Contract Source Code:
File 1 of 1 : USDT
pragma solidity 0.8.0;
abstract contract ERC20 {
uint256 private _totalSupply;
mapping(address => uint256) internal _balances;
mapping(address => mapping(address => uint256)) internal _allowances;
event Transfer(address indexed from, address indexed to, uint256 amount);
event Approval(
address indexed owner,
address indexed spender,
uint256 amount
);
/*
* Internal Functions for ERC20 standard logics
*/
function _transfer(address from, address to, uint256 amount)
internal
returns (bool success)
{
_balances[from] = _balances[from] - amount;
_balances[to] = _balances[to] + amount;
emit Transfer(from, to, amount);
success = true;
}
function _approve(address owner, address spender, uint256 amount)
internal
returns (bool success)
{
_allowances[owner][spender] = amount;
emit Approval(owner, spender, amount);
success = true;
}
function _mint(address recipient, uint256 amount)
internal
returns (bool success)
{
_totalSupply = _totalSupply + amount;
_balances[recipient] = _balances[recipient] + amount;
emit Transfer(address(0), recipient, amount);
success = true;
}
function _burn(address burned, uint256 amount)
internal
returns (bool success)
{
_balances[burned] = _balances[burned] - amount;
_totalSupply = _totalSupply - amount;
emit Transfer(burned, address(0), amount);
success = true;
}
/*
* public view functions to view common data
*/
function totalSupply() external view returns (uint256 total) {
total = _totalSupply;
}
function balanceOf(address owner) external view returns (uint256 balance) {
balance = _balances[owner];
}
function allowance(address owner, address spender)
external
view
returns (uint256 remaining)
{
remaining = _allowances[owner][spender];
}
/*
* External view Function Interface to implement on final contract
*/
function name() virtual external view returns (string memory tokenName);
function symbol() virtual external view returns (string memory tokenSymbol);
function decimals() virtual external view returns (uint8 tokenDecimals);
/*
* External Function Interface to implement on final contract
*/
function transfer(address to, uint256 amount)
virtual
external
returns (bool success);
function transferFrom(address from, address to, uint256 amount)
virtual
external
returns (bool success);
function approve(address spender, uint256 amount)
virtual
external
returns (bool success);
}
// File contracts/library/Ownable.sol
pragma solidity 0.8.0;
abstract contract Ownable {
address internal _owner;
event OwnershipTransferred(
address indexed currentOwner,
address indexed newOwner
);
constructor() {
_owner = msg.sender;
emit OwnershipTransferred(address(0), msg.sender);
}
modifier onlyOwner() {
require(
msg.sender == _owner,
"Ownable : Function called by unauthorized user."
);
_;
}
function owner() external view returns (address ownerAddress) {
ownerAddress = _owner;
}
function transferOwnership(address newOwner)
public
onlyOwner
returns (bool success)
{
require(newOwner != address(0), "Ownable/transferOwnership : cannot transfer ownership to zero address");
success = _transferOwnership(newOwner);
}
function renounceOwnership() external onlyOwner returns (bool success) {
success = _transferOwnership(address(0));
}
function _transferOwnership(address newOwner) internal returns (bool success) {
emit OwnershipTransferred(_owner, newOwner);
_owner = newOwner;
success = true;
}
}
// File contracts/erc20/ERC20Lockable.sol
abstract contract ERC20Lockable is ERC20, Ownable {
struct LockInfo {
uint256 amount;
uint256 due;
}
mapping(address => LockInfo[]) internal _locks;
mapping(address => uint256) internal _totalLocked;
event Lock(address indexed from, uint256 amount, uint256 due);
event Unlock(address indexed from, uint256 amount);
modifier checkLock(address from, uint256 amount) {
require(_balances[from] >= _totalLocked[from] + amount, "ERC20Lockable/Cannot send more than unlocked amount");
_;
}
function _lock(address from, uint256 amount, uint256 due)
internal
returns (bool success)
{
require(due > block.timestamp, "ERC20Lockable/lock : Cannot set due to past");
require(
_balances[from] >= amount + _totalLocked[from],
"ERC20Lockable/lock : locked total should be smaller than balance"
);
_totalLocked[from] = _totalLocked[from] + amount;
_locks[from].push(LockInfo(amount, due));
emit Lock(from, amount, due);
success = true;
}
function _unlock(address from, uint256 index) internal returns (bool success) {
LockInfo storage lock = _locks[from][index];
_totalLocked[from] = _totalLocked[from] - lock.amount;
emit Unlock(from, lock.amount);
_locks[from][index] = _locks[from][_locks[from].length - 1];
_locks[from].pop();
success = true;
}
function unlock(address from, uint256 idx) external returns(bool success){
