Avoid integer overflow in loadFile

Author: echo-devim

src/core/hexeditor.cpp

@@ -98,10 +98,13 @@ bool HexEditor::loadFile(string path) {
     this->current_data.clear();
     this->current_data.shrink_to_fit();
 
+    ifs.seekg(0, std::ios::end);
+    this->fileSize = ifs.tellg();
+    ifs.seekg(0, std::ios::beg);
+
     // copies all data into buffer
     this->current_data.insert(this->current_data.begin(), std::istreambuf_iterator<char>(ifs), {});
 
-    this->fileSize = this->current_data.size();
     this->bytesRead = this->fileSize;
 
     return true;