objectVersion.h

/* Copyright (c) 2009-2016, Stefan Eilemann <eile@equalizergraphics.com>
 *
 * This file is part of Collage <https://github.com/Eyescale/Collage>
 *
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License version 2.1 as published
 * by the Free Software Foundation.
 *
 * This library is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
 * details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#ifndef CO_OBJECTVERSION_H
#define CO_OBJECTVERSION_H

#include <co/api.h>
#include <co/types.h>
#include <lunchbox/bitOperation.h>
#include <lunchbox/stdExt.h>
#include <iostream>

namespace co
{
static const uint128_t VERSION_NONE( 0, 0 );
static const uint128_t VERSION_FIRST( 0, 1 );
static const uint128_t VERSION_NEWEST( 0, 0xfffffffffffffffbull );
static const uint128_t VERSION_OLDEST( 0, 0xfffffffffffffffcull );
static const uint128_t VERSION_NEXT( 0, 0xfffffffffffffffdull );
static const uint128_t VERSION_INVALID( 0, 0xfffffffffffffffeull );
static const uint128_t VERSION_HEAD( 0, 0xffffffffffffffffull );

struct ObjectVersion
{
    CO_API ObjectVersion();

    CO_API ObjectVersion( const uint128_t& identifier,
                          const uint128_t& version );

    CO_API explicit ObjectVersion( const Object* object );

    CO_API explicit ObjectVersion( const Object& object );

    template< class R > explicit ObjectVersion( lunchbox::RefPtr< R > object )
        { *this = object.get(); }

    CO_API ObjectVersion& operator = ( const Object* object );

    bool operator == ( const ObjectVersion& value ) const
    {
        return ( identifier == value.identifier && version == value.version );
    }

    bool operator != ( const ObjectVersion& value ) const
    {
        return ( identifier != value.identifier || version != value.version );
    }

    bool operator < ( const ObjectVersion& rhs ) const 
    {
        return identifier < rhs.identifier ||
               ( identifier == rhs.identifier && version < rhs.version );
    }

    bool operator > ( const ObjectVersion& rhs ) const 
    {
        return identifier > rhs.identifier ||
               ( identifier == rhs.identifier && version > rhs.version );
    }

    explicit operator bool() const
        { return identifier != 0 && version != VERSION_NONE; }

    bool operator ! () const
        { return identifier == 0 || version == VERSION_NONE; }

    uint128_t identifier; 
    uint128_t version; 
};

inline std::ostream& operator << (std::ostream& os, const ObjectVersion& ov)
{ return os << "id " << ov.identifier << " v" << ov.version; }
}

namespace lunchbox
{
template<> inline void byteswap( co::ObjectVersion& value ) 
{
    lunchbox::byteswap( value.identifier );
    lunchbox::byteswap( value.version );
}
}

LB_STDEXT_NAMESPACE_OPEN
#ifdef LB_STDEXT_MSVC

template<>
inline size_t hash_compare< co::ObjectVersion >::operator()
    ( const co::ObjectVersion& key ) const
{
    const size_t hashVersion = hash_value( key.version );
    const size_t hashID = hash_value( key.identifier );

    return hash_value( hashVersion ^ hashID );
}
#else

template<> struct hash< co::ObjectVersion >
{
    template< typename P > size_t operator()( const P& key ) const
        {
            return hash< uint64_t >()( hash_value( key.version ) ^
                                       hash_value( key.identifier ));
        }
};
#endif
LB_STDEXT_NAMESPACE_CLOSE

#endif // CO_OBJECT_H