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Jeff Thompson86b6d642013-10-17 15:01:56 -07001// (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 NDNBOOST_IOSTREAMS_DETAIL_OPTIONAL_HPP_INCLUDED
15#define NDNBOOST_IOSTREAMS_DETAIL_OPTIONAL_HPP_INCLUDED
16
17#if defined(_MSC_VER) && (_MSC_VER >= 1020)
18# pragma once
19#endif
20
21#include <ndnboost/assert.hpp>
22#include <ndnboost/mpl/int.hpp>
23#include <ndnboost/type_traits/aligned_storage.hpp>
24#include <ndnboost/type_traits/alignment_of.hpp>
25
26namespace ndnboost { namespace iostreams { namespace detail {
27
28// Taken from <ndnboost/optional.hpp>.
29template<class T>
30class aligned_storage
31{
32 // Borland ICEs if unnamed unions are used for this!
33 union dummy_u
34 {
35 char data[ sizeof(T) ];
36 NDNBOOST_DEDUCED_TYPENAME type_with_alignment<
37 ::ndnboost::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
46template<typename T>
47class optional {
48public:
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 NDNBOOST_ASSERT(initialized_);
56 return *static_cast<T*>(address());
57 }
58 const T& operator*() const
59 {
60 NDNBOOST_ASSERT(initialized_);
61 return *static_cast<const T*>(address());
62 }
63 T* operator->()
64 {
65 NDNBOOST_ASSERT(initialized_);
66 return static_cast<T*>(address());
67 }
68 const T* operator->() const
69 {
70 NDNBOOST_ASSERT(initialized_);
71 return static_cast<const T*>(address());
72 }
73 T* get()
74 {
75 NDNBOOST_ASSERT(initialized_);
76 return static_cast<T*>(address());
77 }
78 const T* get() const
79 {
80 NDNBOOST_ASSERT(initialized_);
81 return static_cast<const T*>(address());
82 }
83 void reset()
84 {
85 if (initialized_) {
86 #if NDNBOOST_WORKAROUND(__BORLANDC__, NDNBOOST_TESTED_AT(0x564)) || \
87 NDNBOOST_WORKAROUND(__IBMCPP__, NDNBOOST_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 }
103private:
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 NDNBOOST_IOSTREAMS_DETAIL_OPTIONAL_HPP_INCLUDED