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