diff --git a/source/src/utils/utils.cpp b/source/src/utils/utils.cpp
index 77f9444..fdbc730 100644
--- a/source/src/utils/utils.cpp
+++ b/source/src/utils/utils.cpp
@@ -650,11 +650,24 @@ bool file_replace_or_add_segment(std::string filepath, std::string segment)
     return true;
 }
 
-bool legal_service_name(const std::string &service_name)
-{
-    // legal characters are alphanumeric, and - and _
-    std::regex legal_chars("^[a-zA-Z0-9_-]+$");
-    return std::regex_match(service_name, legal_chars);
+bool legal_service_name(const std::string &service_name) {
+    static bool initialized = false;
+    static bool legal_chars[256] = {false};  // Initialize all to false
+
+    // One-time initialization
+    if (!initialized) {
+        // Set true for valid characters
+        for (unsigned char c : "0123456789"
+                              "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+                              "abcdefghijklmnopqrstuvwxyz"
+                              "._-") {
+            legal_chars[c] = true;
+        }
+        initialized = true;
+    }
+
+    return std::all_of(service_name.begin(), service_name.end(),
+        [](unsigned char c) { return legal_chars[c]; });
 }
 
 } // namespace dropshell 
\ No newline at end of file