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 /*****************************************************************************/
 /**

  * \file portable_iarchive.hpp

  * \brief Provides an archive to read from portable binary files.

  * \author christian.pfligersdorffer@gmx.at

  * \version 5.1

  *

  * This pair of archives brings the advantages of binary streams to the cross

  * platform boost::serialization user. While being almost as fast as the native

  * binary archive it allows its files to be exchanged between cpu architectures

  * using different byte order (endianness). Speaking of speed: in serializing

  * numbers the (portable) binary approach is approximately ten times faster than

  * the ascii implementation (that is inherently portable)!

  *

  * Based on the portable archive example by Robert Ramey this implementation

  * uses Beman Dawes endian library and fp_utilities from Johan Rade, both being

  * in boost since 1.36. Prior to that you need to add them both (header only)

  * to your boost directory before you're able to use the archives provided. 

  * Our archives have been tested successfully for boost versions 1.33 to 1.49!

  *

  * \note Correct behaviour has so far been confirmed using PowerPC-32, x86-32

  *       and x86-64 platforms featuring different byte order. So there is a good

  *       chance it will instantly work for your specific setup. If you encounter

  *       problems or have suggestions please contact the author.

  *

  * \note Version 5.1 is now compatible with boost up to version 1.59. Thanks to

  *       ecotax for pointing to the issue with shared_ptr_helper.

  *

  * \note Version 5.0 is now compatible with boost up to version 1.49 and enables

  *       serialization of std::wstring by converting it to/from utf8 (thanks to

  *       Arash Abghari for this suggestion). With that all unit tests from the

  *       serialization library pass again with the notable exception of user

  *       defined primitive types. Those are not supported and as a result any

  *       user defined type to be used with the portable archives are required 

  *       to be at least object_serializable.

  *

  * \note Version 4.2 maintains compatibility with the latest boost 1.45 and adds

  *       serialization of special floating point values inf and NaN as proposed

  *       by Francois Mauger.

  *

  * \note Version 4.1 makes the archives work together with boost 1.40 and 1.41.

  *       Thanks to Francois Mauger for his suggestions.

  *

  * \note Version 4 removes one level of the inheritance hierarchy and directly

  *       builds upon binary primitive and basic binary archive, thereby fixing

  *       the last open issue regarding array serialization. Thanks to Robert

  *       Ramey for the hint.

  *

  * \note A few fixes introduced in version 3.1 let the archives pass all of the

  *       serialization tests. Thanks to Sergey Morozov for running the tests.

  *       Wouter Bijlsma pointed out where to find the fp_utilities and endian

  *       libraries headers inside the boost distribution. I would never have

  *       found them so thank him it works out of the box since boost 1.36.

  *

  * \note With Version 3.0 the archives have been made portable across different

  *       boost versions. For that purpose a header is added to the data that

  *       supplies the underlying serialization library version. Backwards

  *       compatibility is maintained by assuming library version boost 1.33 if

  *       the iarchive is created using the no_header flag. Whether a header is

  *       present or not can be guessed by peeking into the stream: the header's

  *       first byte is the magic number 127 coinciding with 'e'|'o'|'s' :-)

  *

  * \note Version 2.1 removes several compiler warnings and enhances floating

  *       point diagnostics to inform the user if some preconditions are violated

  *       on his platform. We do not strive for the universally portable solution

  *       in binary floating point serialization as desired by some boost users.

  *       Instead we support only the most widely used IEEE 754 format and try to

  *       detect when requirements are not met and hence our approach must fail.

  *       Contributions we made by Johan Rade and Ákos Maróy.

  *

  * \note Version 2.0 fixes a serious bug that effectively transformed most

  *       of negative integral values into positive values! For example the two

  *       numbers -12 and 234 were stored in the same 8-bit pattern and later

  *       always restored to 234. This was fixed in this version in a way that

  *       does not change the interpretation of existing archives that did work

  *       because there were no negative numbers. The other way round archives

  *       created by version 2.0 and containing negative numbers will raise an

  *       integer type size exception when reading it with version 1.0. Thanks

  *       to Markus Frohnmaier for testing the archives and finding the bug.

  *

  * \copyright The boost software license applies.

