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/* $OpenBSD: setvbuf.c,v 1.11 2009/11/09 00:18:27 kurt Exp $ */
/*-
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Chris Torek.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <stdio.h>
#include <stdlib.h>
#include "local.h"
/*
* Set one of the three kinds of buffering, optionally including
* a buffer.
*/
int
setvbuf(FILE *fp, char *buf, int mode, size_t size)
{
int ret, flags;
size_t iosize;
int ttyflag;
/*
* Verify arguments. The `int' limit on `size' is due to this
* particular implementation. Note, buf and size are ignored
* when setting _IONBF.
*/
if (mode != _IONBF)
if ((mode != _IOFBF && mode != _IOLBF) || (int)size < 0)
return (EOF);
/*
* Write current buffer, if any. Discard unread input (including
* ungetc data), cancel line buffering, and free old buffer if
* malloc()ed. We also clear any eof condition, as if this were
* a seek.
*/
FLOCKFILE(fp);
ret = 0;
(void)__sflush(fp);
if (HASUB(fp))
FREEUB(fp);
WCIO_FREE(fp);
fp->_r = fp->_lbfsize = 0;
flags = fp->_flags;
if (flags & __SMBF)
free((void *)fp->_bf._base);
flags &= ~(__SLBF | __SNBF | __SMBF | __SOPT | __SNPT | __SEOF);
/* If setting unbuffered mode, skip all the hard work. */
if (mode == _IONBF)
goto nbf;
/*
* Find optimal I/O size for seek optimization. This also returns
* a `tty flag' to suggest that we check isatty(fd), but we do not
* care since our caller told us how to buffer.
*/
flags |= __swhatbuf(fp, &iosize, &ttyflag);
if (size == 0) {
buf = NULL; /* force local allocation */
size = iosize;
}
/* Allocate buffer if needed. */
if (buf == NULL) {
if ((buf = malloc(size)) == NULL) {
/*
* Unable to honor user's request. We will return
* failure, but try again with file system size.
*/
ret = EOF;
if (size != iosize) {
size = iosize;
buf = malloc(size);
}
}
if (buf == NULL) {
/* No luck; switch to unbuffered I/O. */
nbf:
fp->_flags = flags | __SNBF;
fp->_w = 0;
fp->_bf._base = fp->_p = fp->_nbuf;
fp->_bf._size = 1;
FUNLOCKFILE(fp);
return (ret);
}
flags |= __SMBF;
}
/*
* Kill any seek optimization if the buffer is not the
* right size.
*
* SHOULD WE ALLOW MULTIPLES HERE (i.e., ok iff (size % iosize) == 0)?
*/
if (size != iosize)
flags |= __SNPT;
/*
* Fix up the FILE fields, and set __cleanup for output flush on
* exit (since we are buffered in some way).
*/
if (mode == _IOLBF)
flags |= __SLBF;
fp->_flags = flags;
fp->_bf._base = fp->_p = (unsigned char *)buf;
fp->_bf._size = size;
/* fp->_lbfsize is still 0 */
if (flags & __SWR) {
/*
* Begin or continue writing: see __swsetup(). Note
* that __SNBF is impossible (it was handled earlier).
*/
if (flags & __SLBF) {
fp->_w = 0;
fp->_lbfsize = -fp->_bf._size;
} else
fp->_w = size;
} else {
/* begin/continue reading, or stay in intermediate state */
fp->_w = 0;
}
FUNLOCKFILE(fp);
__atexit_register_cleanup(_cleanup);
return (ret);
}
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