[FOLD] in place algorithm

include/boost/url/impl/url.ipp

@@ -145,194 +145,10 @@ relative(
 {
     BOOST_ASSERT(&dest != &base);
     BOOST_ASSERT(&dest != &href);
-
-    // Validate input
-    if (!href.is_path_absolute() ||
-        !base.is_path_absolute())
-    {
-        // href is already relative or
-        // cannot calculate a URI relative to another relative URI
-        BOOST_URL_RETURN_EC(error::not_a_base);
-    }
-
-    // Resolve scheme
-    if (href.scheme() == base.scheme() ||
-        !href.has_scheme())
-    {
-        dest.remove_scheme();
-    }
-    else
-    {
-        dest.set_scheme(href.scheme());
-    }
-
-    // Resolve authority
-    if (dest.has_scheme() ||
-        href.has_authority() != base.has_authority() ||
-        href.authority() != base.authority() ||
-        href.has_userinfo() ||
-        href.has_password())
-    {
-        // Otherwise, copy all but scheme from href
-        if (href.has_authority())
-            dest.set_encoded_authority(href.encoded_authority());
-        else
-            dest.remove_authority();
-        dest.set_encoded_path(href.encoded_path());
-        dest.normalize_path();
-        if (href.has_query())
-            dest.set_encoded_query(href.encoded_query());
-        else
-            dest.remove_query();
-        if (href.has_fragment())
-            dest.set_encoded_fragment(href.encoded_fragment());
-        else
-            dest.remove_fragment();
-        return {};
-    }
-    dest.remove_authority();
-
-    // Resolve new path
-    dest.set_encoded_path({});
-
-    // 0. Get segments
-    auto segs0 = base.segments();
-    auto segs1 = href.segments();
-
-    // Reference iterators
-    auto const begin0 = segs0.begin();
-    auto it0 = begin0;
-    auto const end0 = segs0.end();
-    auto const last0 = begin0 != end0 ? std::prev(end0) : end0;
-    auto const begin1 = segs1.begin();
-    auto it1 = begin1;
-    auto const end1 = segs1.end();
-    auto const last1 = begin0 != end1 ? std::prev(end1) : end1;
-
-    // Function to advance the dotdot segments
-    decode_view dotdot("..");
-    decode_view dot(".");
-    auto consume_dots = [dotdot, dot](
-        segments_view::iterator& first,
-        segments_view::iterator last)
-    {
-        if (*first == dotdot ||
-            *first == dot)
-        {
-            ++first;
-            return true;
-        }
-        auto it = std::next(first);
-        std::size_t l = 1;
-        while (it != last)
-        {
-            if (*it == dotdot)
-            {
-                if (--l == 0)
-                {
-                    ++it;
-                    first = it;
-                    break;
-                }
-            }
-            else if (*it != dot)
-            {
-                ++l;
-            }
-            ++it;
-        }
-        return first == it;
-    };
-
-    // 1. Find the longest common path
-    while (
-        it0 != last0 &&
-        it1 != last1)
-    {
-        if (consume_dots(it0, last0))
-            continue;
-        if (consume_dots(it1, last1))
-            continue;
-        if (*it0 == *it1)
-        {
-            ++it0;
-            ++it1;
-        }
-        else
-        {
-            break;
-        }
-    }
-
-    // 1.b Check if parent paths are the same
-    if (it0 == last0 &&
-        it1 == last1 &&
-        it0 != end0 &&
-        it1 != end1 &&
-        *it0 == *it1)
-    {
-        // Return empty path
-        if (href.has_query())
-            dest.set_encoded_query(href.encoded_query());
-        else
-            dest.remove_query();
-        if (href.has_fragment())
-            dest.set_encoded_fragment(href.encoded_fragment());
-        else
-            dest.remove_fragment();
-        return {};
-    }
-
-    // 2. Append ".." for each segment left in base
-    segments_encoded segs = dest.encoded_segments();
-    if (it0 != end0)
-    {
-        dest.set_path_absolute(false);
-        while (it0 != last0)
-        {
-            if (*it0 == dotdot)
-            {
-                if (!segs.empty())
-                    segs.pop_back();
-            }
-            else if (*it0 != dot)
-            {
-                segs.push_back(dotdot.encoded());
-            }
-            ++it0;
-        }
-    }
-
-    // 3. Append segments left from the reference
-    while (it1 != end1)
-    {
-        if (*it1 == dotdot)
-        {
-            if (!segs.empty())
-                segs.pop_back();
-        }
-        else if (*it1 != dot)
-        {
-            segs.push_back((*it1).encoded());
-        }
-        ++it1;
-    }
-
-    // Query and fragment comes from reference
-    if (href.has_query())
-        dest.set_encoded_query(href.encoded_query());
-    else
-        dest.remove_query();
-
-    if (href.has_fragment())
-        dest.set_encoded_fragment(href.encoded_fragment());
-    else
-        dest.remove_fragment();
-
-    return {};
+    dest.copy(base);
+    return dest.relative(href);
 }
 
-
 } // urls
 } // boost