/*- * 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. All advertising materials mentioning features or use of this software *    must display the following acknowledgement: *	This product includes software developed by the University of *	California, Berkeley and its contributors. * 4. 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. */ #if defined(LIBC_SCCS) && !defined(lint)static char rcsid[] = "$OpenBSD: setvbuf.c,v 1.2 1996/08/19 08:33:05 tholo Exp $";#endif /* LIBC_SCCS and not lint */ #include <stdio.h>#include <stdlib.h>#include "local.h" /* * Set one of the three kinds of buffering, optionally including * a buffer. */intsetvbuf(fp, buf, mode, size)	register FILE *fp;	char *buf;	register int mode;	register size_t size;{	register 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.	 */	ret = 0;	(void)__sflush(fp);	if (HASUB(fp))		FREEUB(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;			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;	}	__cleanup = _cleanup; 	return (ret);}