pragma solidity ^0.4.21;

contract ERC20 {
    
    function totalSupply() public view returns (uint256);
    function balanceOf(address _owner) public view returns (uint256);
    function transfer(address _to, uint256 _value) public returns (bool);
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool);
    function approve(address _spender, uint256 _value) public returns (bool);
    function allowance(address _owner, address _spender) public view returns (uint256);

    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);
}

contract Ownable {

    address public owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    function Ownable() {
        owner = msg.sender;
    }

    modifier onlyOwner() {
        require(msg.sender == owner);
        _;
    }

    function transferOwnership(address _newOwner) onlyOwner {
        require(_newOwner != address(0));
        OwnershipTransferred(owner, _newOwner);
        owner = _newOwner;
    }
}


contract Pausable is Ownable {
    
    event Pause();
    event Unpause();

    bool public paused = false;

    modifier whenNotPaused() {
        require(!paused);
        _;
    }

    modifier whenPaused() {
        require(paused);
        _;
    }

    function pause() onlyOwner whenNotPaused public {
        paused = true;
        Pause();
    }

    function unpause() onlyOwner whenPaused public {
        paused = false;
        Unpause();
    }
}

library SafeMath {
    /**
    * @dev Multiplies two numbers, throws on overflow.
    */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }
        uint256 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 c;
    }

    /**
    * @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) {
        uint256 c = a + b;
        assert(c >= a);
        return c;
    }
}

contract PCM is ERC20, Ownable, Pausable {
    using SafeMath for uint256;
    
    string public constant name     = "Precium Token";
    uint8 public constant decimals  = 18;
    string public constant symbol   = "PCM";

    mapping (address => uint256) public balances;
    mapping (address => mapping (address => uint256)) internal allowed;

    uint256 totalSupply_;

    function PCM(uint256 _amount) public Ownable() {
        totalSupply_ = _amount * 1 ether;
        balances[owner] = totalSupply_;
    }

    function totalSupply() public view returns (uint256) {
        return totalSupply_;
    }

    function balanceOf(address _owner) public view returns (uint256) {
        return balances[_owner];
    }

    function transfer(address _to, uint256 _value) public whenNotPaused 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);
        Transfer(msg.sender, _to, _value);

        return true;
    }

    function transferFrom(address _from, address _to, uint256 _value) public whenNotPaused 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);
        Transfer(_from, _to, _value);
        
        return true;
    }

    function approve(address _spender, uint256 _value) public whenNotPaused returns (bool) {
        allowed[msg.sender][_spender] = _value;
        Approval(msg.sender, _spender, _value);
        return true;
    }

    function allowance(address _owner, address _spender) public view returns (uint256) {
        return allowed[_owner][_spender];
    }

    function burn(uint256 _value) public onlyOwner {
        
        require(_value <= balances[msg.sender]);
    
        address burner = msg.sender;
        balances[burner] = balances[burner].sub(_value);
        totalSupply_ = totalSupply_.sub(_value);

        Transfer(burner, address(0), _value);
    }
}