xref: /titanic_41/usr/src/lib/libbc/libc/stdio/common/fwrite.c (revision 7c478bd95313f5f23a4c958a745db2134aa03244)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 1989 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*      Copyright (c) 1984 AT&T */
28 /*        All Rights Reserved   */
29 
30 #pragma ident	"%Z%%M%	%I%	%E% SMI"  /* from S5R2 3.6 */
31 
32 /*LINTLIBRARY*/
33 /*
34  * This version writes directly to the buffer rather than looping on putc.
35  * Ptr args aren't checked for NULL because the program would be a
36  * catastrophic mess anyway.  Better to abort than just to return NULL.
37  *
38  * This version does buffered writes larger than BUFSIZ directly, when
39  * the buffer is empty.
40  */
41 #include <stdio.h>
42 #include "stdiom.h"
43 
44 #define MIN(x, y)       (x < y ? x : y)
45 
46 extern char *memcpy();
47 
48 int
fwrite(ptr,size,count,iop)49 fwrite(ptr, size, count, iop)
50 char *ptr;
51 int size, count;
52 register FILE *iop;
53 {
54 	register unsigned nleft;
55 	register int n;
56 	register unsigned char *cptr, *bufend;
57 	register unsigned char *prev_ptr;
58 
59 	if (size <= 0 || count <= 0 || _WRTCHK(iop))
60 	        return (0);
61 
62 	bufend = iop->_base + iop->_bufsiz;
63 	nleft = count*size;
64 
65 	/* if the file is unbuffered, or if the iop->ptr = iop->base, and there
66 	   is > BUFSZ chars to write, we can do a direct write */
67 	prev_ptr = iop->_ptr;
68 	if (iop->_base >= iop->_ptr)  {	/*this covers the unbuffered case, too*/
69 		if (((iop->_flag & _IONBF) != 0) || (nleft >= BUFSIZ))  {
70 			if ((n=write(fileno(iop),ptr,nleft)) != nleft)
71 			    {
72 				iop->_flag |= _IOERR;
73 				n = (n >= 0) ? n : 0;
74 			}
75 			return n/size;
76 		}
77 	}
78 	/* Put characters in the buffer */
79 	/* note that the meaning of n when just starting this loop is
80 	   irrelevant.  It is defined in the loop */
81 	for (; ; ptr += n) {
82 	        while ((n = bufend - (cptr = iop->_ptr)) <= 0)  /* full buf */
83 	                if (_xflsbuf(iop) == EOF)
84 	                        return (count - (nleft + size - 1)/size);
85 	        n = MIN(nleft, n);
86 	        (void) memcpy((char *) cptr, ptr, n);
87 	        iop->_cnt -= n;
88 	        iop->_ptr += n;
89 	        _BUFSYNC(iop);
90 		/* done; flush if linebuffered with a newline */
91 	        if ((nleft -= n) == 0)  {
92 			if (iop->_flag & (_IOLBF | _IONBF)) {
93 	               		if ((iop->_flag & _IONBF) || (memchr(prev_ptr,
94 					'\n',iop->_ptr - prev_ptr) != NULL))  {
95 				     	(void) _xflsbuf(iop);
96 				}
97 			}
98 	                return (count);
99 	        }
100 	}
101 }
102