1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
|
// boost polymorphic_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
// 09 Jun 14 "cast.hpp" was renamed to "polymorphic_cast.hpp" and
// inclusion of numeric_cast was removed (Antony Polukhin)
// 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_POLYMORPHIC_CAST_HPP
#define BOOST_POLYMORPHIC_CAST_HPP
# include <boost/config.hpp>
# include <boost/assert.hpp>
# include <typeinfo>
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)
{
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_ASSERT( dynamic_cast<Target>(x) == x ); // detect logic error
return static_cast<Target>(x);
}
} // namespace boost
#endif // BOOST_POLYMORPHIC_CAST_HPP
|
Swift