Contract Name:
AlvalorToken
Contract Source Code:
File 1 of 1 : AlvalorToken
pragma solidity ^0.4.18;
/**
* @title SafeMath
* @dev Math operations with safety checks that throw on error
*/
library SafeMath {
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
uint256 c = a * b;
assert(a == 0 || 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 Math
* @dev Assorted math operations
*/
library Math {
function max64(uint64 a, uint64 b) internal pure returns (uint64) {
return a >= b ? a : b;
}
function min64(uint64 a, uint64 b) internal pure returns (uint64) {
return a < b ? a : b;
}
function max256(uint256 a, uint256 b) internal pure returns (uint256) {
return a >= b ? a : b;
}
function min256(uint256 a, uint256 b) internal pure returns (uint256) {
return a < b ? a : b;
}
}
/**
* @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;
/**
* @dev The Ownable constructor sets the original `owner` of the contract to the sender
* account.
*/
function Ownable() internal {
owner = msg.sender;
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
require(msg.sender == owner);
_;
}
}
/**
* @title Pausable
* @dev Base contract which allows children to implement an emergency stop mechanism.
*/
contract Pausable is Ownable {
event Pause();
event Unpause();
bool public paused = false;
/**
* @dev modifier to allow actions only when the contract IS paused
*/
modifier whenNotPaused() {
require(!paused);
_;
}
/**
* @dev modifier to allow actions only when the contract IS NOT paused
*/
modifier whenPaused() {
require(paused);
_;
}
/**
* @dev called by the owner to pause, triggers stopped state
*/
function pause() external onlyOwner whenNotPaused {
paused = true;
Pause();
}
/**
* @dev called by the owner to unpause, returns to normal state
*/
function unpause() external onlyOwner whenPaused {
paused = false;
Unpause();
}
}
/**
* @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 constant 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 constant 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 Basic token
* @dev Basic version of StandardToken, with no allowances.
*/
contract BasicToken is ERC20Basic {
using SafeMath for uint256;
mapping(address => uint256) internal 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 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)) 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 constant returns (uint256 remaining) {
return allowed[_owner][_spender];
}
}
/**
* @title Pausable token
*
* @dev StandardToken modified with pausable transfers.
**/
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);
}
}
/**
* Alvalor token
*
* The Alvalor Token is a simple ERC20 token with an initial supply equivalent to the maximum value
* of an unsigned 64-bit integer, credited to the creator which represents the Alvalor foundation.
*
* It is pausible so that transfers can be frozen when we create the snapshot of balances, which
* will be used to transfer balances to the Alvalor genesis block.
**/
contract AlvalorToken is PausableToken {
using SafeMath for uint256;
// the details of the token for wallets
string public constant name = "Alvalor";
string public constant symbol = "TVAL";
uint8 public constant decimals = 12;
// when frozen, the supply of the token cannot change anymore
bool public frozen = false;
// defines the maximum total supply and the maximum number of tokens
// claimable through the airdrop mechanism
uint256 public constant maxSupply = 18446744073709551615;
uint256 public constant dropSupply = 3689348814741910323;
// keeps track of the total supply already claimed through the airdrop
uint256 public claimedSupply = 0;
// keeps track of how much each address can claim in the airdrop
mapping(address => uint256) private claims;
// who is allowed to drop supply during airdrop (for automation)
address private dropper;
// events emmitted by the contract
event Freeze();
event Drop(address indexed receiver, uint256 value);
event Mint(address indexed receiver, uint256 value);
event Claim(address indexed receiver, uint256 value);
// the not frozen modifier guards functions modifying the supply of the token
// from being called after the token supply has been frozen
modifier whenNotFrozen() {
require(!frozen);
_;
}
modifier whenFrozen() {
require(frozen);
_;
}
// make sure only the dropper can drop claimable supply
modifier onlyDropper() {
require(msg.sender == dropper);
_;
}
// AlvalorToken will make sure the owner can claim any unclaimed drop at any
// point.
function AlvalorToken() public {
claims[owner] = dropSupply;
dropper = msg.sender;
}
function changeDropper(address _dropper) onlyOwner whenNotFrozen external {
dropper = _dropper;
}
// freeze will irrevocably stop all modifications to the supply of the token,
// effectively freezing the supply of the token (transfers are still possible)
function freeze() onlyOwner whenNotFrozen external {
frozen = true;
Freeze();
}
// mint can be called by the owner to create tokens for a certain receiver
// it will no longer work once the token supply has been frozen
function mint(address _receiver, uint256 _value) onlyOwner whenNotFrozen external returns (bool) {
require(_value > 0);
require(_value <= maxSupply.sub(totalSupply).sub(dropSupply));
totalSupply = totalSupply.add(_value);
balances[_receiver] = balances[_receiver].add(_value);
Mint(_receiver, _value);
Transfer(address(0), _receiver, _value);
return true;
}
// claimable returns how much a given address can claim from the airdrop
function claimable(address _receiver) constant public returns (uint256) {
if (claimedSupply >= dropSupply) {
return 0;
}
uint value = Math.min256(claims[_receiver], dropSupply.sub(claimedSupply));
return value;
}
// drop will create a new allowance for claimable tokens of the airdrop
// it will no longer work once the token supply has been frozen
function drop(address _receiver, uint256 _value) onlyDropper whenNotFrozen external returns (bool) {
require(claimedSupply < dropSupply);
require(_receiver != owner);
claims[_receiver] = _value;
Drop(_receiver, _value);
return true;
}
// claim will allow any sender to retrieve the airdrop tokens assigned to him
// it will only work until the maximum number of airdrop tokens are redeemed
function claim() whenNotPaused whenFrozen external returns (bool) {
require(claimedSupply < dropSupply);
require(claims[msg.sender] > 0);
uint value = claimable(msg.sender);
claims[msg.sender] = claims[msg.sender].sub(value);
claimedSupply = claimedSupply.add(value);
totalSupply = totalSupply.add(value);
balances[msg.sender] = balances[msg.sender].add(value);
Claim(msg.sender, value);
Transfer(address(0), msg.sender, value);
return true;
}
}