presageCallback.h

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/******************************************************
 *  Presage, an extensible predictive text entry system
 *  ---------------------------------------------------
 *
 *  Copyright (C) 2008  Matteo Vescovi <matteo.vescovi@yahoo.co.uk>

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


#ifndef PRESAGE_CALLBACK
#define PRESAGE_CALLBACK

#ifdef __cplusplus
extern "C" {
#endif

    typedef const char* (*_presage_callback_get_past_stream)   (void*);
    typedef const char* (*_presage_callback_get_future_stream) (void*);

#ifdef __cplusplus
}
#endif


#ifdef __cplusplus
#ifndef _MSC_VER

#include <string>
#include <sstream>

class PresageCallback {
public:
    virtual ~PresageCallback() { };

    virtual std::string get_past_stream() const = 0;
    virtual std::string get_future_stream() const = 0;

protected:
    PresageCallback() { };

};


class LegacyPresageCallback : public PresageCallback {
public:
    LegacyPresageCallback() { }
    ~LegacyPresageCallback() { }
    
    std::string get_past_stream() const { return m_stream; }
    std::string get_future_stream() const { return m_empty; }

    void update(std::string str) { for (size_t sz = 0; sz < str.size(); sz++) { update(str[sz]); } }

private:
    void update(int character) { 
        if (character == '\b'
            && ! m_stream.empty()) {
            m_stream.erase(m_stream.end() - 1);
        } else {
            m_stream.push_back(character);
        }
    }

    std::string m_stream;
    const std::string m_empty;
};

#endif /* _MSC_VER */
#endif /* _cplusplus */

#endif /* PRESAGE_CALLBACK */