xref: /netbsd-src/common/lib/libc/stdlib/_strtoul.h (revision a536ee5124e62c9a0051a252f7833dc8f50f44c9)
1 /* $NetBSD: _strtoul.h,v 1.3 2012/03/22 15:57:29 christos Exp $ */
2 
3 /*-
4  * Copyright (c) 1990, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  *
31  * Original version ID:
32  * NetBSD: src/lib/libc/locale/_wcstoul.h,v 1.2 2003/08/07 16:43:03 agc Exp
33  */
34 
35 /*
36  * function template for strtoul, strtoull and strtoumax.
37  *
38  * parameters:
39  *	_FUNCNAME  : function name
40  *      __UINT     : return type
41  *      __UINT_MAX : upper limit of the return type
42  */
43 
44 __UINT
45 _FUNCNAME(const char *nptr, char **endptr, int base)
46 {
47 	const char *s;
48 	__UINT acc, cutoff;
49 	unsigned char c;
50 	int i, neg, any, cutlim;
51 
52 	_DIAGASSERT(nptr != NULL);
53 	/* endptr may be NULL */
54 
55 	/* check base value */
56 	if (base && (base < 2 || base > 36)) {
57 #if !defined(_KERNEL) && !defined(_STANDALONE)
58 		errno = EINVAL;
59 		return(0);
60 #else
61 		panic("%s: invalid base %d", __func__, base);
62 #endif
63 	}
64 
65 	/*
66 	 * Skip white space and pick up leading +/- sign if any.
67 	 * If base is 0, allow 0x for hex and 0 for octal, else
68 	 * assume decimal; if base is already 16, allow 0x.
69 	 */
70 	s = nptr;
71 	do {
72 		c = *s++;
73 	} while (isspace(c));
74 	if (c == '-') {
75 		neg = 1;
76 		c = *s++;
77 	} else {
78 		neg = 0;
79 		if (c == '+')
80 			c = *s++;
81 	}
82 	if ((base == 0 || base == 16) &&
83 	    c == '0' && (*s == 'x' || *s == 'X')) {
84 		c = s[1];
85 		s += 2;
86 		base = 16;
87 	}
88 	if (base == 0)
89 		base = (c == '0' ? 8 : 10);
90 
91 	/*
92 	 * See strtol for comments as to the logic used.
93 	 */
94 	cutoff = ((__UINT)__UINT_MAX / (__UINT)base);
95 	cutlim = (int)((__UINT)__UINT_MAX % (__UINT)base);
96 	for (acc = 0, any = 0;; c = *s++) {
97 		if (isdigit(c))
98 			i = c - '0';
99 		else if (isalpha(c))
100 			i = c - (isupper(c) ? 'A' - 10 : 'a' - 10);
101 		else
102 			break;
103 		if (i >= base)
104 			break;
105 		if (any < 0)
106 			continue;
107 		if (acc > cutoff || (acc == cutoff && i > cutlim)) {
108 			acc = __UINT_MAX;
109 #if !defined(_KERNEL) && !defined(_STANDALONE)
110 			any = -1;
111 			errno = ERANGE;
112 #else
113 			any = 0;
114 			break;
115 #endif
116 		} else {
117 			any = 1;
118 			acc *= (__UINT)base;
119 			acc += i;
120 		}
121 	}
122 	if (neg && any > 0)
123 		acc = -acc;
124 	if (endptr != NULL)
125 		/* LINTED interface specification */
126 		*endptr = __UNCONST(any ? s - 1 : nptr);
127 	return(acc);
128 }
129