static String expandEscapedChars()

in spectator-api/src/main/java/com/netflix/spectator/impl/matcher/PatternUtils.java [99:158]

• 60 lines of code
• 19 McCabe index (conditional complexity)

  static String expandEscapedChars(String str) {
    StringBuilder builder = new StringBuilder();
    for (int i = 0; i < str.length(); ++i) {
      char c = str.charAt(i);
      if (c == '\\') {
        ++i;
        if (i >= str.length()) {
          throw error("dangling escape", str, i);
        }
        c = str.charAt(i);
        switch (c) {
          case 't': builder.append('\t'); break;
          case 'n': builder.append('\n'); break;
          case 'r': builder.append('\r'); break;
          case 'f': builder.append('\f'); break;
          case 'a': builder.append('\u0007'); break;
          case 'e': builder.append('\u001B'); break;
          case '0':
            int numDigits = 0;
            for (int j = i + 1; j < Math.min(i + 4, str.length()); ++j) {
              c = str.charAt(j);
              if (c >= '0' && c <= '7') {
                ++numDigits;
              } else {
                break;
              }
            }
            if (numDigits < 1 || numDigits > 3) {
              throw error("invalid octal escape sequence", str, i);
            }
            c = parse(str.substring(i + 1, i + numDigits + 1), 8, "octal", str, i);
            builder.append(c);
            i += numDigits;
            break;
          case 'x':
            if (i + 3 > str.length()) {
              throw error("invalid hexadecimal escape sequence", str, i);
            }
            c = parse(str.substring(i + 1, i + 3), 16, "hexadecimal", str, i);
            builder.append(c);
            i += 2;
            break;
          case 'u':
            if (i + 5 > str.length()) {
              throw error("invalid unicode escape sequence", str, i);
            }
            c = parse(str.substring(i + 1, i + 5), 16, "unicode", str, i);
            builder.append(c);
            i += 4;
            break;
          default:
            builder.append('\\').append(c);
            break;
        }
      } else {
        builder.append(c);
      }
    }
    return builder.toString();
  }