Update toolbox.cpp

Author: yourpwnguy

src/rp/toolbox.cpp

@@ -30,19 +30,15 @@ std::string verbosity_to_string(const VerbosityLevel lvl) {
 
 // Get the size of an open file without changing its position
 std::streampos get_file_size(std::ifstream &file) {
-
-  // Save the current file ptr position
   std::streampos backup = file.tellg();
 
-  // Move the ptr to the end
-  file.seekg(0, std::ios::end);
-
-  // Get the current file ptr position ( start = 0 + EOF )
+  file.seekg(0, std::ios::beg);
   std::streampos fsize = file.tellg();
 
-  // Restore the previous ptr position
-  file.seekg(backup);
+  file.seekg(0, std::ios::end);
+  fsize = file.tellg() - fsize;
 
+  file.seekg(backup);
   return fsize;
 }