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File: [cvs.NetBSD.org] / src / lib / libc / stdio / setvbuf.c (download)

Revision 1.19, Thu Mar 15 18:22:30 2012 UTC (12 years ago) by christos
Branch: MAIN
CVS Tags: yamt-pagecache-base9, yamt-pagecache-base8, yamt-pagecache-base7, yamt-pagecache-base6, yamt-pagecache-base5, yamt-pagecache-base4, tls-maxphys-base, tls-maxphys, tls-earlyentropy-base, tls-earlyentropy, riastradh-xf86-video-intel-2-7-1-pre-2-21-15, riastradh-drm2-base3, riastradh-drm2-base2, riastradh-drm2-base1, riastradh-drm2-base, riastradh-drm2, prg-localcount2-base3, prg-localcount2-base2, prg-localcount2-base1, prg-localcount2-base, prg-localcount2, phil-wifi-base, phil-wifi-20200421, phil-wifi-20200411, phil-wifi-20200406, phil-wifi-20191119, phil-wifi-20190609, phil-wifi, pgoyette-localcount-base, pgoyette-localcount-20170426, pgoyette-localcount-20170320, pgoyette-localcount-20170107, pgoyette-localcount-20161104, pgoyette-localcount-20160806, pgoyette-localcount-20160726, pgoyette-localcount, pgoyette-compat-merge-20190127, pgoyette-compat-base, pgoyette-compat-20190127, pgoyette-compat-20190118, pgoyette-compat-1226, pgoyette-compat-1126, pgoyette-compat-1020, pgoyette-compat-0930, pgoyette-compat-0906, pgoyette-compat-0728, pgoyette-compat-0625, pgoyette-compat-0521, pgoyette-compat-0502, pgoyette-compat-0422, pgoyette-compat-0415, pgoyette-compat-0407, pgoyette-compat-0330, pgoyette-compat-0322, pgoyette-compat-0315, pgoyette-compat, perseant-stdc-iso10646-base, perseant-stdc-iso10646, netbsd-9-base, netbsd-9-3-RELEASE, netbsd-9-2-RELEASE, netbsd-9-1-RELEASE, netbsd-9-0-RELEASE, netbsd-9-0-RC2, netbsd-9-0-RC1, netbsd-9, netbsd-8-base, netbsd-8-2-RELEASE, netbsd-8-1-RELEASE, netbsd-8-1-RC1, netbsd-8-0-RELEASE, netbsd-8-0-RC2, netbsd-8-0-RC1, netbsd-8, netbsd-7-nhusb-base-20170116, netbsd-7-nhusb-base, netbsd-7-nhusb, netbsd-7-base, netbsd-7-2-RELEASE, netbsd-7-1-RELEASE, netbsd-7-1-RC2, netbsd-7-1-RC1, netbsd-7-1-2-RELEASE, netbsd-7-1-1-RELEASE, netbsd-7-1, netbsd-7-0-RELEASE, netbsd-7-0-RC3, netbsd-7-0-RC2, netbsd-7-0-RC1, netbsd-7-0-2-RELEASE, netbsd-7-0-1-RELEASE, netbsd-7-0, netbsd-7, netbsd-10-base, netbsd-10-0-RELEASE, netbsd-10-0-RC6, netbsd-10-0-RC5, netbsd-10-0-RC4, netbsd-10-0-RC3, netbsd-10-0-RC2, netbsd-10-0-RC1, netbsd-10, matt-nb8-mediatek-base, matt-nb8-mediatek, localcount-20160914, is-mlppp-base, is-mlppp, cjep_sun2x-base1, cjep_sun2x-base, cjep_sun2x, cjep_staticlib_x-base1, cjep_staticlib_x-base, cjep_staticlib_x, bouyer-socketcan-base1, bouyer-socketcan-base, bouyer-socketcan, agc-symver-base, agc-symver, HEAD
Changes since 1.18: +6 -10 lines

- ansify, knf.
- no functional changes

/*	$NetBSD: setvbuf.c,v 1.19 2012/03/15 18:22:30 christos 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 <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)setvbuf.c	8.2 (Berkeley) 11/16/93";
#else
__RCSID("$NetBSD: setvbuf.c,v 1.19 2012/03/15 18:22:30 christos Exp $");
#endif
#endif /* LIBC_SCCS and not lint */

#include <assert.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <wchar.h>
#include "reentrant.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;

	_DIAGASSERT(fp != NULL);
	/* buf may be NULL */

	/*
	 * 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 -1;

	FLOCKFILE(fp);
	/*
	 * 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);
	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 = -1;
			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;
	_DIAGASSERT(__type_fit(int, size));
	fp->_bf._size = (int)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 {
			_DIAGASSERT(__type_fit(int, size));
			fp->_w = (int)size;
		}
	} else {
		/* begin/continue reading, or stay in intermediate state */
		fp->_w = 0;
	}
	__cleanup = _cleanup;

	FUNLOCKFILE(fp);
	return ret;
}