LinkToken
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
pragma solidity ^0.4.16; | |
/** | |
* @title SafeMath | |
* @dev Math operations with safety checks that throw on error | |
*/ | |
library SafeMath { | |
function mul(uint256 a, uint256 b) internal constant returns (uint256) { | |
uint256 c = a * b; | |
assert(a == 0 || c / a == b); | |
return c; | |
} | |
function div(uint256 a, uint256 b) internal constant 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 constant returns (uint256) { | |
assert(b <= a); | |
return a - b; | |
} | |
function add(uint256 a, uint256 b) internal constant returns (uint256) { | |
uint256 c = a + b; | |
assert(c >= a); | |
return c; | |
} | |
} | |
/** | |
* @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) constant returns (uint256); | |
function transfer(address to, uint256 value) 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) constant returns (uint256); | |
function transferFrom(address from, address to, uint256 value) returns (bool); | |
function approve(address spender, uint256 value) returns (bool); | |
event Approval(address indexed owner, address indexed spender, uint256 value); | |
} | |
contract ERC677 is ERC20 { | |
function transferAndCall(address to, uint value, bytes data) returns (bool success); | |
event Transfer(address indexed from, address indexed to, uint value, bytes data); | |
} | |
contract ERC677Receiver { | |
function onTokenTransfer(address _sender, uint _value, bytes _data); | |
} | |
/** | |
* @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) returns (bool) { | |
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) constant 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)) 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) returns (bool) { | |
var _allowance = allowed[_from][msg.sender]; | |
// Check is not needed because sub(_allowance, _value) will already throw if this condition is not met | |
// require (_value <= _allowance); | |
balances[_from] = balances[_from].sub(_value); | |
balances[_to] = balances[_to].add(_value); | |
allowed[_from][msg.sender] = _allowance.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. | |
* @param _spender The address which will spend the funds. | |
* @param _value The amount of tokens to be spent. | |
*/ | |
function approve(address _spender, uint256 _value) 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) constant returns (uint256 remaining) { | |
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) | |
returns (bool success) { | |
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) | |
returns (bool success) { | |
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; | |
} | |
} | |
contract ERC677Token is ERC677 { | |
/** | |
* @dev transfer token to a contract address with additional data if the recipient is a contact. | |
* @param _to The address to transfer to. | |
* @param _value The amount to be transferred. | |
* @param _data The extra data to be passed to the receiving contract. | |
*/ | |
function transferAndCall(address _to, uint _value, bytes _data) | |
public | |
returns (bool success) | |
{ | |
super.transfer(_to, _value); | |
Transfer(msg.sender, _to, _value, _data); | |
if (isContract(_to)) { | |
contractFallback(_to, _value, _data); | |
} | |
return true; | |
} | |
// PRIVATE | |
function contractFallback(address _to, uint _value, bytes _data) | |
private | |
{ | |
ERC677Receiver receiver = ERC677Receiver(_to); | |
receiver.onTokenTransfer(msg.sender, _value, _data); | |
} | |
function isContract(address _addr) | |
private | |
returns (bool hasCode) | |
{ | |
uint length; | |
assembly { length := extcodesize(_addr) } | |
return length > 0; | |
} | |
} | |
contract LinkToken is StandardToken, ERC677Token { | |
uint public constant totalSupply = 10**27; | |
string public constant name = 'ChainLink Token'; | |
uint8 public constant decimals = 18; | |
string public constant symbol = 'LINK'; | |
function LinkToken() | |
public | |
{ | |
balances[msg.sender] = totalSupply; | |
} | |
/** | |
* @dev transfer token to a specified address with additional data if the recipient is a contract. | |
* @param _to The address to transfer to. | |
* @param _value The amount to be transferred. | |
* @param _data The extra data to be passed to the receiving contract. | |
*/ | |
function transferAndCall(address _to, uint _value, bytes _data) | |
public | |
validRecipient(_to) | |
returns (bool success) | |
{ | |
return super.transferAndCall(_to, _value, _data); | |
} | |
/** | |
* @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, uint _value) | |
public | |
validRecipient(_to) | |
returns (bool success) | |
{ | |
return super.transfer(_to, _value); | |
} | |
/** | |
* @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender. | |
* @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 | |
validRecipient(_spender) | |
returns (bool) | |
{ | |
return super.approve(_spender, _value); | |
} | |
/** | |
* @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 | |
validRecipient(_to) | |
returns (bool) | |
{ | |
return super.transferFrom(_from, _to, _value); | |
} | |
// MODIFIERS | |
modifier validRecipient(address _recipient) { | |
require(_recipient != address(0) && _recipient != address(this)); | |
_; | |
} | |
} |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment