uch/uch.h

/* Include these
   #include <stdint.h>
   something with size_t defined like stddef.h or stdlib.h
 */

typedef uint32_t Uch;
typedef uint_fast8_t Ch_len;

Ch_len
ch_len_f(const char *str);

Ch_len
ch_len_b(const char *str);

Ch_len
ch_len(Uch ch);

Uch
uch(const char *str, Ch_len *len);