Stack.jack

/**
 * Models the stack as a 2D array
 */

class Stack {
  field Array stack;

  constructor Stack new() {
    var int r;
    let stack = Array.new(Constants.LEVELS());
    let r = 0;

    while (r < Constants.LEVELS()) {
      let stack[r] = Array.new(Constants.COLS());
      let r = r + 1;
    }
    return this;
  }

  /** Adds a new row to the stack, keeping only blocks that are stackable */
  method int add(Array row, int level) {
    var int blocksStacked, i;
    var Array top, newTop;
    let top = stack[level - 1];
    let newTop = stack[level];
    let i = 0;
    let blocksStacked = 0;

    if (level = 0) {
      let newTop = stack[0];
      while (i < Constants.COLS()) {
        let newTop[i] = row[i];
        let i = i + 1;
      }
      let blocksStacked = 3;
    } else {
      while (i < Constants.COLS()) {
        let newTop[i] = top[i] & row[i];

        if (newTop[i]) {
          let blocksStacked = blocksStacked + 1;
        }
        let i = i + 1;
      }
    }
    return blocksStacked;
  }

  method Array getRow(int level) {
    return stack[level];
  }

  method void dispose() {
    do Memory.deAlloc(this);
    return;
  }
}