Restrict cast types

boot/driver.cc

@@ -76,4 +76,49 @@ namespace elna::boot
             return escape_invalid_char;
         }
     }
+
+    std::optional<std::string> escape_string(const char *escape)
+    {
+        std::string result;
+        const char *current_position = escape + 1;
+
+        while (*current_position != '\0')
+        {
+            if (*current_position == '\\' && *(current_position + 1) == 'x')
+            {
+                current_position += 2;
+
+                std::size_t processed;
+                char character = static_cast<char>(std::stoi(current_position, &processed, 16));
+                if (processed == 0)
+                {
+                    return std::nullopt;
+                }
+                else
+                {
+                    current_position += processed - 1;
+                    result.push_back(character);
+                }
+            }
+            else if (*current_position == '\\')
+            {
+                ++current_position;
+
+                char escape = escape_char(*current_position);
+                if (escape == escape_invalid_char)
+                {
+                    return std::nullopt;
+                }
+                result.push_back(escape);
+            }
+            else
+            {
+                result.push_back(*current_position);
+            }
+            ++current_position;
+        }
+        result.pop_back();
+
+        return result;
+    }
 }