/contrib/ntp/libntp/atoint.c
https://bitbucket.org/freebsd/freebsd-head/ · C · 50 lines · 40 code · 7 blank · 3 comment · 14 complexity · b1c311470cb2499f9b47d124b6953989 MD5 · raw file
- /*
- * atoint - convert an ascii string to a signed long, with error checking
- */
- #include <sys/types.h>
- #include <ctype.h>
- #include "ntp_types.h"
- #include "ntp_stdlib.h"
- int
- atoint(
- const char *str,
- long *ival
- )
- {
- register long u;
- register const char *cp;
- register int isneg;
- register int oflow_digit;
- cp = str;
- if (*cp == '-') {
- cp++;
- isneg = 1;
- oflow_digit = '8';
- } else {
- isneg = 0;
- oflow_digit = '7';
- }
- if (*cp == '\0')
- return 0;
- u = 0;
- while (*cp != '\0') {
- if (!isdigit((int)*cp))
- return 0;
- if (u > 214748364 || (u == 214748364 && *cp > oflow_digit))
- return 0; /* overflow */
- u = (u << 3) + (u << 1);
- u += *cp++ - '0'; /* ascii dependent */
- }
- if (isneg)
- *ival = -u;
- else
- *ival = u;
- return 1;
- }