WebSVN - shark - Blame - Rev 39 - /shark/branches/pj/libc/stdio/setvbuf.c

Rev	Author	Line No.	Line
2	pj	1	/*-
		2	* Copyright (c) 1990, 1993
		3	* The Regents of the University of California. All rights reserved.
		4	*
		5	* This code is derived from software contributed to Berkeley by
		6	* Chris Torek.
		7	*
		8	* Redistribution and use in source and binary forms, with or without
		9	* modification, are permitted provided that the following conditions
		10	* are met:
		11	* 1. Redistributions of source code must retain the above copyright
		12	* notice, this list of conditions and the following disclaimer.
		13	* 2. Redistributions in binary form must reproduce the above copyright
		14	* notice, this list of conditions and the following disclaimer in the
		15	* documentation and/or other materials provided with the distribution.
		16	* 3. All advertising materials mentioning features or use of this software
		17	* must display the following acknowledgement:
		18	* This product includes software developed by the University of
		19	* California, Berkeley and its contributors.
		20	* 4. Neither the name of the University nor the names of its contributors
		21	* may be used to endorse or promote products derived from this software
		22	* without specific prior written permission.
		23	*
		24	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
		25	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
		26	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
		27	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
		28	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
		29	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
		30	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
		31	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
		32	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
		33	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
		34	* SUCH DAMAGE.
		35	*/
		36
		37	#if defined(LIBC_SCCS) && !defined(lint)
		38	#if 0
		39	static char sccsid[] = "@(#)setvbuf.c 8.2 (Berkeley) 11/16/93";
		40	#endif
		41	static const char rcsid[] =
		42	"$\Id: setvbuf.c,v 1.3 1996/06/22 10:33:53 jraynard Exp $";
		43	#endif /* LIBC_SCCS and not lint */
		44
		45	#include <stdio.h>
		46	#include <stdlib.h>
		47	#include "local.h"
		48	#ifdef _THREAD_SAFE
		49	#include <pthread.h>
		50	#include "pthread_private.h"
		51	#endif
		52
		53	/*
		54	* Set one of the three kinds of buffering, optionally including
		55	* a buffer.
		56	*/
		57	int
		58	setvbuf(fp, buf, mode, size)
		59	register FILE *fp;
		60	char *buf;
		61	register int mode;
		62	register size_t size;
		63	{
		64	register int ret, flags;
		65	size_t iosize;
		66	int ttyflag;
		67
		68	/*
		69	* Verify arguments. The `int' limit on `size' is due to this
		70	* particular implementation. Note, buf and size are ignored
		71	* when setting _IONBF.
		72	*/
		73	if (mode != _IONBF)
		74	if ((mode != _IOFBF && mode != _IOLBF) \|\| (int)size < 0)
		75	return (EOF);
		76
		77	#ifdef _THREAD_SAFE
		78	_thread_flockfile(fp,__FILE__,__LINE__);
		79	#endif
		80	/*
		81	* Write current buffer, if any. Discard unread input (including
		82	* ungetc data), cancel line buffering, and free old buffer if
		83	* malloc()ed. We also clear any eof condition, as if this were
		84	* a seek.
		85	*/
		86	ret = 0;
		87	(void)__sflush(fp);
		88	if (HASUB(fp))
		89	FREEUB(fp);
		90	fp->_r = fp->_lbfsize = 0;
		91	flags = fp->_flags;
		92	if (flags & __SMBF)
		93	free((void *)fp->_bf._base);
		94	flags &= ~(__SLBF \| __SNBF \| __SMBF \| __SOPT \| __SNPT \| __SEOF);
		95
		96	/* If setting unbuffered mode, skip all the hard work. */
		97	if (mode == _IONBF)
		98	goto nbf;
		99
		100	/*
		101	* Find optimal I/O size for seek optimization. This also returns
		102	* a `tty flag' to suggest that we check isatty(fd), but we do not
		103	* care since our caller told us how to buffer.
		104	*/
		105	flags \|= __swhatbuf(fp, &iosize, &ttyflag);
		106	if (size == 0) {
		107	buf = NULL; /* force local allocation */
		108	size = iosize;
		109	}
		110
		111	/* Allocate buffer if needed. */
		112	if (buf == NULL) {
		113	if ((buf = malloc(size)) == NULL) {
		114	/*
		115	* Unable to honor user's request. We will return
		116	* failure, but try again with file system size.
		117	*/
		118	ret = EOF;
		119	if (size != iosize) {
		120	size = iosize;
		121	buf = malloc(size);
		122	}
		123	}
		124	if (buf == NULL) {
		125	/* No luck; switch to unbuffered I/O. */
		126	nbf:
		127	fp->_flags = flags \| __SNBF;
		128	fp->_w = 0;
		129	fp->_bf._base = fp->_p = fp->_nbuf;
		130	fp->_bf._size = 1;
		131	#ifdef _THREAD_SAFE
		132	_thread_funlockfile(fp);
		133	#endif
		134	return (ret);
		135	}
		136	flags \|= __SMBF;
		137	}
		138
		139	/*
		140	* Kill any seek optimization if the buffer is not the
		141	* right size.
		142	*
		143	* SHOULD WE ALLOW MULTIPLES HERE (i.e., ok iff (size % iosize) == 0)?
		144	*/
		145	if (size != iosize)
		146	flags \|= __SNPT;
		147
		148	/*
		149	* Fix up the FILE fields, and set __cleanup for output flush on
		150	* exit (since we are buffered in some way).
		151	*/
		152	if (mode == _IOLBF)
		153	flags \|= __SLBF;
		154	fp->_flags = flags;
		155	fp->_bf._base = fp->_p = (unsigned char *)buf;
		156	fp->_bf._size = size;
		157	/* fp->_lbfsize is still 0 */
		158	if (flags & __SWR) {
		159	/*
		160	* Begin or continue writing: see __swsetup(). Note
		161	* that __SNBF is impossible (it was handled earlier).
		162	*/
		163	if (flags & __SLBF) {
		164	fp->_w = 0;
		165	fp->_lbfsize = -fp->_bf._size;
		166	} else
		167	fp->_w = size;
		168	} else {
		169	/* begin/continue reading, or stay in intermediate state */
		170	fp->_w = 0;
		171	}
		172	__cleanup = _cleanup;
		173
		174	#ifdef _THREAD_SAFE
		175	_thread_funlockfile(fp);
		176	#endif
		177	return (ret);
		178	}

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