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309 lines
11 KiB
C++
309 lines
11 KiB
C++
// boost cast.hpp header file ----------------------------------------------//
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// (C) Copyright Kevlin Henney and Dave Abrahams 1999.
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// Distributed under the Boost
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// Software License, Version 1.0. (See accompanying file
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// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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// See http://www.boost.org/libs/conversion for Documentation.
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// Revision History
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// 02 Jun 14 Remove VC6 workarounds.
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// 16 Jul 11 Bugfixes for VC6.
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// 23 JUN 05 Code extracted from /boost/cast.hpp into this new header.
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// Keeps this legacy version of numeric_cast<> for old compilers
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// wich can't compile the new version in /boost/numeric/conversion/cast.hpp
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// (Fernando Cacciola)
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// 02 Apr 01 Removed BOOST_NO_LIMITS workarounds and included
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// <boost/limits.hpp> instead (the workaround did not
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// actually compile when BOOST_NO_LIMITS was defined in
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// any case, so we loose nothing). (John Maddock)
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// 21 Jan 01 Undid a bug I introduced yesterday. numeric_cast<> never
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// worked with stock GCC; trying to get it to do that broke
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// vc-stlport.
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// 20 Jan 01 Moved BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS to config.hpp.
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// Removed unused BOOST_EXPLICIT_TARGET macro. Moved
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// boost::detail::type to boost/type.hpp. Made it compile with
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// stock gcc again (Dave Abrahams)
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// 29 Nov 00 Remove nested namespace cast, cleanup spacing before Formal
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// Review (Beman Dawes)
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// 19 Oct 00 Fix numeric_cast for floating-point types (Dave Abrahams)
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// 15 Jul 00 Suppress numeric_cast warnings for GCC, Borland and MSVC
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// (Dave Abrahams)
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// 30 Jun 00 More MSVC6 wordarounds. See comments below. (Dave Abrahams)
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// 28 Jun 00 Removed implicit_cast<>. See comment below. (Beman Dawes)
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// 27 Jun 00 More MSVC6 workarounds
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// 15 Jun 00 Add workarounds for MSVC6
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// 2 Feb 00 Remove bad_numeric_cast ";" syntax error (Doncho Angelov)
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// 26 Jan 00 Add missing throw() to bad_numeric_cast::what(0 (Adam Levar)
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// 29 Dec 99 Change using declarations so usages in other namespaces work
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// correctly (Dave Abrahams)
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// 23 Sep 99 Change polymorphic_downcast assert to also detect M.I. errors
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// as suggested Darin Adler and improved by Valentin Bonnard.
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// 2 Sep 99 Remove controversial asserts, simplify, rename.
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// 30 Aug 99 Move to cast.hpp, replace value_cast with numeric_cast,
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// place in nested namespace.
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// 3 Aug 99 Initial version
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#ifndef BOOST_OLD_NUMERIC_CAST_HPP
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#define BOOST_OLD_NUMERIC_CAST_HPP
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# include <boost/config.hpp>
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# include <cassert>
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# include <typeinfo>
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# include <boost/type.hpp>
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# include <boost/limits.hpp>
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# include <boost/numeric/conversion/converter_policies.hpp>
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namespace boost
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{
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using numeric::bad_numeric_cast;
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// LEGACY numeric_cast [only for some old broken compilers] --------------------------------------//
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// Contributed by Kevlin Henney
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// numeric_cast ------------------------------------------------------------//
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#if !defined(BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS) || defined(BOOST_SGI_CPP_LIMITS)
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namespace detail
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{
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template <class T>
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struct signed_numeric_limits : std::numeric_limits<T>
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{
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static inline T min BOOST_PREVENT_MACRO_SUBSTITUTION ()
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{
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return (std::numeric_limits<T>::min)() >= 0
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// unary minus causes integral promotion, thus the static_cast<>
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? static_cast<T>(-(std::numeric_limits<T>::max)())
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: (std::numeric_limits<T>::min)();
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};
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};
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// Move to namespace boost in utility.hpp?
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template <class T, bool specialized>
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struct fixed_numeric_limits_base
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: public if_true< std::numeric_limits<T>::is_signed >
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::BOOST_NESTED_TEMPLATE then< signed_numeric_limits<T>,
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std::numeric_limits<T>
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>::type
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{};
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template <class T>
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struct fixed_numeric_limits
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: fixed_numeric_limits_base<T,(std::numeric_limits<T>::is_specialized)>
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{};
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# ifdef BOOST_HAS_LONG_LONG
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// cover implementations which supply no specialization for long
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// long / unsigned long long. Not intended to be full
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// numeric_limits replacements, but good enough for numeric_cast<>
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template <>
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struct fixed_numeric_limits_base< ::boost::long_long_type, false>
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{
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BOOST_STATIC_CONSTANT(bool, is_specialized = true);
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BOOST_STATIC_CONSTANT(bool, is_signed = true);
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static ::boost::long_long_type max BOOST_PREVENT_MACRO_SUBSTITUTION ()
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{
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# ifdef LONGLONG_MAX
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return LONGLONG_MAX;
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# else
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return 9223372036854775807LL; // hope this is portable
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# endif
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}
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static ::boost::long_long_type min BOOST_PREVENT_MACRO_SUBSTITUTION ()
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{
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# ifdef LONGLONG_MIN
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return LONGLONG_MIN;
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# else
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return -( 9223372036854775807LL )-1; // hope this is portable
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# endif
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}
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};
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template <>
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struct fixed_numeric_limits_base< ::boost::ulong_long_type, false>
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{
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BOOST_STATIC_CONSTANT(bool, is_specialized = true);
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BOOST_STATIC_CONSTANT(bool, is_signed = false);
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static ::boost::ulong_long_type max BOOST_PREVENT_MACRO_SUBSTITUTION ()
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{
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# ifdef ULONGLONG_MAX
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return ULONGLONG_MAX;
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# else
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return 0xffffffffffffffffULL; // hope this is portable
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# endif
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}
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static ::boost::ulong_long_type min BOOST_PREVENT_MACRO_SUBSTITUTION () { return 0; }
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};
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# endif
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} // namespace detail
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// less_than_type_min -
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// x_is_signed should be numeric_limits<X>::is_signed
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// y_is_signed should be numeric_limits<Y>::is_signed
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// y_min should be numeric_limits<Y>::min()
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//
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// check(x, y_min) returns true iff x < y_min without invoking comparisons
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// between signed and unsigned values.
