Add helper functions to get last path segment

src/music/midifile.cpp

@@ -1051,12 +1051,7 @@ std::string MidiFile::GetSMFFile(const MusicSongInfo &song)
 
 	char basename[MAX_PATH];
 	{
-		const char *fnstart = strrchr(song.filename.c_str(), PATHSEPCHAR);
-		if (fnstart == nullptr) {
-			fnstart = song.filename.c_str();
-		} else {
-			fnstart++;
-		}
+		const char *fnstart = StrLastPathSegment(song.filename);
 
 		/* Remove all '.' characters from filename */
 		char *wp = basename;

src/network/network_survey.cpp

@@ -150,13 +150,7 @@ static void SurveyConfiguration(nlohmann::json &survey)
 {
 	survey["network"] = _networking ? (_network_server ? "server" : "client") : "no";
 	if (_current_language != nullptr) {
-		std::string_view language_basename(_current_language->file);
-		auto e = language_basename.rfind(PATHSEPCHAR);
-		if (e != std::string::npos) {
-			language_basename = language_basename.substr(e + 1);
-		}
-
-		survey["language"]["filename"] = language_basename;
+		survey["language"]["filename"] = StrLastPathSegment(_current_language->file);
 		survey["language"]["name"] = _current_language->name;
 		survey["language"]["isocode"] = _current_language->isocode;
 	}

src/string.cpp

@@ -420,6 +420,17 @@ void StrTrimInPlace(std::string &str)
 	StrRightTrimInPlace(str);
 }
 
+const char *StrLastPathSegment(const char *path)
+{
+	const char *best = path;
+	for (; *path != '\0'; path++) {
+		if (*path == PATHSEPCHAR || *path == '/') {
+			if (*(path + 1) != '\0') best = path + 1;
+		}
+	}
+	return best;
+}
+
 /**
  * Check whether the given string starts with the given prefix.
  * @param str    The string to look at.

src/string_func.h

@@ -66,6 +66,13 @@ bool strtolower(std::string &str, std::string::size_type offs = 0);
 [[nodiscard]] bool StrValid(const char *str, const char *last) NOACCESS(2);
 void StrTrimInPlace(std::string &str);
 
+const char *StrLastPathSegment(const char *path);
+
+inline const char *StrLastPathSegment(const std::string &path)
+{
+	return StrLastPathSegment(path.c_str());
+}
+
 [[nodiscard]] bool StrStartsWith(const std::string_view str, const std::string_view prefix);
 [[nodiscard]] bool StrStartsWithIgnoreCase(std::string_view str, const std::string_view prefix);
 [[nodiscard]] bool StrEndsWith(const std::string_view str, const std::string_view suffix);

src/strings.cpp

@@ -2268,7 +2268,7 @@ bool ReadLanguagePack(const LanguageMetadata *lang)
 	_current_language = lang;
 	const TextDirection old_text_dir = _current_text_dir;
 	_current_text_dir = (TextDirection)_current_language->text_dir;
-	const char *c_file = strrchr(_current_language->file, PATHSEPCHAR) + 1;
+	const char *c_file = StrLastPathSegment(_current_language->file);
 	_config_language_file = c_file;
 	SetCurrentGrfLangID(_current_language->newgrflangid);
 
@@ -2444,7 +2444,7 @@ void InitializeLanguagePacks()
 		/* We are trying to find a default language. The priority is by
 		 * configuration file, local environment and last, if nothing found,
 		 * English. */
-		const char *lang_file = strrchr(lng.file, PATHSEPCHAR) + 1;
+		const char *lang_file = StrLastPathSegment(lng.file);
 		if (_config_language_file == lang_file) {
 			chosen_language = &lng;
 			break;