Function valueToQuotedStringN

src/share/jsoncpp/jsoncpp.cpp:4335–4396

  return NULL;
}
static JSONCPP_STRING valueToQuotedStringN(const char* value, unsigned length) {
  if (value == NULL)
    return "";
  // Not sure how to handle unicode...
  if (strnpbrk(value, "\"\\\b\f\n\r\t", length) == NULL &&
      !containsControlCharacter0(value, length))
    return JSONCPP_STRING("\"") + value + "\"";
  // We have to walk value and escape any special characters.
  // Appending to JSONCPP_STRING is not efficient, but this should be rare.
  // (Note: forward slashes are *not* rare, but I am not escaping them.)
  JSONCPP_STRING::size_type maxsize =
      length * 2 + 3; // allescaped+quotes+NULL
  JSONCPP_STRING result;
  result.reserve(maxsize); // to avoid lots of mallocs
  result += "\"";
  char const* end = value + length;
  for (const char* c = value; c != end; ++c) {
    switch (*c) {
    case '\"':
      result += "\\\"";
      break;
    case '\\':
      result += "\\\\";
      break;
    case '\b':
      result += "\\b";
      break;
    case '\f':
      result += "\\f";
      break;
    case '\n':
      result += "\\n";
      break;
    case '\r':
      result += "\\r";
      break;
    case '\t':
      result += "\\t";
      break;
    // case '/':
    // Even though \/ is considered a legal escape in JSON, a bare
    // slash is also legal, so I see no reason to escape it.
    // (I hope I am not misunderstanding something.)
    // blep notes: actually escaping \/ may be useful in javascript to avoid </
    // sequence.
    // Should add a flag to allow this compatibility mode and prevent this
    // sequence from occurring.
    default:
      if ((isControlCharacter(*c)) || (*c == 0)) {
        JSONCPP_OSTRINGSTREAM oss;
        oss << "\\u" << std::hex << std::uppercase << std::setfill('0')
            << std::setw(4) << static_cast<int>(*c);
        result += oss.str();
      } else {
        result += *c;
      }
      break;
    }