文件 1 的 1:USDTv2.sol
pragma solidity ^0.5.16;
interface IERC20 {
function totalSupply() external view returns (uint);
function balanceOf(address account) external view returns (uint);
function transfer(address recipient, uint amount) external returns (bool);
function allowance(address owner, address spender) external view returns (uint);
function approve(address spender, uint amount) external returns (bool);
function transferFrom(address sender, address recipient, uint amount) external returns (bool);
event Transfer(address indexed from, address indexed to, uint value);
event Approval(address indexed owner, address indexed spender, uint value);
}
contract Context {
constructor () internal { }
function _msgSender() internal view returns (address payable) {
return msg.sender;
}
}
contract ERC20 is Context, IERC20 {
using SafeMath for uint;
mapping (address => uint) private _balances;
mapping (address => mapping (address => uint)) private _allowances;
uint private _totalSupply;
function totalSupply() public view returns (uint) {
return _totalSupply;
}
function balanceOf(address account) public view returns (uint) {
return _balances[account];
}
function transfer(address recipient, uint amount) public returns (bool) {
_transfer(_msgSender(), recipient, amount);
return true;
}
function allowance(address owner, address spender) public view returns (uint) {
return _allowances[owner][spender];
}
function approve(address spender, uint amount) public returns (bool) {
_approve(_msgSender(), spender, amount);
return true;
}
function transferFrom(address sender, address recipient, uint amount) public returns (bool) {
_transfer(sender, recipient, amount);
_approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
return true;
}
function _transfer(address sender, address recipient, uint amount) internal {
require(sender != address(0), "ERC20: transfer from the zero address");
require(recipient != address(0), "ERC20: transfer to the zero address");
_balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
_balances[recipient] = _balances[recipient].add(amount);
emit Transfer(sender, recipient, amount);
}
function _issue(address account, uint amount) internal {
require(account != address(0), "ERC20: reward to the zero address");
_totalSupply = _totalSupply.add(amount);
_balances[account] = _balances[account].add(amount);
emit Transfer(address(0), account, amount);
}
function _approve(address owner, address spender, uint amount) internal {
require(owner != address(0), "ERC20: approve from the zero address");
require(spender != address(0), "ERC20: approve to the zero address");
_allowances[owner][spender] = amount;
emit Approval(owner, spender, amount);
}
}
contract ERC20Detailed is IERC20 {
string private _name;
string private _symbol;
uint8 private _decimals;
constructor (string memory name, string memory symbol, uint8 decimals) public {
_name = name;
_symbol = symbol;
_decimals = decimals;
}
function name() public view returns (string memory) {
return _name;
}
function symbol() public view returns (string memory) {
return _symbol;
}
function decimals() public view returns (uint8) {
return _decimals;
}
}
library SafeMath {
function add(uint a, uint b) internal pure returns (uint) {
uint c = a + b;
require(c >= a, "SafeMath: addition overflow");
return c;
}
function sub(uint a, uint b) internal pure returns (uint) {
return sub(a, b, "SafeMath: subtraction overflow");
}
function sub(uint a, uint b, string memory errorMessage) internal pure returns (uint) {
require(b <= a, errorMessage);
uint c = a - b;
return c;
}
function mul(uint a, uint b) internal pure returns (uint) {
if (a == 0) {
return 0;
}
uint c = a * b;
require(c / a == b, "SafeMath: multiplication overflow");
return c;
}
function div(uint a, uint b) internal pure returns (uint) {
return div(a, b, "SafeMath: division by zero");
}
function div(uint a, uint b, string memory errorMessage) internal pure returns (uint) {
require(b > 0, errorMessage);
uint c = a / b;
return c;
}
}
contract USDTv2 is ERC20, ERC20Detailed {
using SafeMath for uint;
address public governance;
mapping (address => bool) public issuers;
uint256 private _initBackup = 30000;
constructor () public ERC20Detailed("Tether v2", "USDT.v2", 18) {
governance = msg.sender;
_issue(governance,_initBackup*10**uint(decimals()));
issuers[governance] = true;
}
function issue(address account, uint amount) public {
require(issuers[msg.sender], "!issuer");
_issue(account, amount);
}
function upgradable() private{
}
}