DatasetFiller.hpp

/* Copyright 2018-2025 Franz Poeschel, Axel Huebl
 *
 * This file is part of openPMD-api.
 *
 * openPMD-api is free software: you can redistribute it and/or modify
 * it under the terms of of either the GNU General Public License or
 * the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * openPMD-api 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 and the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License
 * and the GNU Lesser General Public License along with openPMD-api.
 * If not, see <http://www.gnu.org/licenses/>.
 */
 
#pragma once
 
#include "openPMD/Dataset.hpp"
#include <memory>
#include <random>
 
namespace openPMD
{
template <typename T>
class DatasetFiller
{
protected:
    Extent::value_type m_numberOfItems;
 
public:
    using resultType = T;
 
    explicit DatasetFiller(Extent::value_type numberOfItems = 0);

    virtual ~DatasetFiller() = default;

    virtual std::shared_ptr<T> produceData() = 0;

    virtual void setNumberOfItems(Extent::value_type numberOfItems) = 0;
};
 
template <typename T>
DatasetFiller<T>::DatasetFiller(Extent::value_type numberOfItems)
    : m_numberOfItems(numberOfItems)
{}
 
template <typename DF>
class SimpleDatasetFillerProvider
{
public:
    using resultType = typename DF::resultType;
 
private:
    std::shared_ptr<DF> m_df;
 
    template <typename T, typename Dummy = void>
    struct Helper
    {
        std::shared_ptr<DatasetFiller<T>> operator()(std::shared_ptr<DF> &)
        {
            throw std::runtime_error(
                "Can only create data of type " +
                datatypeToString(determineDatatype<resultType>()));
        }
    };
 
    template <typename Dummy>
    struct Helper<resultType, Dummy>
    {
        std::shared_ptr<DatasetFiller<resultType>>
        operator()(std::shared_ptr<DF> &df)
        {
            return df;
        }
    };
 
public:
    explicit SimpleDatasetFillerProvider(DF df)
        : m_df{std::make_shared<DF>(std::move(df))}
    {}
 
    template <typename T>
    std::shared_ptr<DatasetFiller<T>> operator()()
    {
        Helper<T> h;
        return h(m_df);
    }
};
 
} // namespace openPMD