vx32

Local 9vx git repository for patches.
git clone git://r-36.net/vx32
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setvbuf.c (4890B)


      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 static char rcsid[] = "$OpenBSD: setvbuf.c,v 1.2 1996/08/19 08:33:05 tholo Exp $";
     39 #endif /* LIBC_SCCS and not lint */
     40 
     41 #include <stdio.h>
     42 #include <stdlib.h>
     43 #include "local.h"
     44 
     45 /*
     46  * Set one of the three kinds of buffering, optionally including
     47  * a buffer.
     48  */
     49 int
     50 setvbuf(fp, buf, mode, size)
     51 	register FILE *fp;
     52 	char *buf;
     53 	register int mode;
     54 	register size_t size;
     55 {
     56 	register int ret, flags;
     57 	size_t iosize;
     58 	int ttyflag;
     59 
     60 	/*
     61 	 * Verify arguments.  The `int' limit on `size' is due to this
     62 	 * particular implementation.  Note, buf and size are ignored
     63 	 * when setting _IONBF.
     64 	 */
     65 	if (mode != _IONBF)
     66 		if ((mode != _IOFBF && mode != _IOLBF) || (int)size < 0)
     67 			return (EOF);
     68 
     69 	/*
     70 	 * Write current buffer, if any.  Discard unread input (including
     71 	 * ungetc data), cancel line buffering, and free old buffer if
     72 	 * malloc()ed.  We also clear any eof condition, as if this were
     73 	 * a seek.
     74 	 */
     75 	ret = 0;
     76 	(void)__sflush(fp);
     77 	if (HASUB(fp))
     78 		FREEUB(fp);
     79 	fp->_r = fp->_lbfsize = 0;
     80 	flags = fp->_flags;
     81 	if (flags & __SMBF)
     82 		free((void *)fp->_bf._base);
     83 	flags &= ~(__SLBF | __SNBF | __SMBF | __SOPT | __SNPT | __SEOF);
     84 
     85 	/* If setting unbuffered mode, skip all the hard work. */
     86 	if (mode == _IONBF)
     87 		goto nbf;
     88 
     89 	/*
     90 	 * Find optimal I/O size for seek optimization.  This also returns
     91 	 * a `tty flag' to suggest that we check isatty(fd), but we do not
     92 	 * care since our caller told us how to buffer.
     93 	 */
     94 	flags |= __swhatbuf(fp, &iosize, &ttyflag);
     95 	if (size == 0) {
     96 		buf = NULL;	/* force local allocation */
     97 		size = iosize;
     98 	}
     99 
    100 	/* Allocate buffer if needed. */
    101 	if (buf == NULL) {
    102 		if ((buf = malloc(size)) == NULL) {
    103 			/*
    104 			 * Unable to honor user's request.  We will return
    105 			 * failure, but try again with file system size.
    106 			 */
    107 			ret = EOF;
    108 			if (size != iosize) {
    109 				size = iosize;
    110 				buf = malloc(size);
    111 			}
    112 		}
    113 		if (buf == NULL) {
    114 			/* No luck; switch to unbuffered I/O. */
    115 nbf:
    116 			fp->_flags = flags | __SNBF;
    117 			fp->_w = 0;
    118 			fp->_bf._base = fp->_p = fp->_nbuf;
    119 			fp->_bf._size = 1;
    120 			return (ret);
    121 		}
    122 		flags |= __SMBF;
    123 	}
    124 
    125 	/*
    126 	 * Kill any seek optimization if the buffer is not the
    127 	 * right size.
    128 	 *
    129 	 * SHOULD WE ALLOW MULTIPLES HERE (i.e., ok iff (size % iosize) == 0)?
    130 	 */
    131 	if (size != iosize)
    132 		flags |= __SNPT;
    133 
    134 	/*
    135 	 * Fix up the FILE fields, and set __cleanup for output flush on
    136 	 * exit (since we are buffered in some way).
    137 	 */
    138 	if (mode == _IOLBF)
    139 		flags |= __SLBF;
    140 	fp->_flags = flags;
    141 	fp->_bf._base = fp->_p = (unsigned char *)buf;
    142 	fp->_bf._size = size;
    143 	/* fp->_lbfsize is still 0 */
    144 	if (flags & __SWR) {
    145 		/*
    146 		 * Begin or continue writing: see __swsetup().  Note
    147 		 * that __SNBF is impossible (it was handled earlier).
    148 		 */
    149 		if (flags & __SLBF) {
    150 			fp->_w = 0;
    151 			fp->_lbfsize = -fp->_bf._size;
    152 		} else
    153 			fp->_w = size;
    154 	} else {
    155 		/* begin/continue reading, or stay in intermediate state */
    156 		fp->_w = 0;
    157 	}
    158 	__cleanup = _cleanup;
    159 
    160 	return (ret);
    161 }