Home | History | Annotate | Line # | Download | only in stdio 
      1 /*	$NetBSD: wsetup.c,v 1.12 2012/03/15 18:22:31 christos Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1990, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This code is derived from software contributed to Berkeley by
      8  * Chris Torek.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. Neither the name of the University nor the names of its contributors
     19  *    may be used to endorse or promote products derived from this software
     20  *    without specific prior written permission.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     32  * SUCH DAMAGE.
     33  */
     34 
     35 #include <sys/cdefs.h>
     36 #if defined(LIBC_SCCS) && !defined(lint)
     37 #if 0
     38 static char sccsid[] = "@(#)wsetup.c	8.1 (Berkeley) 6/4/93";
     39 #else
     40 __RCSID("$NetBSD: wsetup.c,v 1.12 2012/03/15 18:22:31 christos Exp $");
     41 #endif
     42 #endif /* LIBC_SCCS and not lint */
     43 
     44 #include <assert.h>
     45 #include <errno.h>
     46 #include <stdio.h>
     47 #include <stdlib.h>
     48 #include "reentrant.h"
     49 #include "local.h"
     50 
     51 /*
     52  * Various output routines call wsetup to be sure it is safe to write,
     53  * because either _flags does not include __SWR, or _buf is NULL.
     54  * _wsetup returns 0 if OK to write, nonzero otherwise.
     55  */
     56 int
     57 __swsetup(FILE *fp)
     58 {
     59 
     60 	_DIAGASSERT(fp != NULL);
     61 
     62 	/* make sure stdio is set up */
     63 	if (!__sdidinit)
     64 		__sinit();
     65 
     66 	/*
     67 	 * If we are not writing, we had better be reading and writing.
     68 	 */
     69 	if ((fp->_flags & __SWR) == 0) {
     70 		if ((fp->_flags & __SRW) == 0)
     71 			return EOF;
     72 		if (fp->_flags & __SRD) {
     73 			/* clobber any ungetc data */
     74 			if (HASUB(fp))
     75 				FREEUB(fp);
     76 			fp->_flags &= ~(__SRD|__SEOF);
     77 			fp->_r = 0;
     78 			fp->_p = fp->_bf._base;
     79 		}
     80 		fp->_flags |= __SWR;
     81 	}
     82 
     83 	/*
     84 	 * Make a buffer if necessary, then set _w.
     85 	 */
     86 	if (fp->_bf._base == NULL)
     87 		__smakebuf(fp);
     88 	if (fp->_flags & __SLBF) {
     89 		/*
     90 		 * It is line buffered, so make _lbfsize be -_bufsize
     91 		 * for the putc() macro.  We will change _lbfsize back
     92 		 * to 0 whenever we turn off __SWR.
     93 		 */
     94 		fp->_w = 0;
     95 		fp->_lbfsize = -fp->_bf._size;
     96 	} else
     97 		fp->_w = fp->_flags & __SNBF ? 0 : fp->_bf._size;
     98 	return 0;
     99 }
    100