1 /* 2 * atoint - convert an ascii string to a signed long, with error checking 3 */ 4 #include <config.h> 5 #include <sys/types.h> 6 #include <ctype.h> 7 8 #include "ntp_types.h" 9 #include "ntp_stdlib.h" 10 11 int atoint(const char * str,long * ival)12atoint( 13 const char *str, 14 long *ival 15 ) 16 { 17 register long u; 18 register const char *cp; 19 register int isneg; 20 register int oflow_digit; 21 22 cp = str; 23 24 if (*cp == '-') { 25 cp++; 26 isneg = 1; 27 oflow_digit = '8'; 28 } else { 29 isneg = 0; 30 oflow_digit = '7'; 31 } 32 33 if (*cp == '\0') 34 return 0; 35 36 u = 0; 37 while (*cp != '\0') { 38 if (!isdigit((unsigned char)*cp)) 39 return 0; 40 if (u > 214748364 || (u == 214748364 && *cp > oflow_digit)) 41 return 0; /* overflow */ 42 u = (u << 3) + (u << 1); 43 u += *cp++ - '0'; /* ascii dependent */ 44 } 45 46 if (isneg) 47 *ival = -u; 48 else 49 *ival = u; 50 return 1; 51 } 52