newlib/libc/stdio/wsetup.c

   1 /* No user fns here. Pesch 15apr92. */
   2
   3 /*
   4  * Copyright (c) 1990, 2007 The Regents of the University of California.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms are permitted
   8  * provided that the above copyright notice and this paragraph are
   9  * duplicated in all such forms and that any documentation,
  10  * and/or other materials related to such
  11  * distribution and use acknowledge that the software was developed
  12  * by the University of California, Berkeley.  The name of the
  13  * University may not be used to endorse or promote products derived
  14  * from this software without specific prior written permission.
  15  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  17  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  18  */
  19
  20 #include <_ansi.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <errno.h>
  24 #include "local.h"
  25
  26 /*
  27  * Various output routines call wsetup to be sure it is safe to write,
  28  * because either _flags does not include __SWR, or _buf is NULL.
  29  * _wsetup returns 0 if OK to write, nonzero and set errno otherwise.
  30  */
  31
  32 int
  33 __swsetup_r (struct _reent *ptr,
  34        register FILE * fp)
  35 {
  36   /* Make sure stdio is set up.  */
  37
  38   CHECK_INIT (_REENT, fp);
  39
  40   /*
  41    * If we are not writing, we had better be reading and writing.
  42    */
  43
  44   if ((fp->_flags & __SWR) == 0)
  45     {
  46       if ((fp->_flags & __SRW) == 0)
  47         {
  48           _REENT_ERRNO(ptr) = EBADF;
  49           fp->_flags |= __SERR;
  50           return EOF;
  51         }
  52       if (fp->_flags & __SRD)
  53         {
  54           /* clobber any ungetc data */
  55           if (HASUB (fp))
  56             FREEUB (ptr, fp);
  57           fp->_flags &= ~(__SRD | __SEOF);
  58           fp->_r = 0;
  59           fp->_p = fp->_bf._base;
  60         }
  61       fp->_flags |= __SWR;
  62     }
  63
  64   /*
  65    * Make a buffer if necessary, then set _w.
  66    * A string I/O file should not explicitly allocate a buffer
  67    * unless asprintf is being used.
  68    */
  69   if (fp->_bf._base == NULL
  70         && (!(fp->_flags & __SSTR) || (fp->_flags & __SMBF)))
  71     __smakebuf_r (ptr, fp);
  72
  73   if (fp->_flags & __SLBF)
  74     {
  75       /*
  76        * It is line buffered, so make _lbfsize be -_bufsize
  77        * for the putc() macro.  We will change _lbfsize back
  78        * to 0 whenever we turn off __SWR.
  79        */
  80       fp->_w = 0;
  81       fp->_lbfsize = -fp->_bf._size;
  82     }
  83   else
  84     fp->_w = fp->_flags & __SNBF ? 0 : fp->_bf._size;
  85
  86   if (!fp->_bf._base && (fp->_flags & __SMBF))
  87     {
  88       /* __smakebuf_r set errno, but not flag */
  89       fp->_flags |= __SERR;
  90       return EOF;
  91     }
  92   return 0;
  93 }