diff --git a/include/boost/url/detail/impl/url_impl.ipp b/include/boost/url/detail/impl/url_impl.ipp
index ba243bd5..6ddab8ac 100644
--- a/include/boost/url/detail/impl/url_impl.ipp
+++ b/include/boost/url/detail/impl/url_impl.ipp
@@ -42,7 +42,7 @@ apply_userinfo(
 {
     // this function is for
     // authority_view_rule only
-    BOOST_ASSERT(is_authority);
+    BOOST_ASSERT(from_ == from::authority);
 
     // userinfo
     set_size(id_user, user.size());
@@ -71,7 +71,7 @@ apply_host(
 {
     // this function is for
     // authority_view_rule only
-    BOOST_ASSERT(is_authority);
+    BOOST_ASSERT(from_ == from::authority);
 
     // host, port
     host_type_ = ht;
@@ -92,7 +92,7 @@ apply_port(
 {
     // this function is for
     // authority_view_rule only
-    BOOST_ASSERT(is_authority);
+    BOOST_ASSERT(from_ == from::authority);
 
     port_number_ = pn;
     set_size(id_port, 1 + s.size());
@@ -103,12 +103,12 @@ url_impl::
 apply_authority(
     authority_view const& a) noexcept
 {
-    BOOST_ASSERT(! is_authority);
+    BOOST_ASSERT(from_ != from::authority);
 
     // userinfo
     set_size(id_user,
         a.u_.len(id_user) +
-        (is_authority ? 0 : 2));
+        (from_ == from::authority ? 0 : 2));
     set_size(id_pass, a.u_.len(id_pass));
     decoded_[id_user] = a.u_.decoded_[id_user];
     decoded_[id_pass] = a.u_.decoded_[id_pass];
@@ -165,8 +165,19 @@ apply_frag(
 path_ref::
 path_ref(
     url_impl const& impl) noexcept
-    : impl_(&impl)
 {
+    if(impl.from_ == url_impl::from::url)
+    {
+        impl_ = &impl;
+    }
+    else
+    {
+        string_view s = impl.get(id_path);
+        data_ = s.data();
+        size_ = s.size();
+        nseg_ = impl.nseg_;
+        dn_ = impl.decoded_[id_path];
+    }
 }
 
 path_ref::
@@ -254,8 +265,24 @@ query_ref(
 query_ref::
 query_ref(
     url_impl const& impl) noexcept
-    : impl_(&impl)
 {
+    if(impl.from_ == url_impl::from::url)
+    {
+        impl_ = &impl;
+    }
+    else
+    {
+        string_view s = impl.get(id_query);
+        if (!s.empty())
+        {
+            s.remove_prefix(1);
+            question_mark_ = true;
+        }
+        data_ = s.data();
+        size_ = s.size();
+        nparam_ = impl.nparam_;
+        dn_ = impl.decoded_[id_query];
+    }
 }
 
 pct_string_view
@@ -294,7 +321,7 @@ size() const noexcept
         return impl_->len(id_query);
     if(size_ > 0)
         return size_ + 1;
-    return 0;
+    return question_mark_;
 }
 
 // no '?'
diff --git a/include/boost/url/detail/parts_base.hpp b/include/boost/url/detail/parts_base.hpp
index d1958fad..cf2316e4 100644
--- a/include/boost/url/detail/parts_base.hpp
+++ b/include/boost/url/detail/parts_base.hpp
@@ -32,6 +32,18 @@ struct parts_base
         id_frag,        // leading '#'
         id_end          // one past the end
     };
+
+    enum class from : char {
+        // this belongs to a string
+        string,
+        // this belongs to url_base
+        // segments/params containers point to
+        // another url
+        url,
+        // this belongs to authority_view
+        // id_user will not have the leading "//"
+        authority,
+    };
 };
 
 } // detail
diff --git a/include/boost/url/detail/url_impl.hpp b/include/boost/url/detail/url_impl.hpp
index 74af3b56..91b5ee30 100644
--- a/include/boost/url/detail/url_impl.hpp
+++ b/include/boost/url/detail/url_impl.hpp
@@ -52,15 +52,11 @@ struct url_impl : parts_base
     scheme scheme_ =
         urls::scheme::none;
 
-    // true if this belongs to
-    // authority_view. in this case id_user
-    // will not have the leading "//".
-    bool is_authority;
+    from from_ = from::string;
 
-    explicit
     url_impl(
-        bool b) noexcept
-        : is_authority(b)
+        from b) noexcept
+        : from_(b)
     {
     }
 
@@ -152,6 +148,7 @@ class query_ref
     std::size_t size_ = 0;
     std::size_t nparam_ = 0;
     std::size_t dn_ = 0;
+    bool question_mark_ = false;
 
 public:
     query_ref(
diff --git a/include/boost/url/impl/authority_view.ipp b/include/boost/url/impl/authority_view.ipp
index 24d4682c..d8cff4b9 100644
--- a/include/boost/url/impl/authority_view.ipp
+++ b/include/boost/url/impl/authority_view.ipp
@@ -51,7 +51,7 @@ authority_view::
 
 authority_view::
 authority_view() noexcept
-    : u_(true)
+    : u_(from::authority)
 {
 }
 
diff --git a/include/boost/url/impl/params_encoded_ref.ipp b/include/boost/url/impl/params_encoded_ref.ipp
index f5ee5eb6..16af3efe 100644
--- a/include/boost/url/impl/params_encoded_ref.ipp
+++ b/include/boost/url/impl/params_encoded_ref.ipp
@@ -30,7 +30,7 @@ namespace urls {
 params_encoded_ref::
 params_encoded_ref(
     url_base& u) noexcept
-    : params_encoded_base(u.u_)
+    : params_encoded_base(u.impl_)
     , u_(&u)
 {
 }
@@ -229,7 +229,7 @@ find_impl(
     pct_string_view key,
     ignore_case_param ic) const noexcept
 {
-    detail::params_iter_impl end_(u_->u_, 0);
+    detail::params_iter_impl end_(u_->impl_, 0);
     if(! ic)
     {
         for(;;)
@@ -259,13 +259,13 @@ find_last_impl(
     pct_string_view key,
     ignore_case_param ic) const noexcept
 {
-    detail::params_iter_impl begin_(u_->u_);
+    detail::params_iter_impl begin_(u_->impl_);
     if(! ic)
     {
         for(;;)
         {
             if(it.equal(begin_))
-                return { u_->u_, 0 };
+                return { u_->impl_, 0 };
             it.decrement();
             if(*it.key() == *key)
                 return it;
@@ -274,7 +274,7 @@ find_last_impl(
     for(;;)
     {
         if(it.equal(begin_))
-            return { u_->u_, 0 };
+            return { u_->impl_, 0 };
         it.decrement();
         if(grammar::ci_is_equal(
                 *it.key(), *key))
diff --git a/include/boost/url/impl/params_ref.hpp b/include/boost/url/impl/params_ref.hpp
index 76856586..e7cfc6bb 100644
--- a/include/boost/url/impl/params_ref.hpp
+++ b/include/boost/url/impl/params_ref.hpp
@@ -24,7 +24,7 @@ inline
 params_ref::
 params_ref(
     url_base& u) noexcept
-    : params_base(u.u_)
+    : params_base(u.impl_)
     , u_(&u)
 {
 }
diff --git a/include/boost/url/impl/params_ref.ipp b/include/boost/url/impl/params_ref.ipp
index 8b79e9a0..d59105c5 100644
--- a/include/boost/url/impl/params_ref.ipp
+++ b/include/boost/url/impl/params_ref.ipp
@@ -213,7 +213,7 @@ find_impl(
     string_view key,
     ignore_case_param ic) const noexcept
 {
-    detail::params_iter_impl end_(u_->u_, 0);
+    detail::params_iter_impl end_(u_->impl_, 0);
     if(! ic)
     {
         for(;;)
@@ -243,13 +243,13 @@ find_last_impl(
     string_view key,
     ignore_case_param ic) const noexcept
 {
-    detail::params_iter_impl begin_(u_->u_);
+    detail::params_iter_impl begin_(u_->impl_);
     if(! ic)
     {
         for(;;)
         {
             if(it.equal(begin_))
-                return { u_->u_, 0 };
+                return { u_->impl_, 0 };
             it.decrement();
             if(*it.key() == key)
                 return it;
@@ -258,7 +258,7 @@ find_last_impl(
     for(;;)
     {
         if(it.equal(begin_))
-            return { u_->u_, 0 };
+            return { u_->impl_, 0 };
         it.decrement();
         if(grammar::ci_is_equal(
                 *it.key(), key))
diff --git a/include/boost/url/impl/segments_encoded_ref.ipp b/include/boost/url/impl/segments_encoded_ref.ipp
index 21a56caa..8b41c7a6 100644
--- a/include/boost/url/impl/segments_encoded_ref.ipp
+++ b/include/boost/url/impl/segments_encoded_ref.ipp
@@ -28,7 +28,7 @@ segments_encoded_ref::
 segments_encoded_ref(
     url_base& u) noexcept
     : segments_encoded_base(
-        detail::path_ref(u.u_))
+        detail::path_ref(u.impl_))
     , u_(&u)
 {
 }
diff --git a/include/boost/url/impl/segments_ref.ipp b/include/boost/url/impl/segments_ref.ipp
index 8798eb46..9c7fecbc 100644
--- a/include/boost/url/impl/segments_ref.ipp
+++ b/include/boost/url/impl/segments_ref.ipp
@@ -29,7 +29,7 @@ segments_ref::
 segments_ref(
     url_base& u) noexcept
     : segments_base(
-        detail::path_ref(u.u_))
+        detail::path_ref(u.impl_))
     , u_(&u)
 {
 }
diff --git a/include/boost/url/impl/static_url.ipp b/include/boost/url/impl/static_url.ipp
index d436d620..578356d9 100644
--- a/include/boost/url/impl/static_url.ipp
+++ b/include/boost/url/impl/static_url.ipp
@@ -26,7 +26,7 @@ static_url_base(
     s_ = buf;
     cap_ = cap;
     s_[0] = '\0';
-    u_.cs_ = s_;
+    impl_.cs_ = s_;
 }
 
 static_url_base::
@@ -44,9 +44,9 @@ void
 static_url_base::
 clear_impl() noexcept
 {
-    u_ = detail::url_impl(false);
+    impl_ = {from::url};
     s_[0] = '\0';
-    u_.cs_ = s_;
+    impl_.cs_ = s_;
 }
 
 void
diff --git a/include/boost/url/impl/url.ipp b/include/boost/url/impl/url.ipp
index eeed3cbf..36ee042f 100644
--- a/include/boost/url/impl/url.ipp
+++ b/include/boost/url/impl/url.ipp
@@ -43,13 +43,13 @@ url(string_view s)
 
 url::
 url(url&& u) noexcept
-    : url_base(u.u_)
+    : url_base(u.impl_)
 {
     s_ = u.s_;
     cap_ = u.cap_;
     u.s_ = nullptr;
     u.cap_ = 0;
-    u.u_ = detail::url_impl(false);
+    u.impl_ = {from::url};
 }
 
 url&
@@ -58,12 +58,12 @@ operator=(url&& u) noexcept
 {
     if(s_)
         deallocate(s_);
-    u_ = u.u_;
+    impl_ = u.impl_;
     s_ = u.s_;
     cap_ = u.cap_;
     u.s_ = nullptr;
     u.cap_ = 0;
-    u.u_ = detail::url_impl(false);
+    u.impl_ = {from::url};
     return *this;
 }
 
