gzip_input_source.hpp

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#ifndef GENESIS_UTILS_IO_GZIP_INPUT_SOURCE_H_
#define GENESIS_UTILS_IO_GZIP_INPUT_SOURCE_H_

/*
    Genesis - A toolkit for working with phylogenetic data.
    Copyright (C) 2014-2020 Lucas Czech and HITS gGmbH

    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 GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.

    Contact:
    Lucas Czech <lucas.czech@h-its.org>
    Exelixis Lab, Heidelberg Institute for Theoretical Studies
    Schloss-Wolfsbrunnenweg 35, D-69118 Heidelberg, Germany
*/

#include "genesis/utils/io/base_input_source.hpp"

#include <memory>
#include <string>

namespace genesis {
namespace utils {

// =================================================================================================
//     Gzip Input Source
// =================================================================================================

class GzipInputSource final : public BaseInputSource
{
public:

    // -------------------------------------------------------------
    //     Typedefs and Enums
    // -------------------------------------------------------------

    enum class Format
    {
        kAutomatic,

        kGzip,

        kZlib,

        kDeflate
    };

    // -------------------------------------------------------------
    //     Constructors and Rule of Five
    // -------------------------------------------------------------

    explicit GzipInputSource(
        std::shared_ptr<BaseInputSource> input_source,
        Format format = Format::kAutomatic
    );

    GzipInputSource( GzipInputSource const& ) = delete;
    GzipInputSource( GzipInputSource&& )      = default;

    GzipInputSource& operator= ( GzipInputSource const& ) = delete;
    GzipInputSource& operator= ( GzipInputSource&& )      = default;

    ~GzipInputSource() override;

    // -------------------------------------------------------------
    //     Overloaded Internal Members
    // -------------------------------------------------------------

private:

    static const size_t BlockLength = 1 << 20;

    size_t read_( char* buffer, size_t size ) override;

    std::string source_name_() const override
    {
        return format_name_ + "-compressed " + input_source_->source_name();
    }

    std::string source_string_() const override;

    int get_format_( Format format ) const;

    std::string translate_format_( Format format ) const;

    // -------------------------------------------------------------
    //     Member Variables
    // -------------------------------------------------------------

    std::shared_ptr<BaseInputSource> input_source_;
    std::string format_name_;

    // We want to avoid including the zlib header in this header,
    // because it totally pollutes everything.
    // So, we use a PIMPL-like data hiding technique for the zlib related members.
    struct ZlibData;

    // Store the implementation and the implementation's deleter as well.
    // Deleter is a pointer to a function with signature `void func(ZlibData *)`.
    // This way, we can use the default move constructor and default move assignment
    // for this class without implementing them on our own.
    std::unique_ptr<ZlibData, void (*)(ZlibData *)> zlib_data_;

};

} // namespace utils
} // namespace genesis

#endif // include guard