Re: generic strncpy - off-by-one error

[Daniel Forrest <forrest@lmcg.wisc.edu>]

On Sat, Aug 16, 2003 at 11:19:30AM +0200, Peter Kjellerstedt wrote:
> 
> Actually, it should be:
> 
> 	while (count && ((long)tmp & (sizeof(long) - 1)))
> 

Oops, you're right, I forgot that the count could be small.

But, now that I think of it, maybe this would be best...

 char *strncpy(char *dest, const char *src, size_t count)
 {
 	char *tmp = dest;
 
 	while (count && *src) {
 		*tmp++ = *src++;
 		count--;
 	}
 
-	if (count) {
+	if (count >= sizeof(long)) {
 		size_t count2;
 
-		while (count && ((long)tmp & (sizeof(long) - 1))) {
+		while ((long)tmp & (sizeof(long) - 1)) {
 			*tmp++ = '\0';
 			count--;
 		}
 
 		count2 = count / sizeof(long);
 		while (count2) {
 			*((long *)tmp)++ = '\0';
 			count2--;
 		}
 
 		count &= (sizeof(long) - 1);
-		while (count) {
-			*tmp++ = '\0';
-			count--;
-		}
+	}
+
+	while (count) {
+		*tmp++ = '\0';
+		count--;
 	}
 
 	return dest;
 }

-- 
Dan