1 pragma solidity ^0.5.7;
  2 
  3 import \'./safemath.sol\';
  4 
  5 contract ErbCoin {
  6     using SafeMath for uint256;
  7 
  8     string constant public name = "Mask Coin";      //  token name
  9     string constant public symbol = "MASK";           //  token symbol
 10     uint256 public decimals = 18;            //  token digit
 11 
 12     //mapping (address => uint256) public balanceOf;
 13     mapping (address => mapping (address => uint256)) public allowance; //a授权给b表示b可转账给其他人的代币数
 14     mapping (address => uint256) public frozenBalances; //冻结余额
 15     mapping (address => uint256) public balances; //可操作余额
 16 
 17     uint256 public totalSupply = 0;
 18     bool public stopped = false;
 19 
 20     //uint256 constant valueFounder = 1000000;
 21     address constant zeroaddr = address(0);
 22     address owner = zeroaddr;   //合约所有者
 23     address founder = zeroaddr; //初始代币持有者
 24 
 25     modifier isOwner {
 26         assert(owner == msg.sender);
 27         _;
 28     }
 29 
 30     modifier isFounder {
 31         assert(founder == msg.sender);
 32         _;
 33     }
 34 
 35     modifier isAdmin {
 36         assert(owner == msg.sender || founder == msg.sender);
 37         _;
 38     }
 39 
 40     modifier isRunning {
 41         assert (!stopped);
 42         _;
 43     }
 44 
 45     modifier validAddress {
 46         assert(zeroaddr != msg.sender);
 47         _;
 48     }
 49 
 50     constructor(address _addressFounder,uint256 _valueFounder) public {
 51         owner = msg.sender;
 52         founder = _addressFounder;
 53         totalSupply = _valueFounder*10**decimals;
 54         balances[founder] = totalSupply;
 55         emit Transfer(zeroaddr, founder, totalSupply);
 56     }
 57 
 58     function balanceOf(address _owner) public view returns (uint256) {
 59         //账户余额 = 可操作余额 + 被冻结余额
 60         return balances[_owner] + frozenBalances[_owner];
 61     }
 62 
 63     function transfer(address _to, uint256 _value) public isRunning validAddress returns (bool success) {
 64         balances[msg.sender] = balances[msg.sender].sub(_value);
 65         balances[_to] = balances[_to].add(_value);
 66         emit Transfer(msg.sender, _to, _value);
 67         return true;
 68     }
 69 
 70     //msg.sender 将 _from 授权给他（msg.sender）的代币转给 _to
 71     function transferFrom(address _from, address _to, uint256 _value) public isRunning validAddress returns (bool success) {
 72         balances[_from] = balances[_from].sub(_value);
 73         //balances[_to] = balances[_to].add(_value);
 74         frozenBalances[_to] = frozenBalances[_to].add(_value); //代币为冻结状态
 75         allowance[_from][msg.sender] = allowance[_from][msg.sender].sub(_value);
 76         emit TransferFrozen(_to, _value);
 77         return true;
 78     }
 79 
 80     //msg.sender 授权 _spender 可操作代币数
 81     function approve(address _spender, uint256 _value) public isRunning isFounder returns (bool success) {
 82         require(_value == 0 || allowance[msg.sender][_spender] == 0,"illegal operation");
 83         allowance[msg.sender][_spender] = _value;
 84         emit Approval(msg.sender, _spender, _value);
 85         return true;
 86     }
 87 
 88     //冻结部分释放
 89     function release(address _target, uint256 _value) public isRunning isAdmin returns(bool){
 90         frozenBalances[_target] = frozenBalances[_target].sub(_value);
 91         balances[_target] = balances[_target].add(_value);
 92         emit Release(_target, _value);
 93         return true;
 94     }
 95 
 96     function stop() public isAdmin {
 97         stopped = true;
 98     }
 99 
100     function start() public isAdmin {
101         stopped = false;
102     }
103 
104     event Transfer(address indexed _from, address indexed _to, uint256 _value);
105     event Approval(address indexed _owner, address indexed _spender, uint256 _value);
106     event TransferFrozen(address _target, uint256 _value);
107     event Release(address _target, uint256 _value);
108 }