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- // 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
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