+
+ size_t filename_pos(const StringRef &str) {
+ if (str.size() == 2 &&
+ is_separator(str[0]) &&
+ is_separator(str[1]))
+ return 0;
+
+ if (str.size() > 0 && is_separator(str[str.size() - 1]))
+ return str.size() - 1;
+
+ size_t pos = str.find_last_of(separators, str.size() - 1);
+
+#ifdef LLVM_ON_WIN32
+ if (pos == StringRef::npos)
+ pos = str.find_last_of(':', str.size() - 2);
+#endif
+
+ if (pos == StringRef::npos ||
+ (pos == 1 && is_separator(str[0])))
+ return 0;
+
+ return pos + 1;
+ }
+
+ size_t root_dir_start(const StringRef &str) {
+ // case "c:/"
+#ifdef LLVM_ON_WIN32
+ if (str.size() > 2 &&
+ str[1] == ':' &&
+ is_separator(str[2]))
+ return 2;
+#endif
+
+ // case "//"
+ if (str.size() == 2 &&
+ is_separator(str[0]) &&
+ str[0] == str[1])
+ return StringRef::npos;
+
+ // case "//net"
+ if (str.size() > 3 &&
+ is_separator(str[0]) &&
+ str[0] == str[1] &&
+ !is_separator(str[2])) {
+ return str.find_first_of(separators, 2);
+ }
+
+ // case "/"
+ if (str.size() > 0 && is_separator(str[0]))
+ return 0;
+
+ return StringRef::npos;
+ }
+
+ size_t parent_path_end(const StringRef &path) {
+ size_t end_pos = filename_pos(path);
+
+ bool filename_was_sep = path.size() > 0 && is_separator(path[end_pos]);
+
+ // Skip separators except for root dir.
+ size_t root_dir_pos = root_dir_start(StringRef(path.begin(), end_pos));
+
+ while(end_pos > 0 &&
+ (end_pos - 1) != root_dir_pos &&
+ is_separator(path[end_pos - 1]))
+ --end_pos;
+
+ if (end_pos == 1 && root_dir_pos == 0 && filename_was_sep)
+ return StringRef::npos;
+
+ return end_pos;
+ }