xref: /illumos-gate/usr/src/lib/libc/port/gen/atoll.c (revision a5f69788de7ac07553de47f7fec8c05a9a94c105)
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 #pragma weak atoll = _atoll
34 
35 #include "synonyms.h"
36 #include <ctype.h>
37 #include <sys/types.h>
38 #include <stdlib.h>
39 
40 #define	ATOLL
41 
42 #if defined	ATOI
43 typedef int TYPE;
44 #define	NAME	atoi
45 #elif defined ATOL
46 typedef long TYPE;
47 #define	NAME	atol
48 #else
49 typedef longlong_t TYPE;
50 #define	NAME	atoll
51 #endif
52 
53 TYPE
54 NAME(const char *p)
55 {
56 	TYPE n;
57 	int c, neg = 0;
58 	unsigned char	*up = (unsigned char *)p;
59 
60 	if (!isdigit(c = *up)) {
61 		while (isspace(c))
62 			c = *++up;
63 		switch (c) {
64 		case '-':
65 			neg++;
66 			/* FALLTHROUGH */
67 		case '+':
68 			c = *++up;
69 		}
70 		if (!isdigit(c))
71 			return (0);
72 	}
73 	for (n = '0' - c; isdigit(c = *++up); ) {
74 		n *= 10; /* two steps to avoid unnecessary overflow */
75 		n += '0' - c; /* accum neg to avoid surprises at MAX */
76 	}
77 	return (neg ? n : -n);
78 }
79