diff --git a/include/boost/optional.hpp b/include/boost/optional.hpp index dd6ffc1..1a82a64 100644 --- a/include/boost/optional.hpp +++ b/include/boost/optional.hpp @@ -1,189 +1,316 @@ -//----------------------------------------------------------------------------- -// boost optional.hpp header file -// See http://www.boost.org for updates, documentation, and revision history. -//----------------------------------------------------------------------------- +// (C) 2003, Fernando Luis Cacciola Carballal. // -// Copyright (c) 2002 -// Eric Friedman +// This material is provided "as is", with absolutely no warranty expressed +// or implied. Any use is at your own risk. // -// Permission to use, copy, modify, distribute and sell this software -// and its documentation for any purpose is hereby granted without fee, -// provided that the above copyright notice appears in all copies and -// that both the copyright notice and this permission notice appear in -// supporting documentation. No representations are made about the -// suitability of this software for any purpose. It is provided "as is" -// without express or implied warranty. +// Permission to use or copy this software for any purpose is hereby granted +// without fee, provided the above notices are retained on all copies. +// Permission to modify the code and to distribute modified code is granted, +// provided the above notices are retained, and a notice that the code was +// modified is included with the above copyright notice. +// +// See http://www.boost.org/lib/optional for documentation. +// +// You are welcome to contact the author at: +// fernando_cacciola@hotmail.com +// +#ifndef BOOST_OPTIONAL_FLC_19NOV2002_HPP +#define BOOST_OPTIONAL_FLC_19NOV2002_HPP -#ifndef BOOST_OPTIONAL_HPP -#define BOOST_OPTIONAL_HPP +#include +#include -#include // for placement-new +#include "boost/config.hpp" +#include "boost/assert.hpp" +#include "boost/type_traits/alignment_of.hpp" +#include "boost/type_traits/type_with_alignment.hpp" -#include "boost/aligned_storage.hpp" -#include "boost/move.hpp" +#if BOOST_WORKAROUND(BOOST_MSVC, == 1200) +// VC6.0 has the following bug: +// When a templated assignment operator exist, an implicit conversion +// constructing an optional is used when assigment of the form: +// optional opt ; opt = T(...); +// is compiled. +// However, optional's ctor is _explicit_ and the assignemt shouldn't compile. +// Therefore, for VC6.0 templated assignment is disabled. +// +#define BOOST_OPTIONAL_NO_CONVERTING_ASSIGNMENT +#endif -namespace boost { +#if BOOST_WORKAROUND(BOOST_MSVC, == 1300) +// VC7.0 has the following bug: +// When both a non-template and a template copy-ctor exist +// and the templated version is made 'explicit', the explicit is also +// given to the non-templated version, making the class non-implicitely-copyable. +// +#define BOOST_OPTIONAL_NO_CONVERTING_COPY_CTOR +#endif -template -class optional - : public moveable< optional > +namespace boost { - typedef aligned_storage< - sizeof(T) - , alignment_of::value - > storage_t; - - bool empty_; - storage_t storage_; - -public: // structors - ~optional() + namespace optional_detail + { + template + class aligned_storage { - clear(); + // Borland ICEs if unnamed unions are used for this! + union dummy_u + { + char data[ sizeof(T) ]; + type_with_alignment< ::boost::alignment_of::value > aligner_; + } dummy_ ; + + public: + + void const* address() const { return &dummy_.data[0]; } + void * address() { return &dummy_.data[0]; } + } ; + } + +template +class optional +{ + typedef optional this_type ; + + typedef optional_detail::aligned_storage storage_type ; + + typedef void (this_type::*unspecified_bool_type)(); + + public : + + typedef T value_type ; + + // Creates an optional uninitialized. + // No-throw + optional () + : + m_initialized(false) {} + + // Creates an optional