/**
* @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) {
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 owned {
address public owner;
constructor() public {
owner = msg.sender;
}
modifier onlyOwner {
require(msg.sender == owner);
_;
}
function transferOwnership(address _newOwner) onlyOwner public {
owner = _newOwner;
}
}
contract GOG is owned {
using SafeMath for uint256;
// Public variables of the GOG token
string public name;
string public symbol;
uint8 public decimals = 6;
// 6 decimals for GOG
uint256 public totalSupply;
bool public paused;
// This creates an array with all balances
mapping (address => uint256) public balances;
// this creates an 2 x 2 array with allowances
mapping (address => mapping (address => uint256)) public allowance;
// This generates a public event on the blockchain that will notify clients transfering of funds
event Transfer(address indexed from, address indexed to, uint256 value);
// This notifies clients about the amount burnt
event Burn(address indexed from, uint256 value);
// This notifies clients about approval of allowances
event Approval(address indexed owner, address indexed spender, uint256 value);
event Pause(address indexed owner);
event Unpause(address indexed owner);
modifier onlyUnpaused() {
require(!paused);
_;
}
/**
* Constrctor function
* Initializes contract with initial supply tokens to the creator of the contract
*/
constructor() public {
totalSupply = 10000000000000000; // GOG's total supply is 10 billion with 6 decimals
balances[msg.sender] = totalSupply; // Give the creator all initial tokens
name = "GoGlobe Token"; // Token name is GoGlobe Token
symbol = "GOG"; // token symbol is GOG
}
/**
* get the balance of account
* @param _owner The account address
*/
function balanceOf(address _owner) view public returns (uint256) {
return balances[_owner];
}
/**
* @dev Aprove the passed address to spend the specified amount of tokens on behalf of msg.sender.
* @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 onlyUnpaused returns (bool) {
require((_value == 0) || (allowance[msg.sender][_spender] == 0));
allowance[msg.sender][_spender] = _value;
emit Approval(msg.sender, _spender, _value);
return true;
}
/**
* @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 onlyUnpaused returns (bool) {
allowance[msg.sender][_spender] = allowance[msg.sender][_spender].add(_addedValue);
emit Approval(msg.sender, _spender, allowance[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 onlyUnpaused returns (bool) {
uint oldValue = allowance[msg.sender][_spender];
if (_subtractedValue > oldValue) {
allowance[msg.sender][_spender] = 0;
} else {
allowance[msg.sender][_spender] = oldValue.sub(_subtractedValue);
}
emit Approval(msg.sender, _spender, allowance[msg.sender][_spender]);
return true;
}
/**
* @dev Function to check the amount of tokens that an owner allowance 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 specifing the amount of tokens still avaible for the spender.
*/
function allowance(address _owner, address _spender) view public returns (uint256) {
return allowance[_owner][_spender];
}
/**
* Internal transfer, only can be called by this contract
*/
function _transfer(address _from, address _to, uint _value) internal {
// Prevent transfer to 0x0 address. Use burn() instead
require(_to != address(0));
// Check if the sender has enough
require(balances[_from] >= _value);
// Save this for an assertion in the future
uint previousBalances = balances[_from].add(balances[_to]);
// Subtract from the sender
balances[_from] = balances[_from].sub(_value);
// Add the same to the recipient
balances[_to] = balances[_to].add(_value);
emit Transfer(_from, _to, _value);
// Asserts are used to use static analysis to find bugs in your code. They should never fail
assert(balances[_from] + balances[_to] == previousBalances);
}
/**
* Transfer tokens
* Send `_value` tokens to `_to` from your account
* @param _to The address of the recipient
* @param _value the amount to send
*/
function transfer(address _to, uint256 _value) public onlyUnpaused {
_transfer(msg.sender, _to, _value);
}
/**
* Transfer tokens from other address
* Send `_value` tokens to `_to` on behalf of `_from`
* @param _from The address of the sender
* @param _to The address of the recipient
* @param _value the amount to send
*/
function transferFrom(address _from, address _to, uint256 _value) public onlyUnpaused returns (bool) {
require(_value <= allowance[_from][msg.sender]); // Check allowance
allowance[_from][msg.sender] = allowance[_from][msg.sender].sub(_value);
_transfer(_from, _to, _value);
return true;
}
/**
* Destroy tokens
* Remove `_value` tokens from the system irreversibly
* @param _value the amount of money to burn
*/
function burn(uint256 _value) public onlyUnpaused returns (bool) {
require(balances[msg.sender] >= _value); // Check if the sender has enough
balances[msg.sender] = balances[msg.sender].sub(_value); // Subtract from the sender
totalSupply = totalSupply.sub(_value); // Updates totalSupply
emit Burn(msg.sender, _value);
return true;
}
/**
* Destroy tokens from other account
* Remove `_value` tokens from the system irreversibly on behalf of `_from`.
* @param _from the address of the sender
* @param _value the amount of money to burn
*/
function burnFrom(address _from, uint256 _value) public onlyUnpaused returns (bool) {
require(balances[_from] >= _value); // Check if the targeted balance is enough
require(_value <= allowance[_from][msg.sender]); // Check allowance
balances[_from] = balances[_from].sub(_value); // Subtract from the targeted balance
allowance[_from][msg.sender] = allowance[_from][msg.sender].sub(_value); // Subtract from the sender's allowance
totalSupply = totalSupply.sub(_value); // Update totalSupply
emit Burn(_from, _value);
return true;
}
function pause() public onlyOwner returns (bool) {
paused = true;
return true;
}
function unPause() public onlyOwner returns (bool) {
paused = false;
return true;
}
}
{
"compilationTarget": {
"GOG.sol": "GOG"
},
"evmVersion": "byzantium",
"libraries": {},
"optimizer": {
"enabled": false,
"runs": 0
},
"remappings": []
}
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