/*	$NetBSD: wsetup.c,v 1.12 2012/03/15 18:22:31 christos Exp $	*/

/*-
 * Copyright (c) 1990, 1993
 *	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. 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 <sys/cdefs.h>
#include <assert.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include "reentrant.h"
#include "local.h"

/*
 * Various output routines call wsetup to be sure it is safe to write,
 * because either _flags does not include __SWR, or _buf is NULL.
 * _wsetup returns 0 if OK to write, nonzero otherwise.
 */
int __swsetup(FILE *fp) {

  _DIAGASSERT(fp != NULL);

  /* make sure stdio is set up */
  if (!__sdidinit)
    __sinit();

  /*
   * If we are not writing, we had better be reading and writing.
   */
  if ((fp->_flags & __SWR) == 0) {
    if ((fp->_flags & __SRW) == 0)
      return EOF;
    if (fp->_flags & __SRD) {
      /* clobber any ungetc data */
      if (HASUB(fp))
        FREEUB(fp);
      fp->_flags &= ~(__SRD | __SEOF);
      fp->_r = 0;
      fp->_p = fp->_bf._base;
    }
    fp->_flags |= __SWR;
  }

  /*
   * Make a buffer if necessary, then set _w.
   */
  if (fp->_bf._base == NULL)
    __smakebuf(fp);
  if (fp->_flags & __SLBF) {
    /*
     * It is line buffered, so make _lbfsize be -_bufsize
     * for the putc() macro.  We will change _lbfsize back
     * to 0 whenever we turn off __SWR.
     */
    fp->_w = 0;
    fp->_lbfsize = -fp->_bf._size;
  } else
    fp->_w = fp->_flags & __SNBF ? 0 : fp->_bf._size;
  return 0;
}
