96 lines
2.1 KiB
C
96 lines
2.1 KiB
C
/*
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* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
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* See the copyright notice in the ACK home directory, in the file "Copyright".
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*/
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/* $Header$ */
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#include <ctype.h>
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#include <errno.h>
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#include <limits.h>
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#include <stdlib.h>
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static unsigned long
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string2long(register const char *nptr, char **endptr,
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int base, int is_signed);
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long int
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strtol(register const char *nptr, char **endptr, int base)
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{
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return (signed long)string2long(nptr, endptr, base, 1);
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}
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unsigned long int
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strtoul(register const char *nptr, char **endptr, int base)
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{
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return (unsigned long)string2long(nptr, endptr, base, 0);
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}
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static unsigned long
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string2long(register const char *nptr, char ** const endptr,
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int base, int is_signed)
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{
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register int v;
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register unsigned long val = 0;
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register int c;
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int ovfl = 0, sign = 1;
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const char *startnptr = nptr, *nrstart;
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if (endptr) *endptr = (char *)nptr;
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while (isspace(*nptr)) nptr++;
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c = *nptr;
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if (c == '-' || c == '+') {
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if (c == '-') sign = -1;
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nptr++;
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}
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nrstart = nptr; /* start of the number */
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/* When base is 0, the syntax determines the actual base */
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if (base == 0)
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if (*nptr == '0')
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if (*++nptr == 'x' || *nptr == 'X') {
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base = 16;
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nptr++;
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}
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else base = 8;
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else base = 10;
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else if (base==16 && *nptr=='0' && (*++nptr =='x' || *nptr =='X'))
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nptr++;
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while (isdigit(c = *nptr) || isalpha(c)) {
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if (!ovfl) {
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if (isalpha(c))
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v = 10 + (isupper(c) ? c - 'A' : c - 'a');
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else
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v = c - '0';
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if (v >= base) break;
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if (val > (ULONG_MAX - v) / base) ovfl++;
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val = (val * base) + v;
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}
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nptr++;
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}
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if (endptr) {
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if (nrstart == nptr) *endptr = (char *)startnptr;
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else *endptr = (char *)nptr;
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}
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if (!ovfl) {
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/* Overflow is only possible when converting a signed long.
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* val is unsigned long, so -LONG_MIN is converted to
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* unsigned long.
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*/
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if (is_signed
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&& ( (sign < 0 && val > -LONG_MIN)
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|| (sign > 0 && val > LONG_MAX)))
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ovfl++;
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}
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if (ovfl) {
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errno = ERANGE;
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if (is_signed)
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if (sign < 0) return LONG_MIN;
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else return LONG_MAX;
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else return ULONG_MAX;
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}
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return (long) sign * val;
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}
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