@@ -92,13 +92,13 @@ clear_impl() noexcept
     if(s_)
     {
         // preserve capacity
-        u_ = detail::url_impl(false);
+        impl_ = {from::url};
         s_[0] = '\0';
-        u_.cs_ = s_;
+        impl_.cs_ = s_;
     }
     else
     {
-        BOOST_ASSERT(u_.cs_ ==
+        BOOST_ASSERT(impl_.cs_ ==
             detail::empty_c_str_);
     }
 }
@@ -136,7 +136,7 @@ reserve_impl(
         s_ = allocate(n);
         s_[0] = '\0';
     }
-    u_.cs_ = s_;
+    impl_.cs_ = s_;
 }
 
 void
@@ -158,7 +158,12 @@ swap(url& other) noexcept
         return;
     std::swap(s_, other.s_);
     std::swap(cap_, other.cap_);
-    std::swap(u_, other.u_);
+    std::swap(impl_, other.impl_);
+    std::swap(pi_, other.pi_);
+    if (pi_ == &other.impl_)
+        pi_ = &impl_;
+    if (other.pi_ == &impl_)
+        other.pi_ = &other.impl_;
 }
 
 } // urls
diff --git a/include/boost/url/impl/url_base.ipp b/include/boost/url/impl/url_base.ipp
index 14b29f65..7efd34e9 100644
--- a/include/boost/url/impl/url_base.ipp
+++ b/include/boost/url/impl/url_base.ipp
@@ -58,10 +58,10 @@ op_t::
 url_base::
 op_t::
 op_t(
-    url_base& u_,
+    url_base& impl_,
     string_view* s0_,
     string_view* s1_) noexcept
-    : u(u_)
+    : u(impl_)
     , s0(s0_)
     , s1(s1_)
 {
@@ -123,8 +123,9 @@ copy(url_view_base const& u)
     }
     reserve_impl(
         u.size(), op);
-    u_ = u.u_;
-    u_.cs_ = s_;
+    impl_ = u.impl_;
+    impl_.cs_ = s_;
+    impl_.from_ = {from::url};
     std::memcpy(s_,
         u.data(), u.size());
     s_[size()] = '\0';
@@ -141,10 +142,10 @@ url_base::
 remove_scheme() noexcept
 {
     op_t op(*this);
-    auto const n = u_.len(id_scheme);
+    auto const n = impl_.len(id_scheme);
     if(n == 0)
         return *this;
-    auto const p = u_.offset(id_path);
+    auto const p = impl_.offset(id_path);
     // Check if we are changing
     // path-rootless to path-noscheme
     bool const need_dot =
@@ -152,9 +153,9 @@ remove_scheme() noexcept
     {
         if(has_authority())
             return false;
-        if(u_.nseg_ == 0)
+        if(impl_.nseg_ == 0)
             return false;
-        BOOST_ASSERT(u_.len(id_path) > 0);
+        BOOST_ASSERT(impl_.len(id_path) > 0);
         if(s_[p] == '/')
             return false;
         if(! first_segment().contains(':'))
@@ -165,7 +166,7 @@ remove_scheme() noexcept
     {
         // just remove the scheme
         resize_impl(id_scheme, 0, op);
-        u_.scheme_ = urls::scheme::none;
+        impl_.scheme_ = urls::scheme::none;
         check_invariants();
         return *this;
     }
@@ -181,16 +182,16 @@ remove_scheme() noexcept
     op.move(
         s_ + p - (n - 2),
         s_ + p,
-        u_.offset(id_end) - p);
+        impl_.offset(id_end) - p);
     // adjust part offsets.
     // (p is invalidated)
-    u_.adjust(id_user, id_path, 0-n);
-    u_.adjust(id_query, id_end, 0-(n - 2));
-    auto dest = s_ + u_.offset(id_path);
+    impl_.adjust(id_user, id_path, 0-n);
+    impl_.adjust(id_query, id_end, 0-(n - 2));
+    auto dest = s_ + impl_.offset(id_path);
     dest[0] = '.';
     dest[1] = '/';
     s_[size()] = '\0';
-    u_.scheme_ = urls::scheme::none;
+    impl_.scheme_ = urls::scheme::none;
     return *this;
 }
 
@@ -229,7 +230,7 @@ remove_authority() noexcept
         return *this;
 
     op_t op(*this);
-    if(u_.get(id_path
+    if(impl_.get(id_path
         ).starts_with("//"))
     {
         // prepend "/.", can't throw
@@ -237,17 +238,17 @@ remove_authority() noexcept
             id_user, id_path, 2, op);
         p[0] = '/';
         p[1] = '.';
-        u_.split(id_user, 0);
-        u_.split(id_pass, 0);
-        u_.split(id_host, 0);
-        u_.split(id_port, 0);
+        impl_.split(id_user, 0);
+        impl_.split(id_pass, 0);
+        impl_.split(id_host, 0);
+        impl_.split(id_port, 0);
     }
     else
     {
         resize_impl(
             id_user, id_path, 0, op);
     }
-    u_.host_type_ =
+    impl_.host_type_ =
         urls::host_type::none;
     return *this;
 }
@@ -264,7 +265,7 @@ set_encoded_authority(
     auto n = s.size() + 2;
     auto const need_slash =
         ! is_path_absolute() &&
-        u_.len(id_path) > 0;
+        impl_.len(id_path) > 0;
     if(need_slash)
         ++n;
     auto dest = resize_impl(
@@ -275,9 +276,9 @@ set_encoded_authority(
         s.data(), s.size());
     if(need_slash)
         dest[n - 1] = '/';
-    u_.apply_authority(a);
+    impl_.apply_authority(a);
     if(need_slash)
-        u_.adjust(
+        impl_.adjust(
             id_query, id_end, 1);
     return *this;
 }
@@ -292,15 +293,15 @@ url_base&
 url_base::
 remove_userinfo() noexcept
 {
-    if(u_.len(id_pass) == 0)
+    if(impl_.len(id_pass) == 0)
         return *this; // no userinfo
 
     op_t op(*this);
     // keep authority '//'
     resize_impl(
         id_user, id_host, 2, op);
-    u_.decoded_[id_user] = 0;
-    u_.decoded_[id_pass] = 0;
+    impl_.decoded_[id_user] = 0;
+    impl_.decoded_[id_pass] = 0;
     return *this;
 }
 
@@ -320,24 +321,24 @@ set_userinfo(
         s,
         opt,
         detail::userinfo_chars);
-    auto const pos = u_.get(
+    auto const pos = impl_.get(
         id_user, id_host
             ).find_first_of(':');
     if(pos != string_view::npos)
     {
-        u_.split(id_user, pos);
+        impl_.split(id_user, pos);
         // find ':' in plain string
         auto const pos2 =
             s.find_first_of(':');
-        u_.decoded_[id_user] =
+        impl_.decoded_[id_user] =
             pos2 - 1;
-        u_.decoded_[id_pass] =
+        impl_.decoded_[id_pass] =
             s.size() - pos2;
     }
     else
     {
-        u_.decoded_[id_user] = s.size();
-        u_.decoded_[id_pass] = 0;
+        impl_.decoded_[id_user] = s.size();
+        impl_.decoded_[id_pass] = 0;
     }
     return *this;
 }
@@ -363,7 +364,7 @@ set_encoded_userinfo(
                 detail::password_chars);
         auto dest =
             set_userinfo_impl(n0 + n1 + 1, op);
-        u_.decoded_[id_user] =
+        impl_.decoded_[id_user] =
             detail::re_encode_unchecked(
                 dest,
                 dest + n0,
@@ -371,14 +372,14 @@ set_encoded_userinfo(
                 opt,
                 detail::user_chars);
         *dest++ = ':';
-        u_.decoded_[id_pass] =
+        impl_.decoded_[id_pass] =
             detail::re_encode_unchecked(
                 dest,
                 dest + n1,
                 s1,
                 opt,
                 detail::password_chars);
-        u_.split(id_user, 2 + n0);
+        impl_.split(id_user, 2 + n0);
     }
     else
     {
@@ -387,15 +388,15 @@ set_encoded_userinfo(
             detail::re_encoded_size_unchecked(
                 s, opt, detail::user_chars);
         auto dest = set_userinfo_impl(n, op);
-        u_.decoded_[id_user] =
+        impl_.decoded_[id_user] =
             detail::re_encode_unchecked(
                 dest,
                 dest + n,
                 s,
                 opt,
                 detail::user_chars);
-        u_.split(id_user, 2 + n);
-        u_.decoded_[id_pass] = 0;
+        impl_.split(id_user, 2 + n);
+        impl_.decoded_[id_pass] = 0;
     }
     return *this;
 }
@@ -413,11 +414,11 @@ set_user(string_view s)
     auto dest = set_user_impl(n, op);
     detail::encode_unchecked(
         dest,
-        u_.get(id_pass).data(),
+        impl_.get(id_pass).data(),
         s,
         opt,
         detail::user_chars);
-    u_.decoded_[id_user] = s.size();
+    impl_.decoded_[id_user] = s.size();
     return *this;
 }
 
