fits_io_mpl.h

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// -*- lsst-c++ -*-
/*
 * LSST Data Management System
 * Copyright 2008, 2009, 2010 LSST Corporation.
 *
 * This product includes software developed by the
 * LSST Project (http://www.lsst.org/).
 *
 * This program 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 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 LSST License Statement and
 * the GNU General Public License along with this program.  If not,
 * see <http://www.lsstcorp.org/LegalNotices/>.
 */

#ifndef LSST_AFW_IMAGE_fits_io_mpl_h_INCLUDED
#define LSST_AFW_IMAGE_fits_io_mpl_h_INCLUDED

#include "boost/mpl/for_each.hpp"
#include "boost/mpl/vector.hpp"

#include "lsst/geom.h"
#include "lsst/afw/fits.h"
#include "lsst/afw/image/fits/fits_io.h"
#include "lsst/afw/image/Image.h"

namespace lsst {
namespace afw {
namespace image {

namespace {
struct found_type : public std::exception {};  // type to throw when we've read our data

template <typename ImageT, typename ExceptionT>
class try_fits_read_array {
public:
    try_fits_read_array(fits::Fits& fitsfile, ndarray::Array<typename ImageT::Pixel, 2, 2>& array,
                        lsst::geom::Point2I& xy0, daf::base::PropertySet& metadata,
                        lsst::geom::Box2I const& bbox, ImageOrigin const origin)
            : _fitsfile(&fitsfile),
              _array(array),
              _xy0(xy0),
              _metadata(metadata),
              _bbox(bbox),
              _origin(origin) {}

    // read directly into the desired type if the file's the same type
    void operator()(typename ImageT::Pixel) {
        try {
            fits_read_array(*_fitsfile, _array, _xy0, _metadata, _bbox, _origin);
            throw ExceptionT();  // signal that we've succeeded
        } catch (fits::FitsTypeError const&) {
            // ah well.  We'll try another image type
        }
    }

    template <typename OtherPixel>
    void operator()(OtherPixel) {  // read and convert into the desired type
        try {
            ndarray::Array<OtherPixel, 2, 2> array;
            fits_read_array(*_fitsfile, array, _xy0, _metadata, _bbox, _origin);
            // copy and convert
            _array = ndarray::allocate(array.getShape());
            _array.deep() = array;
            throw ExceptionT();  // signal that we've succeeded
        } catch (fits::FitsTypeError const&) {
            // pass
        }
    }

private:
    fits::Fits* _fitsfile;
    ndarray::Array<typename ImageT::Pixel, 2, 2>& _array;
    lsst::geom::Point2I& _xy0;
    daf::base::PropertySet& _metadata;
    lsst::geom::Box2I const& _bbox;
    ImageOrigin _origin;
};

}  // namespace

template <typename supported_fits_types, typename ImageT>
void fits_read_image(fits::Fits& fitsfile, ImageT& img, lsst::daf::base::PropertySet& metadata,
                     lsst::geom::Box2I const& bbox = lsst::geom::Box2I(), ImageOrigin const origin = PARENT) {
    ndarray::Array<typename ImageT::Pixel, 2, 2> array;
    lsst::geom::Point2I xy0;
    fitsfile.checkCompressedImagePhu();
    try {
        try_fits_read_array<ImageT, found_type> reader{fitsfile, array, xy0, metadata, bbox, origin};
        reader.operator()(typename ImageT::Pixel());  // attempt first the type we were explicitly asked for
        boost::mpl::for_each<supported_fits_types>(reader);
    } catch (found_type&) {
        img = ImageT(array, false, xy0);
        return;
    }
    throw LSST_FITS_EXCEPT(fits::FitsError, fitsfile, "FITS file does not have one of the expected types");
}

template <typename supported_fits_types, typename ImageT>
void fits_read_image(fits::Fits& fitsfile, ImageT& img,
                     std::shared_ptr<lsst::daf::base::PropertySet> metadata =
                             std::shared_ptr<lsst::daf::base::PropertySet>(),
                     lsst::geom::Box2I const& bbox = lsst::geom::Box2I(), ImageOrigin const origin = PARENT) {
    lsst::daf::base::PropertySet metadata_s;
    fits_read_image<supported_fits_types, ImageT>(fitsfile, img, (metadata ? *metadata : metadata_s), bbox,
                                                  origin);
}
}  // namespace image
}  // namespace afw
}  // namespace lsst
#endif  // !LSST_AFW_IMAGE_fits_io_mpl_h_INCLUDED