Contract Source Code:
File 1 of 1 : WWWLToken
pragma solidity ^0.5.2;
/**
* @title SafeMath
* @dev Math operations with safety checks that revert on error
*/
library SafeMath {
/**
* @dev Multiplies two numbers, reverts on overflow.
*/
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
// Gas optimization: this is cheaper than requiring 'a' not being zero, but the
// benefit is lost if 'b' is also tested.
if (a == 0) {
return 0;
}
uint256 c = a * b;
require(c / a == b, "multiplication constraint voilated");
return c;
}
/**
* @dev Integer division of two numbers truncating the quotient, reverts on division by zero.
*/
function div(uint256 a, uint256 b) internal pure returns (uint256) {
// Solidity only automatically asserts when dividing by 0
require(b > 0, "division constraint voilated");
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, reverts on overflow (i.e. if subtrahend is greater than minuend).
*/
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
require(b <= a, "substracts constraint voilated");
uint256 c = a - b;
return c;
}
/**
* @dev Adds two numbers, reverts on overflow.
*/
function add(uint256 a, uint256 b) internal pure returns (uint256) {
uint256 c = a + b;
require(c >= a, "addition constraint voilated");
return c;
}
/**
* @dev Divides two numbers and returns the remainder (unsigned integer modulo),
* reverts when dividing by zero.
*/
function mod(uint256 a, uint256 b) internal pure returns (uint256) {
require(b != 0, "divides contraint voilated");
return a % b;
}
}
/**
* @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.
*/
constructor() public{
owner = msg.sender;
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
require(msg.sender == owner, "Ownable: only owner can execute");
_;
}
/**
* @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), "Ownable: new owner should not empty");
emit OwnershipTransferred(owner, newOwner);
owner = newOwner;
}
}
contract Pausable is Ownable {
event Pause();
event Unpause();
bool public paused = false;
/**
* @dev modifier to allow actions only when the contract IS paused
*/
modifier whenNotPaused() {
require(!paused, "Pausable: contract not paused");
_;
}
/**
* @dev modifier to allow actions only when the contract IS NOT paused
*/
modifier whenPaused {
require(paused, "Pausable: contract paused");
_;
}
/**
* @dev called by the owner to pause, triggers stopped state
*/
function pause() public onlyOwner whenNotPaused returns (bool) {
paused = true;
emit Pause();
return true;
}
/**
* @dev called by the owner to unpause, returns to normal state
*/
function unpause() public onlyOwner whenPaused returns (bool) {
paused = false;
emit Unpause();
return true;
}
}
/**
* @title ERC20Basic
* @dev Simpler version of ERC20 interface
* @dev see https://github.com/ethereum/EIPs/issues/179
*/
contract ERC20Basic {
uint256 public totalSupply;
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;
/**
* @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), "BasicToken: require to address");
// SafeMath.sub will throw if there is not enough balance.
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 balance) {
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);
}
/**
* @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 {
mapping (address => mapping (address => uint256)) 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 amount of tokens to be transferred
*/
function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
require(_to != address(0), "StandardToken: receiver address empty");
uint256 _allowance = allowed[_from][msg.sender];
// Check is not needed because sub(_allowance, _value) will already throw if this condition is not met
// require (_value <= _allowance);
balances[_from] = balances[_from].sub(_value);
balances[_to] = balances[_to].add(_value);
allowed[_from][msg.sender] = _allowance.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) {
require(_spender != address(0), "StandardToken: spender address empty");
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 remaining) {
return allowed[_owner][_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
*/
function increaseApproval (address _spender, uint256 _addedValue) public
returns (bool success) {
require(_spender != address(0), "StandardToken: spender address empty");
allowed[msg.sender][_spender] = allowed[msg.sender][_spender].add(_addedValue);
emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
return true;
}
function decreaseApproval (address _spender, uint256 _subtractedValue) public
returns (bool success) {
require(_spender != address(0), "StandardToken: spender address empty");
uint256 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;
}
}
contract MintableToken is StandardToken, Ownable {
event MintFinished();
bool public mintingFinished = false;
modifier canMint() {
require(!mintingFinished, "MintableToken: require minting active");
_;
}
/**
* @dev Function to mint tokens
* @param _to The address that will recieve the minted tokens.
* @param _value The amount of tokens to mint.
* @return A boolean that indicates if the operation was successful.
*/
function mint(address _to, uint256 _value) public onlyOwner canMint returns (bool) {
totalSupply = totalSupply.add(_value);
balances[_to] = balances[_to].add(_value);
emit Transfer(address(0), _to, _value);
return true;
}
/**
* @dev Function to stop minting new tokens.
* @return True if the operation was successful.
*/
function finishMinting() public onlyOwner returns (bool) {
mintingFinished = true;
emit MintFinished();
return true;
}
}
contract BurnableToken is StandardToken {
/**
* @dev Burns a specified amount of tokens.
* @param _value The amount of tokens to burn.
*/
function burn(uint256 _value) public {
require(_value > 0, "BurnableToken: value must be greterthan 0");
address burner = msg.sender;
balances[burner] = balances[burner].sub(_value);
totalSupply = totalSupply.sub(_value);
emit Transfer(msg.sender, address(0), _value);
}
}
contract PausableToken is StandardToken, Pausable {
function transfer(address _to, uint256 _value)public whenNotPaused returns (bool) {
return super.transfer(_to, _value);
}
function transferFrom(address _from, address _to, uint256 _value) public whenNotPaused returns (bool) {
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);
}
}
contract WWWLToken is MintableToken, PausableToken, BurnableToken {
string public name = "3WL";
string public symbol = "WWWL";
uint8 public decimals = 18;
uint256 public initialSupply = 100000000 * (10 ** uint256(decimals));
// Constructor
constructor() public {
totalSupply = initialSupply;
balances[msg.sender] = initialSupply; // Send all tokens to owner
emit Transfer(address(0), msg.sender, initialSupply);
}
// Don't accept ETH
function () external payable {
}
// Only owner can kill
function kill() public whenNotPaused onlyOwner {
selfdestruct(msg.sender);
}
}