refill.c

VXWORKS源代码

/* refill.c - file for stdio.h */

/* Copyright 1992 Wind River Systems, Inc. */

/*
modification history
--------------------
01b,20sep92,smb  documentation additions
01a,29jul92,jcf  Flush only the current fp.
	   +smb  taken from UCB stdio
*/

/*
DESCRIPTION
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.

INCLUDE FILE: stdio.h, error.h, stdlib.h

SEE ALSO: American National Standard X3.159-1989

NOMANUAL
*/

#include "vxWorks.h"
#include "stdio.h"
#include "errno.h"
#include "stdlib.h"
#include "private/stdioP.h"


/******************************************************************************
*
* lflush - internal routine.
* 
* INCLUDE: stdio.h 
*
* RETURNS: 
* NOMANUAL
*/

LOCAL int lflush
    (
    FILE *fp
    )
    {
    if ((fp->_flags & (__SLBF | __SWR)) == (__SLBF | __SWR))
	return (__sflush (fp));

    return (0);
    }

/******************************************************************************
*
* __srefill - refill a stdio buffer.
* 
* INCLUDE: stdio.h 
*
* RETURNS: EOF on eof or error, 0 otherwise.
* NOMANUAL
*/

int __srefill
    (
    FAST FILE *fp
    )
    {
    fp->_r = 0;		/* largely a convenience for callers */

    /* SysV does not make this test; take it out for compatibility */

    if (fp->_flags & __SEOF)
	return (EOF);

    /* if not already reading, have to be reading and writing */

    if ((fp->_flags & __SRD) == 0) 
	{
	if ((fp->_flags & __SRW) == 0) 
	    {
	    errno = EBADF;
	    return (EOF);
	    }

	if (fp->_flags & __SWR)			/* switch to reading */
	    {
	    if (__sflush (fp))
		return (EOF);

	    fp->_flags 		&= ~__SWR;
	    fp->_w		 = 0;
	    fp->_lbfsize	 = 0;
	    }
	fp->_flags |= __SRD;
	}
    else 
	{
	/*
	 * We were reading.  If there is an ungetc buffer,
	 * we must have been reading from that.  Drop it,
	 * restoring the previous buffer (if any).  If there
	 * is anything in that buffer, return.
	 */

	if (HASUB(fp)) 
	    {
	    FREEUB(fp);

	    if ((fp->_r = fp->_ur) != 0) 
		{
		fp->_p = fp->_up;

		return (0);
		}
	    }
	}

    if (fp->_bf._base == NULL)
	__smakebuf (fp);

    /*
     * Before reading from a line buffered or unbuffered file,
     * flush all line buffered output files, per the ANSI C
     * standard.
     */

    if (fp->_flags & (__SLBF|__SNBF))
	    lflush(fp);			/* flush at least current fp */

	    /* XXX lflush(stdin);		Someday we could flush these */
	    /* XXX lflush(stdout);		Someday we could flush these */
	    /* XXX lflush(stderr);		Someday we could flush these */

    fp->_p	= fp->_bf._base;
    fp->_r	= __sread (fp, (char *)fp->_p, fp->_bf._size);
    fp->_flags &= ~__SMOD;		/* buffer contents are again pristine */

    if (fp->_r <= 0) 
	{
	if (fp->_r == 0)
	    fp->_flags |= __SEOF;
	else 
	    {
	    fp->_r = 0;
	    fp->_flags |= __SERR;
	    }

	return (EOF);
	}

    return (0);
    }