xref: /dragonfly/lib/libc/stdlib/_strtol.h (revision d9d30518)
1 /*-
2  * Copyright (c) 1990, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  * Original version ID:
30  * $NetBSD: src/lib/libc/locale/_wcstol.h,v 1.2 2003/08/07 16:43:03 agc Exp $
31  */
32 
33 #define _LOCALE_NAME(func) func ## _l
34 #define _MAKE_LOCALE_NAME(func) _LOCALE_NAME(func)
35 #define _FUNCNAME_L _MAKE_LOCALE_NAME(_FUNCNAME)
36 
37 /*
38  * function template for strtol, strtoll and strtoimax.
39  *
40  * parameters:
41  *	_FUNCNAME : function name
42  *      __INT     : return type
43  *      __INT_MIN : lower limit of the return type
44  *      __INT_MAX : upper limit of the return type
45  */
46 __INT
47 _FUNCNAME_L(const char * __restrict nptr, char ** __restrict endptr, int base,
48 		locale_t locale)
49 {
50 	const char *s;
51 	__INT acc, cutoff;
52 	char c;
53 	int i, neg, any, cutlim;
54 
55 	_DIAGASSERT(nptr != NULL);
56 	/* endptr may be NULL */
57 
58 	FIX_LOCALE(locale);
59 
60 	/* check base value */
61 	if (base && (base < 2 || base > 36)) {
62 		errno = EINVAL;
63 		return(0);
64 	}
65 
66 	/*
67 	 * Skip white space and pick up leading +/- sign if any.
68 	 * If base is 0, allow 0x for hex and 0 for octal, else
69 	 * assume decimal; if base is already 16, allow 0x.
70 	 */
71 	s = nptr;
72 	do {
73 		c = *s++;
74 	} while (isspace_l((unsigned char)c, locale));
75 	if (c == '-') {
76 		neg = 1;
77 		c = *s++;
78 	} else {
79 		neg = 0;
80 		if (c == '+')
81 			c = *s++;
82 	}
83 	if ((base == 0 || base == 16) &&
84 	    c == '0' &&
85 	    (*s == 'x' || *s == 'X') &&
86 	    isxdigit_l((unsigned char)s[1], locale))
87 	{
88 		c = s[1];
89 		s += 2;
90 		base = 16;
91 	}
92 	if (base == 0)
93 		base = c == '0' ? 8 : 10;
94 
95 	/*
96 	 * Compute the cutoff value between legal numbers and illegal
97 	 * numbers.  That is the largest legal value, divided by the
98 	 * base.  An input number that is greater than this value, if
99 	 * followed by a legal input character, is too big.  One that
100 	 * is equal to this value may be valid or not; the limit
101 	 * between valid and invalid numbers is then based on the last
102 	 * digit.  For instance, if the range for longs is
103 	 * [-2147483648..2147483647] and the input base is 10,
104 	 * cutoff will be set to 214748364 and cutlim to either
105 	 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
106 	 * a value > 214748364, or equal but the next digit is > 7 (or 8),
107 	 * the number is too big, and we will return a range error.
108 	 *
109 	 * Set any if any `digits' consumed; make it negative to indicate
110 	 * overflow.
111 	 */
112 	cutoff = neg ? __INT_MIN : __INT_MAX;
113 	cutlim = (int)(cutoff % base);
114 	cutoff /= base;
115 	if (neg) {
116 		if (cutlim > 0) {
117 			cutlim -= base;
118 			cutoff += 1;
119 		}
120 		cutlim = -cutlim;
121 	}
122 	for (acc = 0, any = 0;; c = *s++) {
123 		if (!isascii(c))
124 			break;
125 		if (isdigit(c))
126 			i = c - '0';
127 		else if (isalpha(c))
128 			i = c - (isupper(c) ? 'A' - 10 : 'a' - 10);
129 		else
130 			break;
131 		if (i >= base)
132 			break;
133 		if (any < 0)
134 			continue;
135 		if (neg) {
136 			if (acc < cutoff || (acc == cutoff && i > cutlim)) {
137 				any = -1;
138 				acc = __INT_MIN;
139 				errno = ERANGE;
140 			} else {
141 				any = 1;
142 				acc *= base;
143 				acc -= i;
144 			}
145 		} else {
146 			if (acc > cutoff || (acc == cutoff && i > cutlim)) {
147 				any = -1;
148 				acc = __INT_MAX;
149 				errno = ERANGE;
150 			} else {
151 				any = 1;
152 				acc *= base;
153 				acc += i;
154 			}
155 		}
156 	}
157 	if (endptr != NULL)
158 		/* LINTED interface specification */
159 		*endptr = __DECONST(char *, (any ? s - 1 : nptr));
160 	return(acc);
161 }
162 
163 __INT
164 _FUNCNAME(const char * __restrict nptr, char ** __restrict endptr, int base)
165 {
166 	return _FUNCNAME_L(nptr, endptr, base, __get_locale());
167 }
168