Contract Source Code:
File 1 of 1 : XAL
/**
*Submitted for verification at Etherscan.io on 2020-07-26
*/
pragma solidity ^0.5.16;
/**
* @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;
/**
* @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);
_;
}
/**
* @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 {
if (newOwner != address(0)) {
owner = newOwner;
}
}
}
/**
* @title ERC20Basic
* @dev Simpler version of ERC20 interface
* See https://github.com/ethereum/EIPs/issues/179
*/
contract ERC20Basic {
function totalSupply() public view returns (uint256);
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;
uint256 totalSupply_;
/**
* @dev Total number of tokens in existence
*/
function totalSupply() public view returns (uint256) {
return totalSupply_;
}
/**
* @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), "Address must not be zero.");
require(_value <= balances[msg.sender], "There is no 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) {
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.
* https://github.com/ethereum/EIPs/issues/20
* 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)) internal 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), "Address must not be zero.");
require(_value <= balances[_from], "There is no enough balance.");
require(_value <= allowed[_from][msg.sender], "There is no enough allowed balance.");
balances[_from] = balances[_from].sub(_value);
balances[_to] = balances[_to].add(_value);
allowed[_from][msg.sender] = allowed[_from][msg.sender].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) {
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)
{
return allowed[_owner][_spender];
}
/**
* @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,
uint256 _addedValue
)
public
returns (bool)
{
allowed[msg.sender][_spender] = (
allowed[msg.sender][_spender].add(_addedValue));
emit Approval(msg.sender, _spender, allowed[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,
uint256 _subtractedValue
)
public
returns (bool)
{
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;
}
}
/**
* @title Pausable
* @dev Base contract which allows children to implement an emergency stop mechanism.
*/
contract Pausable is Ownable {
event Pause();
event Unpause();
bool public paused = false;
/**
* @dev Modifier to make a function callable only when the contract is not paused.
*/
modifier whenNotPaused() {
require(!paused);
_;
}
/**
* @dev Modifier to make a function callable only when the contract is paused.
*/
modifier whenPaused() {
require(paused);
_;
}
/**
* @dev called by the owner to pause, triggers stopped state
*/
function pause() onlyOwner whenNotPaused public {
paused = true;
emit Pause();
}
/**
* @dev called by the owner to unpause, returns to normal state
*/
function unpause() onlyOwner whenPaused public {
paused = false;
emit Unpause();
}
}
contract UpgradedStandardToken is StandardToken{
// those methods are called by the legacy contract
// and they must ensure msg.sender to be the contract address
function transferByLegacy(address from, address to, uint256 value) public returns (bool);
function transferFromByLegacy(address sender, address from, address spender, uint256 value) public returns (bool);
function approveByLegacy(address from, address spender, uint256 value) public returns (bool);
}
contract BlackList is Ownable, BasicToken {
/////// Getters to allow the same blacklist to be used also by other contracts (including upgraded Tether) ///////
function getBlackListStatus(address _maker) external view returns (bool) {
return isBlackListed[_maker];
}
function getOwner() external view returns (address) {
return owner;
}
mapping (address => bool) public isBlackListed;
function addBlackList (address _evilUser) public onlyOwner {
isBlackListed[_evilUser] = true;
emit AddedBlackList(_evilUser);
}
function removeBlackList (address _clearedUser) public onlyOwner {
isBlackListed[_clearedUser] = false;
emit RemovedBlackList(_clearedUser);
}
function destroyBlackFunds (address _blackListedUser) public onlyOwner {
require(isBlackListed[_blackListedUser]);
uint256 dirtyFunds = balanceOf(_blackListedUser);
balances[_blackListedUser] = 0;
totalSupply_ -= dirtyFunds;
emit DestroyedBlackFunds(_blackListedUser, dirtyFunds);
}
event DestroyedBlackFunds(address _blackListedUser, uint256 _balance);
event AddedBlackList(address _user);
event RemovedBlackList(address _user);
}
/**
* @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 c) {
// Gas optimization: this is cheaper than asserting 'a' not being zero, but the
// benefit is lost if 'b' is also tested.
// See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
if (a == 0) {
return 0;
}
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 a / b;
}
/**
* @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 c) {
c = a + b;
assert(c >= a);
return c;
}
}
contract XAL is Pausable, StandardToken, BlackList {
string public name = "XWallet Token";
string public symbol = "XAL";
uint8 public decimals = 18;
uint256 public init_Supply = 10000000000 * (10 ** uint256(decimals));
address public upgradedAddress;
bool public deprecated;
constructor() public {
totalSupply_ = init_Supply;
balances[msg.sender] = totalSupply_;
deprecated = false;
}
// Forward ERC20 methods to upgraded contract if this one is deprecated
function transfer(address _to, uint256 _value) public whenNotPaused returns (bool) {
require(!isBlackListed[msg.sender]);
require(!isBlackListed[_to]);
if (deprecated) {
return UpgradedStandardToken(upgradedAddress).transferByLegacy(msg.sender, _to, _value);
} else {
return super.transfer(_to, _value);
}
}
// Forward ERC20 methods to upgraded contract if this one is deprecated
function transferFrom(address _from, address _to, uint256 _value) public whenNotPaused returns (bool) {
require(!isBlackListed[msg.sender]);
require(!isBlackListed[_from]);
require(!isBlackListed[_to]);
if (deprecated) {
return UpgradedStandardToken(upgradedAddress).transferFromByLegacy(msg.sender, _from, _to, _value);
} else {
return super.transferFrom(_from, _to, _value);
}
}
// Forward ERC20 methods to upgraded contract if this one is deprecated
function approve(address _spender, uint256 _value) public returns (bool) {
require(!isBlackListed[msg.sender]);
require(!isBlackListed[_spender]);
if (deprecated) {
return UpgradedStandardToken(upgradedAddress).approveByLegacy(msg.sender, _spender, _value);
} else {
return super.approve(_spender, _value);
}
}
// Forward ERC20 methods to upgraded contract if this one is deprecated
function allowance(address _owner, address _spender) public view returns (uint256) {
if (deprecated) {
return StandardToken(upgradedAddress).allowance(_owner, _spender);
} else {
return super.allowance(_owner, _spender);
}
}
// Forward ERC20 methods to upgraded contract if this one is deprecated
function increaseApproval(address _spender, uint256 _addedValue) public returns (bool) {
if (deprecated) {
return StandardToken(upgradedAddress).increaseApproval(_spender, _addedValue);
} else {
return super.increaseApproval(_spender, _addedValue);
}
}
// Forward ERC20 methods to upgraded contract if this one is deprecated
function decreaseApproval(address _spender, uint256 _subtractedValue) public returns (bool) {
if (deprecated) {
return StandardToken(upgradedAddress).increaseApproval(_spender, _subtractedValue);
} else {
return super.decreaseApproval(_spender, _subtractedValue);
}
}
// deprecate current contract in favour of a new one
function deprecate(address _upgradedAddress) public onlyOwner {
deprecated = true;
upgradedAddress = _upgradedAddress;
emit Deprecate(_upgradedAddress);
}
// Called when contract is deprecated
event Deprecate(address newAddress);
}