inline bool is_valid_utf8()

in include/ylt/standalone/cinatra/utils.hpp [218:258]

• 40 lines of code
• 28 McCabe index (conditional complexity)

inline bool is_valid_utf8(unsigned char *s, size_t length) {
  for (unsigned char *e = s + length; s != e;) {
    if (s + 4 <= e && ((*(uint32_t *)s) & 0x80808080) == 0) {
      s += 4;
    }
    else {
      while (!(*s & 0x80)) {
        if (++s == e) {
          return true;
        }
      }

      if ((s[0] & 0x60) == 0x40) {
        if (s + 1 >= e || (s[1] & 0xc0) != 0x80 || (s[0] & 0xfe) == 0xc0) {
          return false;
        }
        s += 2;
      }
      else if ((s[0] & 0xf0) == 0xe0) {
        if (s + 2 >= e || (s[1] & 0xc0) != 0x80 || (s[2] & 0xc0) != 0x80 ||
            (s[0] == 0xe0 && (s[1] & 0xe0) == 0x80) ||
            (s[0] == 0xed && (s[1] & 0xe0) == 0xa0)) {
          return false;
        }
        s += 3;
      }
      else if ((s[0] & 0xf8) == 0xf0) {
        if (s + 3 >= e || (s[1] & 0xc0) != 0x80 || (s[2] & 0xc0) != 0x80 ||
            (s[3] & 0xc0) != 0x80 || (s[0] == 0xf0 && (s[1] & 0xf0) == 0x80) ||
            (s[0] == 0xf4 && s[1] > 0x8f) || s[0] > 0xf4) {
          return false;
        }
        s += 4;
      }
      else {
        return false;
      }
    }
  }
  return true;
}