initialized with 'val'. + // Can throw if T::T(T const&) does + explicit optional ( T const& val ) + : + m_initialized(false) + { + construct(val); } - optional() - : empty_(true) +#ifndef BOOST_OPTIONAL_NO_CONVERTING_COPY_CTOR + // NOTE: MSVC needs templated versions first + + // Creates a deep copy of another convertible optional + // Requires a valid conversion from U to T. + // Can throw if T::T(U const&) does + template + explicit optional ( optional const& rhs ) + : + m_initialized(false) { + if ( rhs ) + construct(*rhs); + } +#endif + + // Creates a deep copy of another optional + // Can throw if T::T(T const&) does + optional ( optional const& rhs ) + : + m_initialized(false) + { + if ( rhs ) + construct(*rhs); } - optional(const optional& operand) - : empty_(operand.empty_) - { - if (!empty_) - new(storage_.address()) T(operand.get()); - } + // No-throw (assuming T::~T() doesn't) + ~optional() { destroy() ; } - optional(move_source source) - : empty_(source.get().empty_) - { - if (!empty_) +#ifndef BOOST_OPTIONAL_NO_CONVERTING_ASSIGNMENT + // Assigns from another convertible optional (converts && deep-copies the rhs value) + // Requires a valid conversion from U to T. + // Basic Guarantee: If T::T( U const& ) throws, this is left UNINITIALIZED + template + optional& operator= ( optional const& rhs ) + { + destroy(); // no-throw + + if ( rhs ) { - optional& operand = source.get(); - new(storage.address()) T( move(operand.get()) ); + // An exception can be thrown here. + // It it happens, THIS will be left uninitialized. + construct(*rhs); } - } + return *this ; + } +#endif - optional(const T& operand) - : empty_(false) - { - new(storage_.address()) T(operand); - } + // Assigns from another optional (deep-copies the rhs value) + // Basic Guarantee: If T::T( T const& ) throws, this is left UNINITIALIZED + optional& operator= ( optional const& rhs ) + { + destroy(); // no-throw - optional(move_source source) - : empty_(false) - { - T& operand = source.get(); - new(storage_.address()) T( move(operand) ); - } - -public: // modifiers - optional& operator=(const optional& rhs) - { - // If rhs is empty... - if (rhs.empty_) + if ( rhs ) { - // ...then simply clear *this and leave: - clear(); - return *this; + // An exception can be thrown here. + // It it happens, THIS will be left uninitialized. + construct(*rhs); } + return *this ; + } - // Otherwise, assign rhs's content to *this: - return (*this = rhs.get()); - } + // Destroys the current value, if any, leaving this UNINITIALIZED + // No-throw (assuming T::~T() doesn't) + void reset() + { + destroy(); + } - optional& operator=(move_source source) - { - // If rhs is empty... - if (rhs.empty_) - { - // ...then simply clear *this and leave: - clear(); - return *this; - } + // Replaces the current value -if any- with 'val' + // Basic Guarantee: If T::T( T const& ) throws this is left UNINITIALIZED. + void reset ( T const& val ) + { + destroy(); + construct(val); + } - optional& rhs = source.get(); + // Returns a pointer to the value if this is initialized, otherwise, + // returns NULL. + // No-throw + T const* get() const { return m_initialized ? static_cast(m_storage.address()) : 0 ; } + T* get() { return m_initialized ? static_cast (m_storage.address()) : 0 ; } - // Otherwise, move rhs's content to *this: - return (*this = move(rhs.get())); - } + // Returns a pointer to the value if this is initialized, otherwise, + // the behaviour is UNDEFINED + // No-throw + T const* operator->() const { BOOST_ASSERT(m_initialized) ; return get() ; } + T* operator->() { BOOST_ASSERT(m_initialized) ; return get() ; } - optional& operator=(const T& rhs) - { - // If *this is empty... - if (empty_) - { - // ...then copy rhs to *this's storage: - new(storage_.address()) T(rhs); - empty_ = false; - } - else - { - // ...otherwise, assign rhs to *this's content: - get() = rhs; - } + // Returns a reference to the value if this is initialized, otherwise, + // the behaviour is UNDEFINED + // No-throw + T const& operator *() const { BOOST_ASSERT(m_initialized) ; return *get() ; } + T& operator *() { BOOST_ASSERT(m_initialized) ; return *get() ; } - return *this; - } + // implicit conversion to "bool" + // No-throw + operator unspecified_bool_type() const { return m_initialized ? &this_type::destroy : 0 ; } - optional& operator=(move_source source) - { - T& rhs = source.get(); + // This is provided for those compilers which don't like the conversion to bool + // on some contexts. + bool operator!() const { return !m_initialized ; } - // If *this is empty... - if (empty_) - { - // ...then move-construct rhs to *this's storage: - new(storage_.address()) T( move(rhs) ); - empty_ = false; - } - else - { - // ...otherwise, move-assign rhs to *this's content: - get() = move(rhs); - } + private : - return *this; - } + void construct ( T const& val ) + { + new (m_storage.address()) T(val) ; + m_initialized = true ; + } - void swap(optional& operand) - { - // Move *this into temporary storage... - optional temp( move(get()) ); + void destroy() + { + if ( m_initialized ) + { + get()->~T() ; + m_initialized = false ; + } + } - // ...move operand into *this... - *this = move(operand); + bool m_initialized ; + storage_type m_storage ; +} ; - // ...and move temporary into operand: - operand = move(temp); - } +// Returns a pointer to the value if this is initialized, otherwise, returns NULL. +// No-throw +template +inline +T const* get_pointer ( optional const& opt ) +{ + return opt.get() ; +} - void clear() - { - if (!empty_) - { - get().~T(); - empty_ = true; - } - } +template +inline +T* get_pointer ( optional& opt ) +{ + return opt.get() ; +} -public: // queries - bool empty() const - { - return empty_; - } +// template bool equal_pointees(OP const& x, OP const& y); +// +// Being OP a model of OptionalPointee (either a pointer or an optional): +// +// If both x and y have valid pointees, returns the result of (*x == *y) +// If only one has a valid pointee, returns false. +// If none have valid pointees, returns true. +// No-throw +template +inline +bool equal_pointees ( OptionalPointee const& x, OptionalPointee const& y ) +{ + return (!x) != (!y) ? false : ( !x ? true : (*x) == (*y) ) ; +} - T& get() - { - return *static_cast(storage_.address()); - } +// optional's operator == and != have deep-semantics (compare values). +// WARNING: This is UNLIKE pointers. Use equal_pointees() in generic code instead. +template +inline +bool operator == ( optional const& x, optional const& y ) +{ return equal_pointees(x,y); } + +template +inline +bool operator != ( optional const& x, optional const& y ) +{ return !( x == y ) ; } + + +// +// The following swap implementation follows the GCC workaround as found in +// "boost/detail/compressed_pair.hpp" +// +namespace optional_detail { + +#ifdef __GNUC__ + // workaround for GCC (JM): + using std::swap; +#endif + +// optional's swap: +// If both are initialized, calls swap(T&, T&), with whatever exception guarantess are given there. +// If only one is initialized, calls I.reset() and U.reset(*I), with the Basic Guarantee +// If both are uninitialized, do nothing (no-throw) +template +inline +void optional_swap ( optional& x, optional& y ) +{ + if ( !x && !!y ) + { + x.reset(*y); // Basic guarantee. + y.reset(); + } + else if ( !!x && !y ) + { + y.reset(*x); // Basic guarantee. + x.reset(); + } + else if ( !!x && !!y ) + { +#ifndef __GNUC__ + using std::swap ; +#endif + swap(*x,*y); + } +} + +} // namespace optional_detail + +template inline void swap ( optional& x, optional& y ) +{ + optional_detail::optional_swap(x,y); +} - const T& get() const - { - return *static_cast(storage_.address()); - } -}; } // namespace boost -#endif // BOOST_OPTIONAL_HPP +#endif +