ZBuffer.h

/*
 * Copyright (C) 2015 by Marc Boris Duerner
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * As a special exception, you may use this file as part of a free
 * software library without restriction. Specifically, if other files
 * instantiate templates or use macros or inline functions from this
 * file, or you compile this file and link it with other files to
 * produce an executable, this file does not by itself cause the
 * resulting executable to be covered by the GNU General Public
 * License. This exception does not however invalidate any other
 * reasons why the executable file might be covered by the GNU Library
 * General Public License.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */
 
#ifndef PT_ZBUFFER_H
#define PT_ZBUFFER_H
 
#include <Pt/Api.h>
#include <Pt/StreamBuffer.h>
#include <ios>
#include <cstddef>
 
typedef struct z_stream_s z_stream;
 
namespace Pt {

class PT_API ZBuffer : public BasicStreamBuffer<char>
{
    public:
        enum Format
        {
            Zlib = 0, 
            Gzip      
        };

        ZBuffer(Format fmt = Zlib);

        ZBuffer(std::ios& ios, Format fmt = Zlib);

        virtual ~ZBuffer();

        void attach(std::ios& target);

        void detach();

        void discard();

        void reset();

        void reset(std::ios& target);

        void finish();

        std::size_t zcount() const { return _zcount; }

        std::streamsize import(std::streamsize maxImport = 0);
 
        std::streamsize import(const char* data, std::streamsize size);
 
    protected:
        // inheritdoc
        virtual std::streamsize showmanyc();
 
        // inheritdoc
        virtual std::streamsize showfull();
 
        // inheritdoc
        virtual int sync();
 
        // inheritdoc
        virtual int_type underflow();
 
        // inheritdoc
        virtual int_type overflow(int_type ch);
 
    private:
        void inflateBuffer();
 
    private:
        std::ios* _target;
        z_stream* _zread;
        z_stream* _zwrite;
        Format _format;
 
        static const int _pbmax = 4;
        static const int _bufmax = 4096;
        char _ibuf[_bufmax];
        char _obuf[_bufmax];
 
        static const int _zbufmax = 4096;
        char _zibuf[_zbufmax];
        int _zibufsize;
        char _zobuf[_zbufmax];
 
        std::size_t _zcount;
};
 
} // namespace Pt
 
#endif // PT_ZBUFFER_H