stdio.subproj/wsetup.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Copyright (c) 1990, 1993
  24  *      The Regents of the University of California.  All rights reserved.
  25  *
  26  * This code is derived from software contributed to Berkeley by
  27  * Chris Torek.
  28  *
  29  * Redistribution and use in source and binary forms, with or without
  30  * modification, are permitted provided that the following conditions
  31  * are met:
  32  * 1. Redistributions of source code must retain the above copyright
  33  *    notice, this list of conditions and the following disclaimer.
  34  * 2. Redistributions in binary form must reproduce the above copyright
  35  *    notice, this list of conditions and the following disclaimer in the
  36  *    documentation and/or other materials provided with the distribution.
  37  * 3. All advertising materials mentioning features or use of this software
  38  *    must display the following acknowledgement:
  39  *      This product includes software developed by the University of
  40  *      California, Berkeley and its contributors.
  41  * 4. Neither the name of the University nor the names of its contributors
  42  *    may be used to endorse or promote products derived from this software
  43  *    without specific prior written permission.
  44  *
  45  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  46  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  47  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  48  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  49  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  50  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  51  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  52  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  53  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  54  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  55  * SUCH DAMAGE.
  56  */
  57
  58
  59 #include <stdio.h>
  60 #include <stdlib.h>
  61 #include "local.h"
  62
  63 /*
  64  * Various output routines call wsetup to be sure it is safe to write,
  65  * because either _flags does not include __SWR, or _buf is NULL.
  66  * _wsetup returns 0 if OK to write, nonzero otherwise.
  67  */
  68 int
  69 __swsetup(fp)
  70         register FILE *fp;
  71 {
  72         /* make sure stdio is set up */
  73         if (!__sdidinit)
  74                 __sinit();
  75
  76         /*
  77          * If we are not writing, we had better be reading and writing.
  78          */
  79         if ((fp->_flags & __SWR) == 0) {
  80                 if ((fp->_flags & __SRW) == 0)
  81                         return (EOF);
  82                 if (fp->_flags & __SRD) {
  83                         /* clobber any ungetc data */
  84                         if (HASUB(fp))
  85                                 FREEUB(fp);
  86                         fp->_flags &= ~(__SRD|__SEOF);
  87                         fp->_r = 0;
  88                         fp->_p = fp->_bf._base;
  89                 }
  90                 fp->_flags |= __SWR;
  91         }
  92
  93         /*
  94          * Make a buffer if necessary, then set _w.
  95          */
  96         if (fp->_bf._base == NULL)
  97                 __smakebuf(fp);
  98         if (fp->_flags & __SLBF) {
  99                 /*
 100                  * It is line buffered, so make _lbfsize be -_bufsize
 101                  * for the putc() macro.  We will change _lbfsize back
 102                  * to 0 whenever we turn off __SWR.
 103                  */
 104                 fp->_w = 0;
 105                 fp->_lbfsize = -fp->_bf._size;
 106         } else
 107                 fp->_w = fp->_flags & __SNBF ? 0 : fp->_bf._size;
 108         return (0);
 109 }