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1.1 root 1: /*-
2: * Copyright (c) 1990 The Regents of the University of California.
3: * 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. All advertising materials mentioning features or use of this software
14: * must display the following acknowledgement:
15: * This product includes software developed by the University of
16: * California, Berkeley and its contributors.
17: * 4. Neither the name of the University nor the names of its contributors
18: * may be used to endorse or promote products derived from this software
19: * without specific prior written permission.
20: *
21: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31: * SUCH DAMAGE.
32: */
33:
34: #if defined(LIBC_SCCS) && !defined(lint)
35: static char sccsid[] = "@(#)strtol.c 5.4 (Berkeley) 2/23/91";
36: #endif /* LIBC_SCCS and not lint */
37:
38: #include <limits.h>
39: #include <ctype.h>
40: #include <errno.h>
41: #include <stdlib.h>
42:
43:
44: /*
45: * Convert a string to a long integer.
46: *
47: * Ignores `locale' stuff. Assumes that the upper and lower case
48: * alphabets and digits are each contiguous.
49: */
50: long
51: strtol(nptr, endptr, base)
52: const char *nptr;
53: char **endptr;
54: register int base;
55: {
56: register const char *s = nptr;
57: register unsigned long acc;
58: register int c;
59: register unsigned long cutoff;
60: register int neg = 0, any, cutlim;
61:
62: /*
63: * Skip white space and pick up leading +/- sign if any.
64: * If base is 0, allow 0x for hex and 0 for octal, else
65: * assume decimal; if base is already 16, allow 0x.
66: */
67: do {
68: c = *s++;
69: } while (isspace(c));
70: if (c == '-') {
71: neg = 1;
72: c = *s++;
73: } else if (c == '+')
74: c = *s++;
75: if ((base == 0 || base == 16) &&
76: c == '0' && (*s == 'x' || *s == 'X')) {
77: c = s[1];
78: s += 2;
79: base = 16;
80: }
81: if (base == 0)
82: base = c == '0' ? 8 : 10;
83:
84: /*
85: * Compute the cutoff value between legal numbers and illegal
86: * numbers. That is the largest legal value, divided by the
87: * base. An input number that is greater than this value, if
88: * followed by a legal input character, is too big. One that
89: * is equal to this value may be valid or not; the limit
90: * between valid and invalid numbers is then based on the last
91: * digit. For instance, if the range for longs is
92: * [-2147483648..2147483647] and the input base is 10,
93: * cutoff will be set to 214748364 and cutlim to either
94: * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
95: * a value > 214748364, or equal but the next digit is > 7 (or 8),
96: * the number is too big, and we will return a range error.
97: *
98: * Set any if any `digits' consumed; make it negative to indicate
99: * overflow.
100: */
101: cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX;
102: cutlim = cutoff % (unsigned long)base;
103: cutoff /= (unsigned long)base;
104: for (acc = 0, any = 0;; c = *s++) {
105: if (isdigit(c))
106: c -= '0';
107: else if (isalpha(c))
108: c -= isupper(c) ? 'A' - 10 : 'a' - 10;
109: else
110: break;
111: if (c >= base)
112: break;
113: if (any < 0 || acc > cutoff || acc == cutoff && c > cutlim)
114: any = -1;
115: else {
116: any = 1;
117: acc *= base;
118: acc += c;
119: }
120: }
121: if (any < 0) {
122: acc = neg ? LONG_MIN : LONG_MAX;
123: errno = ERANGE;
124: } else if (neg)
125: acc = -acc;
126: if (endptr != 0)
127: *endptr = any ? s - 1 : (char *)nptr;
128: return (acc);
129: }
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