@@ -432,7 +433,7 @@ set_encoded_user(
         detail::re_encoded_size_unchecked(
             s, opt, detail::user_chars);
     auto dest = set_user_impl(n, op);
-    u_.decoded_[id_user] =
+    impl_.decoded_[id_user] =
         detail::re_encode_unchecked(
             dest,
             dest + n,
@@ -440,7 +441,7 @@ set_encoded_user(
             opt,
             detail::user_chars);
     BOOST_ASSERT(
-        u_.decoded_[id_user] ==
+        impl_.decoded_[id_user] ==
             s.decoded_size());
     return *this;
 }
@@ -451,7 +452,7 @@ url_base&
 url_base::
 remove_password() noexcept
 {
-    auto const n = u_.len(id_pass);
+    auto const n = impl_.len(id_pass);
     if(n < 2)
         return *this; // no password
 
@@ -460,7 +461,7 @@ remove_password() noexcept
     auto dest =
         resize_impl(id_pass, 1, op);
     dest[0] = '@';
-    u_.decoded_[id_pass] = 0;
+    impl_.decoded_[id_pass] = 0;
     return *this;
 }
 
@@ -479,7 +480,7 @@ set_password(string_view s)
         s,
         opt,
         detail::password_chars);
-    u_.decoded_[id_pass] = s.size();
+    impl_.decoded_[id_pass] = s.size();
     return *this;
 }
 
@@ -494,7 +495,7 @@ set_encoded_password(
         detail::re_encoded_size_unchecked(s, opt,
             detail::password_chars);
     auto dest = set_password_impl(n, op);
-    u_.decoded_[id_pass] =
+    impl_.decoded_[id_pass] =
         detail::re_encode_unchecked(
             dest,
             dest + n,
@@ -502,7 +503,7 @@ set_encoded_password(
             opt,
             detail::password_chars);
     BOOST_ASSERT(
-        u_.decoded_[id_pass] ==
+        impl_.decoded_[id_pass] ==
             s.decoded_size());
     return *this;
 }
@@ -583,12 +584,12 @@ set_host(
     auto dest = set_host_impl(n, op);
     encode(
         dest,
-        u_.get(id_path).data(),
+        impl_.get(id_path).data(),
         s,
         opt,
         detail::host_chars);
-    u_.decoded_[id_host] = s.size();
-    u_.host_type_ =
+    impl_.decoded_[id_host] = s.size();
+    impl_.host_type_ =
         urls::host_type::name;
     return *this;
 }
@@ -634,16 +635,16 @@ set_encoded_host(
     auto const n = detail::re_encoded_size_unchecked(
         s, opt, detail::host_chars);
     auto dest = set_host_impl(n, op);
-    u_.decoded_[id_host] =
+    impl_.decoded_[id_host] =
         detail::re_encode_unchecked(
             dest,
-            u_.get(id_path).data(),
+            impl_.get(id_path).data(),
             s,
             opt,
             detail::host_chars);
-    BOOST_ASSERT(u_.decoded_[id_host] ==
+    BOOST_ASSERT(impl_.decoded_[id_host] ==
         s.decoded_size());
-    u_.host_type_ =
+    impl_.host_type_ =
         urls::host_type::name;
     return *this;
 }
@@ -682,12 +683,12 @@ set_host_address(
     auto dest = set_host_impl(n, op);
     encode(
         dest,
-        u_.get(id_path).data(),
+        impl_.get(id_path).data(),
         s,
         opt,
         detail::host_chars);
-    u_.decoded_[id_host] = s.size();
-    u_.host_type_ =
+    impl_.decoded_[id_host] = s.size();
+    impl_.host_type_ =
         urls::host_type::name;
     return *this;
 }
@@ -724,16 +725,16 @@ set_encoded_host_address(
     auto const n = detail::re_encoded_size_unchecked(
         s, opt, detail::host_chars);
     auto dest = set_host_impl(n, op);
-    u_.decoded_[id_host] =
+    impl_.decoded_[id_host] =
         detail::re_encode_unchecked(
             dest,
-            u_.get(id_path).data(),
+            impl_.get(id_path).data(),
             s,
             opt,
             detail::host_chars);
-    BOOST_ASSERT(u_.decoded_[id_host] ==
+    BOOST_ASSERT(impl_.decoded_[id_host] ==
         s.decoded_size());
-    u_.host_type_ =
+    impl_.host_type_ =
         urls::host_type::name;
     return *this;
 }
@@ -748,11 +749,11 @@ set_host_address(
     auto s = addr.to_buffer(buf, sizeof(buf));
     auto dest = set_host_impl(s.size(), op);
     std::memcpy(dest, s.data(), s.size());
-    u_.decoded_[id_host] = u_.len(id_host);
-    u_.host_type_ = urls::host_type::ipv4;
+    impl_.decoded_[id_host] = impl_.len(id_host);
+    impl_.host_type_ = urls::host_type::ipv4;
     auto bytes = addr.to_bytes();
     std::memcpy(
-        u_.ip_addr_,
+        impl_.ip_addr_,
         bytes.data(),
         bytes.size());
     return *this;
@@ -773,11 +774,11 @@ set_host_address(
     auto const n = s.size() + 2;
     auto dest = set_host_impl(n, op);
     std::memcpy(dest, buf, n);
-    u_.decoded_[id_host] = n;
-    u_.host_type_ = urls::host_type::ipv6;
+    impl_.decoded_[id_host] = n;
+    impl_.host_type_ = urls::host_type::ipv6;
     auto bytes = addr.to_bytes();
     std::memcpy(
-        u_.ip_addr_,
+        impl_.ip_addr_,
         bytes.data(),
         bytes.size());
     return *this;
@@ -798,9 +799,9 @@ set_host_ipvfuture(
     *dest++ = '[';
     dest += s.copy(dest, s.size());
     *dest = ']';
-    u_.host_type_ =
+    impl_.host_type_ =
         urls::host_type::ipvfuture;
-    u_.decoded_[id_host] = s.size() + 2;
+    impl_.decoded_[id_host] = s.size() + 2;
     return *this;
 }
 
@@ -831,9 +832,9 @@ set_host_name(
         s,
         opt,
         allowed);
-    u_.host_type_ =
+    impl_.host_type_ =
         urls::host_type::name;
-    u_.decoded_[id_host] = s.size();
+    impl_.decoded_[id_host] = s.size();
     return *this;
 }
 
@@ -858,7 +859,7 @@ set_encoded_host_name(
     auto const n = detail::re_encoded_size_unchecked(
         s, opt, allowed);
     auto dest = set_host_impl(n, op);
-    u_.decoded_[id_host] =
+    impl_.decoded_[id_host] =
         detail::re_encode_unchecked(
             dest,
             dest + n,
@@ -866,9 +867,9 @@ set_encoded_host_name(
             opt,
             allowed);
     BOOST_ASSERT(
-        u_.decoded_[id_host] ==
+        impl_.decoded_[id_host] ==
             s.decoded_size());
-    u_.host_type_ =
+    impl_.host_type_ =
         urls::host_type::name;
     return *this;
 }
@@ -881,7 +882,7 @@ remove_port() noexcept
 {
     op_t op(*this);
     resize_impl(id_port, 0, op);
-    u_.port_number_ = 0;
+    impl_.port_number_ = 0;
     return *this;
 }
 
@@ -898,7 +899,7 @@ set_port(
     std::memcpy(
         dest, s.string().data(),
             s.string().size());
-    u_.port_number_ = n;
+    impl_.port_number_ = n;
     return *this;
 }
 
@@ -916,9 +917,9 @@ set_port(
     std::memcpy(dest,
         t.str.data(), t.str.size());
     if(t.has_number)
-        u_.port_number_ = t.number;
+        impl_.port_number_ = t.number;
     else
-        u_.port_number_ = 0;
+        impl_.port_number_ = 0;
     return *this;
 }
 
@@ -930,35 +931,35 @@ remove_origin() noexcept
 {
     op_t op(*this);
     check_invariants();
-    if(u_.len(id_scheme,
+    if(impl_.len(id_scheme,
         id_path) == 0)
     {
         // no origin
         return *this;
     }
 
-    u_.decoded_[id_user] = 0;
-    u_.decoded_[id_pass] = 0;
-    u_.decoded_[id_host] = 0;
-    u_.host_type_ =
+    impl_.decoded_[id_user] = 0;
+    impl_.decoded_[id_pass] = 0;
+    impl_.decoded_[id_host] = 0;
+    impl_.host_type_ =
         urls::host_type::none;
-    u_.port_number_ = 0;
+    impl_.port_number_ = 0;
 
     // Check if we will be left with
     // "//" or a rootless segment
     // with a colon
-    auto s = u_.get(id_path);
+    auto s = impl_.get(id_path);
     if(s.starts_with("//"))
     {
         // need "."
         auto dest = resize_impl(
             id_scheme, id_path, 1, op);
         dest[0] = '.';
-        u_.split(id_scheme, 0);
-        u_.split(id_user, 0);
-        u_.split(id_pass, 0);
-        u_.split(id_host, 0);
-        u_.split(id_port, 0);
+        impl_.split(id_scheme, 0);
+        impl_.split(id_user, 0);
+        impl_.split(id_pass, 0);
+        impl_.split(id_host, 0);
+        impl_.split(id_port, 0);
         return *this;
     }
     if( s.empty() ||
@@ -990,11 +991,11 @@ remove_origin() noexcept
         id_scheme, id_path, 2, op);
     dest[0] = '.';
     dest[1] = '/';
-    u_.split(id_scheme, 0);
-    u_.split(id_user, 0);
-    u_.split(id_pass, 0);
-    u_.split(id_host, 0);
-    u_.split(id_port, 0);
+    impl_.split(id_scheme, 0);
+    impl_.split(id_user, 0);
+    impl_.split(id_pass, 0);
+    impl_.split(id_host, 0);
+    impl_.split(id_port, 0);
     return *this;
 }
 
@@ -1012,7 +1013,7 @@ set_path_absolute(
     op_t op(*this);
 
     // check if path empty
-    if(u_.len(id_path) == 0)
+    if(impl_.len(id_path) == 0)
     {
         if(! absolute)
         {
@@ -1024,12 +1025,12 @@ set_path_absolute(
         auto dest = resize_impl(
             id_path, 1, op);
         *dest = '/';
-        ++u_.decoded_[id_path];
+        ++impl_.decoded_[id_path];
         return true;
     }
 
