Method increment_v3

src/path.cpp:1164–1216

namespace detail {

BOOST_FILESYSTEM_DECL void path_algorithms::increment_v3(path_detail::path_iterator& it)
{
    const size_type size = it.m_path_ptr->m_pathname.size();
    BOOST_ASSERT_MSG(it.m_pos < size, "path::iterator increment past end()");

    // increment to position past current element; if current element is implicit dot,
    // this will cause m_pos to represent the end iterator
    it.m_pos += it.m_element.m_pathname.size();

    // if the end is reached, we are done
    if (it.m_pos >= size)
    {
        BOOST_ASSERT_MSG(it.m_pos == size, "path::iterator increment after the referenced path was modified");
        it.m_element.clear(); // aids debugging
        return;
    }

    // process separator (Windows drive spec is only case not a separator)
    if (detail::is_directory_separator(it.m_path_ptr->m_pathname[it.m_pos]))
    {
        size_type root_name_size = 0;
        size_type root_dir_pos = find_root_directory_start(it.m_path_ptr->m_pathname.c_str(), size, root_name_size);

        // detect root directory and set iterator value to the separator if it is
        if (it.m_pos == root_dir_pos && it.m_element.m_pathname.size() == root_name_size)
        {
            it.m_element.m_pathname = path::separator; // generic format; see docs
            return;
        }

        // skip separators until m_pos points to the start of the next element
        while (it.m_pos != size && detail::is_directory_separator(it.m_path_ptr->m_pathname[it.m_pos]))
        {
            ++it.m_pos;
        }

        // detect trailing separator, and treat it as ".", per POSIX spec
        if (it.m_pos == size &&
            !is_root_separator(it.m_path_ptr->m_pathname, root_dir_pos, it.m_pos - 1))
        {
            --it.m_pos;
            it.m_element = detail::dot_path();
            return;
        }
    }

    // get m_element
    size_type end_pos = it.m_path_ptr->m_pathname.find_first_of(separators, it.m_pos);
    if (end_pos == string_type::npos)
        end_pos = size;
    const path::value_type* p = it.m_path_ptr->m_pathname.c_str();
    it.m_element.m_pathname.assign(p + it.m_pos, p + end_pos);
}

BOOST_FILESYSTEM_DECL void path_algorithms::increment_v4(path_detail::path_iterator& it)
{