pragma solidity 0.4.21;
/**
 * @title SafeMath
 * @dev Math operations with safety checks that throw on error
 */
library SafeMath {

  /**
  * @dev Multiplies two numbers, throws on overflow.
  */
    function mul(uint256 a, uint256 b) internal pure returns (uint256 c) 
    {
        if (a == 0) 
        {
            return 0;
        }
        c = a * b;
        assert(c / a == b);
        return c;
    }

  /**
  * @dev Integer division of two numbers, truncating the quotient.
  */
    function div(uint256 a, uint256 b) internal pure returns (uint256) 
    {
    // assert(b > 0); // Solidity automatically throws when dividing by 0
    // uint256 c = a / b;
    // assert(a == b * c + a % b); // There is no case in which this doesn't hold
        return a / b;
    }

  /**
  * @dev Subtracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
  */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) 
    {
        assert(b <= a);
        return a - b;
    }

  /**
  * @dev Adds two numbers, throws on overflow.
  */
    function add(uint256 a, uint256 b) internal pure returns (uint256 c) 
    {
        c = a + b;
        assert(c >= a);
        return c;
    }
}

 /**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
contract Ownable {
    address public owner;


    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

  /**
   * @dev The Ownable constructor sets the original `owner` of the contract to the sender
   * account.
   */

    function Ownable() public {
        owner = msg.sender;
    }

  /**
   * @dev Throws if called by any account other than the owner.
   */
    modifier onlyOwner() {
        require(msg.sender == owner);
        _;
    }

  /**
   * @dev Allows the current owner to transfer control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
    function transferOwnership(address newOwner) public onlyOwner {
        require(newOwner != address(0));
        emit OwnershipTransferred(owner, newOwner);
        owner = newOwner;
    }

}

/**
 * @title Pausable
 * @dev Base contract which allows children to implement an emergency stop mechanism.
 */
contract Pausable is Ownable {
    event Pause();
    event Unpause();

    bool public paused = false;

  /**
   * @dev Modifier to make a function callable only when the contract is not paused.
   */
    modifier whenNotPaused() {
        require(!paused);
        _;
    }

  /**
   * @dev Modifier to make a function callable only when the contract is paused.
   */
    modifier whenPaused() {
        require(paused);
        _;
    }

  /**
   * @dev called by the owner to pause, triggers stopped state
   */
    function pause() onlyOwner whenNotPaused public {
        paused = true;
        emit Pause();
    }

  /**
   * @dev called by the owner to unpause, returns to normal state
   */
    function unpause() onlyOwner whenPaused public {
        paused = false;
        emit Unpause();
    }
}

contract ERC20Basic {
    function totalSupply() public view returns (uint256);
    function balanceOf(address who) public view returns (uint256);
    function transfer(address to, uint256 value) public returns (bool);
    event Transfer(address indexed from, address indexed to, uint256 value);
}

/**
 * @title Basic token
 * @dev Basic version of StandardToken, with no allowances.
 */
contract BasicToken is ERC20Basic {
    using SafeMath for uint256;

    mapping(address => uint256) balances;
    string public name;
    string public symbol;
    uint8 public decimals = 18;
    uint256 totalSupply_;

  /**
  * @dev total number of tokens in existence
  */
    function totalSupply() public view returns (uint256) {
        return totalSupply_;
    }

  /**
  * @dev transfer token for a specified address
  * @param _to The address to transfer to.
  * @param _value The amount to be transferred.
  */
    function transfer(address _to, uint256 _value) public returns (bool) {
        require(_to != address(0));
        require(_value <= balances[msg.sender]);

        balances[msg.sender] = balances[msg.sender].sub(_value);
        balances[_to] = balances[_to].add(_value);
        emit Transfer(msg.sender, _to, _value);
        return true;
    }

  /**
  * @dev Gets the balance of the specified address.
  * @param _owner The address to query the the balance of.
  * @return An uint256 representing the amount owned by the passed address.
  */
    function balanceOf(address _owner) public view returns (uint256) 
    {
        return balances[_owner];
    }

}

// @title ERC20 interface
// @dev see https://github.com/ethereum/EIPs/issues/20
contract ERC20 is ERC20Basic {
    function allowance(address owner, address spender) public view returns (uint256);
    function transferFrom(address from, address to, uint256 value) public returns (bool);
    function approve(address spender, uint256 value) public returns (bool);
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

contract BurnableToken is BasicToken {
    event Burn(address indexed burner, uint256 value);

  /**
   * @dev Burns a specific amount of tokens.
   * @param _value The amount of token to be burned.
   */
    function burn(uint256 _value) public {
        _burn(msg.sender, _value);
    }

    function _burn(address _who, uint256 _value) internal {
        require(_value <= balances[_who]);  
    // no need to require value <= totalSupply, since that would imply the
    // sender's balance is greater than the totalSupply, which *should* be an assertion failure
        balances[_who] = balances[_who].sub(_value);
        totalSupply_ = totalSupply_.sub(_value);
        emit Burn(_who, _value);
        emit Transfer(_who, address(0), _value);
    }
}

//@title Standard ERC20 token
//@dev Implementation of the basic standard token.
//@dev https://github.com/ethereum/EIPs/issues/20
//@dev Based on code by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
contract StandardToken is ERC20, BasicToken,Ownable{

    mapping (address => mapping (address => uint256)) internal allowed;

