReader* _this = const_cast<FFileReader*>(this);
-		// don't rewind file back
-		_this->FilePos = _this->FileSize = ftello64(f);
+		_this->FileSize = ftello64(f);
+		fseeko64(f, 0, FilePos);
 #endif // _WIN32
 	}
 	return FileSize;
 }
 
 bool FFileReader::IsEof() const
 {
+	if (Options & FAO_TextFile)
+	{
+		// We're tracking file position as it returned by our read operations, however "text file" means
+		// skipping "\r" characters, so position may not match.
+		appError("FFileReader::IsEof is not suitable for text files (%s)", FullName);
+	}
 	return (BufferBytesLeft == 0) && (FilePos == GetFileSize64());
 }