文件 1 的 1:AXSToken.sol
pragma solidity 0.5.17;
library SafeMath {
function add(uint256 a, uint256 b) internal pure returns (uint256 c) {
c = a + b;
require(c >= a, "SafeMath: addition overflow");
}
function sub(uint256 a, uint256 b) internal pure returns (uint256 c) {
require(b <= a, "SafeMath: subtraction overflow");
return a - b;
}
function mul(uint256 a, uint256 b) internal pure returns (uint256 c) {
if (a == 0) {
return 0;
}
c = a * b;
require(c / a == b, "SafeMath: multiplication overflow");
}
function div(uint256 a, uint256 b) internal pure returns (uint256 c) {
require(b > 0, "SafeMath: division by zero");
return a / b;
}
function mod(uint256 a, uint256 b) internal pure returns (uint256 c) {
require(b > 0, "SafeMath: modulo by zero");
return a % b;
}
}
pragma solidity 0.5.17;
interface IERC20 {
event Transfer(address indexed _from, address indexed _to, uint256 _value);
event Approval(address indexed _owner, address indexed _spender, uint256 _value);
function totalSupply() external view returns (uint256 _supply);
function balanceOf(address _owner) external view returns (uint256 _balance);
function approve(address _spender, uint256 _value) external returns (bool _success);
function allowance(address _owner, address _spender) external view returns (uint256 _value);
function transfer(address _to, uint256 _value) external returns (bool _success);
function transferFrom(address _from, address _to, uint256 _value) external returns (bool _success);
}
pragma solidity 0.5.17;
contract ERC20 is IERC20 {
using SafeMath for uint256;
uint256 public totalSupply;
mapping (address => uint256) public balanceOf;
mapping (address => mapping (address => uint256)) internal _allowance;
function approve(address _spender, uint256 _value) public returns (bool) {
_approve(msg.sender, _spender, _value);
return true;
}
function allowance(address _owner, address _spender) public view returns (uint256) {
return _allowance[_owner][_spender];
}
function increaseAllowance(address _spender, uint256 _value) public returns (bool) {
_approve(msg.sender, _spender, _allowance[msg.sender][_spender].add(_value));
return true;
}
function decreaseAllowance(address _spender, uint256 _value) public returns (bool) {
_approve(msg.sender, _spender, _allowance[msg.sender][_spender].sub(_value));
return true;
}
function transfer(address _to, uint256 _value) public returns (bool _success) {
_transfer(msg.sender, _to, _value);
return true;
}
function transferFrom(address _from, address _to, uint256 _value) public returns (bool _success) {
_transfer(_from, _to, _value);
_approve(_from, msg.sender, _allowance[_from][msg.sender].sub(_value));
return true;
}
function _approve(address _owner, address _spender, uint256 _amount) internal {
require(_owner != address(0), "ERC20: approve from the zero address");
require(_spender != address(0), "ERC20: approve to the zero address");
_allowance[_owner][_spender] = _amount;
emit Approval(_owner, _spender, _amount);
}
function _transfer(address _from, address _to, uint256 _value) internal {
require(_from != address(0), "ERC20: transfer from the zero address");
require(_to != address(0), "ERC20: transfer to the zero address");
require(_to != address(this), "ERC20: transfer to this contract address");
balanceOf[_from] = balanceOf[_from].sub(_value);
balanceOf[_to] = balanceOf[_to].add(_value);
emit Transfer(_from, _to, _value);
}
}
pragma solidity 0.5.17;
interface IERC20Detailed {
function name() external view returns (string memory _name);
function symbol() external view returns (string memory _symbol);
function decimals() external view returns (uint8 _decimals);
}
pragma solidity 0.5.17;
contract ERC20Detailed is ERC20, IERC20Detailed {
string public name;
string public symbol;
uint8 public decimals;
constructor(string memory _name, string memory _symbol, uint8 _decimals) public {
name = _name;
symbol = _symbol;
decimals = _decimals;
}
}
pragma solidity 0.5.17;
contract ERC20GatewayWhitelist is ERC20 {
address public mainchainGateway;
function allowance(address _owner, address _spender)
public
view
returns (uint256 _value)
{
if (_spender == mainchainGateway) return uint256(-1);
return _allowance[_owner][_spender];
}
function transferFrom(
address _from,
address _to,
uint256 _value
)
public
returns (bool _success)
{
if (allowance(_from, msg.sender) != uint256(-1)) {
super._approve(_from, msg.sender, _allowance[_from][msg.sender].sub(_value));
}
_transfer(_from, _to, _value);
return true;
}
function _setGateway(address _mainchainGateway) internal {
require(
_mainchainGateway != address(0),
"ERC20GatewayWhitelist: setting gateway to the zero address"
);
mainchainGateway = _mainchainGateway;
}
}
pragma solidity 0.5.17;
contract AXSToken is ERC20Detailed, ERC20GatewayWhitelist {
constructor(address _mainchainGateway)
public
ERC20Detailed("Axie Infinity Shard", "AXS", 18)
{
totalSupply = uint256(270000000).mul(uint256(10)**18);
balanceOf[msg.sender] = totalSupply;
emit Transfer(address(0), msg.sender, totalSupply);
_setGateway(_mainchainGateway);
}
}