  /**
   * @dev Transfer tokens from one address to another
   * @param _from address The address which you want to send tokens from
   * @param _to address The address which you want to transfer to
   * @param _value uint256 the amout of tokens to be transfered
   */
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
        require(_to != address(0));
        require(_value <= balances[_from]);
        require(_value <= allowed[_from][msg.sender]);

        balances[_from] = balances[_from].sub(_value);
        balances[_to] = balances[_to].add(_value);
        allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
        emit Transfer(_from, _to, _value);
        return true;
    }

  /**
   * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
   *
   * Beware that changing an allowance with this method brings the risk that someone may use both the old
   * and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this
   * race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards:
   * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
   * @param _spender The address which will spend the funds.
   * @param _value The amount of tokens to be spent.
   */
    function approve(address _spender, uint256 _value) public returns (bool) {
        allowed[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        return true;
    }

  /**
   * @dev Function to check the amount of tokens that an owner allowed to a spender.
   * @param _owner address The address which owns the funds.
   * @param _spender address The address which will spend the funds.
   * @return A uint256 specifying the amount of tokens still available for the spender.
   */
    function allowance(address _owner, address _spender) public view returns (uint256) {
        return allowed[_owner][_spender];
    }

  /**
   * @dev Increase the amount of tokens that an owner allowed to a spender.
   *
   * approve should be called when allowed[_spender] == 0. To increment
   * allowed value is better to use this function to avoid 2 calls (and wait until
   * the first transaction is mined)
   * From MonolithDAO Token.sol
   * @param _spender The address which will spend the funds.
   * @param _addedValue The amount of tokens to increase the allowance by.
   */
    function increaseApproval(address _spender, uint _addedValue) public returns (bool) {
        allowed[msg.sender][_spender] = allowed[msg.sender][_spender].add(_addedValue);
        emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
        return true;
    }

  /**
   * @dev Decrease the amount of tokens that an owner allowed to a spender.
   *
   * approve should be called when allowed[_spender] == 0. To decrement
   * allowed value is better to use this function to avoid 2 calls (and wait until
   * the first transaction is mined)
   * From MonolithDAO Token.sol
   * @param _spender The address which will spend the funds.
   * @param _subtractedValue The amount of tokens to decrease the allowance by.
   */
    function decreaseApproval(address _spender, uint _subtractedValue) public returns (bool) {
        uint oldValue = allowed[msg.sender][_spender];
        if (_subtractedValue > oldValue) 
        {
            allowed[msg.sender][_spender] = 0;
        } else {
            allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue);
        }
        emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
        return true;
    }

}

/* ABE Token */
contract ABEToken is BurnableToken, StandardToken,Pausable {
    /* This generates a public event on the blockchain that will notify clients */
    /*It will invoke a public event in block chain, and inform client*/
    mapping (address => bool) public frozenAccount;
    event FrozenFunds(address target, bool frozen);
    function ABEToken() public 
    {
        totalSupply_ = 10000000000 ether;//Total amount of tokens
        balances[msg.sender] = totalSupply_;               //Initial tokens for owner
        name = "ABE";             //for display
        symbol = "ABE";                               //Symbol for display
    }


 /**
  * @dev Burns a specific amount of tokens from the target address and decrements allowance
 * @param _from address The address which you want to send tokens from
  * @param _value uint256 The amount of token to be burned
 */
    function burnFrom(address _from, uint256 _value) public {
        require(_value <= allowed[_from][msg.sender]);
		// Should https://github.com/OpenZeppelin/zeppelin-solidity/issues/707 be accepted,
		// this function needs to emit an event with the updated approval.
        allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
        _burn(_from, _value);
    }
    //Freeze an account (Owner only).
    function freezeAccount(address target, bool freeze) onlyOwner public {
        frozenAccount[target] = freeze;
        emit FrozenFunds(target, freeze);
    }
    function transfer(address _to, uint256 _value) public whenNotPaused returns (bool) {
        require(!frozenAccount[msg.sender]);               //Check if the sender is frozen.
        return super.transfer(_to, _value);
    }
    //Send tokens to an account and froze the account immediately (Owner only).
    function transferAndFrozen(address _to, uint256 _value) onlyOwner public whenNotPaused returns (bool) {
        require(!frozenAccount[msg.sender]);               //Check if the sender is frozen.
        bool Result = transfer(_to,_value);
        freezeAccount(_to,true);
        return Result;
    }
    function transferFrom(address _from, address _to, uint256 _value) public whenNotPaused returns (bool) {
        require(!frozenAccount[_from]);                     //Check if the sender is frozen.
        return super.transferFrom(_from, _to, _value);
    }

    function approve(address _spender, uint256 _value) public whenNotPaused returns (bool) {
        return super.approve(_spender, _value);
    }

    function increaseApproval(address _spender, uint _addedValue) public whenNotPaused returns (bool success) {
        return super.increaseApproval(_spender, _addedValue);
    }

    function decreaseApproval(address _spender, uint _subtractedValue) public whenNotPaused returns (bool success) {
        return super.decreaseApproval(_spender, _subtractedValue);
    }
}