File: [local] / prex-old / usr / lib / libc / stdio / makebuf.c (download)
Revision 1.1.1.1 (vendor branch), Tue Jun 3 09:38:48 2008 UTC (16 years, 3 months ago) by nbrk
Branch: MAIN, KOHSUKE
CVS Tags: PREX_0_8_BASE, PREX_0_7_BASE, HEAD Changes since 1.1: +0 -0 lines
Yeah, this is an initial import of Prex, portable real-time microkernel
operating system. I wanna hack it for non-profit but fun, so let it in.
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/*-
* 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/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include "local.h"
/*
* Internal routine to determine `proper' buffering for a file.
*/
static int
__swhatbuf(FILE *fp, size_t *bufsize, int *couldbetty)
{
struct stat st;
*bufsize = BUFSIZ;
*couldbetty = 0;
if (fp->_file < 0 || fstat(fp->_file, &st) < 0)
return 0;
/* could be a tty iff it is a character device */
*couldbetty = S_ISCHR(st.st_mode);
return 0;
}
/*
* 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 ((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;
if (couldbetty && isatty(fp->_file))
flags |= __SLBF;
fp->_flags |= flags;
}