  */
 /*****************************************************************************/
 
 #ifndef CondFormats_Serialization_portable_iarchive_hpp
 #define CondFormats_Serialization_portable_iarchive_hpp
 
 #include <istream>
 
 // basic headers

 #include <boost/version.hpp>
 #include <boost/utility/enable_if.hpp>
 #include <boost/archive/basic_binary_iprimitive.hpp>
 #include <boost/archive/basic_binary_iarchive.hpp>
 
 #if BOOST_VERSION >= 103500 && BOOST_VERSION < 105600
 #include <boost/archive/shared_ptr_helper.hpp>
 #endif
 
 // funny polymorphics

 #if BOOST_VERSION < 103500
 #include <boost/archive/detail/polymorphic_iarchive_impl.hpp>
 #define POLYMORPHIC(T) boost::archive::detail::polymorphic_iarchive_impl<T>
 
 #elif BOOST_VERSION < 103600
 #include <boost/archive/detail/polymorphic_iarchive_dispatch.hpp>
 #define POLYMORPHIC(T) boost::archive::detail::polymorphic_iarchive_dispatch<T>
 
 #else
 #include <boost/archive/detail/polymorphic_iarchive_route.hpp>
 #define POLYMORPHIC(T) boost::archive::detail::polymorphic_iarchive_route<T>
 #endif
 
 // endian and fpclassify

 #include <boost/math/special_functions/fpclassify.hpp>
 #include <boost/endian/conversion.hpp>
 
 // namespace alias

 #if BOOST_VERSION < 103800
 namespace fp = boost::math;
 #elif BOOST_VERSION >= 106900
 namespace fp = boost::math;
 #else
 namespace fp = boost::spirit::math;
 #endif
 
 #if BOOST_VERSION >= 104500 && !defined BOOST_NO_STD_WSTRING
 // used for wstring to utf8 conversion

 #include <boost/program_options/config.hpp>
 #include <boost/program_options/detail/convert.hpp>
 #endif
 
 // generic type traits for numeric types

 #include <boost/type_traits/is_integral.hpp>
 #include <boost/type_traits/is_unsigned.hpp>
 #include <boost/type_traits/is_arithmetic.hpp>
 #include <boost/type_traits/is_floating_point.hpp>
 
 #include "portable_archive_exception.hpp"
 
 // hint from Johan Rade: on VMS there is still support for

 // the VAX floating point format and this macro detects it

 #if defined(__vms) && defined(__DECCXX) && !__IEEE_FLOAT
 #error "VAX floating point format is not supported!"
 #endif
 
 namespace eos {
 
   // forward declaration

   class portable_iarchive;
 
   typedef boost::archive::basic_binary_iprimitive<portable_iarchive
 #if BOOST_VERSION < 103400
                                                   ,
                                                   std::istream
 #else
                                                   ,
                                                   std::istream::char_type,
                                                   std::istream::traits_type
 #endif
                                                   >
       portable_iprimitive;
 
   /**

      * \brief Portable binary input archive using little endian format.

      *

      * This archive addresses integer size, endianness and floating point types so

      * that data can be transferred across different systems. There may still be

      * constraints as to what systems are compatible and the user will have to take

      * care that e.g. a very large int being saved on a 64 bit machine will result

      * in a portable_archive_exception if loaded into an int on a 32 bit system.

      * A possible workaround to this would be to use fixed types like

      * boost::uint64_t in your serialization structures.

      *

      * \note The class is based on the portable binary example by Robert Ramey and

      *       uses Beman Dawes endian library plus fp_utilities by Johan Rade.

      */
   class portable_iarchive : public portable_iprimitive
 
       // the example derives from common_oarchive but that lacks the

       // load_override functions so we chose to stay one level higher

       ,
                             public boost::archive::basic_binary_iarchive<portable_iarchive>
 #if BOOST_VERSION >= 103500 && BOOST_VERSION < 105600
       // mix-in helper class for serializing shared_ptr

       ,
                             public boost::archive::detail::shared_ptr_helper
 #endif
   {
     // only needed for Robert's hack in basic_binary_iarchive::init

     friend class boost::archive::basic_binary_iarchive<portable_iarchive>;
 
     // workaround for gcc: use a dummy struct

     // as additional argument type for overloading

     template <int>
     struct dummy {
       dummy(int) {}
     };
 
     // loads directly from stream

     inline signed char load_signed_char() {
       signed char c;
       portable_iprimitive::load(c);
       return c;
     }
 
     // archive initialization

     void init(unsigned flags) {
       using namespace boost::archive;
       archive_version_type input_library_version(3);
 
       // it is vital to have version information!

       // if we don't have any we assume boost 1.33

       if (flags & no_header)
         set_library_version(input_library_version);
 
       // extract and check the magic eos byte

       else if (load_signed_char() != magic_byte)
         throw archive_exception(archive_exception::invalid_signature);
 
       else {
         // extract version information

         operator>>(input_library_version);
 
         // throw if file version is newer than we are

         if (input_library_version > archive_version)
           throw archive_exception(archive_exception::unsupported_version);
 
         // else set the library version accordingly

         else
           set_library_version(input_library_version);
       }
     }
 
   public:
     /**

          * \brief Constructor on a stream using ios::binary mode!

