#include <string.h>

char *strncpy(char *s1, const char *s2, size_t n) {
	char * rc = s1;
	while ( (n > 0) && (*s1++ = *s2++) ) {
		/* Cannot do "n--" in the conditional as size_t is unsigned and we have
		 * to check it again for >0 in the next loop below, so we must not risk
		 * underflow.
		 */
		--n;
	}
	/* Checking against 1 as we missed the last --n in the loop above. */
	while (n-- > 1) {
		*s1++ = '\0';
	}
	return rc;
}