xref: /titanic_41/usr/src/lib/libbc/libc/stdio/common/fgets.c (revision ae115bc77f6fcde83175c75b4206dc2e50747966)
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 3.3 */
31 
32 /*LINTLIBRARY*/
33 /*
34  * This version reads directly from the buffer rather than looping on getc.
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 #include <stdio.h>
39 #include "stdiom.h"
40 
41 #define MIN(x, y)	(x < y ? x : y)
42 
43 extern int _filbuf();
44 extern char *memccpy();
45 
46 char *
47 fgets(ptr, size, iop)
48 char *ptr;
49 register int size;
50 register FILE *iop;
51 {
52 	char *p, *ptr0 = ptr;
53 	register int n;
54 
55 	if ( !(iop->_flag & (_IOREAD|_IORW)) ) {
56 		iop->_flag |= _IOERR;
57 		return (NULL);
58 	}
59 
60 	for (size--; size > 0; size -= n) {
61 		if (iop->_cnt <= 0) { /* empty buffer */
62 			if (_filbuf(iop) == EOF) {
63 				if (ptr0 == ptr)
64 					return (NULL);
65 				break; /* no more data */
66 			}
67 			iop->_ptr--;
68 			iop->_cnt++;
69 		}
70 		n = MIN(size, iop->_cnt);
71 		if ((p = memccpy(ptr, (char *) iop->_ptr, '\n', n)) != NULL)
72 			n = p - ptr;
73 		ptr += n;
74 		iop->_cnt -= n;
75 		iop->_ptr += n;
76 		_BUFSYNC(iop);
77 		if (p != NULL)
78 			break; /* found '\n' in buffer */
79 	}
80 	*ptr = '\0';
81 	return (ptr0);
82 }
83