Function IsValidCodepoint

external/sentencepiece/src/util.h:165–167

inline bool IsTrailByte(char x) { return static_cast<signed char>(x) < -0x40; }

inline bool IsValidCodepoint(char32 c) {
  return (static_cast<uint32_t>(c) < 0xD800) || (c >= 0xE000 && c <= 0x10FFFF);
}

bool IsStructurallyValid(absl::string_view str);