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ZilliqaToken
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pragma solidity ^0.4.18; | |
/** | |
* @title ERC20Basic | |
* @dev Simpler version of ERC20 interface | |
* @dev see https://github.com/ethereum/EIPs/issues/179 | |
*/ | |
contract ERC20Basic { | |
uint256 public totalSupply; | |
function balanceOf(address who) public view returns (uint256); | |
function transfer(address to, uint256 value) public returns (bool); | |
event Transfer(address indexed from, address indexed to, uint256 value); | |
} | |
/** | |
* @title ERC20 interface | |
* @dev see https://github.com/ethereum/EIPs/issues/20 | |
*/ | |
contract ERC20 is ERC20Basic { | |
function allowance(address owner, address spender) public view returns (uint256); | |
function transferFrom(address from, address to, uint256 value) public returns (bool); | |
function approve(address spender, uint256 value) public returns (bool); | |
event Approval(address indexed owner, address indexed spender, uint256 value); | |
} | |
/** | |
* @title SafeMath | |
* @dev Math operations with safety checks that throw on error | |
*/ | |
library SafeMath { | |
function mul(uint256 a, uint256 b) internal pure returns (uint256) { | |
if (a == 0) { | |
return 0; | |
} | |
uint256 c = a * b; | |
assert(c / a == b); | |
return c; | |
} | |
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 c; | |
} | |
function sub(uint256 a, uint256 b) internal pure returns (uint256) { | |
assert(b <= a); | |
return a - b; | |
} | |
function add(uint256 a, uint256 b) internal pure returns (uint256) { | |
uint256 c = a + b; | |
assert(c >= a); | |
return c; | |
} | |
} | |
/** | |
* @title Basic token | |
* @dev Basic version of StandardToken, with no allowances. | |
*/ | |
contract BasicToken is ERC20Basic { | |
using SafeMath for uint256; | |
mapping(address => uint256) balances; | |
/** | |
* @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 returns (bool) { | |
require(_to != address(0)); | |
require(_value <= balances[msg.sender]); | |
// SafeMath.sub will throw if there is not enough balance. | |
balances[msg.sender] = balances[msg.sender].sub(_value); | |
balances[_to] = balances[_to].add(_value); | |
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]; | |
} | |
} | |
/** | |
* @title Standard ERC20 token | |
* | |
* @dev Implementation of the basic standard token. | |
* @dev https://github.com/ethereum/EIPs/issues/20 | |
* @dev Based on code by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol | |
*/ | |
contract StandardToken is ERC20, BasicToken { | |
mapping (address => mapping (address => uint256)) internal allowed; | |
/** | |
* @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 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); | |
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) { | |
allowed[msg.sender][_spender] = _value; | |
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]; | |
} | |
/** | |
* 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 | |
*/ | |
function increaseApproval(address _spender, uint _addedValue) public returns (bool) { | |
allowed[msg.sender][_spender] = allowed[msg.sender][_spender].add(_addedValue); | |
Approval(msg.sender, _spender, allowed[msg.sender][_spender]); | |
return true; | |
} | |
function decreaseApproval(address _spender, uint _subtractedValue) public returns (bool) { | |
uint oldValue = allowed[msg.sender][_spender]; | |
if (_subtractedValue > oldValue) { | |
allowed[msg.sender][_spender] = 0; | |
} else { | |
allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue); | |
} | |
Approval(msg.sender, _spender, allowed[msg.sender][_spender]); | |
return true; | |
} | |
} | |
/** | |
* @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. | |
*/ | |
function Ownable() 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)); | |
OwnershipTransferred(owner, newOwner); | |
