C string view + basename()

sv.c

// string view
struct sv {
  const char *begin;
  const char *end;
};

const char *s_dot = ".";

// Custom basename returning string view
struct sv basename(const char *path) {
  if (*path == 0) {
    return (struct sv){s_dot, s_dot + 1};
  }

  struct sv prev_sv = {path, path + 1};
  struct sv sv = {path, path + 1};

  do {
    if (*path == '\\' || *path == '/') {
      prev_sv = sv;
      sv.begin = path + 1;
    }
    sv.end = ++path;
  } while (*path != 0);
  sv.end = path;

  return sv.end - sv.begin > 0 ? sv : prev_sv;
}

Print string view using %.*s formatting:

struct sv filename_sv = basename(filepath);
printf("%.*s\n", (i32)(filename_sv.end - filename_sv.begin), filename_sv.begin);