Function EscapeInternal

internal/strings.cc:444–500

}

std::string EscapeInternal(absl::string_view src, bool escape_all_bytes,
                           char escape_quote_char) {
  std::string dest;
  // Worst case size is every byte has to be hex escaped, so 4 char for every
  // byte.
  dest.reserve(src.size() * 4);
  bool last_hex_escape = false;  // true if last output char was \xNN.
  const char* p = src.data();
  const char* end = p + src.size();
  for (; p < end; ++p) {
    unsigned char c = static_cast<unsigned char>(*p);
    bool is_hex_escape = false;
    switch (c) {
      case '\n':
        dest.append("\\n");
        break;
      case '\r':
        dest.append("\\r");
        break;
      case '\t':
        dest.append("\\t");
        break;
      case '\\':
        dest.append("\\\\");
        break;
      case '\'':
        ABSL_FALLTHROUGH_INTENDED;
      case '\"':
        ABSL_FALLTHROUGH_INTENDED;
      case '`':
        // Escape only quote chars that match escape_quote_char.
        if (escape_quote_char == 0 || c == escape_quote_char) {
          dest.push_back('\\');
        }
        dest.push_back(c);
        break;
      default:
        // Note that if we emit \xNN and the src character after that is a hex
        // digit then that digit must be escaped too to prevent it being
        // interpreted as part of the character code by C.
        if ((!escape_all_bytes || c < 0x80) &&
            (!absl::ascii_isprint(c) ||
             (last_hex_escape && absl::ascii_isxdigit(c)))) {
          dest.append("\\x");
          dest.push_back(kHexTable[c / 16]);
          dest.push_back(kHexTable[c % 16]);
          is_hex_escape = true;
        } else {
          dest.push_back(c);
          break;
        }
    }
    last_hex_escape = is_hex_escape;
  }
  dest.shrink_to_fit();
  return dest;
}