     // check if path absolute
-    if(s_[u_.offset(id_path)] == '/')
+    if(s_[impl_.offset(id_path)] == '/')
     {
         if(absolute)
         {
@@ -1038,7 +1039,7 @@ set_path_absolute(
         }
 
         if( has_authority() &&
-            u_.len(id_path) > 1)
+            impl_.len(id_path) > 1)
         {
             // can't do it, paths are always
             // absolute when authority present!
@@ -1046,10 +1047,10 @@ set_path_absolute(
         }
 
         // remove '/'
-        auto n = u_.len(id_port);
-        u_.split(id_port, n + 1);
+        auto n = impl_.len(id_port);
+        impl_.split(id_port, n + 1);
         resize_impl(id_port, n, op);
-        --u_.decoded_[id_path];
+        --impl_.decoded_[id_path];
         return true;
     }
 
@@ -1060,12 +1061,12 @@ set_path_absolute(
     }
 
     // add '/'
-    auto n = u_.len(id_port);
+    auto n = impl_.len(id_port);
     auto dest = resize_impl(
         id_port, n + 1, op) + n;
-    u_.split(id_port, n);
+    impl_.split(id_port, n);
     *dest = '/';
-    ++u_.decoded_[id_path];
+    ++impl_.decoded_[id_path];
     return true;
 }
 
@@ -1076,9 +1077,9 @@ set_path(
 {
     edit_segments(
         detail::segments_iter_impl(
-            detail::path_ref(u_)),
+            detail::path_ref(impl_)),
         detail::segments_iter_impl(
-            detail::path_ref(u_), 0),
+            detail::path_ref(impl_), 0),
         detail::path_iter(s),
         s.starts_with('/'));
     return *this;
@@ -1091,9 +1092,9 @@ set_encoded_path(
 {
     edit_segments(
         detail::segments_iter_impl(
-            detail::path_ref(u_)),
+            detail::path_ref(impl_)),
         detail::segments_iter_impl(
-            detail::path_ref(u_), 0),
+            detail::path_ref(impl_), 0),
         detail::path_encoded_iter(s),
         s.starts_with('/'));
     return *this;
@@ -1125,8 +1126,8 @@ remove_query() noexcept
 {
     op_t op(*this);
     resize_impl(id_query, 0, op);
-    u_.nparam_ = 0;
-    u_.decoded_[id_query] = 0;
+    impl_.nparam_ = 0;
+    impl_.decoded_[id_query] = 0;
     return *this;
 }
 
@@ -1136,8 +1137,8 @@ set_query(
     string_view s)
 {
     edit_params(
-        detail::params_iter_impl(u_),
-        detail::params_iter_impl(u_, 0),
+        detail::params_iter_impl(impl_),
+        detail::params_iter_impl(impl_, 0),
         detail::query_iter(s, true));
     return *this;
 }
@@ -1185,7 +1186,7 @@ set_encoded_query(
     *dest++ = '?';
 
     // encode
-    u_.decoded_[id_query] =
+    impl_.decoded_[id_query] =
         detail::re_encode_unchecked(
             dest,
             dest + n,
@@ -1193,9 +1194,9 @@ set_encoded_query(
             opt,
             detail::query_chars);
     BOOST_ASSERT(
-        u_.decoded_[id_query] ==
+        impl_.decoded_[id_query] ==
             s.decoded_size());
-    u_.nparam_ = nparam;
+    impl_.nparam_ = nparam;
     return *this;
 }
 
@@ -1225,7 +1226,7 @@ remove_fragment() noexcept
 {
     op_t op(*this);
     resize_impl(id_frag, 0, op);
-    u_.decoded_[id_frag] = 0;
+    impl_.decoded_[id_frag] = 0;
     return *this;
 }
 
@@ -1246,7 +1247,7 @@ set_fragment(string_view s)
         s,
         opt,
         detail::fragment_chars);
-    u_.decoded_[id_frag] = s.size();
+    impl_.decoded_[id_frag] = s.size();
     return *this;
 }
 
@@ -1263,7 +1264,7 @@ set_encoded_fragment(
     auto dest = resize_impl(
         id_frag, n + 1, op);
     *dest++ = '#';
-    u_.decoded_[id_frag] =
+    impl_.decoded_[id_frag] =
         detail::re_encode_unchecked(
             dest,
             dest + n,
@@ -1271,7 +1272,7 @@ set_encoded_fragment(
             opt,
             detail::fragment_chars);
     BOOST_ASSERT(
-        u_.decoded_[id_frag] ==
+        impl_.decoded_[id_frag] ==
             s.decoded_size());
     return *this;
 }
@@ -1309,7 +1310,7 @@ resolve(
     if(ref.has_authority())
     {
         reserve_impl(
-            u_.offset(id_user) + ref.size(), op);
+            impl_.offset(id_user) + ref.size(), op);
         set_encoded_authority(
             ref.encoded_authority());
         set_encoded_path(
@@ -1333,7 +1334,7 @@ resolve(
     if(ref.encoded_path().empty())
     {
         reserve_impl(
-            u_.offset(id_query) +
+            impl_.offset(id_query) +
             ref.size(), op);
         normalize_path();
         if(ref.has_query())
@@ -1349,7 +1350,7 @@ resolve(
     if(ref.is_path_absolute())
     {
         reserve_impl(
-            u_.offset(id_path) +
+            impl_.offset(id_path) +
                 ref.size(), op);
         set_encoded_path(
             ref.encoded_path());
@@ -1368,7 +1369,7 @@ resolve(
     }
     // General case: ref is relative path
     reserve_impl(
-        u_.offset(id_query) +
+        impl_.offset(id_query) +
         ref.size(), op);
     // 5.2.3. Merge Paths
     auto es = encoded_segments();
@@ -1407,8 +1408,8 @@ normalize_octets_impl(
     Charset const& allowed,
     op_t& op) noexcept
 {
-    char* it = s_ + u_.offset(id);
-    char* end = s_ + u_.offset(id + 1);
+    char* it = s_ + impl_.offset(id);
+    char* end = s_ + impl_.offset(id + 1);
     char d = 0;
     char* dest = it;
     while (it < end)
@@ -1444,7 +1445,7 @@ normalize_octets_impl(
     if (it != dest)
     {
         std::size_t diff = it - dest;
-        std::size_t n = u_.len(id) - diff;
+        std::size_t n = impl_.len(id) - diff;
         shrink_impl(id, n, op);
         s_[size()] = '\0';
     }
@@ -1488,8 +1489,8 @@ normalize_path()
     op_t op(*this);
     normalize_octets_impl(id_path, detail::path_chars, op);
     string_view p = encoded_path();
-    char* p_dest = s_ + u_.offset(id_path);
-    char* p_end = s_ + u_.offset(id_path + 1);
+    char* p_dest = s_ + impl_.offset(id_path);
+    char* p_end = s_ + impl_.offset(id_path + 1);
     std::size_t pn = p.size();
     std::size_t skip_dot = 0;
     if (
@@ -1548,18 +1549,18 @@ normalize_path()
             {
                 // prepend with "./"
                 // (resize_impl never throws)
-                std::size_t n = u_.len(id_path);
+                std::size_t n = impl_.len(id_path);
                 resize_impl(
                     id_path,  n + 2, op);
                 std::memmove(
-                    s_ + u_.offset(id_path) + 2,
-                    s_ + u_.offset(id_path),n
+                    s_ + impl_.offset(id_path) + 2,
+                    s_ + impl_.offset(id_path),n
                 );
                 p_dest[0] = '.';
                 p_dest[1] = '/';
                 skip_dot = 2;
                 p = encoded_path();
-                p_end = s_ + u_.offset(id_path + 1);
+                p_end = s_ + impl_.offset(id_path + 1);
             }
         }
     }
@@ -1573,10 +1574,10 @@ normalize_path()
         shrink_impl(id_path, n + skip_dot, op);
         p = encoded_path();
         if (!p.empty())
-            u_.nseg_ = std::count(
+            impl_.nseg_ = std::count(
                 p.begin() + 1, p.end(), '/') + 1;
         else
-            u_.nseg_ = 0;
+            impl_.nseg_ = 0;
     }
     return *this;
 }
@@ -1623,39 +1624,40 @@ void
 url_base::
 check_invariants() const noexcept
 {
+    BOOST_ASSERT(pi_);
     BOOST_ASSERT(
-        u_.len(id_scheme) == 0 ||
-        u_.get(id_scheme).ends_with(':'));
+        impl_.len(id_scheme) == 0 ||
+        impl_.get(id_scheme).ends_with(':'));
     BOOST_ASSERT(
-        u_.len(id_user) == 0 ||
-        u_.get(id_user).starts_with("//"));
+        impl_.len(id_user) == 0 ||
+        impl_.get(id_user).starts_with("//"));
     BOOST_ASSERT(
-        u_.len(id_pass) == 0 ||
-        u_.get(id_user).starts_with("//"));
+        impl_.len(id_pass) == 0 ||
+        impl_.get(id_user).starts_with("//"));
     BOOST_ASSERT(
-        u_.len(id_pass) == 0 ||
-        (u_.len(id_pass) == 1 &&
-            u_.get(id_pass) == "@") ||
-        (u_.len(id_pass) > 1 &&
-            u_.get(id_pass).starts_with(':') &&
-            u_.get(id_pass).ends_with('@')));
+        impl_.len(id_pass) == 0 ||
+        (impl_.len(id_pass) == 1 &&
+            impl_.get(id_pass) == "@") ||
+        (impl_.len(id_pass) > 1 &&
+            impl_.get(id_pass).starts_with(':') &&
+            impl_.get(id_pass).ends_with('@')));
     BOOST_ASSERT(
-        u_.len(id_user, id_path) == 0 ||
-        u_.get(id_user).starts_with("//"));
-    BOOST_ASSERT(u_.decoded_[id_path] >=
-        ((u_.len(id_path) + 2) / 3));
+        impl_.len(id_user, id_path) == 0 ||
+        impl_.get(id_user).starts_with("//"));
+    BOOST_ASSERT(impl_.decoded_[id_path] >=
+        ((impl_.len(id_path) + 2) / 3));
     BOOST_ASSERT(
-        u_.len(id_port) == 0 ||
-        u_.get(id_port).starts_with(':'));
+        impl_.len(id_port) == 0 ||
+        impl_.get(id_port).starts_with(':'));
     BOOST_ASSERT(
-        u_.len(id_query) == 0 ||
-        u_.get(id_query).starts_with('?'));
+        impl_.len(id_query) == 0 ||
+        impl_.get(id_query).starts_with('?'));
     BOOST_ASSERT(
-        (u_.len(id_query) == 0 && u_.nparam_ == 0) ||
-        (u_.len(id_query) > 0 && u_.nparam_ > 0));
+        (impl_.len(id_query) == 0 && impl_.nparam_ == 0) ||
+        (impl_.len(id_query) > 0 && impl_.nparam_ > 0));
     BOOST_ASSERT(
-        u_.len(id_frag) == 0 ||
-        u_.get(id_frag).starts_with('#'));
+        impl_.len(id_frag) == 0 ||
+        impl_.get(id_frag).starts_with('#'));
     BOOST_ASSERT(c_str()[size()] == '\0');
 }
 
