Chris@16: //  boost cast.hpp header file  ----------------------------------------------//
Chris@16: 
Chris@16: //  (C) Copyright Kevlin Henney and Dave Abrahams 1999.
Chris@16: //  Distributed under the Boost
Chris@16: //  Software License, Version 1.0. (See accompanying file
Chris@16: //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: //  See http://www.boost.org/libs/conversion for Documentation.
Chris@16: 
Chris@16: //  Revision History
Chris@16: //  23 JUn 05  numeric_cast removed and redirected to the new verion (Fernando Cacciola)
Chris@16: //  02 Apr 01  Removed BOOST_NO_LIMITS workarounds and included
Chris@16: //             <boost/limits.hpp> instead (the workaround did not
Chris@16: //             actually compile when BOOST_NO_LIMITS was defined in
Chris@16: //             any case, so we loose nothing). (John Maddock)
Chris@16: //  21 Jan 01  Undid a bug I introduced yesterday. numeric_cast<> never
Chris@16: //             worked with stock GCC; trying to get it to do that broke
Chris@16: //             vc-stlport.
Chris@16: //  20 Jan 01  Moved BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS to config.hpp.
Chris@16: //             Removed unused BOOST_EXPLICIT_TARGET macro. Moved
Chris@16: //             boost::detail::type to boost/type.hpp. Made it compile with
Chris@16: //             stock gcc again (Dave Abrahams)
Chris@16: //  29 Nov 00  Remove nested namespace cast, cleanup spacing before Formal
Chris@16: //             Review (Beman Dawes)
Chris@16: //  19 Oct 00  Fix numeric_cast for floating-point types (Dave Abrahams)
Chris@16: //  15 Jul 00  Suppress numeric_cast warnings for GCC, Borland and MSVC
Chris@16: //             (Dave Abrahams)
Chris@16: //  30 Jun 00  More MSVC6 wordarounds.  See comments below.  (Dave Abrahams)
Chris@16: //  28 Jun 00  Removed implicit_cast<>.  See comment below. (Beman Dawes)
Chris@16: //  27 Jun 00  More MSVC6 workarounds
Chris@16: //  15 Jun 00  Add workarounds for MSVC6
Chris@16: //   2 Feb 00  Remove bad_numeric_cast ";" syntax error (Doncho Angelov)
Chris@16: //  26 Jan 00  Add missing throw() to bad_numeric_cast::what(0 (Adam Levar)
Chris@16: //  29 Dec 99  Change using declarations so usages in other namespaces work
Chris@16: //             correctly (Dave Abrahams)
Chris@16: //  23 Sep 99  Change polymorphic_downcast assert to also detect M.I. errors
Chris@16: //             as suggested Darin Adler and improved by Valentin Bonnard.
Chris@16: //   2 Sep 99  Remove controversial asserts, simplify, rename.
Chris@16: //  30 Aug 99  Move to cast.hpp, replace value_cast with numeric_cast,
Chris@16: //             place in nested namespace.
Chris@16: //   3 Aug 99  Initial version
Chris@16: 
Chris@16: #ifndef BOOST_CAST_HPP
Chris@16: #define BOOST_CAST_HPP
Chris@16: 
Chris@16: # include <boost/config.hpp>
Chris@16: # include <boost/assert.hpp>
Chris@16: # include <typeinfo>
Chris@16: # include <boost/type.hpp>
Chris@16: # include <boost/limits.hpp>
Chris@16: # include <boost/detail/select_type.hpp>
Chris@16: 
Chris@16: //  It has been demonstrated numerous times that MSVC 6.0 fails silently at link
Chris@16: //  time if you use a template function which has template parameters that don't
Chris@16: //  appear in the function's argument list.
Chris@16: //
Chris@16: //  TODO: Add this to config.hpp?
Chris@16: # if defined(BOOST_MSVC) && BOOST_MSVC < 1300
Chris@16: #  define BOOST_EXPLICIT_DEFAULT_TARGET , ::boost::type<Target>* = 0
Chris@16: # else
Chris@16: #  define BOOST_EXPLICIT_DEFAULT_TARGET
Chris@16: # endif
Chris@16: 
Chris@16: namespace boost
Chris@16: {
Chris@16: //  See the documentation for descriptions of how to choose between
Chris@16: //  static_cast<>, dynamic_cast<>, polymorphic_cast<> and polymorphic_downcast<>
Chris@16: 
Chris@16: //  polymorphic_cast  --------------------------------------------------------//
Chris@16: 
Chris@16:     //  Runtime checked polymorphic downcasts and crosscasts.
Chris@16:     //  Suggested in The C++ Programming Language, 3rd Ed, Bjarne Stroustrup,
Chris@16:     //  section 15.8 exercise 1, page 425.
Chris@16: 
Chris@16:     template <class Target, class Source>
Chris@16:     inline Target polymorphic_cast(Source* x BOOST_EXPLICIT_DEFAULT_TARGET)
Chris@16:     {
Chris@16:         Target tmp = dynamic_cast<Target>(x);
Chris@16:         if ( tmp == 0 ) throw std::bad_cast();
Chris@16:         return tmp;
Chris@16:     }
Chris@16: 
Chris@16: //  polymorphic_downcast  ----------------------------------------------------//
Chris@16: 
Chris@16:     //  BOOST_ASSERT() checked polymorphic downcast.  Crosscasts prohibited.
Chris@16: 
Chris@16:     //  WARNING: Because this cast uses BOOST_ASSERT(), it violates
Chris@16:     //  the One Definition Rule if used in multiple translation units
Chris@16:     //  where BOOST_DISABLE_ASSERTS, BOOST_ENABLE_ASSERT_HANDLER
Chris@16:     //  NDEBUG are defined inconsistently.
Chris@16: 
Chris@16:     //  Contributed by Dave Abrahams
Chris@16: 
Chris@16:     template <class Target, class Source>
Chris@16:     inline Target polymorphic_downcast(Source* x BOOST_EXPLICIT_DEFAULT_TARGET)
Chris@16:     {
Chris@16:         BOOST_ASSERT( dynamic_cast<Target>(x) == x );  // detect logic error
Chris@16:         return static_cast<Target>(x);
Chris@16:     }
Chris@16: 
Chris@16: #  undef BOOST_EXPLICIT_DEFAULT_TARGET
Chris@16: 
Chris@16: } // namespace boost
Chris@16: 
Chris@16: # include <boost/numeric/conversion/cast.hpp>
Chris@16: 
Chris@16: #endif  // BOOST_CAST_HPP