dectris_reader.hpp

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//
// (c) Copyright 2011 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: Apr 23, 2012
//     Author: Eugen Wintersberger <eugen.wintersberger@desy.de>
//
//

#pragma once

#include<iostream>
#include<fstream>
#include<vector>

#include "../image_info.hpp"
#include "types.hpp"


namespace pni{
namespace io{
namespace cbf{
    
    //1
    class dectris_reader
    {
        public:
            static std::streampos read_header(std::ifstream &is,
                    std::vector<pni::io::image_info> &info,compression_id &ct);

            //-----------------------------------------------------------------
            template<
                     typename CBFT,
                     typename CTYPE
                    >
            static void read_data_byte_offset(std::ifstream &is,
                                              const pni::io::image_info &info,
                                              CTYPE &data);


    };

    //-------------------------------------------------------------------------
    template<
             typename CBFT,
             typename CTYPE
            >
    void dectris_reader::read_data_byte_offset(std::ifstream &is,
                                 const pni::io::image_info &, CTYPE &data)
    {
        using namespace pni::core;
        //unsigned long i;
        //size_t ecnt = 0; // element counter
        CBFT buffer = 0; // single element buffer

        //initializing the container with 0
        std::fill(data.begin(),data.end(),0);
        typename CTYPE::iterator iter = data.begin();
        typename CTYPE::value_type v_old = 0;

        for(typename CTYPE::value_type &v: data)
        {
            v = v_old; //set the new value to the previous

            buffer = 0; //reset the read buffer
            //read one byte from the stream an throw an exception in case of an
            //error
            try { is.read((char *)(&buffer),1); }
            catch(...)
            {
                throw file_error(EXCEPTION_RECORD,
                        "Error reading 1Byte from the CBF stream!");
            }

            if (((unsigned char) buffer) != 0x80)
            {
                v += (char) buffer;
                v_old = v;
                continue;
            }
          
            //read two byte from the stream and throw an exception in case of an
            //error
            try { is.read((char *) (&buffer), 2); }
            catch(...)
            {
                throw file_error(EXCEPTION_RECORD,
                        "Error reading 2Byte from the CBF stream!");
            }

            if (((unsigned short) buffer) != 0x8000) 
            {
                v += (short) buffer;
                v_old = v;
                continue;
            }

            //read 4 byte from the stream and throw an exception in the case of
            //an error
            try { is.read((char*) (&buffer), 4); }
            catch(...)
            {
                throw file_error(EXCEPTION_RECORD,
                        "Error reading 4byte from the CBF stream!");
            }

            if (((unsigned int) buffer) != 0x800000) 
            {
                v += (int) buffer;
                v_old = v;
                continue;
            }

        }

    }

//end of namespace
}
}
}