@@ -1678,9 +1680,9 @@ resize_impl(
     std::size_t new_len,
     op_t& op)
 {
-    auto const n0 = u_.len(first, last);
+    auto const n0 = impl_.len(first, last);
     if(new_len == 0 && n0 == 0)
-        return s_ + u_.offset(first);
+        return s_ + impl_.offset(first);
     if(new_len <= n0)
         return shrink_impl(
             first, last, new_len, op);
@@ -1689,20 +1691,20 @@ resize_impl(
     std::size_t n = new_len - n0;
     reserve_impl(size() + n, op);
     auto const pos =
-        u_.offset(last);
+        impl_.offset(last);
     // adjust chars
     op.move(
         s_ + pos + n,
         s_ + pos,
-        u_.offset(id_end) -
+        impl_.offset(id_end) -
             pos + 1);
     // collapse (first, last)
-    u_.collapse(first, last,
-        u_.offset(last) + n);
+    impl_.collapse(first, last,
+        impl_.offset(last) + n);
     // shift (last, end) right
-    u_.adjust(last, id_end, n);
+    impl_.adjust(last, id_end, n);
     s_[size()] = '\0';
-    return s_ + u_.offset(first);
+    return s_ + impl_.offset(first);
 }
 
 char*
@@ -1725,25 +1727,25 @@ shrink_impl(
     op_t& op)
 {
     // shrinking
-    auto const n0 = u_.len(first, last);
+    auto const n0 = impl_.len(first, last);
     BOOST_ASSERT(new_len <= n0);
     std::size_t n = n0 - new_len;
     auto const pos =
-        u_.offset(last);
+        impl_.offset(last);
     // adjust chars
     op.move(
         s_ + pos - n,
         s_ + pos,
-        u_.offset(
+        impl_.offset(
             id_end) - pos + 1);
     // collapse (first, last)
-    u_.collapse(first,  last,
-        u_.offset(last) - n);
+    impl_.collapse(first,  last,
+        impl_.offset(last) - n);
     // shift (last, end) left
-    u_.adjust(
+    impl_.adjust(
         last, id_end, 0 - n);
     s_[size()] = '\0';
-    return s_ + u_.offset(first);
+    return s_ + impl_.offset(first);
 }
 
 //------------------------------------------------
@@ -1760,13 +1762,13 @@ set_scheme_impl(
         s, detail::scheme_rule()
             ).value(BOOST_URL_POS);
     auto const n = s.size();
-    auto const p = u_.offset(id_path);
+    auto const p = impl_.offset(id_path);
 
     // check for "./" prefix
     bool const has_dot =
         [this, p]
     {
-        if(u_.nseg_ == 0)
+        if(impl_.nseg_ == 0)
             return false;
         if(first_segment().size() < 2)
             return false;
@@ -1790,9 +1792,9 @@ set_scheme_impl(
             s_ + p + 2,
             size() + 1 -
                 (p + 2));
-        u_.set_size(
+        impl_.set_size(
             id_path,
-            u_.len(id_path) - 2);
+            impl_.len(id_path) - 2);
         s_[size()] = '\0';
     }
 
@@ -1800,7 +1802,7 @@ set_scheme_impl(
         id_scheme, n + 1, op);
     s.copy(dest, n);
     dest[n] = ':';
-    u_.scheme_ = id;
+    impl_.scheme_ = id;
     check_invariants();
 }
 
@@ -1811,7 +1813,7 @@ set_user_impl(
     op_t& op)
 {
     check_invariants();
-    if(u_.len(id_pass) != 0)
+    if(impl_.len(id_pass) != 0)
     {
         // keep "//"
         auto dest = resize_impl(
@@ -1822,7 +1824,7 @@ set_user_impl(
     // add authority
     auto dest = resize_impl(
         id_user, 2 + n + 1, op);
-    u_.split(id_user, 2 + n);
+    impl_.split(id_user, 2 + n);
     dest[0] = '/';
     dest[1] = '/';
     dest[2 + n] = '@';
@@ -1837,7 +1839,7 @@ set_password_impl(
     op_t& op)
 {
     check_invariants();
-    if(u_.len(id_user) != 0)
+    if(impl_.len(id_user) != 0)
     {
         // already have authority
         auto const dest = resize_impl(
@@ -1852,7 +1854,7 @@ set_password_impl(
         resize_impl(
         id_user, id_host,
         2 + 1 + n + 1, op);
-    u_.split(id_user, 2);
+    impl_.split(id_user, 2);
     dest[0] = '/';
     dest[1] = '/';
     dest[2] = ':';
@@ -1871,7 +1873,7 @@ set_userinfo_impl(
     check_invariants();
     auto dest = resize_impl(
         id_user, id_host, n + 3, op);
-    u_.split(id_user, n + 2);
+    impl_.split(id_user, n + 2);
     dest[0] = '/';
     dest[1] = '/';
     dest[n + 2] = '@';
@@ -1886,13 +1888,13 @@ set_host_impl(
     op_t& op)
 {
     check_invariants();
-    if(u_.len(id_user) == 0)
+    if(impl_.len(id_user) == 0)
     {
         // add authority
         auto dest = resize_impl(
             id_user, n + 2, op);
-        u_.split(id_user, 2);
-        u_.split(id_pass, 0);
+        impl_.split(id_user, 2);
+        impl_.split(id_pass, 0);
         dest[0] = '/';
         dest[1] = '/';
         check_invariants();
@@ -1912,7 +1914,7 @@ set_port_impl(
     op_t& op)
 {
     check_invariants();
-    if(u_.len(id_user) != 0)
+    if(impl_.len(id_user) != 0)
     {
         // authority exists
         auto dest = resize_impl(
@@ -1923,9 +1925,9 @@ set_port_impl(
     }
     auto dest = resize_impl(
         id_user, 3 + n, op);
-    u_.split(id_user, 2);
-    u_.split(id_pass, 0);
-    u_.split(id_host, 0);
+    impl_.split(id_user, 2);
+    impl_.split(id_pass, 0);
+    impl_.split(id_host, 0);
     dest[0] = '/';
     dest[1] = '/';
     dest[2] = ':';
@@ -1941,15 +1943,15 @@ string_view
 url_base::
 first_segment() const noexcept
 {
-    if(u_.nseg_ == 0)
+    if(impl_.nseg_ == 0)
         return {};
-    auto const p0 = u_.cs_ +
-        u_.offset(id_path) + 
+    auto const p0 = impl_.cs_ +
+        impl_.offset(id_path) +
             detail::path_prefix(
-                u_.get(id_path));
-    auto const end = u_.cs_ +
-        u_.offset(id_query);
-    if(u_.nseg_ == 1)
+                impl_.get(id_path));
+    auto const end = impl_.cs_ +
+        impl_.offset(id_query);
+    if(impl_.nseg_ == 1)
         return string_view(
             p0, end - p0);
     auto p = p0;
@@ -1971,28 +1973,28 @@ edit_segments(
     int absolute)
 {
     // Iterator doesn't belong to this url
-    BOOST_ASSERT(it0.ref.alias_of(u_));
+    BOOST_ASSERT(it0.ref.alias_of(impl_));
 
     // Iterator doesn't belong to this url
-    BOOST_ASSERT(it1.ref.alias_of(u_));
+    BOOST_ASSERT(it1.ref.alias_of(impl_));
 
     // Iterator is in the wrong order
     BOOST_ASSERT(it0.index <= it1.index);
 
     // Iterator is out of range
-    BOOST_ASSERT(it0.index <= u_.nseg_);
-    BOOST_ASSERT(it0.pos <= u_.len(id_path));
+    BOOST_ASSERT(it0.index <= impl_.nseg_);
+    BOOST_ASSERT(it0.pos <= impl_.len(id_path));
 
     // Iterator is out of range
-    BOOST_ASSERT(it1.index <= u_.nseg_);
-    BOOST_ASSERT(it1.pos <= u_.len(id_path));
+    BOOST_ASSERT(it1.index <= impl_.nseg_);
+    BOOST_ASSERT(it1.pos <= impl_.len(id_path));
 
     bool const is_abs = is_path_absolute();
     if(has_authority())
         absolute = 1; // must be absolute
     else if(absolute < 0)
         absolute = is_abs; // preserve
-    auto const path_pos = u_.offset(id_path);
+    auto const path_pos = impl_.offset(id_path);
 
 //------------------------------------------------
 //
@@ -2028,11 +2030,11 @@ edit_segments(
     {
         // patch pos for prefix
         pos1 = detail::path_prefix(
-            u_.get(id_path));
+            impl_.get(id_path));
     }
     else if(
         it0.index == 0 &&
-        it1.index < u_.nseg_ &&
+        it1.index < impl_.nseg_ &&
         nseg == 0)
     {
         // Remove the slash from segment it1
@@ -2044,8 +2046,8 @@ edit_segments(
     auto const dn0 =
         detail::decode_bytes_unchecked(
             string_view(
-                u_.cs_ +
-                    u_.offset(id_path) +
+                impl_.cs_ +
+                    impl_.offset(id_path) +
                     pos0,
                 pos1 - pos0));
 