require(_locks[from][idx].due < block.timestamp,"ERC20Lockable/unlock: cannot unlock before due");
return _unlock(from, idx);
}
function unlockAll(address from) external returns (bool success) {
for(uint256 i = 0; i < _locks[from].length;){
i++;
if(_locks[from][i - 1].due < block.timestamp){
if(_unlock(from, i - 1)){
i--;
}
}
}
success = true;
}
function releaseLock(address from)
external
onlyOwner
returns (bool success)
{
for(uint256 i = 0; i < _locks[from].length;){
i++;
if(_unlock(from, i - 1)){
i--;
}
}
success = true;
}
function transferWithLockUp(address recipient, uint256 amount, uint256 due)
external
onlyOwner
returns (bool success)
{
require(
recipient != address(0),
"ERC20Lockable/transferWithLockUp : Cannot send to zero address"
);
_transfer(msg.sender, recipient, amount);
_lock(recipient, amount, due);
success = true;
}
function lockInfo(address locked, uint256 index)
external
view
returns (uint256 amount, uint256 due)
{
LockInfo memory lock = _locks[locked][index];
amount = lock.amount;
due = lock.due;
}
function totalLocked(address locked) external view returns(uint256 amount, uint256 length){
amount = _totalLocked[locked];
length = _locks[locked].length;
}
}
pragma solidity 0.8.0;
contract Pausable is Ownable {
bool internal _paused;
event Paused();
event Unpaused();
modifier whenPaused() {
require(_paused, "Paused : This function can only be called when paused");
_;
}
modifier whenNotPaused() {
require(!_paused, "Paused : This function can only be called when not paused");
_;
}
function pause() external onlyOwner whenNotPaused returns (bool success) {
_paused = true;
emit Paused();
success = true;
}
function unPause() external onlyOwner whenPaused returns (bool success) {
_paused = false;
emit Unpaused();
success = true;
}
function paused() external view returns (bool) {
return _paused;
}
}
// File contracts/erc20/ERC20Burnable.sol
abstract contract ERC20Burnable is ERC20, Pausable {
event Burn(address indexed burned, uint256 amount);
function burn(uint256 amount)
external
whenNotPaused
returns (bool success)
{
success = _burn(msg.sender, amount);
emit Burn(msg.sender, amount);
success = true;
}
function burnFrom(address burned, uint256 amount)
external
whenNotPaused
returns (bool success)
{
_burn(burned, amount);
emit Burn(burned, amount);
success = _approve(
burned,
msg.sender,
_allowances[burned][msg.sender] - amount
);
}
}
pragma solidity 0.8.0;
contract Freezable is Ownable {
mapping(address => bool) private _frozen;
event Freeze(address indexed target);
event Unfreeze(address indexed target);
modifier whenNotFrozen(address target) {
require(!_frozen[target], "Freezable : target is frozen");
_;
}
function freeze(address target) external onlyOwner returns (bool success) {
_frozen[target] = true;
emit Freeze(target);
success = true;
}
function unFreeze(address target)
external
onlyOwner
returns (bool success)
{
_frozen[target] = false;
emit Unfreeze(target);
success = true;
}
function isFrozen(address target)
external
view
returns (bool frozen)
{
return _frozen[target];
}
}
// File contracts/USDT.sol
// SPDX-License-Identifier: MIT
pragma solidity 0.8.0;
contract USDT is
ERC20Lockable,
ERC20Burnable,
Freezable
{
string constant private _name = "USDT";
string constant private _symbol = "USDT";
uint8 constant private _decimals = 18;
uint256 constant private _initial_supply = 1_000_000_000;
constructor() Ownable() {
_mint(msg.sender, _initial_supply * (10**uint256(_decimals)));
}
function transfer(address to, uint256 amount)
override
external
whenNotFrozen(msg.sender)
whenNotPaused
checkLock(msg.sender, amount)
returns (bool success)
{
require(
to != address(0),
"USDT/transfer : Should not send to zero address"
);
_transfer(msg.sender, to, amount);
success = true;
}
function transferFrom(address from, address to, uint256 amount)
override
external
whenNotFrozen(from)
whenNotPaused
checkLock(from, amount)
returns (bool success)
{
require(
to != address(0),
"USDT/transferFrom : Should not send to zero address"
);
_transfer(from, to, amount);
_approve(
from,
msg.sender,
_allowances[from][msg.sender] - amount
);
success = true;
}
function approve(address spender, uint256 amount)
override
external
returns (bool success)
{
require(
spender != address(0),
"USDT/approve : Should not approve zero address"
);
_approve(msg.sender, spender, amount);
success = true;
}
function name() override external pure returns (string memory tokenName) {
tokenName = _name;
}
function symbol() override external pure returns (string memory tokenSymbol) {
tokenSymbol = _symbol;
}
function decimals() override external pure returns (uint8 tokenDecimals) {
tokenDecimals = _decimals;
}
}