os/ossrv/genericopenlibs/cstdlib/LSTDIO/WBUF.C
author sl
Tue, 10 Jun 2014 14:32:02 +0200
changeset 1 260cb5ec6c19
permissions -rw-r--r--
Update contrib.
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/* WBUF.C
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 * 
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 * Portions Copyright (c) 1990-1999 Nokia Corporation and/or its subsidiary(-ies).
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 * All rights reserved.
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 */
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/* No user fns here.  Pesch 15apr92. */
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/*
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 * Copyright (c) 1990 The Regents of the University of California.
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms are permitted
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 * provided that the above copyright notice and this paragraph are
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 * duplicated in all such forms and that any documentation,
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 * advertising materials, and other materials related to such
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 * distribution and use acknowledge that the software was developed
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 * by the University of California, Berkeley.  The name of the
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 * University may not be used to endorse or promote products derived
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 * from this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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 */
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#include <stdio.h>
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#include "LOCAL.H"
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#include "FVWRITE.H"
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/*
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 * Write the given character into the (probably full) buffer for
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 * the given file.  Flush the buffer out if it is or becomes full,
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 * or if c=='\n' and the file is line buffered.
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 */
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int
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__swbuf (register int c,register FILE *fp)
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{
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  register int n;
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  /* Ensure stdio has been initialized.  */
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  CHECK_INIT (fp);
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  /*
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   * In case we cannot write, or longjmp takes us out early,
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   * make sure _w is 0 (if fully- or un-buffered) or -_bf._size
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   * (if line buffered) so that we will get called again.
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   * If we did not do this, a sufficient number of putc()
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   * calls might wrap _w from negative to positive.
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   */
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  fp->_w = fp->_lbfsize;
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  if (cantwrite (fp))
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    return EOF;
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  c = (unsigned char) c;
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  /*
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   * If it is completely full, flush it out.  Then, in any case,
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   * stuff c into the buffer.  If this causes the buffer to fill
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   * completely, or if c is '\n' and the file is line buffered,
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   * flush it (perhaps a second time).  The second flush will always
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   * happen on unbuffered streams, where _bf._size==1; fflush()
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   * guarantees that putc() will always call wbuf() by setting _w
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   * to 0, so we need not do anything else.
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   */
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  n = fp->_p - fp->_bf._base;
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  if (n >= fp->_bf._size)
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    {
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      if (fflush (fp))
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	return EOF;
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      n = 0;
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    }
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  fp->_w--;
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  *fp->_p++ = (unsigned char)c;
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  if (++n == fp->_bf._size || (fp->_flags & __SLBF && c == '\n'))
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    if (fflush (fp))
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      return EOF;
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  return c;
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}