// (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)
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// (C) Copyright 2005-2007 Jonathan Turkanis
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file 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/iostreams for documentation.
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// Recent changes to Boost.Optional involving assigment broke Boost.Iostreams,
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// in a way which could be remedied only by relying on the deprecated reset
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// functions; with VC6, even reset didn't work. Until this problem is
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// understood, Iostreams will use a private version of optional with a smart
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// pointer interface.
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#ifndef BOOST_IOSTREAMS_DETAIL_OPTIONAL_HPP_INCLUDED
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#define BOOST_IOSTREAMS_DETAIL_OPTIONAL_HPP_INCLUDED
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#if defined(_MSC_VER)
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# pragma once
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#endif
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#include <boost/assert.hpp>
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#include <boost/mpl/int.hpp>
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#include <boost/type_traits/aligned_storage.hpp>
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#include <boost/type_traits/alignment_of.hpp>
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namespace boost { namespace iostreams { namespace detail {
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// Taken from <boost/optional.hpp>.
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template<class T>
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class aligned_storage
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{
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// Borland ICEs if unnamed unions are used for this!
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union dummy_u
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{
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char data[ sizeof(T) ];
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BOOST_DEDUCED_TYPENAME type_with_alignment<
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::boost::alignment_of<T>::value >::type aligner_;
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} dummy_ ;
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public:
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void const* address() const { return &dummy_.data[0]; }
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void * address() { return &dummy_.data[0]; }
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};
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template<typename T>
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class optional {
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public:
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typedef T element_type;
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optional() : initialized_(false) { }
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optional(const T& t) : initialized_(false) { reset(t); }
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~optional() { reset(); }
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T& operator*()
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{
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BOOST_ASSERT(initialized_);
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return *static_cast<T*>(address());
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}
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const T& operator*() const
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{
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BOOST_ASSERT(initialized_);
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return *static_cast<const T*>(address());
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}
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T* operator->()
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{
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BOOST_ASSERT(initialized_);
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return static_cast<T*>(address());
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}
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const T* operator->() const
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{
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BOOST_ASSERT(initialized_);
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return static_cast<const T*>(address());
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}
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T* get()
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{
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BOOST_ASSERT(initialized_);
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return static_cast<T*>(address());
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}
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const T* get() const
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{
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BOOST_ASSERT(initialized_);
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return static_cast<const T*>(address());
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}
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void reset()
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{
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if (initialized_) {
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#if BOOST_WORKAROUND(BOOST_BORLANDC, BOOST_TESTED_AT(0x564)) || \
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BOOST_WORKAROUND(__IBMCPP__, BOOST_TESTED_AT(600)) \
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/**/
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T* t = static_cast<T*>(address());
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t->~T();
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#else
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static_cast<T*>(address())->T::~T();
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#endif
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initialized_ = false;
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}
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}
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void reset(const T& t)
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{
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reset();
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new (address()) T(t);
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initialized_ = true;
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}
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private:
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optional(const optional&);
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optional& operator=(const optional&);
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void* address() { return &storage_; }
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const void* address() const { return &storage_; }
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aligned_storage<T> storage_;
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bool initialized_;
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};
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} } } // End namespaces detail, iostreams, boost.
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#endif // #ifndef BOOST_IOSTREAMS_DETAIL_OPTIONAL_HPP_INCLUDED
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