@@ -2089,9 +2091,9 @@ edit_segments(
     {
         // first segment from it1
         auto const p =
-            u_.cs_ + path_pos + it1.pos;
-        switch(u_.cs_ +
-            u_.offset(id_query) - p)
+            impl_.cs_ + path_pos + it1.pos;
+        switch(impl_.cs_ +
+            impl_.offset(id_query) - p)
         {
         case 0:
             // points to end
@@ -2124,7 +2126,7 @@ edit_segments(
 //  if inserting at front.
     std::size_t const suffix =
         it1.index == 0 &&
-        u_.nseg_ > 0 &&
+        impl_.nseg_ > 0 &&
         nseg > 0;
 
 //------------------------------------------------
@@ -2158,12 +2160,12 @@ edit_segments(
             dest + nchar,
             s_ + path_pos + pos1,
             size() - path_pos - pos1);
-        u_.set_size(
+        impl_.set_size(
             id_path,
-            u_.len(id_path) + nchar - nremove);
+            impl_.len(id_path) + nchar - nremove);
         BOOST_ASSERT(size() == new_size);
         end = dest + nchar;
-        u_.nseg_ = u_.nseg_ + nseg - (
+        impl_.nseg_ = impl_.nseg_ + nseg - (
             it1.index - it0.index);
         if(s_)
             s_[size()] = '\0';
@@ -2211,10 +2213,10 @@ edit_segments(
     auto const dn =
         detail::decode_bytes_unchecked(
             string_view(dest0, dest - dest0));
-    u_.decoded_[id_path] += dn - dn0;
+    impl_.decoded_[id_path] += dn - dn0;
 
     return detail::segments_iter_impl(
-        u_, pos0, it0.index);
+        impl_, pos0, it0.index);
 }
 
 //------------------------------------------------
@@ -2227,35 +2229,35 @@ edit_params(
     detail::any_params_iter&& src) ->
         detail::params_iter_impl
 {
-    auto pos0 = u_.offset(id_query);
+    auto pos0 = impl_.offset(id_query);
     auto pos1 = pos0 + it1.pos;
     pos0 = pos0 + it0.pos;
 
     // Iterator doesn't belong to this url
-    BOOST_ASSERT(it0.ref.alias_of(u_));
+    BOOST_ASSERT(it0.ref.alias_of(impl_));
 
     // Iterator doesn't belong to this url
-    BOOST_ASSERT(it1.ref.alias_of(u_));
+    BOOST_ASSERT(it1.ref.alias_of(impl_));
 
     // Iterator is in the wrong order
     BOOST_ASSERT(it0.index <= it1.index);
 
     // Iterator is out of range
-    BOOST_ASSERT(it0.index <= u_.nparam_);
-    BOOST_ASSERT(pos0 <= u_.offset(id_frag));
+    BOOST_ASSERT(it0.index <= impl_.nparam_);
+    BOOST_ASSERT(pos0 <= impl_.offset(id_frag));
 
     // Iterator is out of range
-    BOOST_ASSERT(it1.index <= u_.nparam_);
-    BOOST_ASSERT(pos1 <= u_.offset(id_frag));
+    BOOST_ASSERT(it1.index <= impl_.nparam_);
+    BOOST_ASSERT(pos1 <= impl_.offset(id_frag));
 
     // calc decoded size of old range,
     // minus one if '?' or '&' prefixed
     auto const dn0 =
         detail::decode_bytes_unchecked(
             string_view(
-                u_.cs_ + pos0,
+                impl_.cs_ + pos0,
                 pos1 - pos0)) - (
-                    u_.len(id_query) > 0);
+                    impl_.len(id_query) > 0);
 
 //------------------------------------------------
 //
@@ -2296,31 +2298,31 @@ edit_params(
             detail::throw_length_error();
         }
         auto const nparam1 =
-            u_.nparam_ + nparam - (
+            impl_.nparam_ + nparam - (
                 it1.index - it0.index);
         reserve_impl(size() + nchar - nremove, op);
         dest = s_ + pos0;
         end = dest + nchar;
-        if(u_.nparam_ > 0)
+        if(impl_.nparam_ > 0)
         {
             // needed when we move
             // the beginning of the query
-            s_[u_.offset(id_query)] = '&';
+            s_[impl_.offset(id_query)] = '&';
         }
         op.move(
             dest + nchar,
-            u_.cs_ + pos1,
+            impl_.cs_ + pos1,
             size() - pos1);
-        u_.set_size(
+        impl_.set_size(
             id_query,
-            u_.len(id_query) +
+            impl_.len(id_query) +
                 nchar - nremove);
-        u_.nparam_ = nparam1;
+        impl_.nparam_ = nparam1;
         if(nparam1 > 0)
         {
             // needed when we erase
             // the beginning of the query
-            s_[u_.offset(id_query)] = '?';
+            s_[impl_.offset(id_query)] = '?';
         }
         if(s_)
             s_[size()] = '\0';
@@ -2354,13 +2356,13 @@ edit_params(
     auto const dn =
         detail::decode_bytes_unchecked(
             string_view(dest0, dest - dest0)) - (
-                u_.len(id_query) > 0);
+                impl_.len(id_query) > 0);
 
-    u_.decoded_[id_query] += (dn - dn0);
+    impl_.decoded_[id_query] += (dn - dn0);
 
     return detail::params_iter_impl(
-        u_,
-        pos0 - u_.offset_[id_query],
+        impl_,
+        pos0 - impl_.offset_[id_query],
         it0.index);
 }
 
@@ -2370,8 +2372,8 @@ void
 url_base::
 decoded_to_lower_impl(int id) noexcept
 {
-    char* it = s_ + u_.offset(id);
-    char const* const end = s_ + u_.offset(id + 1);
+    char* it = s_ + impl_.offset(id);
+    char const* const end = s_ + impl_.offset(id + 1);
     while(it < end)
     {
         if (*it != '%')
@@ -2389,8 +2391,8 @@ void
 url_base::
 to_lower_impl(int id) noexcept
 {
-    char* it = s_ + u_.offset(id);
-    char const* const end = s_ + u_.offset(id + 1);
+    char* it = s_ + impl_.offset(id);
+    char const* const end = s_ + impl_.offset(id + 1);
     while(it < end)
     {
         *it = grammar::to_lower(
diff --git a/include/boost/url/impl/url_view.ipp b/include/boost/url/impl/url_view.ipp
index 482bad7b..c3fdfa6c 100644
--- a/include/boost/url/impl/url_view.ipp
+++ b/include/boost/url/impl/url_view.ipp
@@ -48,8 +48,17 @@ url_view(string_view s)
 url_view::
 url_view(
     url_view_base const& u) noexcept
-    : url_view_base(u.u_)
+    : url_view_base(u.impl_)
 {
+    if (u.pi_->from_ == from::url)
+    {
+        pi_ = u.pi_;
+    }
+    else
+    {
+        impl_ = u.impl_;
+        pi_ = &impl_;
+    }
 }
 
 url_view&
@@ -57,7 +66,15 @@ url_view::
 operator=(
     url_view_base const& u) noexcept
 {
-    u_ = u.u_;
+    if (u.pi_->from_ == from::url)
+    {
+        pi_ = u.pi_;
+    }
+    else
+    {
+        impl_ = u.impl_;
+        pi_ = &impl_;
+    }
     return *this;
 }
 
diff --git a/include/boost/url/impl/url_view_base.ipp b/include/boost/url/impl/url_view_base.ipp
index 02f42bf8..5726765a 100644
--- a/include/boost/url/impl/url_view_base.ipp
+++ b/include/boost/url/impl/url_view_base.ipp
@@ -21,7 +21,8 @@ namespace urls {
 // construct empty view
 url_view_base::
 url_view_base() noexcept
-    : u_(false)
+    : impl_(from::url)
+    , pi_(&impl_)
 {
 }
 
@@ -29,7 +30,8 @@ url_view_base() noexcept
 url_view_base::
 url_view_base(
     detail::url_impl const& impl) noexcept
-    : u_(impl)
+    : impl_(impl)
+    , pi_(&impl_)
 {
 }
 
@@ -40,15 +42,15 @@ url_view_base::
 digest(std::size_t salt) const noexcept
 {
     detail::fnv_1a h(salt);
-    detail::ci_digest(u_.get(id_scheme), h);
-    detail::digest_encoded(u_.get(id_user), h);
-    detail::digest_encoded(u_.get(id_pass), h);
-    detail::ci_digest_encoded(u_.get(id_host), h);
-    h.put(u_.get(id_port));
+    detail::ci_digest(pi_->get(id_scheme), h);
+    detail::digest_encoded(pi_->get(id_user), h);
+    detail::digest_encoded(pi_->get(id_pass), h);
+    detail::ci_digest_encoded(pi_->get(id_host), h);
+    h.put(pi_->get(id_port));
     detail::normalized_path_digest(
-        u_.get(id_path), is_path_absolute(), h);
-    detail::digest_encoded(u_.get(id_query), h);
-    detail::digest_encoded(u_.get(id_frag), h);
+        pi_->get(id_path), is_path_absolute(), h);
+    detail::digest_encoded(pi_->get(id_query), h);
+    detail::digest_encoded(pi_->get(id_frag), h);
     return h.digest();
 }
 
@@ -70,7 +72,7 @@ struct url_view_base::shared_impl
         url_view const& u) noexcept
         : url_view(u)
     {
-        u_.cs_ = reinterpret_cast<
+        impl_.cs_ = reinterpret_cast<
             char const*>(this + 1);
     }
 };
@@ -84,7 +86,7 @@ persist() const
     Alloc a;
     auto p = std::allocate_shared<T>(
         detail::over_allocator<T, Alloc>(
-            size(), a), url_view(u_));
+            size(), a), url_view(*pi_));
     std::memcpy(
         reinterpret_cast<char*>(
             p.get() + 1), data(), size());
@@ -101,13 +103,13 @@ bool
 url_view_base::
 has_scheme() const noexcept
 {
-    auto const n = u_.len(
+    auto const n = pi_->len(
         id_scheme);
     if(n == 0)
         return false;
     BOOST_ASSERT(n > 1);
     BOOST_ASSERT(
-        u_.get(id_scheme
+        pi_->get(id_scheme
             ).ends_with(':'));
     return true;
 }
@@ -116,7 +118,7 @@ string_view
 url_view_base::
 scheme() const noexcept
 {
-    auto s = u_.get(id_scheme);
+    auto s = pi_->get(id_scheme);
     if(! s.empty())
     {
         BOOST_ASSERT(s.size() > 1);
@@ -130,7 +132,7 @@ urls::scheme
 url_view_base::
 scheme_id() const noexcept
 {
-    return u_.scheme_;
+    return pi_->scheme_;
 }
 
