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      1 /*	$OpenBSD: stdio.c,v 1.9 2005/08/08 08:05:36 espie Exp $ */
      2 /*-
      3  * Copyright (c) 1990, 1993
      4  *	The Regents of the University of California.  All rights reserved.
      5  *
      6  * This code is derived from software contributed to Berkeley by
      7  * Chris Torek.
      8  *
      9  * Redistribution and use in source and binary forms, with or without
     10  * modification, are permitted provided that the following conditions
     11  * are met:
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  * 2. Redistributions in binary form must reproduce the above copyright
     15  *    notice, this list of conditions and the following disclaimer in the
     16  *    documentation and/or other materials provided with the distribution.
     17  * 3. Neither the name of the University nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  */
     33 
     34 #include <fcntl.h>
     35 #include <unistd.h>
     36 #include <stdio.h>
     37 #include "local.h"
     38 
     39 /*
     40  * Small standard I/O/seek/close functions.
     41  * These maintain the `known seek offset' for seek optimisation.
     42  */
     43 int
     44 __sread(void *cookie, char *buf, int n)
     45 {
     46 	FILE *fp = cookie;
     47 	int ret;
     48 
     49 	ret = read(fp->_file, buf, n);
     50 	/* if the read succeeded, update the current offset */
     51 	if (ret >= 0)
     52 		fp->_offset += ret;
     53 	else
     54 		fp->_flags &= ~__SOFF;	/* paranoia */
     55 	return (ret);
     56 }
     57 
     58 int
     59 __swrite(void *cookie, const char *buf, int n)
     60 {
     61 	FILE *fp = cookie;
     62 
     63 	if (fp->_flags & __SAPP)
     64 		(void) lseek(fp->_file, (off_t)0, SEEK_END);
     65 	fp->_flags &= ~__SOFF;	/* in case FAPPEND mode is set */
     66 	return (write(fp->_file, buf, n));
     67 }
     68 
     69 fpos_t
     70 __sseek(void *cookie, fpos_t offset, int whence)
     71 {
     72 	FILE *fp = cookie;
     73 	off_t ret;
     74 
     75 	ret = lseek(fp->_file, (off_t)offset, whence);
     76 	if (ret == (off_t)-1)
     77 		fp->_flags &= ~__SOFF;
     78 	else {
     79 		fp->_flags |= __SOFF;
     80 		fp->_offset = ret;
     81 	}
     82 	return (ret);
     83 }
     84 
     85 int
     86 __sclose(void *cookie)
     87 {
     88 	return (close(((FILE *)cookie)->_file));
     89 }
     90