overload

esphome/core/helpers.cpp

@@ -238,27 +238,28 @@ std::string str_sprintf(const char *fmt, ...) {
 // Maximum size for name with suffix: 120 (max friendly name) + 1 (separator) + 6 (MAC suffix) + 1 (null term)
 static constexpr size_t MAX_NAME_WITH_SUFFIX_SIZE = 128;
 
-std::string make_name_with_suffix(const std::string &name, char sep, const char *suffix_ptr, size_t suffix_len) {
+std::string make_name_with_suffix(const char *name, char sep, const char *suffix_ptr, size_t suffix_len) {
   char buffer[MAX_NAME_WITH_SUFFIX_SIZE];
-  size_t name_len = name.size();
+  size_t name_len = strlen(name);
   size_t total_len = name_len + 1 + suffix_len;
 
   // Silently truncate if needed: prioritize keeping the full suffix
   if (total_len >= MAX_NAME_WITH_SUFFIX_SIZE) {
-    // NOTE: This calculation could underflow if suffix_len >= MAX_NAME_WITH_SUFFIX_SIZE - 2,
-    // but this is safe because this helper is only called with small suffixes:
-    // MAC suffixes (6-12 bytes), ".local" (5 bytes), etc.
     name_len = MAX_NAME_WITH_SUFFIX_SIZE - suffix_len - 2;  // -2 for separator and null terminator
     total_len = name_len + 1 + suffix_len;
   }
 
-  memcpy(buffer, name.c_str(), name_len);
+  memcpy(buffer, name, name_len);
   buffer[name_len] = sep;
   memcpy(buffer + name_len + 1, suffix_ptr, suffix_len);
   buffer[total_len] = '\0';
   return std::string(buffer, total_len);
 }
 
+std::string make_name_with_suffix(const std::string &name, char sep, const char *suffix_ptr, size_t suffix_len) {
+  return make_name_with_suffix(name.c_str(), sep, suffix_ptr, suffix_len);
+}
+
 // Parsing & formatting
 
 size_t parse_hex(const char *str, size_t length, uint8_t *data, size_t count) {

esphome/core/helpers.h

@@ -512,6 +512,15 @@ std::string __attribute__((format(printf, 1, 2))) str_sprintf(const char *fmt, .
 /// @return The concatenated string: name + sep + suffix
 std::string make_name_with_suffix(const std::string &name, char sep, const char *suffix_ptr, size_t suffix_len);
 
+/// Optimized string concatenation: name + separator + suffix (const char* overload)
+/// Uses a fixed stack buffer to avoid heap allocations.
+/// @param name The base name (null-terminated string)
+/// @param sep Single character separator
+/// @param suffix_ptr Pointer to the suffix characters
+/// @param suffix_len Length of the suffix
+/// @return The concatenated string: name + sep + suffix
+std::string make_name_with_suffix(const char *name, char sep, const char *suffix_ptr, size_t suffix_len);
+
 ///@}
 
 /// @name Parsing & formatting