 //------------------------------------------------
@@ -143,29 +145,29 @@ authority_view
 url_view_base::
 authority() const noexcept
 {
-    detail::url_impl u(true);
+    detail::url_impl u(from::authority);
     u.cs_ = encoded_authority().data();
     if(has_authority())
     {
-        u.set_size(id_user, u_.len(id_user) - 2);
-        u.set_size(id_pass, u_.len(id_pass));
-        u.set_size(id_host, u_.len(id_host));
-        u.set_size(id_port, u_.len(id_port));
+        u.set_size(id_user, pi_->len(id_user) - 2);
+        u.set_size(id_pass, pi_->len(id_pass));
+        u.set_size(id_host, pi_->len(id_host));
+        u.set_size(id_port, pi_->len(id_port));
     }
     else
     {
-        u.set_size(id_user, u_.len(id_user));
-        BOOST_ASSERT(u_.len(id_pass) == 0);
-        BOOST_ASSERT(u_.len(id_host) == 0);
-        BOOST_ASSERT(u_.len(id_port) == 0);
+        u.set_size(id_user, pi_->len(id_user));
+        BOOST_ASSERT(pi_->len(id_pass) == 0);
+        BOOST_ASSERT(pi_->len(id_host) == 0);
+        BOOST_ASSERT(pi_->len(id_port) == 0);
     }
-    u.decoded_[id_user] = u_.decoded_[id_user];
-    u.decoded_[id_pass] = u_.decoded_[id_pass];
-    u.decoded_[id_host] = u_.decoded_[id_host];
+    u.decoded_[id_user] = pi_->decoded_[id_user];
+    u.decoded_[id_pass] = pi_->decoded_[id_pass];
+    u.decoded_[id_host] = pi_->decoded_[id_host];
     for (int i = 0; i < 16; ++i)
-        u.ip_addr_[i] = u_.ip_addr_[i];
-    u.port_number_ = u_.port_number_;
-    u.host_type_ = u_.host_type_;
+        u.ip_addr_[i] = pi_->ip_addr_[i];
+    u.port_number_ = pi_->port_number_;
+    u.host_type_ = pi_->host_type_;
     return u.construct_authority();
 }
 
@@ -173,7 +175,7 @@ pct_string_view
 url_view_base::
 encoded_authority() const noexcept
 {
-    auto s = u_.get(id_user, id_path);
+    auto s = pi_->get(id_user, id_path);
     if(! s.empty())
     {
         BOOST_ASSERT(has_authority());
@@ -192,11 +194,11 @@ bool
 url_view_base::
 has_userinfo() const noexcept
 {
-    auto n = u_.len(id_pass);
+    auto n = pi_->len(id_pass);
     if(n == 0)
         return false;
     BOOST_ASSERT(has_authority());
-    BOOST_ASSERT(u_.get(
+    BOOST_ASSERT(pi_->get(
         id_pass).ends_with('@'));
     return true;
 }
@@ -205,7 +207,7 @@ pct_string_view
 url_view_base::
 encoded_userinfo() const noexcept
 {
-    auto s = u_.get(
+    auto s = pi_->get(
         id_user, id_host);
     if(s.empty())
         return s;
@@ -218,14 +220,14 @@ encoded_userinfo() const noexcept
         s.ends_with('@'));
     s.remove_suffix(1);
     return detail::make_pct_string_view(
-        s, u_.decoded_[id_user] + u_.decoded_[id_pass] + has_password());
+        s, pi_->decoded_[id_user] + pi_->decoded_[id_pass] + has_password());
 }
 
 pct_string_view
 url_view_base::
 encoded_user() const noexcept
 {
-    auto s = u_.get(id_user);
+    auto s = pi_->get(id_user);
     if(! s.empty())
     {
         BOOST_ASSERT(
@@ -233,23 +235,23 @@ encoded_user() const noexcept
         s.remove_prefix(2);
     }
     return detail::make_pct_string_view(
-        s, u_.decoded_[id_user]);
+        s, pi_->decoded_[id_user]);
 }
 
 bool
 url_view_base::
 has_password() const noexcept
 {
-    auto const n = u_.len(id_pass);
+    auto const n = pi_->len(id_pass);
     if(n > 1)
     {
-        BOOST_ASSERT(u_.get(id_pass
+        BOOST_ASSERT(pi_->get(id_pass
             ).starts_with(':'));
-        BOOST_ASSERT(u_.get(id_pass
+        BOOST_ASSERT(pi_->get(id_pass
             ).ends_with('@'));
         return true;
     }
-    BOOST_ASSERT(n == 0 || u_.get(
+    BOOST_ASSERT(n == 0 || pi_->get(
         id_pass).ends_with('@'));
     return false;
 }
@@ -258,7 +260,7 @@ pct_string_view
 url_view_base::
 encoded_password() const noexcept
 {
-    auto s = u_.get(id_pass);
+    auto s = pi_->get(id_pass);
     switch(s.size())
     {
     case 1:
@@ -275,7 +277,7 @@ encoded_password() const noexcept
     BOOST_ASSERT(s.starts_with(':'));
     return detail::make_pct_string_view(
         s.substr(1, s.size() - 2),
-        u_.decoded_[id_pass]);
+        pi_->decoded_[id_pass]);
 }
 
 //------------------------------------------------
@@ -303,17 +305,17 @@ url_view_base::
 encoded_host() const noexcept
 {
     return detail::make_pct_string_view(
-        u_.get(id_host),
-        u_.decoded_[id_host]);
+        pi_->get(id_host),
+        pi_->decoded_[id_host]);
 }
 
 pct_string_view
 url_view_base::
 encoded_host_address() const noexcept
 {
-    string_view s = u_.get(id_host);
+    string_view s = pi_->get(id_host);
     std::size_t n;
-    switch(u_.host_type_)
+    switch(pi_->host_type_)
     {
     default:
     case urls::host_type::none:
@@ -323,20 +325,20 @@ encoded_host_address() const noexcept
 
     case urls::host_type::name:
     case urls::host_type::ipv4:
-        n = u_.decoded_[id_host];
+        n = pi_->decoded_[id_host];
         break;
 
     case urls::host_type::ipv6:
     case urls::host_type::ipvfuture:
     {
         BOOST_ASSERT(
-            u_.decoded_[id_host] ==
+            pi_->decoded_[id_host] ==
                 s.size());
         BOOST_ASSERT(s.size() >= 2);
         BOOST_ASSERT(s.front() == '[');
         BOOST_ASSERT(s.back() == ']');
         s = s.substr(1, s.size() - 2);
-        n = u_.decoded_[id_host] - 2;
+        n = pi_->decoded_[id_host] - 2;
         break;
     }
     }
@@ -347,12 +349,12 @@ urls::ipv4_address
 url_view_base::
 host_ipv4_address() const noexcept
 {
-    if(u_.host_type_ !=
+    if(pi_->host_type_ !=
             urls::host_type::ipv4)
         return {};
     ipv4_address::bytes_type b;
     std::memcpy(
-        &b[0], &u_.ip_addr_[0], b.size());
+        &b[0], &pi_->ip_addr_[0], b.size());
     return urls::ipv4_address(b);
 }
 
@@ -360,12 +362,12 @@ urls::ipv6_address
 url_view_base::
 host_ipv6_address() const noexcept
 {
-    if(u_.host_type_ !=
+    if(pi_->host_type_ !=
             urls::host_type::ipv6)
         return {};
     ipv6_address::bytes_type b;
     std::memcpy(
-        &b[0], &u_.ip_addr_[0], b.size());
+        &b[0], &pi_->ip_addr_[0], b.size());
     return urls::ipv6_address(b);
 }
 
@@ -373,10 +375,10 @@ string_view
 url_view_base::
 host_ipvfuture() const noexcept
 {
-    if(u_.host_type_ !=
+    if(pi_->host_type_ !=
             urls::host_type::ipvfuture)
         return {};
-    string_view s = u_.get(id_host);
+    string_view s = pi_->get(id_host);
     BOOST_ASSERT(s.size() >= 6);
     BOOST_ASSERT(s.front() == '[');
     BOOST_ASSERT(s.back() == ']');
@@ -388,12 +390,12 @@ pct_string_view
 url_view_base::
 encoded_host_name() const noexcept
 {
-    if(u_.host_type_ !=
+    if(pi_->host_type_ !=
             urls::host_type::name)
         return {};
-    string_view s = u_.get(id_host);
+    string_view s = pi_->get(id_host);
     return detail::make_pct_string_view(
-        s, u_.decoded_[id_host]);
+        s, pi_->decoded_[id_host]);
 }
 
 //------------------------------------------------
@@ -402,11 +404,11 @@ bool
 url_view_base::
 has_port() const noexcept
 {
-    auto const n = u_.len(id_port);
+    auto const n = pi_->len(id_port);
     if(n == 0)
         return false;
     BOOST_ASSERT(
-        u_.get(id_port).starts_with(':'));
+        pi_->get(id_port).starts_with(':'));
     return true;
 }
 
@@ -414,7 +416,7 @@ string_view
 url_view_base::
 port() const noexcept
 {
-    auto s = u_.get(id_port);
+    auto s = pi_->get(id_port);
     if(s.empty())
         return s;
     BOOST_ASSERT(has_port());
@@ -427,8 +429,8 @@ port_number() const noexcept
 {
     BOOST_ASSERT(
         has_port() ||
-        u_.port_number_ == 0);
-    return u_.port_number_;
+        pi_->port_number_ == 0);
+    return pi_->port_number_;
 }
 
 //------------------------------------------------
@@ -438,16 +440,16 @@ url_view_base::
 encoded_host_and_port() const noexcept
 {
     return detail::make_pct_string_view(
-        u_.get(id_host, id_path));
+        pi_->get(id_host, id_path));
 }
 
 pct_string_view
 url_view_base::
 encoded_origin() const noexcept
 {
-    if(u_.len(id_user) < 2)
+    if(pi_->len(id_user) < 2)
         return {};
-    return u_.get(id_scheme, id_path);
+    return pi_->get(id_scheme, id_path);
 }
 
