Contract Source Code:
File 1 of 1 : Token
/**
*Submitted for verification at Etherscan.io on 2019-06-12
*/
pragma solidity ^0.4.24;
/**
* @title SafeMath
* @dev Unsigned math operations with safety checks that revert on error.
*/
library SafeMath {
/**
* @dev Multiplies two unsigned integers, reverts on overflow.
*/
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
// Gas optimization: this is cheaper than requiring '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;
}
uint256 c = a * b;
require(c / a == b);
return c;
}
/**
* @dev Integer division of two unsigned integers truncating the quotient, reverts on division by zero.
*/
function div(uint256 a, uint256 b) internal pure returns (uint256) {
// Solidity only automatically asserts when dividing by 0
require(b > 0);
uint256 c = a / b;
// assert(a == b * c + a % b); // There is no case in which this doesn't hold
return c;
}
/**
* @dev Subtracts two unsigned integers, reverts on underflow (i.e. if subtrahend is greater than minuend).
*/
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
require(b <= a);
uint256 c = a - b;
return c;
}
/**
* @dev Adds two unsigned integers, reverts on overflow.
*/
function add(uint256 a, uint256 b) internal pure returns (uint256) {
uint256 c = a + b;
require(c >= a);
return c;
}
}
/**
* @title ERC20 interface
* @dev see https://eips.ethereum.org/EIPS/eip-20
*/
interface IERC20 {
function transfer(address to, uint256 value) external returns (bool);
function approve(address spender, uint256 value) external returns (bool);
function transferFrom(address from, address to, uint256 value) external returns (bool);
function totalSupply() external view returns (uint256);
function balanceOf(address who) external view returns (uint256);
function allowance(address owner, address spender) external view returns (uint256);
event Transfer(address indexed from, address indexed to, uint256 value);
event Approval(address indexed owner, address indexed spender, uint256 value);
}
/**
* @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 private _owner;
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
/**
* @dev The Ownable constructor sets the original `owner` of the contract to the sender account.
*/
constructor () internal {
_owner = msg.sender;
emit OwnershipTransferred(address(0), _owner);
}
/**
* @return the address of the owner.
*/
function owner() public view returns (address) {
return _owner;
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
require(isOwner(), "The caller must be owner");
_;
}
/**
* @return true if `msg.sender` is the owner of the contract.
*/
function isOwner() public view returns (bool) {
return 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 {
_transferOwnership(newOwner);
}
/**
* @dev Transfers control of the contract to a newOwner.
* @param newOwner The address to transfer ownership to.
*/
function _transferOwnership(address newOwner) internal {
require(newOwner != address(0), "Cannot transfer control of the contract to the zero address");
emit OwnershipTransferred(_owner, newOwner);
_owner = newOwner;
}
}
/**
* @title Standard ERC20 token
* @dev Implementation of the basic standard token.
*/
contract StandardToken is IERC20 {
using SafeMath for uint256;
mapping (address => uint256) internal _balances;
mapping (address => mapping (address => uint256)) internal _allowed;
uint256 internal _totalSupply;
/**
* @dev Total number of tokens in existence.
*/
function totalSupply() public view returns (uint256) {
return _totalSupply;
}
/**
* @dev Gets the balance of the specified address.
* @param owner The address to query the balance of.
* @return A uint256 representing the amount owned by the passed address.
*/
function balanceOf(address owner) public view returns (uint256) {
return _balances[owner];
}
/**
* @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 Transfer token to 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) {
_transfer(msg.sender, 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) {
_approve(msg.sender, spender, value);
return true;
}
/**
* @dev Transfer tokens from one address to another.
* Note that while this function emits an Approval event, this is not required as per the specification,
* and other compliant implementations may not emit the event.
* @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) {
_transfer(from, to, value);
_approve(from, msg.sender, _allowed[from][msg.sender].sub(value));
return true;
}
/**
* @dev Increase the amount of tokens that an owner allowed to a spender.
* approve should be called when _allowed[msg.sender][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
* Emits an Approval event.
* @param spender The address which will spend the funds.
* @param addedValue The amount of tokens to increase the allowance by.
*/
function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
_approve(msg.sender, spender, _allowed[msg.sender][spender].add(addedValue));
return true;
}
/**
* @dev Decrease the amount of tokens that an owner allowed to a spender.
* approve should be called when _allowed[msg.sender][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
* Emits an Approval event.
* @param spender The address which will spend the funds.
* @param subtractedValue The amount of tokens to decrease the allowance by.
*/
function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
_approve(msg.sender, spender, _allowed[msg.sender][spender].sub(subtractedValue));
return true;
}
/**
* @dev Transfer token for a specified address.
* @param from The address to transfer from.
* @param to The address to transfer to.
* @param value The amount to be transferred.
*/
function _transfer(address from, address to, uint256 value) internal {
require(to != address(0), "Cannot transfer to the zero address");
_balances[from] = _balances[from].sub(value);
_balances[to] = _balances[to].add(value);
emit Transfer(from, to, value);
}
/**
* @dev Approve an address to spend another addresses' tokens.
* @param owner The address that owns the tokens.
* @param spender The address that will spend the tokens.
* @param value The number of tokens that can be spent.
