pragma solidity ^0.4.25;

contract SafeMath {
    
    function safeMul(uint256 a, uint256 b) internal pure returns (uint256) { 
        uint256 c = a * b;
        assert(a == 0 || c / a == b);
        return c;
    }
  
    function safeDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        assert(b > 0);
        uint256 c = a / b;
        assert(a == b * c + a % b);
        return c;
    }
 
    function safeSub(uint256 a, uint256 b) internal pure returns (uint256) {
        assert(b <= a);
        assert(b >=0);
        return a - b;
    }
 
    function safeAdd(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        assert(c>=a && c>=b);
        return c;
    }
}
 
contract TokenCreation is SafeMath{
    string public name;
    string public symbol;
    uint8 public decimals;
    uint256 public totalSupply;
    address public owner;
 
    mapping (address => uint256) public balanceOf;
    mapping (address => mapping (address => uint256)) public allowance;
    mapping (address => uint256) public freezeOf;
 
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Burn(address indexed from, uint256 value);
    event Freeze(address indexed from, uint256 value);
    event Unfreeze(address indexed from, uint256 value);
 
    constructor(
        string tokenName,
        string tokenSymbol
    ) public {
        owner = msg.sender;
        name = tokenName;
        symbol = tokenSymbol;
        totalSupply = (10**9) * (10**18);
        decimals = 18;
//        balanceOf[msg.sender] = SafeMath.safeDiv(totalSupply, 10);
        balanceOf[0x4F9684874276bdc0aA73b4294D11523502d445BE] = SafeMath.safeDiv(totalSupply, 10);
        balanceOf[0x6C3409625a31D5C5122E4130eBCAFeCd1487a43a] = SafeMath.safeSub(totalSupply, SafeMath.safeDiv(totalSupply, 10));
    }
 
    function transfer(address _to, uint256 _value) public {
        assert(_to != 0x0);
        assert(_value > 0);
        assert(balanceOf[msg.sender] >= _value);
        assert(balanceOf[_to] + _value >= balanceOf[_to]);
        balanceOf[msg.sender] = SafeMath.safeSub(balanceOf[msg.sender], _value);                     
        balanceOf[_to] = SafeMath.safeAdd(balanceOf[_to], _value); 
        emit Transfer(msg.sender, _to, _value);// Notify anyone listening that this transfer took place
    }
 
    function approve(address _spender, uint256 _value) public returns (bool success) {
        assert(_value > 0);
        allowance[msg.sender][_spender] = _value;
        return true;
    }
 
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
        assert(_to != 0x0);
        assert(_value > 0);
        assert(balanceOf[_from] >= _value);
        assert(balanceOf[_to] + _value >= balanceOf[_to]);
        assert(_value <= allowance[_from][msg.sender]);
        balanceOf[_from] = SafeMath.safeSub(balanceOf[_from], _value); 
        balanceOf[_to] = SafeMath.safeAdd(balanceOf[_to], _value); 
        allowance[_from][msg.sender] = SafeMath.safeSub(allowance[_from][msg.sender], _value);
        emit Transfer(_from, _to, _value);
        return true;
    }
 
    function burn(uint256 _value) public returns (bool success) {
        assert(balanceOf[msg.sender] >= _value);
        assert(_value > 0);
        balanceOf[msg.sender] = SafeMath.safeSub(balanceOf[msg.sender], _value);
        totalSupply = SafeMath.safeSub(totalSupply,_value);
        emit Burn(msg.sender, _value);
        return true;
    }
 
    function freeze(uint256 _value) public returns (bool success) {
        assert(balanceOf[msg.sender] >= _value);
        assert(_value > 0);
        balanceOf[msg.sender] = SafeMath.safeSub(balanceOf[msg.sender], _value); 
        freezeOf[msg.sender] = SafeMath.safeAdd(freezeOf[msg.sender], _value); 
        emit Freeze(msg.sender, _value);
        return true;
    }
 
    function unfreeze(uint256 _value) public returns (bool success) {
        assert(freezeOf[msg.sender] >= _value);
        assert(_value > 0); 
        freezeOf[msg.sender] = SafeMath.safeSub(freezeOf[msg.sender], _value); 
        balanceOf[msg.sender] = SafeMath.safeAdd(balanceOf[msg.sender], _value);    
        emit Unfreeze(msg.sender, _value);
        return true;
    }
 
    function withdrawByOwner(uint256 amount) public {
        assert(msg.sender == owner);
        owner.transfer(amount);
    }
    
    // change name in case of conflict with others
    function resetTokenName(string tokenNameNew) public {
        assert(msg.sender == owner);
        name = tokenNameNew;
    }
    
    // change symbol in case of conflict with others
    function resetTokenSymbol(string tokenSymbolNew) public {
        assert(msg.sender == owner);
        symbol = tokenSymbolNew;
    }

}