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freebsd/contrib/ntp/libntp/hextoint.c
1999-12-09 13:01:21 +00:00

40 lines
616 B
C

/*
* hextoint - convert an ascii string in hex to an unsigned
* long, with error checking
*/
#include <ctype.h>
#include "ntp_stdlib.h"
int
hextoint(
const char *str,
u_long *ival
)
{
register u_long u;
register const char *cp;
cp = str;
if (*cp == '\0')
return 0;
u = 0;
while (*cp != '\0') {
if (!isxdigit((int)*cp))
return 0;
if (u >= 0x10000000)
return 0; /* overflow */
u <<= 4;
if (*cp <= '9') /* very ascii dependent */
u += *cp++ - '0';
else if (*cp >= 'a')
u += *cp++ - 'a' + 10;
else
u += *cp++ - 'A' + 10;
}
*ival = u;
return 1;
}