C++ (Cpp) string::before_last示例

ST::string cdUp(ST::string path) {
    // Check for root paths, we can't go up from there!
#ifdef _WIN32
    if (path.substr(1) == ":\\")
        return path;
#else
    if (path == "/")
        return path;
#endif

    // Not very robust, but it works for one level of parent scanning
    if (path.is_empty())
        return ".." PATHSEPSTR;

    // Strip the ending slash, if necessary, and then go up one dir
    if (path.char_at(path.size()-1) == PATHSEP)
        path = path.left(path.size() - 1);
    ST::string up = path.before_last(PATHSEP);
    if (path.char_at(0) == PATHSEP) {
        // Absolute path specified -- make sure we keep it that way
        return up + PATHSEPSTR;
    } else {
        // Relative path specified
        return up.is_empty() ? "" : up + PATHSEPSTR;
    }
}