diff --git a/include/ndnboost/regex/v4/regbase.hpp b/include/ndnboost/regex/v4/regbase.hpp
new file mode 100644
index 0000000..7c52468
--- /dev/null
+++ b/include/ndnboost/regex/v4/regbase.hpp
@@ -0,0 +1,180 @@
+/*
+ *
+ * Copyright (c) 1998-2002
+ * John Maddock
+ *
+ * Use, modification and distribution are subject to the 
+ * Boost Software License, Version 1.0. (See accompanying file 
+ * LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+ *
+ */
+
+ /*
+  *   LOCATION:    see http://www.boost.org for most recent version.
+  *   FILE         regbase.cpp
+  *   VERSION      see <ndnboost/version.hpp>
+  *   DESCRIPTION: Declares class regbase.
+  */
+
+#ifndef NDNBOOST_REGEX_V4_REGBASE_HPP
+#define NDNBOOST_REGEX_V4_REGBASE_HPP
+
+#ifdef NDNBOOST_MSVC
+#pragma warning(push)
+#pragma warning(disable: 4103)
+#endif
+#ifdef NDNBOOST_HAS_ABI_HEADERS
+#  include NDNBOOST_ABI_PREFIX
+#endif
+#ifdef NDNBOOST_MSVC
+#pragma warning(pop)
+#endif
+
+namespace ndnboost{
+//
+// class regbase
+// handles error codes and flags
+//
+class NDNBOOST_REGEX_DECL regbase
+{
+public:
+   enum flag_type_
+   {
+      //
+      // Divide the flags up into logical groups:
+      // bits 0-7 indicate main synatx type.
+      // bits 8-15 indicate syntax subtype.
+      // bits 16-31 indicate options that are common to all
+      // regex syntaxes.
+      // In all cases the default is 0.
+      //
+      // Main synatx group:
+      //
+      perl_syntax_group = 0,                      // default
+      basic_syntax_group = 1,                     // POSIX basic
+      literal = 2,                                // all characters are literals
+      main_option_type = literal | basic_syntax_group | perl_syntax_group, // everything!
+      //
+      // options specific to perl group:
+      //
+      no_bk_refs = 1 << 8,                        // \d not allowed
+      no_perl_ex = 1 << 9,                        // disable perl extensions
+      no_mod_m = 1 << 10,                         // disable Perl m modifier
+      mod_x = 1 << 11,                            // Perl x modifier
+      mod_s = 1 << 12,                            // force s modifier on (overrides match_not_dot_newline)
+      no_mod_s = 1 << 13,                         // force s modifier off (overrides match_not_dot_newline)
+
+      //
+      // options specific to basic group:
+      //
+      no_char_classes = 1 << 8,                   // [[:CLASS:]] not allowed
+      no_intervals = 1 << 9,                      // {x,y} not allowed
+      bk_plus_qm = 1 << 10,                       // uses \+ and \?
+      bk_vbar = 1 << 11,                          // use \| for alternatives
+      emacs_ex = 1 << 12,                         // enables emacs extensions
+
+      //
+      // options common to all groups:
+      //
+      no_escape_in_lists = 1 << 16,                     // '\' not special inside [...]
+      newline_alt = 1 << 17,                            // \n is the same as |
+      no_except = 1 << 18,                              // no exception on error
+      failbit = 1 << 19,                                // error flag
+      icase = 1 << 20,                                  // characters are matched regardless of case
+      nocollate = 0,                                    // don't use locale specific collation (deprecated)
+      collate = 1 << 21,                                // use locale specific collation
+      nosubs = 1 << 22,                                 // don't mark sub-expressions
+      save_subexpression_location = 1 << 23,            // save subexpression locations
+      no_empty_expressions = 1 << 24,                   // no empty expressions allowed
+      optimize = 0,                                     // not really supported
+      
+
+
+      basic = basic_syntax_group | collate | no_escape_in_lists,
+      extended = no_bk_refs | collate | no_perl_ex | no_escape_in_lists,
+      normal = 0,
+      emacs = basic_syntax_group | collate | emacs_ex | bk_vbar,
+      awk = no_bk_refs | collate | no_perl_ex,
+      grep = basic | newline_alt,
+      egrep = extended | newline_alt,
+      sed = basic,
+      perl = normal,
+      ECMAScript = normal,
+      JavaScript = normal,
+      JScript = normal
+   };
+   typedef unsigned int flag_type;
+
+   enum restart_info
+   {
+      restart_any = 0,
+      restart_word = 1,
+      restart_line = 2,
+      restart_buf = 3,
+      restart_continue = 4,
+      restart_lit = 5,
+      restart_fixed_lit = 6, 
+      restart_count = 7
+   };
+};
+
+//
+// provide std lib proposal compatible constants:
+//
+namespace regex_constants{
+
+   enum flag_type_
+   {
+
+      no_except = ::ndnboost::regbase::no_except,
+      failbit = ::ndnboost::regbase::failbit,
+      literal = ::ndnboost::regbase::literal,
+      icase = ::ndnboost::regbase::icase,
+      nocollate = ::ndnboost::regbase::nocollate,
+      collate = ::ndnboost::regbase::collate,
+      nosubs = ::ndnboost::regbase::nosubs,
+      optimize = ::ndnboost::regbase::optimize,
+      bk_plus_qm = ::ndnboost::regbase::bk_plus_qm,
+      bk_vbar = ::ndnboost::regbase::bk_vbar,
+      no_intervals = ::ndnboost::regbase::no_intervals,
+      no_char_classes = ::ndnboost::regbase::no_char_classes,
+      no_escape_in_lists = ::ndnboost::regbase::no_escape_in_lists,
+      no_mod_m = ::ndnboost::regbase::no_mod_m,
+      mod_x = ::ndnboost::regbase::mod_x,
+      mod_s = ::ndnboost::regbase::mod_s,
+      no_mod_s = ::ndnboost::regbase::no_mod_s,
+      save_subexpression_location = ::ndnboost::regbase::save_subexpression_location,
+      no_empty_expressions = ::ndnboost::regbase::no_empty_expressions,
+
+      basic = ::ndnboost::regbase::basic,
+      extended = ::ndnboost::regbase::extended,
+      normal = ::ndnboost::regbase::normal,
+      emacs = ::ndnboost::regbase::emacs,
+      awk = ::ndnboost::regbase::awk,
+      grep = ::ndnboost::regbase::grep,
+      egrep = ::ndnboost::regbase::egrep,
+      sed = basic,
+      perl = normal,
+      ECMAScript = normal,
+      JavaScript = normal,
+      JScript = normal
+   };
+   typedef ::ndnboost::regbase::flag_type syntax_option_type;
+
+} // namespace regex_constants
+
+} // namespace ndnboost
+
+#ifdef NDNBOOST_MSVC
+#pragma warning(push)
+#pragma warning(disable: 4103)
+#endif
+#ifdef NDNBOOST_HAS_ABI_HEADERS
+#  include NDNBOOST_ABI_SUFFIX
+#endif
+#ifdef NDNBOOST_MSVC
+#pragma warning(pop)
+#endif
+
+#endif
+