| 1 | /*
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| 2 | * (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
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| 3 | * See the copyright notice in the ACK home directory, in the file "Copyright".
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| 4 | */
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| 5 | /* $Header: /cvsup/minix/src/lib/ansi/strtol.c,v 1.1.1.1 2005/04/21 14:56:06 beng Exp $ */
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| 6 |
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| 7 | #include <ctype.h>
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| 8 | #include <errno.h>
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| 9 | #include <limits.h>
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| 10 | #include <stdlib.h>
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| 11 |
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| 12 | static unsigned long
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| 13 | string2long(register const char *nptr, char **endptr,
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| 14 | int base, int is_signed);
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| 15 |
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| 16 | long int
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| 17 | strtol(register const char *nptr, char **endptr, int base)
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| 18 | {
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| 19 | return (signed long)string2long(nptr, endptr, base, 1);
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| 20 | }
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| 21 |
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| 22 | unsigned long int
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| 23 | strtoul(register const char *nptr, char **endptr, int base)
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| 24 | {
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| 25 | return (unsigned long)string2long(nptr, endptr, base, 0);
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| 26 | }
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| 27 |
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| 28 | #define between(a, c, z) ((unsigned) ((c) - (a)) <= (unsigned) ((z) - (a)))
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| 29 |
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| 30 | static unsigned long
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| 31 | string2long(register const char *nptr, char ** const endptr,
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| 32 | int base, int is_signed)
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| 33 | {
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| 34 | register unsigned int v;
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| 35 | register unsigned long val = 0;
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| 36 | register int c;
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| 37 | int ovfl = 0, sign = 1;
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| 38 | const char *startnptr = nptr, *nrstart;
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| 39 |
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| 40 | if (endptr) *endptr = (char *)nptr;
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| 41 | while (isspace(*nptr)) nptr++;
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| 42 | c = *nptr;
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| 43 |
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| 44 | if (c == '-' || c == '+') {
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| 45 | if (c == '-') sign = -1;
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| 46 | nptr++;
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| 47 | }
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| 48 | nrstart = nptr; /* start of the number */
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| 49 |
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| 50 | /* When base is 0, the syntax determines the actual base */
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| 51 | if (base == 0)
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| 52 | if (*nptr == '0')
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| 53 | if (*++nptr == 'x' || *nptr == 'X') {
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| 54 | base = 16;
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| 55 | nptr++;
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| 56 | }
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| 57 | else base = 8;
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| 58 | else base = 10;
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| 59 | else if (base==16 && *nptr=='0' && (*++nptr =='x' || *nptr =='X'))
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| 60 | nptr++;
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| 61 |
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| 62 | for (;;) {
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| 63 | c = *nptr;
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| 64 | if (between('0', c, '9')) {
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| 65 | v = c - '0';
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| 66 | } else
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| 67 | if (between('a', c, 'z')) {
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| 68 | v = c - 'a' + 0xa;
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| 69 | } else
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| 70 | if (between('A', c, 'Z')) {
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| 71 | v = c - 'A' + 0xA;
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| 72 | } else {
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| 73 | break;
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| 74 | }
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| 75 | if (v >= base) break;
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| 76 | if (val > (ULONG_MAX - v) / base) ovfl++;
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| 77 | val = (val * base) + v;
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| 78 | nptr++;
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| 79 | }
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| 80 | if (endptr) {
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| 81 | if (nrstart == nptr) *endptr = (char *)startnptr;
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| 82 | else *endptr = (char *)nptr;
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| 83 | }
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| 84 |
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| 85 | if (!ovfl) {
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| 86 | /* Overflow is only possible when converting a signed long. */
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| 87 | if (is_signed
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| 88 | && ( (sign < 0 && val > -(unsigned long)LONG_MIN)
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| 89 | || (sign > 0 && val > LONG_MAX)))
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| 90 | ovfl++;
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| 91 | }
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| 92 |
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| 93 | if (ovfl) {
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| 94 | errno = ERANGE;
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| 95 | if (is_signed)
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| 96 | if (sign < 0) return LONG_MIN;
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| 97 | else return LONG_MAX;
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| 98 | else return ULONG_MAX;
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| 99 | }
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| 100 | return (long) sign * val;
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| 101 | }
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