grid/gridPoint.h

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/**
 *  @file      gridPoint.h
 *  @brief     Definitions of the GridPoint and the IORecord (input/output) class.
 *  @author    Mikica Kocic
 *  @copyright GNU General Public License (GPLv3).
 */

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/** @defgroup g4 Grid driver                                                           */
/////////////////////////////////////////////////////////////////////////////////////////
                                                                                   /*@{*/
/** A set of variables that is tracked on a grid point.
 */
typedef Real GridPoint[ GFCNT ];

/** A wrapper for @ref GridPoint so that @ref GridPoint's array of fields
 *  can be treated as a compound object when reading/writing.
 */
class IORecord
{
    Real* gridSlice; //!< The array of fields values at the grid point
public:

    IORecord( GridPoint& gp )
        : gridSlice( gp )
    {}

    /** Resets all the variables to a specific value (by default NAN).
     */
    void clear( Real value = NAN )
    {
        // We assume that Reals are tightly packed in the struture.
        auto len = sizeof(GridPoint) / sizeof(Real);
        for( Real* fp = gridSlice; len > 0; --len, ++fp ) {
            *fp = value;
        }
    }

    /** Reads the variable values from a file stream.
     */
    bool read( FILE* inf, bool isBinary, const std::vector<Int>& input )
    {
        clear ();

        auto len = input.size();
        Real data[ len ];

        if( isBinary )
        {
            if( len != fread( data, sizeof(data[0]), len, inf ) ) {
                std::cerr << "Error: Premature end of grid." << std::endl;
                return false;
            }
        }
        else
        {
            char line[ input.size() * 80 ] = {0};
            do {
                if( ! fgets( line, sizeof(line)-1, inf ) ) {
                    std::cerr << "Error: Premature end of grid." << std::endl;
                    return false;
                }
            } while( line[0] == '*' ); // Ignore comments (starting with '*')

            size_t count = sscanf_Real( line, data, len );
            if( count != len ) {
                std::cerr << "Error: Wrong number of variables." << std::endl;
                return false;
            }
        }

        for( size_t i = 0; i < len; ++i ) {
            gridSlice[ input[i] ] = data[i];
        }

        return true;
    }

    /** Writes the variable values to a file stream.
     *  @warning The order of fields in data[] (output data record)
     *           should match the Mathematica notebook!
     */
    void write( FILE* outf, bool isBinary, const std::vector<Int> output )
    {
        auto len = output.size(); /// @todo fld::output should be dynamic in ID class
        Real data[ len ];

        for( size_t i = 0; i < len; ++i ) {
            data[i] = gridSlice[ output[i] ];
        }

        if( isBinary ) {
            fwrite( data, sizeof(data[0]), len, outf );
        }
        else {
            for( size_t i = 0; i < len; ++i ) {
                if ( i > 0 ) fputs( "\t", outf );
                fputReal( outf,  data[i] );
            }
            fputs( "\n", outf );
        }
    }
};
                                                                                   /*@}*/
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