          *

          * We cannot call basic_binary_iprimitive::init which tries to detect

          * if the binary archive stems from a different platform by examining

          * type sizes.

          *

          * We could have called basic_binary_iarchive::init which would create

          * the boost::serialization standard archive header containing also the

          * library version. Due to efficiency we stick with our own.

          */
     portable_iarchive(std::istream& is, unsigned flags = 0)
 #if BOOST_VERSION < 103400
         : portable_iprimitive(is, flags & boost::archive::no_codecvt)
 #else
         : portable_iprimitive(*is.rdbuf(), flags & boost::archive::no_codecvt)
 #endif
           ,
           boost::archive::basic_binary_iarchive<portable_iarchive>(flags) {
       init(flags);
     }
 
 #if BOOST_VERSION >= 103400
     portable_iarchive(std::streambuf& sb, unsigned flags = 0)
         : portable_iprimitive(sb, flags & boost::archive::no_codecvt),
           boost::archive::basic_binary_iarchive<portable_iarchive>(flags) {
       init(flags);
     }
 #endif
 
     //! Load narrow strings.

     void load(std::string& s) { portable_iprimitive::load(s); }
 
 #ifndef BOOST_NO_STD_WSTRING
     /**

          * \brief Load wide strings.

          *

          * This is rather tricky to get right for true portability as there

          * are so many different character encodings around. However, wide

          * strings that are encoded in one of the Unicode schemes only need

          * to be _transcoded_ which is a lot easier actually.

          *

          * We generate the output string to be encoded in the system's native

          * format, ie. UTF-16 on Windows and UTF-32 on Linux machines. Don't

          * know about Mac here so I can't really say about that.

          */
     void load(std::wstring& s) {
       std::string utf8;
       load(utf8);
       s = boost::from_utf8(utf8);
     }
 #endif
 
     /**

          * \brief Loading bool type.

          *

          * Byte pattern is same as with integer types, so this function

          * is somewhat redundant but treating bool as integer generates

          * a lot of compiler warnings.

          *

          * \note If you cannot compile your application and it says something

          * about load(bool) cannot convert your type A& into bool& then you

          * should check your BOOST_CLASS_IMPLEMENTATION setting for A, as

          * portable_archive is not able to handle custom primitive types in

          * a general manner.

          */
     void load(bool& b) {
       switch (signed char c = load_signed_char()) {
         case 0:
           b = false;
           break;
         case 1:
           b = load_signed_char();
           break;
         default:
           throw portable_archive_exception(c);
       }
     }
 
     /**

          * \brief Load integer types.

          *

          * First we load the size information ie. the number of bytes that 

          * hold the actual data. Then we retrieve the data and transform it

          * to the original value by using load_little_endian.

          */
     template <typename T>
     typename boost::enable_if<boost::is_integral<T> >::type load(T& t, dummy<2> = 0) {
       // get the number of bytes in the stream

       if (signed char size = load_signed_char()) {
         // check for negative value in unsigned type

         if (size < 0 && boost::is_unsigned<T>::value)
           throw portable_archive_exception();
 
         // check that our type T is large enough

         else if ((unsigned)abs(size) > sizeof(T))
           throw portable_archive_exception(size);
 
         // reconstruct the value

         T temp = size < 0 ? -1 : 0;
         load_binary(&temp, abs(size));
 
         // load the value from little endian - it is then converted

         // to the target type T and fits it because size <= sizeof(T)

         t = boost::endian::little_to_native(temp);
       }
 
       else
         t = 0;  // zero optimization

     }
 
     /** 

          * \brief Load floating point types.

          * 

          * We simply rely on fp_traits_non_native to set the bit pattern from the (unsigned)

          * integral type that was stored in the stream. Francois Mauger provided

          * standardized behaviour for special values like inf and NaN, that need to

          * be serialized in his application.

          *

          * \note by Johan Rade (author of the floating point utilities library):

          * Be warned that the math::detail::fp_traits_non_native<T,U>::get_bits() function

          * is *not* guaranteed to give you all bits of the floating point number. It

          * will give you all bits if and only if there is an integer type that has

          * the same size as the floating point you are copying from. It will not

          * give you all bits for double if there is no uint64_t. It will not give

          * you all bits for long double if sizeof(long double) > 8 or there is no

          * uint64_t. 

          * 

          * The member fp_traits<T>::type::coverage will tell you whether all bits

          * are copied. This is a typedef for either math::detail::all_bits or

          * math::detail::not_all_bits. 

          * 

          * If the function does not copy all bits, then it will copy the most

          * significant bits. So if you serialize and deserialize the way you

          * describe, and fp_traits<T>::type::coverage is math::detail::not_all_bits,

          * then your floating point numbers will be truncated. This will introduce

          * small rounding off errors. 

