engine.js

  this.tryHash = function(midstate, half, data, hash1, target, nonce){  
    data[3] = nonce;
    this.sha.reset();

    var h0 = this.sha.update(midstate, data).state;   // compute first hash
    for (var i = 0; i < 8; i++) hash1[i] = h0[i];   // place it in the h1 holder
    this.sha.reset();                 // reset to initial state
    var h = this.sha.update(hash1).state;       // compute final hash
    if (h[7] == 0) {
      var ret = [];
      for (var i = 0; i < half.length; i++)
        ret.push(half[i]);
      for (var i = 0; i < data.length; i++)
        ret.push(data[i]);
      return ret;
    } else return null;
};