istream1.cpp

C标准库源代码

/***
* istream1.cpp - non-core definitions for istream & istream_withassign classes
*
*       Copyright (c) 1991-1997, Microsoft Corporation.  All rights reserved.
*
*Purpose:
*       Definitions of non-core member functions for istream and
*       istream_withassign classes.
*       [AT&T C++]
*
*******************************************************************************/

#include <cruntime.h>
#include <internal.h>
#include <stdlib.h>
#include <iostream.h>
#pragma hdrstop

istream& istream::operator>>(streambuf* _sbuf)
{
    int c;
    if (ipfx(0))
        {
        while ((c=bp->sbumpc())!=EOF)
            {
            if (_sbuf->sputc(c)==EOF)
                {
                state |= ios::failbit;
                }
            }
        isfx();
        }
return *this;
}


// unformatted input functions

istream& istream::get( streambuf& sbuf, char delim)
{
    int c;
    if (ipfx(1))        // resets x_gcount
        {
        while ((c  = bp->sgetc())!=delim)
            {
            if (c==EOF)  // stop if EOF encountered
                {
                state |= ios::eofbit;
                break;
                }
            bp->stossc();       // advance get pointer
            x_gcount++;         // and increment count

            if (sbuf.sputc(c)==EOF)
                state |= ios::failbit;
            }
        isfx();
        }
    return *this;
}

istream& istream::seekg(streampos _strmp)
{
    lockbuf();
    if (bp->seekpos(_strmp, ios::in)==EOF)
        {
        clear(state | failbit);
        }
    unlockbuf();
    return(*this);
}

istream& istream::seekg(streamoff _strmf, seek_dir _sd)
{
    lockbuf();
    if (bp->seekoff(_strmf, _sd, ios::in)==EOF)
        clear(state | failbit);
    unlockbuf();
    return(*this);
}

streampos istream::tellg()
{
    streampos retval;
    lockbuf();
    if ((retval=bp->seekoff(streamoff(0), ios::cur, ios::in))==EOF)
        clear(state | failbit);
    unlockbuf();
    return(retval);
}