owner = newOwner; | |
} | |
} | |
/** | |
* @title Pausable | |
* @dev Base contract which allows children to implement an emergency stop mechanism. | |
*/ | |
contract Pausable is Ownable { | |
event PausePublic(bool newState); | |
event PauseOwnerAdmin(bool newState); | |
bool public pausedPublic = true; | |
bool public pausedOwnerAdmin = false; | |
address public admin; | |
/** | |
* @dev Modifier to make a function callable based on pause states. | |
*/ | |
modifier whenNotPaused() { | |
if(pausedPublic) { | |
if(!pausedOwnerAdmin) { | |
require(msg.sender == admin || msg.sender == owner); | |
} else { | |
revert(); | |
} | |
} | |
_; | |
} | |
/** | |
* @dev called by the owner to set new pause flags | |
* pausedPublic can't be false while pausedOwnerAdmin is true | |
*/ | |
function pause(bool newPausedPublic, bool newPausedOwnerAdmin) onlyOwner public { | |
require(!(newPausedPublic == false && newPausedOwnerAdmin == true)); | |
pausedPublic = newPausedPublic; | |
pausedOwnerAdmin = newPausedOwnerAdmin; | |
PausePublic(newPausedPublic); | |
PauseOwnerAdmin(newPausedOwnerAdmin); | |
} | |
} | |
contract PausableToken is StandardToken, Pausable { | |
function transfer(address _to, uint256 _value) public whenNotPaused returns (bool) { | |
return super.transfer(_to, _value); | |
} | |
function transferFrom(address _from, address _to, uint256 _value) public whenNotPaused returns (bool) { | |
return super.transferFrom(_from, _to, _value); | |
} | |
function approve(address _spender, uint256 _value) public whenNotPaused returns (bool) { | |
return super.approve(_spender, _value); | |
} | |
function increaseApproval(address _spender, uint _addedValue) public whenNotPaused returns (bool success) { | |
return super.increaseApproval(_spender, _addedValue); | |
} | |
function decreaseApproval(address _spender, uint _subtractedValue) public whenNotPaused returns (bool success) { | |
return super.decreaseApproval(_spender, _subtractedValue); | |
} | |
} | |
contract ZilliqaToken is PausableToken { | |
string public constant name = "Zilliqa"; | |
string public constant symbol = "ZIL"; | |
uint8 public constant decimals = 12; | |
modifier validDestination( address to ) | |
{ | |
require(to != address(0x0)); | |
require(to != address(this)); | |
_; | |
} | |
function ZilliqaToken( address _admin, uint _totalTokenAmount ) | |
{ | |
// assign the admin account | |
admin = _admin; | |
// assign the total tokens to zilliqa | |
totalSupply = _totalTokenAmount; | |
balances[msg.sender] = _totalTokenAmount; | |
Transfer(address(0x0), msg.sender, _totalTokenAmount); | |
} | |
function transfer(address _to, uint _value) validDestination(_to) returns (bool) | |
{ | |
return super.transfer(_to, _value); | |
} | |
function transferFrom(address _from, address _to, uint _value) validDestination(_to) returns (bool) | |
{ | |
return super.transferFrom(_from, _to, _value); | |
} | |
event Burn(address indexed _burner, uint _value); | |
function burn(uint _value) returns (bool) | |
{ | |
balances[msg.sender] = balances[msg.sender].sub(_value); | |
totalSupply = totalSupply.sub(_value); | |
Burn(msg.sender, _value); | |
Transfer(msg.sender, address(0x0), _value); | |
return true; | |
} | |
// save some gas by making only one contract call | |
function burnFrom(address _from, uint256 _value) returns (bool) | |
{ | |
assert( transferFrom( _from, msg.sender, _value ) ); | |
return burn(_value); | |
} | |
function emergencyERC20Drain( ERC20 token, uint amount ) onlyOwner { | |
// owner can drain tokens that are sent here by mistake | |
token.transfer( owner, amount ); | |
} | |
event AdminTransferred(address indexed previousAdmin, address indexed newAdmin); | |
function changeAdmin(address newAdmin) onlyOwner { | |
// owner can re-assign the admin | |
AdminTransferred(admin, newAdmin); | |
admin = newAdmin; | |
} | |
} |
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