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stdio.c revision 1.1.1.2 
      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 sccsid[] = "@(#)stdio.c	8.1 (Berkeley) 6/4/93";
     39 #endif /* LIBC_SCCS and not lint */
     40 
     41 #include <fcntl.h>
     42 #include <unistd.h>
     43 #include <stdio.h>
     44 #include "local.h"
     45 
     46 /*
     47  * Small standard I/O/seek/close functions.
     48  * These maintain the `known seek offset' for seek optimisation.
     49  */
     50 __sread(cookie, buf, n)
     51 	void *cookie;
     52 	char *buf;
     53 	int n;
     54 {
     55 	register FILE *fp = cookie;
     56 	register int ret;
     57 
     58 	ret = read(fp->_file, buf, n);
     59 	/* if the read succeeded, update the current offset */
     60 	if (ret >= 0)
     61 		fp->_offset += ret;
     62 	else
     63 		fp->_flags &= ~__SOFF;	/* paranoia */
     64 	return (ret);
     65 }
     66 
     67 __swrite(cookie, buf, n)
     68 	void *cookie;
     69 	char const *buf;
     70 	int n;
     71 {
     72 	register FILE *fp = cookie;
     73 
     74 	if (fp->_flags & __SAPP)
     75 		(void) lseek(fp->_file, (off_t)0, SEEK_END);
     76 	fp->_flags &= ~__SOFF;	/* in case FAPPEND mode is set */
     77 	return (write(fp->_file, buf, n));
     78 }
     79 
     80 fpos_t
     81 __sseek(cookie, offset, whence)
     82 	void *cookie;
     83 	fpos_t offset;
     84 	int whence;
     85 {
     86 	register FILE *fp = cookie;
     87 	register off_t ret;
     88 
     89 	ret = lseek(fp->_file, (off_t)offset, whence);
     90 	if (ret == -1L)
     91 		fp->_flags &= ~__SOFF;
     92 	else {
     93 		fp->_flags |= __SOFF;
     94 		fp->_offset = ret;
     95 	}
     96 	return (ret);
     97 }
     98 
     99 __sclose(cookie)
    100 	void *cookie;
    101 {
    102 
    103 	return (close(((FILE *)cookie)->_file));
    104 }
    105