[apple/libc.git] / stdio / FreeBSD / makebuf.c

/*-
 * 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.
 * 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 sccsid[] = "@(#)makebuf.c	8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/lib/libc/stdio/makebuf.c,v 1.6 2007/01/09 00:28:07 imp Exp $");

#include "namespace.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include "un-namespace.h"

#include "libc_private.h"
#include "local.h"

#ifdef FEATURE_SMALL_STDIOBUF
# define MAXBUFSIZE	(1 << 12)
#else
# define MAXBUFSIZE	(1 << 16)
#endif

#define TTYBUFSIZE	4096

/*
 * Allocate a file buffer, or switch to unbuffered I/O.
 * Per the ANSI C standard, ALL tty devices default to line buffered.
 *
 * As a side effect, we set __SOPT or __SNPT (en/dis-able fseek
 * optimisation) right after the _fstat() that finds the buffer size.
 */
void
__smakebuf(fp)
	FILE *fp;
{
	void *p;
	int flags;
	size_t size;
	int couldbetty;

	if (fp->_flags & __SNBF) {
		fp->_bf._base = fp->_p = fp->_nbuf;
		fp->_bf._size = 1;
		return;
	}
	flags = __swhatbuf(fp, &size, &couldbetty);
	if (couldbetty && isatty(fp->_file)) {
		flags |= __SLBF;
		/* st_blksize for ttys is 128K, so make it more reasonable */
		if (size > TTYBUFSIZE)
			fp->_blksize = size = TTYBUFSIZE;
	}
	if ((p = malloc(size)) == NULL) {
		fp->_flags |= __SNBF;
		fp->_bf._base = fp->_p = fp->_nbuf;
		fp->_bf._size = 1;
		return;
	}
	__cleanup = _cleanup;
	flags |= __SMBF;
	fp->_bf._base = fp->_p = p;
	fp->_bf._size = size;
	fp->_flags |= flags;
}

/*
 * Internal routine to determine `proper' buffering for a file.
 */
int
__swhatbuf(fp, bufsize, couldbetty)
	FILE *fp;
	size_t *bufsize;
	int *couldbetty;
{
	struct stat st;

	if (fp->_file < 0 || _fstat(fp->_file, &st) < 0) {
		*couldbetty = 0;
		*bufsize = BUFSIZ;
		return (__SNPT);
	}

	/* could be a tty iff it is a character device */
	*couldbetty = (st.st_mode & S_IFMT) == S_IFCHR;
	if (st.st_blksize <= 0) {
		*bufsize = BUFSIZ;
		return (__SNPT);
	}

