// This is a port of sql/password.c:hash_password which needs to be used for
// pre-4.1 passwords.
exports.hashPassword = function(password) {
  var nr = 1345345333,
      add = 7,
      nr2 = 0x12345671,
      result = new Buffer(8);

  password = new Buffer(password);
  for (var i = 0; i < password.length; i++) {
    var c = password[i];
    if (c == 32 || c == 9) {
      // skip space in password
      continue;
    }

    nr ^= this.multiply(((nr & 63) + add), c) + (nr << 8);
    nr2 += (nr << 8) ^ nr;
    add += c;
  }

  this.int32Write(result, nr & ((1 << 31) - 1), 0);
  this.int32Write(result, nr2 & ((1 << 31) - 1), 4);

  return result;
}

exports.multiply = function(x, y) {
  var lowX = x & 0xffff,
      highX = (x >> 16) & 0xffff,
      lowY = y & 0xffff,
      highY = (y >> 16) & 0xffff
      result =
        0x10000 * ((highX * lowY + lowX * highY) & 0xffff) + lowY * lowX;

  //result = result & 0xffffffff;
  result = result % 0x100000000;
  return result;
}

exports.int32Write = function(buffer, number, offset) {
  var unsigned = (number < 0) ? (number + 0x100000000) : number;
  buffer[offset] = Math.floor(unsigned / 0xffffff);
  unsigned &= 0xffffff;
  buffer[offset + 1] = Math.floor(unsigned / 0xffff);
  unsigned &= 0xffff;
  buffer[offset + 2] = Math.floor(unsigned / 0xff);
  unsigned &= 0xff;
  buffer[offset + 3] = Math.floor(unsigned);
};