void CompressedFitsWriter::writeDrsCalib ( )

private

Write the drs calibration to disk, if any.

Definition at line 741 of file fitsCompressor.cc.

References _drsCalibData, _emptyBlock, CompressedFitsFile::_file, Checksum::add(), end, i, str, Checksum::str(), and Checksum::val().

Referenced by writeHeader().

{
    //if file was not loaded, ignore
    if (_drsCalibData == NULL)
        return;
    uint64_t whereDidIStart = _file.tellp();
    vector<HeaderEntry> header;
    header.push_back(HeaderEntry("XTENSION", "'BINTABLE'          ", "binary table extension"));
    header.push_back(HeaderEntry("BITPIX"  , 8                     , "8-bit bytes"));
    header.push_back(HeaderEntry("NAXIS"   , 2                     , "2-dimensional binary table"));
    header.push_back(HeaderEntry("NAXIS1"  , 1024*1440*2           , "width of table in bytes"));
    header.push_back(HeaderEntry("NAXIS2"  , 1                     , "number of rows in table"));
    header.push_back(HeaderEntry("PCOUNT"  , 0                     , "size of special data area"));
    header.push_back(HeaderEntry("GCOUNT"  , 1                     , "one data group (required keyword)"));
    header.push_back(HeaderEntry("TFIELDS" , 1                     , "number of fields in each row"));
    header.push_back(HeaderEntry("CHECKSUM", "'0000000000000000'  ", "Checksum for the whole HDU"));
    header.push_back(HeaderEntry("DATASUM" ,  "         0"         , "Checksum for the data block"));
    header.push_back(HeaderEntry("EXTNAME" , "'ZDrsCellOffsets'    ", "name of this binary table extension"));
    header.push_back(HeaderEntry("TTYPE1"  , "'OffsetCalibration' ", "label for field   1"));
    header.push_back(HeaderEntry("TFORM1"  , "'1474560I'          ", "data format of field: 2-byte INTEGER"));

    for (uint32_t i=0;i<header.size();i++)
        _file.write(header[i].fitsString().c_str(), 80);
    //End the header
    _file.write("END                                                                             ", 80);
    long here = _file.tellp();
    if (here%2880)
        _file.write(_emptyBlock.c_str(), 2880 - here%2880);
    //now write the data itself
    int16_t* swappedBytes = new int16_t[1024];
    Checksum checksum;
    for (int32_t i=0;i<1440;i++)
    {
        memcpy(swappedBytes, &(_drsCalibData[i*1024]), 2048);
        for (int32_t j=0;j<2048;j+=2)
        {
            int8_t inter;
            inter = reinterpret_cast<int8_t*>(swappedBytes)[j];
            reinterpret_cast<int8_t*>(swappedBytes)[j] = reinterpret_cast<int8_t*>(swappedBytes)[j+1];
            reinterpret_cast<int8_t*>(swappedBytes)[j+1] = inter;
        }
        _file.write(reinterpret_cast<char*>(swappedBytes), 2048);
        checksum.add(reinterpret_cast<char*>(swappedBytes), 2048);
    }
    uint64_t whereDidIStop = _file.tellp();
    delete[] swappedBytes;
    //No need to pad the data, as (1440*1024*2)%2880==0

    //calculate the checksum from the header
    ostringstream str;
    str << checksum.val();
    header[9] = HeaderEntry("DATASUM", str.str(), "Checksum for the data block");
    for (vector<HeaderEntry>::iterator it=header.begin();it!=header.end(); it++)
        checksum.add(it->fitsString().c_str(), 80);
    string   end("END                                                                             ");
    string space("                                                                                ");
    checksum.add(end.c_str(), 80);
    int headerRowsLeft = 36 - (header.size() + 1)%36;
    for (int i=0;i<headerRowsLeft;i++)
        checksum.add(space.c_str(), 80);
    //udpate the checksum keyword
    header[8] = HeaderEntry("CHECKSUM", checksum.str(), "Checksum for the whole HDU");
    //and eventually re-write the header data
    _file.seekp(whereDidIStart);
    for (uint32_t i=0;i<header.size();i++)
        _file.write(header[i].fitsString().c_str(), 80);
    _file.seekp(whereDidIStop);
}

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