StdLib/LibC/Stdio/wbuf.c

   1 /*
   2     Copyright (c) 2010 - 2011, Intel Corporation. All rights reserved.<BR>
   3     This program and the accompanying materials are licensed and made available
   4     under the terms and conditions of the BSD License that accompanies this
   5     distribution.  The full text of the license may be found at
   6     http://opensource.org/licenses/bsd-license.
   7
   8     THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
   9     WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  10
  11  * Copyright (c) 1990, 1993
  12  *  The Regents of the University of California.  All rights reserved.
  13  *
  14  * This code is derived from software contributed to Berkeley by
  15  * Chris Torek.
  16  *
  17  * Redistribution and use in source and binary forms, with or without
  18  * modification, are permitted provided that the following conditions
  19  * are met:
  20  * 1. Redistributions of source code must retain the above copyright
  21  *    notice, this list of conditions and the following disclaimer.
  22  * 2. Redistributions in binary form must reproduce the above copyright
  23  *    notice, this list of conditions and the following disclaimer in the
  24  *    documentation and/or other materials provided with the distribution.
  25  * 3. Neither the name of the University nor the names of its contributors
  26  *    may be used to endorse or promote products derived from this software
  27  *    without specific prior written permission.
  28  *
  29  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  30  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  31  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  32  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  33  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  34  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  35  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  36  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  37  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  38  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  39  * SUCH DAMAGE.
  40
  41     NetBSD: wbuf.c,v 1.13 2003/08/07 16:43:35 agc Exp
  42     wbuf.c  8.1 (Berkeley) 6/4/93
  43 */
  44 #include  <LibConfig.h>
  45 #include <sys/EfiCdefs.h>
  46
  47 #include <assert.h>
  48 #include <errno.h>
  49 #include <stdio.h>
  50 #include "reentrant.h"
  51 #include "local.h"
  52
  53 /*
  54  * Write the given character into the (probably full) buffer for
  55  * the given file.  Flush the buffer out if it is or becomes full,
  56  * or if c=='\n' and the file is line buffered.
  57  */
  58 int
  59 __swbuf(int c, FILE *fp)
  60 {
  61   int n;
  62
  63   //_DIAGASSERT(fp != NULL);
  64   if(fp == NULL) {
  65     errno = EINVAL;
  66     return (EOF);
  67   }
  68
  69   _SET_ORIENTATION(fp, -1);
  70
  71   /*
  72    * In case we cannot write, or longjmp takes us out early,
  73    * make sure _w is 0 (if fully- or un-buffered) or -_bf._size
  74    * (if line buffered) so that we will get called again.
  75    * If we did not do this, a sufficient number of putc()
  76    * calls might wrap _w from negative to positive.
  77    */
  78   fp->_w = fp->_lbfsize;
  79   if (cantwrite(fp)) {
  80     errno = EBADF;
  81     return (EOF);
  82   }
  83   c = (unsigned char)c;
  84
  85   /*
  86    * If it is completely full, flush it out.  Then, in any case,
  87    * stuff c into the buffer.  If this causes the buffer to fill
  88    * completely, or if c is '\n' and the file is line buffered,
  89    * flush it (perhaps a second time).  The second flush will always
  90    * happen on unbuffered streams, where _bf._size==1; fflush()
  91    * guarantees that putc() will always call wbuf() by setting _w
  92    * to 0, so we need not do anything else.
  93    */
  94   n = (int)(fp->_p - fp->_bf._base);
  95   if (n >= fp->_bf._size) {
  96     if (fflush(fp))
  97       return (EOF);
  98     n = 0;
  99   }
 100   fp->_w--;
 101   *fp->_p++ = (unsigned char)c;
 102   if (++n == fp->_bf._size || (fp->_flags & __SLBF && c == '\n'))
 103     if (fflush(fp))
 104       return (EOF);
 105   return (c);
 106 }