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//
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// "poor man's partial specialization" is in use here.
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template <bool x_is_signed, bool y_is_signed>
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struct less_than_type_min
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{
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template <class X, class Y>
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static bool check(X x, Y y_min)
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{ return x < y_min; }
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};
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template <>
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struct less_than_type_min<false, true>
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{
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template <class X, class Y>
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static bool check(X, Y)
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{ return false; }
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};
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template <>
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struct less_than_type_min<true, false>
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{
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template <class X, class Y>
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static bool check(X x, Y)
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{ return x < 0; }
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};
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// greater_than_type_max -
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// same_sign should be:
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// numeric_limits<X>::is_signed == numeric_limits<Y>::is_signed
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// y_max should be numeric_limits<Y>::max()
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//
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// check(x, y_max) returns true iff x > y_max without invoking comparisons
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// between signed and unsigned values.
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//
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// "poor man's partial specialization" is in use here.
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template <bool same_sign, bool x_is_signed>
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struct greater_than_type_max;
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template<>
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struct greater_than_type_max<true, true>
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{
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template <class X, class Y>
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static inline bool check(X x, Y y_max)
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{ return x > y_max; }
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};
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template <>
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struct greater_than_type_max<false, true>
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{
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// What does the standard say about this? I think it's right, and it
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// will work with every compiler I know of.
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template <class X, class Y>
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static inline bool check(X x, Y)
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{ return x >= 0 && static_cast<X>(static_cast<Y>(x)) != x; }
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};
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template<>
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struct greater_than_type_max<true, false>
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{
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template <class X, class Y>
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static inline bool check(X x, Y y_max)
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{ return x > y_max; }
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};
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template <>
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struct greater_than_type_max<false, false>
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{
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// What does the standard say about this? I think it's right, and it
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// will work with every compiler I know of.
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template <class X, class Y>
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static inline bool check(X x, Y)
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{ return static_cast<X>(static_cast<Y>(x)) != x; }
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};
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#else // use #pragma hacks if available
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namespace detail
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{
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# if BOOST_MSVC
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# pragma warning(push)
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# pragma warning(disable : 4018)
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# pragma warning(disable : 4146)
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#elif defined(__BORLANDC__)
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# pragma option push -w-8041
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# endif
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// Move to namespace boost in utility.hpp?
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template <class T>
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struct fixed_numeric_limits : public std::numeric_limits<T>
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{
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static inline T min BOOST_PREVENT_MACRO_SUBSTITUTION ()
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{
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return std::numeric_limits<T>::is_signed && (std::numeric_limits<T>::min)() >= 0
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? T(-(std::numeric_limits<T>::max)()) : (std::numeric_limits<T>::min)();
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}
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};
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# if BOOST_MSVC
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# pragma warning(pop)
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#elif defined(__BORLANDC__)
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# pragma option pop
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# endif
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} // namespace detail
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#endif
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template<typename Target, typename Source>
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inline Target numeric_cast(Source arg)
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{
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// typedefs abbreviating respective trait classes
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typedef detail::fixed_numeric_limits<Source> arg_traits;
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typedef detail::fixed_numeric_limits<Target> result_traits;
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#if defined(BOOST_STRICT_CONFIG) \
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|| (!defined(__HP_aCC) || __HP_aCC > 33900) \
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&& (!defined(BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS) \
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|| defined(BOOST_SGI_CPP_LIMITS))
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// typedefs that act as compile time assertions
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// (to be replaced by boost compile time assertions
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// as and when they become available and are stable)
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typedef bool argument_must_be_numeric[arg_traits::is_specialized];
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typedef bool result_must_be_numeric[result_traits::is_specialized];
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const bool arg_is_signed = arg_traits::is_signed;
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const bool result_is_signed = result_traits::is_signed;
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const bool same_sign = arg_is_signed == result_is_signed;
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if (less_than_type_min<arg_is_signed, result_is_signed>::check(arg, (result_traits::min)())
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|| greater_than_type_max<same_sign, arg_is_signed>::check(arg, (result_traits::max)())
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)
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#else // We need to use #pragma hacks if available
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# if BOOST_MSVC
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# pragma warning(push)
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# pragma warning(disable : 4018)
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#elif defined(__BORLANDC__)
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#pragma option push -w-8012
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# endif
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if ((arg < 0 && !result_traits::is_signed) // loss of negative range
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|| (arg_traits::is_signed && arg < (result_traits::min)()) // underflow
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|| arg > (result_traits::max)()) // overflow
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# if BOOST_MSVC
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# pragma warning(pop)
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#elif defined(__BORLANDC__)
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#pragma option pop
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# endif
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#endif
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{
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throw bad_numeric_cast();
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}
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return static_cast<Target>(arg);
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} // numeric_cast
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} // namespace boost
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#endif // BOOST_OLD_NUMERIC_CAST_HPP
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