pragma solidity 0.4.20;


import 'libraries/token/StandardToken.sol';


contract VariableSupplyToken is StandardToken {
    using SafeMathUint256 for uint256;

    event Mint(address indexed target, uint256 value);
    event Burn(address indexed target, uint256 value);

    /**
    * @dev mint tokens for a specified address
    * @param _target The address to mint tokens for.
    * @param _amount The amount to be minted.
    */
    function mint(address _target, uint256 _amount) internal returns (bool) {
        balances[_target] = balances[_target].add(_amount);
        supply = supply.add(_amount);
        Mint(_target, _amount);
        onMint(_target, _amount);
        return true;
    }

    /**
    * @dev burn tokens belonging to a specified address
    * @param _target The address to burn tokens for.
    * @param _amount The amount to be burned.
    */
    function burn(address _target, uint256 _amount) internal returns (bool) {
        balances[_target] = balances[_target].sub(_amount);
        supply = supply.sub(_amount);
        Burn(_target, _amount);
        onBurn(_target, _amount);
        return true;
    }

    // Subclasses of this token may want to send additional logs through the centralized Augur log emitter contract
    function onMint(address, uint256) internal returns (bool);

    // Subclasses of this token may want to send additional logs through the centralized Augur log emitter contract
    function onBurn(address, uint256) internal returns (bool);
}