Annotation of src/lib/libc/stdlib/strtol.c, Revision 1.15
1.15 ! lukem 1: /* $NetBSD: strtol.c,v 1.14 1999/09/16 11:45:36 lukem Exp $ */
1.7 thorpej 2:
1.1 cgd 3: /*-
1.11 perry 4: * Copyright (c) 1990, 1993
5: * The Regents of the University of California. All rights reserved.
1.1 cgd 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. All advertising materials mentioning features or use of this software
16: * must display the following acknowledgement:
17: * This product includes software developed by the University of
18: * California, Berkeley and its contributors.
19: * 4. Neither the name of the University nor the names of its contributors
20: * may be used to endorse or promote products derived from this software
21: * without specific prior written permission.
22: *
23: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33: * SUCH DAMAGE.
34: */
35:
1.10 christos 36: #include <sys/cdefs.h>
1.1 cgd 37: #if defined(LIBC_SCCS) && !defined(lint)
1.7 thorpej 38: #if 0
1.11 perry 39: static char sccsid[] = "@(#)strtol.c 8.1 (Berkeley) 6/4/93";
1.7 thorpej 40: #else
1.15 ! lukem 41: __RCSID("$NetBSD: strtol.c,v 1.14 1999/09/16 11:45:36 lukem Exp $");
1.7 thorpej 42: #endif
1.1 cgd 43: #endif /* LIBC_SCCS and not lint */
44:
1.14 lukem 45: #include <assert.h>
1.1 cgd 46: #include <ctype.h>
47: #include <errno.h>
1.5 mycroft 48: #include <limits.h>
1.1 cgd 49: #include <stdlib.h>
50:
51:
52: /*
53: * Convert a string to a long integer.
54: *
55: * Ignores `locale' stuff. Assumes that the upper and lower case
56: * alphabets and digits are each contiguous.
57: */
58: long
59: strtol(nptr, endptr, base)
60: const char *nptr;
61: char **endptr;
1.12 mycroft 62: int base;
1.1 cgd 63: {
1.12 mycroft 64: const char *s;
65: long acc, cutoff;
66: int c;
67: int neg, any, cutlim;
1.14 lukem 68:
69: _DIAGASSERT(nptr != NULL);
70: /* endptr may be NULL */
1.1 cgd 71:
72: /*
73: * Skip white space and pick up leading +/- sign if any.
74: * If base is 0, allow 0x for hex and 0 for octal, else
75: * assume decimal; if base is already 16, allow 0x.
76: */
1.5 mycroft 77: s = nptr;
1.1 cgd 78: do {
1.9 jtc 79: c = (unsigned char) *s++;
1.1 cgd 80: } while (isspace(c));
81: if (c == '-') {
82: neg = 1;
83: c = *s++;
1.5 mycroft 84: } else {
85: neg = 0;
86: if (c == '+')
87: c = *s++;
88: }
1.1 cgd 89: if ((base == 0 || base == 16) &&
90: c == '0' && (*s == 'x' || *s == 'X')) {
91: c = s[1];
92: s += 2;
93: base = 16;
94: }
95: if (base == 0)
96: base = c == '0' ? 8 : 10;
97:
98: /*
99: * Compute the cutoff value between legal numbers and illegal
100: * numbers. That is the largest legal value, divided by the
101: * base. An input number that is greater than this value, if
102: * followed by a legal input character, is too big. One that
103: * is equal to this value may be valid or not; the limit
104: * between valid and invalid numbers is then based on the last
105: * digit. For instance, if the range for longs is
106: * [-2147483648..2147483647] and the input base is 10,
107: * cutoff will be set to 214748364 and cutlim to either
108: * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
109: * a value > 214748364, or equal but the next digit is > 7 (or 8),
110: * the number is too big, and we will return a range error.
111: *
112: * Set any if any `digits' consumed; make it negative to indicate
113: * overflow.
114: */
1.6 mycroft 115: cutoff = neg ? LONG_MIN : LONG_MAX;
1.13 christos 116: cutlim = (int)(cutoff % base);
1.6 mycroft 117: cutoff /= base;
118: if (neg) {
119: if (cutlim > 0) {
120: cutlim -= base;
121: cutoff += 1;
122: }
123: cutlim = -cutlim;
124: }
1.9 jtc 125: for (acc = 0, any = 0;; c = (unsigned char) *s++) {
1.1 cgd 126: if (isdigit(c))
127: c -= '0';
128: else if (isalpha(c))
129: c -= isupper(c) ? 'A' - 10 : 'a' - 10;
130: else
131: break;
132: if (c >= base)
133: break;
1.6 mycroft 134: if (any < 0)
135: continue;
136: if (neg) {
1.10 christos 137: if (acc < cutoff || (acc == cutoff && c > cutlim)) {
1.6 mycroft 138: any = -1;
139: acc = LONG_MIN;
140: errno = ERANGE;
141: } else {
142: any = 1;
143: acc *= base;
144: acc -= c;
145: }
146: } else {
1.10 christos 147: if (acc > cutoff || (acc == cutoff && c > cutlim)) {
1.6 mycroft 148: any = -1;
149: acc = LONG_MAX;
150: errno = ERANGE;
151: } else {
152: any = 1;
153: acc *= base;
154: acc += c;
155: }
1.1 cgd 156: }
157: }
158: if (endptr != 0)
1.13 christos 159: /* LINTED interface specification */
1.11 perry 160: *endptr = (char *)(any ? s - 1 : nptr);
1.1 cgd 161: return (acc);
162: }
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