ack/lang/cem/libcc/gen/strtol.c
1990-06-25 15:59:16 +00:00

57 lines
1.2 KiB
C

/*
* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
* See the copyright notice in the ACK home directory, in the file "Copyright".
*/
/* $Header$ */
#include <ctype.h>
long int
strtol(nptr, endptr, base)
register char *nptr;
char **endptr;
{
register int v;
register long val = 0;
register int c;
int sign = 1;
char *startnptr = nptr, *nrstart;
if (endptr) *endptr = (char *)nptr;
while (isspace(*nptr)) nptr++;
c = *nptr;
if (c == '-' || c == '+') {
if (c == '-') sign = -1;
nptr++;
}
nrstart = nptr; /* start of the number */
/* When base is 0, the syntax determines the actual base */
if (base == 0)
if (*nptr == '0')
if (*++nptr == 'x' || *nptr == 'X') {
base = 16;
nptr++;
}
else base = 8;
else base = 10;
else if (base==16 && *nptr=='0' && (*++nptr =='x' || *nptr =='X'))
nptr++;
while (isdigit(c = *nptr) || isalpha(c)) {
if (isalpha(c))
v = 10 + (isupper(c) ? c - 'A' : c - 'a');
else
v = c - '0';
if (v >= base) break;
val = (val * base) + v;
nptr++;
}
if (endptr) {
if (nrstart == nptr) *endptr = (char *)startnptr;
else *endptr = (char *)nptr;
}
return (long) sign * val;
}