Pccts/h/DLG_stream_input.h

	DLG_stream_input.h revision 4fd606d1f5abe38e1f42c38de1d2e895166bd0f4

/************************************************************/
/*                                                          */
/*      Predefined char stream: Input from (c++) stream.    */
/*                                                          */
/* By Hubert Holin (Hubert.Holin@Bigfoot.com), 1998.        */
/*                                                          */
/* This is completely free stuff, do whatever you want with */
/* it (but then, I will take no responsability for whatever */
/* may happen if you do either... caveat emptor!).          */
/*                                                          */
/************************************************************/

#ifndef _DLG_STREAM_INPUT_H
#define _DLG_STREAM_INPUT_H

#include "pccts_istream.h"

PCCTS_NAMESPACE_STD

#ifndef DLGX_H
#include "DLexerBase.h"
#endif


// NOTES:   The semantics of the copy constructor
//          and the affectation operator may be unwaranted...
//          and the stream may not be reset.
//
//          It would have been so much nicer for nextChar()
//          to throw (of for the DLGInputStream to change status)
//          upon hiting EOF than to return an "int"...

template    <
                class E,
                class T = ::std::char_traits<E>
            >
class DLG_stream_input : public DLGInputStream
{
public:

                        DLG_stream_input(::std::basic_istream<E,T> * p_input_stream)
    :   input(p_input_stream)
    {
        // nothing to do!
    };

                        DLG_stream_input(const DLG_stream_input & a_recopier)
    :   input(a_recopier.input)
    {
        // nothing to do!
    };

    virtual             ~DLG_stream_input()
    {
        this->purge();  // bloody templarized lookup...
    };

    DLG_stream_input    operator = (const DLG_stream_input & a_affecter)
    {
        if (this != &a_affecter)
        {
            input = a_affecter.input;
        }

        return(*this);
    };

    virtual int         nextChar()
    {
        E   extracted_stuff;

        input->get(extracted_stuff);

        if  (*input)
        {
            return(int(extracted_stuff));
        }
        else
        {
            return(EOF);
        }
    };

protected:

    ::std::basic_istream<E,T> * input;

private:

    void    purge()
    {
        // nothing to do!
    };
};

#endif /* _DLG_STREAM_INPUT_H */