// supports 8 different character classes
sclass JSONSpecialIntegral {
  int minLevel = 1, maxLevel = 8;

  byte[] input;
  
  int[] bracketLevel;
  byte[] quotesBitSet; // faster replacement for BitSet
  
  *() {}
  *(byte[] *input) {}

  void analyze(S input) {
    this.input = toUtf8(input); // XXX probably wrong
    analyze();
  }
  
  void analyze(byte[] input) {
    this.input = input;
    analyze();
  }
  
  void analyze {
    byte[] input = this.input;
    int n = input.length;
    bracketLevel = new int[n];
    quotesBitSet = byteArrayBitSet_new(n);

    int bracketLvl = 0;
    bool inQuotes;

    for i to n: {
      byte b = input[i];
      if (isOpener(b)) { if (!inQuotes) ++bracketLvl; }
      else if (isCloser(b)) { if (!inQuotes) --bracketLvl; }
      else if (b == '\'') {
        // TODO if (inQuotes) ...
      } else if (b == '"') {
        inQuotes = !inQuotes;
      }
      bracketLevel[i] = bracketLvl;
      setBit(quotesBitSet, i, inQuotes);
    }
  }
  
  int bracketLevel(int idx) {
    ret bracketLevel[rclamp(0, bracketLevel.length, idx)];
  }
  
  bool inQuoteBit(int idx) {
    ret getBit(quotesBitSet, idx);
  }
  
  bool isOpener(byte b) {
    ret b == '{' || b == '[';
  }
  
  bool isCloser(byte b) {
    ret b == '}' || b == ']';
  }
  
  S stats() {
    ret renderVars(
      inputLength := l(input),
      sizeFactor := formatDouble(elementSize(bracketLevel)+1/8.0), 2);
  }
  
  int n() { ret input.length; }
}