          */
     template <typename T>
     typename boost::enable_if<boost::is_floating_point<T> >::type load(T& t, dummy<3> = 0) {
       typedef typename fp::detail::size_to_precision<sizeof(T), ::std::is_floating_point<T>::value>::type precision;
       typedef typename fp::detail::fp_traits_non_native<T, precision> traits;
 
       // if you end here there are three possibilities:

       // 1. you're serializing a long double which is not portable

       // 2. you're serializing a double but have no 64 bit integer

       // 3. your machine is using an unknown floating point format

       // after reading the note above you still might decide to

       // deactivate this static assert and try if it works out.

       typename traits::bits bits;
       static_assert(sizeof(bits) == sizeof(T));
       static_assert(std::numeric_limits<T>::is_iec559);
 
       load(bits);
       traits::set_bits(t, bits);
 
       // if the no_infnan flag is set we must throw here

       if (get_flags() & no_infnan && !fp::isfinite(t))
         throw portable_archive_exception(t);
 
       // if you end here your floating point type does not support

       // denormalized numbers. this might be the case even though

       // your type conforms to IEC 559 (and thus to IEEE 754)

       if (std::numeric_limits<T>::has_denorm == std::denorm_absent && fp::fpclassify(t) == (int)FP_SUBNORMAL)  // GCC4

         throw portable_archive_exception(t);
     }
 
     // in boost 1.44 version_type was splitted into library_version_type and

     // item_version_type, plus a whole bunch of additional strong typedefs.

     template <typename T>
     typename boost::disable_if<boost::is_arithmetic<T> >::type load(T& t, dummy<4> = 0) {
       // we provide a generic load routine for all types that feature

       // conversion operators into an unsigned integer value like those

       // created through BOOST_STRONG_TYPEDEF(X, some unsigned int) like

       // library_version_type, collection_size_type, item_version_type,

       // class_id_type, object_id_type, version_type and tracking_type

       load((typename boost::uint_t<sizeof(T) * CHAR_BIT>::least&)(t));
     }
   };
 
   // polymorphic portable binary iarchive typedef

   typedef POLYMORPHIC(portable_iarchive) polymorphic_portable_iarchive;
 #undef POLYMORPHIC
 
 }  // namespace eos

 
 // this is required by export which registers all of your

 // classes with all the inbuilt archives plus our archive.

 #if BOOST_VERSION < 103500
 #define BOOST_ARCHIVE_CUSTOM_IARCHIVE_TYPES eos::portable_iarchive
 #else
 BOOST_SERIALIZATION_REGISTER_ARCHIVE(eos::portable_iarchive)
 BOOST_SERIALIZATION_REGISTER_ARCHIVE(eos::polymorphic_portable_iarchive)
 #endif
 
 // if you include this header multiple times and your compiler is picky

 // about multiple template instantiations (eg. gcc is) then you need to

 // define NO_EXPLICIT_TEMPLATE_INSTANTIATION before every include but one

 // or you move the instantiation section into an implementation file

 // #ifndef NO_EXPLICIT_TEMPLATE_INSTANTIATION

 //

 // #include <boost/archive/impl/basic_binary_iarchive.ipp>

 // #include <boost/archive/impl/basic_binary_iprimitive.ipp>

 //

 // #if BOOST_VERSION < 104000

 // #include <boost/archive/impl/archive_pointer_iserializer.ipp>

 // #elif !defined BOOST_ARCHIVE_SERIALIZER_INCLUDED

 // #include <boost/archive/impl/archive_serializer_map.ipp>

 // #define BOOST_ARCHIVE_SERIALIZER_INCLUDED

 // #endif

 //

 // namespace boost {

 //   namespace archive {

 //

 //     // explicitly instantiate for this type of binary stream

 //     template class basic_binary_iarchive<eos::portable_iarchive>;

 //

 //     template class basic_binary_iprimitive<eos::portable_iarchive

 // #if BOOST_VERSION < 103400

 //                                            ,

 //                                            std::istream

 // #else

 //                                            ,

 //                                            std::istream::char_type,

 //                                            std::istream::traits_type

 // #endif

 //                                            >;

 //

 // #if BOOST_VERSION < 104000

 //     template class detail::archive_pointer_iserializer<eos::portable_iarchive>;

 // #else

 //     template class detail::archive_serializer_map<eos::portable_iarchive>;

 //     //template class detail::archive_serializer_map<eos::polymorphic_portable_iarchive>;

 // #endif

 //

 //   }  // namespace archive

 // }  // namespace boost

 //

 // #endif

 
 #endif

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