xref: /illumos-gate/usr/src/lib/libc/port/gen/atoll.c (revision ddb365bfc9e868ad24ccdcb0dc91af18b10df082)
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 (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1988 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 #include "lint.h"
31 #include <ctype.h>
32 #include <sys/types.h>
33 #include <stdlib.h>
34 
35 #define	ATOLL
36 
37 #if defined	ATOI
38 typedef int TYPE;
39 #define	NAME	atoi
40 #elif defined ATOL
41 typedef long TYPE;
42 #define	NAME	atol
43 #else
44 typedef longlong_t TYPE;
45 #define	NAME	atoll
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