wbuf.c

vxworks libc库源代码

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

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

/*
modification history
--------------------
01b,20sep92,smb  documentation additions
01a,29jul92,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

SEE ALSO: American National Standard X3.159-1989

NOMANUAL
*/

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


/******************************************************************************
*
* __swbuf - 
* 
* Write the given character into the (probably full) buffer for
* the given file.  Flush the buffer out if it is or becomes full,
* or if c=='\n' and the file is line buffered.
*
* INCLUDE: stdio.h 
*
* RETURNS: 
* NOMANAUL
*/

int __swbuf
    (
    FAST int	c,
    FAST FILE *	fp
    )
    {
    FAST int    n;

    /*
     * In case we cannot write, or longjmp takes us out early,
     * make sure _w is 0 (if fully- or un-buffered) or -_bf._size
     * (if line buffered) so that we will get called again.
     * If we did not do this, a sufficient number of putc()
     * calls might wrap _w from negative to positive.
     */

    fp->_w = fp->_lbfsize;

    if (cantwrite (fp))
	return (EOF);

    c = (uchar_t)c;

    /*
     * If it is completely full, flush it out.  Then, in any case,
     * stuff c into the buffer.  If this causes the buffer to fill
     * completely, or if c is '\n' and the file is line buffered,
     * flush it (perhaps a second time).  The second flush will always
     * happen on unbuffered streams, where _bf._size==1; fflush()
     * guarantees that putc() will always call wbuf() by setting _w
     * to 0, so we need not do anything else.
     */

    n = fp->_p - fp->_bf._base;

    if (n >= fp->_bf._size) 
	{
	if (fflush (fp))
	    return (EOF);

	n = 0;
	}

    fp->_w--;
    *fp->_p++ = c;

    if ((++n == fp->_bf._size) || (fp->_flags & __SLBF && c == '\n'))
	if (fflush (fp))
		return (EOF);

    return (c);
    }