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/// token.sol -- ERC20 implementation with minting and burning
// Copyright (C) 2015, 2016, 2017 DappHub, LLC
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <>.
pragma solidity >=0.4.23 <0.7.0;
import "ds-math/math.sol";
import "ds-auth/auth.sol";
contract DSToken is DSMath, DSAuth {
bool public stopped;
uint256 public totalSupply;
mapping (address => uint256) public balanceOf;
mapping (address => mapping (address => uint256)) public allowance;
string public symbol;
uint8 public decimals = 18; // standard token precision. override to customize
string public name = ""; // Optional token name
constructor(string memory symbol_) public {
symbol = symbol_;
event Approval(address indexed src, address indexed guy, uint wad);
event Transfer(address indexed src, address indexed dst, uint wad);
event Mint(address indexed guy, uint wad);
event Burn(address indexed guy, uint wad);
event Stop();
event Start();
modifier stoppable {
require(!stopped, "ds-stop-is-stopped");
function approve(address guy) external returns (bool) {
return approve(guy, uint(-1));
function approve(address guy, uint wad) public stoppable returns (bool) {
allowance[msg.sender][guy] = wad;
emit Approval(msg.sender, guy, wad);
return true;
function transfer(address dst, uint wad) external returns (bool) {
return transferFrom(msg.sender, dst, wad);
function transferFrom(address src, address dst, uint wad)
returns (bool)
if (src != msg.sender && allowance[src][msg.sender] != uint(-1)) {
require(allowance[src][msg.sender] >= wad, "ds-token-insufficient-approval");
allowance[src][msg.sender] = sub(allowance[src][msg.sender], wad);
require(balanceOf[src] >= wad, "ds-token-insufficient-balance");
balanceOf[src] = sub(balanceOf[src], wad);
balanceOf[dst] = add(balanceOf[dst], wad);
emit Transfer(src, dst, wad);
return true;
function push(address dst, uint wad) external {
transferFrom(msg.sender, dst, wad);
function pull(address src, uint wad) external {
transferFrom(src, msg.sender, wad);
function move(address src, address dst, uint wad) external {
transferFrom(src, dst, wad);
function mint(uint wad) external {
mint(msg.sender, wad);
function burn(uint wad) external {
burn(msg.sender, wad);
function mint(address guy, uint wad) public auth stoppable {
balanceOf[guy] = add(balanceOf[guy], wad);
totalSupply = add(totalSupply, wad);
emit Mint(guy, wad);
function burn(address guy, uint wad) public auth stoppable {
if (guy != msg.sender && allowance[guy][msg.sender] != uint(-1)) {
require(allowance[guy][msg.sender] >= wad, "ds-token-insufficient-approval");
allowance[guy][msg.sender] = sub(allowance[guy][msg.sender], wad);
require(balanceOf[guy] >= wad, "ds-token-insufficient-balance");
balanceOf[guy] = sub(balanceOf[guy], wad);
totalSupply = sub(totalSupply, wad);
emit Burn(guy, wad);
function stop() public auth {
stopped = true;
emit Stop();
function start() public auth {
stopped = false;
emit Start();
function setName(string memory name_) public auth {
name = name_;