streaming_base.hpp

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/*
 * Copyright (C) 2007,2008   Alex Shulgin
 *
 * This file is part of png++ the C++ wrapper for libpng.  PNG++ is free
 * software; the exact copying conditions are as follows:
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 *
 * 3. The name of the author may not be used to endorse or promote products
 * derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
 * NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#ifndef PNGPP_STREAMING_BASE_HPP_INCLUDED
#define PNGPP_STREAMING_BASE_HPP_INCLUDED

#include <cassert>
#include "image_info.hpp"
#include "pixel_traits.hpp"

namespace png
{

    class def_image_info_holder
    {
    public:
        def_image_info_holder(image_info const& info)
            : m_info(info)
        {
        }

        image_info& get_info()
        {
            return m_info;
        }

    private:
        image_info m_info;
    };

    class image_info_ref_holder
    {
    public:
        image_info_ref_holder(image_info& info)
            : m_info(info)
        {
        }

        image_info& get_info()
        {
            return m_info;
        }

    private:
        image_info& m_info;
    };

    template< typename pixel, class info_holder >
    class streaming_base
    {
    public:
        typedef pixel_traits< pixel > traits;

        explicit streaming_base(image_info& info)
            : m_info_holder(info)
        {
        }

        streaming_base(size_t width, size_t height)
            : m_info_holder(make_image_info< pixel >())
        {
            get_info().set_width(width);
            get_info().set_height(height);
        }

        image_info const& get_info() const
        {
            return m_info_holder.get_info();
        }

    protected:
        void reset(size_t /*pass*/)
        {
            // nothing to do in the most general case
        }

        image_info& get_info()
        {
            return m_info_holder.get_info();
        }

        info_holder m_info_holder;
    };

} // namespace png

#endif // PNGPP_STREAMING_BASE_HPP_INCLUDED