From 4ecf386cdad3ff098034b5e28333ad57cca817ff Mon Sep 17 00:00:00 2001
From: "Dirk-Jan C. Binnema" <djcb@djcbsoftware.nl>
Date: Sun, 6 Aug 2023 12:58:02 +0300
Subject: [PATCH] utils-file: don't use regexp in join_paths

It's slow.
---
 lib/utils/mu-utils-file.hh | 32 +++++++++++++++++++++++++++-----
 1 file changed, 27 insertions(+), 5 deletions(-)

diff --git a/lib/utils/mu-utils-file.hh b/lib/utils/mu-utils-file.hh
index 9f429bd7..8edebcbc 100644
--- a/lib/utils/mu-utils-file.hh
+++ b/lib/utils/mu-utils-file.hh
@@ -157,16 +157,38 @@ std::string runtime_path(RuntimePath path, const std::string& muhome="");
  * @return the path
  */
 static inline std::string join_paths() { return {}; }
-template<typename S, typename...Args>
-std::string join_paths(S&& s, Args...args) {
+template<typename S> std::string join_paths_(S&& s) { return std::string{s}; }
+template<typename	S, typename...Args>
+std::string join_paths_(S&& s, Args...args) {
 
 	static std::string sepa{"/"};
 	auto&& str{std::string{std::forward<S>(s)}};
-	if (auto&& rest{join_paths(std::forward<Args>(args)...)}; !rest.empty())
+	if (auto&& rest{join_paths_(std::forward<Args>(args)...)}; !rest.empty())
 		str += (sepa + rest);
+	return str;
+}
 
-	static auto rx = Regex::make("//*").value();
-	return rx.replace(str, sepa);
+template<typename S, typename...Args>
+std::string join_paths(S&& s, Args...args) {
+
+	constexpr auto sepa = '/';
+	auto path = join_paths_(std::forward<S>(s), std::forward<Args>(args)...);
+
+	auto c{0U};
+	while (c < path.size()) {
+
+		if (path[c] != sepa) {
+			++c;
+			continue;
+		}
+
+		while (path[++c] == '/') {
+			path.erase(c, 1);
+			--c;
+		}
+	}
+
+	return path;
 }