xref: /titanic_41/usr/src/lib/libbc/libc/gen/common/atoi.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 /*      Copyright (c) 1984 AT&T */
23 /*        All Rights Reserved   */
24 
25 #pragma ident	"%Z%%M%	%I%	%E% SMI"  /* from S5R2 2.1 */
26 
27 /*LINTLIBRARY*/
28 #include <ctype.h>
29 
30 #define ATOI
31 
32 #ifdef	ATOI
33 typedef int TYPE;
34 #define NAME	atoi
35 #else
36 typedef long TYPE;
37 #define NAME	atol
38 #endif
39 
40 TYPE
NAME(p)41 NAME(p)
42 register char *p;
43 {
44 	register TYPE n;
45 	register int c, neg = 0;
46 
47 	if (!isdigit(c = *p)) {
48 		while (isspace(c))
49 			c = *++p;
50 		switch (c) {
51 		case '-':
52 			neg++;
53 		case '+': /* fall-through */
54 			c = *++p;
55 		}
56 		if (!isdigit(c))
57 			return (0);
58 	}
59 	for (n = '0' - c; isdigit(c = *++p); ) {
60 		n *= 10; /* two steps to avoid unnecessary overflow */
61 		n += '0' - c; /* accum neg to avoid surprises at MAX */
62 	}
63 	return (neg ? n : -n);
64 }
65