Reactor.hh

/*
    autojson: A JSON parser base on the automaton provided by json.org
    Copyright (C) 2014  Wan Wai Ho

    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 version 2
    of the License.

    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, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
    02110-1301, USA.
*/

#ifndef REACTOR_HH_INCLUDED
#define REACTOR_HH_INCLUDED

#include "JSON_checker.h"
#include "LexicalCast.hh"

#include <string>

namespace ajs {

class ParseState;

class Reactor
{
public:
    virtual ParseState On(ParseState& s, JSON_event event, const char *data, std::size_t len) = 0;
    virtual Reactor* Clone() const = 0;
};

struct ParseState
{
    Reactor *reactor;
    void    *dest;
};

template <typename DestType, typename T>
class SaveToMember : public Reactor
{
public :
    SaveToMember(T DestType::*member) : m_member(member)
    {
    }

    ParseState On(ParseState& s, JSON_event event, const char *data, std::size_t len) override
    {
        DestType *dest = reinterpret_cast<DestType*>(s.dest);
        (dest->*m_member) = lexical_cast<T>(data, len);
        return s;
    }

    SaveToMember* Clone() const override
    {
        return new SaveToMember(m_member);
    }

private :
    T DestType::*m_member;
};

} // end of namespace

#endif