read.hpp

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//
// (c) Copyright 2013 DESY, Eugen Wintersberger <eugen.wintersberger@desy.de>
//
// This file is part of libpniio.
//
// libpniio is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 2 of the License, or
// (at your option) any later version.
//
// libpniio 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with libpniio.  If not, see <http://www.gnu.org/licenses/>.
// ===========================================================================
// Created on: Jul 5, 2013
//     Author: Eugen Wintersberger <eugen.wintersberger@desy.de>
//
#pragma once

#include <pni/core/types.hpp>
#include <pni/core/arrays/slice.hpp>
#include <vector>
#include "../nxobject.hpp"
#include "../nxobject_traits.hpp"

namespace pni{
namespace io{
namespace nx{

    template<
             template<nximp_code> class OTYPE,
             nximp_code IMPID,
             typename ATYPE
            >
    void read(const OTYPE<IMPID> &o,ATYPE &a)
    {
        typedef nxobject_trait<IMPID> trait_type;
        typedef typename trait_type::field_type field_type;
        typedef typename trait_type::attribute_type attribute_type;

        static_assert(std::is_same<OTYPE<IMPID>,field_type>::value || 
                      std::is_same<OTYPE<IMPID>,attribute_type>::value,
                      "WRITE CAN ONLY BE USED WITH FIELDS AND "
                      "ATTRIBUTES!");
        o.read(a);
    }

    //------------------------------------------------------------------------
    template<
             template<nximp_code> class OTYPE,
             nximp_code IMPID,
             typename ATYPE,
             typename ...ITYPES
            >
    void read(const OTYPE<IMPID> &o,ATYPE &a,ITYPES ...indices)
    {
        typedef nxobject_trait<IMPID> trait_type;
        typedef typename trait_type::field_type field_type;
        typedef typename trait_type::attribute_type attribute_type;

        static_assert(std::is_same<OTYPE<IMPID>,field_type>::value || 
                      std::is_same<OTYPE<IMPID>,attribute_type>::value,
                      "WRITE CAN ONLY BE USED WITH FIELDS AND "
                      "ATTRIBUTES!");

        o(indices...).read(a);
    }
    
    //------------------------------------------------------------------------
    template<
             typename ATYPE,
             typename GTYPE,
             typename FTYPE,
             typename ATTYPE,
             typename LTYPE
            > 
    class read_visitor : public boost::static_visitor<void>
    {
        public: 
            typedef std::vector<pni::core::slice> selection_t;
        private:
            ATYPE &_data;
            selection_t _selection;
        public:
            using result_type = void;
            using group_type = GTYPE;
            using field_type = FTYPE;
            using attribute_type = ATTYPE;
            using link_type = LTYPE;

            //-----------------------------------------------------------------
            read_visitor(ATYPE &data,const selection_t &s=selection_t()):
                _data(data),
                _selection(s)
            {}

            //-----------------------------------------------------------------
            result_type operator()(const group_type &) const
            {
                using namespace pni::core;
                throw type_error(EXCEPTION_RECORD,
                        "One cannot read data to a group object!");
            }

            //-----------------------------------------------------------------
            result_type operator()(const field_type &f) const
            {
                if(_selection.size())
                    f(_selection).read(_data);
                else
                    f.read(_data);
            }

            //-----------------------------------------------------------------
            result_type operator()(const attribute_type &a) const
            {
                if(_selection.size())
                    a(_selection).read(_data);
                else
                    a.read(_data);
            }
            
            //-----------------------------------------------------------------
            result_type operator()(const link_type &) const
            {
                using namespace pni::core;
                throw type_error(EXCEPTION_RECORD,
                        "Cannot read data from a link!");
            }
    };

    //------------------------------------------------------------------------
    template<typename ATYPE,
             typename GTYPE,
             typename FTYPE,
             typename ATTYPE,
             typename LTYPE,
             typename ...ITYPES 
            > 
    void read(const nxobject<GTYPE,FTYPE,ATTYPE,LTYPE> &o,ATYPE &a,ITYPES ...indices)
    {
        using visitor_t = read_visitor<ATYPE,GTYPE,FTYPE,ATTYPE,LTYPE>;
        std::vector<pni::core::slice> sel{pni::core::slice(indices)...};
        visitor_t visitor(a,sel);
        return boost::apply_visitor(visitor,o);
    }

    //------------------------------------------------------------------------
    template<typename ATYPE,
             typename GTYPE,
             typename FTYPE,
             typename ATTYPE,
             typename LTYPE,
             typename ...ITYPES 
            > 
    void read(nxobject<GTYPE,FTYPE,ATTYPE,LTYPE> &&o,ATYPE &a,ITYPES ...indices)
    {
        using visitor_t = read_visitor<ATYPE,GTYPE,FTYPE,ATTYPE,LTYPE>;
        std::vector<pni::core::slice> sel{pni::core::slice(indices)...};
        visitor_t visitor(a,sel);
        return boost::apply_visitor(visitor,o);
    }

    //------------------------------------------------------------------------
    template<
             typename ATYPE,
             typename GTYPE,
             typename FTYPE,
             typename ATTYPE,
             typename LTYPE
            >
    void read(const nxobject<GTYPE,FTYPE,ATTYPE,LTYPE> &o,ATYPE &a,
              const std::vector<pni::core::slice> &sel)
    {
        using visitor_t = read_visitor<ATYPE,GTYPE,FTYPE,ATTYPE,LTYPE>;
        visitor_t visitor(a,sel);
        return boost::apply_visitor(visitor,o);
    }

    //------------------------------------------------------------------------
    template<
             typename ATYPE,
             typename GTYPE,
             typename FTYPE,
             typename ATTYPE,
             typename LTYPE
            >
    void read(nxobject<GTYPE,FTYPE,ATTYPE,LTYPE> &&o,ATYPE &a,
                       const std::vector<pni::core::slice> &sel)
    {
        using visitor_t = read_visitor<ATYPE,GTYPE,FTYPE,ATTYPE,LTYPE>;
        visitor_t visitor(a,sel);
        return boost::apply_visitor(visitor,o);
    }
//end of namespace
}
}
}