_strtol.h revision 1.1.2.2 
1/* $NetBSD: _strtol.h,v 1.1.2.2 2008/09/18 04:54:18 wrstuden 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/_wcstol.h,v 1.2 2003/08/07 16:43:03 agc Exp
33 */
34
35/*
36 * function template for strtol, strtoll and strtoimax.
37 *
38 * parameters:
39 *	_FUNCNAME : function name
40 *      __INT     : return type
41 *      __INT_MIN : lower limit of the return type
42 *      __INT_MAX : upper limit of the return type
43 */
44
45__INT
46_FUNCNAME(const char *nptr, char **endptr, int base)
47{
48	const char *s;
49	__INT acc, cutoff;
50	unsigned char c;
51	int i, neg, any, cutlim;
52
53	_DIAGASSERT(nptr != NULL);
54	/* endptr may be NULL */
55
56	/* check base value */
57	if (base && (base < 2 || base > 36)) {
58#if !defined(_KERNEL) && !defined(_STANDALONE)
59		errno = EINVAL;
60		return(0);
61#else
62		panic("%s: invalid base %d", __func__, base);
63#endif
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(c));
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' && (*s == 'x' || *s == 'X')) {
85		c = s[1];
86		s += 2;
87		base = 16;
88	}
89	if (base == 0)
90		base = (c == '0' ? 8 : 10);
91
92	/*
93	 * Compute the cutoff value between legal numbers and illegal
94	 * numbers.  That is the largest legal value, divided by the
95	 * base.  An input number that is greater than this value, if
96	 * followed by a legal input character, is too big.  One that
97	 * is equal to this value may be valid or not; the limit
98	 * between valid and invalid numbers is then based on the last
99	 * digit.  For instance, if the range for longs is
100	 * [-2147483648..2147483647] and the input base is 10,
101	 * cutoff will be set to 214748364 and cutlim to either
102	 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
103	 * a value > 214748364, or equal but the next digit is > 7 (or 8),
104	 * the number is too big, and we will return a range error.
105	 *
106	 * Set any if any `digits' consumed; make it negative to indicate
107	 * overflow.
108	 */
109	cutoff = (neg ? __INT_MIN : __INT_MAX);
110	cutlim = (int)(cutoff % base);
111	cutoff /= base;
112	if (neg) {
113		if (cutlim > 0) {
114			cutlim -= base;
115			cutoff += 1;
116		}
117		cutlim = -cutlim;
118	}
119	for (acc = 0, any = 0;; c = *s++) {
120		if (isdigit(c))
121			i = c - '0';
122		else if (isalpha(c))
123			i = c - (isupper(c) ? 'A' - 10 : 'a' - 10);
124		else
125			break;
126		if (i >= base)
127			break;
128		if (any < 0)
129			continue;
130		if (neg) {
131			if (acc < cutoff || (acc == cutoff && i > cutlim)) {
132				acc = __INT_MIN;
133#if !defined(_KERNEL) && !defined(_STANDALONE)
134				any = -1;
135				errno = ERANGE;
136#else
137				any = 0;
138				break;
139#endif
140			} else {
141				any = 1;
142				acc *= base;
143				acc -= i;
144			}
145		} else {
146			if (acc > cutoff || (acc == cutoff && i > cutlim)) {
147				acc = __INT_MAX;
148#if !defined(_KERNEL) && !defined(_STANDALONE)
149				any = -1;
150				errno = ERANGE;
151#else
152				any = 0;
153				break;
154#endif
155			} else {
156				any = 1;
157				acc *= base;
158				acc += i;
159			}
160		}
161	}
162	if (endptr != NULL)
163		/* LINTED interface specification */
164		*endptr = __UNCONST(any ? s - 1 : nptr);
165	return(acc);
166}
167