xref: /freebsd/lib/libc/iconv/_strtoul.h (revision 2b15cb3d0922bd70ea592f0da9b4a5b167f4d53f)
1 /* $FreeBSD$ */
2 /* $NetBSD: _strtoul.h,v 1.1 2008/08/20 12:42:26 joerg Exp $ */
3 
4 /*-
5  * Copyright (c) 1990, 1993
6  *	The Regents of the University of California.  All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  *
32  * Original version ID:
33  * NetBSD: src/lib/libc/locale/_wcstoul.h,v 1.2 2003/08/07 16:43:03 agc Exp
34  */
35 
36 /*
37  * function template for strtoul, strtoull and strtoumax.
38  *
39  * parameters:
40  *	_FUNCNAME  : function name
41  *      __UINT     : return type
42  *      __UINT_MAX : upper limit of the return type
43  */
44 
45 __UINT
46 _FUNCNAME(const char *nptr, char **endptr, int base)
47 {
48 	const char *s;
49 	__UINT acc, cutoff;
50 	unsigned char c;
51 	int any, cutlim, i, neg;
52 
53 	/* check base value */
54 	if (base && (base < 2 || base > 36)) {
55 #if !defined(_KERNEL) && !defined(_STANDALONE)
56 		errno = EINVAL;
57 		return (0);
58 #else
59 		panic("%s: invalid base %d", __func__, base);
60 #endif
61 	}
62 
63 	/*
64 	 * Skip white space and pick up leading +/- sign if any.
65 	 * If base is 0, allow 0x for hex and 0 for octal, else
66 	 * assume decimal; if base is already 16, allow 0x.
67 	 */
68 	s = nptr;
69 	do {
70 		c = *s++;
71 	} while (isspace(c));
72 	if (c == '-') {
73 		neg = 1;
74 		c = *s++;
75 	} else {
76 		neg = 0;
77 		if (c == '+')
78 			c = *s++;
79 	}
80 	if ((base == 0 || base == 16) &&
81 	    c == '0' && (*s == 'x' || *s == 'X')) {
82 		c = s[1];
83 		s += 2;
84 		base = 16;
85 	}
86 	if (base == 0)
87 		base = (c == '0' ? 8 : 10);
88 
89 	/*
90 	 * See strtol for comments as to the logic used.
91 	 */
92 	cutoff = __UINT_MAX / (__UINT)base;
93 	cutlim = (int)(__UINT_MAX % (__UINT)base);
94 	for (acc = 0, any = 0;; c = *s++) {
95 		if (isdigit(c))
96 			i = c - '0';
97 		else if (isalpha(c))
98 			i = c - (isupper(c) ? 'A' - 10 : 'a' - 10);
99 		else
100 			break;
101 		if (i >= base)
102 			break;
103 		if (any < 0)
104 			continue;
105 		if (acc > cutoff || (acc == cutoff && i > cutlim)) {
106 			acc = __UINT_MAX;
107 #if !defined(_KERNEL) && !defined(_STANDALONE)
108 			any = -1;
109 			errno = ERANGE;
110 #else
111 			any = 0;
112 			break;
113 #endif
114 		} else {
115 			any = 1;
116 			acc *= (__UINT)base;
117 			acc += i;
118 		}
119 	}
120 	if (neg && any > 0)
121 		acc = -acc;
122 	if (endptr != NULL)
123 		/* LINTED interface specification */
124 		*endptr = __DECONST(void *, any ? s - 1 : nptr);
125 	return (acc);
126 }
127