C++ String Split

string_split.cpp

constexpr std::vector<std::string> split(const std::string& str, std::string_view delimiter = " ") {
    std::vector<std::string> xs{};

    int start = 0;
    int end = 0;
    int delimiter_index = 0;
    for (; end < str.size(); ++end) {
        if (str[end] != delimiter[delimiter_index]) [[likely]] {
            end -= delimiter_index;
            delimiter_index = 0;
            continue;
        }

        if (++delimiter_index == delimiter.size()) [[unlikely]] {
            if (auto length = end - start - delimiter.size() + 1; length > 0) {
                xs.push_back(str.substr(start, length));
            }

            start = end + 1;
            delimiter_index = 0;
        }
    }

    if (start < end) xs.push_back(str.substr(start));
    return xs;
}