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15637ed4 RG |
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) | |
49b73c4d | 127 | *endptr = any ? (char *)s - 1 : (char *)nptr; |
15637ed4 RG |
128 | return (acc); |
129 | } |