	/*
	 * Optimise fseek() only if it is a regular file.  (The test for
	 * __sseek is mainly paranoia.)  It is safe to set _blksize
	 * unconditionally; it will only be used if __SOPT is also set.
	 */
	fp->_blksize = *bufsize = st.st_blksize > MAXBUFSIZE ? MAXBUFSIZE : st.st_blksize;
	return ((st.st_mode & S_IFMT) == S_IFREG && fp->_seek == __sseek ?
	    __SOPT : __SNPT);
}
Commit	Line	Data
9385eb3d	1	/*-
e9ce8d39 A	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.
e9ce8d39 A	16	* 4. Neither the name of the University nor the names of its contributors
	17	* may be used to endorse or promote products derived from this software
	18	* without specific prior written permission.
	19	*
	20	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	21	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	22	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	23	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	24	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	25	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	26	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	27	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	28	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	29	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	30	* SUCH DAMAGE.
	31	*/
	32
9385eb3d A	33	#if defined(LIBC_SCCS) && !defined(lint)
	34	static char sccsid[] = "@(#)makebuf.c 8.1 (Berkeley) 6/4/93";
	35	#endif /* LIBC_SCCS and not lint */
	36	#include <sys/cdefs.h>
1f2f436a	37	__FBSDID("$FreeBSD: src/lib/libc/stdio/makebuf.c,v 1.6 2007/01/09 00:28:07 imp Exp $");
e9ce8d39	38
9385eb3d	39	#include "namespace.h"
e9ce8d39 A	40	#include <sys/types.h>
	41	#include <sys/stat.h>
	42	#include <unistd.h>
	43	#include <stdio.h>
	44	#include <stdlib.h>
9385eb3d	45	#include "un-namespace.h"
e9ce8d39	46
1f2f436a A	47	#include "libc_private.h"
	48	#include "local.h"
	49
6465356a A	50	#ifdef FEATURE_SMALL_STDIOBUF
	51	# define MAXBUFSIZE (1 << 12)
	52	#else
	53	# define MAXBUFSIZE (1 << 16)
	54	#endif
	55
ad3c9f2a A	56	#define TTYBUFSIZE 4096
ad3c9f2a A	57
e9ce8d39 A	58	/*
	59	* Allocate a file buffer, or switch to unbuffered I/O.
	60	* Per the ANSI C standard, ALL tty devices default to line buffered.
	61	*
	62	* As a side effect, we set __SOPT or __SNPT (en/dis-able fseek
9385eb3d	63	* optimisation) right after the _fstat() that finds the buffer size.
e9ce8d39 A	64	*/
	65	void
	66	__smakebuf(fp)
9385eb3d	67	FILE *fp;
e9ce8d39	68	{
9385eb3d A	69	void *p;
9385eb3d A	70	int flags;
e9ce8d39 A	71	size_t size;
	72	int couldbetty;
	73
	74	if (fp->_flags & __SNBF) {
	75	fp->_bf._base = fp->_p = fp->_nbuf;
	76	fp->_bf._size = 1;
	77	return;
	78	}
	79	flags = __swhatbuf(fp, &size, &couldbetty);
ad3c9f2a A	80	if (couldbetty && isatty(fp->_file)) {
	81	flags \|= __SLBF;
	82	/* st_blksize for ttys is 128K, so make it more reasonable */
	83	if (size > TTYBUFSIZE)
	84	fp->_blksize = size = TTYBUFSIZE;
	85	}
e9ce8d39 A	86	if ((p = malloc(size)) == NULL) {
	87	fp->_flags \|= __SNBF;
	88	fp->_bf._base = fp->_p = fp->_nbuf;
	89	fp->_bf._size = 1;
	90	return;
	91	}
	92	__cleanup = _cleanup;
	93	flags \|= __SMBF;
	94	fp->_bf._base = fp->_p = p;
	95	fp->_bf._size = size;
e9ce8d39 A	96	fp->_flags \|= flags;
	97	}
	98
	99	/*
	100	* Internal routine to determine `proper' buffering for a file.
	101	*/
	102	int
	103	__swhatbuf(fp, bufsize, couldbetty)
9385eb3d	104	FILE *fp;
e9ce8d39 A	105	size_t *bufsize;
	106	int *couldbetty;
	107	{
	108	struct stat st;
	109
9385eb3d	110	if (fp->_file < 0 \|\| _fstat(fp->_file, &st) < 0) {
e9ce8d39 A	111	*couldbetty = 0;
	112	*bufsize = BUFSIZ;
	113	return (__SNPT);
	114	}
	115
	116	/* could be a tty iff it is a character device */
	117	*couldbetty = (st.st_mode & S_IFMT) == S_IFCHR;
	118	if (st.st_blksize <= 0) {
	119	*bufsize = BUFSIZ;
	120	return (__SNPT);
	121	}
	122
	123	/*
	124	* Optimise fseek() only if it is a regular file. (The test for
	125	* __sseek is mainly paranoia.) It is safe to set _blksize
	126	* unconditionally; it will only be used if __SOPT is also set.
	127	*/
ad3c9f2a	128	fp->_blksize = *bufsize = st.st_blksize > MAXBUFSIZE ? MAXBUFSIZE : st.st_blksize;
e9ce8d39 A	129	return ((st.st_mode & S_IFMT) == S_IFREG && fp->_seek == __sseek ?
	130	__SOPT : __SNPT);
	131	}