 //------------------------------------------------
@@ -461,14 +463,14 @@ url_view_base::
 encoded_path() const noexcept
 {
     return detail::make_pct_string_view(
-        u_.get(id_path), u_.decoded_[id_path]);
+        pi_->get(id_path), pi_->decoded_[id_path]);
 }
 
 segments_view
 url_view_base::
 segments() const noexcept
 {
-    return {detail::path_ref(u_)};
+    return {detail::path_ref(*pi_)};
 }
 
 segments_encoded_view
@@ -476,7 +478,7 @@ url_view_base::
 encoded_segments() const noexcept
 {
     return segments_encoded_view(
-        detail::path_ref(u_));
+        detail::path_ref(*pi_));
 }
 
 //------------------------------------------------
@@ -489,12 +491,12 @@ bool
 url_view_base::
 has_query() const noexcept
 {
-    auto const n = u_.len(
+    auto const n = pi_->len(
         id_query);
     if(n == 0)
         return false;
     BOOST_ASSERT(
-        u_.get(id_query).
+        pi_->get(id_query).
             starts_with('?'));
     return true;
 }
@@ -503,7 +505,7 @@ pct_string_view
 url_view_base::
 encoded_query() const noexcept
 {
-    auto s = u_.get(id_query);
+    auto s = pi_->get(id_query);
     if(s.empty())
         return s;
     BOOST_ASSERT(
@@ -515,14 +517,14 @@ params_encoded_view
 url_view_base::
 encoded_params() const noexcept
 {
-    return params_encoded_view(u_);
+    return params_encoded_view(*pi_);
 }
 
 params_view
 url_view_base::
 params() const noexcept
 {
-    return params_view(u_);
+    return params_view(*pi_);
 }
 
 //------------------------------------------------
@@ -532,15 +534,15 @@ url_view_base::
 encoded_target() const noexcept
 {
     auto n =
-        u_.decoded_[id_path] +
-        u_.decoded_[id_query];
+        pi_->decoded_[id_path] +
+        pi_->decoded_[id_query];
     if(has_query())
         ++n;
     BOOST_ASSERT(pct_string_view(
-        u_.get(id_path, id_frag)
+        pi_->get(id_path, id_frag)
             ).decoded_size() == n);
     return detail::make_pct_string_view(
-        u_.get(id_path, id_frag), n);
+        pi_->get(id_path, id_frag), n);
 }
 
 //------------------------------------------------
@@ -553,11 +555,11 @@ bool
 url_view_base::
 has_fragment() const noexcept
 {
-    auto const n = u_.len(id_frag);
+    auto const n = pi_->len(id_frag);
     if(n == 0)
         return false;
     BOOST_ASSERT(
-        u_.get(id_frag).
+        pi_->get(id_frag).
             starts_with('#'));
     return true;
 }
@@ -566,7 +568,7 @@ pct_string_view
 url_view_base::
 encoded_fragment() const noexcept
 {
-    auto s = u_.get(id_frag);
+    auto s = pi_->get(id_frag);
     if(! s.empty())
     {
         BOOST_ASSERT(
@@ -574,7 +576,7 @@ encoded_fragment() const noexcept
         s.remove_prefix(1);
     }
     return detail::make_pct_string_view(
-        s, u_.decoded_[id_frag]);
+        s, pi_->decoded_[id_frag]);
 }
 
 //------------------------------------------------
@@ -584,18 +586,18 @@ url_view_base::
 encoded_resource() const noexcept
 {
     auto n =
-        u_.decoded_[id_path] +
-        u_.decoded_[id_query] +
-        u_.decoded_[id_frag];
+        pi_->decoded_[id_path] +
+        pi_->decoded_[id_query] +
+        pi_->decoded_[id_frag];
     if(has_query())
         ++n;
     if(has_fragment())
         ++n;
     BOOST_ASSERT(pct_string_view(
-        u_.get(id_path, id_end)
+        pi_->get(id_path, id_end)
             ).decoded_size() == n);
     return detail::make_pct_string_view(
-        u_.get(id_path, id_end), n);
+        pi_->get(id_path, id_end), n);
 }
 
 //------------------------------------------------
diff --git a/include/boost/url/rfc/impl/absolute_uri_rule.ipp b/include/boost/url/rfc/impl/absolute_uri_rule.ipp
index 7a3bbd01..660f9562 100644
--- a/include/boost/url/rfc/impl/absolute_uri_rule.ipp
+++ b/include/boost/url/rfc/impl/absolute_uri_rule.ipp
@@ -31,7 +31,7 @@ parse(
         ) const noexcept ->
     result<value_type>
 {
-    detail::url_impl u(false);
+    detail::url_impl u(detail::url_impl::from::string);
     u.cs_ = it;
 
     // scheme
diff --git a/include/boost/url/rfc/impl/authority_rule.ipp b/include/boost/url/rfc/impl/authority_rule.ipp
index 6a1fd0dd..ee9e977b 100644
--- a/include/boost/url/rfc/impl/authority_rule.ipp
+++ b/include/boost/url/rfc/impl/authority_rule.ipp
@@ -29,7 +29,7 @@ parse(
         ) const noexcept ->
     result<value_type>
 {
-    detail::url_impl u(true);
+    detail::url_impl u(detail::url_impl::from::authority);
     u.cs_ = it;
 
     // [ userinfo "@" ]
diff --git a/include/boost/url/rfc/impl/origin_form_rule.ipp b/include/boost/url/rfc/impl/origin_form_rule.ipp
index f66226aa..211afcc8 100644
--- a/include/boost/url/rfc/impl/origin_form_rule.ipp
+++ b/include/boost/url/rfc/impl/origin_form_rule.ipp
@@ -28,7 +28,7 @@ parse(
         ) const noexcept ->
     result<value_type>
 {
-    detail::url_impl u(false);
+    detail::url_impl u(detail::url_impl::from::string);
     u.cs_ = it;
 
     {
diff --git a/include/boost/url/rfc/impl/relative_ref_rule.ipp b/include/boost/url/rfc/impl/relative_ref_rule.ipp
index 52f37684..c3437513 100644
--- a/include/boost/url/rfc/impl/relative_ref_rule.ipp
+++ b/include/boost/url/rfc/impl/relative_ref_rule.ipp
@@ -30,7 +30,7 @@ parse(
         ) const noexcept ->
     result<value_type>
 {
-    detail::url_impl u(false);
+    detail::url_impl u(detail::url_impl::from::string);
     u.cs_ = it;
 
     // relative-part
diff --git a/include/boost/url/rfc/impl/uri_rule.ipp b/include/boost/url/rfc/impl/uri_rule.ipp
index 5e7a0a62..f1b36320 100644
--- a/include/boost/url/rfc/impl/uri_rule.ipp
+++ b/include/boost/url/rfc/impl/uri_rule.ipp
@@ -31,7 +31,7 @@ parse(
         ) const noexcept ->
     result<value_type>
 {
-    detail::url_impl u(false);
+    detail::url_impl u(detail::url_impl::from::string);
     u.cs_ = it;
 
     // scheme
diff --git a/include/boost/url/url_base.hpp b/include/boost/url/url_base.hpp
index 55a9f1ba..0e11758e 100644
--- a/include/boost/url/url_base.hpp
+++ b/include/boost/url/url_base.hpp
@@ -124,7 +124,7 @@ public:
     char const*
     c_str() const noexcept
     {
-        return u_.cs_;
+        return pi_->cs_;
     }
 
     /** Return the number of characters that can be stored without reallocating
diff --git a/include/boost/url/url_view_base.hpp b/include/boost/url/url_view_base.hpp
index 72b9a733..9daa187b 100644
--- a/include/boost/url/url_view_base.hpp
+++ b/include/boost/url/url_view_base.hpp
@@ -59,7 +59,8 @@ class BOOST_SYMBOL_VISIBLE
     url_view_base
     : private detail::parts_base
 {
-    detail::url_impl u_;
+    detail::url_impl impl_;
+    detail::url_impl const* pi_;
 
     friend class url;
     friend class url_base;
@@ -82,12 +83,22 @@ class BOOST_SYMBOL_VISIBLE
 
     BOOST_URL_DECL
     url_view_base() noexcept;
+
     BOOST_URL_DECL
     explicit url_view_base(
         detail::url_impl const&) noexcept;
+
     ~url_view_base() = default;
+
     url_view_base(
-        url_view_base const&) = default;
+        url_view_base const& o) noexcept
+        : impl_(o.impl_)
+        , pi_(o.pi_)
+    {
+        if (pi_ == &o.impl_)
+            pi_ = &impl_;
+    }
+
     url_view_base& operator=(
         url_view_base const&) = delete;
 
@@ -149,7 +160,7 @@ public:
     std::size_t
     size() const noexcept
     {
-        return u_.offset(id_end);
+        return pi_->offset(id_end);
     }
 
     /** Return true if the URL is empty
@@ -185,7 +196,7 @@ public:
     bool
     empty() const noexcept
     {
-        return u_.offset(id_end) == 0;
+        return pi_->offset(id_end) == 0;
     }
 
     /** Return a pointer to the URL's character buffer
@@ -203,7 +214,7 @@ public:
     char const*
     data() const noexcept
     {
-        return u_.cs_;
+        return pi_->cs_;
     }
 
     /** Return the URL string
@@ -454,7 +465,7 @@ public:
     bool
     has_authority() const noexcept
     {
-        return u_.len(id_user) > 0;
+        return pi_->len(id_user) > 0;
     }
 
     /** Return the authority
@@ -956,7 +967,7 @@ public:
     urls::host_type
     host_type() const noexcept
     {
-        return u_.host_type_;
+        return pi_->host_type_;
     }
 
     /** Return the host
@@ -1593,8 +1604,8 @@ public:
     is_path_absolute() const noexcept
     {
         return
-            u_.len(id_path) > 0 &&
-            u_.cs_[u_.offset(id_path)] == '/';
+            pi_->len(id_path) > 0 &&
+            pi_->cs_[pi_->offset(id_path)] == '/';
     }
 
     /** Return the path