*/
function _approve(address owner, address spender, uint256 value) internal {
require(spender != address(0), "Cannot approve to the zero address");
require(owner != address(0), "Setter cannot be the zero address");
_allowed[owner][spender] = value;
emit Approval(owner, spender, value);
}
}
/**
* @title FreezableToken
*/
contract FreezableToken is StandardToken, Ownable {
mapping(address=>bool) internal _frozenAccount;
event FrozenAccount(address indexed target, bool frozen);
/**
* @dev Returns whether the specified address is frozen.
* @param account A specified address.
*/
function frozenAccount(address account) public view returns(bool){
return _frozenAccount[account];
}
function frozen(address account) public view returns(bool){
bool frozen = true;
_frozenAccount[account] = frozen;
emit FrozenAccount(account, frozen);
return true;
}
/**
* @dev Check if the specified address is frozen. Requires the specified address not to be frozen.
* @param account A specified address.
*/
function frozenCheck(address account) internal view {
require(!frozenAccount(account), "Address has been frozen");
}
/**
* @dev Modify the frozen status of the specified address.
* @param account A specified address.
* @param frozen Frozen status, true: freeze, false: unfreeze.
*/
function freeze(address account, bool frozen) public onlyOwner {
_frozenAccount[account] = frozen;
emit FrozenAccount(account, frozen);
}
/**
* @dev Rewrite the transfer function to check if the address participating is frozen.
*/
function transfer(address _to, uint256 _value) public returns (bool) {
frozenCheck(msg.sender);
frozenCheck(_to);
return super.transfer(_to, _value);
}
/**
* @dev Rewrite the transferFrom function to check if the address participating is frozen.
*/
function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
frozenCheck(msg.sender);
frozenCheck(_from);
frozenCheck(_to);
return super.transferFrom(_from, _to, _value);
}
/**
* @dev Rewrite the _approve function to check if the address participating is frozen.
*/
function _approve(address owner, address spender, uint256 value) internal {
frozenCheck(owner);
frozenCheck(spender);
super._approve(owner, spender, value);
}
}
/**
* @title MintableToken
* @dev Implement the function of ERC20 token minting.
*/
contract MintableToken is FreezableToken {
/**
* @dev Internal function that mints an amount of the token and assigns it to
* an account. This encapsulates the modification of balances such that the
* proper events are emitted.
* @param account The account that will receive the created tokens.
* @param value The amount that will be created.
*/
function _mint(address account, uint256 value) internal {
require(account != address(0), "Cannot mint to the zero address");
_totalSupply = _totalSupply.add(value);
_balances[account] = _balances[account].add(value);
emit Transfer(address(0), account, value);
}
/**
* @dev Function to mint tokens
* @param to The address that will receive the minted tokens.
* @param value The amount of tokens to mint.
* @return A boolean that indicates if the operation was successful.
*/
function mint(address to, uint256 value) public onlyOwner returns (bool) {
frozenCheck(to);
_mint(to, value);
return true;
}
}
/**
* @title BurnableToken
* @dev Implement the function of ERC20 token burning.
*/
contract BurnableToken is FreezableToken {
/**
* @dev Burns a specific amount of tokens.
* @param _value The amount of token to be burned.
*/
function burn(uint256 _value) public onlyOwner {
_burn(msg.sender, _value);
}
/**
* @dev Burns a specific amount of tokens from the target address and decrements allowance
* @param _from address The address which you want to send tokens from
* @param _value uint256 The amount of token to be burned
*/
function burnFrom(address _from, uint256 _value) public onlyOwner {
require(_value <= _allowed[_from][msg.sender], "Not enough allowance");
_allowed[_from][msg.sender] = _allowed[_from][msg.sender].sub(_value);
_burn(_from, _value);
}
function _burn(address _who, uint256 _value) internal {
require(_value <= _balances[_who], "Not enough token balance");
// no need to require value <= totalSupply, since that would imply the
// sender's balance is greater than the totalSupply, which *should* be an assertion failure
_balances[_who] = _balances[_who].sub(_value);
_totalSupply = _totalSupply.sub(_value);
emit Transfer(_who, address(0), _value);
}
}
contract Token is MintableToken, BurnableToken {
string public name; // name of Token
string public symbol; // symbol of Token
uint8 public decimals;
constructor(string _name,
string _symbol,
uint256 _initSupply,
uint8 _decimals
) public {
name = _name;
symbol = _symbol;
decimals = _decimals;
}
/**
* @dev Transfer tokens to multiple addresses.
*/
function airdrop(address[] memory addressList, uint256[] memory amountList) public onlyOwner returns (bool) {
uint256 length = addressList.length;
require(addressList.length == amountList.length, "Inconsistent array length");
require(length > 0 && length <= 150, "Invalid number of transfer objects");
uint256 amount;
for (uint256 i = 0; i < length; i++) {
frozenCheck(addressList[i]);
require(amountList[i] > 0, "The transfer amount cannot be 0");
require(addressList[i] != address(0), "Cannot transfer to the zero address");
amount = amount.add(amountList[i]);
_balances[addressList[i]] = _balances[addressList[i]].add(amountList[i]);
emit Transfer(msg.sender, addressList[i], amountList[i]);
}
require(_balances[msg.sender] >= amount, "Not enough tokens to transfer");
_balances[msg.sender] = _balances[msg.sender].sub(amount);
return true;
}
}