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1 | // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com) |
2 | // (C) Copyright 2005-2007 Jonathan Turkanis | |
3 | // Distributed under the Boost Software License, Version 1.0. (See accompanying | |
4 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.) | |
5 | ||
6 | // See http://www.boost.org/libs/iostreams for documentation. | |
7 | ||
8 | // Recent changes to Boost.Optional involving assigment broke Boost.Iostreams, | |
9 | // in a way which could be remedied only by relying on the deprecated reset | |
10 | // functions; with VC6, even reset didn't work. Until this problem is | |
11 | // understood, Iostreams will use a private version of optional with a smart | |
12 | // pointer interface. | |
13 | ||
14 | #ifndef BOOST_IOSTREAMS_DETAIL_OPTIONAL_HPP_INCLUDED | |
15 | #define BOOST_IOSTREAMS_DETAIL_OPTIONAL_HPP_INCLUDED | |
16 | ||
17 | #if defined(_MSC_VER) | |
18 | # pragma once | |
19 | #endif | |
20 | ||
21 | #include <boost/assert.hpp> | |
22 | #include <boost/mpl/int.hpp> | |
23 | #include <boost/type_traits/aligned_storage.hpp> | |
24 | #include <boost/type_traits/alignment_of.hpp> | |
25 | ||
26 | namespace boost { namespace iostreams { namespace detail { | |
27 | ||
28 | // Taken from <boost/optional.hpp>. | |
29 | template<class T> | |
30 | class aligned_storage | |
31 | { | |
32 | // Borland ICEs if unnamed unions are used for this! | |
33 | union dummy_u | |
34 | { | |
35 | char data[ sizeof(T) ]; | |
36 | BOOST_DEDUCED_TYPENAME type_with_alignment< | |
37 | ::boost::alignment_of<T>::value >::type aligner_; | |
38 | } dummy_ ; | |
39 | ||
40 | public: | |
41 | ||
42 | void const* address() const { return &dummy_.data[0]; } | |
43 | void * address() { return &dummy_.data[0]; } | |
44 | }; | |
45 | ||
46 | template<typename T> | |
47 | class optional { | |
48 | public: | |
49 | typedef T element_type; | |
50 | optional() : initialized_(false) { } | |
51 | optional(const T& t) : initialized_(false) { reset(t); } | |
52 | ~optional() { reset(); } | |
53 | T& operator*() | |
54 | { | |
55 | BOOST_ASSERT(initialized_); | |
56 | return *static_cast<T*>(address()); | |
57 | } | |
58 | const T& operator*() const | |
59 | { | |
60 | BOOST_ASSERT(initialized_); | |
61 | return *static_cast<const T*>(address()); | |
62 | } | |
63 | T* operator->() | |
64 | { | |
65 | BOOST_ASSERT(initialized_); | |
66 | return static_cast<T*>(address()); | |
67 | } | |
68 | const T* operator->() const | |
69 | { | |
70 | BOOST_ASSERT(initialized_); | |
71 | return static_cast<const T*>(address()); | |
72 | } | |
73 | T* get() | |
74 | { | |
75 | BOOST_ASSERT(initialized_); | |
76 | return static_cast<T*>(address()); | |
77 | } | |
78 | const T* get() const | |
79 | { | |
80 | BOOST_ASSERT(initialized_); | |
81 | return static_cast<const T*>(address()); | |
82 | } | |
83 | void reset() | |
84 | { | |
85 | if (initialized_) { | |
86 | #if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564)) || \ | |
87 | BOOST_WORKAROUND(__IBMCPP__, BOOST_TESTED_AT(600)) \ | |
88 | /**/ | |
89 | T* t = static_cast<T*>(address()); | |
90 | t->~T(); | |
91 | #else | |
92 | static_cast<T*>(address())->T::~T(); | |
93 | #endif | |
94 | initialized_ = false; | |
95 | } | |
96 | } | |
97 | void reset(const T& t) | |
98 | { | |
99 | reset(); | |
100 | new (address()) T(t); | |
101 | initialized_ = true; | |
102 | } | |
103 | private: | |
104 | optional(const optional&); | |
105 | optional& operator=(const optional&); | |
106 | void* address() { return &storage_; } | |
107 | const void* address() const { return &storage_; } | |
108 | aligned_storage<T> storage_; | |
109 | bool initialized_; | |
110 | }; | |
111 | ||
112 | } } } // End namespaces detail, iostreams, boost. | |
113 | ||
114 | #endif // #ifndef BOOST_IOSTREAMS_DETAIL_OPTIONAL_HPP_INCLUDED |