putting the comment once

include/ada/scheme-inl.h

@@ -22,22 +22,31 @@ constexpr std::string_view is_special_list[] = {"http", " ",   "https", "ws",
 constexpr uint16_t special_ports[] = {80, 0, 443, 80, 21, 443, 0, 0};
 }  // namespace details
 
+/****
+ * In is_special, get_scheme_type, and get_special_port, we
+ * use a standard hashing technique to find the index of the scheme in the
+ * is_special_list. The hashing technique is based on the size of the scheme
+ * and the first character of the scheme. It ensures that we do at most one
+ * string comparison per call. If the protocol is predictible (e.g., it is
+ * always "http"), we can get a better average performance by using a a
+ * simpler approach where we loop and compare scheme with all possible
+ * protocol. In this instance, we choose a potentially slightly lower
+ * best-case performance for a better worst-case performance.
+ *
+ * Reference:
+ * Schmidt, Douglas C. "Gperf: A perfect hash function generator." More C++
+ * gems 17 (2000).
+ *
+ * Reference: https://en.wikipedia.org/wiki/Perfect_hash_function
+ *
+ * Reference: https://github.com/ada-url/ada/issues/617
+ ****/
+
+
 ada_really_inline constexpr bool is_special(std::string_view scheme) {
   if (scheme.empty()) {
     return false;
   }
-  /**
-   * We use a standard hashing technique to find the index of the scheme in the
-   * is_special_list. The hashing technique is based on the size of the scheme
-   * and the first character of the scheme. It ensures that we do at most one
-   * string comparison per call. If the protocol is predictible (e.g., it is
-   * always "http"), we can get a better average performance by using a a
-   * simpler approach where we loop and compare scheme with all possible
-   * protocol. In this instance, we choose a potentially slightly lower
-   * best-case performance for a better worst-case performance. Reference:
-   * Schmidt, Douglas C. "Gperf: A perfect hash function generator." More C++
-   * gems 17 (2000).
-   */
   int hash_value = (2 * scheme.size() + (unsigned)(scheme[0])) & 7;
   const std::string_view target = details::is_special_list[hash_value];
   return (target[0] == scheme[0]) && (target.substr(1) == scheme.substr(1));
@@ -46,18 +55,6 @@ constexpr uint16_t get_special_port(std::string_view scheme) noexcept {
   if (scheme.empty()) {
     return 0;
   }
-  /**
-   * We use a standard hashing technique to find the index of the scheme in the
-   * is_special_list. The hashing technique is based on the size of the scheme
-   * and the first character of the scheme. It ensures that we do at most one
-   * string comparison per call. If the protocol is predictible (e.g., it is
-   * always "http"), we can get a better average performance by using a a
-   * simpler approach where we loop and compare scheme with all possible
-   * protocol. In this instance, we choose a potentially slightly lower
-   * best-case performance for a better worst-case performance. Reference:
-   * Schmidt, Douglas C. "Gperf: A perfect hash function generator." More C++
-   * gems 17 (2000).
-   */
   int hash_value = (2 * scheme.size() + (unsigned)(scheme[0])) & 7;
   const std::string_view target = details::is_special_list[hash_value];
   if ((target[0] == scheme[0]) && (target.substr(1) == scheme.substr(1))) {
@@ -73,18 +70,6 @@ constexpr ada::scheme::type get_scheme_type(std::string_view scheme) noexcept {
   if (scheme.empty()) {
     return ada::scheme::NOT_SPECIAL;
   }
-  /**
-   * We use a standard hashing technique to find the index of the scheme in the
-   * is_special_list. The hashing technique is based on the size of the scheme
-   * and the first character of the scheme. It ensures that we do at most one
-   * string comparison per call. If the protocol is predictible (e.g., it is
-   * always "http"), we can get a better average performance by using a a
-   * simpler approach where we loop and compare scheme with all possible
-   * protocol. In this instance, we choose a potentially slightly lower
-   * best-case performance for a better worst-case performance. Reference:
-   * Schmidt, Douglas C. "Gperf: A perfect hash function generator." More C++
-   * gems 17 (2000).
-   */
   int hash_value = (2 * scheme.size() + (unsigned)(scheme[0])) & 7;
   const std::string_view target = details::is_special_list[hash_value];
   if ((target[0] == scheme[0]) && (target.substr(1) == scheme.substr(1))) {