1/* $FreeBSD$ */
2/* $NetBSD: _strtol.h,v 1.2 2009/05/20 22:03:29 christos 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/_wcstol.h,v 1.2 2003/08/07 16:43:03 agc Exp
34 */
35
36/*
37 * function template for strtol, strtoll and strtoimax.
38 *
39 * parameters:
40 *	_FUNCNAME : function name
41 *      __INT     : return type
42 *      __INT_MIN : lower limit of the return type
43 *      __INT_MAX : upper limit of the return type
44 */
45
46__INT
47_FUNCNAME(const char *nptr, char **endptr, int base)
48{
49	const char *s;
50	__INT acc, cutoff;
51	unsigned char c;
52	int any, cutlim, i, neg;
53
54	/* check base value */
55	if (base && (base < 2 || base > 36)) {
56#if !defined(_KERNEL) && !defined(_STANDALONE)
57		errno = EINVAL;
58		if (endptr != NULL)
59			/* LINTED interface specification */
60			*endptr = __DECONST(void *, nptr);
61		return (0);
62#else
63		panic("%s: invalid base %d", __func__, base);
64#endif
65	}
66
67	/*
68	 * Skip white space and pick up leading +/- sign if any.
69	 * If base is 0, allow 0x for hex and 0 for octal, else
70	 * assume decimal; if base is already 16, allow 0x.
71	 */
72	s = nptr;
73	do {
74		c = *s++;
75	} while (isspace(c));
76	if (c == '-') {
77		neg = 1;
78		c = *s++;
79	} else {
80		neg = 0;
81		if (c == '+')
82			c = *s++;
83	}
84	if ((base == 0 || base == 16) &&
85	    c == '0' && (*s == 'x' || *s == 'X')) {
86		c = s[1];
87		s += 2;
88		base = 16;
89	}
90	if (base == 0)
91		base = (c == '0' ? 8 : 10);
92
93	/*
94	 * Compute the cutoff value between legal numbers and illegal
95	 * numbers.  That is the largest legal value, divided by the
96	 * base.  An input number that is greater than this value, if
97	 * followed by a legal input character, is too big.  One that
98	 * is equal to this value may be valid or not; the limit
99	 * between valid and invalid numbers is then based on the last
100	 * digit.  For instance, if the range for longs is
101	 * [-2147483648..2147483647] and the input base is 10,
102	 * cutoff will be set to 214748364 and cutlim to either
103	 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
104	 * a value > 214748364, or equal but the next digit is > 7 (or 8),
105	 * the number is too big, and we will return a range error.
106	 *
107	 * Set any if any `digits' consumed; make it negative to indicate
108	 * overflow.
109	 */
110	cutoff = (neg ? __INT_MIN : __INT_MAX);
111	cutlim = (int)(cutoff % base);
112	cutoff /= base;
113	if (neg) {
114		if (cutlim > 0) {
115			cutlim -= base;
116			cutoff += 1;
117		}
118		cutlim = -cutlim;
119	}
120	for (acc = 0, any = 0;; c = *s++) {
121		if (isdigit(c))
122			i = c - '0';
123		else if (isalpha(c))
124			i = c - (isupper(c) ? 'A' - 10 : 'a' - 10);
125		else
126			break;
127		if (i >= base)
128			break;
129		if (any < 0)
130			continue;
131		if (neg) {
132			if (acc < cutoff || (acc == cutoff && i > cutlim)) {
133				acc = __INT_MIN;
134#if !defined(_KERNEL) && !defined(_STANDALONE)
135				any = -1;
136				errno = ERANGE;
137#else
138				any = 0;
139				break;
140#endif
141			} else {
142				any = 1;
143				acc *= base;
144				acc -= i;
145			}
146		} else {
147			if (acc > cutoff || (acc == cutoff && i > cutlim)) {
148				acc = __INT_MAX;
149#if !defined(_KERNEL) && !defined(_STANDALONE)
150				any = -1;
151				errno = ERANGE;
152#else
153				any = 0;
154				break;
155#endif
156			} else {
157				any = 1;
158				acc *= base;
159				acc += i;
160			}
161		}
162	}
163	if (endptr != NULL)
164		/* LINTED interface specification */
165		*endptr = __DECONST(void *, any ? s - 1 : nptr);
166	return(acc);
167}
168