pragma solidity ^0.4.23;
/**
* @title SafeMath
* @dev Math operations with safety checks that throw on error
*/
library SafeMath {
/**
* @dev Multiplies two numbers, throws on overflow.
*/
function mul(uint256 a, uint256 b) internal pure returns (uint256 c) {
if (a == 0) {
return 0;
}
c = a * b;
assert(c / a == b);
return c;
}
/**
* @dev Integer division of two numbers, truncating the quotient.
*/
function div(uint256 a, uint256 b) internal pure returns (uint256) {
// assert(b > 0); // Solidity automatically throws when dividing by 0
// uint256 c = a / b;
// assert(a == b * c + a % b); // There is no case in which this doesn't hold
return a / b;
}
/**
* @dev Subtracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
*/
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
assert(b <= a);
return a - b;
}
/**
* @dev Adds two numbers, throws on overflow.
*/
function add(uint256 a, uint256 b) internal pure returns (uint256 c) {
c = a + b;
assert(c >= a);
return c;
}
}
/**
* @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 public 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() public {
owner = msg.sender;
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
require(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 {
require(newOwner != address(0));
emit OwnershipTransferred(owner, newOwner);
owner = newOwner;
}
}
interface IFreezableToken {
event Transfer(address indexed from, address indexed to, uint256 value);
event Approval(address indexed owner, address indexed spender, uint256 value);
event Freeze(address indexed owner, address indexed user, bool status);
function totalSupply() external view returns (uint256);
function balanceOf(address who) external view returns (uint256);
function transfer(address to, uint256 value) external returns (bool);
function allowance(address owner, address spender) external view returns (uint256);
function transferFrom(address from, address to, uint256 value) external returns (bool);
function approve(address spender, uint256 value) external returns (bool);
function increaseApproval(address spender, uint256 addedValue) external returns (bool);
function decreaseApproval(address spender, uint256 subtractedValue) external returns (bool);
function freeze(address user) external returns (bool);
function unfreeze(address user) external returns (bool);
function freezing(address user) external view returns (bool);
}
contract FreezableToken is Ownable, IFreezableToken {
using SafeMath for uint256;
mapping(address => uint256) balances;
mapping(address => mapping(address => uint256)) internal allowed;
mapping(address => bool) frozen;
modifier unfreezing(address user) {
require(!frozen[user], "Cannot transfer from a freezing address");
_;
}
uint256 internal _totalSupply;
/**
* @dev total number of tokens in existence
*/
function totalSupply() public view returns (uint256) {
return _totalSupply;
}
/**
* @dev transfer token for a specified address
* @param _to The address to transfer to.
* @param _value The amount to be transferred.
*/
function transfer(address _to, uint256 _value) public unfreezing(msg.sender) returns (bool) {
require(_to != address(0));
require(_value <= balances[msg.sender]);
balances[msg.sender] = balances[msg.sender].sub(_value);
balances[_to] = balances[_to].add(_value);
emit Transfer(msg.sender, _to, _value);
return true;
}
/**
* @dev Gets the balance of the specified address.
* @param _owner The address to query the the balance of.
* @return An uint256 representing the amount owned by the passed address.
*/
function balanceOf(address _owner) public view returns (uint256 balance) {
return balances[_owner];
}
/**
* @dev Transfer tokens from one address to another
* @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 unfreezing(_from) returns (bool) {
require(_to != address(0));
require(_value <= balances[_from]);
require(_value <= allowed[_from][msg.sender]);
balances[_from] = balances[_from].sub(_value);
balances[_to] = balances[_to].add(_value);
allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
emit Transfer(_from, _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) {
require(_spender != address(0));
allowed[msg.sender][_spender] = _value;
emit Approval(msg.sender, _spender, _value);
return true;
}
/**
* @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 Increase the amount of tokens that an owner allowed to a spender.
*
* approve should be called when allowed[_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
* @param _spender The address which will spend the funds.
* @param _addedValue The amount of tokens to increase the allowance by.
*/
function increaseApproval(address _spender, uint256 _addedValue) public returns (bool) {
require(_spender != address(0));
allowed[msg.sender][_spender] = allowed[msg.sender][_spender].add(_addedValue);
emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
return true;
}
/**
* @dev Decrease the amount of tokens that an owner allowed to a spender.
*
* approve should be called when allowed[_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
* @param _spender The address which will spend the funds.
* @param _subtractedValue The amount of tokens to decrease the allowance by.
*/
function decreaseApproval(address _spender, uint256 _subtractedValue) public returns (bool) {
require(_spender != address(0));
uint256 oldValue = allowed[msg.sender][_spender];
if (_subtractedValue > oldValue) {
allowed[msg.sender][_spender] = 0;
} else {
allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue);
}
emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
return true;
}
/**
* @dev Freeze the balance of the specified address
* @param _user The address to freeze the balance
* @return The boolean status of freezing
*/
function freeze(address _user) public onlyOwner returns (bool) {
frozen[_user] = true;
emit Freeze(msg.sender, _user, true);
return true;
}
/**
* @dev Unfreeze the balance of the specified address
* @param _user The address to unfreeze the balance
* @return The boolean status of freezing
*/
function unfreeze(address _user) public onlyOwner returns (bool) {
frozen[_user] = false;
emit Freeze(msg.sender, _user, false);
return false;
}
/**
* @dev Gets the freezing status of the specified address.
* @param _user The address to query the the balance of.
* @return An uint256 representing the amount owned by the passed address.
*/
function freezing(address _user) public view returns (bool) {
return frozen[_user];
}
}
interface IKAT {
function name() external view returns (string);
function symbol() external view returns (string);
function decimals() external view returns (uint256);
}
/**
* @title KAT Token
*
* @dev Constructor of the deployment
*/
contract KAT is FreezableToken, IKAT {
string private _name;
string private _symbol;
uint256 private _decimals;
/**
* @dev constructor
*/
constructor() public {
_name = "Kambria Token";
_symbol = "KAT";
_decimals = 18;
_totalSupply = 5000000000 * 10 ** _decimals;
balances[msg.sender] = _totalSupply; // coinbase
}
function name() public view returns (string) {
return _name;
}
function symbol() public view returns (string) {
return _symbol;
}
function decimals() public view returns (uint256) {
return _decimals;
}
}
{
"compilationTarget": {
"KAT.sol": "KAT"
},
"evmVersion": "byzantium",
"libraries": {},
"optimizer": {
"enabled": false,
"runs": 200
},
"remappings": []
}
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