stdio/wsetup.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26  * Copyright (c) 1990, 1993
  27  *      The Regents of the University of California.  All rights reserved.
  28  *
  29  * This code is derived from software contributed to Berkeley by
  30  * Chris Torek.
  31  *
  32  * Redistribution and use in source and binary forms, with or without
  33  * modification, are permitted provided that the following conditions
  34  * are met:
  35  * 1. Redistributions of source code must retain the above copyright
  36  *    notice, this list of conditions and the following disclaimer.
  37  * 2. Redistributions in binary form must reproduce the above copyright
  38  *    notice, this list of conditions and the following disclaimer in the
  39  *    documentation and/or other materials provided with the distribution.
  40  * 3. All advertising materials mentioning features or use of this software
  41  *    must display the following acknowledgement:
  42  *      This product includes software developed by the University of
  43  *      California, Berkeley and its contributors.
  44  * 4. Neither the name of the University nor the names of its contributors
  45  *    may be used to endorse or promote products derived from this software
  46  *    without specific prior written permission.
  47  *
  48  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  58  * SUCH DAMAGE.
  59  */
  60
  61
  62 #include <stdio.h>
  63 #include <stdlib.h>
  64 #include "local.h"
  65
  66 /*
  67  * Various output routines call wsetup to be sure it is safe to write,
  68  * because either _flags does not include __SWR, or _buf is NULL.
  69  * _wsetup returns 0 if OK to write, nonzero otherwise.
  70  */
  71 int
  72 __swsetup(fp)
  73         register FILE *fp;
  74 {
  75         /* make sure stdio is set up */
  76         if (!__sdidinit)
  77                 __sinit();
  78
  79         /*
  80          * If we are not writing, we had better be reading and writing.
  81          */
  82         if ((fp->_flags & __SWR) == 0) {
  83                 if ((fp->_flags & __SRW) == 0)
  84                         return (EOF);
  85                 if (fp->_flags & __SRD) {
  86                         /* clobber any ungetc data */
  87                         if (HASUB(fp))
  88                                 FREEUB(fp);
  89                         fp->_flags &= ~(__SRD|__SEOF);
  90                         fp->_r = 0;
  91                         fp->_p = fp->_bf._base;
  92                 }
  93                 fp->_flags |= __SWR;
  94         }
  95
  96         /*
  97          * Make a buffer if necessary, then set _w.
  98          */
  99         if (fp->_bf._base == NULL)
 100                 __smakebuf(fp);
 101         if (fp->_flags & __SLBF) {
 102                 /*
 103                  * It is line buffered, so make _lbfsize be -_bufsize
 104                  * for the putc() macro.  We will change _lbfsize back
 105                  * to 0 whenever we turn off __SWR.
 106                  */
 107                 fp->_w = 0;
 108                 fp->_lbfsize = -fp->_bf._size;
 109         } else
 110                 fp->_w = fp->_flags & __SNBF ? 0 : fp->_bf._size;
 111         return (0);
 112 }