xref: /titanic_41/usr/src/lib/libc/port/gen/atoi.c (revision 505d05c73a6e56769f263d4803b22eddd168ee24)
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 2004 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 /*	Copyright (c) 1988 AT&T	*/
30 /*	  All Rights Reserved  	*/
31 
32 
33 #include "synonyms.h"
34 #include <ctype.h>
35 #include <sys/types.h>
36 #include <stdlib.h>
37 
38 #define	ATOI
39 
40 #ifdef	ATOI
41 typedef int TYPE;
42 #define	NAME	atoi
43 #else
44 typedef long TYPE;
45 #define	NAME	atol
46 #endif
47 
48 TYPE
49 NAME(const char *p)
50 {
51 	TYPE n;
52 	int c, neg = 0;
53 	unsigned char	*up = (unsigned char *)p;
54 
55 	if (!isdigit(c = *up)) {
56 		while (isspace(c))
57 			c = *++up;
58 		switch (c) {
59 		case '-':
60 			neg++;
61 			/* FALLTHROUGH */
62 		case '+':
63 			c = *++up;
64 		}
65 		if (!isdigit(c))
66 			return (0);
67 	}
68 	for (n = '0' - c; isdigit(c = *++up); ) {
69 		n *= 10; /* two steps to avoid unnecessary overflow */
70 		n += '0' - c; /* accum neg to avoid surprises at MAX */
71 	}
72 	return (neg ? n : -n);
73 }
74