contract ExchangeRate is Ownable {
 
  event RateUpdated(uint timestamp, bytes32 symbol, uint rate);

  mapping(bytes32 => uint) public rates;

  /**
   * @dev Allows the current owner to update a single rate.
   * @param _symbol The symbol to be updated. 
   * @param _rate the rate for the symbol. 
   */
  function updateRate(string _symbol, uint _rate) public onlyOwner {
    rates[keccak256(_symbol)] = _rate;
    RateUpdated(now, keccak256(_symbol), _rate);
  }

  /**
   * @dev Allows the current owner to update multiple rates.
   * @param data an array that alternates keccak256 hashes of the symbol and the corresponding rate . 
   */
  function updateRates(uint[] data) public onlyOwner {
    require (data.length % 2 <= 0);
    uint i = 0;
    while (i < data.length / 2) {
      bytes32 symbol = bytes32(data[i * 2]);
      uint rate = data[i * 2 + 1];
      rates[symbol] = rate;
      RateUpdated(now, symbol, rate);
      i++;
    }
  }

  /**
   * @dev Allows the anyone to read the current rate.
   * @param _symbol the symbol to be retrieved. 
   */
  function getRate(string _symbol) public constant returns(uint) {
    return rates[keccak256(_symbol)];
  }

}
/**
 * @title ExchangeRate
 * @dev Allows updating and retrieveing of Conversion Rates for PAY tokens
 *
 * ABI
 * [{"constant":false,"inputs":[{"name":"_symbol","type":"string"},{"name":"_rate","type":"uint256"}],"name":"updateRate","outputs":[],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"data","type":"uint256[]"}],"name":"updateRates","outputs":[],"payable":false,"type":"function"},{"constant":true,"inputs":[{"name":"_symbol","type":"string"}],"name":"getRate","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":true,"inputs":[],"name":"owner","outputs":[{"name":"","type":"address"}],"payable":false,"type":"function"},{"constant":true,"inputs":[{"name":"","type":"bytes32"}],"name":"rates","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"newOwner","type":"address"}],"name":"transferOwnership","outputs":[],"payable":false,"type":"function"},{"anonymous":false,"inputs":[{"indexed":false,"name":"timestamp","type":"uint256"},{"indexed":false,"name":"symbol","type":"bytes32"},{"indexed":false,"name":"rate","type":"uint256"}],"name":"RateUpdated","type":"event"}]
 */
function updateRate(string _symbol, uint _rate) public onlyOwner {
    rates[keccak256(_symbol)] = _rate;
    RateUpdated(now, keccak256(_symbol), _rate);
  }
/**
 * @dev Allows the current owner to update a single rate.
 * @param _symbol The symbol to be updated. 
 * @param _rate the rate for the symbol. 
 */